Disconnection detection device and battery monitoring device

Abstract

The purpose of the present invention is to provide a disconnection detection device and a battery monitoring device capable of normally detecting disconnection of wiring on the basis of a cell voltage, even when each of the wiring is provided with a CR low-pass filter and an electronic switch of a discharge circuit is provided with a protection function. In the present invention, a disconnection detection device is provided with: a voltage detection circuit for detecting the cell voltage of a battery provided with a plurality of battery cells connected in series to each other and each connected in parallel to a discharge circuit provided with an electronic switch; a CR low-pass filter provided in each of a plurality of wirings connecting the battery cell and the voltage detection circuit; and a control unit that causes the discharge circuit to discharge in an equalized manner and detects disconnection of the wiring on the basis of the cell voltage, in the disconnection detection device, the electronic switch has a protection function that prohibits transition to an ON state. The control unit removes the charge accumulated in the CR low-pass filter by operating one of the pair of electronic switches associated with the pair of battery cells adjacent to each other, and detects the disconnection of the wiring on the basis of the cell voltage after the removal of the charge.

Description

Technical Field

[0001] The present invention relates to a disconnection detection device and a battery monitoring device. Background Art

[0002] The following Patent Document 1 discloses a cell balance control device. The cell balance control device is composed of a series circuit of a bypass resistor and a switch element, and includes: a discharge circuit connected in parallel to each of a plurality of battery cells constituting a battery; a voltage detection circuit detecting the voltage of each of the battery cells; and a control unit controlling each switch element so that the voltage of each battery cell becomes uniform based on the voltage detection result of each battery cell obtained from the voltage detection circuit, controlling the switch elements of the discharge circuit connected to adjacent battery cells with different duty ratios, and detecting the disconnection of wiring drawn from both ends of each battery cell based on the potential difference between adjacent battery cells.

[0003] In addition to such wire break detection, the cell balance control device balances (equalizes) the charge amounts of a plurality of battery cells by forcibly discharging the battery cells using a discharge circuit. That is, when the cell voltage of an adjacent battery cell is higher than the cell voltage of a certain battery cell, the cell balance control device equalizes the charge amounts of the battery cells by forcibly discharging (equalizing discharge) using a discharge circuit connected to the adjacent battery cells.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2013-085354 Summary of the invention

[0007] Problems to be solved by the invention

[0008] However, although not described in Patent Document 1, some cell balance control devices include a CR (capacitance resistance) low-pass filter in each wiring. The CR low-pass filter is an additional circuit for removing noise intruding into the wiring and detecting the cell voltage more accurately, and is provided in each wiring at a portion closer to the voltage detection circuit than the discharge circuit.

[0009] In addition, some cell balance control devices are equipped with a protection function to prevent overcurrent from flowing through the switch element (electronic switch) of the discharge circuit. If such a protection function is provided, if a wiring break occurs, a voltage twice the normal voltage may be applied to the electronic switch.

[0010] In such a case where a CR low-pass filter is provided in each wiring and a protection function is provided in the electronic switch of the discharge circuit, if a wire break occurs in the wiring on the low potential side connected to a certain battery cell during the equalization discharge of the certain battery cell, the capacitor of the CR low-pass filter provided in the wiring on the low potential side is charged with a voltage twice the voltage normally applied.

[0011] However, since the protection function operates based on the double voltage, the electronic switch connected to the discharge circuit of the capacitor cannot be switched to the ON state, and the charge of the capacitor cannot be discharged. If the capacitor remains in the charged state, it becomes impossible to perform normal detection of disconnection based on the cell voltage.

[0012] The present invention is completed in view of the above situation, and its purpose is to provide a disconnection detection device and a battery monitoring device that can normally detect disconnection of wiring based on the cell voltage even when each wiring has a CR low-pass filter and the electronic switch of the discharge circuit has a protection function.

[0013] Means for solving problems

[0014] The first mode of the disconnection detection device in the present disclosure comprises: a voltage detection circuit, for detecting the cell voltage of a battery having a plurality of battery cells, wherein the plurality of battery cells are connected in series with each other and are respectively connected in parallel with a discharge circuit having an electronic switch; a CR low-pass filter, provided at each of a plurality of wirings connecting the battery cells and the voltage detection circuit; and a control unit, for making the discharge circuit discharge uniformly and detecting the disconnection of the wiring based on the cell voltage, wherein in the disconnection detection device, the electronic switch has a protection function of prohibiting migration to an on state, and the control unit removes the charge accumulated in the CR low-pass filter by operating one of a pair of electronic switches associated with a pair of adjacent battery cells, and detects the disconnection of the wiring based on the cell voltage after the removal of charge.

[0015] In the second mode of the wire break detection device disclosed in the present invention, when the control unit determines that the protection function of the electronic switch pre-set as the de-static switch of the CR low-pass filter is operating, the control unit de-staticizes the CR low-pass filter by setting the electronic switch paired with the electronic switch that has operated the protection function to an on state.

