JP2005033855A - Battery assembly - Google Patents

Abstract

Variations in cell voltage in an assembled battery are corrected.
A switching element is connected in series to a primary coil that is magnetically coupled to a secondary coil of an adjacent cell for each cell of a battery pack in which a plurality of unit secondary battery cells are connected in series. A power input in which a rectifier 22 is connected in series to the power output circuit 10 and the secondary coil 21 magnetically coupled to the primary coil 31 of the adjacent cell C2, and current flowing from the cell C1 to the secondary coil 21 is blocked by the rectifier 22. A switching element that is connected to the circuit 20 in parallel, has the same ON time as the switching element 32 of the adjacent cell C2, and that turns on and off the switching element 12 so as not to be turned on simultaneously with the switching element 32 of the adjacent cell C2. And a turn ratio of the secondary coils 21 and 41 with respect to the primary coils 11 and 31 is made larger than 1.
[Selection] Figure 1

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an assembled battery device in which a plurality of unit batteries are connected in series and parallel.
[0002]
[Prior art]
In a power battery used for an electric vehicle, a high voltage is realized by connecting a plurality of unit secondary battery cells in series. When charging such an assembled battery, the charging voltage varies due to variations in internal impedance and capacity of each cell. However, since a plurality of cells are connected in series, the same charging current flows through each cell, and the variation in charging voltage causes an overcharged state of some cells.
[0003]
In an assembled battery in which a plurality of unit secondary battery cells are connected in series, an assembled battery device is known in which variation in charging voltage is suppressed (see, for example, Patent Document 1). In this assembled battery device, a series circuit of a primary coil and a switching element is connected in parallel to each cell. The primary coil is electromagnetically coupled to the secondary coil, the primary coil of another cell, and the secondary coil of another cell via the core. Each cell is connected to a voltage control circuit. The cell voltage is monitored by this voltage control circuit, and when the voltage becomes larger than a predetermined value, electric power is transmitted to an adjacent cell having a voltage lower than the predetermined value by electromagnetic coupling, and the variation in charging voltage is improved.
[0004]
Prior art documents related to the invention of this application include the following.
[Patent Document 1]
Japanese Patent Laid-Open No. 10-257682
[Problems to be solved by the invention]
However, in the above-described conventional assembled battery device, power is transmitted only from a cell having a voltage higher than a predetermined value to a cell having a voltage lower than the predetermined value, so that the voltages of two adjacent cells are both When the value is higher than the predetermined value or lower than the predetermined value, power is not transmitted, and the variation in charging voltage cannot be sufficiently improved.
[0006]
Further, in a cell whose voltage is higher than a predetermined value, even when power cannot be transmitted, a switching operation is performed by the switching element, so that a switching loss occurs and the charging efficiency is lowered.
[0007]
The present invention provides an assembled battery device that corrects variations in cell voltage in an assembled battery.
[0008]
[Means for Solving the Problems]
In the present invention, a switching element is connected in series to a primary coil that is magnetically coupled to a secondary coil of an adjacent cell for each cell of an assembled battery in which a plurality of unit secondary battery cells (hereinafter simply referred to as cells) are connected in series. A rectifier is connected in series to the connected power output circuit and a secondary coil that is magnetically coupled to the primary coil of the adjacent cell, and a power input circuit that blocks current flowing from the cell to the secondary coil by the rectifier is connected in parallel. And a switching element driving circuit for turning on and off the switching element so as not to be turned on simultaneously with the switching element of the adjacent cell. Make the turns ratio greater than 1.
[0009]
【The invention's effect】
According to the present invention, it is possible to sufficiently correct variations in voltage among cells and equalize cell voltages.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
<< First Embodiment of the Invention >>
FIG. 1 is a circuit diagram of two adjacent cell portions of the battery pack apparatus according to the first embodiment. The assembled battery device of one embodiment is an assembled battery device in which a plurality of unit secondary battery cells (hereinafter simply referred to as cells) are connected in series, but the circuit for each cell is the same as that of the cell shown in FIG. Only the circuit of two adjacent cells is illustrated and described in the same manner as the circuit. In this assembled battery device, each cell is connected in parallel with a power output circuit for outputting power to an adjacent cell and a power input circuit for inputting power from the adjacent cell.
