Battery system

Abstract

To reduce impact of an electromagnetic noise caused by ripple current to reduce an error in voltage detection performed by a control unit.SOLUTION: A battery system comprises: a plurality of battery cells that are stacked on one another; an electric power line between batteries; a voltage detection line; and a control unit that monitors voltage of the plurality of battery cells. The electric power line between batteries connects among a plurality of specific batteries that is a group of specific batteries indicating a single battery cell or a single battery stack. The voltage detection line detects voltage of the plurality of battery cells. The control unit monitors voltage of the plurality of battery cells. The control unit calculates correction voltage of an object battery cell by removing voltage of the electric power line between the batteries from detected voltage of the object battery cell detected using the voltage detection line, and monitors the correction voltage as voltage of the object battery cell.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a battery system. [Background technology]

[0002] Patent Document 1 discloses a flexible printed circuit board (FPC) that includes a laminated wiring board and a shielding film that covers the laminated wiring board and suppresses electromagnetic noise. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-192806 A Summary of the Invention [Problem to be solved by the invention]

[0004] A battery system including multiple battery cells and a control unit that monitors the voltages of the multiple battery cells has the following problem. That is, if a ripple current flowing into the multiple battery cells is large, large electromagnetic noise is generated, and the large electromagnetic noise may be superimposed on a voltage detection line for detecting the voltages of the multiple battery cells. If electromagnetic noise exceeding a reference value is superimposed on the voltage detection line, the error in voltage detection by the control unit will increase.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a battery system that can reduce the effects of electromagnetic noise caused by ripple current and reduce errors in voltage detection by a control unit. [Means for solving the problem]

[0006] A battery system according to the present disclosure includes a plurality of stacked battery cells, an inter-battery power line, a voltage detection line, and a control unit that monitors the voltage of the plurality of battery cells. The inter-battery power line connects between a plurality of specific batteries, which is a collection of specific batteries representing a single battery cell or a single battery stack. The voltage detection line detects the voltage of the plurality of battery cells. The control unit monitors the voltage of the plurality of battery cells. The control unit calculates a corrected voltage of the target battery cell by subtracting the voltage of the inter-battery power line from the detected voltage of the target battery cell detected using the voltage detection line, and monitors the corrected voltage as the voltage of the target battery cell. Effect of the Invention

[0007] According to the present disclosure, it is possible to confirm voltage fluctuations due to electromagnetic noise caused by ripple current from the voltage of the inter-battery power line. Therefore, by subtracting the voltage of the inter-battery power line from the detection voltage of the target battery cell detected using the voltage detection line, it is possible to reduce the influence of electromagnetic noise caused by ripple current and reduce errors in voltage detection by the control unit. [Brief description of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating a schematic configuration of a battery system according to a first embodiment. [Diagram 2] FIG. 4 is a diagram for explaining a method of correcting a cell voltage according to the first embodiment. [Diagram 3] FIG. 13 is a diagram showing a detection channel CH1 of a stack voltage Vs. [Figure 4] FIG. 11 is a diagram illustrating a schematic configuration of a battery system according to a second embodiment. [Diagram 5] 11A to 11C are diagrams showing a specific example of the formation of an FPC according to the second embodiment. [Figure 6] 6 is a diagram for explaining an effect of the battery system according to the second embodiment over the battery system according to the first embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] 1. First embodiment 1-1. Battery system configuration FIG 1 is a diagram illustrating a schematic configuration of a battery system 1 according to a first embodiment. The battery system 1 is mounted on an electric vehicle such as a battery electric vehicle (BEV). The battery system 1 includes a high-voltage battery 10 and a battery ECU (Electronic Control Unit) 20. The battery ECU 20 corresponds to an example of a "control unit" according to the present disclosure.

