Management system of power storage device

Abstract

To provide a management system of a power storage device capable of reducing detection errors caused by noise when calculating the voltage of each storage cell included in a power storage device individually.SOLUTION: A system for managing a power storage device with a first cell and a second cell includes a voltage detection circuit. The voltage detection circuit includes: a first detector (detector 201) that detects the voltage of the first cell; and a second detector (detector 202) that detects the first total voltage corresponding to the sum of the voltage of the first cell and the voltage of the second cell. The system is configured to acquire the voltage of the second cell based on the value obtained by subtracting the detection result (voltage V1) by the first detector from the detection result (voltage V2) by the second detector.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a management system for a power storage device. [Background technology]

[0002] Japanese Patent No. 6168813 (Patent Document 1) discloses a technique for detecting the voltage of each of a plurality of battery cells (electricity storage cells). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6168813 Summary of the Invention [Problem to be solved by the invention]

[0004] The technology described in Patent Document 1 improves voltage detection accuracy by providing a filter circuit that removes noise. However, a filter circuit cannot necessarily remove all noise. Furthermore, adding a filter can result in a lack of circuit space and increased costs.

[0005] The present disclosure has been made to solve the above-mentioned problem, and its purpose is to reduce detection errors caused by noise when individually determining the voltage of each storage cell included in a storage device. [Means for solving the problem]

[0006] According to one embodiment of the present disclosure, there is provided a management system for a power storage device as described below.

[0007] The energy storage device management system (hereinafter also simply referred to as "system") is configured to manage an energy storage device including a plurality of energy storage cells. The plurality of energy storage cells include a first cell and a second cell. The system includes a voltage detection circuit. The voltage detection circuit includes a first detector that detects the voltage of the first cell and a second detector that detects a first total voltage that corresponds to the sum of the voltages of the first cell and the second cell. The system is configured to obtain the voltage of the second cell based on a value obtained by subtracting the detection result of the first detector from the detection result of the second detector.

[0008] The detection results from the first detector and the second detector may contain errors due to electromagnetic noise. In this regard, according to the above configuration, the detection result from the first detector is subtracted from the detection result from the second detector, thereby canceling out the effects of electromagnetic noise and reducing detection errors. Therefore, the energy storage device management system can reduce detection errors due to noise when individually determining the voltage of each energy storage cell included in the energy storage device. [Effects of the Invention]

[0009] According to the present disclosure, when the voltage of each storage cell included in a power storage device is determined individually, it is possible to reduce detection errors caused by noise. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram illustrating a configuration of a management system for a power storage device according to an embodiment of the present disclosure. [Figure 2] 2 is a diagram showing an example of the configuration of a cell included in the power storage device according to the present embodiment. FIG. [Figure 3] FIG. 1 is a diagram illustrating a problem related to a management system for a power storage device. [Figure 4] 10A and 10B are diagrams for explaining the actions and effects achieved by the power storage device management system according to the present embodiment. [Figure 5] FIG. 10 is a diagram showing a first modified example of the management system for the power storage device according to the present embodiment. [Figure 6] FIG. 10 is a diagram showing a second modified example of the management system for the power storage device according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, identical or corresponding parts are designated by the same reference numerals, and their description will not be repeated. In each drawing, the directions of three mutually orthogonal axes (X-axis, Y-axis, and Z-axis) are indicated by adding a "+" in the direction indicated by the arrow and a "-" in the opposite direction.

[0012] Fig. 1 is a diagram showing the configuration of a vehicle equipped with a power storage device management system according to this embodiment. Referring to Fig. 1, a vehicle 1000 includes an inlet 11, an SPU (Smart Power Unit) 12, a charging relay 13, a PCU (Power Control Unit) 21, an MG (Motor Generator) 22, a battery 100, a temperature regulator 310, an SMR (System Main Relay) 320, and an ECU (Electronic Control Unit) 500. The ECU 500 incorporates a computer including one or more processors and one or more storage devices. The ECU 500 corresponds to an example of an "information processing device" according to the present disclosure.

