JP6081165B2 - Battery management device and power supply device - Google Patents

Description

  The present invention relates to a battery management device that manages the state of a battery, and a power supply device that includes the battery management device.

  In recent years, hybrid vehicles (HV), plug-in hybrid vehicles (PHV), and electric vehicles (EV) have become widespread. These cars are equipped with secondary batteries as key devices. Nickel metal hydride batteries and lithium ion batteries are mainly used as in-vehicle secondary batteries. In the future, the spread of lithium ion batteries with high energy density is expected to accelerate.

  Lithium-ion batteries require close strict voltage management than other types of batteries because the regular use area and the use prohibition area are close to each other. When using an assembled battery in which a plurality of lithium ion battery cells are connected in series, a voltage detection circuit for detecting the voltage of each battery cell is provided. The detected voltage of each battery cell is used for charge / discharge control, cell voltage equalization control, and the like.

JP 2006-25501 A JP 2010-127722 A

  The number of cells of the assembled battery varies and differs depending on the vehicle type and specifications. Although it is ideal for the chip manufacturer to individually prepare a voltage detection circuit for each assembled battery having a different number of cells, the manufacturing cost and management cost increase. Even if the number of terminals to which the voltage detection line for detecting the voltage of each cell is connected does not match the number of cells, if the number of terminals is larger than the number of cells, it is actually the case that the voltage detection circuit is reused. is there.

  In this case, unconnected terminals that are not connected to the battery cell are generated. Since such a floating state is not a preferable state, it is required to fix the potential of the unconnected terminal. On the other hand, generally, an unconnected terminal is connected to another terminal having a fixed potential by a jumper or connected to a wire harness connected to a battery cell. However, additional hardware is required, and it is difficult to change the number of corresponding cells after the completion of mounting.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a technique for flexibly fixing the potential of an unconnected terminal of a voltage detection circuit without adding hardware.

  In order to solve the above-described problems, a battery management device according to an aspect of the present invention includes a voltage detection circuit for detecting voltages of a plurality of battery cells connected in series, and nodes and voltages of the plurality of battery cells. A plurality of voltage detection lines for connecting the detection circuit, a plurality of discharge switches connected between two adjacent ones of the plurality of voltage detection lines, and a plurality for equalizing the charge amounts of the plurality of battery cells A discharge control circuit for controlling the discharge switch. In the discharge control circuit, when there is an unconnected voltage detection line at the battery cell node among the plurality of voltage detection lines, the unconnected voltage detection line and the adjacent voltage detection line with a fixed potential are electrically connected. The discharge switch between both voltage detection lines is turned on.

  According to the present invention, the potential of the unconnected terminal of the voltage detection circuit can be flexibly fixed without adding hardware.

It is a figure for demonstrating the power supply device which concerns on embodiment of this invention. It is a figure for demonstrating a power supply device when the number of battery cells mounted is one less than the number of management cells of a voltage detection circuit (the 1). It is a figure for demonstrating a power supply device when the number of battery cells mounted is one less than the number of management cells of a voltage detection circuit (the 2). It is a figure for demonstrating a power supply device when the number of battery cells mounted is one less than the number of management cells of a voltage detection circuit (the 3). It is a figure for demonstrating a power supply device when the number of battery cells mounted is one less than the number of management cells of a voltage detection circuit (the 4). It is a figure for demonstrating a power supply device when the number of the battery cells mounted is two less than the number of management cells of a voltage detection circuit (the 1). It is a figure for demonstrating a power supply device when the number of battery cells mounted is two less than the number of management cells of a voltage detection circuit (the 2). It is a figure for demonstrating the power supply device in case the number of battery cells mounted is three fewer than the number of management cells of a voltage detection circuit.

  FIG. 1 is a diagram for explaining a power supply apparatus 100 according to an embodiment of the present invention. In this specification, it is assumed that the power supply apparatus 100 is mounted on a vehicle as a power source such as a hybrid car or an electric vehicle. In this example, the load 40 that is supplied with power from the power supply apparatus 100 is a precharge capacitor and a traveling motor.

