Battery system and charge/discharge measuring apparatus

0001The present invention relates to a power amount management system during charging and discharging of a secondary battery and a battery system using the same.

0002In recent years, storage batteries (secondary batteries) such as lithium-ion batteries have become more and more popular in mobile communication devices such as laptop computers and mobile phones, hybrid cars and electric vehicles, and even residential storage batteries. Has also been used. Due to recent environmental problems, there is an increasing demand for reduction of energy consumption and power consumption, and it is expected that the use of storage batteries will be able to meet these demands. However, in order to utilize the storage battery for reducing the power consumption, the power consumption management (battery capacity management) of the storage battery is a big issue.

0003Conventionally, the electric energy management of a storage battery has been managed and controlled by estimating the charge / discharge amount using an empirical formula including time and temperature information based on the terminal voltage of the storage battery.

0004However, in the case of the conventional method, the storage status (change in battery capacity) of the storage battery is indirectly estimated by considering the time and temperature information based on the terminal voltage of the battery, so the estimation accuracy is limited. Yes, overcharging or insufficient charging may occur depending on the operating conditions and usage environment conditions. Further, in the conventional method, problems such as over-discharging occur at the time of discharging (when using a battery).

0005In addition, flammable materials are often used for storage batteries, and safety problems such as the risk of ignition due to overcharging are also pointed out. In addition, if the user is not aware of the insufficient charge of the storage battery, the charging time may be earlier than expected, which may cause inconvenience. On the other hand, over-discharging shortens the performance life of the battery due to the characteristics of the battery. In addition, when the remaining amount of the storage battery is displayed, the terminal voltage drops sharply when the remaining amount becomes low, and as a result, the sensuous "battery dead" time is earlier than expected, and the feeling of use is felt. There are also inconveniences such as not matching with.

0006The above problem is caused by the fact that the change in battery capacity during charging and discharging cannot be accurately detected depending on the operating status of the secondary battery and the operating environment conditions.

<p num="0007"><patcit num="1"><text>Japanese Patent Application Laid-Open No. 2009-232659</text></patcit><patcit num="2"><text>Japanese Unexamined Patent Publication No. 2001-332310</text></patcit></p>

<p num="0008"> The present invention has been created in view of the above problems, and provides a battery system and a charge / discharge measuring device capable of performing appropriate charge / discharge management by accurately measuring a capacity change of a secondary battery during charging / discharging. The purpose is to do.</p>

<p num="0009"> Specifically, the battery system according to the present invention is A rechargeable secondary battery and An inspection resistor connected between the terminals of the secondary battery via an inspection switch, A pair of external terminals extending from both electrodes of the secondary battery and provided in parallel with the inspection resistor, A voltmeter that measures the voltage between both electrodes of the secondary battery, Discharge power measuring means for measuring the amount of power discharged by the secondary battery, and A timer that measures the charge time and discharge time, Has a control unit When charging the secondary battery via the pair of external terminals, the control unit measures the charging time from the charging start voltage to the charging end voltage. After charging is completed, a current is passed through the inspection resistor by the inspection switch. It is characterized in that the amount of residual power is calculated based on the power consumed by the inspection resistor obtained by the discharge power measuring means and the charging time.</p><p num="0010"> Further, in the present invention, the current from the secondary battery is connected to the primary connection circuit for connecting the secondary battery, the load resistance and the conductor film in series, and the secondary battery, the charger and the conductor film are connected in series. Provided is a charge / discharge measuring device capable of switching between a second connection circuit to be connected to each other. This charge / discharge measuring device has a magnetic film that is arranged parallel to the conductor film and is connected in parallel to the connection from the secondary battery to the load resistance and the charger, and the magnetic film. It has a voltage detecting means for detecting a voltage change in the above.</p><p num="0011"> As will be described later, the present inventor has found that it is more useful to measure the capacity change of the secondary battery with a magnetic film power sensor than to measure the voltage between the terminals of the battery as in the conventional case. Based on this finding, the charge / discharge measuring device of the present invention has been provided. Specifically, the first connection circuit of the discharge system that passes a current parallel to the current from the secondary battery to the load through the magnetic film of the magnetic film power sensor, and parallel to the current from the storage battery to the secondary battery on the same magnetic film. It provides a circuit configuration in which a second connection circuit of a charging system that allows a large amount of current to flow and a circuit configuration that can be alternately switched for each charge / discharge.</p><p num="0012"> Further, in the charge / discharge measuring device of the present invention, two magnetic films are connected in series and a magnetic field due to a direct current is applied in opposite directions, and the voltage detecting means is an end portion of the two magnetic films in the current direction. The charge / discharge measuring device according to claim 1, wherein the output voltage between the two is differentially amplified to detect a voltage change.</p><p num="0013"> In the case of this charge / discharge measuring device, a magnetoresistive magnetic film power sensor is used. Since the magnetoresistive magnetic film power sensor measures the voltage change in the current direction, it is suitable for a narrow current path and is suitable for application to a smart grid or the like. On the other hand, as will be described later, a large bias voltage is generated in the output voltage of the magnetic film power sensor. In order to cancel (reduce) this, in this charge / discharge measuring device, two magnetic film elements are connected in series and a magnetic field due to an electric current is applied in the opposite direction. As a result, the opposite bias voltage is generated in each magnetic film, so that the bias voltage can be canceled by subtracting the output voltage.</p><p num="0014"> Further, the charge / discharge measuring device connects a dummy resistor in series with the magnetic film, and the voltage detecting means differentially amplifies the output voltage between the ends of the magnetic film and the dummy resistor in the current direction. A voltage change may be detected.</p><p num="0015"> This charge / discharge measuring device also utilizes a magnetoresistive effect type magnetic film power sensor, but here, the bias voltage is canceled by connecting a dummy resistor in series to the element of the magnetic film.</p><p num="0016"> Further, the magnetic film may be a plurality of short narrow magnetic films having a predetermined inclination angle θ1 with respect to the current direction arranged at intervals in the current direction.</p><p num="0017"> In the case of the magnetic film in the magnetoresistive magnetic film power sensor, the magnetic film of the element is formed in stripes at intervals in the direction of the load current. Further, each of the striped magnetic films is inclined with respect to the direction of the load current. For example, when the direction of the load current is from left to right, the magnetic film of the element is tilted to the right. A magnetic film having such a structure is referred to as a "barber pole magnetic film" in the present specification. In this case, it is not necessary to apply the magnetic field (bias magnetic field) by the direct current described above. This is because the magnetic field / resistance characteristic of the magnetic film of each element has a characteristic as if it is biased by a bias magnetic field.</p><p num="0018"> Further, in this charge / discharge measuring device, two magnetic films are connected in series, and one of the magnetic films is a short narrow magnetic film having a predetermined inclination angle θ1 with respect to the current direction in the current direction. A plurality of short narrow magnetic films having a predetermined inclination angle θ2 opposite to that of the one magnetic film with respect to the current direction are arranged with a space between them. The voltage detecting means can detect a change in the output voltage between the ends of the two magnetic films in the current direction.</p><p num="0019"> If reduced, the above-mentioned barber pole magnetic film is adopted, and when the magnetic films are connected in series so that the magnetic films have opposite inclinations with respect to the direction of the load current, for example, when the direction of the load current is from left to right, one of them. This is a case where the magnetic film of one element is tilted to the right and the magnetic film of the other element is tilted to the left. In the case of this configuration, each element (magnetic film) is arranged in a differential series, and only the change in the output voltage can be extracted with the magnetic field zero point as the operating point.</p><p num="0020"> Further, the voltage detecting means may detect a change in the output voltage between the ends in the width direction with respect to the current direction of the magnetic film.</p><p num="0021"> In the magnetic film of the above-mentioned magnetic film power sensor, the change in the end voltage in the current direction was measured as a magnetic resistance effect type magnetic film power sensor, but the so-called displacement of the output voltage in the width direction of the magnetic film is measured. It utilizes a planar hole effect type (PHE type) magnetic film power sensor, and may manage the charge and discharge of the secondary battery. In this case, it is necessary to secure a certain width of the magnetic film, but on the other hand, it is advantageous because the output of the bias voltage can be inherently avoided.</p><p num="0022"> The magnetic film preferably contains a metal magnetic material, a giant magnetoresistive (GMR) element, a tunnel magnetoresistive (TMR) element, a polymer magnetic material, and a semiconductor having a magnetoresistive effect as main components.</p>

<p num="0023"> According to the charge / discharge measuring device of the present invention, appropriate charge / discharge management can be performed by accurately measuring the capacity change of the secondary battery during charging / discharging.</p>

