JP2018189370A - Voltage detection circuit and power storage system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect earlier a break of a voltage measurement line between a plurality cells connected in series and a voltage detection circuit.SOLUTION: A voltage detection circuit (11) is connected to each node between a plurality of series-connected storage cells (B1 to B5) via a plurality of voltage measurement lines (L0 to L5), and detect the voltage between adjacent voltage measurement lines and detects the voltage of each storage cell (B1 to B5). Between adjacent voltage measurement lines of the plurality of voltage measurement lines (L0 to L5), capacitors (C1 to C5) are connected in parallel to respective storage cells (B1 to B5). Impedance elements (R1u, R3u, R5u) are connected in parallel to the capacitors (C1, C3, C5) every other capacitor among the plurality of capacitors (C1 to C5).SELECTED DRAWING: Figure 2

Description

  The present invention relates to a voltage detection circuit and a power storage system.

  In recent years, power storage systems using lithium ion batteries have become widespread for in-vehicle use, backup and peak shift applications. 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 (see, for example, Patent Document 1).

  Each node between a plurality of battery cells connected in series and the voltage detection circuit are connected by a voltage measurement line, respectively, and the voltage detection circuit detects a voltage across each battery cell. In order to stabilize the detection potential of each voltage measurement line, a configuration in which a capacitor is connected between two adjacent voltage measurement lines in a plurality of voltage measurement lines is common.

  In this configuration, even when a certain voltage measurement line is disconnected, the potential of the voltage measurement line does not immediately decrease to an abnormal level. That is, immediately after the disconnection, the potential of the disconnected voltage measurement line is changed between the voltage measurement line adjacent to the upper side by the capacitor between the voltage measurement line adjacent to the upper side and the capacitor between the voltage measurement line adjacent to the lower side. It is maintained near the midpoint potential of the voltage between the voltage measurement lines adjacent to the lower side. Thereafter, as the electric charge accumulated in both capacitors is released, the potential of the disconnected voltage measurement line is lowered.

JP 2014-149161 A

  As described above, a time lag occurs after the voltage measurement line is disconnected until the voltage detection circuit detects the disconnection. During this period, the battery is operated in a state where the battery cell connected to the disconnected voltage measurement line cannot be detected by the voltage detection circuit even if overcharge or overdischarge occurs.

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a technique for detecting earlier disconnection of a voltage measurement line between a plurality of cells connected in series and a voltage detection circuit.

  In order to solve the above problems, a voltage detection circuit according to an aspect of the present invention is connected to each node between a plurality of storage cells connected in series with a plurality of voltage measurement lines, and detects a voltage between adjacent voltage measurement lines. A voltage detection circuit that detects and detects the voltage of each storage cell, wherein a capacitor is connected in parallel with each storage cell between adjacent voltage measurement lines of the plurality of voltage measurement lines, and the voltage detection circuit , And every other capacitor is provided with an impedance element connected in parallel with the capacitor.

  It should be noted that any combination of the above-described constituent elements and a representation of the present invention converted between a method, an apparatus, a system, and the like are also effective as an aspect of the present invention.

  According to the present invention, disconnection of the voltage measurement line between the plurality of cells connected in series and the voltage detection circuit can be detected earlier.

It is a figure for demonstrating the electrical storage system which concerns on the comparative example 1. FIG. It is a figure for demonstrating the electrical storage system which concerns on Embodiment 1 of this invention. 6 is a diagram for explaining a power storage system according to Comparative Example 2. FIG. It is a figure for demonstrating the electrical storage system which concerns on Embodiment 2 of this invention. 10 is a diagram for explaining a power storage system according to Comparative Example 3. FIG. It is a figure for demonstrating the electrical storage system which concerns on Embodiment 3 of this invention. It is a figure for demonstrating the electrical storage system which concerns on a modification.

