MX365318B

High efficiency configuration for solar cell string.

Abstract

A high efficiency configuration for a solar cell chain comprises solar cells connected in series arranged in a pattern of overlapping roof tiles. Front and back surface metallization patterns can provide additional increases in efficiency. Alternate sources of energy are needed to meet the world's growing energy demands. Solar energy resources are sufficient in many geographical regions to meet such demands, in part, by providing the electric power generated with solar cells (eg, photovoltaic).

MX365318B, drawing sheet 1 — Sheet 1 of 16

Term

7.1 yearsleft in the term

Expires 8 November 2033.

16 claims: 2 independent, 14 dependent

1
Un aparato que comprende:una pluralidad de celdas solares de silicio rectangulares o sustancialmente rectangulares dispuestas en linea con los lados largos de celdas solares de silicio adyacentes que se superponen y se unen conductivamente entre si con un material de unión eléctricamente conductivo para conectar eléctricamente las celdas solares de silicio en serie para formar una cadena de celdas solares de silicio, cada celda solar de silicio comprende una superficie frontal a ser iluminada con luz y una superficie posterior posicionada opuestamente;en donde la superficie frontal de cada celda solar de silicio comprende: una pluralidad de dedos orientados de manera perpendicular al borde de un primer lado largo de la celda solar de silicio y espaciados a lo largo del primer lado largo con un paso de aproximadamente 0.7 milímetros a aproximadamente 1.2 milímetros;un conductor de derivación que interconecta dos o más de la pluralidad de dedos;y un conductor de extremo que interconecta dos o más de la pluralidad de dedos en sus extremos opuestos desde el borde del primer lado largo de la celda solar de silicio;caracterizado porque para cada par de celdas solares de silicio adyacentes en la cadena de celdas solares de silicio, el material de unión eléctricamente conductivo está unido a, e interconecta eléctricamente los dedos en la superficie frontal de una del par de celdas solares adyacentes al borde del primer lado largo de la celda solar de silicio para llevar a cabo una función de captación de corriente de una barra colectora, el conductor de derivación en la superficie frontal de la celda solar proporciona múltiples trayectorias de corriente entre los dedos y el material de unión eléctricamente conductivo, y el conductor de extremo proporciona trayectorias de corriente adicionales entre los dedos y el material de unión eléctricamente conductivo.
2
El aparato de conformidad con la reivindicación 1, caracterizado porque el material de unión eléctricamente conductivo es un adhesivo eléctricamente conductivo.
3
El aparato de conformidad con la reivindicación 1, caracterizado porque el material de unión eléctricamente conductivo proporciona más conformación mecánica de la que se proporciona por una unión de soldadura eléctricamente conductiva.
4
El aparato de conformidad con la reivindicación 1, caracterizado porque la superficie posterior de cada celda solar de silicio que superpone una superficie frontal de una celda solar de silicio adyacente comprende una barra colectora o una pluralidad de almohadillas de contacto unidas conductivamente a la superficie frontal de la celda solar de silicio adyacente por el material de unión eléctricamente conductivo.
5
El aparato de conformidad con la reivindicación 1, caracterizado porque comprende una interconexión eléctrica que cumple mecánicamente unida conductivamente a la superficie frontal de una de las celdas solares de silicio.
6
El aparato de conformidad con la reivindicación 5, caracterizado porque la interconexión eléctrica que cumple mecánicamente se conecta eléctricamente a un diodo de derivación.
7
El aparato de conformidad con la reivindicación 1, caracterizado porque comprende una interconexión eléctrica que cumple mecánicamente unida conductivamente a la superficie posterior de una de las celdas solares de silicio.
8
El aparato de conformidad con la reivindicación 7, caracterizado porque la interconexión eléctrica que cumple mecánicamente se conecta eléctricamente a un diodo de derivación.
9
El aparato de conformidad con la reivindicación 1, caracterizado porque comprende una interconexión eléctrica que cumple mecánicamente unida conductivamente a la superficie posterior de una de las celdas solares de silicio ubicada en una posición intermedia a lo largo de la cadena de celdas solares de silicio.
10
El aparato de conformidad con la reivindicación 9, caracterizado porque la interconexión eléctrica que cumple mecánicamente se conecta eléctricamente a un diodo de derivación.
11
El aparato de conformidad con la reivindicación 1, caracterizado porque comprende otro conductor de derivación dispuesto en linea con el conductor de derivación e interconecta otros dos o más dedos para proporcionar múltiples trayectorias de corriente de cada uno de los otros dos o más dedos interconectados al material de unión eléctricamente conductivo.
12
El aparato de conformidad con la reivindicación 1, caracterizado porque el conductor de extremo tiene un ancho perpendicular a su eje largo que es el mismo que el ancho de un dedo. 5 13. El aparato de conformidad con la reivindicación 1, caracterizado porque la superficie frontal de cada celda solar de silicio comprende una barra colectora o una pluralidad de almohadillas de contacto ubicadas adyacentes y paralelas al borde del primer lado largo de la celda solar de 10 silicio entre el conductor de derivación y el borde, y para cada par de celdas solares de silicio adyacentes en la cadena de celdas solares de silicio, el material de unión eléctricamente conductivo está unido a la barra colectora o a la pluralidad de almohadillas de contacto.
13
15 14. El aparato de conformidad con la reivindicación 13, caracterizado porque la barra colectora o a la pluralidad de almohadillas de contacto tienen un ancho perpendicular al borde del primer lado largo que es el mismo que el ancho de uno de la pluralidad de dedos. 20 15. El aparato de conformidad con la reivindicación 1, caracterizado porque las superficies frontales de las celdas solares de silicio no comprenden barras colectoras o una pluralidad de almohadillas de contacto paralelas al borde del primer lado largo de la celda solar de silicio entre el conductor de derivación y el borde.
14
16. El aparato de conformidad con cualquiera de las reivindicaciones 1 a 15, caracterizado porque la relación de la longitud de un lado largo de las celdas solares de silicio rectangulares o sustancialmente rectangulares a la longitud de un lado corto de las celdas solares de silicio rectangulares o sustancialmente rectangulares es mayor o igual a tres. 10
15
17. El aparato de conformidad con cualquiera de las reivindicaciones 1 a 16, caracterizado porque se encuentra intercalado entre una lámina superior transparente y un sustrato de vidrio.
16
18. El aparato de conformidad con cualquiera de las 15 reivindicaciones 1 a 17, caracterizado porque la superficie frontal de cada celda solar de silicio comprende alrededor de 125 a alrededor de 225 dedos separados a lo largo del primer lado largo. 100 RESUMEN DE IA INVENCIÓN Una configuración de alta eficiencia para una cadena de celdas solares comprende celdas solares conectadas en serie 5 acomodadas en un patrón de tejamanils superpuestas. Patrones de metalización de superficie frontal y posterior pueden proporcionar aumentos adicionales en la eficiencia. Se necesitan fuentes alternas de energía para satisfacer las demandas de energía a nivel mundial cada vez mayores. Los 10 recursos de energía solar son suficientes en muchas regiones geográficas para satisfacer tales demandas, en parte, al proveer la energía eléctrica generada con celdas solares (p.ej., fotovoltaicas). 1/11 *.·* 2/11 jf' 3/11 ♦* 4/11 O ♦ * 5/11 6C?- 7 6/11 7/ÍJ v t 8¡ Λ · O 9/11 10/11 11/11 X. x. /K\ X χχχ x X X 5 x. y /x/yy i. X x. ' ^ · W·' x%£ V ·χ·ϊ 'χχ— X . . W *£ x í’X'X s .~~ -χίχ . :X,-' XXv X X ) 'x x ^x x '3v xx y x x \X X %.-'X.. Ws ^cy X K $. 'W·'·' *X χΧ ;;' X \\ \ \ x \ 'X \ V

Independent claims16

359 paragraphs in 7 sections, as filed

The invention generally relates to solar cells and their use in the concentration of solar energy collectors.

BACKGROUND OF THE INVENTION

Alternate energy sources are needed to meet the ever-increasing worldwide energy demands. Solar energy resources are sufficient in many geographical regions to meet such demands, in part, by the provision of electrical energy generated by solar cells (eg, photovoltaic).

BRIEF DESCRIPTION OF THE INVENTION

This document discloses high efficiency solar cell accommodations. Solar cells and solar cell chains as disclosed herein may be particularly valuable in the concentration of photovoltaic systems, in which mirrors or lenses concentrate sunlight on a photovoltaic cell for light intensities greater than those of a Sun.

In one aspect, a solar cell comprises a silicon semiconductor diode structure having rectangular or substantially rectangular front and rear surfaces having shapes defined by first and second opposite sides of the solar cell and two opposite sides of the cell. solar. In operation, the front surface lights up

<td>by the light</td><td>The cell</td><td colspan="2">solar comprises a</td><td>Pattern</td><td>from</td>

<td>metallization</td><td>Of surface</td><td>electric front</td><td>camente</td><td>conduct</td><td>ivo</td>

<td>placed in</td><td colspan="2">the front surface</td><td>East</td><td>Pattern</td><td>from</td>

<td>metallization</td><td>includes a</td><td>plurality of</td><td>fingers</td><td>what cor</td><td>rsn</td>

<td>parallel to</td><td>the sides</td><td>short of the</td><td>cell</td><td>solar</td><td>by</td>

substantially the length of the short sides. An electrically conductive back surface metallization pattern is placed on the back surface.

In some variations, the front surface metallization pattern does not include any busbar that interconnects the fingers to capture the current from the front surface of the solar cell. In such variations, the back surface metallization pattern may lack any contact pad conventionally prepared for solder connections to the solar cell. Alternatively, the back surface metallization pattern may include, for example, one or

Μ adjacent positioned contact pad and running parallel to a long side of the solar cell for substantially the length of the long side, or two or more discrete contact pads positioned adjacent and arranged parallel to the long side.

In some variations, the front surface metallization pattern comprises only a single busbar, which is positioned adjacent and runs parallel to the first long side by substantially the length of the first long side. The fingers of the frontal metallization pattern are connected to and interconnected by means of the busbar. In such variations, the back surface metallization pattern may lack any contact pad. Alternatively, the back surface metallization pattern may include, for example, an adjacent positioned contact pad that runs parallel to the second long side by substantially the length of the second long side, or two or more discrete contact pads positioned adjacent and accommodated. parallel to the second long side.

These contact pads may have measured widths perpendicular to the long sides that fit approximately the width of the busbar, for example. In any of these variations, the front surface metallization pattern may include a shunt conductor that has a width perpendicular to its long axis narrower than the width of the busbar and that interconnects two or more fingers to provide multiple current paths from each of the two or more fingers interconnected to the busbar. The bypass conductor may be positioned adjacent and run parallel to the busbar, for example.

In some variations, the front surface metallization pattern comprises two or more discrete contact pads positioned adjacent to the first long side. Each of the fingers of the frontal metallization pattern is electrically connected and connected to at least one of the contact pads. In such variations, the back surface metallization pattern may lack any contact pad. Alternatively, the back surface metallization pattern may include, for example, an adjacent positioned contact pad that runs parallel to the second long side by substantially the length of the second long side, or two or more discrete contact pads positioned adjacent and accommodated. parallel to the second long side.

These contact pads may have measured widths perpendicular to the long sides that fit * * approximately with the width of the contact pads in the front surface metallization pattern, for example. In any of these variations, the front surface metallization pattern may include a shunt conductor that is perpendicular in turn that is shorter than the widths of the front surface metallization contact pads and that interconnects two or more fingers to provide multiple current paths from each of the two or more fingers interconnected to one or more of the contact pads.

In any of the above variations, the solar cell may comprise any suitable silicon semiconductor diode structure. For example, the solar cell may comprise an intrinsic thin layer heterojunction (HIT) structure.

In any of the above variations, the ratio of the length of a long side of the solar cell relative to the length of a short side of the solar cell may be greater than or equal to approximately three, eg emplo.

A concentration solar energy collector may comprise the solar cell of any of the above variations and one or more optical elements arranged to concentrate the solar radiation on the solar cell.