  The power supply device 100 includes the assembled battery 10 and the battery management device 30. The assembled battery 10 and the battery management device 30 are connected by a wire harness 20. The assembled battery 10 includes a plurality of battery cells connected in series. Hereinafter, in the present specification, an assembled battery 10 configured by connecting six battery cells S1 to S6 in series is assumed. Further, a lithium ion battery is assumed as the type of battery.

  The battery management device 30 includes a voltage detection circuit 32, a discharge control circuit 34, and a CPU 36. The voltage detection circuit 32 is a circuit for detecting each voltage of the plurality of battery cells S1 to S6 connected in series. The voltage detection circuit 32 includes an ASIC (Application Specific Integrated Circuit) that is a dedicated custom IC. The voltage detection circuit 32 includes a plurality of voltage input terminals VP1 to VP7 for detecting respective voltages of the plurality of battery cells S1 to S6. In order to simplify the drawing, other terminals are omitted.

  Each node of the plurality of battery cells S1 to S6 and the plurality of voltage input terminals VP1 to VP7 of the voltage detection circuit 32 are connected by voltage detection lines L1 to L7, respectively. The inside of the battery management device 30 is constituted by printed wiring, and the outside is constituted by the wire harness 20.

  Discharge switches Q1 to Q6 are connected between adjacent two of the plurality of voltage detection lines L1 to L7, respectively. Various switching elements can be used for the discharge switch. In this specification, it is assumed that a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) with low on-resistance and low power consumption is used.

  In the example shown in FIG. 1, an n-channel MOSFET as the first discharge switch Q1 is connected between the first voltage detection line L1 and the second voltage detection line L2. More specifically, the source terminal of the n-channel MOSFET is connected to the second voltage detection line L2, the gate terminal is connected to the discharge control circuit 34, and the drain terminal is connected to the first voltage detection line L1 via the first discharge resistor R1. Connected.

  Between the second voltage detection line L2 and the third voltage detection line L3, between the third voltage detection line L3 and the fourth voltage detection line L4,... Between the sixth voltage detection line L6 and the seventh voltage detection line L7. Similarly, the second discharge switch Q2, the third discharge switch Q3,..., The sixth discharge switch Q6 are connected to each other.

  The plurality of voltage detection lines L1 to L7 are connected to the plurality of voltage input terminals VP1 to VP7 of the voltage detection circuit 32 through low-pass filters, respectively. In the example shown in FIG. 1, the low-pass filter is configured by an RC circuit. Specifically, resistors R11 to R17 are connected in series to the plurality of voltage detection lines L1 to L7, respectively, and between the first voltage detection line L1 and the second voltage detection line L2, the second voltage detection line L2 and the third voltage. A first capacitor C1, a second capacitor C2,..., A sixth capacitor C6 are connected between the detection lines L3,..., And between the sixth voltage detection line L6 and the seventh voltage detection line L7, respectively.

  The discharge control circuit 34 is a circuit for turning on / off the plurality of discharge switches Q1 to Q6. The CPU 36 controls the entire battery management device 30. The CPU 36 acquires the respective voltages of the plurality of battery cells S1 to S6 from the voltage detection circuit 32, and causes the discharge control circuit 34 to equalize the amount of charge (SOC; State Of Charge) of the plurality of battery cells S1 to S6. ON / OFF of the plurality of discharge switches Q1 to Q6 is set. Specifically, among the plurality of battery cells S1 to S6, a discharge switch connected in parallel with a battery cell having a higher voltage than the other battery cells is set to ON. Thereby, it discharges from the said battery cell via the discharge resistance and discharge switch connected in parallel with the said battery cell, and SOC of several battery cell S1-S6 is equalize | homogenized.

