Button cells and method for producing same

0001The present invention includes two metal housing semifields that are separated from each other by an electrically insulating seal and that form a housing with a flat bottom region and a flat lid region parallel to it, and inside the housing. A button cell battery having an electrode-separator complex having at least one positive electrode and at least one negative electrode, formed as a flat layer and coupled to each other via at least one flat separator, and the like. Regarding how to manufacture button batteries.

0002A button cell cell usually has a housing consisting of a battery cup and a battery lid, which are two housing semifield parts. These can be manufactured as press drawing parts from, for example, nickel-plated metal thin plates for deep drawing. Usually, the battery cup is given positive polarity and the housing lid is given negative polarity. Inside the housing can include various electrochemical systems such as zinc / manganese dioxide, primary and secondary lithium systems, or secondary systems such as nickel / cadmium or nickel / metal hydroxides.

0003For example, rechargeable coin cell batteries based on nickel metal hydroxide or lithium ion systems are extremely widespread. In the case of lithium-ion coin cell batteries, the electrochemically active material inside the coin cell housing is not usually arranged in the form of individual tablet-shaped electrodes separated from each other by a separator. Instead, the preformed electrode-separator composite is preferably inserted flat into the housing. In that case, a porous plastic film is preferably used as the separator, and the electrodes are laminated or adhered in a plane on the porous plastic film. In that case, the entire complex consisting of the separator and the electrode usually has a maximum thickness of several hundred μm. Therefore, multiple complexes of this type are often inserted flat on top of each other to allow them to fill a button cell housing of normal dimensions. In this way, in principle, a stack of arbitrary height can be obtained according to the dimensions of the button battery housing provided for incorporating the stack. That is, it is guaranteed that the provided housing internal space is optimally utilized.

0004Of course, in a button battery having this kind of stacking body composed of an electrode / separator complex, various problems due to the structure also occur. For one thing, of course, it is necessary that electrodes of the same polarity are connected inside the stack and then contact the corresponding poles of the coin cell housing. The required electrical contacts bring material costs, and the space occupied by the contacts is no longer utilized for active materials. Moreover, the production of electrode stacks is complex and expensive. This is because defects are likely to occur when the complexes are brought into contact with each other, which increases the scrap generation rate. On the other hand, it has been confirmed that button batteries having a stack consisting of electrodes and separators lose their sealing property very rapidly.

0005Liquid-tight closure of button batteries is traditionally done by placing the edge of the battery cup on the edge of the battery lid and bending the edge in combination with a plastic ring, which is the battery. It is placed between the cup and the battery lid and is used at the same time as a sealing member and to electrically insulate the battery cup and the battery lid. This type of button cell battery is described, for example, in German Patent Publication No. DE3113309.

0006However, instead, it is also possible to manufacture a button cell battery having no edge-bent cup edge, in which the battery cup and the battery lid are integrally held in the axial direction only by coupling by force fitting. A button cell battery of this type and a method of manufacturing it is described in a German patent application with document symbol 102009017514.8, which has not yet been published. However, despite the various advantages that this type of coin cell battery without edge bending can have, it has an axial load than a comparable coin cell battery with edge bent cup edges. Cannot be applied, especially with respect to the axial mechanical load generated inside the coin cell battery. That is, for example, the electrodes of a rechargeable lithium-ion system are constantly exposed to volume changes during the charging and discharging process. The axial force generated at that time brings about non-airtightness more easily in the button battery having no edge bending portion than in the case of the button battery having the edge bending portion, of course.

<p num="0007"> An object of the present invention is to provide a button battery in which the above-mentioned problems occur only to the extent that they are completely or significantly reduced. This coin cell battery is more conventional than conventional coin cell batteries, especially against mechanical loads generated in the axial direction, even when it is formed as a coin cell battery that does not have a cup edge with a bent edge. Must be more resistant than coin cell batteries.</p>