0024<figref num="1">It is a schematic perspective view which showed the structure of the magnetic film power sensor in this invention.</figref><figref num="2">It is a schematic diagram explaining the power measurement principle in the magnetic film power sensor shown in FIG.</figref><figref num="3">It is a schematic circuit diagram which showed the measurement system for DC power measurement.</figref><figref num="4">This is a modification of the connection circuit shown in Fig. 3. The magnetoresistive power sensors 1 and 1'are connected in series and installed so that the application direction of the external magnetic field H is reversed.</figref><figref num="5">It is a graph which shows the discharge characteristic of a battery.</figref><figref num="6">It shows an example of the change of the terminal voltage of the battery with different discharge currents.</figref><figref num="7">It shows the discharge characteristics of batteries in different temperature environments.</figref><figref num="8">It shows a circuit that monitors the amount of power movement (discharge amount, charge amount) when power is supplied to a load by a battery and when the battery is charged from an external power source.</figref><figref num="9">An example of a connection circuit using a magnetic film power sensor element as a wattmeter in the circuit of FIG. 8 is shown.</figref><figref num="10">Among the magnetic film power sensors, the connection circuit of the charge / discharge measuring device of the lead battery using the planar Hall effect (PHE type) type magnetic film power sensor 1 is shown.</figref><figref num="11">Charging power to the battery (black square mark (2)) obtained from the output (black circle (1): Vm) of the magnetic film power sensor 1 when charging in the connection circuit of Fig. 10 and the charging current I1 and the terminal voltage of the battery. )) Is a graph showing the time change.</figref><figref num="12">, The change in the integrated amount of the output (black circle (1)) of the magnetic film power sensor 1 and the integrated amount of the charging power in the connection circuit of FIG. 10 is shown.</figref><figref num="13">Power consumption under load (discharge power black) obtained from the output (black circle (1): Vm) of the magnetic film power sensor 1 "during discharge in the connection circuit of Fig. 10 and the terminal voltage of the discharge current I1 and load resistance R1. It is a time change with the square mark (2)).</figref><figref num="14">Integrated amount of output (Vm) of magnetic film power sensor 1 in the connection circuit of Fig. 10 (black circle (1): ΣVmt) and integrated amount of power consumption (discharge power) of load resistor R1 (black square mark (2) )) Shows how it changes.</figref><figref num="15">The output characteristics of the magnetic film power sensor 1 used in the connection circuit of FIG. 10 are shown.</figref><figref num="16">The time change between the integrated amount of output of the magnetic film power sensor 1 "during charging in the connection circuit of Fig. 10 (black circle (2): ΣVmt) and the integrated amount of charging power (black square mark (1)) is shown. There is.</figref><figref num="17">Integrated amount of magnetic film power sensor 1 "during discharge in the connection circuit of Fig. 10 (black circle (2): ΣVmt), integrated amount of charging power (black square mark (1)), output of magnetic film power sensor 1" It shows 85% of the accumulated amount (black triangle mark (3)).</figref><figref num="18">It shows the time change of the magnetic film power sensor 1 output (black circle (1) Vm), decrease in battery power (2), and battery terminal voltage (black square (3)) during discharge.</figref><figref num="19">This is a rewrite of Fig. 18 with the discharge end voltage 11 [V] set to 0 and the discharge start voltage (at full charge) set to 1 [V].</figref><figref num="20">Indicates the battery terminal voltage (black triangle mark (3)), magnetic film power sensor output (black circle mark (1)), and time change of electric energy (black square mark (2)) when charging and discharging are repeated. It is a thing.</figref><figref num="21">Ends discharging the battery terminal voltage (black triangle mark (3)), magnetic film power sensor output (black circle mark (1)), and time change of electric energy (black square mark (2)) when charging and discharging are repeated. It is rewritten with the hourly voltage 11 [V] set to 0 and the discharge start voltage (when fully charged) set to 1.</figref><figref num="22">It is a conceptual diagram which shows the usable electric energy.</figref><figref num="23">It is a figure which shows the structure of the battery system which concerns on this invention.</figref><figref num="24">It is a figure which shows the operation which confirms the charge electric energy in the battery system which concerns on this invention.</figref><figref num="25">It is a figure which shows the operation of discharging in the battery system which concerns on this invention.</figref><figref num="26">Barber pole type magnetoresistive effect type magnetic film The magnetic film in the power sensor is shown.</figref><figref num="27">An oblique conductor film and electrodes provided on the top of the magnetic film are shown.</figref><figref num="28">The relationship between the voltage V1 in the longitudinal direction and the magnetic field H is shown.</figref><figref num="29">A differential barber pole type magnetoresistive effect type magnetic film power sensor is shown. (A) is a photograph seen from above, and (b) is this magnetic film power sensor for measuring microstrip lines. The schematic diagram used is shown.</figref><figref num="30">It shows how the electrical resistance of a magnetic film changes due to the normal magnetoresistive effect.</figref><figref num="31">Due to the barber pole patterns with different inclinations, the magnetoresistive effect of the barber pole magnetic film shows the characteristics as if different bias magnetic fields are applied to the left and right sides of the magnetic film.</figref><figref num="32">The connection of the amplifier circuit of the differential type barber pole magnetoresistive type magnetic film power sensor is shown.</figref><figref num="33">The specific measurement system of FIG. 32 is shown.</figref><figref num="34">(a) shows the output characteristics between the AB terminals in Fig. 33, and (b) shows the output characteristics between the CB terminals in Fig. 33.</figref><figref num="35">The output voltage of the operational amplifier of FIG. 33 is shown.</figref><figref num="36">A schematic diagram of the measurement system when a bias magnetic field is applied in parallel with the long axis is shown.</figref><figref num="37">The output characteristics of the measurement system shown in FIG. 36 are shown.</figref><figref num="38">A measurement system of characteristics as a wattmeter when a load current (I1) is passed through a conductor film is shown.</figref><figref num="39">The output characteristics when a load current (I1) is passed through the conductor film without applying a bias magnetic field are shown.</figref><figref num="40">The output change due to the application of a magnetic field in the longitudinal direction of the device (longitudinal direction of the magnetic film) is shown.</figref><figref num="41">The measurement system when the bias magnetic field is applied is shown.</figref><figref num="42">The output characteristics of this magnetoresistive magnetic film power sensor when a bias magnetic field is applied are shown.</figref><figref num="43">It is a figure which shows the magnetic resistance response curve of the sensor used for DC power measurement.</figref><figref num="44">It is a figure which shows the magnetoresistive effect characteristic of a sensor B.</figref><figref num="45">It is a figure which shows the pattern of an element.</figref><figref num="46">It is a figure which shows the circuit of the experimental system of DC power measurement.</figref><figref num="47">It is a graph which shows the relationship between power consumption and sensor output.</figref><figref num="48">It is a figure which shows the result of the DC power measurement of the sensor B.</figref><figref num="49">It is a figure which shows the circuit at the time of charge / discharge.</figref><figref num="50">It is a figure which shows the result at the time of discharge.</figref><figref num="51">It is a figure which shows the result at the time of charging.</figref><figref num="52">It is a figure which shows the power measurement result in the case of alternating current.</figref><figref num="53">It is a figure which shows the magnetic resistance response curve when the sensor is made small.</figref><figref num="54">It is a figure which shows the power measurement result when the sensor is made small.</figref>

0025Hereinafter, specific embodiments and peripheral devices of the charge / discharge measuring device of the present invention will be described. First, a magnetic film power sensor used as a power measuring means in this charge / discharge measuring device will be described.

0026As shown in FIG. 1, the magnetic film power sensor 1 has a three-layer structure consisting of a conductor film 1a, an insulating film 1b, and a magnetic film 1c from the top. For example, the conductor film 1a, the insulating film 1b, and the magnetic film 1c are each composed of copper Cu, a polyimide substrate, and permalloy. A magnetic field is generated when the current I1 is passed through the conductor film 1a. At this time, since the magnetic field H is proportional to the current I1, it can be written as H = αI1.

0027When the magnetic field H is applied, the magnetoresistive effect occurs in the magnetic film 1c, and the resistance value changes. Since the amount of change in resistance value (ΔR) is proportional to the magnetic field H, it can be written as ΔR = βH. Finally, ΔR = αβI1, and it can be seen that the amount of change in resistance (ΔR) is proportional to the current flowing through the conductor film 1c.

0028FIG. 2 describes the power measurement principle of the magnetic film power sensor 1 shown in FIG. The input current is divided into the conductor film 1a and the magnetic film 1b of the magnetic film power sensor 1 arranged in parallel as currents I1 and I2, respectively. The load R1 (Load R1) to be measured for power is arranged in series on the conductor film 1a, and the resistor R2 for securing the current I2 is arranged in series on the magnetic film 1b. The resistance Rcu of the conductor film 1a and the resistance Rmr of the magnetic film shall be sufficiently smaller than the loads R1 and resistance R2. Then, the voltage V2 applied to the resistor R2 can be approximated to the input voltage Vin. Similarly, the voltage V1 applied to the load R1 can be approximated to Vin.

0029At this time, the amount of change in the voltage Vmr of the magnetic film 1b ΔVmr can be expressed as ΔVmr = I2 · ΔRmr, where ΔRmr is the amount of change in the resistance of the magnetic film. Since I2 Vin / R2 and ΔRmr = αβ · I1, the result is ΔVmr = (Vin / R2) αβ · I1.

0030From this, the power consumption under load can be expressed as V1 · I1 (R2 / αβ) ΔVmr. In this equation, since (R2 / αβ) in the first half is a constant, it can be seen that the amount of change in voltage applied to the magnetic film 1b ΔVmr is proportional to the power consumption. Therefore, by measuring the value of ΔVmr, the power consumption applied to the load can be known.

0031In the battery system and the charge / discharge measuring device of the present invention, such a magnetic film power sensor 1 is used as a power measuring means. This is because the magnetic film power sensor 1 has advantages such as small size, light weight, easy manufacturing, low self-consumption power, and output of electric energy as compared with a conventional mechanical integrated watt-hour meter or the like. That is, the magnetic film power sensor 1 can be used as a built-in sensor in various electronic devices, batteries, and electric devices, and is suitable for managing and controlling the charge / discharge of the battery.

0032Next, referring to FIG. 3, a measurement system for DC power measurement is shown. The magnetic film power sensor 1 includes a PHE type (planar Hall effect type) power sensor and a magnetoresistive effect type power sensor. The planar Hall effect type power sensor outputs a change in voltage in the direction perpendicular to the current when a current is passed through the magnetic film. The magnetoresistive power sensor outputs a change in voltage in the same direction as the current when a current is passed through the magnetic film.

0033Since the magnetoresistive power sensor can output a terminal voltage in the same direction as the current flowing through the magnetic film, the element can be formed into an elongated shape. However, there is essentially the problem of generating a large bias voltage. This has a problem that it is difficult to measure the power generated by the DC voltage. Ideally, the bias voltage can be suppressed in the case of the barber pole type described later. However, in reality, a slight bias voltage is generated due to the non-uniformity of the structure and the imbalance of the magnetic characteristics.

