Insulation detection circuit, battery management system and energy storage device

Abstract

The utility model provides an insulation detection circuit, a battery management system and an energy storage device. The circuit comprises a detection switch sub-circuit, an anode insulation detection sub-circuit and a cathode insulation detection sub-circuit. The detection switch sub-circuit is respectively connected with a series resistance circuit between the positive electrode and the negative electrode of a to-be-detected battery pack, a first control pin of the main control chip and a low-voltage ground end, and the positive electrode insulation detection sub-circuit is respectively connected with the positive electrode of the to-be-detected battery pack, the detection switch sub-circuit and a second control pin of the main control chip; the negative electrode insulation detection sub-circuit is connected with the negative electrode of the battery pack to be detected, the detection switch sub-circuit and a third control pin of the main control chip; and a data acquisition pin of the main control chip is connected with an insulation test point on the series resistance circuit. According to the scheme provided by the utility model, the insulation detection architecture is simpler, the detection process is easy to realize, no professional equipment is needed in the detection process, and the detection cost is effectively reduced.

Description

Technical Field

[0001] This utility model relates to the field of insulation testing technology, and in particular to an insulation testing circuit, a battery management system, and an energy storage device. Background Technology

[0002] As the power source for energy storage devices, the safety of the battery pack directly affects the operational safety of the energy storage device. Since the upper and lower shells of the battery pack are directly connected to the main body of the energy storage device, if there is a leakage problem in the battery pack, it will directly affect the personal safety of the operators on the energy storage device. Therefore, it is crucial to test the insulation performance between the high-voltage end and the low-voltage ground end of the battery pack.

[0003] In related technologies, the AC injection method is usually used to detect the insulation between the high-voltage end and the low-voltage ground end. However, this insulation detection scheme requires specialized equipment and a complex calibration process. The insulation detection architecture is cumbersome and the detection cost is high. Utility Model Content

[0004] This invention provides an insulation detection circuit, a battery management system, and an energy storage device to solve the shortcomings of traditional insulation detection schemes, such as cumbersome detection architecture and high detection costs.

[0005] On the one hand, this utility model provides an insulation detection circuit, which is located between the main control chip and the battery pack under test. The circuit includes: a detection switch sub-circuit, a positive electrode insulation detection sub-circuit, and a negative electrode insulation detection sub-circuit.

[0006] The detection switch sub-circuit is connected to the series resistor line between the positive and negative terminals of the battery pack under test, the first control pin of the main control chip, and the low-voltage ground terminal, respectively. The positive electrode insulation detection sub-circuit is connected to the positive terminal of the battery pack under test, the detection switch sub-circuit, and the second control pin of the main control chip, respectively. The negative electrode insulation detection sub-circuit is connected to the negative terminal of the battery pack under test, the detection switch sub-circuit, and the third control pin of the main control chip, respectively. The data acquisition pin of the main control chip is connected to the insulation test point on the series resistor line.

[0007] According to the insulation detection circuit provided by this utility model, the detection switch sub-circuit includes: a reed switch and a first contact switch;

[0008] The first end of the reed switch is connected to the series resistor line between the positive and negative terminals of the battery pack under test. The second end of the reed switch is connected to the first contact switch and the first control pin of the main control chip, respectively. The third end of the reed switch and the first contact switch are both connected to the low-voltage ground terminal. The fourth end of the reed switch is connected to the voltage regulator.

[0009] According to the insulation detection circuit provided by this utility model, the positive electrode insulation detection sub-circuit includes: a first optocoupler switch, a second contact switch, a first voltage divider module, and a second voltage divider module;

[0010] The first terminal of the first optocoupler switch is connected to the first voltage divider module, which is connected to the positive terminal of the battery pack under test. The second terminal of the first optocoupler switch is connected to the second voltage divider module, which is connected to the detection switch sub-circuit. The third terminal of the first optocoupler switch is connected to the second contact switch and the second control pin of the main control chip. The fourth terminal of the first optocoupler switch is connected to a voltage regulator. The second contact switch is also connected to the low-voltage ground terminal.

[0011] According to the insulation detection circuit provided by this utility model, the first voltage divider module includes: a first voltage divider resistor, a second voltage divider resistor, a third voltage divider resistor, and a fourth voltage divider resistor;

[0012] The first voltage divider resistor, the second voltage divider resistor, the third voltage divider resistor, and the fourth voltage divider resistor are connected in series to form a first series branch. One end of the first series branch is connected to the first terminal of the first optocoupler switch, and the other end of the first series branch is connected to the positive terminal of the battery pack under test.

