Battery pack sampling line disconnection detection device and method

Abstract

The present invention provides a device and method for detecting the disconnection of a sampling line of a storage battery pack. The disconnection detection device comprises: a current limiting resistor module, comprising n current limiting resistors and a reference current limiting resistor; a voltage dividing resistor module, comprising n voltage dividing resistors; a detection switch module, wherein one end of each detection switch is connected to the corresponding voltage dividing resistor, and the other end is connected to the corresponding current limiting resistor and the voltage dividing resistor corresponding to the adjacent high-section single battery; a switching resistor module, comprising n switching resistor units; a voltage acquisition module, wherein each voltage acquisition unit is used for the single battery voltage and the real-time diagnosis voltage; a comparison and judgment module, which turns off the corresponding switch tube when judging that the single battery voltage is greater than a preset reference voltage; and a microprocessor, which controls the switch of the detection switch, calculates the theoretical diagnosis voltage, and determines that the corresponding acquisition line is in a disconnected state when judging that the real-time diagnosis voltage is not within the error range of the corresponding theoretical diagnosis voltage.

Description

Technical Field

[0001] The invention belongs to the technical field of battery pack sampling line break detection, and in particular relates to a battery pack sampling line break detection device and method. Background Art

[0002] As a storage energy and driving energy source, battery packs are widely used in aerospace, automobile, electricity and other related fields, especially in recent years, they have been widely used and vigorously developed. In the process of using batteries, it is indispensable to use a battery management system (BMS). The widespread use of BMS has exposed many problems that will affect the normal operation of the battery system, among which the problem of battery disconnection detection is particularly prominent.

[0003] In the current BMS system, the line break detection is usually carried out as follows Figure 5 The series resistor sampling line disconnection detection device 300 shown includes a current limiting resistor module 310, a clamping management module 320, a voltage dividing resistor module 330 and a detection switch module 340. The detection steps are as follows:

[0004] Step 1: The detection starts, and the system detects the voltages V1 to Vn of the single cells B1 to Bn and records them;

[0005] Step 2: Start the disconnection detection odd switches K1 to Kn-1, and record the voltages U1 to Un-1 of the odd-numbered cells. According to the resistor voltage division principle, the theoretical voltages corresponding to the odd-numbered cells are Ut1=V1*Rf1 / (Rf1+Rx0+Rx1), ..., Utn-1=Vn-1*Rfy-1 / (Rfy-1+Rxn-2+Rxn-1);

[0006] Step 3: Start the disconnection detection even-numbered switches K2 to Kn, and record the voltages U2 to Un of the even-numbered cells. According to the principle of resistor voltage division, the theoretical voltages corresponding to the even-numbered cells are Ut2 = V2*Rf2 / (Rf2+Rx1+Rx2), ..., Utn = Vn*Rfn / (Rfn+Rxn-1+Rxn);

[0007] Step 4: Perform disconnection judgment and set the system sampling error to 5%. When U1 / Ut1=0.95-1.05, ..., Un-1 / Utn-1=0.9-1.05, U2 / Ut2=0.95-1.05, ..., Un / Utn=0.95-1.05, the corresponding sampling line has no disconnection. Otherwise, it is determined that the corresponding sampling line is disconnected.

[0008] When the above detection device is used for disconnection detection, the voltage-dividing resistors Rf1, Rf2, Rfn-1, and Rfn are connected to the system, so that the impedance of the corresponding single battery is reduced after the resistor is connected, so the divided voltage changes. However, since all the voltage-dividing resistors are connected in series, the reduced voltage will be accumulated on the adjacent batteries. At the same time, each voltage-dividing resistor has a fixed resistance value and cannot be switched according to the voltage. Therefore, when detecting, it is easy to cause the adjacent battery to trigger overvoltage when the high voltage is high, and to trigger overvoltage and undervoltage when the low voltage is low. Overvoltage and undervoltage of a single battery is a serious fault and will cause the system to stop working. Summary of the invention

[0009] The present invention is made to solve the above-mentioned problem, and aims to provide a battery pack sampling line break detection device and method, which can accurately detect the battery pack sampling line break while effectively avoiding the single cell over-voltage and under-voltage problems during the break detection.