[0011]
In FIG. 1, a power output circuit 10 in which a primary coil 11 and a switching element 12 are connected in series and a power input circuit 20 in which a secondary coil 21 and a diode 22 are connected in series are connected in parallel to the cell C1. To do. Similarly, a power output circuit 30 in which a primary coil 31 and a switching element 32 are connected in series and a power input circuit 40 in which a secondary coil 41 and a diode 42 are connected in series are connected in parallel to the cell C2.
[0012]
The primary coil 11 of the power output circuit 10 of the cell C1 faces the secondary coil 41 of the power input circuit 40 of the cell C2 via the core 13, and the primary coil 11 and the secondary coil 41 are magnetically coupled. Function as a transformer. The secondary coil 21 of the power input circuit 20 of the cell C1 faces the primary coil 31 of the power output circuit 30 of the cell C2 through the core 33, and the primary coil 31 and the secondary coil 21 are magnetically connected. Combine and function as a transformer. Here, the number of turns of the primary coils 11 and 31 and the number of turns of the secondary coils 21 and 41 are the same in any cell, and the turn ratio n of the primary coils 11 and 31 and the secondary coils 21 and 41 is set to a value larger than 1.
[0013]
FIG. 2 is a time chart showing the operation of the switching element, where (a) shows the on / off timing of the switching element 12 of the cell C1, and (b) shows the on / off timing of the switching element 32 of the cell C2. Show. As is apparent from the figure, the switching element 12 of the cell C1 and the switching element 32 of the cell C2 are alternately turned on and off alternately, and are not turned on at the same time. Note that the ON times of the switching elements 12 and 32 of the cells C1 and C2 are the same.
[0014]
Next, the operation of the first embodiment will be described. Here, it is assumed that the assembled battery device is charged to some extent by a charging circuit (not shown), and the voltages of the cells C1 and C2 (hereinafter referred to as cell voltages) reach VA and VB, respectively. The switching element 12 of the cell C1 self-oscillates at the timing shown in FIG. 2A, and when the switching element 12 is turned on, a current flows from the cell C1 to the primary coil 11 via the switching element 12. When a current flows through the primary coil 11, a voltage of (n · VA) is induced in the opposing secondary coil 41. When the induced voltage (n · VA) is larger than the voltage VB of the cell C2, a current flows from the secondary coil 41 to the cell C2 via the diode 42, and the cell C2 is charged.
[0015]
When the induced voltage (n · VA) is lower than the voltage VB of the cell C2, the discharge current tends to flow from the cell C2 to the secondary coil 41. However, since the discharge current is blocked by the diode 42, the cell C2 is not discharged. That is, the diodes 22 and 42 of the power input circuits 20 and 40 of the cells C1 and C2 prevent the discharge of the cells C1 and C2 in the power input circuits 20 and 40, respectively.
[0016]
Next, the switching element 12 of the cell C1 is turned off, the switching element 32 of the cell C2 is self-excited at the timing shown in FIG. 2B, and when the switching element 32 is turned on, the primary is transmitted from the cell C2 via the switching element 32. A current flows through the coil 31. When a current flows through the primary coil 31, a voltage of (n · VB) is induced in the opposing secondary coil 21. When the induced voltage (n · VB) is larger than the voltage VA of the cell C1, a current flows from the secondary coil 21 to the cell C1 via the diode 22, and the cell C1 is charged.
[0017]
When the induced voltage (n · VB) is lower than the voltage VA of the cell C1, the discharge current tends to flow from the cell C1 to the secondary coil 21, but the discharge current is blocked by the diode 22, so that the cell C1 does not discharge.