[0013] According to the insulation detection circuit provided by this utility model, the second voltage divider module includes: a fifth voltage divider resistor and a sixth voltage divider resistor;

[0014] The fifth voltage divider resistor and the sixth voltage divider resistor are connected in series to form a second series branch. One end of the second series branch is connected to the second terminal of the first optocoupler switch, and the other end of the second series branch is connected to the detection switch sub-circuit.

[0015] According to the insulation detection circuit provided by this utility model, the negative electrode insulation detection sub-circuit includes: a second optocoupler switch, a third contact switch, a third voltage divider module, and a fourth voltage divider module.

[0016] The first terminal of the second optocoupler switch is connected to the third voltage divider module, which is connected to the negative terminal of the battery pack under test. The second terminal of the second optocoupler switch is connected to the fourth voltage divider module, which is connected to the detection switch sub-circuit. The third terminal of the second optocoupler switch is connected to the third contact switch and the third control pin of the main control chip, respectively. The fourth terminal of the second optocoupler switch is connected to a voltage regulator. The third contact switch is also connected to the low-voltage ground terminal.

[0017] According to the insulation detection circuit provided by this utility model, the third voltage divider module includes: a seventh voltage divider resistor, an eighth voltage divider resistor, a ninth voltage divider resistor, and a tenth voltage divider resistor;

[0018] The seventh voltage divider resistor, the eighth voltage divider resistor, the ninth voltage divider resistor, and the tenth voltage divider resistor are connected in series to form a third series branch. One end of the third series branch is connected to the first terminal of the second optocoupler switch, and the other end of the third series branch is connected to the negative terminal of the battery pack under test.

[0019] According to the insulation detection circuit provided by this utility model, the fourth voltage divider module includes: an eleventh voltage divider resistor and a twelfth voltage divider resistor;

[0020] The eleventh voltage divider resistor and the twelfth voltage divider resistor are connected in series to form a fourth series branch. One end of the fourth series branch is connected to the second terminal of the second optocoupler switch, and the other end of the fourth series branch is connected to the detection switch sub-circuit.

[0021] On the other hand, this utility model also provides a battery management system, including any of the insulation detection circuits described above.

[0022] On the other hand, this utility model also provides an energy storage device, including any of the insulation detection circuits described above or the battery management system described above.

[0023] The insulation detection circuit, battery management system, and energy storage device provided by this utility model, through the setting of a detection switch sub-circuit, a positive electrode insulation detection sub-circuit, and a negative electrode insulation detection sub-circuit, connects the detection switch sub-circuit to the series resistor line between the positive and negative electrodes of the battery pack under test, the first control pin of the main control chip, and the low-voltage ground terminal, respectively. The positive electrode insulation detection sub-circuit is connected to the positive electrode of the battery pack under test, the detection switch sub-circuit, and the second control pin of the main control chip, respectively. The negative electrode insulation detection sub-circuit is connected to the negative electrode of the battery pack under test, the detection switch sub-circuit, and the third control pin of the main control chip, respectively. The data acquisition pin of the main control chip is connected to the insulation test point on the series resistor line. Since the detection switch sub-circuit, positive electrode insulation detection sub-circuit, and negative electrode insulation detection sub-circuit can be controlled by the main control chip to achieve insulation detection between the positive and negative electrodes of the battery pack and the low-voltage ground terminal, the insulation detection architecture is simpler, the detection process is easier to implement, and the detection process does not require specialized equipment, effectively reducing detection costs. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the insulation detection circuit provided in an embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of the detection switch sub-circuit;

[0027] Figure 3 This is a schematic diagram of the positive electrode insulation detection sub-circuit;

[0028] Figure 4 This is a schematic diagram of the negative electrode insulation detection sub-circuit. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0030] The following is combined Figures 1 to 4 This invention describes the detailed solutions for the insulation detection circuit, battery management system, and energy storage device provided in the embodiments of the present invention.

[0031] Figure 1 This is a schematic diagram of the insulation detection circuit provided in an embodiment of the present invention.

