Insulation resistance detection method, device and equipment

Abstract

The present application discloses a method, device and equipment for detecting insulation resistance, which relates to the field of circuit design technology, and is used to solve the problem of inaccurate insulation resistance calculation caused by voltage changes during insulation resistance detection in the related technology. The embodiment of the present application can obtain the relevant voltages in the circuit in a steady-state state by determining that the fluctuation range of the first insulation detection voltage is within the first threshold range, and by determining that the fluctuation range of the second insulation detection voltage is within the second threshold range, respectively, to quickly diagnose the situation where the battery pack voltage changes too much, and obtain the relevant data required for calculating the insulation resistance after the voltage stabilizes, thereby avoiding the problem of inaccurate insulation resistance calculation caused by voltage changes during insulation resistance detection, reducing the error of insulation resistance, and improving the detection efficiency and accuracy of the insulation resistance of the target circuit.

Description

Technical Field

[0001] The present application relates to the technical field of power battery insulation resistance detection, and in particular to an insulation resistance detection method, device and equipment. Background Technology

[0002] Currently, there are two methods for testing the insulation resistance of electric vehicles. One is to use the signal injection method for measurement, and the other is to use external resistance switching for measurement. The detection principle of the external resistance measurement circuit is to collect the voltage on the insulation resistance and use simultaneous equations to calculate the insulation resistance of the positive and negative electrodes of the power battery to the vehicle body shell.

[0003] Related technologies During the insulation test, the collected insulation resistance test voltage needs a certain amount of time to stabilize due to the influence of the Y capacitor, so the insulation resistance test process needs a certain amount of time. The larger the insulation resistance or the larger the Y capacitor, the longer the insulation resistance test voltage stabilizes, and the corresponding insulation resistance test cycle is longer. There are two problems encountered during the actual insulation resistance test:

[0004] 1. The collected insulation resistance detection voltage is a voltage division related to the battery pack voltage. Under different charging and discharging conditions of electric vehicles, the battery pack voltage will change with the change of charging and discharging conditions. At this time, the insulation resistance detection voltage will also change in real time, resulting in inaccurate insulation resistance calculation.

[0005] 2. During a cycle of insulation resistance testing, if the insulation resistance suddenly changes (including increasing or decreasing), calculating the insulation resistance according to the normal insulation resistance testing process will also lead to inaccurate insulation resistance calculation.

[0006] Therefore, in view of the defects in the related technologies, providing a method that can overcome the defects in the related technologies has become a concern of the industry. SUMMARY OF THE INVENTION

[0007] The purpose of this application is to provide a method, device and equipment for detecting insulation resistance, so as to solve the problem of inaccurate insulation resistance calculation caused by voltage changes during insulation resistance detection in related technologies.

[0008] In a first aspect, the present application provides an insulation resistance detection method, which is applied to a circuit that uses an unbalanced bridge method to detect insulation resistance, the circuit comprising a power supply, an insulation detection main relay, an insulation detection positive relay, an insulation detection negative relay, a positive terminal resistor, and a negative terminal resistor, the method comprising:

[0009] Receive an insulation detection request, close the insulation detection main relay and obtain the first insulation detection voltage of the negative terminal resistance;

[0010] When the fluctuation range of the first insulation detection voltage is within the first threshold range, it is determined that the first insulation detection voltage reaches a stable state, and the first battery pack voltage across the power supply, the first positive terminal measurement voltage of the positive terminal resistor, and the first negative terminal measurement voltage of the negative terminal resistor are acquired;

[0011] According to the comparison result of the first positive terminal measurement voltage and the first negative terminal measurement voltage, the insulation detection positive relay or the insulation detection negative relay corresponding to the comparison result is closed, and the second insulation detection voltage of the negative terminal resistor is acquired;

[0012] When the fluctuation range of the second insulation detection voltage is within the second threshold range, it is determined that the second insulation detection voltage reaches a stable state, and the second battery pack voltage across the power supply, the second positive terminal measurement voltage of the positive terminal resistor, and the second negative terminal measurement voltage of the negative terminal resistor are acquired;

[0013] According to the first positive terminal measurement voltage, the first negative terminal measurement voltage, the second positive terminal measurement voltage, and the second negative terminal measurement voltage, the insulation resistance is determined.