[0016] In the disconnection detection device of the third aspect of the present disclosure, the control unit recognizes disconnection of the wiring and abnormality of the battery cell based on a difference voltage and a sum voltage between cell voltages of a pair of the battery cells when at least one of the discharge circuits is discharged.

[0017] In the wire breakage detection device according to a fourth aspect of the present disclosure, the discharge circuit is a series circuit of the electronic switch and a resistor.

[0018] A battery monitoring device according to a first aspect of the present disclosure includes the disconnection detection device according to any one of the first to fourth aspects, and controls the connection between the battery and the load based on a disconnection detection result of the disconnection detection device.

[0019] Effects of the Invention

[0020] According to the present disclosure, a disconnection detection device and a battery monitoring device can be provided that can normally detect disconnection of a wiring based on a cell voltage even when each wiring has a CR low-pass filter and an electronic switch of a discharge circuit has a protection function. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 1 is a block diagram showing the structure of a battery monitoring device A according to an embodiment of the present disclosure.

[0022] Figure 2 1 is a flowchart showing the operation of the battery monitoring device A according to the embodiment of the present disclosure.

[0023] Figure 3 It is a timing chart showing the operation of the battery monitoring device A according to the embodiment of the present disclosure.

[0024] Figure 4 1 is a first circuit diagram showing the operation of the battery monitoring device A according to the embodiment of the present disclosure.

[0025] Figure 5A 1 is a first characteristic diagram showing the operation of the battery monitoring device A according to the embodiment of the present disclosure.

[0026] Figure 5B 2 is a second characteristic diagram showing the operation of the battery monitoring device A according to the embodiment of the present disclosure. DETAILED DESCRIPTION

[0027] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

[0028] First, refer to Figure 1 The functional structure of the battery monitoring device A according to the present embodiment will be described.

[0029] The battery monitoring device A is mounted on an electric vehicle such as an electric car or a hybrid car, and monitors a battery B such as a lithium-ion battery or a fuel cell. The battery monitoring device A controls the connection between the battery B and the load based on the monitoring result of the battery B (disconnection detection result).

[0030] exist Figure 1 In FIG. 1 , a pair of battery cells B adjacent to each other are simply shown. n , B n+1 , but battery B is actually a plurality of (n+1) battery cells B1, ..., B n , B n+1 The battery B is connected in series with the first to the n+1th battery cells B1 to B n+1 The output voltage of the first to n+1th battery cells V1 to V n+1 The voltage after the sum is taken as the battery voltage. In addition, the above n is an arbitrary natural number.

[0031] The first to n+1th battery cells B1 to B n+1 As shown in the figure, each electrode is connected by a plurality of (n+1) wirings VH1, ..., VH n , VH n+1 Connected to the input terminals T1, ..., T n , T n+1 For example, the nth battery cell B n The negative electrode of n-1 Connected to the n-1th input terminal T of the battery monitoring device A n-1 That is, the first wiring VH n-1 One end is connected to the nth battery cell B n The negative electrode of the battery monitoring device A is connected to the n-1th input terminal T n-1 .

[0032] The nth battery cell B n The positive electrode and the n+1th battery cell B n+1 The negative electrode of n Connected to the nth input terminal T of the battery monitoring device A n That is, the nth wiring VH n One end is connected to the nth battery cell B n The positive electrode and the n+1th battery cell B n+1 The negative electrode of the battery monitoring device A is connected to the nth input terminal T n .

[0033] Battery Cell B n+1 The positive electrode ofn+1 Connected to the n+1th input terminal T of the battery monitoring device A n+1 That is, the n+1th wiring VH n+1 One end is connected to the n+1th battery cell B n+1 The positive electrode of the battery monitoring device A is connected to the n+1th input terminal T n+1 .

[0034] That is, the battery monitoring device A according to the present embodiment is connected to the battery via (n+1) wiring lines VH1, . . . , VH n , VH n+1 is connected to the battery B. If the first to n+1th wiring lines VH1 to VH n+1 If any of the battery cells B1 to B2 is disconnected, the battery monitoring device A cannot correctly detect the first to n+1th battery cells B1 to B3 in the battery B. n+1 The inter-electrode voltage is the voltage of the first to n+1 cells V1 to V n+1 , normal monitoring of battery B cannot be implemented.

[0035] In view of this situation, the battery monitoring device A includes a detection circuit for detecting the first to n+1th wiring lines VH1 to VH2. n+1 Although the details will be described later, the battery monitoring device A according to the present embodiment is based on the first to n+1th cell voltages V1 to V n+1 To detect the first to n+1th wiring lines VH1 to VH n+1 A wire breakage detection device for detecting a wire breakage of any one of the wire breaks.