[0010] In order to achieve the above object, the present invention adopts the following technical solutions:

[0011] <Option 1>

[0012] The present invention provides a sampling line disconnection detection device for a battery pack, which is used for detecting disconnection of n sampling lines respectively connected to the positive electrodes of n single cells in the battery pack, wherein the sampling lines of the low-cell single cells are simultaneously connected to the negative electrodes of the adjacent high-cell single cells, and the negative electrodes of the lowest-cell single cells are connected to the reference sampling line. The device has the following characteristics, including: a current limiting resistor module, comprising n current limiting resistors respectively connected to the n sampling lines, and a reference current limiting resistor connected to the reference sampling line; a voltage dividing resistor module, comprising n voltage dividing resistors respectively corresponding to the n single cells, each voltage dividing resistor being connected in series between two corresponding current limiting currents or between a corresponding current limiting resistor and a reference current limiting resistor; a detection switch module, comprising n detection switches respectively corresponding to the n voltage dividing resistors, one end of each detection switch being connected to the corresponding voltage dividing resistor, and the other end being connected to the corresponding current limiting resistor and the voltage dividing resistor corresponding to the adjacent high-cell single cell; a switching resistor module, comprising n switching resistor units respectively connected in parallel to the n voltage dividing resistors, each switching resistor unit comprising a switching resistor and a switch tube connected in series; a voltage acquisition module A block, comprising n voltage acquisition units corresponding to n single cells respectively, each voltage acquisition unit is used to acquire the voltage across the corresponding single cell as the single cell voltage when all detection switches are in a closed state, and to acquire the voltage across the corresponding voltage-dividing resistor as the real-time diagnosis voltage when the corresponding detection switch is in an open state and the remaining detection switches are in a closed state; a comparison and judgment module, comprising n comparison and judgment units corresponding to n single cells respectively, each comparison and judgment module is used to compare and judge the single cell voltage acquired by the corresponding voltage acquisition unit with a preset reference voltage, and to turn off the corresponding switch tube when it is judged that the single cell voltage is greater than the preset reference voltage, so that the corresponding switching resistor and the voltage-dividing resistor are in a disconnected state; and a microprocessor, controlling the switching of the detection switch, calculating the voltage across the corresponding voltage-dividing resistor as the theoretical diagnosis voltage based on the single cell voltage and the switching state of the corresponding switch tube, and judging whether the real-time diagnosis voltage is within the error range of the corresponding theoretical diagnosis voltage, and when the judgment result is no, judging that the corresponding acquisition line is in a disconnected state, and n is a positive integer greater than or equal to 2.

[0013] In the battery pack sampling line break detection device provided by the present invention, it can also have the following characteristics: it also includes: a clamping management module, wherein the clamping management module includes n voltage-stabilizing diodes corresponding to n single cells respectively, and each voltage-stabilizing diode is connected in series between two corresponding current-limiting resistors or between a corresponding current-limiting resistor and a reference current-limiting resistor.

[0014] The battery pack sampling line break detection device provided by the present invention may also have the following features: wherein the voltage acquisition unit contains an operational amplifier, the two input ends of the operational amplifier are respectively connected to the corresponding two current limiting resistors or the corresponding current limiting resistor and the reference current limiting resistor, and the output end is used to transmit the single cell voltage to the microprocessor and the corresponding comparison and judgment unit and to transmit the real-time diagnostic voltage to the microprocessor.