[0014] In a possible implementation manner, when the fluctuation range of the first insulation detection voltage is within the first threshold range, determining that the first insulation detection voltage reaches a stable state includes:

[0015] Collect the first insulation detection voltage at a step size, and compare the first insulation detection voltage collected at the current step size with the n first insulation detection voltages collected at the previous n step sizes respectively;

[0016] If the difference between the first insulation detection voltage collected at the current step size and any one of the n first insulation detection voltages collected at the previous n step sizes, as a proportion of the first insulation detection voltage collected at the current step size, is less than the first preset proportion and lasts for a time greater than the first preset duration, it is determined that the first insulation detection voltage reaches a stable state.

[0017] In a possible implementation manner, the method further includes:

[0018] When the fluctuation range of the first insulation detection voltage is not within the first threshold range, taking the current time point as a mark, re-acquire the first insulation detection voltage until the fluctuation range of the first insulation detection voltage is within the first threshold range.

[0019] In a possible implementation manner, according to the comparison result of the first positive terminal measurement voltage and the first negative terminal measurement voltage, closing the insulation detection positive relay or the insulation detection negative relay corresponding to the comparison result, and acquiring the second insulation detection voltage of the negative terminal resistor includes:

[0020] If the measured voltage at the first positive terminal is greater than the measured voltage at the first negative terminal, close the positive insulation detection relay;

[0021] If the measured voltage at the first positive terminal is not greater than the measured voltage at the first negative terminal, close the negative insulation detection relay.

[0022] In a possible implementation, when the fluctuation range of the second insulation detection voltage is within the second threshold range, determining that the second insulation detection voltage reaches a stable state includes:

[0023] Collect the second insulation detection voltage at a step size, and compare the second insulation detection voltage collected at the current step size with the n second insulation detection voltages collected at the previous n step sizes respectively;

[0024] If the difference between the second insulation detection voltage collected at the current step size and any one of the n second insulation detection voltages collected at the previous n step sizes, as a proportion of the second insulation detection voltage collected at the current step size, is less than the second preset proportion and lasts for a time greater than the second preset duration, determine that the second insulation detection voltage reaches a stable state.

[0025] In a possible implementation, the method further includes:

[0026] When the fluctuation range of the second insulation detection voltage is not within the second threshold range, return to execute the step of closing the main insulation detection relay and obtaining the first insulation detection voltage.

[0027] In a possible implementation, after obtaining the second battery pack voltage across the power supply, the second positive terminal measured voltage of the positive terminal resistor, and the second negative terminal measured voltage of the negative terminal resistor, the method further includes:

[0028] When the first battery pack voltage is less than the second battery pack voltage, adjust the first positive terminal measured voltage and the first negative terminal measured voltage upward;

[0029] When the first battery pack voltage is greater than the second battery pack voltage, adjust the first positive terminal measured voltage and the first negative terminal measured voltage downward;

[0030] Determine the insulation resistance according to the adjusted first positive terminal measured voltage, the adjusted first negative terminal measured voltage, the second positive terminal measured voltage, and the second negative terminal measured voltage.

[0031] In a possible implementation, adjusting the first positive terminal measured voltage and the first negative terminal measured voltage includes:

[0032] Determine the ratio of the second battery pack voltage to the first battery pack voltage, and use the following formula to determine the adjusted first positive terminal measurement voltage and the adjusted first negative terminal measurement voltage:

[0033]

[0034] where, U c represents the adjusted voltage, U batt2 represents the second battery pack voltage, U batt1 represents the first battery pack voltage, and U represents the voltage before adjustment.

[0035] In a possible implementation manner, it further includes:

[0036] After determining the insulation resistance, disconnect the insulation detection relay in the circuit.

[0037] In a second aspect, the present application provides a device for detecting insulation resistance, which is applied to a circuit for detecting insulation resistance by using an unbalanced bridge method. The circuit includes a power supply, an insulation detection main relay, an insulation detection positive relay, an insulation detection negative relay, a positive terminal resistor, and a negative terminal resistor. The device includes:

[0038] A first insulation detection voltage acquisition module, configured to receive an insulation detection request, close the insulation detection main relay, and acquire the first insulation detection voltage of the negative terminal resistor;

[0039] A first voltage acquisition module, configured to determine that the first insulation detection voltage reaches a stable state when the fluctuation range of the first insulation detection voltage is within a first threshold range, and acquire the first battery pack voltage across the power supply, the first positive terminal measurement voltage of the positive terminal resistor, and the first negative terminal measurement voltage of the negative terminal resistor;