0034On the other hand, in the planar Hall effect type power sensor, a bias voltage is not generated in the output. However, since the width is required in the direction perpendicular to the current flowing through the magnetic film, there is a problem that it is difficult to arrange the width in the connection line of the circuit.

0035Therefore, the magnetoresistive power sensor cannot measure DC power by itself. The magnetoresistive power sensor needs to remove this bias voltage and obtain a voltage signal of only the change. In FIG. 3, in order to cancel the bias voltage, a resistor R3 having the same resistance value as the offset resistance of the magnetic film of the magnetic film power sensor 1 is connected in series, and the connection point between the magnetic film and the resistor R3 is grounded (center tap). By doing so, only the voltage change is detected.

0036A bias magnetic field is applied in a direction perpendicular to the direction of the current flowing through the magnetic film power sensor 1. Alternatively, the easy axis of magnetization of the magnetic film is guided in advance in a direction inclined with respect to the direction in which the current flows.

0037FIG. 4 is a modification of the connection circuit of FIG. 3, in which the magnetoresistive power sensors 1 and 1'are connected in series and installed so that the application direction of the external magnetic field H is opposite. In addition, the connection point between the magnetoresistive power sensors 1 and 1'is grounded. With this circuit configuration, the offset voltages cancel each other out, and the change due to the magnetic field H changes in the positive and negative directions. The output voltages at both ends where the magnetoresistive power sensors 1 and 1'are connected are differentially added together and become twice as large as in Fig. 3.

0038Therefore, according to the element connection methods shown in FIGS. 3 to 4, the problem of inability to measure DC power due to the influence of DC bias, which is a drawback of power measurement by the magnetoresistive power sensor, can be solved.

0039Next, the discharge characteristics of the battery will be described. FIG. 5 is a graph showing the discharge characteristics of the lead-acid battery. The vertical axis is the terminal voltage (Volt), and the horizontal axis is the electric energy (Wh). Line New is a non-deteriorated battery, and Line Old is the discharge characteristic of a deteriorated battery. As can be seen from this graph, the terminal voltage of the battery gradually decreases with discharge, and finally a sharp decrease in the terminal voltage is observed. In addition, the amount of power that the terminal voltage drops differs depending on the degree of deterioration of the battery.

0040The secondary batteries (rechargeable) targeted by the present invention include lead storage batteries, lithium ion batteries, nickel hydrogen batteries, and nickel cadmium batteries that are widely sold in many vehicles. For all batteries, there are basically differences in discharge characteristics due to the difference in deterioration shown in Fig. 5.

0041Figure 6 shows an example of changes in terminal voltage with different discharge currents. The vertical axis shows the terminal voltage of the battery, and the horizontal axis shows the remaining discharge capacity (%) of the battery. Line A shows the change in battery voltage when a 100 Ah battery is discharged at a constant current of 5 A (20 hour rate). Line B shows the change in battery voltage when a 100 Ah battery is discharged at 10 A (10 hour rate). Line C shows the change in battery voltage when a 100Ah battery is discharged at 20A (5 hour rate). Line D shows the change in battery voltage when a 100Ah battery is discharged at 100A (1 hour rate).

0042From this figure, it can be seen that the state of change in the terminal voltage differs depending on the discharge current. Further, even when the terminal voltage is the same, it can be seen that the remaining discharge capacity (residual power) of the battery differs depending on the discharge history up to that point.

0043In addition, FIG. 7 shows the discharge characteristics of the battery in different temperature environments. The vertical axis shows the battery voltage (2.4V to 4.4V), and the horizontal axis shows the capacity (0 to 2500mAh). It shows the discharge characteristics when it is a cylindrical 18650 size, the nominal capacity is 2000mAh, and the discharge current is 0.2C (400mA). In addition, each line in the graph shows the temperature environment during discharge. It can be seen that the change in terminal voltage differs depending on the temperature environment.

0044From the above, in the method of predicting the remaining power of a battery by reading the terminal voltage of the battery, which has been generally performed in the past, the drop curve of the battery terminal voltage differs depending on the usage environment and usage state of the battery. Therefore, it can be seen that it is not possible to accurately measure the remaining power of the battery. Therefore, the present charge / discharge measuring device for accurately measuring the remaining power amount of the battery is exemplified below.

0045Figure 8 shows a circuit that monitors the amount of power transfer (discharge amount, charge amount) when power is supplied to the load by the battery and when the battery is charged from an external power source. During charging and discharging, the direction of current flow changes positively and negatively. However, since the polarity of the terminal voltage of the battery does not change, if the output of the wattmeter is positive during charging, a negative output is obtained during discharging, and if the output signal during charging and discharging is integrated by the integrator circuit, the remaining power of the battery is obtained. The amount is obtained. Since this wattmeter is bidirectional, the remaining battery level can be obtained with a very simple electric circuit.

0046FIG. 9 is a diversion example of FIG. An example of a connection circuit using the magnetic film power sensor elements 1 and 1'shown in FIG. 4 is shown in the part of the circuit of FIG. 8 as a wattmeter. Here, the magnetic film power sensors 1 and 1'use a magnetoresistive power sensor that measures the voltage displacement of the magnetic film in the current direction. In this connection circuit, a rectifier circuit 3, a charger 4, and a changeover switch 5 are added to manage charge / discharge power.

0047The rectifier circuit 3 converts an alternating current into a direct current, and a bridge circuit is a simple configuration example. Further, the charger 4 generates an alternating current, and although not shown, the charger 4 is connected to an external power source or a drive device. When the charger 4 generates a DC voltage, the rectifier circuit 3 is unnecessary.

0048In the case of a magnetoresistive power sensor, a large DC bias voltage is output when a DC voltage is handled in the connection configuration of a single magnetic film power sensor element. Therefore, in order to solve this problem, in the connection circuit of FIG. 9, two magnetoresistive power sensor elements 1 and 1'are connected in series, and the contacts are grounded. With this configuration, the bias output voltage is canceled by applying a magnetic field due to the current in the opposite direction and differentially adding the DC bias voltages. As a result, DC power can be measured even by using a magnetoresistive magnetic film power sensor.

0049First, when the changeover switch 5 is connected to the load R1, the power consumption of the battery, which is a DC power supply, can be detected as described with reference to FIG. On the other hand, when the changeover switch 5 is connected to the charger 4, the charger 4 can detect the power charged in the battery.

0050Therefore, in the case of the connection method shown in FIG. 9, it is possible to monitor the amount of power transfer (discharge amount, charge amount) between the case where the battery supplies power to the load R1 and the case where the battery is charged by an external power source. it can.

0051Further, the cancellation of the bias output voltage may be subtracted by diverting the connection circuit of FIG. 3 and generating a voltage equivalent to the DC bias voltage generated by the magnetic film power sensor 1 by the dummy resistor R2.

0052Further, as the magnetoresistive power sensor, a so-called barber pole type magnetic film power sensor may be used. The barber pole type magnetic film power sensor and the connection circuit using the same will be described separately at the end of this specification with reference to FIGS. 26 and 26.

0053Next, FIG. 10 shows a connection circuit of a lead battery charge / discharge measuring device using a planar Hall effect (PHE type) type power sensor 1 of the magnetic film power sensors. Planer Hall effect type power sensor. 1 "measures the voltage displacement of the magnetic film 1" c in the width direction (direction perpendicular to the current). The planar Hall effect type magnetic film power sensor 1 "essentially does not generate a bias voltage. ..

0054Therefore, it is not necessary to provide a configuration for canceling the bias voltage in the connection circuit of FIG. 10 as in the connection circuit of FIG. Discharge current (load current) or charge current in this connection circuit I₁Flow in opposite directions when discharging or charging. Also, I₂Always monitor the battery voltage with magnetic film 1 c and resistor R₂Is flowing to. In the experiment shown below, the charging current I₁Is constant at 2A, and the discharge current is the load R₁Current I flowing through (= 5Ω)₁= 2.4A ~ 2.2A.

0055FIG. 11 shows the charging power to the battery (white) obtained from the output (black circle (1): Vm) of the magnetic film power sensor 1 when charging in the connection circuit of FIG. 10, the charging current I1, and the terminal voltage of the battery. It is a graph showing the time change of the square mark (2): W). The left vertical axis is the output Vm (mV) of the magnetic film 1c , the right vertical axis is the charging power (W), and the horizontal axis is the horizontal axis. Time (min). Vm is the magnetic film power sensor output. As is clear from FIG. 11, the magnetic film power sensor output (1) and the charging power (2) match very well.

0056FIG. 12 shows changes in the integrated amount (black circle (1): ΣVmt) of the output (magnetic film power sensor output Vm) of the magnetic film 1c and the integrated amount of charging power in the connection circuit of FIG. The left vertical axis is ΣVmt (mV · h), the right vertical axis is the charging power amount (W · h), and the horizontal axis is the time (min). Magnetic film power sensor 1 as in Fig. 11. It can be seen that the integrated amount of output (1) and the integrated amount of charging power (white square (2)) match very well.

0057FIG. 13 shows the output (black circle (1): Vm) and discharge current I of the magnetic film power sensor 1 during discharge in the connection circuit of FIG.₁And load resistance R₁It is a time change from the power consumption (discharge power white square mark (2)) under the load obtained from the terminal voltage of. The left vertical axis is Vm (mV), the right vertical axis is power consumption (W), and the horizontal axis is time (min). Compared to the charging in Fig. 11, the change in the output (1) of the magnetic film 1 c for several minutes from the start of discharging is slightly different (Vm drops).