[0013] The vehicle 1000 is configured to be able to travel using electric power output from the battery 100. The vehicle 1000 is, for example, an electric vehicle (BEV) that does not have an internal combustion engine. However, the vehicle 1000 is not limited to this, and may be a plug-in hybrid electric vehicle (PHEV) that has an internal combustion engine, or another type of electric vehicle (xEV). The SMR 320 is a relay located between the battery 100 and the PCU 21. The MG 22 functions as a drive motor and rotates the drive wheels of the vehicle 1000. The PCU 21 drives the MG 22 using electric power supplied from the battery 100. The PCU 21 includes, for example, an inverter. The MG 22 converts electric power into torque, which is transmitted to the drive wheels. Furthermore, the MG 22 performs regenerative power generation, for example, when the vehicle 1000 decelerates, to charge the battery 100.

[0014] The battery 100 is provided with a temperature adjustment device 310 that adjusts the temperature of the battery 100, and a BMS (Battery Management System) 200 that monitors the state of the battery 100. The temperature adjustment device 310 may include an electric heater and / or a blower, or may include a heat medium circuit in which a heat medium (e.g., a refrigerant) circulates by driving a pump.

[0015] The BMS 200 is configured to detect the voltage of the battery 100 and output the detection result to the ECU 500. In this embodiment, only the voltage measurement function of the BMS 200 will be described. However, the BMS 200 may further have a function (e.g., a circuit) for measuring at least one of the current and temperature of the battery 100. The ECU 500 uses the information about the battery 100 acquired from the BMS 200 to control various devices (including the SPU 12, the PCU 21, the temperature regulator 310, and the SMR 320) mounted on the vehicle 1000.

[0016] The SPU 12 is provided on the charging line CHL and functions as an on-board charger (charging circuit). The SPU 12 may also function as an ESU (Electric Supply Unit). The charging relay 13 switches between connection and disconnection of the charging line CHL. When the tip (connector) of a charging cable connected to an EVSE (Electric Vehicle Supply Equipment, not shown) is connected to the inlet 11 (plug-in), the vehicle 1000 is electrically connected to the EVSE, enabling external charging (charging of the battery 100 using power from outside the vehicle). One end of the charging line CHL is connected between the SMR 320 and the PCU 21, and the other end is connected to the inlet 11. However, this is not a limitation, and one end of the charging line CHL may be connected between the battery 100 and the SMR 320. The vehicle 1000 may be configured to perform wireless charging of the battery 100 instead of or in addition to the plug-in charging.

[0017] As shown in FIG. 1 , battery 100 includes a plurality of storage cells (hereinafter simply referred to as “cells”), each functioning as a secondary battery. Examples of cells include secondary batteries such as lithium-ion batteries, nickel-metal hydride batteries, and sodium-ion batteries. Examples of lithium-ion batteries include LFP batteries that use lithium iron phosphate as the positive electrode active material, and ternary batteries that use NMC (nickel-manganese-cobalt) as the positive electrode active material. The type of secondary battery may be a liquid secondary battery or an all-solid-state secondary battery. Battery 100 may include only storage cells of the same type (e.g., only ternary batteries) or may include storage cells of different types (e.g., LFP batteries and ternary batteries). Battery 100 corresponds to an example of an “energy storage device” according to the present disclosure.

[0018] Fig. 2 is a diagram showing an example of the cell configuration. Referring to Fig. 2, cell 10 includes electrodes 110 and 120, a gas release valve 130, a sealing portion 140, and a case 150. Electrode 110 includes an electrode portion 111 and a connecting pin 112, and functions as a positive electrode terminal. Electrode 120 includes an electrode portion 121 and a connecting pin 122, and functions as a negative electrode terminal.

[0019] The case 150 has an electrode surface F1 on which the electrodes 110 and 120 are provided, and a bottom surface F2 opposite the electrode surface F1. The case 150 includes a main body 151 and a lid 152. The main body 151 is a cylindrical housing with a bottom and an opening on the electrode surface F1 side. The main body 151 is a housing made of, for example, metal. The lid 152 is a plate-like member having an outer shape corresponding to the opening of the main body 151 and closes the opening of the main body 151. The lid 152 is a cover member made of, for example, an insulating material such as resin. In the example shown in FIG. 2, the outer surface of the lid 152 (the surface opposite the main body 151) is the electrode surface F1 of the case 150. The bottom surface of the main body 151 is the bottom surface F2 of the case 150. The lid 152 may be made of metal. An insulating seal material (for example, a ceramic part) may be provided around at least one of the electrodes 110, 120 in the lid portion 152 to insulate the electrodes from each other.

