Voltage detection circuit, abnormality detection device, and battery system

Abstract

The present invention provides a voltage detection circuit, an abnormality detection device, and a battery system. The voltage detection circuit comprises: a first terminal for connecting to the other end of a first voltage detection line connected to a first electrode at one end via a first resistor, the first electrode being either the anode or the cathode of a first battery; a second terminal for connecting to the other end of the first voltage detection line without passing through the first resistor; a first current generating circuit connected to the first terminal; and a voltage detector for detecting the voltage at the first terminal and the voltage at the second terminal. The voltage detector comprises at least one first AD converter connected to the first terminal and at least one second AD converter connected to the second terminal, wherein voltage detection by the first AD converter and voltage detection by the second AD converter are performed substantially simultaneously, the first AD converter detecting and outputting the voltage at the first terminal, and the second AD converter detecting and outputting the voltage at the second terminal.

Description

[0001] This application is a divisional application of the invention patent application with application date of September 15, 2016, application number 201680052048.4, and invention name “Voltage detection circuit, abnormality detection device, and battery system”. Technical Field

[0002] The present invention relates to a voltage detection circuit for detecting the voltage of a battery, an abnormality detection device, and a battery system. Background Art

[0003] Conventionally, a battery system is disclosed. The battery system includes a battery and a voltage detection circuit connected to the battery and detecting the voltage of the battery.

[0004] In such a battery system, if a connection abnormality such as a disconnection occurs in a voltage detection line connecting the battery and the voltage detection circuit, the voltage detection circuit cannot accurately detect the battery voltage.

[0005] Therefore, a method of detecting a connection abnormality in a voltage detection line has been conventionally proposed.

[0006] For example, the technology disclosed in Patent Document 1 detects whether a connection abnormality has occurred in a voltage detection line by comparing a battery voltage detected before discharge of a capacitor constituting a filter circuit connected to the voltage detection line with a battery voltage detected after discharge of the capacitor.

[0007] (Prior art literature)

[0008] (Patent Document)

[0009] Patent Document 1 Japanese Patent Application Laid-Open No. 2014-219277

[0010] However, the technology described in Patent Document 1 mentioned above causes a time difference between the timing of detecting the battery voltage before the capacitor is discharged and the timing of detecting the battery voltage after the capacitor is discharged. Therefore, if the battery voltage fluctuates between the timing of detecting the battery voltage before and after the capacitor is discharged, it may cause errors in detecting whether there is a connection abnormality in the voltage detection line. Summary of the Invention

[0011] Therefore, in view of the above-mentioned problems, an object of the present invention is to provide a voltage detection circuit, an abnormality detection device, and a battery system that can reduce the possibility of erroneous determination of whether a connection abnormality has occurred in a voltage detection line compared to conventional methods.

[0012] A voltage detection circuit according to one embodiment of the present invention comprises: a first terminal for connecting to the other end of a first voltage detection line connected to a first electrode at one end via a first resistor, the first electrode being one of the anode and the cathode of a first battery; a second terminal for connecting to the other end of the first voltage detection line without passing through the first resistor; a first current generating circuit connected to the first terminal; and a voltage detector for detecting the voltage of the first terminal and the voltage of the second terminal, the voltage detector having at least one first AD converter connected to the first terminal and at least one second AD converter connected to the second terminal, and the voltage detection performed by the first AD converter and the voltage detection performed by the second AD converter are performed approximately simultaneously, the first AD converter detects the voltage of the first terminal and outputs the detected voltage of the first terminal, and the second AD converter detects the voltage of the second terminal and outputs the detected voltage of the second terminal.

[0013] An abnormality detection device involved in one form of the present invention comprises: the above-mentioned voltage detection circuit; the first resistor; a fifth terminal connected to the other end of the first voltage detection line; a first connection path connecting the first terminal and the fifth terminal via the first resistor; a second connection path connecting the second terminal and the fifth terminal without passing through the first resistor; and an abnormality judgment circuit that detects a connection abnormality of the first voltage detection line based on the voltage of the first terminal and the voltage of the second terminal.

[0014] A battery system according to one embodiment of the present invention comprises: the above-mentioned abnormality detection device; the first battery; and the first voltage detection line, wherein one end of the first voltage detection line is connected to the anode or cathode of the first battery, and the other end of the first voltage detection line is connected to the fifth terminal.

[0015] With the voltage detection circuit, abnormality detection device, and battery system described above, when a connection abnormality occurs in the first voltage detection line, since the other end of the first voltage detection line is not connected to the first battery, no voltage difference occurs between the voltage at the first terminal and the voltage at the second terminal. In contrast, when the first voltage detection line does not experience a connection abnormality, since the other end of the first voltage detection line is connected to the first battery, the current generated by the first current generation circuit flows into the first resistor, generating a voltage that creates a voltage difference between the voltage at the first terminal and the voltage at the second terminal. Furthermore, the voltage detector, abnormality detection device, and battery system described above detect the voltage at the first terminal and the voltage at the second terminal.

[0016] To this end, by detecting the difference in the above-mentioned voltages through the above-mentioned voltage detection circuit, abnormality detection device, and battery system, it is possible to determine whether a connection abnormality has occurred in the first voltage detection line. This eliminates the need to make a judgment based on multiple voltage detections performed at different timings as in the past.

[0017] Therefore, by utilizing the voltage detection circuit, the abnormality detection device, and the battery system, the possibility of erroneous determination of whether or not a connection abnormality has occurred in the voltage detection line can be reduced compared to conventional methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a block diagram showing the configuration of the battery system in the first embodiment.

[0019] Figure 2 This is a flowchart of the first abnormality detection process.

[0020] Figure 3A This is a schematic diagram showing the transition of voltage in the first voltage abnormality detection process.

[0021] Figure 3B This is a schematic diagram showing the transition of voltage in the first voltage abnormality detection process.

[0022] Figure 4A This is a schematic diagram showing the transition of voltage in the first voltage abnormality detection process.

[0023] Figure 4B 1 is a diagram showing a voltage transition pattern in the first voltage abnormality detection process.

[0024] Figure 5 This is a block diagram showing the configuration of a battery system in the second embodiment.

[0025] Figure 6 This is a flowchart of the second abnormality detection process.

[0026] Figure 7 This is a flowchart of the third abnormality detection process.

[0027] Figure 8A It is a schematic diagram showing the transition of voltage in the third abnormality detection process.

[0028] Figure 8B It is a schematic diagram showing the transition of voltage in the third abnormality detection process.

[0029] Figure 9 This is a block diagram showing the configuration of a battery system in a third embodiment.

[0030] Figure 10 This is a flowchart of the fourth abnormality detection process.

[0031] Figure 11 This is a block diagram showing the configuration of a battery system in a fourth embodiment.

[0032] Figure 12 This is a flowchart of the fifth abnormality detection process.

[0033] Figure 13 This is a block diagram showing the configuration of a battery system in the fifth embodiment.

[0034] Figure 14 This is a block diagram showing the configuration of a battery system in a sixth embodiment.

[0035] Figure 15 This is a flowchart of the sixth abnormality detection process.

[0036] Figure 16A It is a schematic diagram showing the transition of voltage in the sixth abnormality detection process.

[0037] Figure 16B It is a schematic diagram showing the transition of voltage in the sixth abnormality detection process.

[0038] Figure 17A This is one of the schematic diagrams showing an example of a primary monitoring system and a secondary monitoring system.

[0039] Figure 17B This is a second schematic diagram showing an example of the main monitoring system and the auxiliary monitoring system.

[0040] Figure 17C This is a third schematic diagram showing an example of the main monitoring system and the auxiliary monitoring system.

[0041] Figure 18A This is a fourth schematic diagram showing an example of the main monitoring system and the auxiliary monitoring system.

[0042] Figure 18B This is a fifth schematic diagram showing an example of the main monitoring system and the auxiliary monitoring system.

[0043] Figure 18C This is a sixth schematic diagram showing an example of the main monitoring system and the auxiliary monitoring system.

[0044] Figure 19 This is a schematic diagram showing an example of an abnormality determination circuit.

[0045] Figure 20A This is a diagram showing the configuration of a power storage module management system according to the seventh embodiment.

[0046] Figure 20B This is a diagram showing the configuration of a power storage module management system according to the seventh embodiment.

[0047] Figure 20C This is a diagram showing the configuration of a power storage module management system according to the seventh embodiment.

[0048] Figure 21A This is an example of a circuit diagram illustrating a disconnection detection method.

[0049] Figure 21B The terminal voltage values ​​involved when the wire is not broken and when the wire is broken are shown.

[0050] Explanation of symbols

[0051] 1, 2, 3, 4, 5, 6 battery systems

[0052] 10 battery pack

[0053] 20 Voltage detection line group

[0054] 21 First voltage detection line

[0055] 22 Second voltage detection line

[0056] 30, 530, 930, 1130, 1330, 1430 anomaly detection device

[0057] 35 Fifth terminal

[0058] 36 Sixth terminal

[0059] 40 filter circuit

[0060] 41 First resistor

[0061] 42 Second resistor

[0062] 50, 550, 950, 1350, 1450 voltage detection circuit

[0063] 51 First terminal

[0064] 52 Second terminal

[0065] 53 Third terminal

[0066] 54 Fourth terminal

[0067] 60, 1160 Abnormal judgment circuit

[0068] 70, 570, 970, 1370 current generation circuit group

[0069] 71, 571, 971, 1371 First current generating circuit

[0070] 72, 572, 972, 1372 Second current generating circuit

[0071] 80, 1480 voltage detector

[0072] 81 First AD Converter

[0073] 82 Second AD converter

[0074] 90, 1490 multiplexers

[0075] 91, 1491 First Multiplexer

[0076] 92, 1492 Second Multiplexer

[0077] 1481 Comparator DETAILED DESCRIPTION

[0078] The following is an explanation of a specific example of a battery system involved in one embodiment of the present invention using the accompanying drawings. In addition, the embodiments to be described below are all preferred specific examples of the present invention. Therefore, the numerical values, shapes, materials, components, configuration positions of components, connection methods, processes, and the order of processes shown in the following embodiments are all examples, and their purpose is not to limit the present invention. Therefore, the components recorded in the technical solution showing the highest concept of the present invention among the components of the following embodiments are explained as arbitrary components.