[0010] When a system main relay (SMR) 3 is ON (energized state), the high-voltage battery 10 supplies power to an electric motor that drives an electric vehicle via a power conversion device such as an inverter. The high-voltage battery 10 includes two battery stacks 11 and 12 as an example of "multiple battery stacks". Each of the battery stacks 11 and 12 is a laminate of multiple battery cells 13, and is configured by connecting the multiple battery cells 13 in series, for example. The high-voltage battery 10 also includes an inter-stack wire harness (inter-stack W / H) 14 that connects between the two adjacent battery stacks 11 and 12.

[0011] The inter-stack W / H 14 corresponds to an example of an "inter-stack power line" according to the present disclosure. A bus bar may be used as the "inter-stack power line" instead of or together with the inter-stack W / H 14. Also, in the first embodiment, each of the battery stacks 11 and 12, i.e., a "single battery stack", corresponds to an example of a "specific battery" according to the present disclosure, and the inter-stack power line corresponds to an example of an "inter-battery power line" according to the present disclosure.

[0012] The battery ECU 20 monitors the voltage of each of the multiple battery cells 13 included in each of the battery stacks 11 and 12. The battery ECU 20 includes, for example, three monitoring ICs (monitoring circuits) 21, 22, and 23, and a microcomputer 24 that transmits control commands to the monitoring ICs 21, 22, and 23. The monitoring ICs 21, 22, and 23 are connected to the microcomputer 24, for example, in a daisy chain. The battery system 1 also includes a flexible printed circuit board (FPC) 30 on which a voltage detection line 31 is formed. The voltage detection line 31 is a collection of multiple voltage detection lines that connect each of the monitoring ICs 21, 22, and 23 to each of the battery cells 13.

[0013] Each of the monitoring ICs 21, 22, and 23 detects the voltage of each battery cell 13 via a voltage detection line 31. The voltage detection line 31 includes a voltage detection line 31a and a voltage detection line 31b. One end of the voltage detection line 31a is connected to the positive terminal of the battery cell 13 located at the end of the battery stack 11 connected to the inter-stack W / H 14. One end of the voltage detection line 31b is connected to the negative terminal of the battery cell 13 located at the end of the battery stack 12 connected to the inter-stack W / H 14. The other ends of the voltage detection lines 31a and 31b are connected to the monitoring IC 22. Therefore, the monitoring IC 22 can also detect the voltage (voltage across both ends) of the inter-stack W / H 14. Each of the monitoring ICs 21, 22, and 23 A / D converts the voltage of each battery cell 13 and the voltage of the inter-stack W / H 14 detected as described above and transmits them to the microcomputer 24.

[0014] The high voltage battery 10 may be configured with three or more battery stacks, and the battery ECU 20 may include two or less, or four or more monitoring ICs.

[0015] 1-2.Cell voltage correction method When a ripple current flows into the battery stacks 11 and 12 of the high-voltage battery 10, a large electromagnetic noise is generated, and the large noise may be superimposed on the pattern in the FPC 30 (i.e., the voltage detection line 31). When electromagnetic noise equal to or greater than a predetermined reference value is superimposed on the voltage detection line 31, an error in voltage detection by the battery ECU 20 (control unit) increases. More specifically, an error between the voltage value monitored by the battery ECU 20 and the actual voltage value increases. In addition, the voltage detection circuit including the monitoring ICs 21, 22, and 23 and the voltage detection line 31 includes a hard filter and a digital filter (not shown) for removing noise. However, these filters cannot attenuate all noise, and the voltage value detected by the monitoring ICs 21, 22, and 23 (detection voltage Vc1 described below) is affected by the above-mentioned electromagnetic noise to a certain extent.

[0016] In view of the above-mentioned problems, in the first embodiment, in order to suppress the above-mentioned voltage detection error, the battery ECU 20 (microcomputer 24) corrects the voltage (cell voltage) of each battery cell 13 in the following manner.