[0015] In the battery pack sampling line break detection device provided by the present invention, it can also have the following characteristics: wherein, the voltage acquisition unit also contains two resistors corresponding to the two input terminals as differential sampling resistors, and a resistor as an operational amplifier current limiting resistor, the differential sampling resistor is connected in series between the corresponding input terminal and the current limiting resistor or between the corresponding input terminal and the reference current limiting resistor, and the operational amplifier current limiting resistor is connected in series between the output terminal and the corresponding comparison and judgment unit.

[0016] The battery pack sampling line break detection device provided by the present invention may also have the following features: wherein the comparison and judgment unit includes a comparator, the negative phase input terminal of the comparator is connected to the output terminal of the corresponding operational amplifier, the positive phase input terminal is used to receive a preset reference voltage, and the output terminal of the comparator is connected to the control terminal of the corresponding switch tube.

[0017] The battery pack sampling line break detection device provided by the present invention may also have the following features: wherein the comparison and judgment unit further includes a pull-up resistor, one end of the pull-up resistor is connected to the output end of the corresponding comparator, and the other end is used to receive the pull-up voltage.

[0018] The battery pack sampling line disconnection detection device provided by the present invention may also have the following feature: wherein the switch tube is a MOSFET tube.

[0019] <Option 2>

[0020] The present invention also provides a method for detecting a disconnection of a sampling line of a battery pack, which has the following characteristics and comprises the following steps:

[0021] Control all detection switches to be in a closed state, and collect the voltage across each single battery as the single battery voltage;

[0022] Determine in turn whether the voltage of each single cell is greater than a preset reference voltage, if so, turn off the corresponding switch tube, if not, turn on the corresponding switch tube;

[0023] Turn on each detection switch in turn and keep the other detection switches in a closed state, and collect the voltage across the corresponding voltage-dividing resistor as a real-time diagnostic voltage;

[0024] The voltage across the corresponding voltage-dividing resistor is calculated based on the single cell voltage and the switch state of the corresponding switch tube as a theoretical diagnosis voltage;

[0025] It is determined whether the real-time diagnosis voltage is within the error range of the corresponding theoretical diagnosis voltage. When the determination result is no, it is determined that the corresponding sampling line is in a disconnected state.

[0026] Functions and Effects of the Invention

[0027] According to the battery pack sampling line disconnection detection device and method involved in the present invention, because one end of each detection switch is connected to the corresponding voltage-dividing resistor, and the other end is connected to the corresponding current-limiting resistor and the voltage-dividing resistor corresponding to the adjacent high-cell single battery, the switching resistor module includes n switching resistor units respectively connected in parallel with the n voltage-dividing resistors, each switching resistor unit contains a switching resistor and a switch tube connected in series, each voltage acquisition unit can collect the voltage across the corresponding single battery as the single battery voltage when all detection switches are in the closed state, and collect the voltage across the corresponding voltage-dividing resistor as the real-time diagnostic voltage when the corresponding detection switch is in the open state and the remaining detection switches are in the closed state. A comparison and judgment module can compare and judge the single cell voltage collected by the corresponding voltage collection unit with the preset reference voltage. When it is judged that the single cell voltage is greater than the preset reference voltage, the corresponding switch tube is turned off, so that the corresponding switching resistor and the voltage-dividing resistor are in a disconnected state. The microprocessor can calculate the voltage across the corresponding voltage-dividing resistor as the theoretical diagnostic voltage based on the single cell voltage and the switching state of the corresponding switch tube, and judge whether the real-time diagnostic voltage is within the error range of the corresponding theoretical diagnostic voltage. When the judgment result is no, it is determined that the corresponding collection line is in a disconnected state. Therefore, the present invention can accurately detect the disconnection of the battery pack sampling line while effectively avoiding the problem of single cell over-voltage and under-voltage during disconnection detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a structural block diagram of a battery pack sampling line disconnection detection device in an embodiment of the present invention;

[0029] Figure 2 is a circuit diagram of a battery pack sampling line disconnection detection device in an embodiment of the present invention;

[0030] Figure 3 is a simplified detection circuit diagram of a single cell B1 in an embodiment of the present invention when the switch tube Q1 is in the off state;

[0031] Figure 4 is a simplified detection circuit diagram of a single cell B1 in an embodiment of the present invention when the switch tube Q1 is in an on state; and

[0032] Figure 5 The invention relates to a battery pack sampling line disconnection detection device which adopts a series voltage-dividing resistor in the prior art. DETAILED DESCRIPTION

[0033] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the following embodiments and the accompanying drawings specifically illustrate the battery pack sampling line break detection device and method provided by the present invention.