  FIG. 1 is a diagram for explaining a power storage system 1 according to Comparative Example 1. The power storage system 1 includes an assembled battery 20 and a battery management device 10, and the assembled battery 20 supplies power to the load 2. In the case of in-vehicle use, the load 2 is a motor, and regenerative energy generated by the motor is charged to the assembled battery 20 during deceleration.

  The assembled battery 20 includes a plurality of battery cells B1 to B5 connected in series. In Comparative Example 1, an assembled battery 20 is assumed in which five battery cells B1 to B5 are connected in series. Further, a lithium ion battery is assumed as the type of battery.

  The battery management device 10 includes a voltage detection circuit 11 and a control circuit 12. The voltage detection circuit 11 is connected to each node between a plurality of battery cells B1 to B5 connected in series and a plurality of voltage measurement lines L0 to L5, and detects a voltage between adjacent voltage measurement lines to detect each battery cell B1. The voltage of ~ B5 is detected. The voltage detection circuit 11 is configured by, for example, an ASIC (Application Specific Integrated Circuit) that is a dedicated custom IC.

  Resistors R0 to R5 are inserted into the plurality of voltage measurement lines L0 to L5, respectively. A discharge circuit is connected between two adjacent voltage measurement lines of the plurality of voltage measurement lines L0 to L5. Each discharge circuit includes a series circuit of discharge switches S1d to S5d and discharge resistors R1d to R5d. The discharge circuit is mainly used for equalization control of the plurality of battery cells B1 to B5.

  Capacitors C1 to C5 are connected in parallel with the plurality of battery cells B1 to B5 between two adjacent voltage measurement lines of the plurality of voltage measurement lines L0 to L5, respectively. Capacitors C1 to C5 are responsible for stabilizing each potential of the plurality of voltage measurement lines L0 to L5.

  The battery management device 10 includes a plurality of path selection switches S0 to S5 controlled by the plurality of voltage measurement lines L0 to L5, respectively, and an A / D converter 111. The plurality of path selection switches S <b> 0 to S <b> 5 select any two voltage measurement lines, and input the potentials of the two voltage measurement lines to the A / D converter 111. The A / D converter 111 converts a potential difference between two input potentials into a digital value and outputs the digital value to the control circuit 12.

  This configuration example is an example in which the voltages of the plurality of battery cells B1 to B5 are measured in a time division manner. For example, the first voltage measurement line L0 and the first voltage measurement line L1 are first selected to measure the voltage of the first battery cell B1, and then the first voltage measurement line L1 and the second voltage measurement line L2 are selected. Then, the voltage of the second battery cell B2 is measured, and finally the fourth voltage measurement line L4 and the fifth voltage measurement line L5 are selected to measure the voltage of the fifth battery cell B5. By repeating this process, a plurality of battery cells B1 to B5 can be measured by one A / D converter 111, and the cost and circuit area of the voltage detection circuit 11 can be reduced.

  In addition, you may provide an A / D converter in all between two voltage measurement lines which the voltage measurement lines L0-L5 adjoin. In this case, the plurality of route selection switches S0 to S5 are not necessary.

  The control circuit 12 controls the battery management apparatus 10 as a whole. The configuration of the control circuit 12 can be realized by cooperation of hardware resources and software resources, or only by hardware resources. As hardware resources, analog circuits, logic circuits, microcomputers, DSPs, ROMs, RAMs, FPGAs, and other LSIs can be used. Firmware and other programs can be used as software resources.

  The control circuit 12 acquires the voltage values of the plurality of battery cells B <b> 1 to B <b> 5 from the voltage detection circuit 11. For example, signals are transmitted and received between the voltage detection circuit 11 and the control circuit 12 by communication using an insulation interface. The control circuit 12 monitors whether overvoltage / undervoltage has occurred in any of the plurality of battery cells B1 to B5. When overvoltage / undervoltage is detected, the control circuit 12 notifies an alert to the host device. In the case of in-vehicle use, the ECU is notified as a host device.