[0017] FIG. 2 is a diagram for explaining a correction method of the cell voltage according to the first embodiment. FIG. 3 is a diagram showing a detection channel CH1 of the stack voltage Vs. Ideally, the cell voltage is detected as a constant voltage value (e.g., 3.5 V) over time as shown in FIG. 2(A). However, the detection value (detection voltage Vc1) of the cell voltage actually acquired by the voltage detection line 31 has the above-mentioned electromagnetic noise (e.g., ±0.01 V) superimposed on the true value (e.g., 3.5 V) as shown in FIG. 2(B). This electromagnetic noise is also superimposed on a pair of voltage detection lines 31a and 31b of the detection channel CH1 of the voltage (stack voltage Vs) of the stack W / H 14 as shown in FIG. 3. This detection channel CH1 spans between the two battery stacks 11 and 12, so it cannot detect the cell voltage, but it can detect the electromagnetic noise. Therefore, by detecting the stack voltage Vs while the SMR 3 is ON (energized state), it is possible to detect voltage fluctuations (for example, ±0.01 V) due to electromagnetic noise (ripple noise) as shown in FIG. 2(C).

[0018] The battery ECU 20 (microcomputer 24) acquires the detected voltage Vc1 of each battery cell 13 at a predetermined control period (e.g., several ms) while the SMR 3 is ON. In the first embodiment, the microcomputer 24 also acquires the stack voltage Vs at the same control period using a pair of voltage detection lines 31a and 31b.

[0019] Then, the microcomputer 24 calculates a correction voltage Vc2 of a "target battery cell," which is a battery cell 13 that is a voltage detection target using the voltage detection line 31, by subtracting the stack voltage Vs from the detected voltage Vc1 of the "target battery cell." The calculation of this correction voltage Vc2 is also performed in the above-mentioned control cycle. The microcomputer 24 then monitors the correction voltage Vc2 as the voltage of the target battery cell. In the first embodiment, the target battery cell here corresponds to each battery cell 13 included in the battery stacks 11 and 12. That is, the calculation and monitoring of the correction voltage Vc2 are performed for each battery cell 13.

[0020] As described above, the voltage fluctuation of electromagnetic noise caused by the ripple current can be confirmed from the stack voltage Vs. Therefore, by dividing the stack voltage Vs from the detected voltage Vc1 of each battery cell 13 detected using the voltage detection line 31 as in the correction method according to the first embodiment, the influence of electromagnetic noise caused by the ripple current can be reduced and the error in voltage detection by the battery ECU 20 can be reduced. That is, the detection accuracy of each cell voltage can be improved. This leads to improved detection accuracy of the block voltage (voltage for a group of a predetermined number of battery cells 13) and the stack voltage (the voltage of each of the battery stacks 11 and 12). Furthermore, according to this correction method, the voltage detection accuracy can be improved without changing or adding hardware.

[0021] 2. Second embodiment In the second embodiment, the bus bar 15 described below corresponds to an example of a "correction power line" according to the present disclosure. However, a wire harness may be used as the correction power line instead of the bus bar 15. Also, in the second embodiment, each of the battery cells 13 included in each of the battery stacks 11 and 12, i.e., a "single battery cell," corresponds to an example of a "specific battery" according to the present disclosure, and the correction power line corresponds to an example of an "inter-battery power line" according to the present disclosure.

[0022] 2-1. Battery system configuration 4 is a diagram illustrating a schematic configuration of a battery system 2 according to embodiment 2. The battery system 2 differs from the battery system 1 according to embodiment 1 in the following respects. That is, the FPC 40 of the battery system 2 additionally includes correction channels CH2_1 and CH2_2 for the detected voltage Vc1 of each battery cell 13 for the battery stacks 11 and 12, respectively.