In another aspect, a solar cell chain comprises at least a first silicon solar cell and a second silicon solar cell. The first silicon solar cell comprises a front surface to be illuminated by light, a rear surface, and an electrically conductive front surface metallization pattern placed on the front surface. The second silicon solar cell comprises a front surface to be illuminated by light, a rear surface, and an electrically conductive rear surface metallization pattern placed on the rear surface. The first and second solar cells are positioned with an edge of the rear surface of the second silicon solar cell superimposing an edge of the front surface of the first silicon solar cell. A portion of the front surface metallization pattern of the first silicon solar cell is hidden by the second silicon solar cell and is attached to a portion of the rear surface metallization pattern of the second silicon solar cell with a bonding material electrically conductive to electrically connect the first and second silicon solar cells in series.

Any or both of the first and second silicon solar cells may be, for example, of any of

the variations of the silicon solar cell summarized above. In such variations, the superimposed edges of the silicon solar cells may be defined by long sides of the solar cells, for example, and the edges may be arranged parallel to each other. If the front surface metallization pattern of the first silicon solar cell includes a branch conductor, the branch conductor may be hidden, or not hidden, by the second silicon solar cell.

The first and second solar cells may be joined together in the overlapping portions of the solar cells with an electrically conductive welding. As an alternative to welding, solar cells can rather be joined together with, for example, an electrically conductive film, an electrically conductive paste, an electrically conductive epoxy (e.g., an electrically conductive silver epoxy) , an electrically conductive tape, or other suitable electrically conductive adhesive. These alternatives to welding can be selected, for example, to provide more mechanical compliance than would be provided by means of an electrically conductive welding joint. The electrically conductive bonding material that joins the solar cells between them can also interconnect fingers of the pattern of

front surface metallization to carry out the current pickup function of a busbar. The front surface metallization pattern in solar cells may therefore lack any busbar.

A concentration solar energy collector can comprise the solar cell chain of any of the above variations and one or more optical elements arranged to concentrate the solar radiation on the chain.

In another aspect, a solar energy receiver comprises a metal substrate and a series connected chain of two or more solar cells placed on the metal substrate with the ends of adjacent solar cells superimposing on a tejamanil pattern. The adjacent overlapping pairs of solar cells can be electrically connected in a region where they overlap by means of an electrically conductive junction between the front surface of one of the solar cells and the rear surface of the other solar cell. The electrically conductive junction may be between a metallization pattern on the front surface of a solar cell and a metallization pattern on the rear surface of the other solar cell, for example. The solar cells may be, for example, silicon solar cells, including any of the variations of the silicon solar cells summarized above or any of the variations of the subsequent contact silicon solar cells described below, or configured solar cells of similar to any of those variations, but using another system of material other than or in addition to silicon. The electrically conductive junction between the solar cells can be formed, for example, by any of the methods outlined above. Solar cells can be placed in a rolling stack that adheres to the metal substrate, e.g. empio.

In some variations, the metal substrate is linearly elongated, each of the solar cells is linearly elongated, and the solar cell chain is arranged in a row along a long axis of the metal substrate c.on the long axes of the solar cells oriented perpendicular to the long axis of the metal substrate. This row of solar cells may be the only row of solar cells in the substrate.

In some variations, the chain connected in series of solar cells is a first chain of solar cells, and the solar energy receiver comprises a second chain connected in series of two or more solar cells accommodated with the ends of the solar cells overlapping in a tejamanil pattern. The second solar cell chain is also placed on the metal substrate. A mechanically shaped electrical interconnection can electrically couple the rear surface of a solar cell at one end of the first solar cell chain to the front surface of a solar cell at one end of the second solar cell chain. The interconnection may be between a metallization pattern on the front surface of a solar cell and a metallization pattern on the rear surface of the other solar cell, for example. The solar cell at the end of the first solar cell chain can be superimposed on the solar cell at the end of the second solar cell chain and hide from view the mechanically formed electrical interconnection from the front (illuminated) surface side of the solar cells.

In such variations, the metal substrate may be linearly elongated, each of the solar cells may be linearly elongated, and the first and second solar cell chains may be accommodated in a line along a row along a long axis of the substrate of metal with the long shafts of the solar cells oriented perpendicularly to the larao axis of the metal substrate.

'Μ 1

A concentration solar energy collector may comprise the solar energy receiver of any of the above variations and one or more optical elements arranged to concentrate the solar radiation on the receiver.

In another aspect, a solar cell chain comprises a first group of solar cells accommodated with the ends of adjacent solar cells overlapping in a tejamanil pattern and connected in series by means of electrical connections between solar cells made in the overlapping regions of adjacent solar cells, a second group of solar cells arranged with the ends of the adjacent solar cells superimposing on a tile pattern and connected in series by means of electrical connections between solar cells made in the overlapping regions of the adjacent solar cells, and a shaped electrical interconnection mechanically that electrically couples the first group of solar cells to the second group of solar cells in series. The mechanically shaped electrical interconnection can electrically couple the rear surface of a solar cell at one end of the first group of solar cells to a front surface of a solar cell at one end of the second group of solar cells, for example. The interconnection may be between a metallization pattern on the front surface of a solar cell and a metallization pattern on the rear surface of the other solar cell, for example. The mechanically shaped electrical interconnection can be attached to solar cells with electrically conductive junctions made by any of the methods outlined above, for example.

The solar cells may be, for example, silicon solar cells, including any of the variations of silicon solar cells summarized above or any of the variations of subsequent contact silicon solar cells described below, or solar cells configured in a manner similar to any of those variations but using another system of different material or in addition to silicon. Electrical connections between superimposed solar cells can be made, for example, with electrically conductive junctions made by any of the methods outlined above.

In such variations, a space between the two groups of solar cells where they are interconnected by means of the mechanically shaped electrical interconnection may have a width less than or equal to approximately five millimeters, for example. Also in such variations, the mechanically shaped electrical interconnection may comprise a metal slat oriented perpendicularly to a long axis of the row of solar cells and electrically coupled to a rear surface of a solar cell at one end of the first group of solar cells and to a frontal surface in a solar cell at one end of the second group of solar cells.

The mechanically shaped electrical interconnection in any of the above variations may comprise a pattern metal slat with slits or openings, for example, to increase its mechanical conformation.

In any of the above variations, the solar cell at the end of the first group of solar cells can be superimposed on the solar cell at the end of the second group of solar cells and hide from view the mechanically formed electrical interconnection from the front surface side of the solar cell chain.

A concentration solar energy collector can comprise the solar cell chain of any of the above variations and one or more optical elements arranged to concentrate the solar radiation on the chain.

In another aspect, a solar cell chain comprises at least a first solar cell and a second solar cell.

The first solar cell comprises a front surface to be

I »* illuminated by light, a back surface, and (optionally) an electrically conductive front surface metallization pattern placed on the front surface. The second solar cell comprises a front surface to be illuminated by light, a rear surface, and an electrically conductive rear surface metallization pattern placed on the rear surface. The solar cell chain also comprises at least a first mechanically shaped electrical interconnection. The first and second solar cells are positioned with an edge of the rear surface of the second solar cell superimposing an edge of the front surface of the first solar cell. The mechanically shaped electrical interconnection joins a portion of the front surface of the first solar cell that is hidden by the second solar cell and joins a portion of the rear surface of the second solar cell to electrically connect the first and second cells solar in series. In this arrangement, the second solar cell conceals from view the mechanically formed electrical interconnection from the front surface side of the first solar cell. The interconnection can be between a metallization pattern on the front surface of a solar cell and a metallization pattern on the rear surface

I »* of the other solar cell, for example.

Any or both of the first and second solar cells may be, for example, any of the variations of silicon solar cells summarized above or any of the variations of subsequent contact silicon solar cells described below, or configured solar cells of similar to any of those variations but using another system of different material or in addition to silicon. In such variations, the superimposed edges of the silicon solar cells may be defined by long sides of the solar cells, for example, and the edges may be arranged parallel to each other. If the first solar cell comprises a front surface metallization pattern that includes a branch conductor, the branch conductor may be hidden, or not hidden, by the second solar cell.

The mechanically shaped electrical interconnection can be attached to solar cells with electrically conductive junctions made by any of the methods outlined above, for example. Electrically conductive joints can interconnect fingers of a front surface metallization pattern in the first solar cell, if present, to carry out the current pick-up function of a busbar. A front surface metallization pattern in the solar cell may therefore lack any busbar.

The mechanically shaped electrical interconnection may comprise, for example, a flat metal slat, a folded metal slat, or a spoken metal slat to form a circuit. The mechanically shaped electrical interconnection may comprise a pattern metal slat to increase its mechanical conformation.

The solar cell chain may comprise a second mechanically shaped electrical interconnection and a third solar cell that has a front surface for being illuminated by light, a rear surface, and an electrically conductive rear surface metallization pattern placed on the rear surface. The second and third solar cells are positioned with an edge of the rear surface of the third solar cell superimposing an edge of the front surface of the second silicon solar cell. The mechanically shaped electrical interconnection joins a portion of the front surface of the second solar cell that is hidden by the third solar cell and joins a portion of the rear surface of the third solar cell to electrically connect the second and third cells solar in series.

* *

The interconnection may be between a metallization pattern on the front surface of the second solar cell and a metallization pattern on the rear surface of the third solar cell, for example. The mechanically shaped electrical interconnection can be attached to solar cells with electrically conductive junctions made by any of the methods outlined above, for example. Electrically conductive joints can interconnect fingers of a front surface metallization pattern of the second solar cell to carry out the current pick-up function of a busbar. A front surface metallization pattern in the solar cell may therefore lack any busbar.

A concentration solar energy collector can comprise the solar cell chain of any of the above variations and one or more optical elements arranged to concentrate the solar radiation on the chain.

In another aspect, a solar energy receiver comprises a substrate, a thermally conductive encapsulating layer that adheres to the substrate, a chain of solar cells placed in the thermally conductive encapsulating layer, a transparent encapsulating layer placed in the solar cell chain, and a transparent top sheet placed in the transparent encapsulating layer. The thermally conductive encapsulating layer comprises pigments. The solar cells may be, for example, any of the variations of silicon solar cells summarized above or any of the variations of the subsequent contact silicon solar cells described below, or solar cells configured similarly to any of those variations but using another different material system or in addition to silicon.

The thermally conductive encapsulating layer may reflect a substantial portion of the solar radiation incident thereon. In such variations, the thermally conductive encapsulating layer may be white, for example. In addition, in such variations, the solar cells may be HIT solar cells, with the reflective encapsulating layer accommodated to reflect towards the solar cell of

HIT the radiation that passes without absorbing through the HIT cell to the reflective layer. Alternatively, the thermally conductive encapsulating layer can absorb a substantial portion of solar radiation incident thereon. In such variations, the thermally conductive encapsulating layer may be black, for example. The transparent top sheet may have a humidity transmission rate of less than or equal to about 0.01 grams per meter-day, for example. The solar cell chain may comprise a plurality of solar cells accommodated with adjacent solar cell ends superimposing on a tejamanil pattern.

In another aspect, a rear contact silicon solar cell comprises a front surface to be illuminated by light, a rear surface, one or more contacts n on the rear surface that electrically contact a type n conductivity side of a diode junction of silicon, one or more contacts p on the rear surface that electrically contact a p-type conductivity side of the silicon diode junction, and one or more electrically conductive paths. The electrically conductive path passes through the solar cell from the rear surface to the front surface to provide, near one edge of the front surface, one or more electrical connections to any of the contacts po contacts n.

The front and rear surfaces may have corresponding rectangular or substantially corresponding shapes.

0 rectangles defined by two long sides positioned opposite and two short sides positioned opposite, with upper ends of the tracks arranged along a long side of the front surface. In some of such variations, the contacts n comprise a plurality of fingers n arranged side by side and running parallel to the short sides of the rear surface, the contacts ρ comprise a plurality of fingers p arranged side by side and running parallel to the short sides of the back surface, and fingers n and fingers p are interdigitated.

In other variations, the contacts n comprise a plurality of fingers n arranged side by side and running parallel between them at an angle to the short sides of the back surface such that the opposite ends of each finger n are offset in a direction parallel to the long sides for a distance equal to a distance between the fingers n, the contacts p comprise a plurality of fingers p arranged side by side and running parallel therebetween at an angle to the short sides of the rear surface such that the opposite ends of each finger p are offset in a parallel direction at the long sides for a distance equal to a distance between the fingers p, and the fingers n and the fingers p are interdigitated.