[0036] The battery monitoring device A is shown in the figure. In addition to the first to n+1th input terminals T1 to T n+1 In addition, there are (n+1) first resistors R11 to R1 n+1 , (n+1) second resistors R21-R2 n+1 , (n+1) third resistors R31-R3 n+1 , (n+1) first capacitors C11-C1 n+1 , (n+1) second capacitors C21-C2 n+1 、(n+1) electronic switches D1~D n+1 、(n+1) differential amplifiers E1~E n+1 、(n+1) control circuits F1~F n+1 、(n+1) voltage amplifiers G1~G n+1 , and MPU 1.

[0037] The first to n+1th input terminals T1 to T n+1 The n-1th input terminal T n-1As shown in the figure, it is connected to the n-1th wiring VH n-1 The other end of the second resistor R2 n and a third resistor R3 n The nth input terminal T n are connected to the nth wiring VH n The other end of the first resistor R1 n One end of the second resistor R2 n and a third resistor R3 n+1 The n+1th input terminal T n+1 are respectively connected to the first resistor R1 n+1 and a second resistor R2 n+1 one end.

[0038] (n+1) first resistors R11-R1 n+1 , (n+1) second resistors R21-R2 n+1 , (n+1) third resistors R31-R3 n+1 The first resistor R1 in n-1 One end is connected to the n-1th input terminal T n-1 , and a third resistor R3 n One end of the first resistor R1 n-1 The other end is connected to the first capacitor C1 n-1 One end of the nth voltage amplifier G n The input terminal of one side.

[0039] The first resistor R1 n One end is connected to the nth input terminal T n , the second resistor R2 n and the first resistor R1 n+1 One end of the first resistor R1 n The other end is connected to the first capacitor C1 n One end of the nth voltage amplifier G n The other input terminal of the n+1th voltage amplifier G n+1 The input terminal of one side.

[0040] The second resistor R2 n One end is connected to the nth input terminal T n , the first resistor R1 n and a third resistor R3 n+1 One end of the second resistor R2 n The other end is connected to the nth electronic switch D n One end of the second capacitor C2 n One end of the nth differential amplifier En The input terminal of one side.

[0041] The third resistor R3 n One end is connected to the n-1th input terminal T n-1 , and a first resistor R1 n-1 One end of the third resistor R3 n The other end of the second capacitor C2 is connected to the other end of the nth electronic switch Dn and the n The other end of the nth differential amplifier E n The other input terminal.

[0042] The first resistor R1 n+1 One end is connected to the n+1th input terminal T n+1 , and a second resistor R2 n+1 One end of the first resistor R1 n+1 The other end is connected to the first capacitor C1 n+1 One end of the n+1th voltage amplifier G n+1 The other input terminal.

[0043] The second resistor R2 n+1 One end is connected to the n+1th input terminal T n+1 , and a first resistor R1 n+1 One end of the second resistor R2 n+1 The other end is connected to the n+1th electronic switch D n+1 One end of the second capacitor C2 n+1 One end of the (n+1) differential amplifier E n+1 The input terminal of one side.

[0044] The third resistor R3 n+1 One end is connected to the nth input terminal T n , the first resistor R1 n and a second resistor R2 n One end of the third resistor R3 n+1 The other end is connected to the n+1th electronic switch D n+1 The other end of the second capacitor C2 n+1 The other end of the (n+1) differential amplifier E n+1 The other input terminal.

[0045] (n+1) first capacitors C11-C1 n+1 , (n+1) second capacitors C21-C2 n+1 The first capacitor C1 n-1 One end of the resistor R1 is connected to the n-1 The other end of the nth voltage amplifier Gn The first capacitor C1 is n-1 The other end of the first capacitor C1 is grounded. n-1 and the first resistor R1 n-1 It constitutes the n-1th CR low-pass filter.

[0046] The second capacitor C1 n One end of the resistor R1 is connected to the n The other end of the nth voltage amplifier G n The input terminal of one of the n+1 voltage amplifiers G n+1 The first capacitor C1 is n The other end of the first capacitor C1 is grounded. n and the first resistor R1 n The nth CR low-pass filter is formed.

[0047] The third capacitor C2 n One end of the resistor R2 is connected to the n The other end of the nth electronic switch D n One end of the nth differential amplifier E n The second capacitor C2 is n The other end is connected to the third resistor R3 n The other end of the nth electronic switch D n The other end of the nth differential amplifier E n The other input terminal.

[0048] The first capacitor C1 n+1 One end of the resistor R1 is connected to the n+1 The other end of the n+1th voltage amplifier G n+1 The other input terminal of the first capacitor C1 n+1 The other end of the first capacitor C1 is grounded. n+1 and the first resistor R1 n+1 This constitutes the n+1th CR low-pass filter.

[0049] The second capacitor C2 n+1 One end of the resistor R2 is connected to the n+1 The other end of the n+1th electronic switch D n+1 One end of the (n+1) differential amplifier E n+1 The second capacitor C2 is n+1 The other end is connected to the third resistor R3 n+1 The other end of the n+1th electronic switch D n+1 The other end of the (n+1) differential amplifier En+1 The other input terminal.