[0023] Specifically, the FPC 40 is formed with a voltage detection line 41. The voltage detection line 41 includes a pair of voltage detection lines 41c and 41d as a correction channel CH2_1 on the battery stack 11 side. The pair of voltage detection lines 41c and 41d are connected between two adjacent battery cells 13 in the stacking direction D of the battery cells 13 in the battery stack 11 (the vertical direction on the paper surface of FIG. 4). More specifically, one end of the voltage detection line 41c is connected to one positive terminal of the two adjacent battery cells 13. One end of the voltage detection line 41d is connected to the other negative terminal of the two adjacent battery cells 13. The other ends of the voltage detection lines 41c and 41d are connected to the monitoring IC 23. For this reason, the monitoring IC 23 can also detect the voltage between the two adjacent battery cells 13 in the battery stack 11, that is, the correction power line voltage Vx1, which is the voltage across the bus bar 15 (see FIG. 5) corresponding to the "correction power line". The pair of voltage detection lines 41a and 41b included in the voltage detection line 41 are the same as the pair of voltage detection lines 31a and 31b in the first embodiment.

[0024] Broadly speaking, the location where the pair of voltage detection lines 41c and 41d are connected is not particularly limited as long as it is between two adjacent battery cells 13 in the battery stack 11. In addition, FIG. 5 is a diagram showing a specific example of the formation of the FPC 40 according to the second embodiment. The FPC 40 is, for example, composed of an FPC 40_1 on the battery stack 11 side and an FPC 40_2 on the battery stack 12 side. The FPCs 40_1 and 40_2 are disposed on the battery stacks 11 and 12, respectively. FIG. 5 is a diagram looking down on the FPC 40 from above, and the longitudinal direction of the FPCs 40_1 and 40_2 is the same as the stacking direction D (the left-right direction on the paper in FIG. 4). In this example, the battery stacks 11 and 12 are disposed side by side in a direction perpendicular to the stacking direction D (the up-down direction on the paper).

[0025] In the example shown in FIG. 5, a pair of voltage detection lines 41c and 41d are connected between two adjacent battery cells 13 at the center in the stacking direction D. More specifically, one end of the voltage detection line 41c is connected to a connection portion 13c of a positive electrode terminal of one of the two adjacent battery cells 13 at the center. One end of the voltage detection line 41d is connected to a connection portion 13d of a negative electrode terminal of the other of the two battery cells 13. One end of the voltage detection line 41c and one end of the voltage detection line 41d are connected via a bus bar 15 (correction power line). The other ends of the pair of voltage detection lines 41c and 41d are connected to a monitoring IC 23, which is not shown in FIG. 5.

[0026] Similarly to the configuration on the battery stack 11 side, the voltage detection line 41 includes a pair of voltage detection lines 41e and 41f as a correction channel CH2_2 on the battery stack 12 side. The connection locations of the pair of voltage detection lines 41e and 41f are determined based on the same concept as the connection locations of the pair of voltage detection lines 41c and 41d on the battery stack 11 side. In the example shown in FIG. 5, the pair of voltage detection lines 41e and 41f are connected between two adjacent battery cells 13 at the center in the stacking direction D. More specifically, one end of the voltage detection line 41e is connected to a connection portion 13e of one of the positive electrode terminals of the two adjacent battery cells 13 at the center. One end of the voltage detection line 41f is connected to a connection portion 13f of the other negative electrode terminal of the two battery cells 13. One end of the voltage detection line 41e and one end of the voltage detection line 41f are connected via a bus bar 15 (correction power line). The other ends of each of the pair of voltage detection lines 41e and 41f are connected to a monitoring IC 21, which is not shown in Fig. 5. For this reason, the monitoring IC 21 can also detect the voltage between two adjacent battery cells 13 in the battery stack 12, that is, the correction power line voltage Vx2, which is the voltage across the bus bar 15 (see Fig. 5) that corresponds to the "correction power line."

[0027] 2-2.Cell voltage correction method In the second embodiment, in order to suppress the above-mentioned voltage detection error, the battery ECU 20 (microcomputer 24) corrects the voltage (cell voltage) of each battery cell 13 by the following method. That is, the electromagnetic noise described in the first embodiment is also superimposed on the pair of voltage detection lines 41c and 41d of the correction channel CH2_1 according to the second embodiment, and the pair of voltage detection lines 41e and 41f of the correction channel CH2_2. Since the correction channel CH2_1 and CH2_2 are connected between two adjacent battery cells 13, the cell voltage cannot be detected, but the electromagnetic noise can be detected. Therefore, in the second embodiment, the correction power line voltages Vx1 and Vx2 are used instead of the stack voltage Vs.