[0018]
The switching elements 12 and 32 of the cells C1 and C2 have the same on time and are alternately turned on, so that power is alternately transferred between the cells C1 and C2. If the voltage VA of the cell C1 is larger than the voltage VB of the cell C2, the power transmitted from the cell C1 to the cell C2 is larger than the power transmitted from the cell C2 to the cell C1, and on average, the cell C1 to the cell C1. Power is transmitted to C2. As a result, the voltage VA of the cell C1 decreases, the voltage VB of the cell C2 increases, and the voltages of the cells C1 and C2 are equalized. Conversely, when the voltage VB of the cell C2 is higher than the voltage VA of the cell C1, power is transmitted from the cell C2 to the cell C1, and the voltages of the cells C1 and C2 are equalized.
[0019]
Note that the primary coil 11 and the secondary coil 21 of the cell C1 are electromagnetically coupled to the secondary coil 41 and the primary coil 31 of the cell C2 via separate and independent cores 13 and 33, respectively. Electric power does not circulate from the coil 11 to the secondary coil 21 or from the primary coil 31 to the secondary coil 41 of the cell C2.
[0020]
In addition, in the conventional assembled battery device described above, there is a problem in that power is not exchanged when the voltages of adjacent cells exceed a predetermined value, and the cell voltages are not sufficiently equalized. According to the embodiment, power is exchanged between adjacent cells regardless of the cell voltage, so that the voltage is reliably equalized between adjacent cells. Since the cell voltage, that is, the state of charge of the cells is surely equalized between adjacent cells, voltage variations between the cells are eliminated, and the life of the assembled battery as a whole can be extended.
[0021]
Furthermore, in this embodiment, the turn ratio n is set to a value larger than 1, and the voltage is boosted during power transfer, so that the influence of the forward voltage drop VF of the diodes 22 and 42 can be ignored. That is, when the voltage difference between the cells C1 and C2 becomes VF / n or less, power cannot be transferred due to the voltage drop VF of the diodes 22 and 42, and further equalization cannot be performed. As the winding ratio n is increased, VF / n can be reduced and equalization can be performed with high accuracy.
[0022]
Thus, for each cell of a battery pack in which a plurality of unit secondary battery cells are connected in series, a power output circuit in which a switching element is connected in series to a primary coil that is magnetically coupled to a secondary coil of an adjacent cell, and adjacent A diode is connected in series to a secondary coil that is magnetically coupled to the primary coil of the cell, and a power input circuit that blocks current flowing from the cell to the secondary coil by the diode is connected in parallel, and the switching element of the adjacent cell Since the switching element is turned on and off so that it does not turn on simultaneously with the switching element of the adjacent cell, and the turn ratio of the secondary coil to the primary coil is greater than 1, the same on-time is ensured between adjacent cells. Thus, it is possible to equalize cell voltages by sufficiently exchanging power and sufficiently correcting variations in voltage among cells. Therefore, the life of the entire assembled battery can be extended.
[0023]
In addition, since the diode that blocks the discharge current flowing from the cell to the secondary coil of the power input circuit is connected in series with the secondary coil, the switching element of the cell power output circuit is the same as the switching element of the adjacent cell. In addition to the on-time, it is only necessary to turn on and off so that it does not turn on simultaneously with the switching element of the adjacent cell, and it is not necessary to strictly control the on / off timing of the switching element. Locking is unnecessary, the control wiring can be simplified, and the mounting density can be increased.
[0024]
<< Second Embodiment of the Invention >>
As described above, in the assembled battery device according to the first embodiment shown in FIG. 1, for example, when the switching element 12 is turned on, a current flows through the primary coil 11, thereby inducing an electromotive force in the secondary coil 41. It operates in the same way as a so-called forward switching regulator. In this method, when power is transmitted from the primary coil 11 to the secondary coil 41, it is not always necessary to store energy in the core 13, and the core 13 can be made unnecessary. Note that a flyback switching regulator requires a relatively large core because energy needs to be stored in the core.