  The discharge control circuit 34 performs switch control for equalizing the charge amounts of the plurality of battery cells S1 to S6 based on an instruction from the CPU 36, and also performs the following control in this specification. That is, when there is an unconnected voltage detection line at the node of the battery cell among the plurality of voltage detection lines L1 to L7, the discharge control circuit 34 is a voltage whose potential is fixed to the unconnected voltage detection line. The discharge switch between the two voltage detection lines is turned on so that the detection line becomes conductive. When two or more voltage detection lines are separated from each other, all the plurality of discharge switches between them are turned on. Thereby, the potential of the unconnected and open voltage detection line can be fixed.

  When the battery management device 30 is activated, the CPU 36 instructs the discharge control circuit 34 to turn on the discharge switch necessary to fix the potential of the unconnected voltage detection line. The discharge switch to be turned on at the time of starting is specified by software. The CPU 36 executes the software at the time of activation to identify a discharge switch that should be always turned on and set it in the discharge control circuit 34.

  In the power supply device 100 shown in FIG. 1, there is no voltage detection line that is not connected to the node of the battery cell. Therefore, the above-described control (hereinafter referred to as “unconnected internal short-circuit process”) is not required to always turn on the discharge switch in order to fix the potential of the unconnected voltage detection line. Hereinafter, control when an unconnected voltage detection line is generated will be described with a specific example.

  FIG. 2 is a diagram for explaining the power supply device 100 when the number of mounted battery cells is one less than the number of management cells of the voltage detection circuit 32 (part 1). The assembled battery 10 shown in FIG. 2 has a configuration in which the second battery cell S2 is removed from the assembled battery 10 shown in FIG. That is, in this example, the number of management cells in the voltage detection circuit 32 is 6, and the number of battery cells to be mounted is 5. Note that the number of management cells indicates the maximum number of cells that can be managed by the voltage detection circuit 32.

  In the power supply device 100 shown in FIG. 2, the wire harness portions of the second voltage detection line L2 and the third voltage detection line L3 are left as they are. In this configuration, when the first battery cell S1 is discharged, a current flows through a path of the first voltage detection line L1 → the first discharge resistor R1 → the first discharge switch Q1 → the second voltage detection line L2. When discharging the third battery cell S3, a current flows through a path of the third voltage detection line L3 → the third discharge resistor R3 → the third discharge switch Q3 → the third voltage detection line L3.

  Since there is no open voltage detection line that is not connected to the node of the battery cell in the power supply device 100 shown in FIG. 2, the unconnected internal short circuit process is not necessary as in the power supply device 100 shown in FIG. 1. However, the second voltage detection line L2 and the third voltage detection line L3 are at the same potential, and any one of the lines is an unnecessary line. Therefore, a redundant wire harness exists.

  FIG. 3 is a diagram for explaining the power supply apparatus 100 when the number of battery cells to be mounted is one less than the number of management cells of the voltage detection circuit 32 (part 2). Compared with the power supply apparatus 100 shown in FIG. 2, the power supply apparatus 100 shown in FIG. 3 has a configuration in which the wire harness portion of the second voltage detection line L2 is omitted. In this configuration, the tip of the second voltage detection line L2 is not connected.

  The discharge control circuit 34 controls the second discharge switch Q2 to be always on to make the second voltage detection line L2 and the third voltage detection line L3 conductive. As a result, the potential of the second voltage detection line L2 is fixed to the node potential between the first battery cell S1 and the third battery cell S3, similarly to the third voltage detection line L3. Note that instead of the second discharge switch Q2, the first discharge switch Q1 may be controlled to be always on so that the second voltage detection line L2 and the first voltage detection line L1 are made conductive. In this way, the unconnected voltage detection line may be connected to any one of the adjacent upper and lower voltage detection lines.

  In the configuration in which the second discharge switch Q2 is always turned on as described above, the discharge current is reduced when discharging the first battery cell S1. Specifically, when the first battery cell S1 is discharged, the first discharge switch Q1 is turned on. In this case, the first voltage detection line L1 → the first discharge resistor R1 → the first discharge switch Q1 → the second discharge. A current flows through the path of the resistor R2 → the second discharge switch Q2 → the third voltage detection line L3. Thus, the discharge current path of the first battery cell S1 has twice the impedance compared to the discharge current paths of the other battery cells, and the discharge current flowing from the first battery cell S1 flows from the other battery cells. It becomes 1/2 of the discharge current.