[0079] In addition, each figure is a schematic diagram and is not a strict illustration. In addition, in each figure, substantially the same components are given the same reference numerals, and repeated descriptions are omitted or simplified.

[0080] (Implementation 1)

[0081] [1-1. Structure]

[0082] Figure 1 This is a block diagram showing the configuration of the battery system 1 in the first embodiment.

[0083] As shown in the figure, the battery system 1 includes a battery pack 10 , a voltage detection line group 20 , and an abnormality detection device 30 .

[0084] The battery pack 10 is composed of a plurality of batteries connected in series. The plurality of batteries include a first battery 11 and a second battery 12 connected in series to the anode side of the first battery 11 .

[0085] Here, although each battery constituting the battery pack 10 is assumed to be, for example, a lithium ion battery, the battery is not limited to a lithium ion battery and may be, for example, an electric double layer capacitor or an electrolytic capacitor.

[0086] Furthermore, here, the number of batteries constituting the battery pack 10 is shown as five in the figure, but the number is not limited to five as long as it is two or more, and may be three, seven, or the like, for example.

[0087] The voltage detection line group 20 is composed of a plurality of voltage detection lines that connect the anodes or cathodes of the plurality of batteries constituting the battery pack 10 to the plurality of terminals of the abnormality detection device 30 in a one-to-one manner.

[0088] The voltage detection line group 20 includes a first voltage detection line 21 and a second voltage detection line 22 .

[0089] One end of the first voltage detection line 21 is connected to the anode of the first battery 11 , and is also connected to the cathode of the second battery 12 connected in series to the anode side of the first battery 11 .

[0090] One end of the second voltage detection line 22 is connected to the anode of the second battery 12. The same end is also connected to the cathode of the battery connected in series to the anode side of the second battery 12.

[0091] The abnormality detection device 30 has a function of monitoring the status of each battery constituting the battery pack 10 , and is a so-called battery monitoring ECU (Electronic Control Unit). The device includes a filter circuit 40 , a voltage detection circuit 50 , and an abnormality determination circuit 60 .

[0092] Furthermore, the abnormality detection device 30 has a plurality of terminals connected to the respective voltage detection lines constituting the voltage detection line group 20 , including a fifth terminal 35 connected to the first voltage detection line 21 and a sixth terminal 36 connected to the second voltage detection line 22 .

[0093] The filter circuit 40 is composed of a plurality of low-pass filters formed of RC circuits including resistors and capacitors, and is used to smooth the voltage of each battery constituting the battery pack 10 .

[0094] The resistors constituting the low-pass filter include a first resistor 41 and a second resistor 42 .

[0095] The first resistor 41 is connected to the fifth terminal 35 .

[0096] The second resistor 42 is connected to the sixth terminal 36 .

[0097] The voltage detection circuit 50 includes a current generation circuit group 70 , a voltage detector 80 , and a multiplexer 90 .

[0098] Furthermore, the voltage detection circuit 50 has a plurality of terminals connected to the filter circuit 40 , including a first terminal 51 , a second terminal 52 , a third terminal 53 , and a fourth terminal 54 .

[0099] The first terminal 51 is connected to the other end of the first voltage detection line 21 (the end not connected to the anode of the first battery 11 ) via the first resistor 41 .

[0100] The second terminal 52 is connected to the other end of the first voltage detection line 21 via the first resistor 41 .

[0101] The third terminal 53 is connected to the other end of the second voltage detection line 22 (the end not connected to the anode of the second battery 12 ) via the second resistor 42 .

[0102] The fourth terminal 54 is connected to the other end of the second voltage detection line 22 without passing through the second resistor 42 .

[0103] That is, the abnormality detection device 30 includes a first connection path connecting the first terminal 51 and the fifth terminal 35 via the first resistor 41 , and a second connection path connecting the second terminal 52 and the fifth terminal 35 via the first resistor 41 .

[0104] The current generating circuit group 70 is composed of a plurality of current generating circuits, each of which is composed of a constant current source connected to the power supply potential and capable of being turned on and off (hereinafter referred to as a "sinking constant current source"), and a constant current source connected to the ground potential and capable of being turned on and off (hereinafter referred to as a "drawing constant current source"). These current generating circuits include a first current generating circuit 71 and a second current generating circuit 72.

[0105] Here, examples of the power supply side potential include the power supply potential of the voltage detection circuit 50, the highest potential of the voltage detection circuit 50, an internally generated potential generated within the voltage detection circuit 50, and an external potential supplied from an external input terminal. Furthermore, examples of the ground side potential include the ground potential of the voltage detection circuit 50, the lowest potential of the voltage detection circuit 50, an internally generated potential generated within the voltage detection circuit 50, and an external potential supplied from an external input terminal. This external potential can be supplied from a battery pack, for example.

[0106] These constant current sources are normally off and are turned on only when specific conditions are satisfied in the first abnormality detection process described later.

[0107] The first current generating circuit 71 is connected to the first terminal 51 , and draws current from the first terminal 51 or flows current into the first terminal 51 .

[0108] The second current generating circuit 72 is connected to the third terminal 53 , and draws current from the third terminal 53 or flows current into the third terminal 53 .

[0109] The multiplexer 90 is composed of a first multiplexer 91 and a second multiplexer 92. Thus, the multiplexer 90 selectively transmits one of a plurality of pairs of voltages, including a pair of voltages composed of the voltage of the first terminal 51 and the voltage of the second terminal 52, and a pair of voltages composed of the voltage of the third terminal 53 and the voltage of the fourth terminal 54, to the voltage detector 80.

[0110] Here, the terminal voltage refers to the potential of the target terminal (hereinafter referred to as the "target terminal"), using the potential of the cathode of the battery connected to the target terminal as the reference potential. Furthermore, transmitting the voltage of the target terminal to the voltage detector 80 means transmitting the potential of the target terminal and the reference potential to the voltage detector 80. Specifically, for example, if the target terminal is the third terminal 53, the multiplexer 90 transmits the potential of the third terminal 53 and the potential of the first terminal 51, which serves as the reference potential, to the voltage detector 80.

[0111] The voltage detector 80 includes a first AD converter 81 and a second AD converter 82. It detects the difference between a pair of voltages selected by the multiplexer 90. When the multiplexer 90 selects a pair of voltages consisting of the voltage at the first terminal 51 and the voltage at the second terminal 52, the voltage detector 80 detects the potential difference between the voltages at the first terminal 51 and the voltage at the second terminal 52 after converting them into digital values. When the multiplexer 90 selects a pair of voltages consisting of the voltage at the third terminal 53 and the voltage at the fourth terminal 54, the voltage detector 80 detects the potential difference between the voltages at the third terminal 53 and the voltage at the fourth terminal 54 after converting them into digital values.

[0112] The first AD converter 81 detects one voltage (the side selected by the first multiplexer 91 ) of a pair of voltages selected by the multiplexer 90 , and outputs a digital value of the detected voltage.

[0113] That is, the first AD converter 81 detects the potential difference between the potential of the target terminal transmitted from the first multiplexer 91 and the reference potential of the target terminal. For example, when the voltage of the fourth terminal 54 is selected by the first multiplexer 91, the voltage of the fourth terminal 54 is detected by detecting the difference between the potential of the fourth terminal 54 transmitted from the first multiplexer 91 and the potential of the second terminal 52 serving as the reference potential.

[0114] The second AD converter 82 detects the other voltage of the pair of voltages selected by the multiplexer 90 (the side selected by the second multiplexer 92 ), and outputs a digital value of the detected voltage.

[0115] That is, the second AD converter 82 detects the potential difference between the potential of the terminal transmitted from the second multiplexer 92 and the reference potential of the target terminal. For example, when the voltage of the third terminal 53 is selected by the second multiplexer 92, the voltage of the third terminal 53 is detected by detecting the difference between the potential of the third terminal 53 transmitted from the second multiplexer 92 and the potential of the first terminal 51 serving as the reference potential.

[0116] Here, the voltage detection by the first AD converter 81 and the voltage detection by the second AD converter 82 can be performed substantially simultaneously (within 1 ms).

[0117] Thus, the voltage detection circuit 50 has two systems for monitoring the voltages of the individual batteries constituting the battery pack 10 , namely, a main monitoring system consisting of the first multiplexer 91 and the first AD converter 81 , and an auxiliary monitoring system consisting of the second multiplexer 92 and the second AD converter 82 .

[0118] The main monitoring system and the auxiliary monitoring system are connected to each other via a resistor constituting a low-pass filter constituting the filter circuit 40. Furthermore, a plurality of current generating circuits constituting the current generating circuit group 70 are connected to the auxiliary monitoring system.

[0119] The abnormality determination circuit 60 is implemented by a processor included in the abnormality detection device 30 executing a memory (not shown) included in the abnormality detection device 30. Based on the potential difference detected by the voltage detection circuit 50, the abnormality determination circuit 60 detects connection abnormalities in the individual voltage detection lines that comprise the voltage detection line group 20, including the first voltage detection line 21. More specifically, the abnormality determination circuit 60 controls the on / off switching of the inflow constant current source and the outflow constant current source included in the current generation circuit group 70, controls the selection states of the first multiplexer 91 and the second multiplexer 92, and controls the operation of the first AD converter 81 and the second AD converter 82. Through these controls, the abnormality determination circuit 60 detects connection abnormalities in the individual voltage detection lines that comprise the voltage detection line group 20. The method for detecting this connection abnormality will be described in detail later in the section "First Abnormality Detection Processing."