<p num="0008"> This problem is solved by a button battery having the feature of claim 1. Preferred embodiments of button batteries according to the present invention are defined in Dependent Claims 2-10. The method according to claim 11 also contributes to solving the problem according to the present invention. Preferred embodiments of the method according to the invention are defined in Dependent Claims 12-14. With this, the wording of the entire claim is made into the content of this specification by reference.</p><p num="0009"> The coin cell batteries according to the present invention always have two metal housing semifields, which are separated from each other by an electrically insulating seal and have a flat bottom region and a flat lid parallel to it. Form a housing with a region. The two housing semifields are usually the so-called housing cup and housing lid, as already mentioned at the beginning. As the housing semi-body portion, a portion made of a nickel-plated steel plate or a thin metal plate is particularly preferable. Further, as the metal material, in particular trimetals having an order of, for example, nickel and steel (or special steel) and copper is suitable (in which case the nickel layer forms a preferably outer layer of the coin cell housing. A copper layer preferably forms an inner layer).</p><p num="0010"> As the seal, for example, an injection molded seal or a film seal can be used. The latter is described, for example, in DE19647593.</p><p num="0011"> The button battery according to the present invention includes an electrode / separator complex having at least one positive electrode and at least one negative electrode inside the housing. The electrodes exist in the form of a flat electrode layer. The electrodes are coupled to each other via a flat separator. Preferably, the electrodes are laminated or glued onto the separator. Electrodes and separators usually have a thickness in the μm range only. As the separator, a porous plastic film is usually used.</p><p num="0012"> Unlike the button cell batteries mentioned at the beginning, the button cell batteries according to the present invention in particular have a very special orientation of the electrode layer, that is, substantially perpendicular to the flat bottom region and the lid region. It is characterized by being oriented. A button cell battery with a stacked electrode-separator composite, known from the prior art, always has it inserted flat so that the electrode layer is substantially relative to the flat bottom and lid regions. However, in the button battery according to the present invention, the situation is different.</p><p num="0013"> The vertical orientation of the electrode layer has an unexpectedly significant advantage, that is, this orientation significantly improves the sealing properties of the coin cell batteries according to the present invention, especially in coin cell batteries based on lithium ion systems. Was revealed to be accompanied by. The electrodes of a rechargeable lithium-ion system are constantly exposed to volume changes during the charging and discharging processes. Of course, the electrode of the button battery according to the present invention may also bring about this kind of volume change. However, the mechanical force generated in that case no longer acts mainly in the axial direction, as in the case of stacking of flatly inserted electrode-separator complexes. The force acts rather radially based on the vertical orientation of the electrodes. Radial forces can be absorbed much more by the coin cell housing than axial forces. The improved sealing properties are believed to be due to this.</p><p num="0014"> Particularly preferably, the electrode of the button battery and the flat separator according to the present invention are formed in a band shape or a band shape, respectively. That is, in order to manufacture the button battery according to the present invention, for example, a separator material existing as an endless ribbon can be used as a base, on which electrodes are provided in a planar shape, particularly in the form of a band or a rectangle. And especially laminated.</p><p num="0015"> Within the housing of the coin cell battery according to the present invention, the complex is particularly preferably present in the form of a roll, particularly in the form of a spiral roll. Rolls of this type are very easily formed according to known methods (see, eg, DE3638793), in which the electrodes are provided in a planar, particularly strip-like manner, especially on a separator that exists as an endless band, and are particularly laminated. In that case, the complex consisting of the electrode and the separator is usually wound on a so-called winding core. After removing the roll from the winding core, an axial hollow chamber remains in the center of the winding core. As a result, the roll may relax into this hollow chamber in some cases. However, this can, in some cases, cause problems when the electrodes make electrical contact with the metal housing semifield, which will be described in more detail below.</p><p num="0016"> The electrode rolls are arranged inside the coin cell battery according to the present invention, preferably so that the end faces of the rolls face toward a flat bottom region and a flat lid region (thus the electrode layer of the roll is of the housing. Oriented perpendicular to the flat bottom and lid areas).</p><p num="0017"> According to the present invention, in a preferred embodiment, a coin cell battery according to the present invention has a solid roll core at the center of the roll, which at least partially fills an axial hollow chamber at the center of the roll. ing. This type of roll core fixes the electrode roll in the radial direction and prevents the roll from collapsing internally into the axial hollow chamber in some cases. When the roll is loosened in this way, the pressure exerted by the end face of the roll in the axial direction and, in some cases, in the direction of the output conductor (which will be described later) arranged therein, is also weakened. When this is prevented, there is usually no problem with electrical contact between the electrodes and the metal housing semifield.