[0025]
FIG. 3 shows a circuit diagram of two adjacent cell portions of the assembled battery device according to the second embodiment. In this assembled battery device, the core 13 between the primary coil 11 and the secondary coil 41 and the core 33 between the primary coil 31 and the secondary coil 21 are deleted from the assembled battery device shown in FIG. The circuit configuration other than the deletion of the cores 13 and 33 is the same as the circuit configuration shown in FIG.
[0026]
FIG. 4 shows an example of mounting the assembled battery device of the second embodiment shown in FIG. In this mounting example, one cell and a control circuit such as a power output circuit and a power input circuit of the cell are housed in one package. The cell C1 shown in FIG. 3 and the control circuit such as the power output circuit 10 and the power input circuit 20 of the cell C1 are housed in one package to form the cell unit 50, and the power output of the cell C2 and the cell C2 Control units such as the circuit 30 and the power input circuit 40 are housed in one package to form the cell unit 60. Electrodes 51, 52 and 61, 62 are provided on the upper surfaces of the cell units 50, 60, respectively.
[0027]
The primary coil 11 of the power output circuit 10 and the secondary coil 21 of the power input circuit 20 are formed on the surface of the cell unit 50 that houses the cell C1 that faces the cell unit 60. Further, the primary coil 31 of the power output circuit 30 and the secondary coil 41 of the power input circuit 40 are formed on the surface of the cell unit 60 that houses the cell C2 that faces the cell unit 50. Here, as shown in FIG. 3, the primary coil 11 of the power output circuit 10 of the cell C1 and the secondary coil 41 of the power input circuit 40 of the cell C2 face each other, and the primary coil of the power output circuit 30 of the cell C2 The primary coils 11 and 31 and the secondary coils 21 and 41 are arranged so that 31 and the secondary coil 21 of the power input circuit 20 of the cell C1 face each other.
[0028]
If the coil installation surfaces of the cell unit 50 of the cell C1 and the cell unit 60 of the cell C2 are arranged to face each other, the opposing primary coil 11 and secondary coil 41, and the primary coil 31 and secondary coil 21 are magnetically coupled. Even without a core, power can be transmitted from the primary coil 11 to the secondary coil 41 and from the primary coil 31 to the secondary coil 21.
[0029]
The shape of the storage package of the cell and its peripheral circuit is preferably a flat type as shown in FIG. An assembled battery device by mounting a primary coil and a secondary coil on the front and back surfaces of a flat package, respectively, and arranging cell units in a row at intervals necessary for insulation between adjacent cells and cooling of the cells. Can be miniaturized.
[0030]
In this way, one cell and the power output circuit, power input circuit and switching element driving circuit of the cell are housed in one flat package, and a primary coil and a secondary are respectively provided on the front and back surfaces of the flat package. Since the coil is mounted, the mounting density of the assembled battery device can be increased, and the assembled battery device can be reduced in size. Further, since the core can be eliminated, the assembled battery device can be mounted with high density, and the assembled battery device can be further reduced in size.
[0031]
When the cell and the power output circuit and power input circuit of the cell are mounted as shown in FIG. 4, the following effects are also obtained. That is, in the assembled battery device according to the embodiment, the electric power induced in the secondary coils 21 and 41 is rectified using the diodes 22 and 42 in the power input circuits 20 and 40. Therefore, the switching element 12 of the power output circuit 10 of the cell C1 only needs to be controlled so as to be turned on for the same time as the switching element 32 of the power output circuit 30 of the adjacent cell C2 and not simultaneously turned on. , 32 is not strictly required for on / off control timing. Therefore, it is not necessary to exchange many control signals for on / off control of the switching elements 12 and 32, and the control signals between the cell units 50 and 60 can be made unnecessary. The control circuit for each cell can be completely separated. As described above, since all the wirings including the control circuit can be localized for each cell unit, and long signal wirings extending over the entire assembled battery can be made unnecessary, the circuit mounting density can be increased.