[0120] Alternatively, the voltage detector 80 may simply convert the voltages of the respective terminals into digital values, and the abnormality determination circuit 60 may perform the detection of potential differences and the determination of connection abnormalities of the respective voltage detection lines. In other words, the voltage detector 80 may simply detect the voltages of the respective terminals, and the abnormality determination circuit 60 may perform the detection of potential differences and the determination of connection abnormalities of the respective voltage detection lines.

[0121] The operation of the battery system 1 having the above-described configuration will be described below with reference to the drawings.

[0122] [1-2. Work]

[0123] A characteristic operation of the battery system 1 is to perform a first abnormality detection process.

[0124] This first abnormality detection process is primarily performed by the voltage detection circuit 50 and detects connection abnormalities in the voltage detection lines included in the voltage detection line group 20. Any voltage detection line included in the voltage detection line group 20 can be subject to the first abnormality detection process. Here, the first voltage detection line 21 is used as a representative of these voltage detection lines and is considered to be the subject of connection abnormality detection.

[0125] For example, by sequentially executing the first abnormality detection process for each voltage detection line included in the voltage detection line group 20 , connection abnormalities can be detected for all the voltage detection lines included in the voltage detection line group 20 .

[0126] Figure 2 This is a flowchart of the first abnormality detection process.

[0127] The first abnormality detection process starts when specified conditions are met (for example, a specified time has passed after the voltage detection circuit 50 is started; a specified time has passed after the last first abnormality detection process was executed; a specified operation is performed on the voltage detection circuit 50 by a user using the voltage detection circuit 50, etc.).

[0128] At the start of the first abnormality detection process, the abnormality determination circuit 60 determines whether the state of the first battery 11, a battery whose anode is connected to the first voltage detection line 21 (the voltage detection line to be detected for connection abnormality), is in the overdischarge range (step S5). Here, the abnormality determination circuit 60 determines that the first battery 11 is in the overdischarge range if the most recently measured voltage of the first battery 11 is less than a predetermined value (e.g., 1.0 V). If the voltage of the first battery 11 is greater than the predetermined value, the abnormality determination circuit 60 determines that the first battery 11 is not in the overdischarge range. Alternatively, for example, if the voltage of the first battery 11 has not been measured recently, the first battery 11 may be determined to be not in the overdischarge range.

[0129] In the processing of step S5, when it is determined that it is not an over-discharge area (step S5: No), the abnormality judgment circuit 60 turns on the constant current source for leading out of the first current generating circuit 71, and the first current generating circuit 71 is a current generating circuit connected to the voltage detection line that is the detection object of the connection abnormality, that is, the first voltage detection line 21 (step S10).

[0130] Furthermore, the abnormality determination circuit 60 controls the selection states of the first multiplexer 91 and the second multiplexer 92 so that the multiplexer 90 selects a pair of voltages consisting of the voltage at the first terminal 51 and the voltage at the second terminal 52. Furthermore, the abnormality determination circuit 60 controls the operation of the first AD converter 81 and the second AD converter 82 so that the first AD converter 81 and the second AD converter 82 operate at substantially the same timing (within 1 ms). This causes the voltage detector 80 to detect the difference (Vm-Vs) between the voltage at the second terminal 52 (voltage Vm detected by the primary monitoring system) and the voltage at the first terminal 51 (voltage Vs detected by the secondary monitoring system) (step S15).

[0131] When the difference (Vm-Vs) between the voltage Vm of the second terminal 52 and the voltage Vs of the first terminal 51 is detected, the abnormality judgment circuit 60 judges whether the value of Vm-Vs is less than a preset abnormality judgment value (threshold) Vth_a (for example, 0.5V) (step S20).

[0132] In the process of step S20 , when the value of Vm-Vs is less than or equal to Vth_a (step S20 : ​​Yes), the abnormality determination circuit 60 determines whether there is a connection abnormality in the first voltage detection line 21 (step S25 ).

[0133] In the process of step S20 , when the value of Vm-Vs is not less than Vth_a (step S20 : ​​No), the abnormality determination circuit 60 determines that there is no connection abnormality in the first voltage detection line 21 (step S30 ).

[0134] When the process of step S25 is completed or when the process of step S30 is completed, the abnormality determination circuit 60 turns off the constant current source for extraction of the first current generating circuit 71 (step S35 ).

[0135] Hereinafter, the determination of the presence or absence of a connection abnormality by the abnormality determination circuit 60 in the processing from “Yes” in step S5 to step S35 will be described in detail with reference to the drawings.

[0136] Figure 3AThe pattern diagram shows the transition of the voltage Vm detected by the main monitoring system, the transition of the voltage Vs detected by the auxiliary monitoring system, and the transition of Vm-Vs when there is no connection abnormality due to disconnection of the first voltage detection line 21.

[0137] Figure 3B The schematic diagram shows the transition of the voltage Vm detected by the main monitoring system, the transition of the voltage Vs detected by the auxiliary monitoring system, and the transition of Vm-Vs when a connection abnormality due to a break occurs in the first voltage detection line 21.

[0138] Here, it is assumed that the voltage of the first battery 11 is 3.7V, and among the filters included in the filter circuit 40, the filter constant on the main monitoring system side is Rm=50Ω (the resistor generating this resistance value will be referred to as "resistor m" hereinafter), Cm=10nF, and the filter constant on the auxiliary monitoring system side is Rs=1KΩ (the resistor generating this resistance value is the first resistor 41), Cs=10nF, and the current of the constant current source for extraction of the first current generating circuit 71 is 1mA.

[0139] Furthermore, in the processing of step S10, the moment when the constant current source for lead-out of the first current generating circuit 71 is turned on is moment t10; in the processing of step S15, the moment when (Vm-Vs) is detected is moment t15; and in the processing of step S35, the moment when the constant current source for lead-out of the first current generating circuit 71 is turned off is moment t35.

[0140] (a) When the first voltage detection line 21 does not have a connection abnormality due to disconnection (see Figure 3A ), voltage Vm detected by the main monitoring system remains constant at 3.7V, the voltage of battery 11, even when the constant current source for extraction of first current generating circuit 71 is turned on at time t10. In contrast, voltage Vs detected by the auxiliary monitoring system, when the constant current source for extraction of first current generating circuit 71 is turned on at time t10, becomes 2.7V, the value obtained by subtracting 1V (=1KΩ×1mA) generated by the constant current (1mA) flowing into first resistor 41 (1KΩ) from the voltage of battery 11 (3.7V). Therefore, Vm-Vs detected at time t15 is 1V.

[0141] In addition, (b) when a connection abnormality occurs in the first voltage detection line 21 due to a disconnection (see Figure 3B), when the constant current source for extraction of the first current generating circuit 71 is turned on at time t10, the first terminal 51 is not connected to the anode of the first battery 11 and is in a high-impedance state. Therefore, the potential of the first terminal 51 drops until the constant current source for extraction of the first current generating circuit 71 stops extracting current. As a result, the voltage Vs detected by the auxiliary monitoring system drops to the lower limit value that can be detected by the second AD converter 82 (here, for example, 0V). The same applies to the second terminal 52. Since it is not connected to the anode of the first battery 11 and is in a high-impedance state, the potential of the second terminal 52 drops until the constant current source for extraction of the first current generating circuit 71 stops extracting current. Therefore, the voltage Vm detected by the main monitoring system also drops to the lower limit value that can be detected by the first AD converter 81 (here, for example, 0V). Therefore, the value Vm-Vs detected at time t15 is 0V.

[0142] In this manner, by setting the abnormality determination value Vth_a to, for example, 0.5 V, it is possible to detect whether or not there is a connection abnormality due to a disconnection.

[0143] Since the value of Vm-Vs varies depending on the constant of the filter circuit and the current value of the constant current source, the abnormality determination value Vth_a may be set to meet these conditions.

[0144] Next, return to Figure 2 , continue with the description of the first abnormality detection process.

[0145] In the processing of step S5, when it is determined that it is an over-discharge area (for example, 1.0V) (step S5: yes), the abnormality judgment circuit 60 turns on the inflow constant current source of the first current generating circuit 71, which is a current generating circuit connected to the voltage detection line that is the detection object of the connection abnormality, namely the first voltage detection line 21 (step S40).

[0146] Furthermore, the abnormality determination circuit 60 controls the selection states of the first multiplexer 91 and the second multiplexer 92 so that the multiplexer 90 selects a pair of voltages consisting of the voltage at the first terminal 51 and the voltage at the second terminal 52. Furthermore, the abnormality determination circuit 60 controls the operation of the first AD converter 81 and the second AD converter 82 so that the first AD converter 81 and the second AD converter 82 operate at substantially the same timing (within 1 ms). This causes the voltage detector 80 to detect the difference (Vm-Vs) between the voltage at the second terminal 52 (voltage Vm detected by the primary monitoring system) and the voltage at the first terminal 51 (voltage Vs detected by the secondary monitoring system) (step S45).

[0147] When the difference (Vm-Vs) between the voltage Vm of the second terminal 52 and the voltage Vs of the first terminal 51 is detected, the abnormality judgment circuit 60 judges whether the value of Vm-Vs is greater than a preset abnormality judgment value (threshold) Vth_b (for example, 0.5V) (step S50).

[0148] In the process of step S50 , when the value of Vm-Vs is greater than or equal to Vth_b (step S50 : Yes), the abnormality determination circuit 60 determines that there is a connection abnormality in the first voltage detection line 21 (step S55 ).

[0149] In the process of step S50 , when the value of Vm-Vs is not greater than Vth (step S50 : No), the abnormality determination circuit 60 determines that there is no connection abnormality in the first voltage detection line 21 (step S60 ).