[0020] As shown in the exploded view of FIG. 2, the case 150 houses an insulating film 160 and an electrode assembly 170. The electrode assembly 170 is, for example, a wound body, and has a structure in which a positive electrode sheet and a negative electrode sheet are wound with a separator interposed therebetween. Each of the positive electrode sheet and the negative electrode sheet includes an electrode foil and an active material layer. The insulating film 160 is provided between the electrode assembly 170 and the main body 151, and electrically insulates them from each other. Note that an electrode assembly formed of two or more wound bodies may be used instead of the electrode assembly 170. Also, instead of a wound body, an electrode assembly having a laminated structure (for example, a laminate in which a positive electrode sheet and a negative electrode sheet are stacked with a separator interposed therebetween) may be used.

[0021] The electrode assembly 170 is provided with a positive electrode tab 171 and a negative electrode tab 172. The positive electrode tab 171 and the negative electrode tab 172 are connected (for example, by welding) to current collector plates 181 and 182, respectively. Current from each positive electrode sheet in the electrode assembly 170 is collected to the current collector plate 181 via the positive electrode tab 171. A connecting pin 112 joined to the electrode unit 111 passes through a hole (not shown) penetrating the lid unit 152 and is connected to the current collector plate 181. The connecting pin 112 is conductive and electrically connects the current collector plate 181 and the electrode unit 111. Current from each negative electrode sheet in the electrode assembly 170 is collected to the current collector plate 182 via the negative electrode tab 172. A connecting pin 122 joined to the electrode unit 121 passes through a hole (not shown) penetrating the lid unit 152 and is connected to the current collector plate 182. The connecting pin 122 is conductive and electrically connects the current collector plate 182 and the electrode portion 121 .

[0022] The case 150 further contains an electrolyte and is sealed. The gas release valve 130 opens when the pressure inside the case 150 exceeds a predetermined level, thereby preventing an excessive increase in internal pressure. The sealing portion 140 is the portion where the liquid inlet is sealed. In manufacturing the cell 10, after the electrolyte is injected into the case through the liquid inlet, the liquid inlet is sealed with a sealing member.

[0023] Referring again to FIG. 1, battery 100 includes n cells (cell 1, cell 2, cell 3, cell 4, . . . , cell n-1, and cell n). n may be equal to or greater than 10 and equal to or less than 50. However, the number of storage cells is arbitrary. n may be equal to or greater than 2 and less than 10, or may be greater than 50. Cells 1 to n are arranged in the X direction in the order of cell 1, cell 2, cell 3, cell 4, . . . , cell n-1, and cell n from the -X side. Each of cells 1 to n has, for example, a rectangular parallelepiped shape that is elongated in the Y direction. As each cell (cell 1 to n) included in battery 100, cell 10 (storage cell) shown in FIG. 2 is used, for example. However, in battery 100, the arrangement of the positive and negative electrodes is reversed between odd-numbered cells from the -X side (hereinafter referred to as "odd-numbered cells") and even-numbered cells from the -X side (hereinafter referred to as "even-numbered cells"). That is, the odd-numbered cells (cell 1, cell 3, . . . and cell n-1) and the even-numbered cells (cell 2, cell 4, . . . and cell n) have the same configuration, but are arranged such that one is rotated 180° relative to the other around the Z axis as the rotation axis. For example, each storage cell belonging to the odd-numbered cells has the configuration shown in FIG. 2 and is arranged so that the electrode surface F1 faces the +Z side, the bottom surface F2 faces the -Z side, the positive electrode side surface faces the -Y side, and the negative electrode side surface faces the +Y side. Also, each storage cell belonging to the even-numbered cells has the configuration shown in FIG. 2 and is arranged so that the electrode surface F1 faces the +Z side, the bottom surface F2 faces the -Z side, the positive electrode side surface faces the +Y side, and the negative electrode side surface faces the -Y side. The battery 100 may be mounted on the vehicle 1000 with the -Z side surface (bottom surface F2) facing downward (in the direction of gravity).