[0040] A voltage comparison module, configured to close the insulation detection positive relay or the insulation detection negative relay corresponding to the comparison result according to the comparison result of the first positive terminal measurement voltage and the first negative terminal measurement voltage, and acquire the second insulation detection voltage of the negative terminal resistor;

[0041] A second voltage acquisition module, configured to determine that the second insulation detection voltage reaches a stable state when the fluctuation range of the second insulation detection voltage is within a second threshold range, and acquire the second battery pack voltage across the power supply, the second positive terminal measurement voltage of the positive terminal resistor, and the second negative terminal measurement voltage of the negative terminal resistor;

[0042] An insulation resistance determination module, configured to determine the insulation resistance according to the first positive terminal measurement voltage, the first negative terminal measurement voltage, the second positive terminal measurement voltage, and the second negative terminal measurement voltage.

[0043] In a possible implementation manner, when the fluctuation range of the first insulation detection voltage is within the first threshold range, it is determined that the first insulation detection voltage reaches a stable state, and the first voltage acquisition module is configured to:

[0044] Collect the first insulation detection voltage according to a step size, and compare the first insulation detection voltage collected in the current step size with the n first insulation detection voltages collected in the previous n step sizes respectively;

[0045] If the difference between the first insulation detection voltage collected in the current step size and any one of the n first insulation detection voltages collected in the previous n step sizes, as a proportion of the first insulation detection voltage collected in the current step size, is less than the first preset proportion and lasts for a time greater than the first preset duration, it is determined that the first insulation detection voltage reaches a stable state.

[0046] In a possible implementation manner, the device is further configured to:

[0047] When the fluctuation range of the first insulation detection voltage is not within the first threshold range, using the current time point as a mark, re-acquire the first insulation detection voltage until the fluctuation range of the first insulation detection voltage is within the first threshold range.

[0048] In a possible implementation manner, according to the comparison result of the first positive terminal measurement voltage and the first negative terminal measurement voltage, close the insulation detection positive relay or the insulation detection negative relay corresponding to the comparison result, and acquire the second insulation detection voltage of the negative terminal resistance. The voltage comparison module is configured to:

[0049] If the first positive terminal measurement voltage is greater than the first negative terminal measurement voltage, close the insulation detection positive relay;

[0050] If the first positive terminal measurement voltage is not greater than the first negative terminal measurement voltage, close the insulation detection negative relay.

[0051] In a possible implementation manner, when the fluctuation range of the second insulation detection voltage is within the second threshold range, it is determined that the second insulation detection voltage reaches a stable state, and the second voltage acquisition module is configured to:

[0052] Collect the second insulation detection voltage according to a step size, and compare the second insulation detection voltage collected in the current step size with the n second insulation detection voltages collected in the previous n step sizes respectively;

[0053] If the ratio of the difference between the second insulation detection voltage collected in the current step and any one of the n second insulation detection voltages collected in the previous n steps to the second insulation detection voltage collected in the current step is less than the second preset ratio and lasts for a duration greater than the second preset duration, it is determined that the second insulation detection voltage reaches a stable state.

[0054] In a possible implementation manner, the device is further configured to:

[0055] When the fluctuation range of the second insulation detection voltage is not within the second threshold range, return to execute the step of closing the insulation detection main relay and obtaining the first insulation detection voltage.

[0056] In a possible implementation manner, after obtaining the second battery pack voltage across the power supply, the second positive terminal measurement voltage of the positive terminal resistor, and the second negative terminal measurement voltage of the negative terminal resistor, the device is further configured to:

[0057] When the first battery pack voltage is less than the second battery pack voltage, adjust the first positive terminal measurement voltage and the first negative terminal measurement voltage upward;

[0058] When the first battery pack voltage is greater than the second battery pack voltage, adjust the first positive terminal measurement voltage and the first negative terminal measurement voltage downward;

[0059] Determine the insulation resistance according to the adjusted first positive terminal measurement voltage, the adjusted first negative terminal measurement voltage, the second positive terminal measurement voltage, and the second negative terminal measurement voltage.