[0034] <Example>

[0035] Figure 1 is a structural block diagram of a battery pack sampling line disconnection detection device in an embodiment of the present invention; Figure 2 1 is a circuit diagram of a battery pack sampling line disconnection detection device in an embodiment of the present invention.

[0036] like Figure 1 and Figure 2 As shown, in this embodiment, the battery pack sampling line disconnection detection device 100 is used to detect disconnection of n sampling lines L1, L2, ..., Ln respectively connected to the positive electrodes of n single cells B1, B2, ..., Bn in the battery pack 200, where n is a positive integer not less than 2; the sampling line of the low-cell single cell is simultaneously connected to the negative electrode of the adjacent high-cell single cell, that is, the sampling line L1 is simultaneously connected to the negative electrode of the single cell B2, the sampling line L2 is simultaneously connected to the negative electrode of the single cell B3, and so on; the negative electrode of the lowest single cell B1 is connected to the reference sampling line L0. The battery pack sampling line disconnection detection device 100 includes a current limiting resistor module 10, a clamping management module 20, a voltage dividing resistor module 30, a detection switch module 40, a switching resistor module 50, a voltage acquisition module 60, a comparison and judgment module 70, and a microprocessor 80.

[0037] like Figure 1 and Figure 2 As shown, the current limiting resistor module 10 is used to limit and isolate the current of the battery to prevent overcurrent from damaging other components. The current limiting resistor module 10 includes n current limiting resistors Rx1, Rx2, ..., Rxn and a reference current limiting resistor Rx0.

[0038] The current limiting resistors Rx1, Rx2, ..., Rxn are connected to the sampling lines L1, L2, ..., Ln in a one-to-one correspondence.

[0039] The reference current limiting resistor Rx0 is connected to the reference sampling line L0.

[0040] like Figure 1 and Figure 2As shown, the clamp management module 20 is used for clamp management of both ends of each single battery, and includes n voltage stabilizing diodes D1, D2, ..., Dn corresponding to n single batteries respectively.

[0041] Each voltage-stabilizing diode is connected in series between two current-limiting resistors corresponding to the corresponding single battery or between the corresponding current-limiting resistor and the reference current-limiting resistor. That is, the voltage-stabilizing diode D1 is connected in series between the current-limiting resistor Rx1 and the reference current-limiting resistor Rx0, the voltage-stabilizing diode D2 is connected in series between the current-limiting resistor Rx2 and the current-limiting resistor Rx1, and so on.

[0042] The working principle of the voltage zener diode is that when the voltage across it is greater than the preset clamping voltage, the voltage is stabilized to the reference voltage Vz of the diode. The reference voltage Vz is 1.5-1.8 times the maximum voltage of the corresponding single cell. In this embodiment, the reference voltage Vz is 1.5 times the maximum voltage of the corresponding single cell.

[0043] like Figure 1 and Figure 2 As shown, the voltage-dividing resistor module 30 is used to divide and sample the voltage across each single battery, and includes n voltage-dividing resistors Rf1, Rf2, ..., Rfn corresponding to the n single batteries respectively.

[0044] Each voltage-dividing resistor is connected in series between two current-limiting resistors corresponding to the corresponding single cell or between the corresponding current-limiting resistor and the reference current-limiting resistor. That is, the voltage-dividing resistor Rf1 is connected in series between the current-limiting resistor Rx1 and the reference current-limiting resistor Rx0, the voltage-dividing resistor Rf2 is connected in series between the current-limiting resistor Rx2 and the current-limiting resistor Rx1, and so on.