In other variations, the upper ends of the tracks may be accommodated along a short side of the front surface, and fingers n and fingers p may be similarly configured as summarized above except that they run parallel to, or in An angle with respect to the long sides of the back surface.

In still other variations, the rear contact solar cell can be substantially square, with tracks and fingers arranged similarly as summarized above and running parallel to, or at an angle to, a pair of sides of the solar cell .

In any of the above variations, the rear contact solar cell may comprise a busbar or a plurality of contact pads on the front surface that electrically interconnect the upper ends of the tracks.

A concentrating solar energy collector may comprise the solar cell which subsequent contact of any of the above variations and one or more optical elements arranged to concentrate the solar radiation on the solar cell.

In another aspect, a solar cell chain comprises a first rear contact silicon solar cell comprising a front surface to be illuminated by the light, a rear surface, one or more contacts n on the rear surface that electrically contact a side of type n conductivity of a diode junction, one or more contacts p on the back surface that electrically contact a p-type conductivity side of the diode junction, and a second rear contact silicon solar cell comprising a front surface made illuminated by the light, a rear surface, one or more contacts n on the rear surface that electrically contact a type n conductivity side of a diode junction, and one or more contacts p on the back surface that electrically contact a p-type conductivity side of the diode junction. The first and second rear contact silicon solar cells are positioned with an edge of the rear surface of the second rear contact silicon solar cell superimposing on an edge of the front surface of the first rear contact silicon solar cell and They are electrically connected in series.

The rear contact silicon solar cells can be, for example, from any of the variations of rear contact silicon solar cells summarized above.

In some variations, the first rear contact silicon solar cell comprises one or more paths

I »* electrically conductive that pass through the solar cell from its rear surface to its front surface to electrically interconnect any of the contacts by the contacts n of the first silicon solar cell of subsequent contact to the contacts of opposite polarity in the rear surface of the second silicon solar cell of rear contact. The upper ends of the conduction tracks can be located, for example, in a region of the front surface of the first rear contact silicon solar cell overlapping by the second rear contact silicon solar cell. The conduction paths can be electrically connected to the contacts on the rear surface of the second silicon solar cell by one or more electrically conductive junctions between the front surface of the first rear contact silicon solar cell and the rear surface of the second rear contact silicon solar cell. Electrically conductive junctions can be made by any of the methods outlined above, for example. The first rear contact silicon solar cell may optionally comprise a busbar or a plurality of contact pads on its front surface that electrically interconnect the upper ends of the tracks with each other, and that are connected

4 electrically to the contacts on the rear surface of the second solar contact silicon solar cell by said one or more electrically conductive joints.

In other variations, a mechanically shaped electrical interconnection electrically connects any of the contacts or contacts n on the rear surface of the first silicon solar cell of subsequent contact to the electrical contacts of opposite polarity on the rear surface of the second solar cell of rear contact silicon. The mechanically shaped electrical interconnection can be attached to solar cells with electrically conductive junctions made by any of the methods outlined above, for example.

A concentration solar energy collector may comprise the solar cell chain of any of the variations described above and one or more optical elements arranged to concentrate solar radiation on the solar cell.

In another aspect, a solar energy receiver comprises a substrate, and a series connected chain of two or more solar cells placed in the substrate with adjacent solar cell ends superimposing on a tejamanil pattern. The linear coefficient of thermal exoansion of the solar cells differs from that of the substrate in a

<td>higher value</td><td>or</td><td>same</td><td>what</td><td>approximately</td><td>5 x</td><td> 10”6,</td><td>or</td><td>in</td><td>a</td>

<td>higher value</td><td>or</td><td>same</td><td>what</td><td>approximately</td><td>10 x</td><td> 10“6,</td><td>or</td><td>in</td><td>a</td>

<td>higher value</td><td>or</td><td>same</td><td>what</td><td>approximately</td><td>15 x</td><td> 10~AND,</td><td>or</td><td>in</td><td>a</td>

value greater than or equal to approximately 20 χ IO-6.

Solar cells can be silicon solar cells, for example. Solar cells may be, for example, any of the variations of silicon solar cells summarized above, including variations of HIT solar cells and subsequent contact silicon cells, or solar cells configured similarly to any of those variations but using another system of different material or in addition to silicon.

The adjacent overlapping pairs of solar cells in the chain may be connected in series in a region where they are superimposed by an electrically conductive junction between a front surface of one of the solar cells and a rear surface of the other solar cell.

Such electrically conductive junctions can be formed by any of the methods outlined above, for example. Alternatively, the adjacent overlapping pairs of solar cells may be electrically connected in series in a region where they overlap by a mechanically formed electrical interconnection between a front surface of one of the solar cells and a; .Λ ν

'Λί back surface of the other solar cell. Mechanically shaped electrical interconnections can be attached to solar cells with electrically conductive junctions made by any of the methods outlined above, for example.

The substrate can be a metal substrate, an example.

The substrate can be an aluminum substrate, for example.

In some variations, the metal substrate is linearly elongated, each of the solar cells is elongated 1, and the solar cell chain is arranged in a row along a long axis of the substrate with the long axes of the cells oriented solar perpendicular to the long axis of the substrate. In such variations, the solar cell chain may be a first solar cell chain, and the solar energy receiver may also comprise a second chain connected in series of two or more solar cells placed in the substrate with adjacent solar cell ends overlapping in a tejamanil pattern, and a mechanically shaped electrical interconnection that electrically connects the first and second series chains. The linear coefficient of thermal expansion of solar cells in the second chain may also differ from that of the substrate by a value greater than or equal to approximately 5 χ 10 Ό, or in a

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Second chain can be joined with each other or otherwise interconnected as summarized above for the first chain, for example.

A concentration solar energy collector may comprise the solar energy receiver of any of the variations outlined above and one or more optical elements arranged to concentrate the solar radiation on the receiver.

In another aspect, a method of laminating solar cells to a substrate comprises accommodating a plurality of solar cells to form a series connected chain of solar cells with adjacent solar cell ends superimposing on a tile pattern, placing the solar cell chain in a stack of layers in the substrate, and apply a pressure no greater than about 0.6 atmospheres to force the stack of layers and the substrate together. The pressure can be, for example, less than or equal to about 0.4 atmospheres. The pressure can be, for example, between about 0.2 and 0.6 atmospheres. The ,

method may comprise heating the substrate, the layer stack, or the substrate and the layer stack to a temperature between about 130cC and 160 ° C while the pressure is applied. This method can be used with any of the variations of the solar cells, and any of the variations of the chains of superimposed solar cells connected in series, summarized above.

In another aspect, a method of preparing a solar cell chain comprises accommodating a plurality of solar cells with adjacent solar cell ends superimposing in a tejamanil manner and with an uncured electrically conductive epoxy placed between the superimposed portions of adjacent solar cells. in selected locations to connect the solar cells in series. The method also comprises applying a pressure to force the superimposed ends of the solar cells against each other while raising a temperature of the solar cells to cure the electrically conductive epoxy to form electrically conductive junctions between the solar cells. In some variations, after the electrically conductive epoxy is cured, the solar cell chain is placed in a stack of layers on a substrate that is then laminated on the substrate. In other variations, the solar cell chain is placed in a pile of layers on a substrate ♦% Vs 'Μ' * r

......... ·*<

before the electrically conductive epoxy is cured.

Then, the stack is laminated in the substrate. The electrically conductive epoxy is cured (under pressure) during the lamination process. This method can be used with any of the solar cell variations summarized above.

In any of the superimposed solar cell chains summarized above, the amount of overlap between adjacent solar cells may vary along the chain such that the size of the area of the front surface of each solar cell that is not superimposed by a Adjacent cell varies across the chain in a way that fits with the electrical performance of solar cells. For example, the different sizes of illuminated area (that is, not superimposed) for each solar cell can be selected to compensate for the inherent performance differences between the cells to thereby adjust with the current output for each cell when they are under equal illumination.

Any of the superimposed solar cell chains summarized above can be positioned for operation in a solar energy collector with the chain oriented such that for each solar cell having a portion of its front surface superimposed by another solar cell, the

0 Overlapping front surface portion is closer to the Earth's equator than the uncovered front surface portion. With the chain in this orientation, the exposed edges of the upper superimposed solar cells are oriented away from the Earth's equator.

Any of the variations of silicon solar cells summarized above can be formed from an understanding, for example, mono-crystalline or polycrystalline silicon.

These and other embodiments, features and advantages of the present invention will become more apparent to those skilled in the art when taken with reference to the following more detailed description of the invention in conjunction with the accompanying drawings that are first briefly described.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure IA shows a schematic diagram of an exemplary front surface metallization pattern for a solar cell.

Figure IB shows a schematic diagram of an exemplary back surface metallization pattern that can be used, for example, for a solar cell having the front surface metallization pattern of the

Figure ΙΑ.

Figure 1C shows a schematic diagram of an exemplary back surface metallization pattern for a rear contact solar cell in which the contacts on both sides of the diode junction are made on the back surface and in which the paths pass to through the cell from the rear surface to the front surface to provide electrical connection at one edge of the front surface to one side of the diode junction.

Figure ID shows a pattern of met cl_L 1 Ξα-CÍOn ds exemplary front surface for a rear contact solar cell in which the tracks pass through the cell from the rear surface to the front surface to provide electrical connections from one side from the diode junction to a busbar along an edge of the front surface.

Figure 1E shows a perspective view of an exemplary rear contact solar cell employing the front surface and the exemplary back surface metallization patterns of Figure 1C and Figure

ID, respectively.

Figure 1F shows another exemplary back surface metallization pattern for a rear contact solar cell in which the contacts on both sides of

two The diode junction is made on the back surface and in which the tracks pass through the cell from the back surface to the front surface to provide electrical connection at one edge of the front surface to one side of the diode junction.

Figure 2 shows a fragmentary view schematically illustrating one end of a solar energy receiver comprising a string of solar cells connected in series arranged in a manner of superposition on a linearly elongated substrate. Each solar cell has the front surface metallization pattern illustrated in Figure IA.

Figure 3A shows a schematic cross-sectional diagram illustrating the superposition of adjacent solar cells in the solar cell chain shown in Figure 2.

Figure 3B shows a schematic cross-sectional diagram illustrating the superposition of adjacent rear contact solar cells, with an electrical interconnection between the rear surfaces of the superposition solar cells made with a flexible electrical interconnection.

Figure 4 shows a schematic diagram of an exemplary solar cell chain that includes a first group

3 of superimposed solar cells electrically connected to a second group of superimposed solar cells by means of a mechanically electrically conductive shaped interconnection.

Figure 5A shows a schematic diagram of the mechanically exemplary shaped interconnection used in the solar cell chain illustrated in the

Figure 4

Figure 5B shows a schematic diagram of another mechanically shaped interconnection that can be used, for example, instead of the interconnection shown in Figure 5A.

Figures 6A-6C show schematic cross-sectional diagrams illustrating additional examples of series connected chains of overlapping solar cells.

Figures 7A and 7B show front and rear views, respectively, of another exemplary series connected chain of superimposed solar cells.

Figures 8A and 8B show front and rear views, respectively, of another exemplary series connected chain of superimposed solar cells.

Figure 9 shows a rear view of another chain connected in exemplary series of superimposed solar cells.

Figure 10 shows a fragmentary schematic diagram of an exemplary lamination stack, comprising solar cells, placed in and adhering to a substrate.

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of tejamanil as described in this specification.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description should be read with reference to the drawings, in which the identical reference numbers refer to similar elements throughout the different figures. The drawings, which are not necessarily to scale, represent selective modalities and are not intended to limit the scope of the invention. The detailed description illustrates by way of example, not by way of limitation, the principles of the invention. This description will clearly enable someone skilled in the art to make and use the invention, and describes various modalities, adaptations, variations, alternatives and uses of the invention, including what is currently believed to be the best way to carry out the invention.

As specification or this specification and the appended claims are used, the singular forms one, one, and / or include plural references unless the context clearly indicates otherwise. Also, the term parallel is intended in the sense of parallel or substantially parallel and encompasses minor deviations from parallel geometries rather than requiring that any parallel arrangement described herein be exactly parallel.