[0060] In a possible implementation manner, when adjusting the first positive terminal measurement voltage and the first negative terminal measurement voltage, the device is configured to:

[0061] Determine the ratio of the second battery pack voltage to the first battery pack voltage, and use the following formula to determine the adjusted first positive terminal measurement voltage and the adjusted first negative terminal measurement voltage:

[0062]

[0063] where U c represents the adjusted voltage, U batt2 represents the second battery pack voltage, U batt1 represents the first battery pack voltage, and U represents the voltage before adjustment.

[0064] In a possible implementation manner, it further includes:

[0065] After determining the insulation resistance, disconnect the insulation detection relay in the circuit.

[0066] In a third aspect, the present application provides a detection device for insulation resistance, comprising:

[0067] a processor and a memory;

[0068] The display is used to display an interface;

[0069] The memory is used to store executable instructions of the processor;

[0070] The processor is connected to a circuit for detecting insulation resistance by using the unbalanced bridge method, collects relevant parameters of the circuit, and is configured to execute the instructions to implement the insulation resistance detection method according to any one of the above first aspects.

[0071] In a fourth aspect, the present application provides a computer-readable storage medium, when the instructions in the computer-readable storage medium are executed by a detection device for insulation resistance, enabling the detection device for insulation resistance to execute the insulation resistance detection method according to any one of the above first aspects.

[0072] In a fifth aspect, the present application provides a computer program product, comprising a computer program:

[0073] When the computer program is executed by a processor, it implements the insulation resistance detection method according to any one of the above first aspects.

[0074] The technical solutions provided by the embodiments of the present application at least bring the following beneficial effects:

[0075] In the embodiments of the present application, an insulation detection request is received, the main insulation detection relay is closed, and the first insulation detection voltage of the negative terminal resistance is obtained; when the fluctuation range of the first insulation detection voltage is within the first threshold range, it is determined that the first insulation detection voltage reaches a stable state, and the first battery pack voltage across the power supply, the first positive terminal measurement voltage of the positive terminal resistance, and the first negative terminal measurement voltage of the negative terminal resistance are obtained. Then, according to the comparison result of the first positive terminal measurement voltage and the first negative terminal measurement voltage, the insulation detection positive relay or the insulation detection negative relay corresponding to the comparison result is closed, and the second insulation detection voltage of the negative terminal resistance is obtained. Then, when the fluctuation range of the second insulation detection voltage is within the second threshold range, it is determined that the second insulation detection voltage reaches a stable state, and the second battery pack voltage across the power supply, the second positive terminal measurement voltage of the positive terminal resistance, and the second negative terminal measurement voltage of the negative terminal resistance are obtained. Finally, the insulation resistance is determined according to the first positive terminal measurement voltage, the first negative terminal measurement voltage, the second positive terminal measurement voltage, and the second negative terminal measurement voltage. In summary, in the embodiments of the present application, when it is determined that the fluctuation range of the first insulation detection voltage is within the first threshold range and when it is determined that the fluctuation range of the second insulation detection voltage is within the second threshold range, the relevant voltages in the stable circuit can be obtained respectively, quickly diagnosing the situation where the battery pack voltage changes too much, avoiding the problem that the insulation resistance calculation is inaccurate due to voltage changes during the insulation resistance detection process, reducing the error of the insulation resistance, and improving the detection efficiency and accuracy of the insulation resistance of the target circuit.

[0076] Other features and advantages of the present application will be described in the following specification, and, in part, will be obvious from the specification, or will be understood by implementing the present application. The objectives and other advantages of the present application can be achieved and obtained by the structures specifically pointed out in the written specification, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0077] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required to be used in the embodiments of the present application. Obviously, the following introduced drawings are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0078] Figure 1 It is a schematic diagram of a circuit applied to the insulation resistance detection using the unbalanced bridge method provided by the embodiments of the present application;

[0079] Figure 2 It is a schematic diagram of the overall flow of the insulation resistance detection method provided by the embodiments of the present application;

[0080] Figure 3 It is a schematic diagram of the flow of step 202 provided by the embodiments of the present application;

[0081] Figure 4 It is a schematic flowchart of step 204 provided by an embodiment of the present application;

[0082] Figure 5 It is a schematic structural diagram of a detection device for insulation resistance provided by an embodiment of the present application;

[0083] Figure 6 It is a schematic structural diagram of a detection equipment for insulation resistance provided by an embodiment of the present application. Specific embodiments

[0084] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Among them, the described embodiments are some but not all of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts fall within the scope of protection of the present application.