</p><p num="0018"> Further, this type of roll core also improves the stability of the button battery according to the present invention against external mechanical influences. It is usually no longer possible for the electrode rolls in the coin cell to be damaged by external axial mechanical pressure.</p><p num="0019"> According to a preferred embodiment of the electrode roll as a spiral electrode roll, the above-mentioned axial hollow chamber at the center of the roll is preferably formed in a substantially cylindrical shape (preferably particularly cylindrical shape). The outside of the hollow chamber is defined by rolls, and the end side of the hollow chamber is defined by the corresponding surfaces of the bottom or lid region of the coin cell housing.</p><p num="0020"> Similarly, the roll core contained in the button battery according to the present invention is also preferably formed as a cylinder, particularly as a hollow cylinder. The height of this type of cylinder preferably corresponds to the distance between the flat bottom region and the parallel and flat lid region relative to it.</p><p num="0021"> In a particularly preferred embodiment, the roll core may have the property of self-expanding in the radial direction. For example, the roll core has a structure compressed in the radial direction and can be introduced into a hollow chamber in the axial direction of the roll of the button battery according to the present invention. As the radialally compressed roll core relaxes, the roll core exerts radial pressure on the surrounding electrode rolls, thus also ensuring axial contact pressure.</p><p num="0022"> As the roll core that self-expands in the radial direction, for example, a hollow cylinder having a slit in the axial direction can be used. But instead, other materials that self-expand, for example, in the radial direction of the plastic base are conceivable.</p><p num="0023"> Particularly preferably, the roll core is made of a metal or plastic such as special steel.</p><p num="0024"> Particularly preferably, the complex consisting of electrodes and separators in a coin cell battery according to the present invention has one of the following layer sequences: Negative electrode / separator / positive electrode / separator; or Positive electrode / separator / negative electrode / separator.</p><p num="0025"> This type of complex is extremely easy to make and is wound up without causing a short circuit between electrodes of opposite polarity.</p><p num="0026"> The separator that can be used in the button cell battery according to the present invention is preferably a film made of at least one plastic, particularly at least one polyolefin. At least one polyolefin is, for example, polyethylene. However, it is also possible to use a multi-layer separator, eg, a separator consisting of a series of various polyolefin layers, eg, having a polyethylene / polypropylene / polyethylene order.</p><p num="0027"> It is not always necessary to use multiple separate separators to form the complex of the order described above. Rather, one separator can also be folded back around the end of one of the electrodes, resulting in both sides of the electrode being covered by the one separator.</p><p num="0028"> The separator that can be effectively used in the button cell battery according to the present invention preferably has a thickness between 3 μm and 100 μm, particularly between 10 μm and 50 μm.</p><p num="0029"> The electrode of the button battery according to the present invention preferably has a thickness between 10 μm and 1000 μm, particularly between 30 μm and 500 μm.</p><p num="0030"> In a preferred embodiment of the button cell battery according to the present invention, the negative electrode and the positive electrode in the electrode / separator complex are arranged so as to be offset from each other inside the complex. The staggered arrangement means that the electrodes are arranged as follows, that is, so that the electrodes are spaced apart from each other with respect to the flat bottom region and the lid region in the button battery according to the present invention. In the simplest case, for example, the positive and negative electrodes, such as strips of the same width, are mounted slightly offset on both sides of the separator ribbon so that the distance between the positive electrodes with respect to the upper separator edge is negative. Greater than similar intervals measured from the electrodes. Of course, the opposite is true for the spacing with respect to the lower separator edge.</p><p num="0031"> In a particularly preferred embodiment, preferably as a result of this misalignment, the positive electrode, especially the edge of the positive electrode, comes into direct contact with the cup portion, especially within the flat bottom region of the cup portion, and is negative. The edges of the electrodes, especially the negative electrodes, come into direct contact with the lid portion, especially within the flat lid region of the lid portion. In this embodiment, there is direct electrical and mechanical contact between the electrode and the cup or lid portion. Therefore, staggering the electrodes with respect to each other allows contact between the electrodes and their respective housing portions, eliminating the need for additional electrical contact and connecting means.</p><p num="0032"> In an alternative preferred embodiment, of course, at least one of the electrodes, preferably at least one negative electrode and at least one positive electrode in the coin cell battery according to the invention, is via one or more output conductors. It may be preferable to be connected to a flat bottom region and a lid region. The output conductor can be an output conductor lug made of, for example, copper or other suitable metal. On the electrode side, the output conductor can be connected, for example, to a current collector. The connection of the output conductor to the housing and / or current collector can be made, for example, by welding or by clamp coupling.