The term perpendicular is intended in the sense of perpendicular or substantially perpendicular and to encompass minor deviations from perpendicular geometries rather than requiring that any perpendicular arrangement described herein be exactly perpendicular.

This specification discloses high efficiency configurations for solar cell chains as well as solar cells (eg, photovoltaic cells), and electrically conductive interconnections for solar cells, which can be used in such chains. As described further below, the high efficiency configuration chains can be conveniently employed in concentrating solar energy collectors in which solar radiation is concentrated on the solar cells with reflectors, lenses, or other optical components. Such sensors can concentrate the light on the solar cells to provide lighting

6 greater than or equal to approximately seven suns, for example.

Figure IA shows a schematic diagram of an electrically conductive front surface metallization pattern on the front surface of an exemplary solar cell 10. The front surface of the solar cell 10 is rectangular or substantially rectangular. Other forms may also be used, as appropriate. The front surface metallization pattern includes a busbar 15 positioned adjacent to the edge of one of the long sides of the solar cell 10 and running parallel to the long sides by substantially the length of the long sides, and fingers 20 joined perpendicularly to the busbar and running parallel between them and with respect to the short sides of the solar cell 10 by substantially the length of the short sides.

The solar cell 10 comprises a semiconductor diode structure in which the front surface metallization pattern is placed. A back surface metallization pattern is placed on a rear surface of the solar cell 10 as shown, for example, in Figure

IB and described later. The semiconductor structure may be, for example, a conventional crystalline silicon diode structure comprising an np junction, with the upper semiconductor layer on which the

I »*

7 front surface metallization being, for example, of conductivity type no type p. Any other suitable semiconductor diode structure can also be used in any other suitable material system,

Referring now to Figure IB, an electrically conductive back surface metallization pattern on the rear surface of the solar cell 10 comprises the rear contact 25, and the rear contact pad 30 positioned adjacent the edge of one of the long sides of the solar cell 10 and running parallel to the long sides by substantially the length of the long sides. Figure IB shows the rear side of the solar cell 10 as if viewed through the front surface of the solar cell 10. As shown by a comparison of Figure IA and Figure IB, the rear contact pad 30 and The front surface busbar 15 is positioned along opposite long sides of the solar cell 10.

The front and rear surface metallization patterns in solar cell 10 provide electrical contacts to the semiconductor diode structure by means of which the electric current generated in solar cell 10, when illuminated by light, can provide a charge. external In addition, the metallization patterns of

8 is »* ► * illustrated front and rear surface allow two such solar cells 10 to be positioned in an overlapping geometry with their long sides parallel to each other and with the rear contact pad 30 of one of the solar cells overlapping and physically and electrically connected to the front surface collector parra 15 of the other solar cell. As described further below, this pattern can be continued, in a similar way roof tile, to construct a chain of two or more superimposed solar cells 10 electrically connected in series. Such an arrangement is referred to below as, for example, superimposed solar cells connected in series.

The exemplary solar cell 10 illustrated has a length of approximately 156 mm (mm), a width of approximately 26 mm, and therefore an aspect ratio (length of the short side / length of the long side) of approximately 1: 6 . Six such solar cells can be prepared in a standard 156 mm x 156 mm silicon wafer, then separated (diced) to provide the solar cells as illustrated. In other variations, eight solar cells 10 having dimensions of approximately 19.5 mm x 156 mm, and therefore an aspect ratio of approximately 1: 8, can be prepared at

9 from a standard silicon wafer. More generally, solar cells 10 have aspect ratios of, for example, about 1: 3 to 1:20 and can be prepared from standard size wafers or wafers of any other suitable dimension. As explained further below, solar cells that have long and narrow aspect ratios, as illustrated, can be conveniently employed in concentration photovoltaic solar energy collectors in which solar radiation is concentrated on the solar cells.

Referring again to Figure IA, in the example illustrated the front surface metallization pattern in solar cell 10 also comprises an optional branch conductor 40 running parallel to and apart from the busbar 15. The branch conductor 40 interconnects the fingers 20 to electrically derive cracks that can be formed between the busbar 15 and the bypass conductor 40. Such cracks, which can cut fingers 20 at locations near the busbar 15, may otherwise isolate regions of the solar cell 10 from the busbar 15. The bypass conductor provides an alternative electrical path between such cut fingers and the busbar

A branch conductor 40 may have a width, for example, less than or equal to approximately 1 mm, less than or equal to approximately 0.5 mm, or between approximately

0.05 mm and 0.5 mm. The example illustrated shows a branch conductor 40 positioned parallel to the busbar 15, extending over the entire length of the busbar, and interconnecting each finger 20. This arrangement may be preferred, but not required. If present, the bypass conductor does not need to run parallel to the busbar and does not need to extend the entire length of the busbar. In addition, a bypass conductor interconnects at least two fingers, but does not need to interconnect all fingers. Two or more short branch conductors can be used instead of a longer branch conductor, for example. Any suitable arrangement of branch conductors can be used. The use of such shunt conductors is described in greater detail in the Patent Application document of the

United States Serial No. 13 / 371,790, entitled Solar

Cell With Metallization Compensating For Or Preventing

Cracking, (Solar Cell With Metallization That Compensates For Or

Prevents Cracking), and filed on February 13

2012, which is incorporated in this document by reference in its entirety.

The exemplary front surface metallization pattern of Figure IA also includes an optional end conductor 42 that interconnects the fingers 20 at their far ends, opposite the busbar 15. The width of the conductor 42 may be approximately the same as that of One finger 20, for example. The conductor 42 interconnects the fingers to electrically derive cracks that can be formed between the branch conductor 40 and the conductor 42, and thus provides a current path to the busbar 15 for regions of the solar cell 10 that otherwise They could be electrically insulated by such cracks.

The busbar 15, fingers 20, bypass conductor 40 (if present), and the end conductor (if present) of the front surface metallization pattern can be formed, for example, from silver paste which is conventionally used for such purposes and deposited, for example, by conventional stamping methods.

Alternatively, these characteristics can be formed from electroplated copper. Any other suitable material and process can also be used. The busbar 15 may have a width perpendicular to its long axis of, for example, less than or equal to about 3 mm, and in the example illustrated it has a width of approximately 1.5 mm. The fingers 20 may be wide, for example, from about 10 micrometers to 100 mierometers.

In the example illustrated, the front surface metallization pattern includes approximately 125 fingers evenly spaced along the length of ~ 154 mm of the busbar 15. Other variations may employ, for example, less than about 125, approximately 150, approximately 175, approximately

200, about 225, about 125 to about 225, or more than about 225 fingers evenly spaced along a busbar 15 of about the same length 154 mm. Generally, the width of the busbar and the width, number, and spacing of the fingers can be varied depending on the intensity of the solar radiation to be concentrated in the solar cell. Generally, higher concentrations of solar radiation on the solar cell require more fingers and / or wider fingers to accommodate the resulting higher current generated in the solar cell. In some variations, the fingers may have widths that are larger near the busbar than they are away from the busbar.

I »*

Referring again to the exemplary back surface metallization pattern in Figure IB, the rear contact 25 can be a conventionally deposited aluminum contact, for example, and can substantially cover the rear surface of the solar cell 10.

Alternatively, the rear contact 25 may leave islands or other portions of the rear surface of the solar cell 10 unmetallized. As yet another alternative, the rear contact 25 may comprise fingers similar to those in the front surface metallization pattern, which run parallel to each other and to the short sides of the solar cell 10 by substantially the length of the short sides. Any other suitable configuration can also be used for the rear contact 25. The rear contact pad 30 can be formed, for example, from silver paste conventionally used for such purposes and deposited, for example, by means of methods of stamping with conventional stenciling. Alternatively, the contact 25 and / or the rear contact pad 30 can be formed from electroplated copper. Any other material and process can also be used to form the rear contact 25 and the rear contact pad 30. The contact pad 30 having a width perpendicular to its long axis of, for example, less than or equal to about 3 mm, and in the example illustrated it has a width of about 2 mm. The rear contact pad 30 may have a width, for example, that is adjusted or adjusted approximately with the width of the front busbar 15. In such cases, the rear contact pad 30 may have a width, for example, about 1 to 3 times the width of the busbar.

15.

The solar cells 10 can be intrinsic thin layer silicon solar cells (HIT,

Heterojunction with Intrinsic Thin Layer). In such cases, HIT cells may employ, for example, the front surface metallization patterns described above with respect to Figure IA or any variation of those front surface metallization patterns described herein. HIT cells may employ, for example, the back surface metallization patterns described above with respect to Figure IB or any variation of those back surface metallization patterns described herein. The back surface metallization pattern of the HIT cell may comprise fingers (eg, silver fingers) similar to those in the pattern of. front surface metallization of Figure IA. In such cases, the fingers of the back surface metallization pattern may be placed in a layer of transparent conductive oxide (TCO,

Transparent Conducting Oxide), which in turn is placed on the rear surface of the semiconductor diode structure. Alternatively, the back surface metallization pattern for HIT cells may comprise a thin layer of copper placed in a TCO layer, which in turn is placed on a rear surface of the semiconductor diode structure. The copper layer can be deposited by means of electroplating, for example. The TCO in this variation or the previous one may be of or comprise indium tin oxide, for example. Any other suitable back surface metallization pattern can also be used.

For HIT cells that are used in solar cell chains as described herein, a thin-layer copper back surface metallization pattern can handle high current density with low resistance and therefore results in loss. I¿R low in the back contact. Light that passes without being absorbed through the HIT cell is generally absorbed by the copper layer, however, this leads to optical loss. HIT cells in which the metallization pattern of

6 Back surface comprises fingers deposited in a TCO layer can be positioned with their back surfaces on or above a reflection surface, such as a white surface. The light that passes without being absorbed through the HIT cell can be reflected in this way to the HIT cell, passing the fingers and through the TCO, to be absorbed in the HIT cell and generate additional current. Loss I2R on the fingers may be greater than for the variation of back surface metallization of thin copper layer, however. The choice of the back surface metallization pattern generally depends on which pattern performs best when the HIT cells are illuminated at a desired level of concentration (eg, at one greater than or equal to approximately seven suns).

Referring now to Figure 2, an exemplary solar energy receiver 45 comprises a series of solar cells connected in series 10 arranged in a superimposed manner on a linearly elongated substrate 50. Each solar cell 10 in the solar energy receiver 45 has the Front and back surface metallization patterns illustrated in Figures IA and IB, respectively. The

Figure 3A shows a cross-sectional view illustrating the superposition of adjacent solar cells in the solar energy receiver 45. As shown in. Figure • ν ·

3Α, for each pair of superimposed solar cells the lower contact pad 30 of one solar cell is superimposed on the front surface busbar 15 of the other solar cell. The front surface busbar 15 at one end of the chain and the lower contact pad 30 exposed at the other end of the chain can be used to electrically connect the chain to other electrical components as desired. In the example illustrated in Figure 2, bypass conductors 40 are hidden by overlapping portions of adjacent cells. Alternatively, solar cells comprising bypass conductors 40 may be superimposed in a similar manner to that shown in Figure 2 and the

Figure 3A without covering bypass conductors.

The front surface busbar 15 and the lower contact pad 30 of an overlapping pair of solar cells 10 can be joined together using any suitable electrically conductive bonding material. Suitable conductive bonding materials may include, for example, electrically conductive reflux welding, and electrically conductive adhesives. Suitable electrically conductive adhesives may include, for example, interconnecting pastes, conductive films, and conductive films.

8 anisotropic available from Hitachi Chemical and other suppliers, as well as electrically conductive tapes available from Adhesives Research Inc., of Glen Rock

Pennsylvania, and other providers. Electrically conductive adhesives may also include conductive epoxies with silver or other conductive epoxies. In some variations, such electrically conductive adhesives can be selected, for example, to remain flexible over a temperature range between about -40 ° C and 115 ° C, have an electrical resistivity less than or equal to about 0.04 ohm centimeters, exhibit Elongation at break greater than or equal to approximately 20%, have a viscosity removed, or have any combination of the above characteristics.

The illustration in Figure 3A labels the front busbars 15 with a minus sign (-), and the lower contact pads 30 with a plus sign (+), to indicate electrical contact with the conductivity layers type n and type p in the solar cell, respectively. This labeling is not intended to be limiting. As noted above, solar cells can have any suitable diode structure.