[0045] like Figure 1 and Figure 2 As shown, the detection switch module 40 includes n detection switches K1, K2, ..., Kn corresponding to n voltage-dividing resistors. Each detection switch is used to connect the voltage-dividing resistor and the corresponding current-limiting resistor in the disconnection detection state or disconnect the voltage-dividing resistor and the corresponding current-limiting resistor in the non-disconnection detection state.

[0046] One end of the detection switch is connected to the corresponding voltage-dividing resistor, and the other end is connected to the corresponding current-limiting resistor and the voltage-dividing resistor corresponding to the adjacent high-cell battery. That is, one end of the detection switch K1 is connected to the voltage-dividing resistor Rf1, and the other end is connected to the current-limiting resistor Rx1 and the voltage-dividing resistor Rf2; one end of the detection switch K2 is connected to the voltage-dividing resistor Rf2, and the other end is connected to the current-limiting resistor Rx2 and the voltage-dividing resistor Rf3; and so on.

[0047] like Figure 1 and Figure 2As shown, the switch resistor module 50 includes n switch resistor units 51 respectively connected in parallel with n voltage dividing resistors.

[0048] Each switching resistor unit 51 includes a switching resistor and a switch tube connected in series. For example, the switching resistor Rq1 and the switch tube Q1 are connected in series and then connected in parallel with the voltage-dividing resistor Rf1, the switching resistor Rq2 and the switch tube Q2 are connected in series and then connected in parallel with the voltage-dividing resistor Rf2, and so on. In this embodiment, the switch tube adopts a MOSFET tube.

[0049] like Figure 1 and Figure 2 As shown, the voltage acquisition module 60 includes n voltage acquisition units 61 corresponding to n single cells respectively. Each voltage acquisition unit 61 is used to acquire the voltage across the corresponding single cell as the single cell voltage when all detection switches are in the closed state, and to acquire the voltage across the corresponding voltage divider resistor as the real-time diagnosis voltage when the corresponding detection switch is in the open state and the remaining detection switches are in the closed state.

[0050] Each voltage acquisition unit 61 contains an operational amplifier, two resistors corresponding to the two input terminals of the operational amplifier as differential sampling resistors, and a resistor as an operational amplifier current limiting resistor. One end of each of the two differential sampling resistors is connected to the two input terminals of the corresponding operational amplifier, and the other end is connected to the corresponding two current limiting resistors or the corresponding current limiting resistor and the reference current limiting resistor; one end of the operational amplifier current limiting resistor is connected to the output terminal of the corresponding operational amplifier. That is, one end of the differential sampling resistors Rc1 and Rc2 is connected to the two input terminals of the operational amplifier A1, and the other end is connected to the reference current limiting resistor Rx0 and the current limiting resistor Rx1, and one end of the operational amplifier current limiting resistor Ra1 is connected to the output terminal of the operational amplifier A1; one end of the differential sampling resistors Rc3 and Rc4 is connected to the two input terminals of the operational amplifier A2, and the other end is connected to the current limiting resistors Rx1 and Rx2, and one end of the operational amplifier current limiting resistor Ra2 is connected to the output terminal of the operational amplifier A2; and so on.

[0051] like Figure 1 and Figure 2 As shown, the comparison and judgment module 70 includes n comparison and judgment units 71 corresponding to n single cells respectively. Each comparison and judgment module 71 is used to compare and judge the single cell voltage collected by the corresponding voltage collection unit 61 with the preset reference voltage. When it is judged that the single cell voltage is greater than the preset reference voltage, the corresponding switch tube is turned off so that the corresponding switching resistor and the voltage-dividing resistor are in a disconnected state; when it is judged that the single cell voltage is not greater than the preset reference voltage, the corresponding switch tube is turned on so that the corresponding switching resistor and the voltage-dividing resistor are in a connected state.