</p><p num="0033"> In the simplest case, the current collectors of the positive and negative electrodes themselves can also function as output conductors. This type of collector is usually a metal foil or mesh embedded within each electrode material. The uncovered partial area of this type of collector, especially the termination piece, can be bent into contact with the coin cell housing.</p><p num="0034"> The use of output conductors is particularly such that the negative and positive electrodes are spaced relative to each other, especially within the complex, that is, for the electrodes, equal spacing for the flat bottom and lid regions, respectively. It may be preferable if it is arranged. Alternatively, in another expression, it may be preferable when the electrodes are not arranged so as to be displaced from each other as described above inside the electrode-separator complex.</p><p num="0035"> Of course, if the electrodes of opposite polarity are equally separated from the flat bottom region and the lid region, there is a risk of a short circuit as the positive and negative electrodes will come into contact with the metal cup or lid at the same time. To do. Thus, in a preferred embodiment, the coin cell battery according to the invention may have at least one insulating means, the insulating means being direct mechanical and electrical between the end face of the roll and the flat bottom and lid regions. Prevent target contact.</p><p num="0036"> In one development, it is preferred that the electrodes in the button cell of the present invention of this type are connected to the flat bottom and lid regions via the separate output conductors already described. This ensures electrical contact between the electrodes and the housing.</p><p num="0037"> In that case, it is preferable that at least a part of one or more output conductors is in flat contact with the inside of the housing semi-body portion within the bottom region or lid region of the housing. Of course, electrical contact between the output conductor and the inside of the housing is ideal if the output conductor is at least lightly pressed against the housing (if it is not welded from the beginning). This can be achieved surprisingly effectively by properly arranging the roll cores described above within the coin cell battery according to the present invention.</p><p num="0038"> The insulating material can be, for example, a flat layer made of plastic, such as a plastic film, arranged between the end face of the roll and the flat bottom and lid areas of the button cell housing according to the invention.</p><p num="0039"> The button battery according to the present invention corresponding to the above description is particularly a rechargeable button battery. Particularly preferably, the button cell battery according to the present invention has at least one lithium insertion electrode.</p><p num="0040"> In coin cell batteries, the ratio of height to diameter is essentially less than one. Preferably, this ratio is between 0.1 and 0.9, especially between 0.15 and 0.7, in the coin cell batteries according to the invention. In that case, the height is the distance between the flat bottom region and the flat lid region parallel to it. The diameter is the maximum distance between the two points on the outer surface area of the coin cell battery.</p><p num="0041"> Particularly preferably, the button battery according to the present invention is a button battery that does not have an edge bending portion as described in the patent application having the document symbol 102009017514.8, which has already been described at the beginning. Therefore, there is preferably only a force-fitting bond between the housing semi-body parts. Therefore, the button battery according to the present invention does not have a cup edge that has been edge-bent, as is always the case with conventional button batteries. The coin cell battery is closed without a bent edge.</p><p num="0042"> Usually, for this kind of button cell without edge bending, conventional battery cups and battery lids are utilized, which are the bottom area or lid area and the outer surface area, and the bottom area or lid area, respectively. It has an edge region arranged between the outer side region and a cut edge. The battery cup and battery lid together form a housing, which forms a housing for the usual internal components of a coin cell battery, such as electrodes, separators, and the like. As usual, within this housing, the bottom area of the battery cup and the lid area of the battery lid are oriented substantially parallel to each other. The outer surface regions of the battery cup and battery lid in the finished button cell are oriented substantially perpendicular to the bottom or lid region, preferably having a substantially cylindrical geometry. doing. Preferably, the inner and outer diameters of the battery cup and battery lid are substantially constant within the outer surface region. The above-mentioned edge region of the battery cup and the battery lid forms a transition portion between the outer surface region and the lid region, or between the outer surface region and the bottom region. Thus, they are defined on the one hand by a substantially flat formed bottom region and lid region, and on the other hand by a substantially cylindrical outer surface region arranged perpendicular to them. Will be done. The edge region can also be formed, for example, as a sharp edge or chamfered.