[0050] (n+1) electronic switches D1~D n+1 The nth electronic switch D in n One end of the resistor R2 is connected to the n The other end of the second capacitor C2 n One end of the nth differential amplifier E n The input terminal of one side, the nth electronic switch D n The other end is connected to the third resistor R3 n The other end of the second capacitor C2 n The other end of the nth differential amplifier E n The other input terminal.

[0051] At the nth electronic switch D n A pair of input terminals is provided in the nth electronic switch D n One of the pair of input terminals in the n-th control circuit F is connected to the n-th control circuit F n The output terminal of the MPU 1 is connected to one of a pair of output terminals of the MPU 1, and the input terminal of the MPU 1 is connected to one of a pair of output terminals of the MPU 1.

[0052] The n+1th electronic switch D n+1 One end of the resistor R2 is connected to the n+1 The other end of the second capacitor C2 n+1 One end of the (n+1) differential amplifier E n+1 The input terminal of one side, the n+1th electronic switch D n+1 The other end is connected to the third resistor R3 n+1 The other end of the second capacitor C2 n+1 The other end of the (n+1) differential amplifier E n+1 The other input terminal.

[0053] At the n+1th electronic switch D n+1 A pair of input terminals is provided in the n+1th electronic switch D n+1 One of the pair of input terminals in the input circuit is connected to the n+1th control circuit F n+1 The output terminal of the nth electronic switch D is connected to the other output terminal of the MPU 1. n and the n+1th electronic switch D n+1 They are adjacent to each other and are paired electronic switches.

[0054] Here, the second resistor R2 n , the third resistor R3 n and the nth electronic switch D nThe nth series circuit is connected to the nth battery cell B n The nth discharge circuit connected in parallel. That is, if the nth electronic switch D n is set to the ON state, the nth discharge circuit connects the second resistor R2 n and the third resistor R3 n As a discharge resistor, the nth battery cell B is charged n The charge in the battery is forced to discharge.

[0055] In addition, the second resistor R2 n+1 , the third resistor R3 n+1 and the n+1th electronic switch D n+1 The n+1th series circuit is connected to the n+1th battery cell B. n+1 The n+1th discharge circuit connected in parallel. That is, if the n+1th electronic switch D n+1 is set to the ON state, the n+1th discharge circuit connects the second resistor R2 n+1 , the third resistor R3 n+1 As a discharge resistor, the battery cell B charged to the n+1th battery cell n+1 The charge in the battery is forced to discharge.

[0056] (n+1) differential amplifiers E1~E n+1 The nth differential amplifier E in n The input terminal of one side is connected to the second resistor R2 n The other end of the nth electronic switch D n and a second capacitor C2 n One end of the nth differential amplifier E n The other input terminal is connected to the third resistor R3 n The other end of the nth electronic switch D n The other end of the second capacitor C2 n The other end of the nth differential amplifier E n The output terminal is connected to the nth differential amplifier E n The input terminal.

[0057] That is, the nth differential amplifier E n For the nth electronic switch D n The nth differential amplifier E n The above-mentioned inter-terminal voltage is output as the nth detection voltage to the nth control circuit F n .

[0058] The n+1th differential amplifier E n+1The input terminal of one side is connected to the second resistor R2 n+1 The other end of the n+1th electronic switch D n+1 and a second capacitor C2 n+1 One end of the n+1th differential amplifier E n+1 The other input terminal is connected to the third resistor R3 n+1 The other end of the n+1th electronic switch D n+1 The other end of the second capacitor C2 n+1 The other end of the n+1th differential amplifier E n+1 The output end is connected to the n+1th differential amplifier E n+1 The input terminal.

[0059] The n+1th differential amplifier E n+1 For the n+1th electronic switch D n+1 The voltage between the terminals is amplified. The n+1th differential amplifier E n+1 The above-mentioned inter-terminal voltage is output as the n+1th detection voltage to the n+1th control circuit F n+1 .

[0060] (n+1) control circuits F1~F n+1 The nth control circuit F in n The input end is connected to the nth differential amplifier E n The output terminal of the nth control circuit F n The output end is connected to the nth electronic switch D n The nth control circuit F n Based on the nth differential amplifier E n The nth detection voltage is input to control the nth electronic switch D n The open / closed state in.

[0061] The n+1th control circuit F n+1 The input end is connected to the n+1th differential amplifier E n+1 The output terminal of the n+1th control circuit F n+1 The output end is connected to the n+1th electronic switch D n+1 The input terminal of one of the n+1 control circuits F n+1 Based on the n+1th differential amplifier E n+1 The input n+1th detection voltage controls the n+1th electronic switch D n+1 The open / closed state in.