Y

Referring again to Figure 2, the substrate 50 of the solar energy receiver 45 may be, for example, an aluminum or other metal substrate, a glass substrate, or a substrate formed from any other suitable material. The solar cells 10 can be attached to the substrate 50 in any suitable manner. For example, solar cells 10 can be laminated to an aluminum or other metal substrate 50 with interference adhesive, encapsulating layers, and / or electrically insulating layers placed between solar cells 10 and the surface of the metal substrate.

The substrate 50 may optionally comprise channels through which a liquid can be flowed to extract heat from the solar energy receiver 45 and thereby cool the solar cells 10, in which case the substrate 50 may preferably be a substrate of extruded metal The solar energy receiver 45 may employ, for example, delamination structures, substrate configurations, and other receiver components or features as disclosed in US Patent Application Document Serial No. 12 / 622,416, entitled

Receiver for Concentrating Solar Photovoltaic-Thermal

System, (Receiver to Concentrate Solar Thermal Photovoltaic System), and presented on November 19, 2009, which is incorporated herein by reference in its entirety * *. Although in the example illustrated the substrate 50 is linearly elongated, any other suitable form for the substrate 50 can also be used.

Receiver 45 may include only one row of solar cells that run along its length, as shown in Figure 2. Alternatively, receiver 45 may include two or more parallel rows of solar cells that run along its length. length.

The superimposed series connected solar cell chains as disclosed herein, and linearly elongated receivers that include such chains, can be used, for example, in solar energy collectors that concentrate solar radiation in a linear focus along of the length of the receiver, parallel to the solar cell chain. Concentration solar energy collectors that can conveniently employ superimposed series connected solar cell chains as disclosed herein may include, for example, solar energy collectors disclosed in the US Patent Application document. Serial number

12 / 781,706, entitled Concentrating Solar Energy Collector, and filed on May 17, 2010, and solar energy collectors disclosed in U.S. Patent Application Document No. Series 13 / 740,770, entitled

Concentrating Solar Energy Collector, (Energy Collector

Solar Concentration), and presented on January 14, 2013.

Each of these patent applications is incorporated herein by reference in its entirety. Such concentration solar energy collectors can, for example, use long narrow flat mirrors arranged to approximate a parabolic channel that concentrates solar radiation in a linear focus on the receiver.

Referring again to Figures IA and IB, although the examples illustrated show the front busbar 15 and the rear contact pad each extending substantially along the length of the long sides of the solar cell 10 with uniform widths, this may Be convenient but not required. For example, the front busbar 15 can be replaced by two or more discrete contact pads that can be accommodated, for example, in line between them along one side of the solar cell 10. Such discrete contact pads can interconnect optionally by means of thinner conductors that run between them. There may be a separate contact pad (eg, small) for each finger in the front surface metallization pattern, or each contact pad can be connected to

two Two or more fingers. The rear contact pad 30 can be similarly replaced by two or more discrete contact pads. The front busbar 15 can be continuous as shown in Figure IA, and the rear contact pad 30 formed of discrete contact pads, has just been described.

Alternatively, the front busbar 15 can be formed from discrete contact pads, and the rear contact pad 30 formed as shown in Figure IB. As yet another alternative, both the front busbar 15 and the rear contact pad 30 can be replaced by two or more discrete contact pads. In these variations, the current collection functions that would otherwise be carried out by means of the front busbar 15, the rear contact pad 30, or by the front busbar 15 and the rear contact pad 30 can be instead carry out, or partially carry out, the conductive material that is used to join two solar cells 10 with one another in the superimposed configuration described above.

Although Figure IB and Figure 3A show the.

rear contact pad 30 located adjacent to a long edge of the rear surface of the solar cell 10,

3 The contact pad 30 may have any suitable location on the rear surface of the solar cell. For example, Figures 6A-6C, 7B, and 8B, described further below, show exemplary solar cells 10 each of which has a contact pad 30 located near the center of the rear surface of the solar cell and which runs parallel to the long axis of the solar cell.

In addition, the solar cell 10 may lack the front busbar 15 and include only fingers 20 in the front surface metallization pattern, or lack the contact pad 30 and only include the contact 25 in the rear surface metallization pattern , or lack the front busbar 15 and lack the rear contact pad 30. In these variations also, the current collection functions that would otherwise be carried out by means of the front busbar 15, the rear contact pad 30, or the front busbar 15 and the rear contact pad 30 can be rather, it is carried out by the conductive material that is used to join all solar cells 10 with one another in the superimposed configuration described above.

Solar cells that lack the busbar 15, or that have the busbar 15 replaced by discrete contact pads, may include bypass conductor 40, or not include bypass conductor 40. If the busbar 15 is absent, the bypass conductor 40 may be accommodated to derive the cracks that form between the bypass conductor and the portion of the front surface metallization pattern that is conductively attached to the superposed solar cell.

Up to this point, solar cells 10 have been described as having front and rear surface metallization patterns that provide electrical contact to opposite sides of a diode junction. Alternatively, solar cells 10 may be rear contact solar cells in which a set of contacts on the rear surface of the solar cell makes electrically contact with one side of the diode junction, and another set of contacts on the rear surface of The solar cell makes electrically contact with the other side of the diode junction. When such solar cells are deployed in a conventional manner, generally no electrical contact is made on the front surface of the solar cells. This rear contact geometry conveniently increases the amount of light incident on the active portions of the solar cell

5 by removing the front surface metallization that would block the light. Such rear contact solar cells are available, for example, from SunPower Inc.

When used in chains in a solar cell tejamanil manner as described herein, such a rear contact solar cell may also include conduction paths that pass through the solar cell from its rear surface to its front surface. provide, at one edge of the front surface, one or more electrical connections to one side of the diode junction. When the solar cell is arranged in a tejamanil manner with a similarly configured solar cell adjacent, the front surface electrical connections at the edge of a cell overlap with and can be electrically connected to back surface contacts in the other cell to connect the two superimposed rear contact solar cells in series.

Figures 1C-1E schematically represent an exemplary complete rear contact solar cell 10 configured for use in a chain of superimposed solar cells (that is, in a tejamanil manner) connected in series. The exemplary back surface metallization pattern shown in Figure 1C and Figure 1E includes an optional p line that runs parallel and adjacent to the long side of

If • „, ί. · * The solar cell, a plurality of fingers p 24 connected to the line p and running parallel to the short sides of the solar cell, an optional line n 26 running parallel and adjacent to the other long side of the solar cell, and a plurality of fingers n 28 connected to the line n, which run parallel to the short sides of the solar cell, and interdigitated with the fingers p 24. The regions of the semiconductor structure below and in contact with fingers n and fingers p are correspondingly impurified with non-type type p to form a diode junction.

As seen in Figures 1C-1E, the exemplary rear contact solar cell 10 also includes connection paths 32 that pass through the solar cell 10 to provide electrical contact from line n 26 and fingers n 28 on the surface rear of the solar cell 10 to an optional busbar 24 that runs parallel and

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Rear of solar cells. As shown by a comparison of Figures 1C-1E, in the exemplary busbar 32 illustrated and line n 26 are positioned along the same long side of the solar cell, with line p

positioned along the opposite long side. The solar cells configured in this way can be positioned with the p 22 line on the back surface of a superimposed solar cell and electrically connected to the busbar on the front surface of an adjacent solar cell to connect the solar cells in series. In this arrangement, the busbar 34 is covered by an active portion of the superimposed solar cell. Therefore, there is no exposed front surface metallization that blocks the light from the active regions of the solar cell.

Alternatively, the polarities n and er in the above description can be exchanged so that the tracks 32 provide electrical contact from the contacts p on the rear surface of the solar cell 10 to the busbar 34 on the front surface. The solar cells configured in this way can be positioned with the line n on the rear surface of a superimposed solar cell and electrically connected to the busbar on the front surface of an adjacent solar cell to connect the two solar cells in series.

Although the examples illustrated show a path for each finger on the back surface to be electrically connected to the front surface, there may be more or less paths than fingers as long as the fingers by * iS

8 connect to the front surface are interconnected on the rear surface so that each is electrically connected to one or more tracks.

Although the busbar 34 is shown as substantially extending the entire length of the long sides of the solar cell 10 with uniform width, this may be convenient but not required. For example, the busbar 34 can be replaced by two or more discrete contact pads which can be accommodated, for example, in line with one another along one side of the solar cell 10. Such discrete contact pads can optionally be interconnected by thin conductors running between them. There may be a separate contact pad (eg, small) on the front surface for each track, or each contact pad may be connected to two or more tracks. Busbar 34 may also be absent. Line p 22 and / or line n 26 can be similarly replaced by two or more discrete contact pads, or they may be absent.

Some variations lack a busbar 34 at the front surface end of the tracks, or lack an interconnecting conductor such as a line or a line n at the rear surface end of the tracks, or lack a busbar 34 at the upper surface end of the tracks and also lack an interconnecting conductor at the rear surface end of the tracks. In variations in which the busbar 34, line p 22, and / or line n 26 are formed from discrete contact pads or are absent, the current pick-up functions that would otherwise be carried out by By means of these characteristics, they can be carried out rather, or partially carried out, by means of conductive material than used to jointly join two solar cells in the overlay configuration described above.

To shorten the current path between the rear contact solar cells superimposed through the paths described above, it may be desirable to configure and / or accommodate the solar cells so that each path is aligned at one end with the end of a finger (nop) on the back surface of a solar cell and aligned at its other end with the end of a finger (ρ on) of opposite polarity on the back surface of an adjacent superimposed solar cell. With the fingers configured as shown in Figure 1C, the tracks can be aligned in this way by positioning the superimposed solar cells in such a way that one moves with respect to the other along its long overlapping sides by a distance equal to the passage between the fingers.

Alternatively, the fingers may be configured as shown in Figure 1F, for example, such that they extend at an angle through the rear surface of the solar cell such that the opposite ends of each finger are offset to along the long sides of the solar cell for a distance equal to the passage between the fingers.

The solar cells configured in this manner can be superimposed with their short sides flush to provide the desired track alignment with the fingers on the superimposed solar cells. Although Figure 1F shows the back surface metallization pattern that includes the p 22 line and the n26 line, any or arribas may be absent.

The tracks 32 can therefore interconnect two solar cells of back contact overlapping finger to finger, finger

<td>to line</td><td>(eg, bar</td><td>collector line</td><td>p, o</td><td>line η),</td><td>or line</td>

<td>to line,</td><td>for example.</td><td></td><td></td><td></td><td></td>

<td>The</td><td>formation of</td><td>tracks 32 are</td><td>may</td><td>to integrate</td><td>in the</td>

<td>processes</td><td>of fabric</td><td>tion convinces</td><td>them</td><td>for the</td><td>cells</td>

Full rear contact solar. The holes for the tracks can be formed, for example, by means of conventional laser drilling and can be filled, for example, with any suitable conventional conductive material deposited by means of any suitable conventional method. The conductive material may be an electroplated metal or a printed conductive metal paste, for example.

The rear contact solar cells can also be used in chains of superimposed solar cells connected in series without the use of the paths described above. Referring to the cross-sectional view of Figure 3B, for example, two such superimposed rear contact solar cells can be electrically connected in series by means of a mechanically shaped electrical interconnection 90 that interconnects a rear contact in one of the solar cells and a subsequent contact of opposite polarity in the other solar cell.

The chains of superimposed solar cells connected in series disclosed in this document, and linearly elongated receivers that include such chains, must operate more efficiently than conventional accommodations, particularly under concentrated lighting. In some variations, the superimposed solar cell chains disclosed in this document may provide, for example, 2. 15% more output energy than conventionally arranged solar cell chains.

Dipping a wafer to provide solar cells that have smaller areas reduces the current I generated in the solar cells and can thus reduce energy losses I2R resulting from internal R resistance to solar cells and resistance in connections between solar cells in a chain. However, conventional solar cell chains connected in series require spaces between adjacent solar cells. For a chain of a given physical length, the number of such spaces increases as the solar cells become shorter. Each space reduces the energy generated by the chain, thereby overcoming, at least partially, the advantage that could otherwise result from using solar cells from smaller areas. In addition, the loss of energy resulting from the spaces increases when such a conventional chain is used in a concentration solar energy collector.