[0028] Specifically, for the battery stack 11, the microcomputer 24 calculates a correction voltage Vc2' of the target battery cell, which is the battery cell 13 that is the target of voltage detection using the voltage detection line 41, by subtracting the correction power line voltage Vx1 from the detection voltage Vc1 of the "target battery cell". Then, the microcomputer 24 monitors the correction voltage Vc2' as the voltage of the target battery cell. Similarly, for the battery stack 12, the microcomputer 24 calculates a correction voltage Vc2' of the target battery cell by subtracting the correction power line voltage Vx2 from the detection voltage Vc1 of the "target battery cell". Then, the microcomputer 24 monitors the correction voltage Vc2' as the voltage of the target battery cell. Note that, in the second embodiment as well, the calculation and monitoring of the correction voltage Vc2' are performed for each battery cell 13 of each battery stack 11 and 12.

[0029] The correction power line voltages Vx1 and Vx2 also allow confirmation of voltage fluctuations due to electromagnetic noise caused by the ripple current. Therefore, the correction method according to the second embodiment also reduces the influence of electromagnetic noise caused by the ripple current by dividing the correction power line voltage Vx1 or Vx2 from the detected voltage Vc1 of each battery cell 13, thereby making it possible to reduce errors in voltage detection by the battery ECU 20. In other words, the detection accuracy of each cell voltage can be improved.

[0030] 6(A) and 6(B) are diagrams for explaining the effect of the battery system 2 according to the second embodiment on the battery system 1 according to the first embodiment. In FIG. 6(A) and FIG. 6(B), the FPC 30 according to the first embodiment is shown. Specifically, FIG. 6(A) shows a pair of voltage detection lines 31a and 31b of the detection channel CH1 of the voltage (inter-stack voltage Vs) of the inter-stack W / H 14 used in the first embodiment. In addition, FIG. 6(B) also shows two wiring loops L1 and L2, which are examples of wiring loops of the voltage detection line 31 for actually detecting the cell voltage, for comparison with the wiring loop of the detection channel CH1. The wiring loop L1 is for detecting the cell voltage of the battery cell 13 located at one end of the battery stack 12 in the stacking direction D, and the wiring loop L2 is for detecting the cell voltage of the battery cell 13 located at the other end of the battery stack 12 in the stacking direction D.

[0031] Here, the wiring loop of the detection channel CH1 using the inter-stack W / H 14 is formed to pass through the ends of the two battery stacks 11 and 12 as shown in FIG. 6(A), so that the loop area of ​​the wiring is large. In other words, since the wiring loop spans the two battery stacks 11 and 12, the wiring length in the FPC 30 is large. The larger the loop area of ​​the wiring, the more easily the electromagnetic noise described above is superimposed. In contrast, as can be seen from FIG. 6(A) and FIG. 6(B), the loop area of ​​the wiring loops L1 and L2 is smaller than that of the wiring loop of the detection channel CH1. For this reason, according to the second embodiment in which the "correction power line" connecting two adjacent battery cells 13 in the stacking direction D is used as the "inter-battery power line", it is possible to reduce the deviation of the loop area of ​​the wiring loop of the inter-battery power line from the loop area of ​​the wiring loop (e.g., L1 or L2) of the voltage detection line 31 for detecting the actual cell voltage, and thus the correction variation can be reduced. In other words, providing the correction channels CH2_1 and CH2_2 in the battery stacks 11 and 12, respectively, makes it possible to correct the cell voltages by utilizing electromagnetic noise that is close to the electromagnetic noise superimposed on the voltage detection line 31 for detecting the actual cell voltages. Therefore, the correction method of the second embodiment can improve the detection accuracy of each cell voltage compared to the correction method of the first embodiment.