0058On the other hand, load resistance R₁It can be seen that this is in good agreement with the change in power consumption (2) in. The output of the magnetic film power sensor 1 "was about half that of the case of charging (Fig. 11). This is slightly in the direction of the easy axis of the magnetic film 1" c and the direction of the flowing current. There is a deviation, and it is the difference in gain due to the change in the direction of the current between charging and discharging.

0059FIG. 14 shows the integrated amount (black circle (1): ΣVmt) of the output (Vm) of the magnetic film power sensor 1 in the connection circuit of FIG. 10 and the load resistance R.₁It shows how the integrated amount of power consumption (discharge power) (white square mark (2)) changes in. The left vertical axis is the integrated amount ΣVmt (mV · h), the right vertical axis is the power consumption (W · h), and the horizontal axis is the time (min). As in FIG. 12, it can be seen that the integrated amount of output (1) of the magnetic film power sensor 1 and the integrated amount of power consumption (2) are very well matched.

0060Next, FIGS. 15 (a), 15 (b), and (c) show the output characteristics of the magnetic film power sensor 1 used in the connection circuit of FIG. 10. FIG. 15 (a) shows the characteristics at the time of discharge. The vertical axis is ΣVmt (V min) and the horizontal axis is power consumption (W h). Fig. 15 (b) shows the characteristics during charging, and the vertical axis is ΣVmt (V min). Yes, the horizontal axis is the amount of charging power (W · h). The deviation from the approximate straight line during charging and discharging was 6% during discharging and 2% during charging. The index on the vertical axis is 10.^-6Is.

0061FIG. 15 (c) is a re-plot of FIGS. 15 (a) and 15 (b) on the same vertical axis. Since the charging current and the discharging current have different directions, the polarity of the output voltage Vm of the magnetic film power sensor 1 changes between charging and discharging. Here, charging is positive and discharging is negative. The reason why the slope of ΣVmt, which is the integrated value, changes during charging and charging is that the gain changes depending on the direction of the current during charging and discharging.

0062FIG. 16 shows the time between the integrated amount of the output of the magnetic film power sensor 1 when charging in the connection circuit of FIG. 10 (black circle (1): ΣVmt) and the integrated amount of charging power (white square mark (2)). The change is shown. This is the same as in Fig. 12. In addition, Fig. 17 shows the integrated amount of the magnetic film power sensor 1 "during discharge (black circle (2): ΣVmt) and discharge power (white square mark (1)). ), And 85% of the integrated amount of the output of the magnetic film power sensor 1 (black triangle mark (3)). This is the same as in FIG.

0063Batteries were charged and discharged repeatedly, with the charging end voltage set to 14 [V] and the discharging end voltage set to 11 [V]. The amount of charging power was calculated from the charging current and the terminal voltage of the battery, and was 24.519 [Wh]. The amount of discharge power was calculated from the discharge current and the load terminal voltage, and was 21.0 [Wh]. From this, the charging efficiency was about 85%. It is shown that the increase / decrease of the electric power from the battery at the time of charging / discharging can be accurately obtained in consideration of the charging efficiency.

0064Fig. 18 shows the time change of the magnetic film power sensor 1 output (black circle (1) Vm), decrease in battery power (2), and battery terminal voltage (white square (3)) during discharge. The left vertical axis shows the electric energy (W · h) of the battery and the output Vm (mV) of the magnetic film power sensor 1 , the right vertical axis shows the terminal voltage (V) of the battery, and the horizontal axis shows the time (min). .. It can be seen that the time change of the electric energy of the battery (2) and the time change of the terminal voltage of the battery (3) are clearly different.

0065FIG. 19 is a rewrite of FIG. 18 with the discharge end voltage 11 [V] set to 0 and the discharge start voltage (at full charge) set to 1 [V], and is the output (black circle) of the magnetic film power sensor 1 . (3): Vm), decrease in battery power (white triangle mark (2)), time change of battery terminal voltage (white square mark (1)). Vertical axis is standardized Vm , Battery power, battery terminal voltage (both%), horizontal axis is time (min). Battery terminal voltage is the voltage at the start of discharge (when fully charged) (white square mark (1)) ) Has decreased to 50%, indicating that 93% of the charged power (white triangle (2)) has already been consumed, leaving only 7% of the power.

0066Figure 20 shows the terminal voltage of the battery when charging and discharging are repeated (cross mark (3)), the integrated value of the output of the magnetic film power sensor ΣVmt (black circle mark (1)), and the amount of power (white square mark (2)). ) And the elapsed time are shown. This battery has a long history of use and is a so-called deteriorated battery. The left vertical axis is the integrated value of the battery power (W h) and the output of the magnetic film power sensor 1 ΣVmt (mV h), the right vertical axis is the battery terminal voltage Vbat (V), and the horizontal axis is the time ( It represents min). This graph shows that charging and discharging were repeated 4 times.

0067Charging and discharging are repeated with the charging end voltage being 14 [V] and the discharging end voltage being 11 [V]. It can be seen that the time to reach the charging end voltage of 14 [V] becomes shorter and the amount of charging decreases with each repetition (2). Therefore, the amount of discharge power is also small. In addition, the state of decrease in terminal voltage (3) is different each time, and it is clear that it does not reflect that the amount of charging power is decreasing.

0068Fig. 21 shows the terminal voltage of the battery when charging and discharging are repeated (cross mark (3)), the integrated value of the output of the magnetic film power sensor (black circle mark (1)), and the time change of the electric energy (white square mark (2)). )) Is re-plotted with the discharge end voltage 11 [V] set to 0 and the discharge start voltage (at full charge) set to 1. The vertical axis is the standardized Vm, the electric energy of the battery, and the terminal voltage of the battery (all%), and the horizontal axis is the time (min). When charging, the voltage change from the charging start voltage to the charging end voltage (14V) is standardized to 0 to 100%, and when discharging, the discharge end voltage (11V) is displayed as 100 to 0%. This is a re-plot of Figure 20.

0069It can be seen that even if charging and discharging are repeated, the integrated value ΣVmt (1) of Vm changes in the same way as the change in the electric energy (2) during charging and discharging from the battery each time. However, it can be seen that the terminal voltage (3) changes regardless of the electric energy (2).

0070What should be noted here is the time from the start of charging until the terminal voltage of the battery reaches 14 (V) and the time from the start of discharging until the terminal voltage of the battery reaches 11 (V). Is almost equal at each charge / discharge characteristic. Further, as shown in FIGS. 11 and 13, if the battery is charged and discharged at a constant current, it shows a substantially constant value with respect to time regardless of the remaining power amount of the battery and the terminal voltage.

0071These facts indicate that the time until discharge can be estimated from the power consumption at a predetermined current at the start of discharge. That is, it means that the remaining power amount of the battery can be visualized. That is, the charging time when charging with a constant current from the charging start voltage to the charging end voltage is regarded as the discharge time when discharging with that current.

0072See FIG. FIG. 22 (a) shows a schematic diagram of FIG. 11 (during charging). The vertical axis is the output of the magnetic film power sensor, and the horizontal axis is time. At this time, the charging end time is T10. FIG. 22 (b) shows a schematic diagram of FIG. 13 (during discharge). The vertical axis is the output of the magnetic film power sensor, and the horizontal axis is time.

0073At this time, the power consumed is considered to be constant regardless of time. The discharge time is considered to be the same as the charge time Tc. Then, the part of the area S, which is the product of the initial power consumption Vm0 at the time of discharging and the charging time Tc, can be regarded as the usable power amount of the battery. From FIGS. 20 and 21, the usable electric energy S decreases as it deteriorates.

0074However, the amount of usable power can be estimated without knowing the degree of deterioration of the battery (that is, without knowing the battery usage history). A battery system having such a function is very useful.

0075As a specific configuration capable of managing charge / discharge power, the charge / discharge measuring devices shown in FIGS. 8 and 9 have already been shown. However, by providing a charge / discharge measuring device and a control unit that controls the changeover switch 5 in FIG. 9, it is possible to realize a battery system capable of displaying the remaining power amount.

0076FIG. 23 shows the configuration of a battery system using this principle. The battery system 30 includes a secondary battery 32, a magnetic film power sensor 34, a battery voltmeter 36, an inspection resistance 40, an inspection switch 42, a connection switch 44, and a control unit 46. Further, the ammeter 38 and the display unit 48 may be included.

0077The secondary battery 32 is not particularly limited as long as it can be charged and discharged. Further, a plurality of secondary batteries may be connected in series or in parallel. The magnetic film power sensor 34 includes a magnetic film 29, a conductor film 28, a sensor voltmeter 27, and a sensor resistor 26. The magnetic film 29 may be a magnetoresistive effect type magnetic film or a planar Hall effect type magnetic film. As described above, in the case of the magnetoresistive effect type, it is desirable to use an element shape or a center tap configuration so that the bias voltage can be canceled. Note that FIG. 23 shows the case where a planar Hall effect type magnetic film is used.

0078The magnetic film 29 is used so as to be superimposed on the conductor film 28. This is to fix the positional relationship with the current flowing through the conductor film 28. At this time, it is desirable to match the direction of the current flowing through the conductor film 28 with the direction of the easy axis of magnetization of the magnetic film 29. If it is deviated, as shown in FIG. 20, the gain of the magnetic film power sensor 34 differs between charging and discharging. Further, one ends of the magnetic film 29 and the conductor film 28 are connected to each other. Regarding the relationship between the magnetic film 29 and the conductor film 28, it can be said that the magnetic film 29 is arranged adjacent to the connecting line between the secondary battery 32 and the external electrodes 30t1 and 30t2.

0079The magnetic film 29 does not have to be a single film. As shown in FIGS. 4 and 27, it may be composed of a plurality of magnetic films.