[0032] like Figure 1 As shown, this utility model embodiment provides an insulation detection circuit, which is located between the main control chip and the battery pack under test. The circuit specifically includes: a detection switch sub-circuit 110, a positive electrode insulation detection sub-circuit 120, and a negative electrode insulation detection sub-circuit 130.

[0033] The detection switch sub-circuit 110 is connected to the series resistor line between the positive and negative terminals of the battery pack under test, the first control pin IO_ISO_KEY of the main control chip, and the low-voltage ground terminal, respectively. The positive insulation detection sub-circuit 120 is connected to the positive terminal PACK+ of the battery pack under test, the detection switch sub-circuit 110, and the second control pin IO_POS_KEY of the main control chip, respectively. The negative insulation detection sub-circuit 130 is connected to the negative terminal PACK- of the battery pack under test, the detection switch sub-circuit 110, and the third control pin IO_NEG_KEY of the main control chip, respectively. The data acquisition pin ISO_VOTAGE_MSR of the main control chip is connected to the insulation test point T1 on the series resistor line.

[0034] In this embodiment, the detection switch sub-circuit 110 is mainly used to connect its own ground terminal PE_GND to the low-voltage ground terminal after receiving a valid level signal output from the first control pin IO_ISO_KEY. In the insulation detection stage, the positive insulation detection sub-circuit 120 and the negative insulation detection sub-circuit 130 are alternately turned on. That is, when the positive insulation detection sub-circuit 120 is on, the negative insulation detection sub-circuit 130 is off. At this time, the insulation detection loop between the positive terminal PACK+ of the battery pack under test and the low-voltage ground terminal is connected. The first sampling voltage of the insulation test point T1 at this time can be obtained through the data acquisition pin ISO_VOTAGE_MSR of the main control chip, thereby obtaining the first insulation resistance value between the positive terminal PACK+ of the battery pack under test and the low-voltage ground terminal.

[0035] When the negative insulation detection sub-circuit 130 is turned on, the positive insulation detection sub-circuit 120 is turned off. At this time, the insulation detection circuit between the negative PACK- of the battery pack under test and the low-voltage ground terminal is turned on. The second sampling voltage of the insulation test point T1 can be obtained through the data acquisition pin ISO_VOTAGE_MSR of the main control chip, and then the second insulation resistance value between the negative PACK- of the battery pack under test and the low-voltage ground terminal can be obtained. Subsequently, the insulation detection function can be realized using the first insulation resistance value and the second insulation resistance value.

[0036] In one embodiment, see Figure 2 The detection switch sub-circuit specifically includes: reed switch U1 and first contact switch K1.

[0037] The first end of reed switch U1 is connected to the series resistor line between the positive and negative terminals of the battery pack under test. The second end of reed switch U1 is connected to the first contact switch K1 and the first control pin IO_ISO_KEY of the main control chip. The third end of reed switch U1 and the first contact switch K1 are both connected to the low-voltage ground terminal. The fourth end of reed switch U1 is connected to a 5V regulated power supply.

[0038] The reed switch U1 is a magnetic field-operated electrical switch, mainly based on two soft magnetic metal springs to achieve conduction and cutoff. The two metal springs are sealed in a tube with a very small gap between them. When an external magnetic field approaches the two metal springs, the magnetic field generates different polarities near the endpoints of the two metal springs, magnetizing them. As the magnetic force increases, when the magnetic force exceeds the elastic force of the two metal springs themselves, the two metal springs attract each other, realizing the conduction of the reed switch U1. When the external magnetic field moves away, the two metal springs gradually demagnetize, and due to the self-generated elastic force of the metal springs, the two contacts separate, realizing the cutoff of the reed switch U1.

[0039] like Figure 2As shown, a 5V constant voltage source is input to the fourth terminal on the upper left side of reed switch U1, and the first control signal is input to the second terminal on the lower left side by the first control pin IO_ISO_KEY of the main control chip. The first control signal can control the opening and closing state of the first contact switch K1. When the first contact switch K1 is closed, the current generated by the 5V constant voltage source will flow to the low voltage end. Due to the principle of electromagnetism, the two metal springs inside reed switch U1 are attracted together, and reed switch U1 is turned on. At this time, the ground terminal PE_GND of reed switch U1 itself is essentially the same as the low voltage ground terminal.