[0085] Moreover, in the description of the embodiments of the present application, unless otherwise specified, " / " means "or". For example, A / B may mean A or B; "and / or" in the text is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of the present application, "a plurality of" means two or more than two.

[0086] Hereinafter, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as implying or indicating relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the embodiments of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more than two.

[0087] Taking the circuit for insulation resistance detection using the unbalanced bridge method as an example, 3 relays need to be driven. The circuit for insulation resistance detection is as Figure 1 shown and includes the following:

[0088] 1) The measured resistances are as follows:

[0089] R1: The resistance at the positive end of the measuring device.

[0090] R2: The resistance at the negative end of the measuring device.

[0091] Ro_P: The standard known resistance for calculating the insulation resistance at the main positive end.

[0092] Ro_N: Standard known resistance for calculating insulation resistance at the main negative terminal.

[0093] RIns_P: Calculated value of insulation resistance at the main positive terminal.

[0094] RIns_N: Calculated value of insulation resistance at the main negative terminal.

[0095] 2) The relays are as follows:

[0096] Switch Main: Main insulation detection relay.

[0097] Switch Pos: Positive terminal insulation detection relay.

[0098] Switch Neg: Negative terminal insulation detection relay.

[0099] 3) The measured parameters are as follows:

[0100] Upos: Measured voltage at the positive terminal.

[0101] Uneg: Measured voltage at the negative terminal.

[0102] 4) In the related technology, the steps for measuring insulation resistance are as follows:

[0103] Close the main insulation detection relay (Switch Main) to obtain the measured voltage at the positive terminal (Upos) and the measured voltage at the negative terminal (Uneg);

[0104] Judge the magnitude relationship between Upos and Uneg. If Upos > Uneg, close the positive terminal insulation detection relay (Switch Pos), connect R1 and Ro_P to the circuit, and then re-obtain the measured voltage at the positive terminal (UposwithR1) and the measured voltage at the negative terminal (UnegwithR1);

[0105] Otherwise, if Upos ≤ Uneg, close the negative terminal insulation detection relay (Switch Neg), connect R2 and Ro_N to the circuit, and then re-obtain the measured voltage at the positive terminal (UposwithR2) and the measured voltage at the negative terminal (UnegwithR2);

[0106] Calculate the insulation resistance RIns_P at the main positive terminal and the insulation resistance RIns_N at the main negative terminal according to the formula.

[0107] The calculation formula for the insulation resistance RIns_P at the main positive terminal is shown in the following formula (1):

[0108]

[0109] Among them, R P represents the insulation resistance at the main positive terminal, R NOThe standard known resistance representing the insulation resistance calculated at the main negative terminal, U Bat Represents the battery pack voltage, U NR Represents the re - acquired negative - terminal measured voltage, U N Represents the negative - terminal measured voltage.

[0110] If the calculated insulation resistance of the main positive terminal is selected for correction to reflect a more realistic insulation resistance, the correction formula (2) is as follows:

[0111]

[0112] Where, R PC Represents the corrected insulation resistance of the main positive terminal, R P Represents the insulation resistance of the main positive terminal, R 1 Represents the resistance at the positive terminal of the measuring device.

[0113] The calculation formula for the insulation resistance RIns_N of the main negative terminal is as shown in formula (3) below:

[0114]

[0115] Where, R N Represents the insulation resistance of the main negative terminal, R PO Represents the standard known resistance for calculating the insulation resistance of the main positive terminal, U Bat Represents the battery pack voltage, U PR Represents the re - acquired positive - terminal measured voltage, U P Represents the positive - terminal measured voltage.

[0116] If the calculated insulation resistance of the main negative terminal is selected for correction to reflect the real insulation resistance, the correction formula (4) is as follows:

[0117]

[0118] Where, R PC Represents the corrected insulation resistance of the main negative terminal, R P Represents the insulation resistance of the main negative terminal, R 1 Represents the resistance at the negative terminal of the measuring device.