[0032] In addition, in the example shown in FIG. 5, as described above, the correction channels CH2_1 and CH2_2 are provided in the center of the stacking direction D of the battery stacks 11 and 12. As a result, the loop area of ​​the wiring of the correction channels CH2_1 and CH2_2 is the median of the loop area of ​​the wiring loop of each voltage detection line 31 for detecting the actual cell voltage in each battery stack 11 and 12. As a result, the amount of electromagnetic noise superimposed on the wiring of the correction channels CH2_1 and CH2_2 is also the median of the amount of electromagnetic noise of each voltage detection line 31 for detecting the actual cell voltage in each battery stack 11 and 12. In this way, the correction channels CH2_1 and CH2_2 according to the example shown in FIG. 5 can observe the median of the amount of electromagnetic noise in each battery stack 11 and 12, so that it can be said to be suitable for acquiring electromagnetic noise for correcting the detected voltage Vc1 of each battery cell 13 in each battery stack 11 and 12. Therefore, according to the example shown in FIG. 5, the detection accuracy of each cell voltage can be more appropriately improved.

[0033] 3. Correction to further improve cell voltage detection accuracy In order to further improve the detection accuracy of the cell voltages, the calculation of the correction voltage Vc2 may be performed with correction based on either or both of the following two viewpoints.

[0034] 3-1. Correction based on the length of the voltage detection line (FPC wiring length) In the example shown in FIG. 1, the voltage detection lines 31 are formed on the FPC 30. The length (wiring length of the pattern of the FPC 30) of the pair of voltage detection lines 31 in the FPC 30 used for voltage detection of each battery cell 13 (target battery cell) differs depending on the positional relationship between each battery cell 13 and the corresponding monitoring IC 21, 22, or 23. This is similar to the example of the voltage detection line 41 shown in FIG. 4. When the wiring length differs in this way, the phase shift of the detection voltage Vc1 (including the above-mentioned electromagnetic noise) with respect to the voltage of the inter-battery power line (inter-stack voltage Vs or correction power line voltages Vx1, Vx2) differs between the battery cells 13. In other words, the delay time of the waveform of the detection voltage Vc1 with respect to the waveform of the voltage of the inter-battery power line differs between the battery cells 13.

[0035] Therefore, the battery ECU 20 (microcomputer 24) calculates a phase-corrected voltage Vc1_1 by correcting the phase of the detected voltage Vc1 using the pair of voltage detection lines 31 or 41 in accordance with the length (wiring length) of the pair of voltage detection lines 31 or 41 in the FPC 30 or 40 used to detect the voltage of the target battery cell. Then, the microcomputer 24 calculates a corrected voltage Vc2 by subtracting the voltage of the inter-battery power line from the phase-corrected voltage Vc1_1.

[0036] More specifically, the calculation of the phase-corrected voltage Vc1_1 of a certain target battery cell (phase correction) can be performed, for example, as follows. That is, for example, relationship information that defines the relationship between the length (wiring length) of the pair of voltage detection lines 31 or 41 and the correction amount for reducing the phase shift is determined in advance and stored in the memory of the microcomputer 24. The microcomputer 24 calculates the waveform of the detected voltage Vc1 for a predetermined period (a waveform as shown in FIG. 2(B)) from the data of the detected voltage Vc1 acquired for each control cycle. Next, the microcomputer 24 calculates the phase-corrected voltage Vc1_1 in the current control cycle by correcting the phase of the waveform of the detected voltage Vc1 using the wiring length information (for example, a design value) of the target battery cell and the phase correction amount according to the relationship information.

[0037] By using the phase-corrected voltage Vc1_1 in which the phase shift (in other words, the delay time) has been corrected by the above-mentioned method, it is possible to further improve the detection accuracy of the cell voltages.

[0038] 3-2. Correction based on impedance of voltage detection line (FPC pattern) The impedance (pattern resistance) of a pair of voltage detection lines 31 or 41 in the FPC 30 or 40 used to detect the voltage of each battery cell 13 (target battery cell) differs between the battery cells 13 due to differences in wiring length. Due to this difference, the amount of fluctuation in the detection voltage Vc1 caused by superimposed electromagnetic noise differs between the battery cells 13.