  As described above, when adopting a configuration in which the channels connected to the A / D converter 111 are sequentially switched by turning on / off the plurality of path selection switches S0 to S5, the control circuit 12 has the plurality of path selection switches S0 to S5. Toggle on / off sequentially.

  In addition, the control circuit 12 has an equalization control function and periodically performs equalization control of the plurality of battery cells B1 to B5. For example, the voltage of the other battery cell is adjusted to the voltage of the battery cell having the lowest voltage among the plurality of battery cells B1 to B5. Specifically, the discharge switch of the other battery cell is turned on to discharge the other battery cell. When the voltage of the other battery cell reaches the voltage of the battery cell having the lowest voltage, the discharge switch of the other battery cell is turned off.

  Consider a situation in which one voltage measurement line (second voltage measurement line L2 in FIG. 1) is disconnected in the above configuration. Even if the second voltage measurement line L2 is disconnected, the voltages of the second battery cell B2 and the third battery cell B3 do not immediately become abnormal levels and remain in the normal range for a certain period. During this period, the overvoltage / undervoltage of the second battery cell B2 or the third battery cell B3 cannot be detected, and the battery is not sufficiently protected.

  The reason why the voltages of the second battery cell B2 and the third battery cell B3 do not immediately become abnormal levels is that the impedance between the first voltage measurement line L1 and the third voltage measurement line L3 above and below the disconnection point is balanced and the second capacitor This is because the charges in C2 and the third capacitor C3 are not immediately released. That is, the potential of the node Na between the second capacitor C2 and the third capacitor C3 is maintained near the potential before the disconnection. The charges in the second capacitor C2 and the third capacitor C3 gradually escape due to the wiring resistance in the voltage detection circuit 11, but it takes time. During this period, the protection of the battery is inadequate, and an immediate response is required particularly for in-vehicle applications. Therefore, it is required to eliminate such a period.

  FIG. 2 is a diagram for explaining the power storage system 1 according to Embodiment 1 of the present invention. Hereinafter, differences between the power storage system 1 according to Embodiment 1 shown in FIG. 2 and the power storage system 1 according to Comparative Example 1 in FIG. 1 will be described. In the first embodiment, an unbalanced resistor is connected in parallel with every other capacitor among the plurality of capacitors C1 to C5. In the example shown in FIG. 2, the first unbalance resistor R1u is connected between the zeroth voltage measurement line L0 and the first voltage measurement line L1 to which the first capacitor C1 is connected, and the second capacitor C3 is connected. A third unbalance resistor R3u is connected between the voltage measurement line L2 and the third voltage measurement line L3, and a fifth unbalance is established between the fourth voltage measurement line L4 and the fifth voltage measurement line L5 to which the fifth capacitor C5 is connected. Resistor R5u is connected. Of the capacitors C1 to C5, unbalanced resistors R1u and R5u are connected to the capacitors C1 and C5 at both ends.

  Consider a situation in which the second voltage measurement line L2 is disconnected as in the first comparative example. When the second voltage measurement line L2 is disconnected, the energy in the third capacitor C3 is consumed by the third unbalance resistor R3u, so that the potential of the node Na between the second capacitor C2 and the third capacitor C3 is immediately increased (first Sticks to the potential of the three voltage measurement line L3). Accordingly, the voltage of the second battery cell B2 is about twice as high as normal, and the voltage of the third battery cell B3 becomes almost zero. That is, since the impedance between the first voltage measurement line L1 and the third voltage measurement line L3 above and below the disconnection portion becomes unbalanced, the potential of the node Na between the second capacitor C2 and the third capacitor C3 is immediately attached to the top. Become.

  When the third voltage measurement line L3 is disconnected, the energy in the third capacitor C3 is consumed by the third unbalance resistor R3u, so that the potential of the node between the third capacitor C3 and the fourth capacitor C4 is immediately lowered (first Sticks to the potential of the three voltage measurement line L3).