[0024] Cell 1 has a positive terminal (electrode 110) at its -Y end and a negative terminal (electrode 120) at its +Y end. Cell 2 has a negative terminal (electrode 120) at its -Y end and a positive terminal (electrode 110) at its +Y end. Cell 3 has a positive terminal (electrode 110) at its -Y end and a negative terminal (electrode 120) at its +Y end. Cell 4 has a negative terminal (electrode 120) at its -Y end and a positive terminal (electrode 110) at its +Y end. Terminal E1 shown in FIG. 1 is the positive terminal of battery 100 and corresponds to the positive terminal (first terminal) of cell 1 located at the -X end of battery 100. The negative terminal (second terminal) of cell 1 and the positive terminal (fourth terminal) of cell 2 are electrically connected via bus bar L1 (first conductive member). The negative electrode terminal (third terminal) of cell 2 and the positive electrode terminal (fifth terminal) of cell 3 are electrically connected via a busbar L2 (second conductive member). The negative electrode terminal (sixth terminal) of cell 3 and the positive electrode terminal of cell 4 are electrically connected via a busbar L3 (third conductive member). In this way, the negative electrode terminal of the mth odd-numbered cell from the -X side is electrically connected to the positive electrode terminal of the even-numbered cell located on the +X side thereof via a busbar Lm (m is an odd number). In addition, the negative electrode terminal of the mth even-numbered cell from the -X side is electrically connected to the positive electrode terminal of the odd-numbered cell located on the +X side thereof via a busbar Lm (m is an even number). Each busbar is made of a conductive material (e.g., metal). The busbars and terminals may be connected by welding or fastening. Cells 1 to n are connected in series as described above. The electrically connected cells 1 to n function as a single battery pack.

[0025] The BMS 200 further includes a voltage detection circuit including detectors 201 to 204. Detector 201 (first detector) detects the potential difference (voltage V1) between the positive terminal of cell 1 and busbar L1. Detector 202 (second detector) detects the potential difference (voltage V2) between the positive terminal of cell 1 and busbar L2. Detector 203 (third detector) detects the potential difference (voltage V3) between busbar L1 and busbar L3. Detector 204 (fourth detector) detects the potential difference (voltage V4) between busbar L2 and busbar L4. Each busbar has the same potential as the two terminals connected to both ends. For example, busbar L3 has the same potential as the negative terminal of cell 3 and the positive terminal of cell 4.

[0026] Fig. 3 is a diagram for explaining a problem related to a management system for a power storage device. As a method for individually determining the voltage of each power storage cell included in a power storage device, it is possible to provide a voltage sensor between the terminals of each power storage cell to detect the voltage of the power storage cell. The system according to the reference example shown in Fig. 3 is a management system for a power storage device that employs such a method.

[0027] 3, the system according to the reference example includes a BMS 200X and an ECU 500X. The BMS 200X includes a voltage detection circuit including detectors 201X to 204X. The detector 201X detects the voltage (V cell 1). Detector 202X detects the voltage of cell 2 (V cell 2). Detector 203X detects the voltage of cell 3 (V cell 3). Detector 204X detects the voltage of cell 4 (V cell The detection results (detected voltage values) by the detectors 201X, 202X, 203X, and 204X are input to the ECU 500X. cell 1. V cell 2. V cell 3. V cell 4) are recognized as the voltages of cell 1, cell 2, cell 3, and cell 4, respectively.

[0028] In the battery 100, current flows as shown in FIG. 3. Specifically, current flows in the Y direction in each cell. However, the current flows in opposite directions in odd-numbered and even-numbered cells. The current flowing through each cell generates electromagnetic noise (for example, changes in magnetic flux passing through the loop of the voltage detection circuit). As a result, the detection results of each of the detectors 201X to 204X contain detection errors caused by electromagnetic noise. For this reason, it is difficult to detect individual cell voltages with high accuracy in the system according to the reference example shown in FIG. 3. While it is possible to suppress changes in the magnetic field by adding a magnetic shielding plate to the system, adding a magnetic shielding plate would increase the size and weight of the system or increase costs.