</p><p num="0043"> In order to manufacture a coin cell battery without edge bending, at least one seal is usually mounted on the outer surface region of the battery lid. Then, in another step, the lid having the attached seal is inserted into the battery cup, so that a region where the battery cup and the outer surface region of the battery lid overlap is generated. In that case, the size of the overlapping region or the ratio of the overlapping region to the non-overlapping region is determined by the height of each of the outer surface region of the battery cup and the outer surface region of the battery lid, and by the depth of insertion. With respect to the outer surface area of the battery lid, it is effective that between 20% and 99%, especially between 30% and 99%, particularly preferably between 50% and 99%, overlaps with the outer surface area of the battery cup. (Percentages are relative to the height of the outer or outer surface area, respectively). Other conventional components of coin cell batteries (electrodes, separators, electrolytes, etc.) can be inserted into the housing cup and / or into the housing lid prior to insertion. After the battery lid is completely inserted into the battery cup, pressure is applied on the outer surface area of the battery cup, especially within the area of the cut edge, to seal the housing. In this case, the housing portions joined together should be as unloaded as possible in the axial direction, or should be loaded with very little load. Therefore, the pressure is applied especially in the radial direction. That is, apart from the housing seal described above, the outer diameter of the battery housing can also be corrected.</p><p num="0044"> Of particular importance is that the height of the outer surface area of the battery cup and battery lid is as follows, i.e., due to the pressure exerted by the cut edge of the battery cup on the outer surface area of the battery cup, the outer surface area of the battery lid. They are adjusted to each other so that they are pressed against each other. Therefore, the height of the outer surface region is preferably selected so that the cut edge of the battery cup cannot be bent inward beyond the edge region of the battery lid fully inserted into the battery cup. Has been done. Therefore, the cut edge of the battery cup is not edge-bent on the edge region of the battery lid. As a result, the battery cup of a button cell battery formed according to the method according to the present invention has an outer surface region having a substantially constant radius in the direction of the cut edge.</p><p num="0045"> In a coin cell cell formed according to this type of method, there is preferably a bond only by force fitting between the battery cup, which is a housing component, the battery lid and the seal.</p><p num="0046"> Therefore, holding the components together is preferably guaranteed by substantially only the anchoring force.</p><p num="0047"> Particularly preferably, a battery cup formed conically within at least a partial region of its outer surface such that at least its inner diameter increases in the direction of the cut edge is used to produce a coin cell cell without edge bending. used. This makes it significantly easier to insert the battery lid into the battery cup. The dimensions of the battery cup and battery lid are preferably adjusted relative to each other so that a relatively large reaction force is generated only when the lid is almost completely inserted into the cup. In that case, the cone angle is preferably between 10 minutes and 3 °, especially between 30 minutes and 1 ° 30 minutes.</p><p num="0048"> The battery lid, which is inserted into the battery cup with the attached seal, is formed in a cylindrical shape in at least a part of the outer surface region in a preferred embodiment. This particularly relates to a portion of the outer surface region that overlaps the partial region of the outer surface of the battery cup, which is formed in the above-mentioned conical shape after the battery lid is inserted into the battery cup. Particularly preferably, the outer surface of the battery lid and thus the outer surface region are also formed in a cylindrical shape as a whole. Therefore, preferably, the battery lid has a constant outer diameter within the outer surface region. This particularly relates to a portion that overlaps the conical portion of the outer surface region of the battery cup after the battery lid has been inserted, in some cases.</p><p num="0049"> When inserting a battery lid having a cylindrical outer surface region into a conical battery cup in at least a partial region of the outer surface, as described above, usually between the battery cup and the battery lid. , An upwardly open gap is created. This gap is usually removed again by the pressure applied to the outer surface area of the battery cup. That is, the pressure applied to the outer surface region of the battery cup is as follows, that is, the conical portion of the outer surface region of the battery cup is applied to each other within the region where the inside of the battery cup and the outside of the battery lid overlap each other. It is selected to be pressed inward until it is substantially evenly spaced. The resulting button cell has outer surface regions oriented parallel to each other, especially in overlapping regions.</p><p num="0050"> An important point of view in that case is the selection of the seal that binds the battery cup to the battery lid. Preferably, the seal is a plastic seal made of a thermoplastic material.</p><p num="0051"> Particularly preferably, the plastic seal is a film seal, for example as described in DE19647593 already mentioned, and particularly a film seal made of a thermoplastic substance.</p><p num="0052"> The film seal can be formed with a very uniform thickness. When appropriate pressure is applied onto the outer surface region of the battery cup, a tight fit occurs, and the tight fit results in the coin cell cell formed with extremely good sealing properties. That is, the use of film seals in particular makes it possible to omit the edge bending process of the edge of the battery cup, and as a countermeasure it is not necessary to accept the drawbacks in other important properties.