  If the discharge current becomes too small, the time until the remaining capacity becomes equal to the other battery cells becomes longer. The potential of the first discharge switch Q1 is a potential obtained by dividing the potential of the first battery cell S1 by the first discharge resistor R1 and the second discharge resistor R2. Accordingly, when the voltage of the first battery cell S1 is low, the first discharge switch Q1 cannot be turned on.

  The power supply device 100 shown in FIG. 3 has the above-described restrictions, but the above-described unconnected internal short-circuit control can be applied if the restrictions can be allowed.

  FIG. 4 is a diagram for explaining the power supply device 100 when the number of battery cells to be mounted is one less than the number of management cells of the voltage detection circuit 32 (part 3). The assembled battery 10 shown in FIG. 4 has a configuration in which the first battery cell S1 is removed from the assembled battery 10 shown in FIG. The assembled battery 10 shown in FIG. 4 is different from the assembled battery 10 shown in FIGS. 2 and 3 in that the battery cell S1 at the extreme end on the high potential side is removed. The power supply device 100 shown in FIG. 4 has a configuration in which the wire harness portion of the first voltage detection line L1 is omitted. In this configuration, the tip of the first voltage detection line L1 is not connected. In this configuration, there is no wire harness having the same potential.

  The discharge control circuit 34 controls the first discharge switch Q1 to be always on, and makes the first voltage detection line L1 and the second voltage detection line L2 conductive. Accordingly, the potential of the first voltage detection line L1 is fixed to the potential on the positive electrode terminal side of the second battery cell S2, similarly to the second voltage detection line L2.

  In the power supply device 100 shown in FIG. 4, when the second battery cell S2 is discharged, a current flows through the path of the second voltage detection line L2, the second discharge resistance R2, the second discharge switch Q2, and the third voltage detection line L3. The impedance of the discharge current path is the same as the impedance of the discharge current path of the other battery cells, and the above-described restriction does not occur in the power supply device 100 shown in FIG.

  However, when the power source of the voltage detection circuit 32 and the discharge control circuit 34 is obtained from the assembled battery 10 and the first discharge switch Q1 is configured by an n-channel MOSFET, a gate voltage for turning on the first discharge switch Q1 can be secured. Disappear.

  As a countermeasure against this, the first discharge switch Q1 is constituted by a p-channel MOSFET instead of an n-channel MOSFET. Specifically, the source terminal of the p-channel MOSFET is connected to the first voltage detection line L1, the gate terminal is connected to the discharge control circuit 34, and the drain terminal is connected to the second voltage detection line L2 via the first discharge resistor R1. Connected. Accordingly, the first discharge switch Q1 can be turned on with a voltage within the voltage range of the battery pack 10.

  Even if the first discharge switch Q1 is composed of an n-channel MOSFET, the first discharge switch Q1 can be turned on if a gate voltage higher than the voltage of the assembled battery 10 is generated from a power source other than the assembled battery 10. However, since the voltage of the assembled battery 10 for in-vehicle use becomes a high voltage exceeding 100 V, generating a voltage higher than the assembled battery 10 from a power source other than the assembled battery 10 requires a large-scale addition of hardware.

  In the power supply device 100 shown in FIG. 4, the above-described unconnected internal short-circuiting process can be applied without providing additional hardware by configuring the first discharge switch Q1 with a p-channel MOSFET.

  FIG. 5 is a diagram for explaining the power supply device 100 when the number of battery cells to be mounted is one less than the number of management cells of the voltage detection circuit 32 (part 4). The assembled battery 10 shown in FIG. 5 has a configuration in which the sixth battery cell S6 is removed from the assembled battery 10 shown in FIG. Unlike the assembled battery 10 shown in FIGS. 2 to 4, the assembled battery 10 shown in FIG. 5 has a configuration in which the sixth battery cell S6 at the end on the low potential side is removed. The power supply device 100 shown in FIG. 5 has a configuration in which the wire harness portion of the seventh voltage detection line L7 is omitted. In this configuration, the tip of the seventh voltage detection line L7 is not connected. In this configuration, there is no wire harness having the same potential.