[0119] In the above related technologies, there are the following problems in obtaining the insulation detection voltage: 1) Determine the insulation detection process and the non-insulation detection process. If the battery pack voltage changes too much during these two processes, terminate the insulation detection process; 2) During the insulation detection process, regardless of whether the resistance changes or not, calculate the insulation resistance according to the normal process. The above method determines the insulation detection process and the non-insulation detection process and can interrupt the insulation detection process in a timely manner. However, in the two steps of obtaining the relevant voltage during the insulation detection process, the influence of the battery pack voltage change on the calculation accuracy of the insulation resistance is not considered; in addition, if the insulation resistance suddenly changes during the insulation detection process, it will cause a change in the insulation detection voltage. At this time, the related technology calculates the insulation resistance according to the normal process, which will lead to too large a deviation in the calculated insulation resistance.

[0120] In view of this, the present application provides a method, device and equipment for detecting insulation resistance to overcome the defects of the related technologies.

[0121] The inventive concept of the present application can be summarized as follows: Receive an insulation detection request, close the insulation detection main relay and obtain the first insulation detection voltage of the negative terminal resistance; when the fluctuation range of the first insulation detection voltage is within the first threshold range, determine that the first insulation detection voltage reaches a stable state, and obtain the first battery pack voltage across the power supply, the first positive terminal measurement voltage of the positive terminal resistance, and the first negative terminal measurement voltage of the negative terminal resistance. Then, according to the comparison result of the first positive terminal measurement voltage and the first negative terminal measurement voltage, close the insulation detection positive relay or the insulation detection negative relay corresponding to the comparison result, and obtain the second insulation detection voltage of the negative terminal resistance. Then, when the fluctuation range of the second insulation detection voltage is within the second threshold range, determine that the second insulation detection voltage reaches a stable state, and obtain the second battery pack voltage across the power supply, the second positive terminal measurement voltage of the positive terminal resistance, and the second negative terminal measurement voltage of the negative terminal resistance. Finally, determine the insulation resistance according to the first positive terminal measurement voltage, the first negative terminal measurement voltage, the second positive terminal measurement voltage and the second negative terminal measurement voltage. In summary, the embodiments of the present application can obtain the relevant voltages in the stable circuit by determining that the fluctuation range of the first insulation detection voltage is within the first threshold range and determining that the fluctuation range of the second insulation detection voltage is within the second threshold range, quickly diagnose the situation where the battery pack voltage changes too much, avoid the problem of inaccurate insulation resistance calculation caused by voltage change during the insulation resistance detection process, reduce the error of the insulation resistance, and improve the detection efficiency and accuracy of the insulation resistance of the target circuit.

[0122] After introducing the main inventive idea of the embodiments of the present application, the following briefly introduces the application scenarios applicable to the technical solutions of the embodiments of the present application. It should be noted that the application scenarios introduced below are only used to illustrate the embodiments of the present application rather than to limit them. In specific implementation, the technical solutions provided by the embodiments of the present application can be flexibly applied according to actual needs.

[0123] To facilitate the understanding of the insulation resistance detection method provided by the embodiments of the present application, the following further describes it in conjunction with the accompanying drawings.

[0124] In a possible implementation manner, the present application provides an insulation resistance detection method, which is applied to a circuit for detecting insulation resistance by using the unbalanced bridge method. The circuit is as Figure 1 shown, and includes a power supply, an insulation detection main relay, an insulation detection positive relay, an insulation detection negative relay, a positive terminal resistor, and a negative terminal resistor. The overall flowchart of this method is as Figure 2 shown and includes the following content:

[0125] In step 201, an insulation detection request is received, the insulation detection main relay is closed, and the first insulation detection voltage of the negative terminal resistor is obtained.

[0126] In a possible implementation manner, first, the low-voltage power on the BMS (Battery Manage System) is initialized first, and it is judged whether there is an insulation detection request. If there is no insulation detection request at this time, the insulation detection main relay has no action. Otherwise, if there is an insulation detection request, it enters the normal insulation detection process, that is, the insulation detection main relay is closed and the first insulation detection voltage of the negative terminal resistor is obtained.

[0127] In step 202, when the fluctuation range of the first insulation detection voltage is within the first threshold range, it is determined that the first insulation detection voltage reaches a stable state, and the first battery pack voltage across the power supply, the first positive terminal measurement voltage of the positive terminal resistor, and the first negative terminal measurement voltage of the negative terminal resistor are obtained.