[0052] Each comparison judgment unit 71 includes a comparator and a resistor serving as a pull-up resistor.

[0053] The negative phase input terminal of the comparator is connected to the other end of the corresponding operational current limiting resistor, the positive phase input terminal is used to receive the preset reference voltage Vref, and the output terminal of the comparator is connected to the control terminal of the corresponding switch tube. That is, the negative phase input terminal of the comparator P1 is connected to the other end of the operational amplifier current limiting resistor Ra1, and the output terminal is connected to the control terminal of the switch tube Q1; the negative phase input terminal of the comparator P2 is connected to the other end of the operational amplifier current limiting resistor Ra2, and the output terminal is connected to the control terminal of the switch tube Q2; and so on.

[0054] One end of the pull-up resistor is connected to the output end of the corresponding comparator, and the other end is used to connect the pull-up voltage VCC. That is, the pull-up resistor Rs1 is connected to the output end of the comparator P1, the pull-up resistor Rs2 is connected to the output end of the comparator P2, and so on.

[0055] like Figure 1 As shown, the microprocessor 80 is used to control the switching of the detection switch; it is also used to calculate the voltage across the corresponding voltage-dividing resistor as a theoretical diagnostic voltage based on the single cell voltage and the switching state of the corresponding switch tube; it is also used to determine whether the real-time diagnostic voltage is within the error range of the corresponding theoretical diagnostic voltage. When the judgment result is no, it is determined that the corresponding acquisition line is in a disconnected state.

[0056] In this embodiment, a detection method of a battery pack sampling line disconnection device 100 is used, comprising the following steps:

[0057] In step S1 , the microcontroller 80 controls all detection switches to be in a closed state, and the voltage acquisition module 60 acquires the voltage across each single cell as the single cell voltage.

[0058] In step S2, the microcontroller 80 determines in turn whether the voltage of each single battery is greater than a preset reference voltage. If so, the corresponding switch tube is turned off; if not, the corresponding switch tube is turned on.

[0059] Step S3, turn on each detection switch in turn and keep the other detection switches in an off state, and the voltage acquisition module 60 acquires the voltage across the corresponding voltage-dividing resistor as a real-time diagnosis voltage.

[0060] Step S4, the microcontroller 80 calculates the voltage across the corresponding voltage-dividing resistor as a theoretical diagnosis voltage based on the single cell voltage and the switch state of the corresponding switch tube;

[0061] In step S5, the microcontroller 80 determines whether the real-time diagnostic voltage is within the error range of the corresponding theoretical diagnostic voltage. When the determination result is no, it is determined that the corresponding sampling line is in a disconnected state.

[0062] The following takes the acquisition line L1 of the single battery B1 as an example to illustrate the calculation of the theoretical diagnosis voltage and the disconnection detection.

[0063] Figure 3 is a simplified detection circuit diagram of a single cell B1 in an embodiment of the present invention when the switch tube Q1 is in the off state; Figure 4 1 is a simplified detection circuit diagram of a single battery B1 when the switch tube Q1 is in the on state in an embodiment of the present invention.

[0064] The single cell voltage and the real-time diagnosis voltage corresponding to the single cell B1 are set to Uz1 and Us1 respectively, and the preset reference voltage is Vref.

[0065] (1) If Uz1>Vref, the corresponding comparator P1 outputs a low level, so that the switch tube Q1 is in the off state, thereby disconnecting the switching resistor Rq1 and the voltage divider resistor Rf1. At this time, the simplified detection circuit is as follows: Figure 3 shown.

[0066] The theoretical diagnostic voltage Ut1-1 corresponding to the single battery B1 is:

[0067] Ut1-1=Uz1×Rf1 / (Rf1+Rx0+Rx1)

[0068] The system sampling is set to 5%. If Us1 / Ut1-1=0.95…1.05, it is determined that the sampling line L1 is not broken, otherwise it is determined that the sampling line L1 is broken.