[0062] Here, (n+1) differential amplifiers E1 to E n+1 and (n+1) control circuits F1 to F n+1The first to n+1th electronic switches D1 to D n+1 The structural elements attached to each other. For the nth electronic switch D n The nth differential amplifier E is provided n and the nth control circuit F n , for the n+1th electronic switch D n+1 The n+1th differential amplifier E is provided n+1 and the n+1th control circuit F n+1 .

[0063] That is, the nth electronic switch D n Based on the nth differential amplifier E n and the nth control circuit F n The nth overcurrent protection function, the n+1th electronic switch D n+1 The n+1th differential amplifier E n+1 and the n+1th control circuit F n+1 The n+1th overcurrent protection function.

[0064] If the nth electronic switch D n If an overvoltage is applied between one end and the other end, that is, between the terminals, the nth overcurrent protection function prohibits the nth electronic switch D n to the ON state, so that the nth electronic switch D n No overcurrent flows through the n+1th electronic switch D n+1 If an overvoltage is applied between one end and the other end, that is, between the terminals, the n+1th overcurrent protection function prohibits the n+1th electronic switch D n+1 The n+1th electronic switch D n+1 No overcurrent flows.

[0065] (n+1) voltage amplifiers G1~G n+1 It is to detect (calculate) the first to n+1th battery cells B1 to B n+1 The voltages of the first to n+1th cells are V1 to V n+1 These voltage amplifiers G1 to G n+1 The nth voltage amplifier G in n One input end of the resistor R1 is connected to the first resistor R1 n-1 The other end of the first capacitor C1 n-1 One end of the nth voltage amplifier G n The other input terminal is connected to the first resistor R1 n The other end of the first capacitor C1 n One end of the n+1th voltage amplifier G n+1In addition, the nth voltage amplifier G n The output end of is connected to the nth input end of MPU 1.

[0066] The nth voltage amplifier G n The difference between the potential of the n-1th battery and the potential of the n-1th battery is amplified, wherein the potential of the n-1th battery is transmitted via the n-1th wiring VH n-1 and the n-1CR low-pass filter and the n-th battery cell B n The negative electrode of the nth battery is applied, and the nth battery potential is applied via the nth wiring VH n and the nth CR low pass filter and the nth battery cell B n The positive electrode is applied. That is, the nth voltage amplifier G n The nth battery cell B n The related inter-electrode voltage is taken as the nth cell voltage V n Output to the nth input terminal of MPU 1.

[0067] The n+1th voltage amplifier G n+1 One input end of the resistor R1 is connected to the first resistor R1 n The other end of the first capacitor C1 n One end of the nth voltage amplifier G n The other input terminal of the n+1th voltage amplifier G n+1 The other input terminal is connected to the first resistor R1 n+1 The other end of the first capacitor C1 n+1 In addition, the n+1th voltage amplifier G n+1 The output end of is connected to the n+1th input end in MPU 1.

[0068] The n+1th voltage amplifier G n+1 The difference between the potential of the nth battery and the potential of the n+1th battery is amplified, wherein the potential of the nth battery is transmitted via the nth wiring VH n and the nth CR low pass filter and the nth battery cell B n The positive electrode and the n+1th battery cell B n+1 The negative electrode of the n+1th battery is applied, and the potential of the n+1th battery is applied via the n+1th wiring VH n+1 and the n+1th CR low pass filter and from the n+1th battery cell B n+1 The positive electrode is applied. That is, the n+1th voltage amplifier G n+1 The n+1th battery cell B n+1 The related inter-electrode voltage is taken as the n+1th cell voltage V n+1 And output to the n+1th input terminal of MPU 1.

[0069] The MPU 1 has at least (n+1) input terminals and (n+1) output terminals. The nth input terminal among the (n+1) input terminals is connected to the nth voltage amplifier G n The n+1th input terminal is connected to the n+1th voltage amplifier G n+1 In addition, the nth output terminal is connected to the nth electronic switch D n The other input terminal of the n+1th output terminal is connected to the n+1th electronic switch D n+1 The other input terminal.

[0070] Such an MPU 1 includes at least a storage circuit for storing at least a predetermined monitoring program, a calculation circuit for executing the monitoring program, and (n+1) electronic switches D1 to D n+1 and (n+1) voltage amplifiers G1 to G n+1 The MPU 1 is an input / output circuit for inputting and outputting signals by executing a monitoring program of a storage circuit through an operation circuit, thereby controlling the first to n+1th electronic switches D1 to D n+1 The opening and closing of the discharge circuits, that is, the control unit for the operation of the first to n+1th discharge circuits.

[0071] That is, the MPU 1 generates the first to the n+1th voltage amplifiers G1 to G n+1 Input voltages of the first to n+1th cells V1 to V n+1 , generating the first to n+1th switching signals. The MPU 1 outputs the first to n+1th switching signals to the first to n+1th electronic switches D1 to D n+1 The other input terminal of the circuit controls the first to n+1 electronic switches D1 to D n+1 The opening and closing of the first to n+1th discharge circuits are operated.