[0032]
<< Third Embodiment of the Invention >>
FIG. 5 shows an example of a control circuit mounted in the cell unit. FIG. 5 shows only the control circuit 70 of the cell C1, but the control circuits of other cells are the same. In the power output circuit 10 of the cell C1, a self-excited oscillation circuit 14 and an AND element 15 for controlling on / off of the switching element 12 are used. The power input circuit 20 of the cell C1 is connected to a current detection resistor 23 in series with the secondary coil 21 and the diode 22 and an inverter 24 that inverts and amplifies the current detection signal.
[0033]
When the switching element 32 of the power output circuit 30 of the adjacent cell C2 is turned on and a current flows through the primary coil 31, a current flows through the secondary coil 21 of the power input circuit 20 of the cell C1, and the current flows from the cell C2 to the cell C1. Electric power is transmitted. At this time, a voltage is generated at both ends of the current detection resistor 23, and the inverter 24 inverts and amplifies this voltage and outputs a low level signal to the AND element 15. Thereby, when power is transmitted from the adjacent cell C2 in the power input circuit 20, even if the on signal is output from the self-excited oscillation circuit 14, the on signal to the switching element 12 is blocked by the AND element 15. Is done. That is, when power is received from the neighboring cell C2, transmission of power to the neighboring cell C2 is prohibited.
[0034]
As described above, the control circuit 70 detects the current by the self-excited oscillation circuit 14 that turns the switching element 12 on and off, the current detection circuit 23 that detects the current flowing through the power input circuit 20, and the current detection circuit 23. In some cases, since the on-inhibiting circuit 15 for inhibiting the switching element 12 from being on is provided, the control signal lines between the cell units can be made unnecessary, and the wiring of all the circuits in the cell unit can be localized. The mounting density can be increased.
[0035]
<< Fourth Embodiment of the Invention >>
In the control circuit 70 of the third embodiment described above, an example is shown in which the current detection resistor 23 is connected in series with the secondary coil 21 and the diode 22 of the power input circuit 20 to detect that power is being received. . In the control circuit 70A of the fourth embodiment, as shown in FIG. 6, a tertiary coil 25 electromagnetically coupled to the secondary coil 21 of the power input circuit 20 is provided, and a diode 26 is connected in series with the tertiary coil 25. In addition, a current detection circuit 29 connected to the current detection resistor 27 is provided. FIG. 6 shows only the control circuit 70A of the cell C1, but the control circuits of other cells are the same.
[0036]
When power is received from the adjacent cell C2, a current flows through the secondary coil 21 of the power input circuit 20. At the same time, an electromotive force is generated in the tertiary coil 25 by the electromagnetic induction action, and a current flows in the current detection circuit 29. As a result, a voltage is generated at both ends of the current detection resistor 25, and the inverter 28 inverts and amplifies this voltage and outputs a low level signal to the AND element 15. Thereby, when power is transmitted from the adjacent cell C2 in the power input circuit 20, even if the on signal is output from the self-excited oscillation circuit 14, the on signal to the switching element 12 is blocked by the AND element 15. Is done. That is, when power is received from the neighboring cell C2, transmission of power to the neighboring cell C2 is prohibited.
[0037]
Note that by making the number of turns of the tertiary coil 25 smaller than the number of turns of the secondary coil 21, the current flowing through the current detection circuit 29 at the time of power reception can be reduced, and the power consumption of the current detection resistor 27 can be reduced. Loss can be reduced.
[0038]
In this way, the power detection circuit 29 has the tertiary coil 25 that is magnetically coupled to the secondary coil 21 and has more turns than the secondary coil 21, and the diode 26 and the power detection resistor 27 are connected in series with the tertiary coil 25. Therefore, the power consumption and loss due to the current detection resistor 27 can be suppressed, and the charging efficiency can be further increased.