  The control circuit 12 can turn on the discharge switches S1d to S5d to draw out the electric charges accumulated in the capacitors C1 to C5 through the discharge resistors R1d to R5d. Such a phase may be inserted periodically. Further, the control circuit 12 can detect disconnection of the voltage measurement line by the same principle as described above by turning on every other discharge switch S1d to S5d. Such a phase may be inserted periodically.

  As described above, according to the first embodiment, by providing a resistor for every other measurement channel of the voltage detection circuit 11, the charge on one of the capacitors above and below the disconnected voltage measurement line is intentionally extracted. Can do. Accordingly, the potential of the disconnected voltage measurement line can be instantaneously attached to the upper side or the lower side, and the voltage detection circuit 11 can instantaneously detect the disconnection of the voltage measurement line. Further, it is sufficient to add a resistance which is a passive element, and no additional active element is necessary. Since the number of parts to be added is small, this technology can be introduced at a low cost and the failure rate can be kept low.

  In addition, if a phase for turning on every other discharge switch S1d to S5d is added, even if there is a problem in detecting disconnection of the voltage measurement line due to unbalanced resistance, etc., the disconnection is detected in this phase. Can do. Adopting this method provides double protection against disconnection of the voltage measurement line.

  In the first embodiment, an example in which the number of battery cells and the number of capacitors connected in parallel to each battery cell is an odd number has been described. In the second embodiment, an example in which the number is an even number will be described.

  FIG. 3 is a diagram for explaining the power storage system 1 according to the second comparative example. In Comparative Example 2, an assembled battery 20 is assumed in which four battery cells B1 to B4 are connected in series. Consider a situation in which the fourth voltage measurement line L4 on the side to which the unbalanced resistor is not connected is disconnected among the voltage measurement lines L0 and L4 at both ends in the above configuration. In this case, since the energy in the fourth capacitor C4 cannot be consumed by the unbalanced resistor, it takes time until the energy in the fourth capacitor C4 is consumed.

  As shown in FIG. 2, when the number of battery cells is an odd number, an unbalanced resistor is connected to capacitors C1 and C5 at both ends of a plurality of capacitors C1 to C5 while observing the rule of inserting an unbalanced resistor every other cell. can do. On the other hand, when the number of battery cells is an even number as shown in FIG. 3, if the rule for inserting an unbalanced resistor every other is observed, the unbalanced resistor is not connected to the capacitor C4 at one end.

  FIG. 4 is a diagram for explaining a power storage system 1 according to Embodiment 2 of the present invention. Hereinafter, differences between power storage system 1 according to Embodiment 2 shown in FIG. 4 and power storage system 1 according to Comparative Example 2 shown in FIG. 3 will be described. In the second embodiment, among the two capacitors C1 and C4 at both ends, the adjustment unbalance resistor R4u is also connected to the capacitor C4 to which the unbalance resistor is not originally connected when the above rule is observed.

  At this time, the resistance values of the unbalance resistor inserted in compliance with the above rules and the adjustment unbalance resistor are set to different values. In the example shown in FIG. 4, three adjustment unbalance resistors R4u are connected in series in parallel with the fourth capacitor C4. That is, the ratio of the resistance value between the second voltage measurement line L2 and the third voltage measurement line L3 and the resistance value between the third voltage measurement line L3 and the fourth voltage measurement line L4 is 1: 3. The same is true even when one adjustment unbalance resistor R4u having a resistance value three times the resistance value of the third unbalance resistor R3u is used.

  Hereinafter, a situation in which the third voltage measurement line L3 is disconnected will be considered. When the third voltage measurement line L3 is disconnected, the energy in the third capacitor C3 is consumed by the third unbalance resistor R3u, and the energy in the fourth capacitor C4 is consumed by the adjustment unbalance resistor R4u. At this time, since the resistance value of the adjustment unbalance resistor R4u is larger, the energy in the fourth capacitor C4 is consumed earlier. The voltage between the second voltage measurement line L2 and the fourth voltage measurement line L4 is 1: 3, the voltage of the third battery cell B3 falls below the lower limit of the normal range, and the voltage detection circuit 11 detects an abnormality.