[0072] Such a battery monitoring device A (disconnection detection device) is configured to detect the first to n+1th wiring lines VH1 to VH2. n+1 Each of the first to n+1 th CR low pass filters is provided, and the first to n+1 th electronic switches D1 to D n+1 The first to n+1th overcurrent protection functions are respectively provided.

[0073] Next, follow Figure 2 The flowchart shown explains the operation of the battery monitoring device A according to the present embodiment.

[0074] In addition, the following is for the adjacent battery cells B n , B n+1 In this operation description, the n+1th battery cell Bn+1 is called this cell, and the n+1th electronic switch D n+1 is called the switch. In addition, the nth battery cell B n The nth electronic switch D n It is called an adjacent switch.

[0075] First, the battery monitoring device A (disconnection detection device) according to the present embodiment is configured to monitor (n+1) battery cells B1, ..., B n , B n+1 The charging state is equalized and has the following circuit structure: if a wire break occurs in the wiring on the low potential side connected to a certain battery cell during the equalization discharge of the battery cell, the capacitor of the CR low-pass filter arranged in the wiring on the low potential side is charged with a voltage approximately twice the voltage normally applied.

[0076] For example Figure 3 As shown, when the n+1th electronic switch D n+1 The switch is set to the ON state to make the n+1th battery cell B n+1 (This cell) In the state of equalized discharge, if the nth wiring VH n If the wire is broken, the current I shown by the dotted line will flow, and the n+1th battery cell B n+1 The voltage of the positive terminal of (this cell) replaces the voltage of the nth cell B n The voltage of the positive terminal of the adjacent cell is applied to the first capacitor C1. n .

[0077] The nth battery cell B n (adjacent cell) and the n+1th battery cell B n+1 (this battery cell) is connected in series, and in addition, the nth battery cell B n (Adjacent cell) nth cell voltage V n With the n+1th battery cell B n+1 (This cell) The voltage of the n+1th cell V n+1 Roughly the same, so the n+1th battery cell B n+1 The voltage of the positive terminal of (this cell) is equivalent to that of the nth cell B n The voltage of the positive terminal of the adjacent cell is about twice that of the first capacitor C1. n The battery is charged by the approximately twice voltage, and the potential of one end is maintained at the approximately twice voltage.

[0078] Although the details will be described later, the MPU 1 of the battery monitoring device A is based on the first to n+1th voltage amplifiers G1 to G n+1 The first to n+1th differential voltages are input to detect the first to n+1th cell voltages V1 to Vn+1 , using the first to n+1th cell voltages V1 to V n+1 Detection of the first to n+1th wiring lines VH1 to VH n+1 The disconnection.

[0079] However, if the first capacitor C1 n The potential of one end of the nth wiring VH is maintained at a voltage approximately twice as high as the above voltage. n If the line is broken, the voltage of the nth and n+1th cells V n 、V n+1 becomes an abnormal voltage value. That is, the nth cell voltage V n The voltage value is about twice that of the normal cell voltage. n+1 The voltage value becomes substantially zero.

[0080] Thus, if the nth wiring VH n If the line is broken, the voltage of the nth and n+1th cells V n 、V n+1 Although it is an abnormal voltage value, the voltage V n 、V n+1 The abnormal voltage value is not only on the nth wiring VH n When the line is broken, the nth battery cell B n (adjacent cell) or n+1th battery cell B n+1 (This battery cell) will also be generated when an abnormality occurs. In order to distinguish the nth battery cell B n (adjacent cell) or n+1th battery cell B n+1 (the cell) detects an abnormality in the nth wiring VH n The disconnection of the nth battery cell B adjacent to each other needs to be evaluated. n (adjacent battery cell) and the n+1th battery cell B n+1 (This cell) The voltage V of the nth and n+1th cells n 、V n+1 The changing trend of the difference voltage Vdiff and the sum voltage Vsum.

[0081] If MPU 1 detects the voltage V of the nth and n+1th cells n 、V n+1 If there is an abnormality, the nth electronic switch D n The switch is set to the ON state to make the first capacitor C1 n That is, since the n+1th battery cell B n+1 During the equalization discharge of (this battery cell), the voltage V n 、V n+1becomes abnormal, so the first capacitor C1 is temporarily n Discharge (eliminate electricity), and on this basis re-detect the voltage V of the nth and n+1th cells n 、V n+1 .

[0082] The MPU 1 performs such a first capacitor C1 n When the voltage of the nth cell V is removed, it is determined whether the switch of the neutralization switch is switched (step S1). n If the voltage V n If it is less than or equal to a predetermined threshold value, it is determined as “no neutralization switch switching determination”.