[0040] like Figure 2 As shown, in this embodiment, the series resistance line between the positive and negative terminals of the battery pack under test is specifically formed by resistors R12, R13, R14, R15, R16, R17 and R18 connected in series. The first end of the reed switch U1 is specifically connected between resistors R15 and R16, and the insulation test point T1 is specifically set between resistors R17 and R18.

[0041] In one embodiment, see Figure 3 The positive electrode insulation detection sub-circuit specifically includes: a first optocoupler switch U2, a second contact switch K2, a first voltage divider module 210, and a second voltage divider module 220.

[0042] The first terminal of the first optocoupler switch U2 is connected to the first voltage divider module 210, which is connected to the positive terminal PACK+ of the battery pack under test. The second terminal of the first optocoupler switch U2 is connected to the second voltage divider module 220, which is connected to the ground terminal PE_GND of the detection switch sub-circuit itself. The third terminal of the first optocoupler switch U2 is connected to the second contact switch K2 and the second control pin IO_POS_KEY of the main control chip. The fourth terminal of the first optocoupler switch U2 is connected to a 5V regulated power supply. The second contact switch K2 is also connected to the low-voltage ground terminal.

[0043] In a specific implementation, see Figure 3 The first voltage divider module 210 specifically includes: a first voltage divider resistor R0, a second voltage divider resistor R1, a third voltage divider resistor R2, and a fourth voltage divider resistor R3.

[0044] The first voltage divider resistor R0, the second voltage divider resistor R1, the third voltage divider resistor R2, and the fourth voltage divider resistor R3 are connected in series to form the first series branch. One end of the first series branch is connected to the first terminal of the first optocoupler switch U2, and the other end of the first series branch is connected to the positive terminal PACK+ of the battery pack under test.

[0045] In a specific implementation, see Figure 3 The second voltage divider module specifically includes: the fifth voltage divider resistor R4 and the sixth voltage divider resistor R5.

[0046] The fifth voltage divider resistor R4 and the sixth voltage divider resistor R5 are connected in series to form the second series branch. One end of the second series branch is connected to the second terminal of the first optocoupler switch U2, and the other end of the second series branch is connected to the ground terminal PE_GND of the detection switch sub-circuit itself.

[0047] In one embodiment, see Figure 4 The negative electrode insulation detection sub-circuit specifically includes: a second optocoupler switch U3, a third contact switch K3, a third voltage divider module 310, and a fourth voltage divider module 320.

[0048] The first terminal of the second optocoupler switch U3 is connected to the third voltage divider module 310, which is connected to the negative terminal PACK- of the battery pack under test. The second terminal of the second optocoupler switch U3 is connected to the fourth voltage divider module 320, which is connected to the ground terminal PE_GND of the detection switch sub-circuit itself. The third terminal of the second optocoupler switch U3 is connected to the third contact switch K3 and the third control pin IO_NEG_KEY of the main control chip. The fourth terminal of the second optocoupler switch U3 is connected to a 5V regulated power supply. The third contact switch K3 is also connected to the low-voltage ground terminal.

[0049] In a specific implementation, see Figure 4 The third voltage divider module 310 specifically includes: the seventh voltage divider resistor R6, the eighth voltage divider resistor R7, the ninth voltage divider resistor R8, and the tenth voltage divider resistor R9.

[0050] The seventh voltage divider resistor R6, the eighth voltage divider resistor R7, the ninth voltage divider resistor R8, and the tenth voltage divider resistor R9 are connected in series to form the third series branch. One end of the third series branch is connected to the first terminal of the second optocoupler switch U3, and the other end of the third series branch is connected to the negative terminal PACK- of the battery pack under test.

[0051] In a specific implementation, see Figure 4 The fourth voltage divider module 320 specifically includes: the eleventh voltage divider resistor R10 and the twelfth voltage divider resistor R11.

[0052] The eleventh voltage divider resistor R10 and the twelfth voltage divider resistor R11 are connected in series to form the fourth series branch. One end of the fourth series branch is connected to the second terminal of the second optocoupler switch U3, and the other end of the fourth series branch is connected to the ground terminal PE_GND of the detection switch sub-circuit itself.

[0053] like Figure 2 As shown, in some embodiments, a current-limiting resistor R19 is also provided between the data acquisition pin ISO_VOTAGE_MSR of the main control chip and the insulation test point T1. The setting of the current-limiting resistor R19 can improve the circuit stability and safety of the voltage acquisition stage.