0080A sensor voltmeter 27 is connected to the magnetic film 29. Since the planar Hall effect type is shown in FIG. 23, the voltage in the direction perpendicular to the current flowing through the magnetic film 29 is measured. When a magnetoresistive magnetic film 29 is used, the voltage across the magnetic film 29 in the direction of flow is measured. The magnetic film 29 is connected to one end of the sensor resistor 26. The sensor resistor 26 is a resistor having a sufficiently large resistance value. This is to ensure that a substantially constant current flows regardless of the value of the current flowing from the battery.

0081The connection of the sensor voltmeter 27 changes depending on the shape and configuration of the magnetic film 29. Therefore, measuring the voltage of the sensor voltmeter 27 means measuring the resistance of the magnetic film 29, which changes depending on the magnetic field generated by the current of the circuit to be measured, so that it can be used as the output voltage of the magnetic film power sensor.

0082The battery voltmeter 36 measures the terminal voltage of the secondary battery 32. The ammeter 38 also measures the current flowing through the battery system 30. In either case, the internal configuration is not limited as long as the voltage value and current value can be measured or converted.

0083The inspection resistor 40 is a resistor for inspecting how much electric power is stored in the secondary battery 32 after charging. Further, the inspection switch 42 is a switch for connecting the inspection resistor 40 and the secondary battery 32 when inspecting the stored electric energy. Further, the connection switch 44 is a switch that cuts off the connection with the outside. Both the inspection switch 42 and the connection switch 44 are controlled by the control unit 46, which will be described later.

0084The control unit 46 is a computer composed of an MPU (Micro Processor Unit) and a memory. The timer 46t and the display unit 48 are connected to the control unit 46. Further, the control unit 46 is connected to a sensor voltmeter 27, a battery voltmeter 36, an ammeter 38, an inspection switch 42, and a connection switch 44.

0085The control unit 46 receives the signal St from the timer 46t. This is to measure the elapsed time. Therefore, the signal St is time information. Further, even if the control unit 46 transmits the measurement start signal Cts (not shown) to the timer 46t, the measurement end signal Ctt (not shown) is transmitted, and the elapsed time is known from the signal St output by the timer as a result. Good. The signal St in this case is the time information created by the timer 46t.

0086In any case, by having the timer 46t, the control unit 46 can acquire the time between predetermined times. In other words, it can be said that the timer 46t measures the time related to the charging time and the discharging time.

0087Further, since the control unit 46 can calculate the residual power amount as described later, it sends it as a signal Sd to the display unit 48. The display unit 48 may be a display composed of eight segments, or may be a display using a liquid crystal or an organic EL. Moreover, you may simply turn on a predetermined light.

0088Further, the control unit 46 is connected to the sensor voltmeter 27, and receives the voltage in the magnetic film 29 as a signal Svm from the sensor voltmeter 27. The control unit 46 is also connected to the battery voltmeter 36 and the ammeter 38, and receives the voltage between the battery terminals as a signal Svb and the current value as a signal Si, respectively.

0089Further, the control unit 46 is also connected to the connection switch 44 and the inspection switch 42, and can instruct the opening / closing or change of the connection point by the instruction Ccn and the instruction Cck.

0090Next, the overall connection relationship will be described. The external terminals 30t1 and 30t2 are terminals for connecting the battery system 30 and an external device. One pole of the secondary battery 32 (positive electrode in FIG. 23) is connected to the external terminal 30t1, and the other electrode (negative electrode in FIG. 23) is connected to the external terminal 30t2. A conductive film 28, an ammeter 38, an inspection switch 42, and a connection switch 44 are connected in series between the positive electrode and the external terminal 30t1.

0091The conductive film 28 and the ammeter 38 are arranged on the positive electrode side of the inspection switch 42, and the connection switch 44 is arranged on the external terminal 30t1 side of the inspection switch 42. The inspection switch 42 switches the connection between the positive electrode side and one end of the connection switch 44 or the inspection resistor 40. The other end of the inspection resistor 40 is connected between the external terminal 30t2 and the negative electrode.

0092A battery voltmeter 36 is connected between the two poles of the secondary battery 32. A magnetic film 29 and a sensor resistor 26 are connected in series between the two poles of the secondary battery 32. As described above, the magnetic film 29 and the conductive film 28 are overlapped with each other. The sensor voltmeter 27 is connected so as to measure the voltage of the magnetic film 29. As described above, the sensor voltmeter 27 has a different connection point to the magnetic film 29 between the magnetoresistive effect type and the planar Hall effect type. As for the above connection relationship, the connection order may be changed as long as the purpose of the connection does not change.

0093Further, in the above configuration, the magnetic film power sensor 34 is both a discharge power measuring means and a charging power measuring means.

0094The operation of the battery system 30 including the above configuration will be described. With reference to FIG. 23, at the time of charging, the charger 50 is connected to the external connection terminals 30t1 and 30t2. In Fig. 23, a constant current power supply is connected. The inspection switch 42 is connected to the external terminal 30t1 side. When the control unit 46 starts charging, the connection switch 44 is connected to the external charger 50 by the instruction Ccn, and a current is passed to the battery system 30 from the outside.

0095Charging may be started by an instruction from the outside, or as shown in FIG. 8, in the case of a configuration in which the charger 50 can be connected at any time by a switch, the battery voltmeter 36 is monitored and the voltage becomes a predetermined voltage. Then you may start charging. The battery voltage at which charging starts is called the charging start voltage (for example, 11V).

0096When charging in the case of FIG. 23, the charging current Icg flows in the direction of the arrow. The current Icg flows through the conductor film 28. The magnetic field generated at that time becomes an external magnetic field for the magnetic film 29, and a voltage due to the planar Hall effect is generated in the magnetic film 29. The current Icg flowing through the conductor film 28 flows in the secondary battery 32, and returns to the charger 50 from the external terminal 30t2 again.

0097Further, a part of the current flowing through the conductive film 28 also flows through the magnetic film 29. However, since the sensor resistance 26 is a large value, the current Imc passing through the magnetic film 29 can be considered to be constant.

0098When the control unit 46 starts charging, it first acquires a time from the timer 46t and sets this as the charging start time. Then, when the battery voltmeter 36 reaches a predetermined voltage (for example, 14V), charging is terminated. This is called the charge end voltage. The end of charging may be realized by sending an instruction Ccn from the control unit 46 to the connection switch 44 and disconnecting the connection switch 44. When charging is completed, the time is acquired from the timer 46t and used as the charging end time. The control unit 46 calculates the charging time Tc from the charging start time and the charging end time.

0099While charging, the control unit 46 measures the value Vm of the sensor voltmeter 27 for each minute time ΔT, calculates and integrates (adds) the electric energy ΔWh in the minute time ΔT. The voltage Vm of the sensor wattmeter 27 is a value indicating charging power. That is, the product of the voltage Vm and the minute time ΔT indicates the electric energy ΔWh. Therefore, the electric energy ΔWh may be a value ΣVmt obtained by integrating the product of the sensor voltage Vm and the time. Of course, the sensor voltage Vm may be converted into electric power and the product with time may be integrated.

0100The control unit 46 continues to calculate the integrated value ΣVmt until the battery voltmeter 36 reaches the charging end voltage. At this time, the display unit 48 may display a display indicating that the battery is currently being charged or the current integrated value ΣVmt.

0101When the battery voltmeter 36 reaches the charging end voltage, the control unit 46 sends an instruction Ccn to the connection switch 44 to disconnect from the charger 50. Further, the time from the start of charging to the end of charging is calculated as the charging time Tc. At this time, the display unit 48 may display a display indicating the end of charging and a charging time Tc.

0102Next, refer to FIG. 24. When charging is completed, the control unit 46 sends an instruction Cck to the inspection switch 42 and sends a current Ick to the inspection resistor 40. At this time, the current Ick flows from the positive electrode to the negative electrode of the secondary battery 32 through a circuit with the inspection resistor 40 as a load. Here, the value of the sensor voltmeter 27 by the flowing current Ick is read as the initial power consumption Vm0 (see FIG. 22 (b)). Then, the value obtained by integrating the charging time Tc and the initial power consumption Vm0 is defined as the charging power amount Wcg. This corresponds to the area S in FIG. 22 (b).

0103After reading the initial power consumption Vm0, the inspection switch 42 may be immediately switched to the external terminal 30t1 side. The reason why the current continues to flow through the inspection resistor 40 is that power is lost.

0104As shown in FIG. 21, the value of this charging electric energy Wcg changes depending on the degree of deterioration of the secondary battery. That is, it is possible to know the amount of electric power stored in the charged secondary battery 32 without knowing the usage history of the secondary battery. The control unit 46 displays this charging electric energy Wcg as the remaining electric energy on the display unit 48. At this time, the display should be at least "display related to the absolute value of the charging power amount Wcg".

0105The degree of deterioration of the secondary battery 32 changes depending on the usage history. This means that even if the secondary battery has the same standard, the capacity when fully charged will change. That is, in the case of a gasoline-powered vehicle, it means that the capacity of the gasoline tank itself is reduced. In such a situation, displaying the charge amount as a percentage does not make much sense as long as the amount of power when fully charged is unknown.

0106On the other hand, if the display related to the absolute value of the charging power Wcg is displayed, the user can also know the change of the charging power Wcg itself. The display related to the absolute value of the charging power Wcg may be, for example, the mileage and the traveling time when the vehicle travels by using electricity at a constant speed. It may also be a ratio to the recommended amount of power to be maintained under normal usage conditions. If it is a robot, it may be the activity time when converted into a predetermined work.

0107The charging power Wcg may be a value converted into actual power, or may be ΣVmt (product of voltage and time) obtained by integrating the product of the sensor voltage Vm and time during the charging time. Further, the control unit 46 only needs to calculate the charging electric energy Wcg, and does not have to actually display the display on the display unit 48. For example, the charging electric energy Wcg may be simply output as a signal.