</p><p num="0053"> Here, it is particularly preferred that a polyamide-based or polyetheretherketone-based plastic seal, especially a plastic film, be used.</p><p num="0054"> Preferably, the edge-bentless battery seal has an initial thickness between 50 μm and 250 μm, particularly preferably between 70 μm and 150 μm, especially about 100 μm. In that case, the concept of "initial thickness" is the thickness that the seal has before it is mounted on the outer surface of the battery lid. On the contrary, the concept of "final thickness" is the thickness of the seal inside the finished battery. It is clear that this usually corresponds to the distance between the inside of the battery cup and the outside of the battery lid, at least within the overlapping areas.</p><p num="0055"> Both the outer and inner diameters of the cup and lid should be adapted to each other and to the thickness of the film seal to allow for sufficiently high friction between the battery cup and the battery lid. Is. Only in such cases is it possible to generate a sufficiently high press pressure to bring the two separate parts together. The portion used in that case is preferably the smallest in the outer diameter of the cut edge of the battery lid inserted into the battery cup and in the outer surface region of the battery cup that overlaps the outer surface region of the battery lid. The difference from the inner diameter needs to be less than the initial thickness of the seal used. Particularly preferably, this difference is between 10% and 90% of the initial thickness, especially between 30% and 70%, particularly preferably about 50%.</p><p num="0056"> After inserting the battery lid into the battery cup, a portion of the outer surface region of the battery cup can be narrowed inward in the radial direction. In that case, in particular, that portion is a portion of the outer surface region that does not overlap with the outer surface region of the battery lid.</p><p num="0057"> It was clarified that this radial narrowing provided a significant improvement in sealing properties. By narrowing the outer surface of the cup, radial pressure is applied to the edge of the housing cup that contacts the inner wall, or to the seal located between the housing lid and the housing cup, resulting in the seal being within this area. Compressed with.</p><p num="0058"> The narrowing down can be performed at the same time as applying pressure on the outer surface region of the battery cup described above, but preferably the narrowing down is performed in another step later.</p><p num="0059"> The method for manufacturing a button cell battery according to the present invention is particularly for manufacturing a button cell battery as described above, that is, a button cell battery having a housing having a flat bottom region and a flat lid region parallel to the flat bottom region. Can be used. This method is suitable for producing a button battery having no edge bending portion and for producing a button battery having an edge bending portion.</p><p num="0060"> Therefore, with respect to preferred embodiments of the individual components (housing portion and housing dimensions, electrodes, separators, etc.) used in the method according to the invention, the above-described embodiments and descriptions can be referred to in its entirety. Can be instructed to do so.</p><p num="0061"> The housing is usually assembled from a metal cup portion (housing cup) and a metal lid portion (housing lid), in which case an electrode-separator complex with electrodes formed as a flat layer follows into the housing. Is inserted so that the electrodes are oriented perpendicular to the flat bottom and lid regions.</p><p num="0062"> As already mentioned, the electrode-separator complex is preferably incorporated in the form of a roll, especially as a spiral roll.</p><p num="0063"> Generally, the method according to the present invention has the following steps: The stage of inserting the roll into the metal lid, and There is always a step of inserting the metal lid portion with the roll into the metal cup portion.</p><p num="0064"> Then, optionally, the edge of the cup portion is bent on the edge of the lid portion.</p><p num="0065"> As long as a button cell without edge bending is formed, the same steps described above will be performed.</p><p num="0066"> Prior to closing the housing, the electrodes are usually further impregnated with an electrolyte solution.</p><p num="0067"> The roll is preferably wrapped around the core upon insertion. In that case, the winding core can be removed after or at the time of insertion. In some cases, the roll core described above is then inserted. Alternatively, the electrode-separator complex can also be wound directly onto this type of core.</p><p num="0068"> Particularly preferably, the spiral roll is heat treated on its end face prior to assembly. In that case, the roll is exposed to a temperature at which the separator in the roll is thermoplasticly deformable, at least for a short period of time. The separators usually project slightly at the end faces of the rolls, even assuming that the electrodes are staggered relative to each other as described above. The heat treatment causes the separator to shrink somewhat, which in some cases allows the edges of adjacent electrodes to be exposed, so that the edges can come into direct contact with the coin cell housing.</p><p num="0069"> The above-mentioned advantages and other advantages of the present invention are revealed in the following drawings in combination with the sub-claims. In that case, the individual features of the present invention can be realized either alone or in combination with each other. The embodiments described above are used solely to explain and better understand the invention and are by no means limiting.</p>