In contrast, the conventional solar cell chains, the series of superimposed connected solar cell chains disclosed in this document do not have spaces between solar cells. Solar cells in such chains can thus be diced into smaller areas to reduce IR losses without accumulating energy losses due to spaces. For example, you can

3 «<*, ** it is convenient to use solar cells that have a longer side that has a length that encompasses a standard wafer, as in solar cells 10 that are represented in the different figures in this document, because such solar cells they can be oriented with their longer sides perpendicular to the long axis of the chain to provide a wider focal region in a solar energy collector of linear focus concentration. (Making the focal region wider, relaxes the tolerances on the optical elements in the concentration solar energy collector, and can facilitate the convenient use of flat mirrors). For conventional solar cell chains, the optimal length of the short side of the solar cells would then be determined, in part, by compensation between energy losses I2R and losses due to spaces between cells. For the superimposed solar cell chains disclosed in this document, the length of the short sides of the solar cells (and therefore the areas of the solar cells) can be selected to reduce IR losses to a desired level without Concern for losses due to spaces.

Conventional solar cells generally employ two or more parallel front surface busbars * *

VI that obscure the underlying portions of the solar cells and therefore reduce the energy generated by each solar cell. This problem is exacerbated by copper slats, generally wider than the busbars, which are used in conventional chains to electrically connect the front surface busbars of a solar cell to the rear surface contact of an adjacent solar cell in the chain. . The copper slats in such conventional chains generally run through the front surface of the solar cells, parallel to the chain and overlying the busbars. The energy losses resulting from the darkening by the busbars and the copper slats increase when such conventional solar cells are used in a concentration solar energy collector. In contrast, the solar cells disclosed in this document may only use a busbar on their front surfaces, as illustrated, or no busbar, and do not require copper slats running through the illuminated front surface of the solar cells. . In addition, in superimposed solar cell chains as disclosed herein, the front surface busbar in each solar cell, if present, can be hidden by the active surface area of an overlapping solar cell, except at one end.

5 of the chain. The solar cells and solar cell chains disclosed in this document can therefore significantly reduce losses due to the darkening of the underlying portions of the solar cells by front surface metallization, compared to conventional configurations.

A component of IR energy losses is due to the current paths through the fingers in the front surface metallization. In conventionally arranged solar cell chains, the busbars on the front surfaces of the solar cells are oriented parallel to the length of the chain, and the fingers are oriented perpendicularly to the length of the chain. The current within a solar cell in such a conventional chain flows primarily perpendicular to the length of the chain along the fingers to reach the busbars. The finger lengths required in such geometries can be long enough to result in significant I'R energy losses in the fingers. In contrast, the fingers on the front surface metallization of the solar cells disclosed herein are oriented parallel to the short sides of the solar cells and parallel to the length of the chain, and the current in a solar cell flows mainly parallel

6 to the length of the chain along the fingers. The lengths of the fingers required in this arrangement may be shorter than those required for conventional cells, thereby reducing energy losses.

Other component of energy losses I2R is due to the length of the current path between adjacent solar cells through conventional copper ribbon interconnections. The current paths between adjacent solar cells in the overlapping configurations disclosed herein may be shorter than in conventional arrangements, thereby reducing losses IZR.

The solar cell metallization patterns and / or superimposed cell geometries disclosed in this document can be conveniently used with crystalline silicon solar cells placed on a metal substrate, as in the receiver 4 5 of Figure 2, for example .

However, someone experienced in the field may find this surprising. If formed using conventional reflux welding, for example, the junction between the front surface busbar and the rear surface contact pad of solar cells superimposed on a chain as disclosed herein may be significantly more rigid than the connections. * *

Electrical VIs between adjacent solar cells that are provided by means of copper lath tabs in conventional solar cell chain tabs. Consequently, compared to the use of copper lath tabs, welding connections between adjacent solar cells in such a chain can provide significantly less strain relief to accommodate the mismatch between the thermal expansion coefficient (GTE,

Coefficient of Thermal Expansion) of the silicon solar cells and the metal substrate. That mismatch can be quite large. For example, crystalline silicon has a CTE of ~ 3 x 10-6, and aluminum has a CTE of - 23 χ 10-6. Anyone skilled in the art can therefore expect such superimposed silicon solar cell chains placed on a metal substrate to fail due to the silicon solar cell cracking. This expectation would be even stronger and for such superimposed solar cell chains used in a concentration solar energy collector in which they could cycle through larger temperature ranges, and therefore experience greater deformation due to expansion mismatch. thermal with the substrate, which is usually experienced in a non-concentration solar energy collector.

Contrary to such expectations, however, the inventors have determined that the superimposed silicon solar cell chains connected in series can be joined together with conventional reflux welding, attached to an aluminum or other metal substrate, and operate in Reliable way under concentrated solar radiation. Such chains may have a length, for example, greater than or equal to approximately 120 mm, greater than or equal to approximately

200 mm, greater than or equal to approximately 300 mm, greater than or equal to approximately 400 mm, greater than or equal to approximately 500 mm, or between approximately 120 mm and 500 mm.

In addition, the inventors have also determined that welding substitutes such as those described above, including electrically conductive tapes, conductive films, interconnecting pastes, conductive epoxies, eg silver conductive epoxies), and other similar conductive adhesives, for example, they can be used to join the solar cells with each other to form even longer chains of superimposed solar cells connected in series on a metal substrate. In such variations, the conductive bonding material that joins the overlapping cells together is selected to be mechanically shaped, whereby it is understood that the bonding material deforms elastically easily - as a spring. (Mechanical compliance is the inverse of stiffness). In particular, the conductive junctions between solar cells in such chains are selected to be more mechanically shaped than solar cells 10, and more mechanically shaped than conventional reflow solder connections that could otherwise be used between overlapping solar cells. . Such mechanically shaped conductive junctions between the superimposed solar cells deform without cracking, detaching from adjacent solar cells, or otherwise failing under the deformation resulting from the mismatch of thermal expansion between solar cells 10 and the substrate 50. The formed unions mechanically they can therefore provide tension relief to a chain of interconnected superimposed solar cells, thereby accommodating the mismatch of

CTE between solar cells 10 and substrate 50 and preventing the chain from failing. The difference between the CTE of the solar cell (eg, silicon) and the substrate can be, for example, greater than or equal to about 5 χ 10 ~6, greater than or equal to approximately 10 * 10 "6, greater than or equal to approximately 15 * 10-% or greater than or equal to approximately x 10 "°. Such superimposed silicon solar cell chains connected in series placed on a substrate with

Misaligned CTEs can have a length, for example, greater than or equal to approximately 1 meter, greater than or equal to approximately 2 meters, or greater than or equal to approximately meters.

Moreover, the inventors have developed mechanically shaped electrical interconnections that can be used to interconnect two or more chains of superimposed solar cells interconnected in series to form longer chains of solar cells connected in series. The resulting longer chains can be placed on a metal or other substrate and operate reliably under concentrated solar radiation. Referring now to the

Figure 4, an exemplary chain 55 of solar cells connected in series comprises a first group 60 of superimposed solar cells 10 connected in series that are electrically and physically connected to a second group 65 of superimposed solar cells 10 connected in series by means of an interconnection 70 electrically conductive mechanically shaped. Additional interconnections 70 are located at the ends of the chain 55 to allow additional groups of overlapping solar cells connected in series to any end of the chain 55 to extend the length of the chain. Alternatively, interconnections

0 which are located at the ends of a chain can be used to interconnect the chain to other electrical components or to an external load. Overlapping solar cells within groups 60 and 55 can be joined together with electrically conductive reflux welding or electrically conductive adhesives, as described above, or in any other suitable manner.

The spacing between adjacent ends of two groups of superimposed solar cells 10 connected in series interconnected with a mechanically shaped interconnection 70 may be, for example, less than or equal to approximately 0.2 mm, less than or equal to approximately 0.5 mm, less than or equal to approximately 1 mm, less than or equal to approximately 2 mm, less than or equal to approximately 3 mm, less than or equal to approximately 4 mm, or less than or equal to approximately 5 mm.

The variation of the mechanically shaped electrical interconnection shown in Figure 4 is also shown, in greater detail, in Figure 5A. Other s. vs x? .i, 3. c .i. or nd θ the mechanically shaped electrical interconnection 70 having similar characteristics is shown in Figure 5B.

Referring now to Figure 5A and Figure 5B as well as to Figure 4, the mechanically shaped electrical interconnections 70 * * are slat type and have a long and narrow aspect ratio with a length approximately equal to or greater than the length of the long sides of the solar cells 10. Each interconnection 70 comprises two sets of tongues positioned on an opposite side of the long axis of the interconnection. As shown in Figure 4, an interconnection 70 may be positioned between two superimposed solar cell chains connected in series with their tabs 7 5 on one side making electrical contact with the busbar 15 on the front surface of an end solar cell of a chain of superimposed solar cells, and with its tabs 75 on the other side making electrical contact with the contact pad rent on the back surface of an end cell of the other chain of overlapping solar cells. The tabs 75 may be attached to the busbar 15 or to the contact pad 30 with conventional electrically conductive welding, electrically conductive adhesives as described above, or by any other suitable method.

In the example of the. Figure 4, the interconnections 7 0 at the end of the chain 55 also each include a bypass diode socket 80 at one end, in addition to the tabs

75. Bypass diode 80 sockets provide points * *

SAW

3 of connection for bypass diodes. In the example illustrated, bypass diode 85 is configured to derive both groups of superimposed solar cells connected in series in the event that a solar cell in the chain 55 fails. Alternatively, the interconnections 70 having bypass diode sockets 80 can be used at any desired interval in a chain to derive one, two, or more groups of superimposed solar cells connected in series. The maximum number of solar cells that can be accommodated to be derived by means of a bypass diode is determined by the performance characteristics of the bypass diode. The bypass diodes to be configured to derive, for example, approximately 25 solar cells

10, which can be distributed in any desired number of groups connected in series of superimposed solar cells connected in series. For example, each bypass diode may be configured to derive approximately 25 solar cells, all of which are part of a single group of superimposed solar cells connected in series. Although in the example illustrated the bypass diode is connected to the chain with interconnections 70, alternative configurations can also be used. For example, bypass diodes can be connected to the chain by means of a

4 conductor (other than an interconnection 70) that is electrically connected to the lower metallization pattern of a solar cell, and by another conductor (other than an interconnection 70) that is electrically connected to a busbar on the front surface of another solar cell .

Such connections can be made to solar cells that do not

<td>they are at the end</td><td>from</td><td>a group of</td><td>cells</td><td>solar</td>

<td>connected overlays</td><td>in</td><td>series but more</td><td>all right</td><td>in some</td>

<td>Making reference</td><td colspan="2">now to figure</td><td>11, the</td><td>diode of</td>

bypass 85 can be mounted on a flexible circuit 87 comprising two physically separated electrical contacts 92 sandwiched between two insulation sheets. The insulation sheets are in pattern to expose adjacent regions of the two contacts to which the diode is attached to electrically interconnect the contacts, and to expose the regions 97 of the contacts allowing the flexible circuit to be electrically connected to derive a portion of The solar cell chain. Each of the contacts 92 has a shape or pattern to increase its mechanical compliance.

In particular, contacts 92 include narrow necks and oval-shaped regions that make the contacts very shaped. The contacts 92 can be formed, for example, from a metal strip (eg, copper) coated with

welding. Insulation sheets can be formed, for example, from a polyimide. The flexible circuit 87 may further comprise a lower adhesive layer by means of which it can be attached to a substrate that supports a chain of solar cells.