  The discharge control circuit 34 controls the sixth discharge switch Q6 to be always on to make the seventh voltage detection line L7 and the sixth voltage detection line L6 conductive. Accordingly, the potential of the seventh voltage detection line L7 is fixed to the potential on the negative electrode terminal side of the fifth battery cell S5, similarly to the sixth voltage detection line L6.

  In a general design, the negative electrode potential of the battery cell having the lowest potential of the assembled battery 10 is also used as the ground of the voltage detection circuit 32. Therefore, the circuit configuration of the power supply apparatus 100 shown in FIG. 5 is usually not adopted.

  FIG. 6 is a diagram for explaining the power supply device 100 when the number of battery cells to be mounted is two less than the number of management cells of the voltage detection circuit 32 (part 1). The assembled battery 10 shown in FIG. 6 has a configuration in which the second battery cell S2 and the third battery cell S3 are removed from the assembled battery 10 shown in FIG. That is, in this example, the number of management cells in the voltage detection circuit 32 is 6, and the number of battery cells to be mounted is 4. The power supply device 100 shown in FIG. 6 has a configuration in which the wire harness portion of the third voltage detection line L3 is omitted. In this configuration, the tip of the third voltage detection line L3 is not connected.

  The discharge control circuit 34 controls the third discharge switch Q3 to be always on to make the third voltage detection line L3 and the fourth voltage detection line L4 conductive. Thereby, the potential of the third voltage detection line L3 is fixed to the node potential between the first battery cell S1 and the fourth battery cell S4, similarly to the fourth voltage detection line L4.

  In the power supply device 100 shown in FIG. 6, when the first battery cell S1 is discharged, a current flows through the path of the first voltage detection line L1 → the first discharge resistor R1 → the first discharge switch Q1 → the second voltage detection line L2. When the fourth battery cell S4 is discharged, a current flows through the path of the fourth voltage detection line L4 → the fourth discharge resistor R4 → the fourth discharge switch Q4 → the fifth voltage detection line L5. The impedance of both discharge current paths is the same as the impedance of the discharge current paths of the other battery cells, and the above-described restriction does not occur in the power supply device 100 shown in FIG.

  In the power supply apparatus 100 shown in FIG. 6, the above-mentioned unconnected internal short-circuit process can be suitably applied. Since the wire harness portions of the second voltage detection line L2 and the fourth voltage detection line L4 are at the same potential, one of them should be omitted originally, but the discharge currents of the first battery cell S1 and the fourth battery cell S4 Are combined separately with the discharge currents of the other battery cells.

  FIG. 7 is a diagram for explaining the power supply device 100 when the number of battery cells to be mounted is two less than the number of management cells of the voltage detection circuit 32 (part 2). The assembled battery 10 shown in FIG. 7 has a configuration in which the first battery cell S1 and the second battery cell S2 are removed from the assembled battery 10 shown in FIG. Unlike the assembled battery 10 shown in FIG. 6, the assembled battery 10 shown in FIG. 7 has a configuration in which two battery cells S1 and S2 are removed in order from the extreme end on the high potential side. The power supply device 100 shown in FIG. 7 has a configuration in which the wire harness portions of the first voltage detection line L1 and the second voltage detection line L2 are omitted. In this configuration, the tips of the first voltage detection line L1 and the second voltage detection line L2 are not connected. In this configuration, there is no wire harness having the same potential.

  The discharge control circuit 34 controls the first discharge switch Q1 and the second discharge switch Q2 to be always on, and makes all of the first voltage detection line L1, the second voltage detection line L2, and the third voltage detection line L3 conductive. Accordingly, the potentials of the first voltage detection line L1 and the second voltage detection line L2 are fixed to the potential on the positive electrode terminal side of the third battery cell S3, similarly to the third voltage detection line L3.