[0069] (2) If Uz1≤Vref, the corresponding comparator P1 outputs a high level, so that the switch tube Q1 is in the on state, thereby connecting the switching resistor Rq1 and the voltage divider resistor Rf1. At this time, the simplified detection circuit is as follows: Figure 4 shown.

[0070] The theoretical diagnostic voltage Ut1-2 corresponding to the single battery B1 is:

[0071] Ut1-2=Uz1×(Rf1 / / Rq1) / (Rf1 / / Rq1+Rx0+Rx1)

[0072] The system sampling is set to 5%. If Us1 / Ut1-2=0.95…1.05, it is determined that the sampling line L1 is not broken, otherwise it is determined that the sampling line L1 is broken.

[0073] Functions and Effects of the Embodiments

[0074] According to the battery pack sampling line disconnection detection device and method involved in this embodiment, because one end of each detection switch is connected to the corresponding voltage-dividing resistor, and the other end is connected to the corresponding current-limiting resistor and the voltage-dividing resistor corresponding to the adjacent high-cell single battery, the switching resistor module includes n switching resistor units respectively connected in parallel with the n voltage-dividing resistors, and each switching resistor unit contains a switching resistor and a switch tube connected in series. Each voltage acquisition unit can collect the voltage across the corresponding single battery as the single battery voltage when all detection switches are in the closed state, and collect the voltage across the corresponding voltage-dividing resistor as the real-time diagnostic voltage when the corresponding detection switch is in the open state and the remaining detection switches are in the closed state. A comparison and judgment module can compare and judge the single cell voltage collected by the corresponding voltage collection unit with the preset reference voltage. When it is judged that the single cell voltage is greater than the preset reference voltage, the corresponding switch tube is turned off, so that the corresponding switching resistor and the voltage-dividing resistor are in a disconnected state. The microprocessor can calculate the voltage across the corresponding voltage-dividing resistor as the theoretical diagnostic voltage based on the single cell voltage and the switching state of the corresponding switch tube, and judge whether the real-time diagnostic voltage is within the error range of the corresponding theoretical diagnostic voltage. When the judgment result is no, it is determined that the corresponding collection line is in a disconnected state. Therefore, this embodiment can accurately detect the disconnection of the battery pack sampling line while effectively avoiding the problem of single cell over-voltage and under-voltage during disconnection detection.

[0075] The above-mentioned embodiments are preferred examples of the present invention and are not intended to limit the protection scope of the present invention.