0108As described above, when charging the secondary battery 32 via the pair of external terminals (30t1, 30t2), the control unit 46 measures the charging time Tc from the charging start voltage to the charging end voltage, and the charging ends. After that, the current Ick is passed through the inspection resistance 40 by the inspection switch 42, and the charging power amount, that is, the residual power amount is calculated based on the initial power consumption Vm0 consumed by the inspection resistance 40 and the charging time. It is desirable to determine the value of the inspection resistor 40 in advance so that the current Ick is almost the same as the current Icg at the time of charging.

0109Next, referring to FIG. 25, the control unit 46 connects the connection switch 44 to the external terminal 30t1 side. When the load 52 is connected to the battery system 30, external terminal 30t1, load 52, external terminal 30t2, negative electrode and current Id flow from the positive electrode of the secondary battery 32. While the current Id due to the load 52 is flowing, the control unit 46 measures the value Vm of the sensor voltmeter 27 for each minute time ΔT, and obtains the discharge power amount as ΔT · Vm. Then, the discharge power amount ΔT · Vm is subtracted from the charge power amount Wcg to obtain a new charge power amount Wcg.

0110The control unit 46 causes the display unit 48 to display the reduced charge electric energy Wcg. Also in this display, the display related to the absolute value of the charging electric energy Wcg may be performed. This is the amount of residual power. The user can grasp the remaining charge power amount Wcg on a scale such as time or work amount according to the use. Of course, along with such a display, a percentage display with respect to the charging power amount Wcg immediately after the end of charging may be performed.

0111In the above power management, the part of the magnetic film power sensor 34 can measure the charge and discharge powers even if the magnetic film 29 is not used, and if the discharge power can be measured, it can be realized. Can be done. However, if it is provided integrally with the battery system 30, the power sensor 34 using the magnetic film 29 can measure the power only by measuring the voltage of the sensor voltmeter 27, so that it can be miniaturized. Suitable.

0112As described above, the charging power amount Wcg was obtained from the charging time Tc and the initial power consumption Vm0 because the gain of the magnetic film power sensor 34 was different between charging and discharging. Therefore, when the magnetic film power sensor 34 can be used even when discharging in the same current direction as when charging, or when the magnetic film 29 and the conductor film 28 of the magnetic film power sensor 34 can be precisely set, when charging and discharging. If it can be considered that the gains of the magnetic film power sensors 34 of the above are equal, ΣVmt, which is the integrated power amount at the time of charging, may be set as the charging power amount Wcg without measuring the charging time Tc.

0113If the gain of the magnetic film power sensor 34 can be the same during charging and discharging, the inspection resistor 40 and the inspection switch 42 are unnecessary. Further, in order to use the magnetic film power sensor 34 in the same current direction as during charging, a switch for changing the current path between charging and discharging is required separately.

0114The control unit 46 integrates the charging power for each minute time from the charging start voltage to obtain ΣVmt. When the charging end voltage is reached, disconnect the connection switch 44 and set ΣVmt to the charging power amount Wcg. When the battery system 30 is connected to the load, the power consumption in the load is subtracted from the charge power amount Wcg in the same manner as described above to obtain a new charge power amount Wcg. This charging electric energy Wcg is the residual electric energy.

0115The control unit 46 performs "display related to the absolute value of the charging power amount Wcg", so that the user can know the amount of power that can be substantially used of the secondary battery 32. When a load is connected, the power consumption may be subtracted from the charging power Wcg as described in FIG. 25.

0116Further, when the gains of the magnetic film power sensor 34 during charging and discharging can be regarded as equal in this way, it is not necessary to measure the charging time Tc, so that it is not necessary to perform charging under the condition of a constant current. For example, in the case of quick charging, the charging time may be shortened by periodically passing an overcurrent.

0117Even in such a case, the amount of residual power can be estimated by measuring the amount of power during charging with the magnetic film power sensor 34 and the timer 46t, obtaining ΣVmt, and using it as the amount of charging power Wcg. In the above description, the battery system 30 includes the secondary battery 32, the magnetic film power sensor 34, and the control unit 46, but a portion other than the secondary battery may be used as a charge / discharge measuring device.

0118From the above, it is understood that it is more useful to manage the charge / discharge of the secondary battery with the magnetic film power sensor (thin film wattmeter) than to manage with the terminal voltage of the battery. It is also understood that the magnetic film power sensor is the best for managing a secondary battery in which the amount of chargeable power, that is, the amount of usable power decreases with each repetition of charging and discharging (while in use).

0119From the above results, it can be concluded that the charge / discharge measuring device of the present invention using the magnetic film power sensor is most suitable for application to smart grids, smart batteries and the like. Very useful for avoiding power problems.

0120Here, an example of the above-mentioned barber hole type magnetic film power sensor and the connection circuit of the main charge / discharge measuring device using the same will be described.

0121FIG. 26 shows a magnetic film in a barber pole type magnetoresistive type magnetic film power sensor. FIG. 27 shows an oblique conductor film and electrodes provided on top of the magnetic film (hereinafter referred to as barber pole electrodes). Hereinafter, a magnetic film integrated with a magnetic film and an oblique conductor (barber pole electrode) formed on the magnetic film is referred to as a "barber pole magnetic film".

0122FIG. 26 shows an image diagram showing the current direction and the magnetization direction when the barber pole magnetic film (magnetic field sensor) 1 is viewed from above. Further, FIG. 27 shows an oblique conductor and an electrode pad provided on the upper part of the magnetic film 1. (a) shows an overall view, and (b) shows a magnified view of the circled portion in (a). The conductor film 1c and the magnetic film 1a shown in FIGS. 26 to 27 correspond to the conductor film 1c and the magnetic film 1a of the magnetic sensor unit 1 of FIG. 1, respectively.

0123A permalloy (NiFe) film having a length of 30 mm, a width of 1 mm, and a film thickness of about 0.1 μm is used as the magnetic film. As shown in FIGS. 26 to 27, the barber pole magnetic film is provided with an oblique conductor film 1c (corresponding to the uppermost conductor film 1c in FIG. 4) in the width direction (vertical direction of the paper surface) of the magnetic film, and is Cu. Is used. The conductor film 1c has a width of 0.5 mm, a length of 3 mm, a film thickness of 0.1 μm, and a distance between the conductor film and the conductor film of 1 mm (see FIG. 27).

0124When the magnetic sensor 1 shown in FIGS. 26 to 27 is used as the magnetic film power sensor, it is necessary to pass a current through the magnetic film 1a. At this time, by providing the conductor film 1c, the current has a property of flowing in a direction smaller than the electric resistance (see FIG. 26). First, the electrical resistance of the conductor film (Cu film) 1a is about 10 times smaller than that of the magnetic film (permalloy film) 1a.

0125Therefore, the electric resistance of the current is smaller when the distance between the conductor film and the conductor film is shorter and when the current flows through the conductor film 1c than when the current travels straight in the longitudinal direction of the magnetic film 1a. Since the magnetization direction (magnetization easy direction) is induced in the magnetic film in advance by shape anisotropy and induction anisotropy, an angle is generated between the direction in which the current flows and the magnetization direction.

0126Therefore, as shown in FIG. 28 (b), the magnetoresistive characteristic of the barber pole magnetic film 1a shows the characteristic as if the magnetic field-resistive characteristic due to the normal magnetoresistive effect is biased by the bias magnetic field. .. Note that FIG. 28 shows the relationship between the voltage V1 in the longitudinal direction and the magnetic field H, and FIG. 28 (a) corresponds to FIG. 2 and shows the normal magnetoresistive effect, and the output voltage V1 with respect to the magnetic field H is a treatment function. It is understood that the bias magnetic field is unnecessary because (b) shows the magnetoresistive effect of the barber pole magnetic film, while it is necessary to apply a bias magnetic field in order to obtain linear characteristics in order to form it. Yeah.

0127FIG. 29 shows a differential type barber pole type magnetoresistive effect type magnetic film power sensor, and a schematic diagram using this magnetic film power sensor for measuring a microstrip line is shown.

0128Figure 30 shows how the electrical resistance of the magnetic film changes due to the normal magnetoresistive effect. Due to the barber pole patterns with different inclinations, the magnetoresistive effect of the barber pole magnetic film shows the characteristics as if different bias magnetic fields are applied to the left and right sides of the magnetic film (Fig. 31). As shown in FIG. 31, the left barber pole magnetic film 1 shows the characteristic B that is negatively biased with respect to the applied magnetic field, and the right barber pole magnetic film 1 shows the characteristic A that is positively biased. ..

0129When these different barber pole magnetic films 1 and 1 are connected in series and a magnetic field is applied in the same direction, for example, from left to right, the resistance of each barber pole magnetic film changes so as to decrease on the one hand and increase on the other. .. If they can be output differentially, only changes can be extracted with the magnetic field zero point as the operating point, as shown in the figure below of FIG. 31.

0130Further, when the magnetic film 1 having a normal magnetoresistive effect is used, it is necessary to apply a large bias magnetic field as shown in FIG. 30 and set the operating point at a place having good linearity. However, as shown in FIG. 31, by using the differential type barber pole magnetic film, the operating point can be moved to a zero magnetic field, and the change in electrical resistance due to the magnetic field can be doubled. It is advantageous in that the magnetic film power sensor can be operated in a bias-free magnetic field.

0131Figure 32 shows the connection of the amplifier circuit of the differential type barber pole magnetoresistive type magnetic film power sensor 1. By grounding the B terminal in FIG. 32 and adding the electric signals from the A terminal and the C terminal with an operational amplifier, it is possible to obtain an electric signal that outputs only a change in the magnetic field without a bias voltage.

0132Figure 33 shows the measurement system. All resistance values of the amplifier are 2 kΩ, and the amplification gain is 1.