[0150] When the process of step S55 is completed, or when the process of step S60 is completed, the abnormality determination circuit 60 turns off the inflow constant current source of the first current generating circuit 71 (step S65 ).

[0151] The following describes in detail the determination of whether or not there is a connection abnormality performed by the abnormality determination circuit 60 in the processing from “No” in step S5 to step S65 using the drawings.

[0152] Figure 4A The pattern diagram shows the transition of the voltage Vm detected by the main monitoring system, the transition of the voltage Vs detected by the auxiliary monitoring system, and the transition of Vm-Vs when there is no connection abnormality due to disconnection of the first voltage detection line 21.

[0153] Figure 4B The schematic diagram shows the transition of the voltage Vm detected by the main monitoring system, the transition of the voltage Vs detected by the auxiliary monitoring system, and the transition of Vm-Vs when a connection abnormality due to disconnection occurs in the first voltage detection line 21.

[0154] (a) When the first voltage detection line 21 does not have a connection abnormality due to disconnection (see Figure 4A), voltage Vm detected by the main monitoring system remains constant at 3.7V, the voltage of battery 11, even when the constant current source for inflow of first current generating circuit 71 is turned on at time t10. In contrast, voltage Vs detected by the auxiliary monitoring system changes from the voltage of battery 11 (1.0V) to the value obtained by adding the voltage generated by the constant current (1mA) flowing through first resistor 41 (1kΩ) (1V (=1kΩ x 1mA)), i.e., to 2.0V, when the constant current source for inflow of first current generating circuit 71 is turned on at time t10. Therefore, Vm - Vs detected at time t15 is -1V.

[0155] In addition, (b) when a connection abnormality occurs in the first voltage detection line 21 due to a disconnection (see Figure 4B ). At time t10, when the inflow constant current source of the first current generating circuit 71 is turned on, the first terminal 51 is disconnected from the anode of the first battery 11 and enters a high-impedance state. Therefore, the potential of the first terminal 51 increases until no current flows through the inflow constant current source of the first current generating circuit 71. Consequently, the voltage Vm detected by the auxiliary monitoring system increases until it reaches the upper limit detectable by the AD converter (here, for example, 5V). The same applies to the second terminal 52. Since it is disconnected from the anode of the first battery 11 and enters a high-impedance state, the potential of the second terminal 52 increases until no current flows through the inflow constant current source of the first current generating circuit 71. Consequently, the voltage Vs detected by the main monitoring system also increases until it reaches the upper limit detectable by the AD converter (here, for example, 5V). Thus, the voltage Vm-Vs detected at time t15 is 0V.

[0156] Therefore, by setting the abnormality determination value Vth_b to 0.5 V, for example, it is possible to detect whether or not there is a connection abnormality due to a disconnection.

[0157] Since the value of Vm-Vs varies depending on the constant of the filter circuit and the current value of the constant current source, the abnormality determination value Vth_b may be set to meet these conditions.

[0158] The following returns to Figure 2 , then the first abnormality detection process is described.

[0159] When the process of step S35 is completed, or when the process of step S65 is completed, the voltage detection circuit 50 ends the first abnormality detection process.

[0160] [1-3. Effects, etc.]

[0161] According to the battery system 1 described above, the detection of the voltage at the second terminal 52 by the first AD converter 81 of the main monitoring system and the detection of the voltage at the first terminal 51 by the second AD converter 82 of the auxiliary monitoring system are performed approximately simultaneously (within 1 ms). Therefore, the period between the detection timing of the voltage at the first terminal 51 and the detection timing of the voltage at the second terminal 52 is less susceptible to fluctuations in the battery voltage due to, for example, the charging and discharging of the battery 11, thereby enabling highly accurate detection of connection abnormalities.

[0162] Furthermore, there is no need to store past voltage detection values ​​in a RAM (Random Access Memory) or other storage area in order to detect connection anomalies, making software design easier.

[0163] Furthermore, during the execution of the first abnormality detection process, if the target voltage connection line does not have an abnormality, the auxiliary monitoring system will be affected by the activation of the current generating circuit, but the main monitoring system will not be affected by the activation of the current generating circuit. Therefore, even during the execution of the first abnormality detection process, the main monitoring system can accurately detect the voltage of each battery cell constituting the battery pack 10 by utilizing the main monitoring system.

[0164] (Implementation Method 2)

[0165] Here, a battery system according to a second embodiment will be described as one aspect of the present invention. The battery system according to the second embodiment is a battery system in which a portion of the configuration is modified from the battery system 1 according to the first embodiment.

[0166] In the example of the battery system 1 according to the first embodiment, each current generating circuit constituting the current generating circuit group 70 is configured to include both a constant current source for sinking and a constant current source for drawing. In contrast, in the example of the battery system according to the second embodiment, each current generating circuit constituting the current generating circuit group is configured to include only a constant current source for drawing, without including a constant current source for sinking.

[0167] The battery system will be described below in detail with reference to the drawings, focusing on differences from the battery system 1 in the first embodiment.

[0168] [2-1. Structure]

[0169] Figure 5 This is a block diagram showing the configuration of the battery system 2 in the second embodiment.

[0170] This battery system 2 is modified from the battery system 1 in the first embodiment. Specifically, the current generating circuit group 70 in the first embodiment is replaced with a current generating circuit group 570. Furthermore, with this change, the voltage detection circuit 50 and the abnormality detection device 30, which are functional blocks in the upper layer of the current generating circuit group 70 in the first embodiment, are replaced with a voltage detection circuit 550 and an abnormality detection device 530, respectively.

[0171] The current generating circuit group 570 is composed of a plurality of current generating circuits each consisting of a constant current source for extraction, which is a constant current source connected to a ground potential and capable of switching on and off.

[0172] That is, the current generating circuit group 570 is different from the current generating circuit group 70 in the first embodiment in that the inflow constant current source is deleted from each current generating circuit constituting the current generating circuit group 70 .

[0173] These current generating circuits include a first current generating circuit 571 obtained by removing the inflow constant current source from the first current generating circuit 71 in embodiment 1, and a second current generating circuit 572 obtained by removing the inflow constant current source from the second current generating circuit 72 in embodiment 1.

[0174] The operation of the battery system 2 configured as described above will be described below with reference to the drawings.

[0175] [2-2. Work]

[0176] The characteristic operation of battery system 2 includes a second abnormality detection process, which is a modification of the first abnormality detection process in Embodiment 1, and a third abnormality detection process, which is a modification of the second abnormality detection process. These processes are described below in order.

[0177] [2-2-1. Second abnormality detection process]

[0178] Figure 6 This is a flowchart of the second abnormality detection process.

[0179] In this figure, the processing of step S610 is the same as the processing of step S10 in the first abnormality detection process in Embodiment 1, except that "first current generating circuit 71" is replaced with "first current generating circuit 571." Furthermore, the processing from step S615 to step S635 is the same as the processing from step S15 to step S35 in the first abnormality detection process in Embodiment 1.

[0180] Therefore, each process from step S610 to step S635 is substantially the same as each process from step S10 to step S35 of the first abnormality detection process in Embodiment 1. Therefore, since these processes have already been described, repeated description is omitted here.

[0181] In the second abnormality detection process, the lower limit value detectable by the first AD converter 81 and the lower limit value detectable by the second AD converter 82 are described here as, for example, 0 V (same as the description of the first abnormality detection process in the first embodiment).

[0182] In this configuration example, if the voltage of the first battery 11 falls below 1.0V, an overdischarge region, for example, and the first voltage detection line 21 is not broken, the voltage at the first terminal 51 falls below 0V, which is lower than the lower limit of the voltage detected by the auxiliary monitoring system. To address this issue, by setting the lower limit detectable by the first AD converter 81 and the lower limit detectable by the second AD converter 82 to, for example, -2V, it is possible to accurately detect a connection abnormality even when the battery voltage falls below 1.0V, an overdischarge region.

[0183] [2-2-2. Third Abnormality Detection Process]

[0184] The second abnormality detection process uses the voltage of a battery whose anode is connected to a voltage detection line to detect a connection abnormality in the voltage detection line. As a representative example, the voltage of a first battery 11 whose anode is connected to the first voltage detection line 21 is used to detect a connection abnormality in the first voltage detection line 21.

[0185] In contrast, the third abnormality detection process utilizes the voltage of a battery whose cathode is connected to a voltage detection line for which connection abnormality detection is to be performed, thereby detecting a connection abnormality in the voltage detection line. As a representative example, the voltage of a second battery 12 whose cathode is connected to the first voltage detection line is used to detect a connection abnormality in the first voltage detection line 21.

[0186] Figure 7 This is a flowchart of the third abnormality detection process.

[0187] The third abnormality detection process starts when specified conditions are met (for example, a specified time has passed since the voltage detection circuit 550 was activated; a specified time has passed since the last execution of the third abnormality detection process; a specified operation has been performed on the voltage detection circuit 550 by a user using the voltage detection circuit 550, etc.).

[0188] When the third abnormality detection processing starts, the abnormality judgment circuit 60 turns on the constant current source for leading out the first current generating circuit 71, which is a current generating circuit connected to the voltage detection line that is the detection object of the connection abnormality, namely the first voltage detection line 21 (step S710).

[0189] The abnormality determination circuit 60 then controls the selection states of the first multiplexer 91 and the second multiplexer 92 so that the multiplexer 90 selects a pair of voltages consisting of the voltage at the third terminal 53 and the voltage at the fourth terminal 54. Furthermore, the abnormality determination circuit 60 controls the operation of the first AD converter 81 and the second AD converter 82 so that the voltage detector 80 operates the first AD converter 81 and the second AD converter 82 at substantially the same timing (within 1 ms). This allows the voltage detector 80 to detect the difference (Vm-Vs) between the voltage at the fourth terminal 54 (voltage Vm detected by the primary monitoring system) and the voltage at the third terminal 53 (voltage Vs detected by the secondary monitoring system) (step S715).