Claims

1. A battery pack sampling line disconnection detection device, used for detecting disconnection of n sampling lines respectively connected to the positive electrodes of n single cells in a battery pack, wherein the sampling line of a low-cell single cell is simultaneously connected to the negative electrode of an adjacent high-cell single cell, and the negative electrode of the lowest-cell single cell is connected to a reference sampling line, characterized in that: include: a current limiting resistor module, comprising n current limiting resistors respectively connected to the n sampling lines, and a reference current limiting resistor connected to the reference sampling line; A voltage-dividing resistor module, comprising n voltage-dividing resistors corresponding to the n single cells respectively, each of the voltage-dividing resistors being connected in series between two corresponding current-limiting resistors or between a corresponding current-limiting resistor and a reference current-limiting resistor; A detection switch module, comprising n detection switches corresponding to the n voltage-dividing resistors respectively, one end of each detection switch being connected to the corresponding voltage-dividing resistor, and the other end being connected to the corresponding current-limiting resistor and the voltage-dividing resistor corresponding to the adjacent high-cell single battery; A switching resistor module, comprising n switching resistor units respectively connected in parallel with the n voltage-dividing resistors, each switching resistor unit comprising a switching resistor and a switch tube connected in series, wherein the switch tube is a MOSFET tube; A voltage acquisition module, comprising n voltage acquisition units corresponding to the n single cells respectively, each voltage acquisition unit being used to acquire the voltage across the corresponding single cell as the single cell voltage when all the detection switches are in a closed state, and to acquire the voltage across the corresponding voltage-dividing resistor as the real-time diagnostic voltage when the corresponding detection switch is in an open state and the remaining detection switches are in a closed state; A comparison and judgment module, comprising n comparison and judgment units corresponding to the n single cells respectively, each comparison and judgment module is used to compare and judge the single cell voltage collected by the corresponding voltage collection unit with a preset reference voltage, and when it is judged that the single cell voltage is greater than the preset reference voltage, the corresponding switch tube is turned off, so that the corresponding switching resistor and the voltage dividing resistor are in a disconnected state; and a microprocessor, controlling the switch of the detection switch, calculating the voltage across the corresponding voltage-dividing resistor as a theoretical diagnosis voltage based on the single cell voltage and the switch state of the corresponding switch tube, and judging whether the real-time diagnosis voltage is within the error range of the corresponding theoretical diagnosis voltage, and judging that the corresponding sampling line is in a disconnected state when the judgment result is no, wherein n is a positive integer greater than or equal to 2; A clamp management module, wherein the clamp management module comprises n voltage-stabilizing diodes corresponding to the n single cells respectively, and each of the voltage-stabilizing diodes is connected in series between two corresponding current-limiting resistors or between a corresponding current-limiting resistor and a reference current-limiting resistor.

2. The battery pack sampling line disconnection detection device according to claim 1, characterized in that: in, The voltage acquisition unit includes an operational amplifier, the two input ends of the operational amplifier are respectively connected to the corresponding two current limiting resistors or the corresponding current limiting resistor and the reference current limiting resistor, and the output end is used to transmit the single cell voltage to the microprocessor and the corresponding comparison and judgment unit and to transmit the real-time diagnostic voltage to the microprocessor.

3. The battery pack sampling line disconnection detection device according to claim 2, characterized in that: in, The voltage acquisition unit also includes two resistors corresponding to the two input terminals as differential sampling resistors, and a resistor as an operational amplifier current limiting resistor. The differential sampling resistor is connected in series between the corresponding input terminal and the current limiting resistor or between the corresponding input terminal and the reference current limiting resistor, and the operational amplifier current limiting resistor is connected in series between the output terminal and the corresponding comparison and judgment unit.

4. The battery pack sampling line disconnection detection device according to claim 2, characterized in that: in, The comparison and judgment unit includes a comparator, a negative input terminal of the comparator is connected to the output terminal of the corresponding operational amplifier, a positive input terminal is used to receive the preset reference voltage, and an output terminal of the comparator is connected to the control terminal of the corresponding switch tube.

5. The battery pack sampling line disconnection detection device according to claim 4, characterized in that: in, The comparison and judgment unit further comprises a pull-up resistor, one end of which is connected to the output end of the corresponding comparator, and the other end is used to receive a pull-up voltage.

6. A method for detecting a disconnection of a sampling line of a battery pack, applied to the detection device according to any one of claims 1 to 5, characterized in that: The following steps are involved: Control all detection switches to be in a closed state, collect the voltage across each single cell as the single cell voltage; determine in turn whether the voltage of each single cell is greater than a preset reference voltage, if so, turn off the corresponding switch tube, if not, turn on the corresponding switch tube; Open each of the detection switches in turn and keep the rest of the detection switches in the closed state, collect the voltage across the corresponding voltage-dividing resistor as the real-time diagnostic voltage; calculate the voltage across the corresponding voltage-dividing resistor as the theoretical diagnostic voltage based on the single cell voltage and the corresponding switch state of the switch tube; judge whether the real-time diagnostic voltage is within the error range of the corresponding theoretical diagnostic voltage, and when the judgment result is no, determine that the corresponding sampling line is in a disconnected state.

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