0133Next, the output characteristics of the magnetic film power sensor 1 of the barber pole magnetic film with respect to a uniform external magnetic field were measured. FIG. 34 (a) shows the output characteristics between the AB terminals of FIG. 33, FIG. 34 (b) shows the output characteristics between the CB terminals of FIG. 33, and FIG. 35 (c) shows the output voltage of the operational amplifier of FIG. 33. In these figures, the vertical axis is the output (V), and the horizontal axis is the magnetic field applied from the outside (magnetic field by the Helmholtz coil in FIG. 33). Regarding the output characteristics between the AB terminals shown in Fig. 34 (a), the output offset between AB is 742 [mV], the output change between AB is 4 [mV], and the output change rate of AB is 0.42 [%]. , The resistance change rate is 0.0031 / 0.742 * 100 = 0.42 [%].

0134Regarding the output characteristics between the CB terminals shown in Fig. 34 (b), the output offset between the CBs is 743 [mV], the output change between the CBs is 2.6 [mV], and the output change rate between the CBs is 0.35 [%]. ], The resistance change rate is 0.0026 / 0.7430 * 100 = 0.35 [%]. Regarding the output characteristics of the operational amplifier shown in Fig. 35 (c), the output offset between ACs is 1.46 [mV], the output change between ACs is 0.11 [mV], and the output change rate between ACs is 7.5 [%. ], Resistance change rate 0.00011 / 0.00146 * 100 = 7.5 [%]).

0135In FIGS. 34 (a) and 34 (b), the resistance changes significantly with respect to the magnetic field. It can be seen in FIG. 35 (c) that the bias voltage is significantly reduced as compared with FIGS. 34 (a) and 34 (b). Moreover, the change in output voltage due to the magnetic field is small. Therefore, it is considered that the direction of magnetization and the magnetic domain structure in the magnetic film 1c are in a multimagnetic domain state and do not become a single magnetic domain having uniaxial anisotropy.

0136<tables num="1"><img id="000002" he="70" wi="148" file="JP5773547B2_D0001.tif" img-format="tif" img-content="drawing" /></tables>

0137Table 1 shows the output improvement results by the barber pole magnetic film. It is presumed that the reason why the rate of change of output (output voltage) is greatly reduced is that the magnetization in the film is not sufficiently aligned in the longitudinal direction of the device. However, it can be seen that the resistance change rate is sharply improved by the sharp decrease of the offset voltage, and the performance as a device is remarkably improved by the differential connection of the barber pole magnetic film 1. The reduction of the offset voltage brings about the merit that the amplification factor of the amplifier circuit connected to the element can be increased, which seems to be a very useful result.

0138Further, FIG. 36 shows a schematic diagram of the measurement system when a bias magnetic field is applied in parallel with the long axis. As described above, the change in the characteristics of the element (device) was investigated by forcibly aligning the magnetization directions in one direction.

0139The output characteristics of the measurement system of FIG. 36 are shown in FIG. 37. FIG. 37 (a) shows the output characteristics when a bias magnetic field is applied in the longitudinal direction of the magnetic film in an element (differential connection) manufactured without a barber pole. The vertical axis is the output voltage (V), and the horizontal axis is the magnetic field (Oe) from the outside. As is clear from this, the resistance change is very small when there is no barber pole and there is a bias magnetic field. The rate of change in resistance was 0.00022%, which was very small.

0140FIG. 37 (b) shows the output characteristics of an element with a barber pole and no bias magnetic field in the longitudinal direction of the magnetic film, that is, the output characteristics when no DC bias magnetic field is applied in the longitudinal direction of the barber pole magnetic film 1. ing. The vertical axis is the output voltage (V), and the horizontal axis is the magnetic field (Oe) from the outside.

0141FIG. 37 (c) shows the output characteristics of an element with a barber pole and a bias magnetic field in the longitudinal direction of the magnetic film, that is, the output characteristics when a DC bias magnetic field is applied in the longitudinal direction of the barber pole magnetic film 1. .. The vertical axis is the output voltage (V), and the horizontal axis is the magnetic field (Oe) from the outside. It can be seen that the output characteristics change significantly depending on whether or not a bias magnetic field is applied in the longitudinal direction of the device. It can be inferred that this is because the anisotropy of the magnetic film is not strong enough.

0142It is presumed that this is because the magnetization was strongly aligned in the magnetic field direction due to the bias magnetic field in the longitudinal direction of the element that compensated for the strength of the anisotropy, and a clear angle was created between the magnetization and the current. The resistance change rate is 0.6% when there is no bias magnetic field and 3.3% or more when there is a bias magnetic field, and it can be said that the bias magnetic field is very effective.

0143FIG. 38 shows a measurement system of characteristics as a wattmeter when a load current (I1) is passed through the conductor film. In the original power measurement, the load current (I1) flowing through the load is measured by passing the load current (I1) flowing through the load through the conductor film, and the current (I2) proportional to the magnitude of the load voltage is passed through the magnetic film. However, in Fig. 38, the characteristics were evaluated by allowing I1 and I2 to be set individually.

0144FIG. 39 shows the output characteristics when a load current (I1) is passed through the conductor film without applying a bias magnetic field. The left vertical axis is the output (V), the right vertical axis is the current (A) passed through the conductor film, and the horizontal axis is the time (sec). In this measurement, the direct current (I2) flowing through the magnetic film was set to 2 mA. The load current (I1) was set using a DC power supply connected to the load resistor. The load current was increased from 0 [A] to 1 [A] in 0.2 [A] increments, and then decreased in 0.2 [A] increments for 50 [s].

0145It can be seen that the output increases as the load current (I1) increases. However, it cannot be said that the change in the power sensor output clearly reflects the change in the current with respect to the change in the load current. It seems that one of the reasons is that the direction of magnetization of the magnetic film does not move in proportion to the applied magnetic field.

0146FIG. 40 shows the output change due to the application of a magnetic field in the longitudinal direction of the device (longitudinal direction of the magnetic film). The vertical axis is the power sensor output (V), and the horizontal axis is the external magnetic field (Oe). In the graph, the circles are for the major axis bias magnetic field of zero, the squares are for 10Oe, the triangles are for 40Oe, and the black squares are for 100Oe. In the non-magnetic field state (circle), the output as a wattmeter is not uniquely determined in this state due to the relationship between the anisotropy strength of the magnetic film and the direction of magnetization, and cannot be expected as a wattmeter.

0147However, when the magnitude of the applied magnetic field is 100e or 400e, linearity and good sensitivity can be obtained in a wide range. In addition, although the sensitivity is clearly reduced when 1000e is applied, it can be seen that the linear region is wider than when 100e and 400e are applied. When the bias magnetic field has a certain size, the magnetic domain structure of the film can be adjusted, and high sensitivity and good linearity can be obtained, but it is clear that a large bias magnetic field lowers the sensitivity.

0148Applying a bias magnetic field that slightly exceeds the holding force of the magnetic film has the effect of greatly improving the sensitivity of the wattmeter. Further, it can be said that an applied magnetic field equal to or higher than the anisotropic magnetic field has the effect of reducing the sensitivity but expanding the operating range as a wattmeter. It can be said that the measurable current (electric power) can be set by changing the magnitude of the applied magnetic field. However, the sensitivity is reduced.

0149FIG. 41 shows a measurement system when a bias magnetic field is applied. Here, a bias magnetic field was applied using a permanent magnet. The magnitude of the magnetic field was set by adjusting the distance of the magnets.

0150Further, FIG. 42 shows the output characteristics of this magnetoresistive type magnetic film power sensor when a bias magnetic field is applied. The left vertical axis is the sensor output (V), the right vertical axis is the current value (A) passed through the conductor film, and the horizontal axis is the time (sec). The magnitude of the bias magnetic field is 400e. Other measurement conditions are the same as in FIG. 39. From this FIG. 42, it is clear that the applicability of the bias magnetic field improves the followability of the output voltage to the current change. In addition, although an error of Wakasen has occurred, it is thought that it can be greatly improved by improving the film characteristics and applying an AC bias. Moreover, it seems that it works without any problem in AC power measurement.

0151From the above results, it can be concluded that the barber pole type magnetic film magnetic film power sensor and the differential type barber pole magnetic film magnetic film power sensor are most suitable for application to smart grids, smart batteries, etc., and to avoid power shortages, etc. Is also advantageous.

0152Although the embodiments and concepts of various magnetic film power sensors of the present invention have been described above, the present invention is not limited thereto and deviates from the spirit and teachings described in the claims and the specification. Those skilled in the art will understand that other modifications and improvements can be obtained to the extent that they are not used.

0153Next, the sensor was used when measuring the battery power, the DC power was measured, and the linearity and accuracy of the sensor output were examined. Figure 43 shows the reluctance response curve of the sensor used for DC power measurement. The vertical axis is the differential resistance value (Ω), and the horizontal axis is the applied magnetic field (Oe). An external magnetic field of 0.02 Hz is applied from the outside for measurement.

0154The operating range of the power sensor is the part where the magnetic field near the magnetic field H = 0 and the resistance value are in a proportional relationship. Sensor A (Fig. 43) and Sensor B (Fig. 44) use two batteries for battery charge / discharge power measurement, which will be described later, and measure the power of each battery using two sensors. .. The two sensors are called sensor A and sensor B, respectively.

0155Next, FIG. 44 shows the magnetoresistive effect characteristics of the sensor B. Sensor A and sensor B are each formed by vacuum-depositing permalloy on a glass substrate and etching to form a pattern. The pattern of the elements used is shown in FIG. 45 (a). The structure is such that the magnetic film tilted diagonally is arranged symmetrically.

0156The reluctance response curves shown in FIGS. 43 and 44 show the difference in resistance value (differential resistance) between AB and BC in FIG. 45. A bias magnetic field of 10 Oe is applied to both sensor A and sensor B when measuring the magnetoresistance response curve. The direction of the bias magnetic field is the direction of Hbias in FIG. 45. An enlarged view of the pattern of FIG. 45 (a) is shown in FIG. 45 (b). The magnetization direction of the magnetic film is applied by the bias magnetic field Hbias from A and B to C.