  When the fourth voltage measurement line L4 is disconnected, the energy in the fourth capacitor C4 is consumed by the adjustment unbalance resistor R4u. In this case, the voltage of the fourth battery cell B4 exceeds the upper limit of the normal range, and the voltage detection circuit 11 detects an abnormality.

  As described above, according to the second embodiment, even when the number of battery cells is an even number, by connecting the adjustment unbalance resistor R4u to the capacitor C4 at the end to which the unbalance resistor is not originally connected, Even when the voltage measurement line L4 at the end to which the unbalanced resistor is not originally connected is broken, it can be detected instantaneously. Other effects are the same as those of the first embodiment.

  The number of battery cells of the assembled battery 20 varies and differs depending on the application and specifications. Even for in-vehicle use, it differs for each vehicle type. It is ideal that the chip manufacturer prepares the voltage detection circuit 11 individually for each assembled battery 20 having a different number of battery cells, but the manufacturing cost and management cost increase. Therefore, even when the number of terminals of the voltage measurement line of the voltage detection circuit 11 does not match the number of battery cells, the voltage detection circuit may be used if the number of terminals is larger than the number of battery cells. In the third embodiment, an example in which the number of battery cells is smaller than the number of terminals of the voltage measurement line of the voltage detection circuit 11 will be described.

  FIG. 5 is a diagram for explaining the power storage system 1 according to the third comparative example. In the comparative example 3, the third battery cell B3, the second resistor R2, the third capacitor C3, the third discharge switch S3d, and the third discharge resistor R3d are omitted from the configuration of the power storage system 1 in FIG. That is, this is an example in which the number of battery cells is 4 and the number of terminals of the voltage measurement line of the voltage detection circuit 11 is 6. By skipping the third channel of the voltage detection circuit 11, the four battery cells B1, B2, B4, B5 are voltage. Connected to the detection circuit 11. In this circuit configuration, when the third voltage measurement line L3 is disconnected, the energy in the second capacitor C2 and the fourth capacitor C4 cannot be consumed by the unbalanced resistor, and thus the second capacitor C2 and the fourth capacitor C4 It takes time for energy to be consumed.

  FIG. 6 is a diagram for explaining a power storage system 1 according to Embodiment 3 of the present invention. In the third embodiment, the unbalanced resistor is connected in parallel with every other one or more of the plurality of capacitors. At that time, two adjacent unbalanced resistors are connected between the respective voltage measurement lines via switches.

  In the example shown in FIG. 6, a series circuit of a third unbalance resistor R3u and a third resistor selection switch S3u is connected between the second voltage measurement line L2 (not connected to the storage cell) and the third voltage measurement line L3. A series circuit of a fourth unbalance resistor R4u and a fourth resistor selection switch S4u is connected between the third voltage measurement line L3 and the fourth voltage measurement line L4.

  When a series circuit of an unbalance resistor and a resistance selection switch is connected to a voltage measurement line that is not connected to a node between battery cells, the switch is set to off and the unbalance resistor is invalidated. In FIG. 6, the third resistance selection switch S3u connected to the second voltage measurement line L2 is set to OFF. When there is no capacitor connected in parallel with the series circuit of the unbalance resistor and the resistance selection switch, it may be considered that the unbalance resistance is invalidated by setting the resistance selection switch to OFF.

  According to the rule of connecting an unbalanced resistor to every other capacitor C1, C2, C4, C5, the unbalanced resistor is connected in parallel with the first capacitor C1 and the fourth capacitor C4 in FIG. become. Therefore, the fourth resistance selection switch S4u between the third voltage measurement line L3 and the fourth voltage measurement line L4 is set to ON, and the fourth unbalance resistance R4u is made effective.