[0083] That is, at the nth cell voltage V n If the threshold value is exceeded, the MPU 1 determines that the nth electronic switch D n The nth overcurrent protection function of the adjacent switch works, and the nth cell voltage V n If the value is below a predetermined threshold, the MPU 1 determines that the nth electronic switch D n The nth overcurrent protection function of the adjacent switch does not operate. If the determination in step S1 is “No”, that is, if the nth electronic switch D n When the nth overcurrent protection function of the adjacent switch does not work, the MPU 1 switches the nth electronic switch D n (Adjacent switch) is set as the static eliminating switch (step S2).

[0084] On the other hand, if the determination in step S1 is "Yes", that is, if it is determined that the nth electronic switch D n When the nth overcurrent protection function is activated, MPU 1 switches the n+1th electronic switch D n+1 The switch is set as a neutralization switch (step S3). Then, the MPU 1 activates the neutralization switch (sets it to an on state) to activate the first capacitor C1. n De-staticization (step S4).

[0085] At the nth electronic switch D n When the (adjacent switch) is set as the static eliminating switch, the first capacitor C1 n The charge accumulated in the n → Second resistor R1 n →nth electronic switch D n (Adjacent switch) → third resistor R3 n →First resistor R1 n-1 →First capacitor C1n-1 And the electricity is removed.

[0086] At the n+1th electronic switch D n+1 When (this switch) is set as a static elimination switch, the first capacitor C1 n The charge accumulated in the n →The third resistor R3 n+1 →The n+1th electronic switch D n+1 (this switch) → first resistor R3 n+1 →First resistor R1 n+1 →First capacitor C1 n+1 And the electricity is removed.

[0087] That is, Figure 4 As shown, the neutralization switch is switched in a time-series manner according to the operating state of the n-th overcurrent protection function. Therefore, the neutralization switch is fixed and the charge accumulated in the first capacitor C1n cannot be neutralized.

[0088] Thus, if the first capacitor C1 n When the charge removal is completed, MPU 1 obtains the nth battery cell B n (adjacent battery cell) and the n+1th battery cell B n+1 (This cell) The voltage V of the nth and n+1th cells n 、V n+1 (Switch S5). Then, the MPU 1 determines whether the (n+1)th battery cell B n+1 (This cell) The voltage of the n+1th cell V n+1 Whether it exceeds the voltage threshold Vth (step S6).

[0089] If the determination in step S6 is "yes", the MPU 1 switches the neutralization switch (step S7). That is, if the nth electronic switch Dn (adjacent switch) is set as the neutralization switch in step S2, the MPU 1 changes the neutralization switch to the n+1th electronic switch Dn+1 (this switch).

[0090] On the other hand, when the n+1th electronic switch Dn+1 (this switch) is set as the neutralization switch in step S3, the MPU 1 changes the neutralization switch to the nth electronic switch Dn (adjacent switch). After switching the neutralization switch, the MPU 1 performs a disconnection determination (step S8) and ends the disconnection evaluation process.

[0091] The above-mentioned disconnection determination utilizes the n-th battery cells B adjacent to each other as described above. n (adjacent battery cell) and the n+1th battery cell B n+1 (This cell) The voltage V of the nth and n+1th cells n、V n+1 、nth cell voltage V n and the voltage of the n+1th cell V n+1 The difference voltage Vdiff and the nth cell voltage V n and the voltage of the n+1th cell V n+1 Determination of the changing trend of the added voltage Vsum.

[0092] By turning on / off the nth discharge circuit and the n+1th discharge circuit, for example, the nth discharge circuit, at a predetermined duty ratio, the nth battery cell B n In the case of slow discharge, Figure 5A As shown, even if the nth wiring VH n The disconnection of the n+1th cell voltage V n+1 The voltage V of the nth cell does not change either. n Since the nth wiring VH n The line was broken and it slowly descended.

[0093] In this case, the difference voltage Vdiff gradually increases due to the disconnection of the n-th wiring VHn. n If the nth wiring line VH is disconnected, the added voltage Vsum will not change. n If the line is broken, the change trends (slopes) of the difference voltage Vdiff and the sum voltage Vsum are completely different.

[0094] On the other hand, the nth battery cell B is discharged by turning on / off the nth discharge circuit at a predetermined duty ratio. n In the case of slow discharge, when the nth battery cell B n If a voltage abnormality (battery abnormality) occurs in (adjacent cells), Figure 5B As shown, the voltage of the nth cell V n and the voltage of the n+1th cell V n+1 All slowly decreased.

[0095] In addition, if the nth battery cell B n If the voltage of the adjacent cell (battery abnormality) is abnormal, the difference voltage Vdiff gradually increases. n If the voltage of the adjacent cell (battery abnormality) is abnormal, the added voltage Vsum gradually decreases. n If the voltage of the (adjacent cell) is abnormal (battery abnormality), the difference voltage Vdiff and the added voltage Vsum have the same absolute value although the directions of the changing trends (slopes) are different.