Referring again to Figure 4, Figure

5A, and Figure 5B, the interconnections 70 are mechanically shaped. In particular, they are more mechanically shaped than the solar cells 10 and more mechanically shaped than the weld connections between the busbar 15 and the rear contact pad 30 of the overlapping solar cells 10. The interconnections 70 may also be more mechanically shaped than the junctions between the overlapping solar cells formed from electrically conductive adhesives as described above. The interconnections 70 deform without cracking, detaching from adjacent solar cells, or otherwise failing under deformation resulting from the mismatch of thermal expansion between solar cells 10 and the substrate 50. The interconnections 70 can therefore provide tension relief to a chain of interconnected groups of overlapping solar cells, thereby accommodating the mismatch of thermal expansion between the solar cells and the substrate 50 and preventing

6 That the chain fails.

In the examples illustrated, each 7 0 interconnect is a metal strip (eg, copper) coated with solder having a shape or pattern to improve its mechanical conformity. In particular, the interconnection 70 illustrated in Figure 5A includes a central portion that is in the form of a series of two or more flattened ovals intertwined at its ends. Each flattened oval includes a pair of tabs 75 on opposite flattened sides of the oval, to make contact with the solar cells as described above. The flattened ovals make each interconnection very shaped (like springs) in parallel and perpendicular directions to the long axis of the interconnection. In the example illustrated, the metal strips that form the walls of the ovals have a width W1 of approximately

1.5 mm, but any suitable width can be used. The 7 0 interconnection illustrated in Figure 5B includes a series of slots that run along the center of the metal slat parallel to its long axis. The slots make the interconnection of this variation very shaped, too. The interconnections 70 can be formed from highly conductive materials such as copper, for example, and / or from materials such as Invar (a nickel-iron alloy) and Kovar (a nickel-cobalt alloy77)

If • „, ί. · * Iron) that have a low thermal expansion coefficient.

Each metal slat can be sandwiched between thin insulation sheets of material to form a flexible circuit, with pattern insulated sheets to expose portions of the metal slat (e.g., tabs 75) that are intended to make contact electric with solar cells. Insulation sheets can be formed from a polyimide, for example.

Any other material and configuration suitable for interconnections 70 that interconnect two chains connected in series of superimposed solar cells can also be used. For example, interconnections 70 may be similar or identical to any of the mechanically shaped interconnections 90 described below with respect to Figures 6A-6C, 7A, 7B, 8A, 8B or

9. Also, two or more 7 0 interconnections can be arranged in parallel in a similar manner as shown in the Figures

7A and 7B described below to interconnect two groups of superimposed solar cells connected in series.

Although the use of interconnections 70 was described above with respect to solar cells 10 including front surface busbars 15 and rear contact pads 30, such interconnections 70 can be used in combination with any of the variations of

<td>the solar cell</td><td>10 described</td><td>in this document.</td><td>In variations</td>

<td>that lack</td><td>the bars</td><td>collectors 15, the</td><td>pads of</td>

<td>pole contact</td><td>rior 30, or</td><td colspan="2">both, interconnections 70 are</td>

<td>can join</td><td>the cells</td><td>solar 10 utili</td><td>zando adhesives</td>

<td>electrically</td><td>conductive</td><td>as described</td><td>previously,</td>

<td>for example.</td><td></td><td></td><td></td>

Mechanically shaped electrical interconnections similar or identical to interconnections 70 can also be used between each solar cell in a chain of solar cells connected in series, or between each solar cell in a contiguous portion of three solar cells or more of the chain connected in solar cell series. As shown in Figures 6A-6C, 7A, 7B, 8A, 8B and 9, for example, each pair of solar cells 10 superimposed on a chain connected in series of superimposed solar cells can be physically and electrically connected by means of the mechanically shaped interconnections, each of which interconnects the metallization and frontal surface of a solar cell with the posterior surface metallization of an adjacent solar cell. Such chains differ from conventional tongue chains at least because the adjacent solar cells in the chains illustrated are superimposed, and because the locations in which the interconnections 90 are attached to the front surfaces of the solar cells 10 they can be hidden from the lighting by an overlapping solar cell. Mechanically shaped interconnections 90 can be attached to solar cells with, for example, conventional electrically conductive welding, electrically conductive adhesives, adhesive films, or adhesive tapes as described above, or by any other suitable method.

The interconnections 90 are mechanically shaped.

In particular, they are more mechanically shaped than the solar cells 10 and more mechanically shaped than the weld connections between the busbar 15 and the rear contact pad 30 of the overlapping solar cells 10. The interconnections 90 may also be more mechanically shaped than the joints between superimposed solar cells formed from electrically conductive adhesives as described above.

The interconnections 90 deform without cracking, detaching from adjacent solar cells, or otherwise failing under deformation resulting from thermal expansion mismatch between solar cells 10 and a substrate to which they are attached. The interconnections 90 can therefore provide tension relief to a chain of interconnected groups of overlapping solar cells, thereby accommodating the mismatch of thermal expansion between the * *

0 10 solar cells and a substrate and preventing the chain from failing.

The interconnections 90 can be formed, for example, from highly conductive materials such as copper, an example, and / or from materials such as

Invar and Kovar that have a low thermal expansion coefficient. The interconnections 90 may be of or comprise weld coated copper slats, for example.

Alternatively, the SO interconnections may be or comprise copper slats interspersed between polyimide layers (eg, Kapton films) or other insulating layers, with the layers interspersed in pattern to expose the copper slat at the locations that are They will join solar cells. Any other material and configuration may be used for interconnections 90, in addition to those disclosed in this document.

Figures 6A-6C show exemplary cross-sectional views illustrating the interconnection of a chain of superimposed solar cells 10 with mechanically shaped electrical interconnections. One is illustrated in these examples, the interconnections 90 may have a flat cross-section profile (Figure 6A), a folded cross-section profile (Figure 6B), or a curved cross-section profile (Figure 6C). Any other suitable cross section profile can also be used. Bent or curved cross section profiles can increase mechanical compliance, compared to a flat cross section profile.

In the examples illustrated in Figures 6A-6C and in subsequent figures, the rear contact pad is located away from the edge of the solar cell 10, near the middle of the rear surface. This is not required.

The contact pad 30 may be positioned in any suitable location on the rear surface of the solar cell. For example, the contact pad 30 may be positioned adjacent to the superimposed edge of the solar cell 10, as shown in Figure IB, or adjacent to the opposite edge of the overlapping edge.

Figures 7A and 7B show front and back views, respectively, of an exemplary chain of superimposed solar cells connected in series. As shown in these figures, two or more interconnections 90 may be arranged in parallel with each other to interconnect adjacent superimposed solar cells. In the example illustrated, the interconnections 90 are in the form of slats with their long shafts oriented perpendicular to the superimposed edges of adjacent solar cells. As another example (no parallel interconnections 90 may have the one shown), the shapes of two or more slats arranged in line between them with their long axes oriented parallel to the superimposed edges of adjacent solar cells.

Figures 8A and 8B show front and rear views, respectively, of another exemplary chain of superimposed solar cells connected in series. Figure 9 shows a rear view of yet another exemplary chain of superimposed solar cells connected in series. As shown in Figures 8A, 8B, and 9, the interconnections 90 may be in the form of slats oriented parallel to and extending along the length of the overlapping edges of adjacent solar cells.

The interconnections 90 copies that are illustrated in the

Figures 8A and 8B are similar or identical to the interconnections 70 illustrated in Figure 4 and Figure

5. In the variation illustrated in Figures 8A and 8B, each interconnection 90 includes two sets of tabs 75, with each set of tabs positioned on an opposite side of the long axis of the interconnection. Such interconnection 90 may be positioned between two superimposed solar cells with their tabs 75 on one side making electrical contact with the busbar 15 on the front surface of one of the solar cells, and with their tabs 75 on the other side making electrical contact with 30% contact pad

on the back surface of the other solar cell. Also as illustrated in Figures 8A and 8B, the interconnections may optionally include bypass diode sockets 80 that provide connection points for bypass diodes configured to derive one or more solar cells in the event that one of the solar cells fail.

The interconnections 90 copies illustrated in the

Figure 9 is in the form of rectangular slats in pattern with slits or openings 95 that increase its mechanical conformity. The interconnections 90 illustrated also include contact pads 100 to be attached to the solar cells. Such interconnections 90 may be, for example, or comprise copper slats interspersed between layers of polyimide (eg, Rapten films) or other insulating layers, with the layers interspersed in pattern to expose the copper slat at locations of contact pads 100.

Although the use of interconnections 90 was described above with respect to solar cells 10 including front surface busbars 15 and rear contact pads 30, such interconnections 90 can be used in combination with any of the solar cell variations 10 described in this document. In variations that * * lack busbars 15, rear contact pads 30, or both, interconnections 90 can be attached to solar cells 10 using electrically conductive adhesives as described above, for example.

Referring now to Figure 10, a chain of solar cells 10 can be placed on a substrate 50 in a rolling stack 105 that adheres to the substrate. The lamination row may comprise, for example, a thermally conductive encapsulating layer 110 placed between the solar cells and the substrate, a transparent encapsulating layer 115 placed in the thermally conductive encapsulating layer, and a transparent top sheet

120 placed in the transparent encapsulating layer 115. The solar cells 10 are generally placed within the transparent encapsulating layer 115 at its border with the thermally conductive encapsulating layer 110.

The thermally conductive encapsulating layer 110 comprises one or more materials that are selected to facilitate heat transfer from the solar cells 10 to the substrate 50 and / or to adhere the substrate 50, to the solar cells 10, and to the transparent encapsulating layer 115. The material in the encapsulating layer 110 may be selected to adhere to aluminum or aluminum based alloys, for example. The thermally conductive encapsulating layer 110

it can have a thickness, for example, of about 0.1 millimeters to 2.0 millimeters.

In the example illustrated, the thermally conductive encapsulating layer 110 comprises a first layer of thermally conductive adhesive 125, a dielectric layer

130, and a second layer of thermally conductive adhesive

135 The dielectric layer 130 generally melts at a temperature higher than the surrounding adhesive layers, and consequently provides a barrier to physical and electrical contact between the solar cells 10 and the substrate 50 that survives a lamination process, described below, by means from which the rolling stack 105 is attached to the substrate 50. The adhesive layer 125 may comprise, for example, one or more thermally conductive polycyclines and may have a thickness, for example, of about 0.1 millimeters to 2.0 millimeters. The dielectric layer 130 may comprise, for example, one or more fiuoropolymers. The fluoropolymers can be selected, for example, from the group that includes, but is not limited to, polyvinyl fluoride (PVF, Polyvinyl Fluoride}, polyvinylidene fluoride (PVDF,

Polyvinylidene Fluoride), ethylene tetrafiuoroethylene, and mixtures thereof. The dielectric layer I30 may have a thickness, for example, of about 0.1 millimeters to 2.0 millimeters. The adhesive layer 135 may comprise, by * *

6 For example, one or more thermally conductive polyolefins and can have a thickness, for example, of about 0.1 millimeters to 2.0 millimeters.

Any other material and configuration suitable for the thermally conductive encapsulating layer 110 and its component layers 125 may be used,

130, and 135 described above. For example, in some variations the dielectric layer 130 is absent. In such variations, the encapsulating layer 115 may be, for example, a single layer of thermally conductive polyolefin.

The only conductive encapsulating layer 110 may be substantially reflective of the incident solar radiation thereon. For example, the materials in the encapsulating layer 110 may include pigments that make the encapsulating layer 110 appear white. Such encapsulating layer

110 The reflector reduces the heat absorbed by the rolling stack 105, which can conveniently improve the efficiency with which solar cells 10 operate. In addition, if the solar cells 10 are HIT solar cells with back surface metallization comprising fingers, as described above, then such a reflective encapsulating layer can reflect the light that has passed without being absorbed through the return HIT solar cell. to the solar cell where it can be absorbed to generate additional current, increasing the efficiency with which the solar cells operate. Alternatively, the thermally conductive encapsulating layer 110 may be substantially absorbing the incident solar radiation thereon.

For example, the materials in the encapsulating layer 110 may include pigments that make the encapsulating layer

110 Look black Such an encapsulating absorbent layer 110 may increase the heat absorbed by the rolling stack 105 and subsequently transferred to the substrate 50, which may be convenient if the heat captured is commercially valuable.

Referring again to. the. Figure 10, the transparent encapsulating layer 115 may comprise, for example, a transparent polyolefin, a transparent polyimide, a mixture thereof, and may have a thickness, for example, of about 0.1 millimeters to 2.0 millimeters. Any other material and thickness suitable for the transparent encapsulating layer 115 can be used.