[0054] The following is combined Figures 1 to 4 The working principle of the insulation detection circuit provided in this embodiment will be explained in detail below:

[0055] First, after the main control chip controls the first contact switch K1 to close, thereby turning on the reed switch U1, when both the second contact switch K2 and the third contact switch K3 are open, the main control chip can acquire the initial feedback voltage U at the insulation test point T1 through the data acquisition pin ISO_VOTAGE_MSR. T1 Let the resistance of the series resistors R12 to R17 in the series resistor line be R. 串 The positive voltage of the battery pack is U PACK+ The negative terminal voltage of the battery pack is U. PACK- The battery pack voltage is U PACK The current through resistor R18 is I. R18 The first insulation resistance from the positive terminal PACK+ of the battery pack to the low-voltage ground is Rp, and the second insulation resistance from the negative terminal PACK- of the battery pack to the low-voltage ground is Rn. The following equation applies:

[0056]

[0057] U PACK =U PACK- +U PACK+ (3)

[0058] Combining equations (1), (2), and (3) above, we can obtain:

[0059]

[0060] Then, while controlling the first contact switch K1 to close, the second contact switch K2 is further controlled to close, and the third contact switch K3 is controlled to close, thereby turning on the first optocoupler switch U2 and turning off the second optocoupler switch U3. At this time, the insulation detection circuit from the positive terminal PACK+ of the battery pack to the low-voltage ground terminal is activated. Based on the resistance values ​​of the multiple voltage divider resistors R0, R1, R2, R3, R4, and R5 between the positive terminal PACK+ of the battery pack and the ground terminal PE_GND of the reed switch U1 itself, and the series resistor R... 串 The voltage divider calculation is performed based on the resistance value of resistor R18, and combined with the first sampled voltage U at the insulation test point T1 at this time. T1 ’ We can obtain the following equation:

[0061]

[0062] Finally, with reed switch U1 closed, the second contact switch K2 is turned off, and the third contact switch K3 is closed, thereby opening the first optocoupler switch U2 and turning on the second optocoupler switch U3. At this time, the insulation detection circuit from the negative terminal PACK- of the battery pack to the low-voltage ground terminal is activated. Based on the resistance values ​​of the multiple voltage divider resistors R6, R7, R8, R9, R10, and R11 between the negative terminal PACK- of the battery pack and the ground terminal PE_GND of the reed switch U1 itself, and the series resistor R... 串 The voltage divider calculation is performed based on the resistance value of resistor R18, and combined with the second sampling voltage U at the insulation test point T1 at this time. T1 The following equation can be obtained:

[0063]

[0064] Subsequently, by combining the above formulas (4) and (5), the first insulation resistance value Rp from the positive terminal PACK+ of the battery pack to the low-voltage ground terminal can be obtained. By combining the above formulas (4) and (6), the second insulation resistance value Rn from the negative terminal PACK- of the battery pack to the low-voltage ground terminal can be obtained. After obtaining the first insulation resistance value Rp and the second insulation resistance value Rn, the above two insulation resistance values ​​can be compared with the preset resistance threshold. If at least one of the first insulation resistance value Rp and the second insulation resistance value Rn is lower than the resistance threshold, it indicates that there is an insulation safety problem at this time.

[0065] It should be noted that this utility model mainly protects the circuit structure of the insulation detection branch between the positive terminal and the low-voltage ground terminal of the battery pack and the insulation detection branch between the negative terminal and the low-voltage ground terminal of the battery pack. The insulation resistance calculation process mainly utilizes the voltage divider principle, which is relatively mature in this field, and is not the improvement scheme that this utility model aims to protect.

[0066] In addition, this utility model embodiment also provides a battery management system, including the insulation detection circuit provided in the above embodiments.

[0067] In addition, this utility model embodiment also provides an energy storage device, including the insulation detection circuit or the battery management system provided in the above embodiments.

[0068] Understandably, energy storage devices can be vehicles, construction machinery, etc.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. An insulation detection circuit, characterized in that, The circuit is located between the main control chip and the battery pack under test, and the circuit includes: a detection switch sub-circuit, a positive electrode insulation detection sub-circuit, and a negative electrode insulation detection sub-circuit; The detection switch sub-circuit is connected to the series resistor line between the positive and negative terminals of the battery pack under test, the first control pin of the main control chip, and the low-voltage ground terminal, respectively. The positive electrode insulation detection sub-circuit is connected to the positive terminal of the battery pack under test, the detection switch sub-circuit, and the second control pin of the main control chip, respectively. The negative electrode insulation detection sub-circuit is connected to the negative terminal of the battery pack under test, the detection switch sub-circuit, and the third control pin of the main control chip, respectively. The data acquisition pin of the main control chip is connected to the insulation test point on the series resistor line.