[0039]
<< Fifth Embodiment of the Invention >>
FIG. 7 shows a control circuit of the fifth embodiment. FIG. 7 shows only the control circuit 70B of the cell C1, but the control circuits of other cells are the same. In the control circuit 70B of the fifth embodiment, a voltage detection circuit 71 that detects a voltage induced in the secondary coil 21 of the power input circuit 20 when power is received is provided. The voltage detection circuit 71 includes a diode 72, an amplifier 73 that outputs 1 / n of the induced voltage of the secondary coil 21, and a differential amplifier that compares the cell voltage VA of the cell C1 with the voltage of 1 / n of the induced voltage. 74.
[0040]
The voltage induced in the secondary coil 21 when power is received is input to the amplifier 73 via the diode 72, and a voltage 1 / n of the induced voltage is output from the amplifier 73. As described above, since the turns ratio of the primary coils 11 and 31 and the secondary coils 21 and 41 is n larger than 1, the voltage 1 / n of the induced voltage of the secondary coil 21 is the primary coil on the cell C2 side. It is equal to the input voltage of 31, that is, the cell voltage VB of the cell C2. The differential amplifier 74 compares the cell voltage VA of the cell C1 and the cell voltage VB of the cell C2, and sends a signal corresponding to the cell voltage difference (VA−VB) between the adjacent cells C1 and C2 to the self-excited oscillation circuit 13. Output.
[0041]
The self-excited oscillation circuit 13 changes the oscillation frequency according to the cell voltage difference (VA−VB) signal. That is, the larger the cell voltage difference (VA−VB), the higher the oscillation frequency, and the lower the cell voltage difference (VA−VB), the lower the oscillation frequency.
[0042]
FIG. 8 is a time chart showing operation waveforms of the switching elements 12 and 32 of the cells C1 and C2. FIG. 8A shows an operation waveform when the cell voltage difference (VA−VB) is large, and FIG. 8B shows a cell voltage difference. The operation waveform when (VA-VB) is small is shown. Thus, as the cell voltage difference (VA−VB) between the adjacent cells C1 and C2 is larger, the operating frequency of the switching elements 12 and 32 is increased, and as the cell voltage difference (VA−VB) is decreased, the switching elements 12, Since the operating frequency of 32 is lowered, the wasteful power transmission operation when the cell voltage difference (VA-VB) is reduced can be reduced, and the charging efficiency can be improved.
[0043]
In this way, the induced voltage of the secondary coil 21 of the power input circuit 20 and the self-excited oscillation circuit 14 that turns on and off the switching element 12 in the circuit that drives the switching element 12 are the turns ratio of the primary coil and the secondary coil. An amplifier 73 for estimating the cell voltage VB of the adjacent cell C2 divided by n, and a difference for detecting a voltage difference (VA−VB) between the cell voltage VA of the cell C1 and the estimated cell voltage VB of the adjacent cell C2. Since the self-oscillation circuit 14 has a dynamic amplifier 74, the drive frequency for turning on and off the switching element 12 is lowered as the cell voltage difference (VA-VB) from the adjacent cell C2 becomes smaller. In addition, useless power transmission operation can be eliminated and charging efficiency can be improved.
[0044]
The correspondence between the constituent elements of the claims and the constituent elements of the embodiment is as follows. That is, the control circuits 70, 70A and 70B are the switching element driving circuit, the series circuit of the primary coil 11 and the switching element 12, the series circuit of the primary coil 31 and the switching element 30 are the power output circuit, the secondary coil 21 and the diode 22. And the series circuit of the secondary coil 41 and the diode 42 are the power input circuit, the diodes 22 and 42 are the rectifier, the self-excited oscillation circuit 14 is the self-excited oscillation circuit, the resistor 23 or the tertiary coil 25 and the diode 26. The series circuit of the resistor 27 and the resistor 27 constitute a current detection circuit, the AND element 15 constitutes an on-prohibition circuit, the amplifier 73 constitutes a cell voltage estimation circuit, and the differential amplifier 74 constitutes a cell voltage difference detection circuit. In addition, as long as the characteristic function of this invention is not impaired, each component is not limited to the said structure.