0157The sensor of FIG. 45 will be described. The element in FIG. 45 (a) is a magnetic film formed in the shape of an arrow feather. From terminal A to terminal C, inclined portions that descend to the right toward the paper surface are connected in series, and from terminal C to terminal B, inclined portions that rise to the right toward the paper surface are connected in series.

0158In this sensor, if the resistance value between the terminals AB is the resistance value AB and the resistance value between the terminals CB is the resistance value CB, the differential resistance is obtained by (resistance value AB)-(resistance value CB). That is, this sensor can reduce the DC bias. In addition, this sensor is used by applying a DC bias magnetic field (see FIG. 45 (a)) in the Hbais direction.

0159With reference to FIG. 45 (b), on the left side of the arrow feather shape, inclined magnetic film pieces are connected in series. Here, when a bias magnetic field is applied in the direction of the arrow, the magnetization in the magnetic film is aligned in the bias direction. On the other hand, when a current is passed from the terminal A to the terminal C, a current inclined by an angle θ to the left with respect to the magnetization direction flows in the inclined portion.

0160On the other hand, on the right side of the arrow feather shape, the inclination of the magnetic film piece is opposite to that on the left side, so the current for magnetization flows to the right side by an angle θ. This is because the current flows from the terminal C toward the terminal B.

0161In this state, the conductor film 60 is put on the sensor as shown by the dotted line, and a current is passed from the terminal V1 to the terminal V2. Then, a magnetic field H is generated from the right to the left of the paper. With reference to FIG. 45 (b), this magnetic field tilts the magnetization of the magnetic film. At this time, on the left side of the arrow feather shape, the magnetization moves so as to approach the current, and on the right side of the arrow feather shape, the magnetization tilts in the direction away from the current.

0162If the right side and the left side of the arrow feather shape are made in the same way, the reluctance characteristics between AC and CB can be made almost the same. Moreover, since the inclination directions of the magnetic film pieces are different on the left and right, the polarities between AC and CB are opposite. Therefore, if the difference between the resistance between AC and the resistance between CB is taken, even if there is a DC bias, it can be canceled.

0163Here, the bias magnetic field will be described. The magnetic film is made up of a large number of magnetic domains, and the magnetization direction is slightly deviated from each magnetic domain. The magnetic film power sensor is used in a single magnetic domain by applying a magnetic field from the outside in order to align the magnetization directions. The external magnetic field is called a bias magnetic field.

0164DC power measurement was performed using the magnetoresistive response sensors shown in FIGS. 43 and 44. The experimental system is shown in FIG. The sensor voltage is kept constant at 20V with a DC power supply, and the load current is changed step by 1A between 1A and 4A. Rmr1 and Rmr2 are the sensor parts, R1 and R2 are fixed resistors, and R is a variable resistor to balance the bridge, and the differential outputs of V1 and V2 in Fig. 46 are measured as sensor outputs.

0165The average sensor output values in Tables 2 and 3 represent the average value of the sensor output at each power consumption, and the sensor output conversion value linearly approximates the power consumption and the average sensor output value, and consumes each sensor output from that straight line. It is converted into electric power. The error between the converted value and the theoretical value is shown on the right side of the table. The maximum error is 1.3%, and the power can be measured accurately. In the graph of FIG. 47 (b), the horizontal axis is the power consumption (W) and the vertical axis is the sensor output (V), and it can be seen that the output is linear.

0166<tables num="2"><img id="000003" he="42" wi="154" file="JP5773547B2_D0001.tif" img-format="tif" img-content="drawing" /></tables>

0167<tables num="3"><img id="000004" he="37" wi="154" file="JP5773547B2_D0001.tif" img-format="tif" img-content="drawing" /></tables>

0168Next, the result of DC power measurement of sensor B is shown in FIG. Sensor B is also output with good linearity. The cause of the error is the influence of the offset voltage due to the bridge circuit not being perfectly balanced during measurement, and the magnetoresistive response curve is completely in the operating range of the sensor. It is possible that it is not linear.

0169Next, two in-vehicle batteries are connected in series, charged and discharged, and the power is measured using a magnetic film power sensor.

0170In recent years, due to environmental problems, CO of greenhouse gases while driving₂Quiet and comfortable electric vehicles (hereinafter referred to as EVs) are becoming widespread because they do not emit electricity and use a motor instead of an engine to reduce vibration. This electric vehicle is equipped with a large number of lithium-ion batteries connected in series in parallel in several rows.

0171When a lithium-ion battery is overcharged, it will ignite or explode in the worst case. Also, with batteries other than lithium-ion batteries, overcharging or overdischarging may accelerate the deterioration of the batteries. Taking advantage of the small size and light weight of the magnetic film power sensor, these problems can be solved by incorporating the sensor into each battery and monitoring the remaining power amount. Figure 49 shows the circuit during charging and discharging.

0172Batteries A and B use similar products, battery A is new, and battery B has significantly reduced battery capacity due to aging. By using such a battery, an imbalance of electric power occurs between the batteries both during charging and discharging. We are using two batteries, a new battery and a deteriorated battery, with the aim of accurately measuring power, including such imbalances in each battery.

0173This time, 2A constant current discharge is performed for discharging, 1.5A constant current charging is performed for charging, and the power of battery A is measured by sensor A and the power of battery B is measured by sensor B. At the time of this measurement, since the sensor output A is larger at the same power consumption in the DC power measurement performed earlier, by adjusting the vertical bias magnetic field applied to each sensor, the same power consumption is almost the same. It is adjusted so that the sensor output is output. FIG. 50 shows the result at the time of discharging, and FIG. 51 shows the result at the time of charging.

0174FIG. 50 (a) shows the relationship between power consumption and time when battery A is discharged, FIG. 50 (b) is when battery B is discharged, and FIG. 50 (c) is when batteries A and B are connected in series. In each graph, the left vertical axis is power consumption (W), the right vertical axis is sensor output (V), and the horizontal axis is time (min).

0175Although not shown, a voltmeter is placed at the electrode terminals of battery A and battery B so that the current flowing through the entire measurement circuit can be measured, and the charging power and power consumption (discharge power) of battery A and battery B are measured. ) Can be measured individually.

0176With reference to Figure 50, Battery A was a new battery and was able to discharge a constant amount of power during the measurement. When the power consumption and the sensor output are overlapped, the same behavior is indistinguishable. Since battery B is a deteriorated battery, power loss occurred in the latter half of the measurement. In this case as well, it can be seen that the power consumption and the sensor output behave exactly the same.

0177When batteries A and B were connected in series and viewed as a whole, the characteristics of batteries A and B were added as they were, and the overall characteristics also decreased at the part where the discharge power of battery B decreased. FIG. 51 is a graph similar to FIG. 50, except that it is specific during charging.

0178When discharging, it discharges for 70 minutes, and when charging, it charges for 110 minutes. It can be seen that the power can be measured accurately both during charging and discharging. By mounting a sensor on each battery and monitoring its output as in this measurement, it is possible to detect which battery has an abnormality when an abnormality occurs in the battery, and a security sensor. It was shown to play a role as.

0179As described above, the charge / discharge power of the in-vehicle battery was measured using the magnetoresistive thin film wattmeter. Before doing this, first measure the magnetoresistive effect characteristics of the sensor to be used, measure the DC power using that sensor, confirm that it is functioning as a power sensor, and confirm the linearity and accuracy of the sensor output. Was done. The charge / discharge power of the battery was measured using two batteries, a new battery and a battery that had deteriorated over time. It was confirmed that the sensor output was able to measure the charge / discharge power with high accuracy.

0180Further, in the above, only the charge / discharge power measurement of the battery is dealt with, but the thin film power sensor can measure both AC power (including high frequency) and Nth harmonic. Such a multifunctional power sensing device has not existed in the past. In addition, since the sensor can be manufactured with a size of about 5 mm x 5 mm, it can be incorporated into all home appliances.

0181In the circuit of FIG. 46, the power consumption of direct current was measured (FIGS. 47 and 48), but it was confirmed that the same can be measured for alternating current. FIG. 52 shows the measurement results when the frequency is 60 Hz, the voltage is 20 V, and the current is 1 to 4 A. Table 4 shows the measured values at that time.

0182<tables num="4"><img id="000005" he="50" wi="155" file="JP5773547B2_D0001.tif" img-format="tif" img-content="drawing" /></tables>

0183In addition, a smaller sensor (3 mm x 3 mm) in FIG. 45 was manufactured, and similar characteristics could be obtained. The reluctance response curve of the sensor is shown in FIG. 53, and the power measurement result is shown in FIG. 54. It can be seen that the linearity can be measured as well as in the case of direct current.

0184The battery system of the present invention can be widely used as a power source for a robot that is driven by electricity such as an automobile, an airplane, or a ship, or an autonomously driven robot regardless of whether it is for industrial use or consumer use. Further, the charge / discharge measuring device according to the present invention can be used not only for a system using a battery but also for measuring power consumption at a place where electricity is used, regardless of whether it is for industrial use or consumer use.

01851 Magnetic film power sensor 1a Conductor membrane 1b Insulation film 1c magnetic film 3 Rectifier circuit (pridge circuit) 4 charger 5 Changeover switch 26 Sensor resistance 27 Sensor voltmeter 28 Conductor membrane 29 Magnetic film 30 Battery system 30t1, 30t2 external terminal 32 rechargeable battery 34 Magnetic film power sensor 36 Battery voltmeter 40 Inspection resistance 42 Inspection switch 44 Connection switch 46 Control unit 46t timer 48 Display 50 charger 52 load R1 load R2 resistor R3 dummy resistor Rcu primary conductor Rmr magnetic film