[0190] When the difference (Vm-Vs) between the voltage Vm of the fourth terminal 54 and the voltage Vs of the third terminal 53 is detected, the abnormality judgment circuit 60 judges whether the value of Vm-Vs is greater than a preset abnormality judgment value (threshold) Vth_b (for example, 0.5V) (step S720).

[0191] In the process of step S720 , when the value of Vm-Vs is greater than or equal to Vth_b (step S720 : Yes), the abnormality determination circuit 60 determines that there is a connection abnormality in the first voltage detection line 21 (step S725 ).

[0192] In the process of step S720 , if the value of Vm-Vs is not greater than Vth_b (step S720 : No), the abnormality determination circuit 60 determines that there is no connection abnormality in the first voltage detection line 21 (step S730 ).

[0193] When the process of step S725 is completed, or when the process of step S30 is completed, the abnormality determination circuit 60 turns off the constant current source for extraction of the first current generating circuit 71 (step S735 ).

[0194] The following describes in detail the determination of whether or not there is a connection abnormality by the abnormality determination circuit 60 in the processing from step S710 to step S735 using the accompanying drawings.

[0195] Figure 8AThe schematic diagram shows the transition of the voltage Vm detected by the main monitoring system, the transition of the voltage Vs detected by the auxiliary monitoring system, and the transition of Vm-Vs when the first voltage detection line 21 does not have a connection abnormality due to a break.

[0196] Figure 8B The schematic diagram shows the transition of the voltage Vm detected by the main monitoring system, the transition of the voltage Vs detected by the auxiliary monitoring system, and the transition of Vm-Vs when a connection abnormality due to disconnection occurs in the first voltage detection line 21.

[0197] (a) When the first voltage detection line 21 does not have a connection abnormality due to disconnection (see Figure 8A ), voltage Vm detected by the main monitoring system remains constant at 3.7V, the voltage of battery 12, even when the constant current source for extracting current from first current generating circuit 71 is turned on at time t10. In contrast, voltage Vs detected by the auxiliary monitoring system, when the constant current source for extracting current from first current generating circuit 71 is turned on at time t10, becomes 4.7V, after adding the voltage (1V (=1KΩ×1mA)) generated by the constant current (1mA) flowing into first resistor 41 (1KΩ) to the voltage of battery 12 (3.7V). Therefore, Vm-Vs detected at time t15 becomes -1V.

[0198] Furthermore, (b) when a connection abnormality occurs in the first voltage detection line 21 due to a disconnection (see Figure 8B ). At time t10, when the inflow constant current source of the first current generating circuit 71 is turned on, the third terminal 53 is disconnected from the cathode of the second battery 12 and enters a high-impedance state. Consequently, the potential of the third terminal 53 increases until no current flows from the extraction constant current source of the first current generating circuit 71. Consequently, the voltage Vs detected by the auxiliary monitoring system increases until it reaches the upper limit detectable by the AD converter (here, for example, 5V). The same applies to the fourth terminal 54. Since it is disconnected from the cathode of the second battery 12 and enters a high-impedance state, the potential of the fourth terminal 54 increases until no current flows from the inflow constant current source of the first current generating circuit 71. Consequently, the voltage Vm detected by the main monitoring system also increases until it reaches the upper limit detectable by the AD converter (here, for example, 5V). Thus, the voltage Vm-Vs detected at time t15 becomes 0V.

[0199] Therefore, by setting the abnormality determination value Vth_n to, for example, 0.5 V, it is possible to detect whether or not there is a connection abnormality due to a disconnection.

[0200] Since the value of Vm-Vs varies according to the constant of the filter circuit and the current value of the constant current source, the abnormality determination value Vth_b can also be set to meet this condition.

[0201] [2-3. Effects, etc.]

[0202] According to the battery system 2 described above, the same effects as those of the battery system 1 in the first embodiment can be obtained.

[0203] (Implementation 3)

[0204] Here, as one aspect of the present invention, a battery system in a third embodiment will be described. The battery system in the third embodiment is a system in which a portion of the configuration of the battery system 1 in the first embodiment is modified.

[0205] In the example shown in the battery system 1 of the first embodiment, each current generating circuit constituting the current generating circuit group 70 includes both a constant current source for sinking and a constant current source for drawing. In contrast, in the example shown in the battery system of the third embodiment, each current generating circuit constituting the current generating circuit group does not include a constant current source for drawing, but only includes a constant current source for sinking.

[0206] Hereinafter, this battery system will be described in detail with reference to the drawings, focusing on the differences between it and the battery system 1 in the first embodiment.

[0207] [3-1. Structure]

[0208] Figure 9 This is a block diagram showing the configuration of the battery system 3 in the third embodiment.

[0209] This battery system 3 differs from the battery system 1 in the first embodiment in that the current generating circuit group 70 in the first embodiment is replaced with a current generating circuit group 970. Furthermore, with this replacement, the voltage detection circuit 50 and the abnormality detection device 30, which are functional blocks in the upper layer of the current generating circuit group 70 in the first embodiment, are replaced with a voltage detection circuit 950 and an abnormality detection device 930, respectively.

[0210] The current generating circuit group 970 is composed of a plurality of current generating circuits, each of which is composed of an inflow constant current source that can be turned on and off.

[0211] That is, the current generating circuit group 970 is different from the current generating circuit group 70 in the first embodiment, in that the extraction constant current source is deleted from each current generating circuit constituting the current generating circuit group 70 .

[0212] The current generating circuit includes a first current generating circuit 971 and a second current generating circuit 972. The first current generating circuit 971 deletes the lead-out constant current source compared to the first current generating circuit 71 in embodiment 1, and the second current generating circuit 972 deletes the lead-out constant current source compared to the second current generating circuit 72 in embodiment 1.

[0213] The operation of the battery system 3 having the above-described configuration will be described below with reference to the accompanying drawings.

[0214] [3-2. Work]

[0215] The characteristic operation of the battery system 3 is the fourth abnormality detection process, which is a process in which some processes are modified from the first abnormality detection process in Embodiment 1. These processes will be described below in order.

[0216] Figure 10 This is a flowchart of the fourth abnormality detection process.

[0217] In this figure, the processing of step S1040 is the same as the processing of step S40 in the first abnormality detection process in Embodiment 1, with "first current generating circuit 71" replaced by "first current generating circuit 971." Furthermore, the processing of steps S1045 through S1065 is the same as the processing of steps S45 through S65 in the first abnormality detection process in Embodiment 1.

[0218] Therefore, each process of step S1040 to step S1065 is substantially the same as each process of step S40 to step S65 of the first abnormality detection process in Embodiment 1. Therefore, since these processes have already been described, repeated description is omitted here.

[0219] In addition, it is explained here that in the second abnormality detection process, the upper limit value that can be detected by the first AD converter 81 and the upper limit value that can be detected by the second AD converter 82 are set to 5.0 V, for example (the same as the description of the first abnormality detection process in embodiment 1).

[0220] In this configuration example, if the voltage of the first battery 11 is, for example, in the overcharge range of 4.0V or higher, and if the first voltage detection line 21 is not broken, the voltage at the first terminal 51 will be 5.0V or higher, exceeding the upper limit of the voltage detected by the auxiliary monitoring system. To address this issue, by setting the upper limit detectable by the first AD converter 81 and the upper limit detectable by the second AD converter 82 to 7.0V, for example, it is possible to accurately detect a connection abnormality even when the battery voltage is in the overcharge range of 4.0V or higher.

[0221] [3-3. Effects, etc.]

[0222] According to the battery system 3 described above, the same effects as those of the battery system 1 in the first embodiment can be obtained.

[0223] (Implementation 4)

[0224] Here, a battery system according to a fourth embodiment will be described as one aspect of the present invention. The battery system according to the fourth embodiment is a battery system in which the configuration of the battery system 1 according to the first embodiment is partially modified.

[0225] In the battery system 1 described in the first embodiment, the voltage detection circuit 50 performs the first abnormality detection process. In contrast, in the battery system of the fourth embodiment, the voltage detection circuit performs the fourth abnormality detection process, which is a partial modification of the first abnormality detection process.

[0226] The following description will focus on the differences between this battery system and the battery system 1 in the first embodiment, with reference to the drawings.

[0227] [4-1. Structure]

[0228] Figure 11 This is a block diagram showing the configuration of the battery system 4 in the fourth embodiment.

[0229] The hardware of battery system 4 remains unchanged from that of battery system 1 in Embodiment 1. However, the software executed by battery system 4 is a result of partially modifying the software executed by battery system 1 in Embodiment 1. Therefore, in battery system 4, the abnormality determination circuit 60 is modified to an abnormality determination circuit 1160 compared to battery system 1 in Embodiment 1. Furthermore, with this modification, the abnormality detection device 30, which serves as a functional block in the upper layer of abnormality determination circuit 60 in Embodiment 1, is modified to an abnormality detection device 1130.

[0230] Abnormality determination circuit 460, like abnormality determination circuit 60 in Embodiment 1, detects a connection abnormality in each of the voltage detection lines constituting voltage detection line group 20, including first voltage detection line 21, based on the potential difference detected by voltage detection circuit 50. However, whereas abnormality determination circuit 60 in Embodiment 1 detected this connection abnormality by executing the first abnormality detection process, abnormality determination circuit 460 detects this connection abnormality by executing a fifth abnormality detection process that is a partially modified version of the first abnormality detection process.

[0231] Furthermore, the voltage detector 80 converts the voltages of the terminals into digital values, and the detection of potential differences and the detection of connection abnormalities of the voltage detection lines can be performed by the abnormality determination circuit 1160. In other words, the voltage detector 80 only detects the voltages of the terminals, and the detection of potential differences and the detection of connection abnormalities of the voltage detection lines are performed by the abnormality determination circuit 1160.