[Brief description of the drawings]
FIG. 1 is a partial circuit diagram of an assembled battery device according to a first embodiment.
FIG. 2 is a time chart showing operation waveforms of the switching element according to the first embodiment.
FIG. 3 is a partial circuit diagram of an assembled battery device according to a second embodiment.
FIG. 4 is a diagram illustrating a cell unit mounting example according to the second embodiment;
FIG. 5 is a diagram illustrating a control circuit mounted on a cell unit according to a third embodiment.
FIG. 6 is a diagram illustrating a control circuit mounted on a cell unit according to a fourth embodiment.
FIG. 7 is a diagram illustrating a control circuit mounted on a cell unit according to a fifth embodiment.
FIG. 8 is a time chart showing operation waveforms of a switching element according to a fifth embodiment.
[Explanation of symbols]
C1, C2 Cell 10, 30 Power output circuit 11, 31 Primary coil 12, 32 Switching element 13, 33 Core 14 Self-excited oscillation circuit 15 AND element 20, 40 Power input circuit 21, 41 Secondary coil 22, 26, 42, 72 Diodes 23, 27 Current detection resistor 24 Inverter 25 Tertiary coil 29 Current detection circuit 50, 60 Cell units 51, 52, 61, 62 Electrodes 70, 70A, 70B Control circuit 71 Voltage detection circuit 73 Amplifier 74 Differential amplifier

Claims (5)

For each cell of the assembled battery in which a plurality of unit secondary battery cells (hereinafter simply referred to as cells) are connected in series,
A power output circuit in which a switching element is connected in series to a primary coil that is magnetically coupled to a secondary coil of an adjacent cell, and a rectifier is connected in series to a secondary coil that is magnetically coupled to the primary coil of the adjacent cell. In parallel with the power input circuit that blocked the current flowing from the secondary coil to the secondary coil,
A switching element driving circuit for turning on and off the switching element so that the switching element of the adjacent cell has the same ON time and does not turn on simultaneously with the switching element of the adjacent cell;
An assembled battery device, wherein a turn ratio of the secondary coil to the primary coil is set to be larger than 1. The assembled battery device according to claim 1,
One cell, the power output circuit of the cell, the power input circuit, and the switching element driving circuit are housed in one flat package, and the primary coil and the An assembled battery device comprising a secondary coil. The assembled battery device according to claim 1 or 2,
The switching element driving circuit includes:
A self-excited oscillation circuit for turning on and off the switching element;
A current detection circuit for detecting a current flowing in the power input circuit;
An assembled battery device comprising: an on-forbidden circuit for inhibiting the switching element from being turned on when a current is detected by the current detection circuit. The assembled battery device according to claim 3,
The current detection circuit has a tertiary coil that is magnetically coupled to the secondary coil and has a larger number of turns than the secondary coil, and detects a current flowing in a circuit in which a rectifier and a resistor are connected in series with the tertiary coil. An assembled battery device. The assembled battery device according to claim 1 or 2,
The switching element driving circuit includes:
A self-excited oscillation circuit for turning on and off the switching element;
A cell voltage estimation circuit that estimates the cell voltage of an adjacent cell by dividing the induced voltage of the secondary coil of the power input circuit by the turns ratio of the primary coil and the secondary coil;
A cell voltage difference detection circuit for detecting a voltage difference between a cell voltage of the cell and a cell voltage of an adjacent cell estimated by the cell voltage estimation circuit;
The self-excited oscillation circuit reduces the drive frequency for turning on and off the switching element as the cell voltage difference with an adjacent cell becomes smaller.

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