[0029] FIG. 4 is a diagram for explaining the actions and effects achieved by the system shown in FIG. 1. The management system for an electricity storage device according to this embodiment has the configuration shown in FIG. 4. Although FIG. 4 shows an example in which n is an even number, n may be an odd number. Terminal E2 shown in FIG. 4 is the negative terminal of battery 100, and corresponds to the negative terminal of cell n (the nth cell from the −X side) located at the end of the +X side of battery 100. Cells 1 to n included in battery 100 are connected in series by n−1 bus bars L1 to Ln−1.

[0030] The voltage detection circuit of the BMS 200 includes a detector 201, a detector 202, a detector 203, a detector 204, ..., a detector 20n-1, and a detector 20n. Each detector functions as a voltage sensor. The detector 201 detects the voltage of one storage cell, and the other detectors detect the sum (total voltage) of the voltages of two storage cells. Specifically, the detector 201 detects the voltage of cell 1 (V cell Detector 202 detects a voltage V1 corresponding to the sum of the voltages of cell 1 and cell 2 (V cell 1+V cell Detector 203 detects a voltage V2 (first sum voltage) corresponding to the sum of the voltages of cell 2 and cell 3 (V cell 2+V cellDetector 204 detects a voltage V3 (second sum voltage) corresponding to the sum of the voltages of cell 3 and cell 4 (V cell 3+V cell Detector 20n-1 detects a voltage V4 (third total voltage) corresponding to the sum of the voltages of cells n-2 and n-1 (V cell (n-2)+V cell The detector 20n detects a voltage Vn-1 corresponding to the sum of the voltages of the cells n-1 and n (V cell (n-1)+V cell The detection results (detected voltages V1 to Vn) by the respective detectors are input to ECU 500.

[0031] The ECU 500 obtains the voltage of each of the cells 1 to n using the voltages V1 to Vn. Specifically, the ECU 500 obtains the voltage of cell 2 (V cell 2) from the detection result (voltage V3) of the detector 203. cell 2), the voltage of cell 3 (V cell The ECU 500 obtains the voltage (V 3 ) of cell 3 from the detection result (voltage V 4 ) of the detector 204. cell 3), the voltage of cell 4 (V cell 4). In this way, the ECU 500 obtains the voltage of the cell on the +X side using the total voltage of two cells adjacent in the X direction and the voltage of the cell on the -X side. That is, the ECU 500 obtains the voltage of cell n-1 (V cell (n-1)) to obtain the voltage of cell n (V cell In this way, the individual cell voltages are calculated starting from the cell located on the -X side.

[0032] According to the system shown in FIG. 4, the effect of electromagnetic noise is canceled by subtracting the detection result of one detector from the detection result of another detector, thereby reducing detection errors. This makes it possible to reduce detection errors caused by noise when individually determining the voltage of each storage cell included in the energy storage device. According to the energy storage device management system of this embodiment, it becomes possible to acquire the voltage of each of cells 1 to n with high accuracy. Furthermore, by arranging the two terminals connected to the detectors at the ends of the same side (+Y side or -Y side) of the storage cell, the loop area formed by the detector together with those terminals is smaller than in the reference example (FIG. 3). This reduces the effect of electromagnetic noise.

[0033] FIG. 5 is a diagram showing a first modified example of the management system for the power storage device shown in FIG. 4. The system shown in FIG. 5 includes an ECU 500A instead of the ECU 500 (FIG. 4). The ECU 500A is configured to perform at least one of calculations B and C to obtain an average cell voltage, in addition to calculation A (a calculation executed by the ECU 500 shown in FIG. 4) for obtaining the individual cell voltages (the voltages of the cells 1 to n). When an individual cell voltage is requested (for example, when control using the individual cell voltage is executed), the ECU 500A obtains the individual cell voltage by calculation A. However, the ECU 500A accepts not only requests for the individual cell voltages but also requests for the average cell voltage. When an average cell voltage is requested (for example, when control using the average cell voltage is executed), the ECU 500A executes at least one of calculations B and C.