The transparent topsheet 120 may comprise, for example, one or more transparent fluoropolymers. The fluoropolymers can be selected, for example, from the group that includes, but is not limited to, polyvinyl fluoride (PVF), ethylene tetrafluoroethiene, and mixtures thereof. The transparent top sheet 120 can be selected to have a moisture transmission rate of less than or equal to about 0.01 grams / meter-day, for example. The transparent topsheet 120 may have a thickness, for example, of about 0.1 millimeters to 1.0 millimeters.

Any other material and thickness suitable for the transparent top sheet 120 can be used.

The solar cells 10 in the rolling stack 105 may be or comprise any of the solar cells that

<td>are disclosed in this</td><td>3 document, and</td><td>S Θ</td><td>they can</td><td>accommodate in</td>

<td>any of the</td><td>configurations</td><td>from</td><td>chains</td><td>of cells</td>

<td>solar overlays</td><td>connected in</td><td>Serie</td><td>That</td><td>report on</td>

this document. Any other suitable solar cell and chain configuration can also be placed in the rolling stack 105, however. For example, although the solar cells 10 in Figure 10 are shown as superimposed on a tile pattern, the solar cells placed in the stack 105 can be configured rather in a non-overlapping manner and with conventional tabs.

The layers of components of the rolling stack 105 can be positioned on a substrate 50 and then joined to the substrate 50 in a conventional rolling mill, for example, at an elevated temperature and with the application of directed pressure to force the rolling stack 105 and the substrate 50 so that they come together. During this lamination process, the temperature of the substrate 50 and / or the lamination stack 105 can be raised, for example, to between approximately 130 ° C and

160 ° C If the solar cells in the rolling stack 105 are configured in a non-overlapping manner, the pressure applied during the rolling process may be approximately 1.0 atmosphere, for example. The inventors have determined, however, that if the solar cells in the rolling stack 105 are configured in an overlapping manner, as described herein, for example, the maximum pressure applied during the rolling process may preferably be lower. or same as

<td>approximately</td><td> 0.6</td><td>atmospheres,</td><td>less</td><td>or</td><td>same</td><td>what</td>

<td>approximately</td><td> 0.5</td><td>atmospheres,</td><td>less</td><td>or</td><td>same</td><td>what</td>

<td>approximately</td><td> 0.4</td><td>atmospheres,</td><td>less</td><td>or</td><td>same</td><td>what</td>

approximately 0.3 atmospheres, or between approximately 0.2 atmospheres and 0.6 atmospheres.

In variations in which the superimposed solar cells are joined together with a conductive epoxy such as a conductive epoxy with silver, for example, it may be preferable to cure the epoxy while applying pressure to force the solar cells against each other. Curing the conductive junction under pressure in this way can reduce the thickness of the conductive junction, thereby reducing the current path between the solar cells and consequently reducing the losses I2R in the solar cell chain. In one approach, the conduction joints are cured under pressure to provide a series connected chain of superimposed solar cells before the chain is laminated to a substrate. In this approach, the conduction joints can be cured at a temperature of, for example, approximately 150 ° C to 180 ° C and under a pressure of, for example, approximately 0.1 atmospheres at 1.0 atmospheres, or approximately 0.1 to 0.5 atmospheres, or about 0.1 to

0.2 atmospheres In another approach, the conduction joints are cured under pressure during a lamination process similar to that described above. In this approach, the conduction joints can be cured at a temperature of, for example, approximately 140 ° C to 170 ° C, and under a pressure of, for example, approximately 0.1 atmospheres at 1.0 atmospheres, or approximately Q.> 3 atmospheres at 1.0 atmospheres, or about 0.5 atmospheres at 1.0 atmospheres.

Generally, the higher the temperature at which the epoxy is cured, the more conductive the bond is.

In some variations, the substrate and,zor one or more delamination layers placed below a series connected chain of superimposed solar cells are configured to have a surface that conforms in shape to the lower side of the chain in a tejamanil manner of solar cells. For example, a metal substrate may be in pattern to have a surface with a cross-section in saw teeth that conforms to the shape of the lower side of the chain in a solar cell tejamanil manner. In addition to or alternatively, one or more dielectric sheets placed between the substrate and the solar cells can be accommodated or have a pattern to provide such a surface that fits. For example, such dielectric sheets may be superimposed on a tejamanil pattern that provides an upper surface that conforms to the lower side of the solar cells in a tejamanil manner. Supporting the chain in a solar cell tejamanil manner with an adjustable supporting surface can improve thermal contact between the solar cells and the substrate.

Solar energy collectors comprising the series connected chains of superimposed solar cells as described herein may preferably be oriented with the exposed edges of the solar cells (e.g., edges 12 in Figure 3A) away from the equator. .

With solar cells in a tejamanil manner oriented in this manner, the solar radiation incident on the cells will illuminate only the upper surfaces of the cells, not the exposed edges. This can increase efficiency * *

two with which the collector converts the incident solar radiation into electrical energy, because the incident solar radiation on the exposed edges of the solar cells may not be efficiently converted into electricity.

The performance characteristics of solar cells

<td>they can</td><td>vary between</td><td>cells</td><td>solar even</td><td colspan="2">when</td><td>the cells</td>

<td>they have</td><td>essentially</td><td>designs</td><td>identical</td><td>By</td><td>the</td><td>both two</td>

<td>cells</td><td>solar of</td><td>design</td><td>identical</td><td>what</td><td>I know</td><td>light up</td>

<td colspan="2">identically they can</td><td>production</td><td>r streams</td><td>from</td><td>two</td><td>magnitudes</td>

different. In a string of solar cells connected in series, however, all cells must handle an identical current. The mismatches between the performances of the cells in the chain decrease the overall efficiency of the chain. This problem can be easily treated with chains connected in series of superimposed solar cells as described in this document. In any of the variations described above, the area of each solar cell not superimposed by adjacent solar cells can be selected to be adjusted or substantially adjusted with the electrical performance (e.g., current) of all other solar cells. In the chain. That is, the overlap between adjacent cells can be adjusted to vary the illuminated area of each solar cell such that the electrical performance of each solar cell is substantially adjusted with

3 that of the other solar cells. This can improve the overall efficiency of the chain.

This disclosure is illustrative and not limiting.

Additional modifications will be apparent to those skilled in the art in light of this disclosure and are intended to fall within the scope of the appended claims.

NOVELTY OF THE INVENTION

Having described the present invention as above, it is considered as a novelty and, therefore, the content in the following is claimed as property:

Contents7

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Document	Office	Kind	Date
13672386	United States of America	–	2012-11-08
201213672386	United States of America	A	2012-11-08
201213672386	United States of America	A	2012-11-08
201261734239	United States of America	P	2012-12-06
201261734239	United States of America	P	2012-12-06
61734239	United States of America	–	2012-12-06
13801432	United States of America	–	2013-03-13
201313801432	United States of America	A	2013-03-13
201313801432	United States of America	A	2013-03-13
2013069161	United States of America	W	2013-11-08
2013069161	United States of America	W	2013-11-08
13672386	–	–	–
13801432	–	–	–
61734239	–	–	–
PCTUS2013069161	–	–	–
US201213672386	–	–	–
US201261734239P	–	–	–
US201313801432	–	–	–
WO2013US69161	–	–	–

Members208

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US2014124013A1	United States of America	A1	2014-05-08
US2014124014A1	United States of America	A1	2014-05-08
WO2014074826A2	World Intellectual Property Organization (WIPO)	A2	2014-05-15
WO2014074826A3	World Intellectual Property Organization (WIPO)	A3	2014-07-24
KR20150084891A	Republic of Korea	A	2015-07-22
CN104919597A	China	A	2015-09-16
EP2917940A2	European Patent Office (EPO)	A2	2015-09-16
CL2015000999E1	Chile	E1	2015-11-06
CL2015000999S1	Chile	S1	2015-11-06
JP2015534288A	Japan	A	2015-11-26
US2015349145A1	United States of America	A1	2015-12-03
US2015349153A1	United States of America	A1	2015-12-03
US2015349161A1	United States of America	A1	2015-12-03
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US2015349167A1	United States of America	A1	2015-12-03
US2015349168A1	United States of America	A1	2015-12-03
US2015349169A1	United States of America	A1	2015-12-03
US2015349170A1	United States of America	A1	2015-12-03
US2015349171A1	United States of America	A1	2015-12-03
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US2015349173A1	United States of America	A1	2015-12-03
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US2015349175A1	United States of America	A1	2015-12-03
US2015349176A1	United States of America	A1	2015-12-03
US2015349190A1	United States of America	A1	2015-12-03
US2015349193A1	United States of America	A1	2015-12-03
US2015349701A1	United States of America	A1	2015-12-03
US2015349702A1	United States of America	A1	2015-12-03
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WO2015183827A2	World Intellectual Property Organization (WIPO)	A2	2015-12-03
CL2015001239A1	Chile	A1	2015-12-18
MX2015005844A	Mexico	A	2016-01-12
WO2015183827A3	World Intellectual Property Organization (WIPO)	A3	2016-01-21
US9241573B1	United States of America	B1	2016-01-26
USD750556S	United States of America	S	2016-03-01
TW201611317A	Taiwan Province of China	A	2016-03-16
US9356184B2	United States of America	B2	2016-05-31
EP2917940A4	European Patent Office (EPO)	A4	2016-07-06
US9397252B2	United States of America	B2	2016-07-19
US9401451B2	United States of America	B2	2016-07-26
USD767484S	United States of America	S	2016-09-27
US9473506B1	United States of America	B1	2016-10-18
US9484484B2	United States of America	B2	2016-11-01
AU2015267239A1	Australia	A1	2016-11-24
US9531678B1	United States of America	B1	2016-12-27
CN106489211A	China	A	2017-03-08
US2017077343A1	United States of America	A1	2017-03-16
US2017085217A1	United States of America	A1	2017-03-23
EP3149775A2	European Patent Office (EPO)	A2	2017-04-05
MX347994B	Mexico	B	2017-05-22
KR20170057177A	Republic of Korea	A	2017-05-24
EP3149775A4	European Patent Office (EPO)	A4	2017-06-07
CL2016003045A1	Chile	A1	2017-06-09
JP2017517145A	Japan	A	2017-06-22
CN106489211A8	China	A8	2017-06-30
BR112015010575A2	Brazil	A2	2017-07-11
MX2016015573A	Mexico	A	2017-07-13
US9780253B2	United States of America	B2	2017-10-03
US9876132B2	United States of America	B2	2018-01-23
US9882077B2	United States of America	B2	2018-01-30
US9947820B2	United States of America	B2	2018-04-17
CN108091703A	China	A	2018-05-29
CN108091705A	China	A	2018-05-29
US10025599B1	United States of America	B1	2018-07-17
CN108305904A	China	A	2018-07-20
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US10038673B1	United States of America	B1	2018-07-31
US10090430B2	United States of America	B2	2018-10-02
US2018323333A1	United States of America	A1	2018-11-08
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KR20180137608A	Republic of Korea	A	2018-12-27
KR20190000366A	Republic of Korea	A	2019-01-02
KR20190000367A	Republic of Korea	A	2019-01-02
JP2019004155A	Japan	A	2019-01-10
CN109216490A	China	A	2019-01-15
AU2018279029A1	Australia	A1	2019-01-17
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AU2018279035A1	Australia	A1	2019-01-17
US2019051789A1	United States of America	A1	2019-02-14
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US2019081198A1	United States of America	A1	2019-03-14
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CN109768095A	China	A	2019-05-17
CN109768095A	China	A	2019-05-17
TWI660518B	Taiwan Province of China	B	2019-05-21
EP3489848A1	European Patent Office (EPO)	A1	2019-05-29
MX365318BThis record	Mexico	B	2019-05-29
JP2019096886A	Japan	A	2019-06-20
CN108091705B	China	B	2019-07-02
EP3506134A2	European Patent Office (EPO)	A2	2019-07-03
AU2015267239B2	Australia	B2	2019-07-04
AU2018279029B2	Australia	B2	2019-07-11
AU2018279033B2	Australia	B2	2019-07-11
AU2018279035B2	Australia	B2	2019-07-11
CN110010706A	China	A	2019-07-12
EP3506134A3	European Patent Office (EPO)	A3	2019-07-31

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High efficiency configuration for solar cell string.

Abstract

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