[0039] Therefore, the battery ECU 20 (microcomputer 24) calculates a fluctuation-corrected voltage Vc1_2 by correcting the fluctuation (amplitude) of the detected voltage Vc1 using the pair of voltage detection lines 31 or 41 in the FPC 30 or 40 used to detect the voltage of the target battery cell according to the impedance of the pair of voltage detection lines 31 or 41. Then, the microcomputer 24 calculates the correction voltage Vc2 by subtracting the voltage of the inter-battery power line (stack voltage Vs or correction power line voltages Vx1, Vx2) from the fluctuation-corrected voltage Vc1_2.

[0040] More specifically, the calculation of the fluctuation-corrected voltage Vc1_2 of a certain target battery cell (fluctuation amount correction) can be performed, for example, as follows. That is, for example, relationship information that defines the relationship between the impedance of the pair of voltage detection lines 31 or 41 and the correction amount for reducing the difference in the above-mentioned voltage fluctuation amount is stored in the memory of the microcomputer 24. The microcomputer 24 calculates the fluctuation-corrected voltage Vc1_2 by correcting the fluctuation amount of the detected voltage Vc1 using the correction amount of the voltage fluctuation amount according to the impedance information (for example, a design value) of the target battery cell and the above-mentioned relationship information.

[0041] By using the fluctuation-corrected voltage Vc1_2 in which the voltage fluctuation amount has been corrected by the above-mentioned method, it is possible to further improve the detection accuracy of the cell voltages. [Explanation of symbols]

[0042] 1, 2 battery system, 3 SMR, 10 high voltage battery, 11, 12 battery stack, 13 battery cell, 13c to 13f connection, 14 inter-stack wire harness, 15 bus bar, 20 battery ECU, 21, 22, 23 monitoring IC, 24 microcomputer, 30, 40 FPC, 31, 31a, 31b, 41, 41a to 14f voltage detection line

Claims

1. A plurality of stacked battery cells; An inter-battery power line connecting a plurality of specific batteries, which is a group of specific batteries representing a single battery cell or a single battery stack; a voltage detection line for detecting a voltage of the plurality of battery cells; A control unit that monitors the voltages of the plurality of battery cells; Equipped with The control unit is calculating a corrected voltage of the target battery cell by subtracting the voltage of the inter-battery power line from the detected voltage of the target battery cell detected using the voltage detection line; The corrected voltage is monitored as the voltage of the target battery cell. A battery system comprising:

2. the specific batteries are two adjacent battery cells, the inter-battery power line is a correction power line that connects between the two battery cells, The control unit calculates the correction voltage of the target battery cell by subtracting the voltage of the correction power line from the detected voltage of the target battery cell. The battery system according to claim 1 .

3. the specific batteries are two adjacent battery stacks, the inter-battery power line is an inter-stack power line connecting the two battery stacks, The control unit calculates the corrected voltage of the target battery cell by subtracting the voltage of the stack power line from the detected voltage of the target battery cell. The battery system according to claim 1 .

4. The voltage detection line is formed on a flexible printed wiring board, The control unit is correcting a phase of the detected voltage in accordance with a length of a pair of voltage detection lines used to acquire the detected voltage of the target battery cell, and calculating a phase-corrected voltage; The corrected voltage is calculated by subtracting the voltage of the inter-battery power line from the phase-corrected voltage.

4. The battery system according to claim 1, wherein the battery is a battery having a first and a second electrodes.

5. The voltage detection line is formed on a flexible printed wiring board, The control unit is correcting an amount of fluctuation in the detected voltage in accordance with an impedance of a pair of voltage detection lines used to acquire the detected voltage of the target battery cell, thereby calculating a fluctuation-corrected voltage; The correction voltage is calculated by subtracting the voltage of the inter-battery power line from the fluctuation-corrected voltage.

4. The battery system according to claim 1, wherein the battery is a battery having a first and a second electrodes.

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