[0034] In Calculation B, only half of the voltages V1 to Vn (hereinafter referred to as "odd cell voltages") are used to calculate the average cell voltage. The odd cell voltages include the detected value of cell 1's voltage (voltage V1) and the detected value of the sum (total voltage) of two cell voltages for adjacent cell combinations (more specifically, the combination of an even cell and an odd cell located on the +X side of that even cell). The odd cell voltages include the detected values ​​for each cell combination (voltages V3, V5, . . . , Vn-3, Vn-1) for the total voltage. In Calculation B, the average cell voltage of cells 1 to n is calculated by dividing the sum of the odd cell voltages by n.

[0035] In calculation C, the average cell voltage is calculated using only the half of the voltages V1 to Vn that are not odd cell voltages (hereinafter referred to as the "even cell voltages"). The even cell voltages include the detected values ​​(voltages V2, V4, . . . , Vn-2, Vn) for each cell combination, which are the sum (total voltage) of two cell voltages for a combination of adjacent cells (more specifically, the combination of an odd cell and an even cell located on the +X side of that odd cell). In calculation C, the average cell voltage of cells 1 to n is calculated by dividing the sum of the even cell voltages by n.

[0036] The ECU 500 may execute both Calculation B and Calculation C, and use at least one of the average cell voltage calculated in Calculation B and the average cell voltage calculated in Calculation C to determine the final average cell voltage. The ECU 500 may also determine whether or not there is a system abnormality based on whether the degree of deviation between the average cell voltage calculated in Calculation B and the average cell voltage calculated in Calculation C exceeds a reference level. If the degree of deviation is smaller than the reference level, the ECU 500 may determine the average cell voltage to be either the value calculated in Calculation B or the value calculated in Calculation C, or the average value of these values. The ECU 500 may also execute only one of Calculations B and C. By executing either Calculation B or C, the ECU 500 can calculate the average cell voltage of cells 1 to n.

[0037] In the system according to the above embodiment or the first modification, the ECU 500 or 500A (information processing device) performs a conversion process (subtraction) from the detection results (voltages V1 to Vn) of each detector to individual cell voltages (the voltages of cells 1 to n). However, this is not limiting, and the voltage detection circuit may include a circuit for such a conversion process and be configured to output the individual cell voltages to the information processing device.

[0038] Fig. 6 is a diagram showing a second modified example of the management system for the power storage device shown in Fig. 4. The system shown in Fig. 6 includes a BMS 200A instead of the BMS 200 (Fig. 4). The voltage detection circuit of the BMS 200A further includes n-1 subtraction circuits (subtraction circuit 211, subtraction circuit 212, subtraction circuit 213, ..., subtraction circuit 21n-2, and subtraction circuit 21n-1) in addition to n detectors (detector 201, detector 202, detector 203, detector 204, ..., detector 20n-1, and detector 20n).

[0039] The voltage of cell 1 (voltage V1) detected by detector 201 and the total voltage (voltage V2) detected by detector 202 are input to subtraction circuit 211 (first subtraction circuit). Then, subtraction circuit 211 calculates a value (V cell 2) is output to the subtraction circuit 212 (second subtraction circuit). cell 2) and the total voltage (voltage V3) detected by the detector 203. The subtraction circuit 212 then subtracts V from V cell The value obtained by subtracting 2 (V cell The subtraction circuit 213 (third subtraction circuit) outputs the output value (V cell 3) and the total voltage (voltage V4) detected by the detector 204. Then, the subtraction circuit 213 subtracts V cell The value obtained by subtracting 3 (V cell The subtraction circuit 21n-1 outputs the output value (V cell (n-1)) and the total voltage (voltage Vn) detected by the detector 20n are input to the subtraction circuit 21n-1. Then, the subtraction circuit 21n-1 subtracts Vn from V cellThe value obtained by subtracting (n-1) (V cell (n)).

[0040] The detected value (V cell 1) and the voltages (V cell 2. V cell 3. V cell 4, , V cell (n-1), V cell (n)) is output to an information processing device (for example, an on-board control device such as ECU 500 shown in FIG. 1). According to the system of the second modification, the calculation load on the information processing device is reduced when the voltage of each storage cell included in the power storage device is individually determined.