  Further, since the circuit shown in FIG. 6 has an even number of battery cells, as described in the second embodiment, the unbalanced resistor is not originally connected when the above rule is observed among the two capacitors C1 and C5 at both ends. An adjustment unbalance resistor R5u is also connected to the other capacitor C5. The resistance value of the adjustment unbalance resistor R5u is set to a value different from the resistance value of the fourth unbalance resistor R4u.

  The on / off of the third resistance selection switch S3u and the fourth resistance selection switch S4u is preset and fixed at the time of shipment according to the number of battery cells of the assembled battery 20 to be used. When the power storage system 1 is started to be used, it is fixed from the logic circuit in the control circuit 12 to the control terminals of the third resistance selection switch S3u and the fourth resistance selection switch S4u (when using an FET as the switch). A configuration in which the level is continuously applied until the use of the power storage system 1 is completed may be employed.

  In FIG. 6, an example in which a series circuit of an unbalanced resistor and a resistance selection switch is connected to two adjacent channels has been described. However, the series circuit may be connected to three or more channels, or all channels may be connected. The series circuit may be connected. When the number of battery cells is an even number, the resistance value of the unbalance resistor connected to one end may be set to a value different from the resistance value of the other unbalance resistor.

  As described above, according to Embodiment 3, the number of channels of the voltage detection circuit 11 and the battery of the assembled battery 20 are connected by connecting a series circuit of an unbalance resistor and a resistance selection switch to two adjacent channels. Even in cases where the number of cells is different, disconnection of the voltage measurement line can be detected instantaneously. Other effects are the same as those of the first embodiment.

  The present invention has been described based on the embodiments. The embodiments are exemplifications, and it will be understood by those skilled in the art that various modifications can be made to combinations of the respective constituent elements and processing processes, and such modifications are within the scope of the present invention. .

  FIG. 7 is a diagram for explaining a power storage system 1 according to a modification. In the above-described embodiment, the configuration in which the impedance ratio between two adjacent measurement channels is destroyed by inserting an unbalanced resistor in every other measurement channel of the voltage detection circuit 11 has been described. In the modification, unbalanced resistors Ru1 to Ru5 are inserted into all measurement channels, and the two adjacent unbalanced resistors are designed to have different resistance values. This also provides the same effects as those of the above-described embodiment.

  In the above-described embodiment, an example has been described in which an unbalanced resistor is inserted into one channel in order to destroy the impedance ratio between two adjacent channels. In this regard, an impedance element other than a resistor may be used as long as the impedance ratio between the two channels can be destroyed. For example, a transistor whose gate or base is fixed to an on state may be used. The on-resistance of the transistor can break the impedance ratio between two adjacent channels. It is also conceivable that the impedance values between two adjacent discharge paths are made different by utilizing a resistance component due to wiring.

  Moreover, although the example using a lithium ion battery was assumed in the above-mentioned embodiment, you may use other types of batteries, such as a nickel metal hydride battery and a lead battery. A capacitor (for example, an electric double layer capacitor) may be used instead of the battery.

  The embodiment may be specified by the following items.