[0232] The operation of the battery system 4 having the above-described configuration will be described below with reference to the drawings.

[0233] [4-2. Work]

[0234] Figure 12 This is a flowchart of the fifth abnormality detection process.

[0235] In this figure, the processes from steps S1210 to S1265 are the same as the processes from steps S10 to S65 of the first abnormality detection process in Embodiment 1, with "abnormality determination circuit 60" replaced by "abnormality determination circuit 1160." Since these processes have already been described, a repeated explanation is omitted here, and the description focuses on the process of step S1205.

[0236] At the start of the fifth abnormality detection process, the abnormality determination circuit 1160 determines whether the constant current source for drawing out the first current generating circuit 71 connected to the first voltage detection line 21 was turned on during the fifth abnormality detection process previously executed on the first voltage detection line 21, which is the voltage detection line to be detected for the connection abnormality. In other words, it determines whether the process proceeded to step S1210 (step S1205) during the fifth abnormality detection process previously executed on the first voltage detection line 21. For example, if the fifth abnormality detection process has not been executed on the first voltage detection line 21 in the past, it can be determined that the constant current source for drawing out the first current generating circuit 71 connected to the first voltage detection line 21 was turned on during the fifth abnormality detection process previously executed.

[0237] In the processing of step S1205, when it is judged that the constant current source for lead-out of the first current generating circuit 71 is connected, that is, in the fifth abnormality detection processing last performed on the first voltage detection line 21, when it is judged that the processing of step S1210 is entered (step S1205: yes), the processing of step S1240 is entered.

[0238] In the processing of step S1205, when it is determined that the constant current source for the lead-out of the first current generating circuit 71 is not connected, that is, in the fifth abnormality detection processing last performed on the first voltage detection line 21, it is determined not to enter the processing of step S1210 but to enter the processing of step S1240 (step S1205: No), the processing of step S1210 is entered.

[0239] [4-3. Effects, etc.]

[0240] According to the battery system 4 described above, in addition to the same effects as those of the battery system 1 in the first embodiment, the following effects can be obtained.

[0241] Specifically, when the fifth abnormality detection process is repeatedly executed by the battery system 4, current flows into and out of each battery cell constituting the battery pack 10 alternately. Therefore, even when the detection of a connection abnormality in the voltage detection line is repeated, it is possible to avoid the situation where current flows into and out of each battery cell constituting the battery pack 10 in an arbitrary manner.

[0242] (Implementation 5)

[0243] Here, a battery system according to a fifth embodiment will be described as one aspect of the present invention. The battery system according to the fifth embodiment is a system in which the configuration of the battery system 1 according to the first embodiment is partially modified.

[0244] In the example shown in the battery system 1 of the first embodiment, each current generating circuit constituting the current generating circuit group 70 is composed of a constant current source for inflow and a constant current source for outflow. In contrast, in the example shown in the battery system of the fifth embodiment, each current generating circuit constituting the current generating circuit group is constituted by a switch for short-circuiting each battery constituting the battery pack 10 in the auxiliary monitoring system.

[0245] Hereinafter, this battery system will be described in detail with reference to the drawings, focusing on differences from the battery system 1 in the first embodiment.

[0246] [5-1. Structure]

[0247] Figure 13 This is a block diagram showing the configuration of the battery system 5 in the fifth embodiment.

[0248] The battery system 5 is modified from the battery system 1 in the first embodiment in that the current generating circuit group 70 in the first embodiment is replaced with a current generating circuit group 1370. Furthermore, with this modification, the voltage detection circuit 50 and the abnormality detection device 30, which are functional blocks in the upper layer of the current generating circuit group 70 in the first embodiment, are replaced with a voltage detection circuit 1350 and an abnormality detection device 1330, respectively.

[0249] In the auxiliary monitoring system, the current generating circuit group 1370 is composed of a plurality of current generating circuits each including a switch for short-circuiting the anode and cathode of each battery cell constituting the battery pack 10. These current generating circuits include a first current generating circuit 1371 and a second current generating circuit 1372.

[0250] In the auxiliary monitoring system, the first current generating circuit 1371 is configured by a switch for short-circuiting the anode and cathode of the first battery 11 via the first resistor 41 .

[0251] In the auxiliary monitoring system, the second current generating circuit 1372 is formed by a switch for short-circuiting the anode and cathode of the second battery 12 via the second resistor 42 .

[0252] The switches constituting the current generating circuit including the first current generating circuit 1371 and the second current generating circuit 1372 are implemented by, for example, MOSFETs (Metal Oxide Semiconductor Field Effect Transistors).

[0253] These switches can also serve as balancing switches for balancing the individual batteries comprising the battery pack 10. Balancing is a function that selects batteries to be discharged according to their remaining capacity, turns on the balancing switches corresponding to the selected batteries, discharges the batteries, and balances the remaining capacity of the individual batteries.

[0254] Furthermore, each current generating circuit may include not only a switch but also a resistor connected in series with the switch.

[0255] Next, the operation of the battery system 1 having the above-described configuration will be described.

[0256] [5-2. Work]

[0257] When the switch of the first current generating circuit 1371 is turned on, a short-circuit current flows from the anode to the cathode of the first battery 11. In this way, the first current generating circuit 1371 functions as a current source that draws current from the first terminal 51.

[0258] When the switch of the second current generating circuit 1372 is turned on, a short-circuit current flows from the anode to the cathode of the second battery 12. Therefore, the second current generating circuit 1372 functions as a current source that flows current into the first terminal 51 and extracts current from the third terminal 53.

[0259] In this manner, each current generating circuit constituting the current generating circuit group 1370 functions as a current source similar to each current generating circuit constituting the current generating circuit group 70 in the first embodiment.

[0260] Therefore, by the same method as the battery system 1 in the first embodiment, it is possible to detect a connection abnormality in each voltage detection line constituting the voltage detection line group 20 .

[0261] [5-3. Effects, etc.]

[0262] According to the battery system 5 described above, the same effects as those of the battery system 1 in the first embodiment can be obtained.

[0263] (Implementation 6)

[0264] Here, as one aspect of the present invention, a battery system in a sixth embodiment in which a part of the configuration of the battery system 2 in the second embodiment is modified will be described.

[0265] In the example shown in the battery system 2 of the second embodiment, the voltage detector 80 includes a first AD converter 81 and a second AD converter 82. In contrast, in the example shown in the battery system of the sixth embodiment, the voltage detector includes a comparator instead of an AD converter.

[0266] Hereinafter, this battery system will be described in detail with reference to the drawings, focusing on differences from the battery system 2 in the second embodiment.

[0267] [6-1. Structure]

[0268] Figure 14 This is a block diagram showing the configuration of the battery system 6 in the sixth embodiment.

[0269] This battery system 6 is a variation of the battery system 2 in the second embodiment. The voltage detector 80 and multiplexer 90 in the second embodiment are replaced with a voltage detector 1480 and a multiplexer 1490, respectively. Furthermore, with this replacement, the voltage detection circuit 550 and the abnormality detection device 530, which are upper-layer functional blocks of the voltage detector 80 and multiplexer 90 in the second embodiment, are replaced with a voltage detection circuit 1450 and an abnormality detection device 1430, respectively.

[0270] The multiplexer 1490 includes a first multiplexer 1491 and a second multiplexer 1492. The multiplexer 1490 selectively transmits one of a plurality of voltage pairs, including a pair of voltages formed by the voltage of the first terminal 51 and the voltage of the second terminal 52, and a pair of voltages formed by the voltage of the third terminal 53 and the voltage of the fourth terminal 54, to the voltage detector 1480.

[0271] Here, the voltage of the terminal refers to the voltage of the target terminal with the ground potential as a reference. Furthermore, transmitting the voltage of the target terminal to the voltage detector 1480 means transmitting the potential of the target terminal to the voltage detector 1480 .

[0272] As described above, the voltage detection circuit 1450 includes two systems for monitoring the voltages of the individual batteries constituting the battery pack 10 , namely, a main monitoring system including the first multiplexer 1491 and an auxiliary monitoring system including the second multiplexer 1492 .

[0273] The voltage detector 1480 includes a comparator 1481 and detects the difference between a pair of voltages selected by the multiplexer 1490 .

[0274] The comparator 1481 detects the difference between the voltage selectively transmitted by the first multiplexer 1491 and the voltage selectively transmitted by the second multiplexer 1492. That is, when the first multiplexer 1491 selectively transmits the voltage of the first terminal 51 and the second multiplexer 1492 selectively transmits the voltage of the second terminal 52, the voltage detector 1480 detects the difference between the voltage of the first terminal 51 and the voltage of the second terminal 52.

[0275] The comparator 1481 can set an offset value Vth. Specifically, when the offset value Vth is set, the comparator 1481 outputs a logical value of "1" if the first and second voltages being compared are equal to or greater than the offset value Vth, and outputs a logical value of "0" if the first and second voltages being compared are not equal to or greater than the offset value Vth.

[0276] As an example, the comparator 1481 is implemented by an analog comparator.

[0277] The operation of the battery system 6 having the above-described configuration will be described below with reference to the drawings.

[0278] [6-2. Work]

[0279] As a characteristic operation of the battery system 6 , a sixth abnormality detection process is performed.

[0280] The sixth abnormality detection process is primarily performed by the voltage detection circuit 1450 and detects connection abnormalities in the voltage detection lines included in the voltage detection line group 20. Any voltage detection line included in the voltage detection line group 20 can be the subject of the sixth abnormality detection process. However, as a representative example of these voltage detection lines, the first voltage detection line 21 will be used as the subject of connection abnormality detection.

[0281] For example, by sequentially performing the sixth abnormality detection process on each voltage detection line included in the voltage detection line group 20 , connection abnormalities can be detected for all the voltage detection lines included in the voltage detection line group 20 .

[0282] Figure 15 This is a flowchart of the sixth abnormality detection process.