  In the power supply device 100 shown in FIG. 7, the first discharge switch Q1 and the second discharge switch Q2 are configured by p-channel MOSFETs instead of n-channel MOSFETs. Thereby, the 1st discharge switch Q1 and the 2nd discharge switch Q2 can be turned on with the voltage within the voltage range of the assembled battery 10.

  In the power supply apparatus 100 shown in FIG. 7, the first discharge switch Q1 and the second discharge switch Q2 are configured by p-channel MOSFETs, so that the above-described unconnected line internal short-circuiting process can be applied without providing additional hardware.

  As in the power supply device 100 shown in FIGS. 4 and 7, at least one of the plurality of discharge switches Q1 to Q6 is configured with a p-channel MOSFET from the high potential side, and the remaining discharge switches are formed with an n-channel MOSFET. The configuration has the following advantages. That is, regardless of the position of the battery cell, all of the plurality of discharge switches Q1 to Q6 can be driven with a voltage within the voltage range of the assembled battery 10. In the case of a design in which the battery cell on the highest potential side is not omitted, all the discharge switches Q1 to Q6 can be configured with n-channel MOSFETs. Further, the number of discharge switches to be configured with p-channel MOSFETs corresponds to the number of battery cells that are continuously omitted from the high potential side.

  FIG. 8 is a diagram for explaining the power supply device 100 when the number of battery cells to be mounted is three less than the number of management cells of the voltage detection circuit 32. The assembled battery 10 shown in FIG. 8 has a configuration in which the second battery cell S2, the third battery cell S3, and the fourth battery cell S4 are removed from the assembled battery 10 shown in FIG. That is, the number of management cells of the voltage detection circuit 32 is 6 and the number of battery cells to be mounted is 3. The power supply device 100 shown in FIG. 8 has a configuration in which the wire harness portions of the third voltage detection line L3 and the fourth voltage detection line L4 are omitted. In this configuration, the tips of the third voltage detection line L3 and the fourth voltage detection line L4 are not connected.

  The discharge control circuit 34 controls the third discharge switch Q3 and the fourth discharge switch Q4 to be always on, and makes all the third voltage detection line L3, the fourth voltage detection line L4, and the fifth voltage detection line L5 conductive. Accordingly, the potentials of the third voltage detection line L3 and the fourth voltage detection line L4 are fixed to the node potential between the first battery cell S1 and the fifth battery cell S5, similarly to the fifth voltage detection line L5.

  In the power supply apparatus 100 shown in FIG. 8, the above-mentioned unconnected internal short-circuit process can be suitably applied. Since the wire harness portions of the second voltage detection line L2 and the fifth voltage detection line L5 have the same potential, one of them should be omitted originally, but the discharge currents of the first battery cell S1 and the fifth battery cell S5 Are combined separately with the discharge currents of the other battery cells.

  As described above, according to the embodiment, by turning on the internal discharge switch, an unconnected voltage detection line can be brought into conduction with a voltage detection line whose neighboring potential is fixed. Since the discharge switch for equalization control is used, the potential of the unconnected voltage detection line can be fixed without providing additional hardware. That is, there is no need to connect the unconnected terminals with a jumper outside the circuit or connect the unconnected terminals to the wire harness. Thus, cost and space can be saved.

  Moreover, since the discharge switch provided between the voltage detection lines to be conducted can be designated by software, the position of the discharge switch that is always turned on can be flexibly changed after the battery management device 30 is completely mounted. Therefore, it is easy to change the configuration of the assembled battery 10 after the completion of mounting. In this respect, in the design in which the potential of the unconnected voltage detection line is fixed using hardware, the change is not easy.

  Further, by using a MOSFET for the discharge switch, power consumption can be reduced as compared with the case of using another switching element such as a bipolar transistor. The power consumption of the MOSFET is negligibly small. In addition, by making at least one discharge switch from the high potential side into a p-channel type, even if the battery cell on the high potential side is omitted, the discharge switch on the high potential side is turned on with a voltage within the voltage range of the assembled battery 10. it can.