[Item 1]
Each node between the plurality of storage cells (B1 to B5) connected in series is connected to the plurality of voltage measurement lines (L0 to L5), and the voltage between the adjacent voltage measurement lines is detected to detect each storage cell (B1 to B1). A voltage detection circuit (11) for detecting the voltage of B5),
Capacitors (C1 to C5) are connected in parallel with the storage cells (B1 to B5) between adjacent voltage measurement lines of the plurality of voltage measurement lines (L0 to L5), respectively.
The voltage detection circuit (11)
A voltage detection circuit comprising impedance elements (R1u, R3u, R5u) connected in parallel with the capacitors (C1, C3, C5) every other capacitor among the plurality of capacitors (C1-C5). 11).
According to this, when the voltage measurement line is disconnected, the potential of the voltage measurement line can be instantly pasted up or down, and the detection timing of the disconnection can be advanced.
[Item 2]
When the number of the plurality of capacitors (C1 to C5) is an odd number, the plurality of impedance elements (R1u, R5u) are connected to the two capacitors (C1, C5) at both ends, respectively. 2. The voltage detection circuit (11) according to item 1, wherein every other R3u, R5u) is connected.
Thereby, even if which voltage measurement line (L0-L5) is disconnected, a disconnection can be detected instantaneously.
[Item 3]
When the number of the capacitors (C1 to C4) is an even number, of the two capacitors (C1, C4) at both ends, the capacitor (C4) that is not originally connected to the impedance element (R1u, R3u) is connected in parallel. It further includes an adjustment impedance element (R4u) to be connected,
The voltage detection circuit (11) according to item 1, wherein an impedance value of every other impedance element (R1u, R3u) connected to the impedance element of the adjustment impedance element (R4u) is different.
Thereby, even if the voltage measurement line at the end to which the impedance element is not originally connected is disconnected, the disconnection can be detected instantaneously.
[Item 4]
The impedance elements (R1u, R3u, R4u, R5u) are connected in parallel with every other capacitor (C1, C2, C4, C5) among the plurality of capacitors,
Among the plurality of impedance elements (R1u, R3u, R4u, R5u), at least one set of two adjacent impedance elements (R3u, R4u) is connected via a switch (S3u, S4u) between the respective voltage measurement lines. The voltage detection circuit (11) according to item 1, wherein the voltage detection circuit (11) is connected.
Thereby, a channel that can arbitrarily select whether or not to connect the impedance element can be provided, and the voltage detection circuit 11 and the assembled battery 20 can be flexibly combined.
[Item 5]
In the case where the number of channels of the voltage detection circuit (11) is larger than the number of the plurality of storage cells (B1, B2, B4, B5),
Among the plurality of voltage measurement lines (L0 to L5) of the voltage detection circuit (11), the impedance element (R3u) and the switch (S3u) are connected to the voltage measurement line (L2) not connected to the node between the storage cells. The voltage detection circuit (11) according to item 4, wherein the switch (S3u) is set to OFF when is connected.
[Item 6]
Each node between the plurality of storage cells (B1 to B5) connected in series is connected to the plurality of voltage measurement lines (L0 to L5), and the voltage between the adjacent voltage measurement lines is detected to detect each storage cell (B1 to B1). A voltage detection circuit (11) for detecting the voltage of B5),
Capacitors (C1 to C5) are connected in parallel with the storage cells (B1 to B5) between adjacent voltage measurement lines of the plurality of voltage measurement lines (L0 to L5), respectively.
The voltage detection circuit (11)
A plurality of discharge paths formed respectively in parallel with the plurality of capacitors (C1 to C5);
The voltage detection circuit (11), wherein in the plurality of discharge paths, impedance values between two adjacent discharge paths are different.
According to this, when the voltage measurement line is disconnected, the potential of the voltage measurement line can be instantly pasted up or down, and the detection timing of the disconnection can be advanced.
[Item 7]
Each node between the plurality of storage cells (B1 to B5) connected in series and a plurality of voltage measurement lines (L0 to L5) is detected, and a voltage between adjacent voltage measurement lines is detected to detect each storage cell (B1 to B1). A voltage detection circuit (11) for detecting the voltage of B5),
Capacitors (C1 to C5) are connected in parallel with the storage cells (B1 to B5) between adjacent voltage measurement lines of the plurality of voltage measurement lines (L0 to L5), respectively.
The voltage detection circuit (11)
A plurality of impedance elements (R1u to R5u) respectively connected in parallel with the plurality of capacitors (C1 to C5);
The voltage detection circuit (11), wherein in the plurality of impedance elements (R1u to R5u), impedance values between two adjacent impedance elements are different.
According to this, when the voltage measurement line is disconnected, the potential of the voltage measurement line can be instantly pasted up or down, and the detection timing of the disconnection can be advanced.
[Item 8]
A plurality of storage cells (B1 to B5) connected in series;
The voltage detection circuit (11) according to any one of items 1 to 6, which detects each voltage of the plurality of power storage cells (B1 to B5);
A power storage system (1) comprising:
According to this, when the voltage measurement line is disconnected, the potential of the voltage measurement line can be instantly pasted up or down, and the detection timing of the disconnection can be advanced.