[0283] The sixth abnormality detection process is executed when specified conditions are met (for example, a specified time has passed since the voltage detection circuit 1450 was started, a specified time has passed since the last time the sixth abnormality detection process was executed, a user using the voltage detection circuit 1450 has performed a specified operation on the voltage detection circuit 1450, etc.).

[0284] At the beginning of the sixth abnormality detection process, the abnormality judgment circuit 60 turns on the lead-out constant current source of the first current generating circuit 71, which is a current generating circuit connected to the voltage detection line that is the detection object of the connection abnormality, namely the first voltage detection line 21 (step S1510).

[0285] The abnormality determination circuit 60 then controls the selection states of the first multiplexer 1491 and the second multiplexer 1492, causing the multiplexer 90 to select a pair of voltages consisting of the voltage at the first terminal 51 and the voltage at the second terminal 52. Furthermore, the abnormality determination circuit 60 controls the comparator 1481, causing the voltage detector 1480 to detect the difference between the voltage at the second terminal 52 (voltage Vm detected by the primary monitoring system) and the voltage at the first terminal 51 (voltage Vs detected by the secondary monitoring system) (step S1515).

[0286] When the difference (Vm-Vs) between the voltage Vm of the second terminal 52 and the voltage Vs of the first terminal 51 is detected, the abnormality judgment circuit 60 judges whether the value of Vm-Vs is less than a predetermined abnormality judgment value (threshold) Vth (for example, 0.5V) (step S1520).

[0287] In the process of step S1520 , when the value of Vm-Vs is less than or equal to Vth (step S1520 : Yes), the abnormality determination circuit 60 determines that there is a connection abnormality in the first voltage detection line 21 (step S1525 ).

[0288] In the process of step S1520 , if the value of Vm-Vs is not less than Vth (step S1520 : No), the abnormality determination circuit 60 determines that there is no connection abnormality in the first voltage detection line 21 (step S1530 ).

[0289] When the process of step S1525 is completed or when the process of step S1530 is completed, the abnormality determination circuit 60 turns off the constant current source for extraction of the first current generating circuit 71 (step S1535 ).

[0290] When the process of step S1535 is completed, the voltage detection circuit 1450 ends the sixth abnormality detection process.

[0291] The following describes in detail the determination of whether or not there is a connection abnormality by the abnormality determination circuit 60 in the processing from “No” in step S1510 to step S1535 using the accompanying drawings.

[0292] Figure 16A The schematic diagram shows the transition of the voltage Vm detected by the main monitoring system, the transition of the voltage Vs detected by the auxiliary monitoring system, and the transition of Vm-Vs when the first voltage detection line 21 does not have a connection abnormality due to a break.

[0293] Figure 16B The schematic diagram shows the transition of the voltage Vm detected by the main monitoring system, the transition of the voltage Vs detected by the auxiliary monitoring system, and the transition of Vm-Vs when a connection abnormality due to disconnection occurs in the first voltage detection line 21.

[0294] (a) When the first voltage detection line 21 does not have a connection abnormality due to disconnection (see Figure 16A ), the voltage Vm detected by the main monitoring system remains at the anode potential of the first battery 11, that is, 7.4V, even when the constant current source for extraction of the first current generating circuit 571 is turned on at time t10. In contrast, the voltage Vs detected by the auxiliary monitoring system, when the constant current source for extraction of the first current generating circuit 571 is turned on at time t10, becomes the value obtained by subtracting the voltage (1V (=1KΩ×1mA)) generated by the constant current (1mA) flowing into the first resistor 41 (1KΩ) from the anode potential of the battery 11 (7.4V), that is, 6.4V. Therefore, the value Vm-Vs detected at time t15 becomes 1V.

[0295] Furthermore, (b) when a connection abnormality occurs in the first voltage detection line 21 due to a disconnection (see Figure 16B ). When the constant current source for extraction of the first current generating circuit 571 is turned on at time t10, the first terminal 51 is disconnected from the anode of the first battery 11 and enters a high-impedance state. Therefore, the voltage at the first terminal 51 decreases until the constant current source for extraction of the first current generating circuit 571 stops extracting current (here, for example, to 0V). Consequently, the voltage Vs detected by the auxiliary monitoring system decreases to 0V. The same applies to the second terminal 52. Since it is disconnected from the anode of the first battery 11 and enters a high-impedance state, the voltage at the second terminal 52 decreases until the constant current source for extraction of the first current generating circuit 571 stops extracting current (here, for example, to 0V). Consequently, the voltage Vs detected by the main monitoring system also decreases to 0V. Consequently, the Vm-Vs detected at time t15 becomes 0V.

[0296] By setting the abnormality determination value Vth to, for example, 0.5 V in this manner, it is possible to detect whether or not there is a connection abnormality due to a disconnection.

[0297] Since the value of Vm-Vs varies depending on the constant of the filter circuit and the current value of the constant current source, the abnormality determination value Vth may be set to meet these conditions.

[0298] [6-3. Effects, etc.]

[0299] The battery system 6 described above can achieve the same effects as those of the battery system 1 in the first embodiment.

[0300] (Replenish)

[0301] As described above, as examples of the technology disclosed in this application, embodiments 1 to 6 have been described. However, the technology in this application is not limited thereto, and embodiments obtained by appropriately changing, replacing, adding, or omitting the same can also be applied.

[0302] (1) In the examples described in Embodiments 1 to 5, the main monitoring system is composed of a multiplexer and an AD converter (for example, the first multiplexer 91 and the first AD converter 81 in Embodiment 1), and the auxiliary monitoring system is composed of a multiplexer and an AD converter (for example, the second multiplexer 92 and the second AD converter 82 in Embodiment 1).

[0303] Figure 17A In the example shown in the block diagram of , the main monitoring system is composed of a multiplexer and an AD converter, and the auxiliary monitoring system is composed of a multiplexer and an AD converter.

[0304] However, the present invention is not limited thereto, and the main monitoring system and the auxiliary monitoring system are not limited to being composed of one multiplexer and one AD converter respectively. Figure 17B An example is shown in which the main monitoring system is composed of multiple multiplexers and multiple AD converters. Figure 17C Examples are shown in which the main monitoring system and the auxiliary monitoring system are each composed of multiple multiplexers and multiple AD converters. Furthermore, the number of voltages detected by the main monitoring system and the number of voltages detected by the auxiliary monitoring system are not necessarily the same. Furthermore, the main monitoring system and the auxiliary monitoring system may not include multiplexers, but may instead include an AD converter for each voltage to be detected.

[0305] (2) In the example described in Implementation 6, the main monitoring system is composed of a multiplexer (first multiplexer 1491), the auxiliary monitoring system is composed of a multiplexer (second multiplexer 1492), and the voltage detector is composed of a comparator (comparator 1481).

[0306] Figure 18A The block diagram of FIG. 1 shows an example in which the main monitoring system is composed of a multiplexer, the auxiliary monitoring system is composed of a multiplexer, and the voltage detector is composed of a comparator.

[0307] However, the present invention is not limited to this configuration, and the main monitoring system and the auxiliary monitoring system are not limited to being respectively configured by a multiplexer, and the voltage detector is not limited to being configured by a comparator. For example, Figure 18B In the example shown, the main monitoring system and the auxiliary monitoring system can each be composed of multiple multiplexers, and the voltage detector can be composed of multiple comparators. Figure 18C In the example shown, the main monitoring system and the auxiliary monitoring system may not include a multiplexer, but may be configured such that comparators are provided between terminals to be compared.

[0308] (3) In the examples described in Embodiments 1 to 6, the abnormality detection device includes a filter circuit, a voltage detection circuit, and an abnormality determination circuit.

[0309] However, the abnormality determination device is not limited to the above configuration.

[0310] Figure 19 The block diagram shows an example in which the abnormality determination device includes a plurality of units (battery monitoring ICs, etc.), each of which includes a filter circuit and a voltage detection circuit for a plurality of batteries.

[0311] As an example, consider that the anomaly detection device is Figure 19In this case, for example, the units are connected to each other in a manner capable of communicating with each other, and the abnormality determination circuit may be connected to one unit in a manner capable of communicating with each other, and may communicate with the other units in a daisy-chain manner.

[0312] (4) Furthermore, the following embodiments can be considered.

[0313] (4-1. Implementation Method 7)

[0314] The battery module management system involved in this embodiment includes: a battery pack, which is composed of a plurality of battery cells connected in series; a detection terminal, which is respectively connected to two terminals of the plurality of battery cells; an abnormality detection circuit, which detects abnormalities in the battery cell voltage; and a functional unit that allows current to flow into or out of the battery cell via a connecting line. The abnormality detection circuit is provided with two systems (called a main system and an auxiliary system) that monitor the voltage of the same battery cell. By comparing the voltage values ​​of the main system and the auxiliary system in a state where current is introduced from the battery cell or in a state where current is allowed to flow out of the functional unit, a disconnection is detected.

[0315] Figure 20A 、 Figure 20B 、 Figure 20C Each of them is a configuration diagram of the power storage module management system according to the seventh embodiment. Figure 20A 、 Figure 20B 、 Figure 20C Among them, the system that uses C0 to C10 to perform abnormality judgment is the main monitoring system, and the system that uses CB0 to CB10 to perform abnormality judgment is the auxiliary monitoring system.

[0316] The following are conceivable functional units that allow current to flow into and out of the battery cells.

[0317] (1-1) Circuit that short-circuits the detection terminals ( Figure 20A 、 20B )

[0318] (1-2) A circuit that short-circuits the detection terminal at an arbitrary potential. (The arbitrary potential is, for example, GND potential, internally generated voltage, etc.)

[0319] Furthermore, in (1-1) and (1-2), the short circuit need not be a complete short circuit; a resistor element may be present. The short circuit can occur not only between adjacent detection terminals but also between any terminals. The circuit can also function as a balancing circuit for equalizing battery cell voltages.