  When a plurality of battery cells are continuously pulled out, the wire harness part of the voltage detection line closest to the negative electrode side of the upper battery cell and the voltage detection line closest to the positive electrode side of the lower battery cell thereof It is preferable to leave the wire harness part. Although these two voltage detection lines have the same potential, by leaving both, the impedance of the discharge path of the upper battery cell, the discharge path of the lower battery cell, and the discharge path of the other battery cells can be made the same. The wire harness portion is omitted for the voltage detection line existing between the two voltage detection lines. Thereby, cost and space can be saved while maintaining the accuracy of equalization control.

  The present invention has been described based on the embodiments. Those skilled in the art will understand that these embodiments are exemplifications, and that various modifications can be made to the combinations of the respective constituent elements and processing processes, and such modifications are also within the scope of the present invention. By the way.

  In the above-described embodiment, the example in which the battery management device 30 is used for managing the in-vehicle secondary battery has been described. In this regard, the battery management device 30 can also be applied to a use for managing a storage battery in a stationary power storage system.

  100 power supply device, 10 assembled battery, S1 first battery cell, S2 second battery cell, S3 third battery cell, S4 fourth battery cell, S5 fifth battery cell, S6 sixth battery cell, 20 wire harness, L1 first 1 voltage detection line, L2 second voltage detection line, L3 third voltage detection line, L4 fourth voltage detection line, L5 fifth voltage detection line, L6 sixth voltage detection line, L7 seventh voltage detection line, 30 battery management Device, 32 voltage detection circuit, 34 discharge control circuit, 36 CPU, Q1 first discharge switch, Q2 second discharge switch, Q3 third discharge switch, Q4 fourth discharge switch, Q5 fifth discharge switch, Q6 sixth discharge switch R1 first discharge resistance, R2 second discharge resistance, R3 third discharge resistance, R4 fourth discharge resistance, R5 fifth discharge resistance R6 6th discharge resistor, R11 1st resistor, R12 2nd resistor, R13 3rd resistor, R14 4th resistor, R15 5th resistor, R16 6th resistor, R17 7th resistor, C1 1st capacitor, C2 2nd capacitor C3 3rd capacity, C4 4th capacity, C5 5th capacity, C6 6th capacity, 40 load.

Claims (5)

A voltage detection circuit for detecting each voltage of a plurality of battery cells connected in series;
A plurality of voltage detection lines for connecting each node of the plurality of battery cells and the voltage detection circuit;
A plurality of discharge switches respectively connected between two adjacent ones of the plurality of voltage detection lines;
A discharge control circuit that controls the plurality of discharge switches in order to equalize the amount of charge of the plurality of battery cells,
In the discharge control circuit, when there is an unconnected voltage detection line at the node of the battery cell among the plurality of voltage detection lines, the unconnected voltage detection line and a voltage detection line in which an adjacent potential is fixed The battery management device is set at the time of starting the battery management device so as to perform control to always turn on the discharge switch between the two voltage detection lines so as to be conductive.   The battery management apparatus according to claim 1, wherein a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) is used for the discharge switch.   3. The battery according to claim 1, wherein a p-channel MOSFET is used for at least one discharge switch from a high potential side among a plurality of discharge switches connected respectively between the plurality of voltage detection lines. Management device. A processor that obtains voltages of the plurality of battery cells from the voltage detection circuit and sets on / off of the plurality of discharge switches in the discharge control circuit so as to equalize a charge amount of the plurality of battery cells; Prepared,
The processor, when starting up the battery management apparatus, instructs the discharge control circuit to turn on the discharge switch necessary for fixing the potential of the unconnected voltage detection line. The battery management apparatus according to any one of 1 to 3. An assembled battery in which a plurality of battery cells are connected in series;
The battery management device according to any one of claims 1 to 4, which manages the assembled battery;
A power supply apparatus comprising:

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