  DESCRIPTION OF SYMBOLS 1 Power storage system, 2 Load, 10 Battery management apparatus, 11 Voltage detection circuit, 111 A / D converter, 12 Control circuit, 20 assembled battery, B1, B2, B3, B4, B5 battery cell, R0, R1, R2, R3, R4, R5 resistor, C1, C2, C3, C4, C5 capacitor, S0, S1, S2, S3, S4, S5 path selection switch, L0, L1, L2, L3, L4, L5 voltage measurement line, S1d, S2d, S3d, S4d, S5d discharge switch, R1d, R2d, R3d, R4d, R5d discharge resistance, R1u, R2u, R3u, R4u, R5u unbalanced resistance, S3u, S4u resistance selection switch.

Claims (8)

A voltage detection circuit that is connected to each node between a plurality of storage cells connected in series and a plurality of voltage measurement lines, detects a voltage between adjacent voltage measurement lines, and detects a voltage of each storage cell,
A capacitor is connected in parallel with each storage cell between adjacent voltage measurement lines of the plurality of voltage measurement lines,
The voltage detection circuit includes:
A voltage detection circuit comprising an impedance element connected in parallel with every other capacitor among the plurality of capacitors.   2. The plurality of impedance elements are alternately connected so that impedance elements are respectively connected to two capacitors at both ends when the number of the plurality of capacitors is an odd number. Voltage detection circuit. When the number of the plurality of capacitors is an even number, it further comprises an adjusting impedance element connected in parallel with the capacitor that is not originally connected to the impedance element among the two capacitors at both ends,
2. The voltage detection circuit according to claim 1, wherein an impedance value of every other impedance element connected is different from an impedance value of the adjustment impedance element. The impedance element is connected in parallel with every other capacitor among the plurality of capacitors,
2. The voltage detection circuit according to claim 1, wherein among the plurality of impedance elements, at least one set of two adjacent impedance elements is connected between the respective voltage measurement lines via a switch. In the case where the number of channels of the voltage detection circuit is larger than the number of the plurality of storage cells,
When the impedance element and the switch are connected to a voltage measurement line that is not connected to a node between the storage cells among the plurality of voltage measurement lines of the voltage detection circuit, the switch is set to be off. The voltage detection circuit according to claim 4. A voltage detection circuit that is connected to each node between a plurality of storage cells connected in series and a plurality of voltage measurement lines, detects a voltage between adjacent voltage measurement lines, and detects a voltage of each storage cell,
A capacitor is connected in parallel with each storage cell between adjacent voltage measurement lines of the plurality of voltage measurement lines,
The voltage detection circuit includes:
Comprising a plurality of discharge paths formed in parallel with the plurality of capacitors,
In the plurality of discharge paths, the impedance value between two adjacent discharge paths is different. A voltage detection circuit that is connected to each node between a plurality of storage cells connected in series and a plurality of voltage measurement lines, detects a voltage between adjacent voltage measurement lines, and detects a voltage of each storage cell,
A capacitor is connected in parallel with each storage cell between adjacent voltage measurement lines of the plurality of voltage measurement lines,
The voltage detection circuit includes:
Comprising a plurality of impedance elements respectively connected in parallel with the plurality of capacitors;
In the plurality of impedance elements, an impedance value between two adjacent impedance elements is different. A plurality of storage cells connected in series;
The voltage detection circuit according to any one of claims 1 to 7, wherein each voltage of the plurality of storage cells is detected.
A power storage system comprising:

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