0070<figref num="1">It is a schematic cross-sectional view of the preferable embodiment of the button battery which concerns on this invention.</figref><figref num="2">It is a figure which shows the effect of the heat treatment of the wound electrode-separator complex used in the preferable embodiment of the method which concerns on this invention.</figref><figref num="3">It is a figure which shows the electrode-separator complex in the form of a roll which can be incorporated in the button battery which concerns on this invention.</figref><figref num="4">It is sectional drawing which shows the other preferable embodiment of the button battery which concerns on this invention.</figref><figref num="5">FIG. 5 is a cross-sectional view schematically showing a preferred embodiment of a button battery according to the present invention, in which the edge of the battery cup is not edge-bent on the edge of the battery lid.</figref>

0071FIG. 1 schematically shows a cross section of a preferred embodiment of the button battery 100 according to the present invention. It has a metal cup portion 101 and a metal lid portion 102. Both parts are hermetically coupled to each other by a seal 109. Together they form a housing with a flat bottom region 103 and a flat lid region 104 parallel to it. In use, these flat areas 103 and 104 form a pole of the button cell battery, from which current can be drawn by a load. The edge 110 of the battery cup 101 is edge-bent inward beyond the edge of the battery lid 102.

0072Inside the electrode, a composite composed of a band-shaped electrode 105, a band-shaped electrode 106, and a band-shaped separator 107 is arranged. In that case, the complex consisting of the electrodes 105 and 106 and the separator 107 exists in the form of a roll, and the end face of the roll is in contact with the flat bottom region 103 and the parallel and flat lid region 104. .. The complex is wound onto the core 108 at the center of the coin cell battery 100. Both the core 108 and the electrodes and separators wrapped around it are oriented perpendicular to the flat bottom region 104 and lid region 103. As long as the volume of the electrodes increases or decreases during the charging or discharging process, the mechanical force exerted at that time acts primarily in the radial direction and can be absorbed by the outer surface region of the coin cell cell 100.