[0096] The MPU 1 uses the voltages V n 、V n+1 , the difference voltage Vdiff between the nth cell voltage Vn and the n+1th cell voltage Vn+1, and the added voltage Vsum between the nth cell voltage Vn and the n+1th cell voltage Vn+1, which is different from the nth battery cell B n The nth wiring VH is detected when the voltage of the adjacent cell is abnormal (battery abnormality). n The disconnection.

[0097] If the determination result in step S6 is “No”, the MPU 1 determines whether the n-th battery cell B n (Adjacent cell) nth cell voltage V n If the determination result of step S9 is “Yes”, the MPU 1 performs a disconnection determination (step S10), and if the determination result of step S9 is “No”, the MPU 1 performs a no disconnection determination (step S11) and ends the disconnection evaluation process.

[0098] According to this embodiment, since the discharge switch (electronic switch) for discharging the capacitor of the CR low-pass filter charged by twice the voltage can be changed rather than fixed, even if each wiring has a CR low-pass filter and the electronic switch of the discharge circuit has an overcurrent protection function, the wiring break can be normally detected based on the battery cell voltage.

[0099] That is, according to the present embodiment, the overcurrent protection function is activated by applying a voltage twice that of the capacitor of the CR low-pass filter, and the discharge switch (electronic switch) of the discharge circuit connected to the capacitor cannot be switched to the ON state, and the charge of the capacitor cannot be discharged. As a result, according to the present embodiment, it is possible to provide a battery monitoring device A (disconnection detection device) that can avoid the situation where disconnection detection cannot be performed due to the capacitor being kept in a charged state.

[0100] In addition, the present invention is not limited to the above-mentioned embodiment, and for example, the following modified examples are conceivable.

[0101] (1) In the above embodiment, by using the voltages V of the adjacent nth and n+1th cells n 、V n+1 , the difference voltage Vdiff between the nth cell voltage Vn and the n+1th cell voltage Vn+1, and the added voltage Vsum between the nth cell voltage Vn and the n+1th cell voltage Vn+1, and the nth wiring VH is detected. n However, the present invention is not limited to this.

[0102] For example, as described in Japanese Patent Application Publication No. 2017-158269, a difference voltage Vdiff and a summed voltage Vsum when a pair of adjacent battery cells are discharged at different duty ratios may be used to identify a disconnection in a transmission line and a voltage abnormality in a battery cell (battery abnormality).

[0103] (2) In the above embodiment, the disconnection detection in the battery B (battery pack) mounted on the electric vehicle is described, but the present invention is not limited thereto and can also be applied to batteries other than the battery B (battery pack) mounted on the vehicle.

[0104] Industrial Applicability

[0105] The present disclosure can be utilized in a disconnection detection device and a battery monitoring device.

[0106] Description of Reference Numerals

[0107] A battery monitoring device, B battery, B n , B n+1 Battery cell, C1 n-1 、C1 n 、C1 n+1 First capacitor, C2 n 、C2 n+1 The second capacitor, D n , D n+1 Electronic switch, E n 、E n+1 Differential amplifier, F n 、F n+1 Control circuit, G n , G n+1 Voltage amplifier, R1 n-1 、R1 n 、R1 n+1 The first resistor, R2 n , R2 n+1 First resistor, R3 n 、R3 n+1 The first resistor, T n-1 , T n , T n+1 Input end, 1MPU.

Claims

1. A disconnection detection device, comprising: a voltage detection circuit, for a battery having a plurality of battery cells, detecting the cell voltage of the battery cell, wherein: The plurality of battery cells are connected in series with each other and are respectively connected in parallel to a discharge circuit having an electronic switch; a capacitor-resistance low-pass filter, i.e., a CR low-pass filter, is provided on each of a plurality of wirings connecting the battery cells and the voltage detection circuit; and a control unit is configured to make the discharge circuit discharge uniformly and detect disconnection of the wiring based on the cell voltage. In the wire breakage detection device, The electronic switch has a protection function of prohibiting migration to an on state, The control unit operates one of the pair of electronic switches associated with a pair of adjacent battery cells to remove charges accumulated in the CR low-pass filter, and detects disconnection of the wiring based on the cell voltage after the removal of charges.

2. The wire breakage detection device according to claim 1, wherein: When the control unit determines that the protection function of the electronic switch preset as the static elimination switch of the CR low-pass filter is activated, the control unit sets the electronic switch paired with the electronic switch that has activated the protection function to an on state, thereby eliminating static electricity from the CR low-pass filter.

3. The wire breakage detection device according to claim 1 or 2, wherein: The control unit recognizes disconnection of the wiring and abnormality of the battery cell based on a difference voltage and a sum voltage between cell voltages of a pair of the battery cells when at least one of the discharge circuits is discharged.

4. The wire breakage detection device according to any one of claims 1 to 3, wherein: The discharge circuit is a series circuit of the electronic switch and a resistor.

5. A battery monitoring device comprising the disconnection detection device according to any one of claims 1 to 4, The battery monitoring device controls the connection between the battery and the load based on the disconnection detection result of the disconnection detection device.

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