[0320] (1-3) Constant current circuit for introducing or discharging constant current ( Figure 20C )

[0321] (1-4) The above (1-1) to (1-3) can be executed only on a specific battery cell or simultaneously on multiple battery cells.

[0322] The abnormality detection circuit is shown below.

[0323] (1-5) AD converter that converts battery cell voltage into digital signal ( Figure 20A )

[0324] (1-6) A comparator that compares the battery cell voltage with a specified voltage ( Figure 20B )

[0325] The configuration of a comparator or AD converter is as follows.

[0326] (1-7) A comparator or an AD converter is mounted on each battery cell.

[0327] (1-8) The comparator or AD converter is shared by multiple battery cells, and the battery cell voltages are sequentially selected by a multiplexer and input to the circuit.

[0328] [Other inventions]

[0329] For the battery cell that detects disconnection by flowing current in and out, and the battery cells above and below it, the voltage input to the abnormality detection circuit fluctuates from its original voltage. Therefore, when detecting abnormality in the battery cell voltage, a predetermined amount of time is required for the input voltage to return to its original value after the current flow stops.

[0330] When abnormality detection is performed after current is flowing in or out, time can be saved by first performing detection on a battery cell different from the battery cell that has flowed in or out the current.

[0331] For example, for voltage abnormality detection of a battery pack in which the number of all battery cells is 10 battery cells, when the detection is performed by a comparator or an AD converter in the above-mentioned (1-8) configuration (the battery cell voltage is selected in sequence by a multiplexer), the battery cell voltage is usually measured in the order of battery cell E1 → battery cell E2 → ... battery cell E9 → battery cell E10.

[0332] However, when the disconnection detection of battery cell E1 is performed, the subsequent battery cell voltage abnormality detection is performed in the order of battery cell E3 → battery cell E4 → ... battery cell E9 → battery cell E10 → battery cell E1 → battery cell E2, so as to ensure the recovery time of the voltage of battery cell 1.

[0333] Furthermore, it is preferable that the measurements of the main system and the auxiliary system be performed at the same timing (if the timings are different, accurate comparison cannot be made if the input voltage fluctuates during the measurement).

[0334] Furthermore, when a constant current circuit is used as a function to direct current into and out of the battery cells, if only one of these two modes is active, the current consumed by each battery cell becomes unbalanced. Therefore, by alternating between current flow and current flow, the average current between the battery cell and the input terminal is brought close to zero, thus ensuring that the current consumed by the battery cells is evenly distributed.

[0335] Regarding the disconnection detection method, we will use Figure 21A as well as Figure 21B To explain.

[0336] The auxiliary monitoring system's input terminals are connected via connecting wires to a circuit that draws current from or drains current from the battery cells. A resistor element, acting as a filter, is placed between the battery cells and the input terminals. When current is input, the resulting voltage fluctuations across the battery cells are fed into the auxiliary monitoring system.

[0337] When comparing the voltage values ​​of the main and auxiliary systems while current is flowing, a voltage difference of at least a specified value will occur between the main and auxiliary monitoring systems if the line is intact. In the event of a line break, the voltage of the main monitoring system fluctuates due to the influence of the auxiliary monitoring system, resulting in a smaller potential difference than in the intact state.

[0338] An example of a disconnection detection sequence (when the connection line: H1 is disconnected) is described.

[0339] (A) Measure the battery cell voltages of the main monitoring system and the auxiliary monitoring system.

[0340] (B) The short-circuit switch of the battery unit 1 is switched from OFF to ON.

[0341] (C) The battery cell voltages of the main monitoring system and the auxiliary monitoring system are measured.

[0342] (D) When the voltage difference between the AD converters of the main monitoring system and the auxiliary monitoring system is within 1.0 V, it is determined that there is a line break.

[0343] The present invention can be widely applied to a system for detecting the voltage of a battery.

Claims

1. A voltage detection circuit, wherein: The battery comprises: a first terminal connected to the other end of a first voltage detection line connected to a first electrode at one end thereof via a first resistor, the first electrode being either an anode or a cathode of a first battery; a second terminal, configured to be connected to the other end of the first voltage detection line without passing through the first resistor; a first current generating circuit connected to the first terminal; and a voltage detector for detecting the voltage of the first terminal and the voltage of the second terminal, the voltage detector having at least one first AD converter connected to the first terminal and at least one second AD converter connected to the second terminal, and performing the voltage detection by the first AD converter and the voltage detection by the second AD converter substantially simultaneously, the first AD converter detecting the voltage of the first terminal and outputting the detected voltage of the first terminal, the second AD converter detecting the voltage of the second terminal and outputting the detected voltage of the second terminal, the first current generating circuit alternately drawing a constant current from the first terminal and flowing a constant current into the first terminal during the period when the first AD converter and the second AD converter perform detection, thereby generating a potential difference between the first terminal and the second terminal.

2. The voltage detection circuit according to claim 1, wherein: The voltage detector performs detection of the voltage by the first AD converter and detection of the voltage by the second AD converter within 1 ms.

3. The voltage detection circuit according to claim 1 or 2, wherein: The voltage detector outputs a voltage of the first AD converter and a voltage of the second AD converter.

4. The voltage detection circuit according to claim 1 or 2, wherein: The voltage detector converts a voltage of the first terminal and a voltage of the second terminal into digital values.

5. The voltage detection circuit according to claim 1 or 2, wherein: The first current generating circuit includes a first constant current source that draws current from the first terminal and a second constant current source that flows current into the first terminal.

6. The voltage detection circuit according to claim 1 or 2, wherein: The first current generating circuit includes a first constant current source connected between the first terminal and the power supply potential of the voltage detecting circuit and configured to flow current.

7. The voltage detection circuit according to claim 1 or 2, wherein: The first current generating circuit includes a second constant current source connected between the first terminal and the ground potential of the voltage detecting circuit to draw current.

8. The voltage detection circuit according to claim 1 or 2, wherein: The voltage detector includes a comparator that outputs a difference between a voltage at the first terminal and a voltage at the second terminal.

9. The voltage detection circuit according to claim 3, wherein: The voltage detection circuit includes: a third terminal connected to the other end of a second voltage detection line having one end connected to a second electrode via a second resistor, the second electrode being one of an anode and a cathode of a second battery connected in series with the anode side of the first battery; and a fourth terminal connected to the other end of the second voltage detection line without passing through the second resistor, wherein the voltage detector detects a difference between a voltage at the third terminal and a voltage at the fourth terminal.

10. The voltage detection circuit according to claim 9, wherein: The voltage detection circuit further includes a second current generating circuit connected to the third terminal. The second current generating circuit includes a switch that draws current from the first terminal or flows current into the third terminal by short-circuiting the anode and cathode of the second battery via the second resistor.

11. The voltage detection circuit according to claim 9, wherein: The voltage detector includes a comparator that detects a difference between a voltage of the third terminal and a voltage of the fourth terminal.

12. The voltage detection circuit according to claim 9, wherein: The voltage detection circuit includes a multiplexer that selectively transmits a pair of voltages consisting of the voltage at the first terminal and the voltage at the second terminal, and one of a pair of voltages consisting of the voltage at the third terminal and the voltage at the fourth terminal to the voltage detector. The voltage detector performs the detection by detecting a difference between the pair of voltages selectively transmitted by the multiplexer.

13. The voltage detection circuit according to claim 9, wherein: The voltage detection circuit includes a multiplexer that selectively transmits one of a plurality of pairs of voltages, including a pair of voltages consisting of the voltage at the first terminal and the voltage at the second terminal, and a pair of voltages consisting of the voltage at the third terminal and the voltage at the fourth terminal, to the voltage detector. The voltage detector performs the detection by detecting a difference between the pair of voltages selectively transmitted by the multiplexer.

14. The voltage detection circuit according to claim 1 or 2, wherein: The first current generating circuit includes a switch that draws current from the first terminal or flows current into the first terminal by short-circuiting the anode and cathode of the first battery via the first resistor.

15. An abnormality detection device, wherein: The device comprises: the voltage detection circuit according to any one of claims 1 to 14; the first resistor; a fifth terminal connected to the other end of the first voltage detection line; and a first connection path connecting the first terminal and the fifth terminal via the first resistor. a second connection path connecting the second terminal and the fifth terminal without passing through the first resistor; and an abnormality determination circuit that detects a connection abnormality of the first voltage detection line based on the voltage of the first terminal and the voltage of the second terminal.

16. The abnormality detection device according to claim 15, wherein: The abnormality determination circuit detects a difference between a voltage at the first terminal and a voltage at the second terminal.

17. The abnormality detection device according to claim 15 or 16, wherein: The abnormality determination circuit performs abnormality detection by allowing a predetermined time after the outflow of current or the introduction of current stops until the voltage input to the abnormality detection device returns to a normal battery cell voltage value.

18. The abnormality detection device according to claim 15 or 16, wherein: The abnormality determination circuit sequentially determines abnormalities of other batteries after determining abnormalities of one battery, and determines abnormalities of the one battery after determining abnormalities of all other batteries.

19. The abnormality detection device according to claim 15 or 16, wherein: The voltage detection circuit has a second voltage detection line with one end connected to a second electrode, and the second electrode is one of the anode and cathode of the second battery connected in series with the anode side of the first battery. The abnormality judgment circuit performs abnormality judgment on the first voltage detection line and the second voltage detection line at the same time.

20. The abnormality detection device according to claim 15 or 16, wherein: The abnormality determination circuit draws current into the fifth terminal and then causes the current to flow out, and then performs abnormality determination.

21. A battery system, wherein: The device comprises: the abnormality detection device according to any one of claims 15 to 20; the first battery; and the first voltage detection line, wherein one end of the first voltage detection line is connected to the first electrode and the other end of the first voltage detection line is connected to the fifth terminal.

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