0073It should be emphasized that the positive electrode 105 and the negative electrode 106 are in direct contact with the cup portion 101 or the lid portion 102 of the button cell battery 100, respectively. No separate output conductor is required to connect the electrodes to the lid portion 102 and the cup portion 101.

0074FIG. 2 shows the effect of the heat treatment of the electrode / separator roll 200 provided in the preferred embodiment of the method for manufacturing a button battery according to the present invention. A roll 200 consisting of a composite of a positive electrode 201 (horizontal striped bar), a negative electrode 202 (white bar) and a separator 203 (one cross section) is shown schematically. The positive electrode 201 and the negative electrode 202 are arranged so as to be offset from each other. Separator 203 is made of a thermoplastically deformable material.

0075When the separator edges located on the end faces 204 and 205 of the roll 200 are exposed to a high temperature (for example, 250 ° C as shown), the separator edges shrink. The separator retracts at least partially between adjacent electrodes. In that case, on the end face 204, the edge of the negative electrode 202 is exposed, while the edge of the positive electrode 201 is covered. At the end face 205, the edge of the positive electrode 201 is exposed and the edge of the negative electrode 202 is covered.

0076When using rolls treated in this way, electrodes of the same polarity are guaranteed to be in direct contact with the housing cup only or only with the housing lid, respectively. No separate electrical connection is required between the electrodes and the housing portion.

0077FIG. 3 shows an electrode-separator complex for a button battery according to the present invention in the form of a roll 300. In this case, in the display A, one of the end faces 301 of the roll 300 is a plan view from above vertically. It is shown, and in display B, the roll 300 is shown obliquely from above. In both cases, it is shown that the complex has two layers of separators 302 and 303 and two electrode layers 304 and 305 (positive and negative electrodes). The complex is spirally wound up and tied together by adhesive tape 306 on the outside.

0078FIG. 4 shows a preferred embodiment of the button battery 400 according to the present invention in cross-sectional view. It is shown that the coin cell battery housing consists of a cup portion 401 and a lid portion 402 with a seal 403 located between them. Inside the housing is a composite of electrodes and separators, as shown in FIG. 3, as a spiral roll 404 (schematically shown in cross section). Again, the separator 405 and separator 406 and the electrodes 407 and 408 having opposite polarities are well shown. In that case, the electrode 407 is connected to the lid portion 402 via the output conductor 410, while the electrode 408 is connected to the cup portion 402 via the output conductor 409. The output conductor 410 is preferably welded to the lid portion 402. The output conductor 409, on the other hand, is connected to the cup portion 402 by a clamp coupling (this output conductor is between the support ring 413 on which the edge of the battery lid rests and the bottom of the battery cup. It is pinched). Insulating means 411 and 412 are arranged between the end face of the roll and the cup portion 401 and the lid portion 402, and the insulating means are thin plastic disks, respectively. This prevents electrodes having opposite polarities from coming into contact with the cup portion 401 or lid portion 402 at the same time. This avoids short circuits.

0079FIG. 5 schematically shows a cross section of a preferred embodiment of the button battery 500 according to the present invention.

0080It has a metal cup portion 501 and a metal lid portion 502. Both said portions are hermetically coupled to each other by a seal 510. Together they form a housing with a flat bottom region 503 and a parallel, flat lid region 504 relative to it. In use, the flat areas 503 and 504 form a pole of the button cell battery, from which current can be taken out by a load.

0081Since the battery lid 502 is inserted into the battery cup 501, the battery lid and the outer surface area of the battery cup overlap, and in that case, the inner diameter of the battery cup 501 in the overlapping area is substantially in the direction of the cutting edge. Is constant. Therefore, the edge of the battery cup 501 is not edge-bent on the edge 511 of the battery lid 502, and therefore the preferred embodiment of the button cell 500 according to the invention described herein is the edge-bent portion. It is a button battery without an invention.

0082A composite composed of a band-shaped electrode 508, a band-shaped electrode 509, and a band-shaped separator 507 is arranged inside the electrode. In that case, the complex consisting of the electrodes 508 and 509 and the separator 507 exists in the form of a roll, the end faces of which are oriented in the direction of the flat bottom region 503 and the parallel and flat lid region 504. The composite is wound on the roll core 512 at the center of the button battery 500. Both the core 512 and the electrodes and separators wrapped around it are oriented perpendicular to the flat bottom region 503 and lid region 504. As long as the volume of the electrodes increases or decreases during the charging or discharging process, the mechanical force exerted in that case can act primarily in the radial direction and be absorbed by the outer surface region of the coin cell 500.

0083The positive and negative electrodes are in contact with the cup and lid, which are semifield parts of the housing, via the output conductor 505 and the output conductor 506. The output conductor 505 is made of aluminum and the output conductor 506 is made of nickel (or alternative copper). The two output conductors are thin foils that lie flat between the end face of the roll and the flat lid region 504 or cup region 503. The roll core 512 maintains a constant, light contact pressure on the output conductor. The output conductor is suitably separated from the end face of the roll by a separate insulating member (not shown in the drawing), for example a thin film.