[0041] In the above-described embodiment or each modification, multiple signal lines (lines transmitting voltage detection values) connecting a voltage detection circuit (e.g., BMS) and an information processing device (e.g., ECU) may run in parallel. Then, the voltage detection circuit and the information processing device may be connected via, for example, a connector, so that the multiple signal lines on the voltage detection circuit side are connected to the corresponding multiple signal lines on the information processing device side.

[0042] It is not essential that all of the storage cells included in the energy storage device are connected in series. At least some of the storage cells included in the energy storage device may be connected in parallel. The configuration of the storage cells is not limited to the configuration shown in Fig. 2. The shape, dimensions, components, etc. of the storage cells shown in Fig. 2 may be changed as appropriate.

[0043] 1, battery 100 is disposed on the floor of vehicle 1000, but the power storage device may also be installed under the floor of the vehicle. The vehicle is not limited to a passenger car, but may also be a bus, truck, work vehicle (tractor, forklift, etc.), or automated guided vehicle (AGV). The power storage device may be used for any purpose, and may be stationary.

[0044] The various features of the above-described system (the features described in the embodiments and modifications) may be implemented in any combination. The power storage device may be applied to devices other than vehicles.

[0045] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the description of the above embodiments, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0046] 10 cells, 100 batteries, 110,120 electrodes, 200,200A BMS, 201~20n detectors, 211~21n-1 subtraction circuits, 500,500A ECU, 1000 vehicles, E1,E2 terminals, L1~Ln-1 busbars.

Claims

1. A system for managing a power storage device including a plurality of power storage cells, the plurality of storage cells include a first cell and a second cell; The system includes a voltage detection circuit; The voltage detection circuit a first detector that detects a voltage of the first cell; a second detector for detecting a first total voltage corresponding to the sum of the voltage of the first cell and the voltage of the second cell; Including, A management system for a power storage device, wherein the system is configured to acquire the voltage of the second cell based on a value obtained by subtracting the detection result by the first detector from the detection result by the second detector.

2. the plurality of storage cells further includes a third cell; the voltage detection circuit further includes a third detector that detects a second total voltage corresponding to the sum of the voltage of the second cell and the voltage of the third cell; 2. The energy storage device management system according to claim 1, wherein the system is configured to obtain the voltages of the second cell and the third cell using the voltage of the first cell, the first total voltage, and the second total voltage.

3. the plurality of power storage cells are arranged in a first direction in the order of the first cell, the second cell, and the third cell, the first cell has a first terminal on one side in a second direction perpendicular to the first direction and a second terminal on the other side in the second direction; the second cell has a third terminal on one side in the second direction and a fourth terminal on the other side in the second direction; the third cell has a fifth terminal on one side in the second direction and a sixth terminal on the other side in the second direction; The power storage device is a first conductive member electrically connecting the second terminal and the fourth terminal; a second conductive member electrically connecting the third terminal and the fifth terminal; further comprising the first detector is configured to detect a potential difference between the first terminal and the first conductive member as a voltage of the first cell; the second detector is configured to detect a potential difference between the first terminal and the second conductive member as the first total voltage; The power storage device management system according to claim 2 , wherein the third detector is configured to detect, as the second total voltage, a potential difference between the first conductive member and the sixth terminal.

4. The system further includes an information processing device including a processor; The information processing device includes: obtaining the voltage of the second cell by subtracting the voltage of the first cell from the first total voltage; The power storage device management system according to claim 2 or 3, configured to obtain the voltage of the third cell by subtracting the voltage of the second cell from the second total voltage.

5. The voltage detection circuit a first subtraction circuit that receives the voltage of the first cell detected by the first detector and the first total voltage, and outputs a value obtained by subtracting the voltage of the first cell from the first total voltage; a second subtraction circuit that receives the output value of the first subtraction circuit and the second total voltage and outputs a value obtained by subtracting the output value of the first subtraction circuit from the second total voltage; The power storage device management system according to claim 2 or 3, further comprising:

Images