2. The insulation detection circuit according to claim 1, characterized in that, The detection switch sub-circuit includes: a reed switch and a first contact switch; The first end of the reed switch is connected to the series resistor line between the positive and negative terminals of the battery pack under test. The second end of the reed switch is connected to the first contact switch and the first control pin of the main control chip, respectively. The third end of the reed switch and the first contact switch are both connected to the low-voltage ground terminal. The fourth end of the reed switch is connected to the voltage regulator.

3. The insulation detection circuit according to claim 1, characterized in that, The positive electrode insulation detection sub-circuit includes: a first optocoupler switch, a second contact switch, a first voltage divider module, and a second voltage divider module; The first terminal of the first optocoupler switch is connected to the first voltage divider module, which is connected to the positive terminal of the battery pack under test. The second terminal of the first optocoupler switch is connected to the second voltage divider module, which is connected to the detection switch sub-circuit. The third terminal of the first optocoupler switch is connected to the second contact switch and the second control pin of the main control chip. The fourth terminal of the first optocoupler switch is connected to a voltage regulator. The second contact switch is also connected to the low-voltage ground terminal.

4. The insulation detection circuit according to claim 3, characterized in that, The first voltage divider module includes: a first voltage divider resistor, a second voltage divider resistor, a third voltage divider resistor, and a fourth voltage divider resistor; The first voltage divider resistor, the second voltage divider resistor, the third voltage divider resistor, and the fourth voltage divider resistor are connected in series to form a first series branch. One end of the first series branch is connected to the first terminal of the first optocoupler switch, and the other end of the first series branch is connected to the positive terminal of the battery pack under test.

5. The insulation detection circuit according to claim 3, characterized in that, The second voltage divider module includes: a fifth voltage divider resistor and a sixth voltage divider resistor; The fifth voltage divider resistor and the sixth voltage divider resistor are connected in series to form a second series branch. One end of the second series branch is connected to the second terminal of the first optocoupler switch, and the other end of the second series branch is connected to the detection switch sub-circuit.

6. The insulation detection circuit according to claim 1, characterized in that, The negative electrode insulation detection sub-circuit includes: a second optocoupler switch, a third contact switch, a third voltage divider module, and a fourth voltage divider module; The first terminal of the second optocoupler switch is connected to the third voltage divider module, which is connected to the negative terminal of the battery pack under test. The second terminal of the second optocoupler switch is connected to the fourth voltage divider module, which is connected to the detection switch sub-circuit. The third terminal of the second optocoupler switch is connected to the third contact switch and the third control pin of the main control chip, respectively. The fourth terminal of the second optocoupler switch is connected to a voltage regulator. The third contact switch is also connected to the low-voltage ground terminal.

7. The insulation detection circuit according to claim 6, characterized in that, The third voltage divider module includes: a seventh voltage divider resistor, an eighth voltage divider resistor, a ninth voltage divider resistor, and a tenth voltage divider resistor; The seventh voltage divider resistor, the eighth voltage divider resistor, the ninth voltage divider resistor, and the tenth voltage divider resistor are connected in series to form a third series branch. One end of the third series branch is connected to the first terminal of the second optocoupler switch, and the other end of the third series branch is connected to the negative terminal of the battery pack under test.

8. The insulation detection circuit according to claim 6, characterized in that, The fourth voltage divider module includes: an eleventh voltage divider resistor and a twelfth voltage divider resistor; The eleventh voltage divider resistor and the twelfth voltage divider resistor are connected in series to form a fourth series branch. One end of the fourth series branch is connected to the second terminal of the second optocoupler switch, and the other end of the fourth series branch is connected to the detection switch sub-circuit.

9. A battery management system, characterized in that, Includes the insulation detection circuit as described in any one of claims 1 to 8.

10. An energy storage device, characterized in that, This includes the insulation detection circuit as described in any one of claims 1 to 8 or the battery management system as described in claim 9.

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