[0128] In a possible implementation manner, in step 202, when the fluctuation range of the first insulation detection voltage is within the first threshold range, it is determined that the first insulation detection voltage reaches a stable state. Its flowchart is as Figure 3 shown and includes the following content:

[0129] In step 301, the first insulation detection voltage is collected according to a step size, and the first insulation detection voltage collected at the current step size is respectively compared with the n first insulation detection voltages collected at the previous n step sizes.

[0130] In step 302, if the difference between the first insulation detection voltage collected at the current step size and any one of the n first insulation detection voltages collected at the previous n step sizes, and the proportion of the first insulation detection voltage collected at the current step size is less than the first preset proportion, and the duration is greater than the first preset duration, it is determined that the first insulation detection voltage reaches a stable state.

[0131] For example, obtain the first insulation detection voltage collected at the current step size and the n first insulation detection voltages collected at the previous n step sizes, and determine the difference between the first insulation detection voltage collected at the current step size and one of the first insulation detection voltages collected at the previous n step sizes. The ratio of this difference to the first insulation detection voltage collected at the current step size is less than the first preset ratio. For example, the first insulation detection voltage collected at the current step size is 100V, and the difference from one of the n first insulation detection voltages collected at the previous n step sizes is 0.01V. Moreover, if the first preset ratio determined in this application is four-thousandths, it is determined that the ratio of this difference to the first insulation detection voltage collected at the current step size is less than the first preset ratio. Then, starting from the current step, the timing flag is set. And if the duration during which the ratio of the difference to the first insulation detection voltage collected at the current step size is less than the first preset ratio exceeds a certain value (i.e., the first preset duration), such as the time corresponding to 3 step sizes, the embodiments of this application determine that the first insulation detection voltage reaches a stable state. Otherwise, if the difference is greater than the first preset ratio, the timing flag will not be set, or if the timing flag is set and the duration is too short and does not exceed the first preset duration, the flag bit will be cleared. All the above situations indicate that the first insulation detection voltage does not reach a stable state.

[0132] After determining that the first insulation detection voltage reaches a stable state, or after determining that the closing time of the insulation detection positive relay reaches the maximum value, the current battery pack voltage (i.e., the first battery pack voltage) can be obtained and latched. At the same time, the voltage values Upos (i.e., the first positive terminal measurement voltage of the positive terminal resistance) and Uneg (i.e., the first negative terminal measurement voltage of the negative terminal resistance) used to calculate the insulation resistance are obtained and latched. Otherwise, if the insulation detection voltage is unstable and the closing time of the insulation detection main relay does not reach the maximum value, the above voltage values will not be obtained.

[0133] It should be added that in a possible implementation manner, when the fluctuation range of the first insulation detection voltage is not within the first threshold range, that is, the difference between the first insulation detection voltage collected at the current step size and one of the first insulation detection voltages collected at the previous n step sizes, and the ratio of this difference to the first insulation detection voltage collected at the current step size is not within the first preset ratio range, then taking the current time point as a mark, the first insulation detection voltage is re-obtained until the fluctuation range of the first insulation detection voltage is within the first threshold range. By obtaining the voltage in a stable state, the most accurate effect of the calculated value of the insulation resistance is achieved.

[0134] In step 203, according to the comparison result of the first positive terminal measurement voltage and the first negative terminal measurement voltage, the insulation detection positive relay or the insulation detection negative relay corresponding to the comparison result is closed, and the second insulation detection voltage of the negative terminal resistance is obtained.

[0135] In a possible implementation manner, in step 203, according to the comparison result of the first positive terminal measurement voltage and the first negative terminal measurement voltage, close the insulation detection positive relay or the insulation detection negative relay corresponding to the comparison result, and obtain the second insulation detection voltage of the negative terminal resistor, including the following two cases:

[0136] If the first positive terminal measurement voltage is greater than the first negative terminal measurement voltage, close the insulation detection positive relay;

[0137] If the first positive terminal measurement voltage is not greater than the first negative terminal measurement voltage, close the insulation detection negative relay.

[0138] In step 204, when the fluctuation range of the second insulation detection voltage is within the second threshold range, determine that the second insulation detection voltage reaches a stable state, and obtain the second battery pack voltage across the power supply, the second positive terminal measurement voltage of the positive terminal resistor, and the second negative terminal measurement voltage of the negative terminal resistor.

[0139] In a possible implementation manner, based on the same principle as step 202, in step 204, when the fluctuation range of the second insulation detection voltage is within the second threshold range, determine that the second insulation detection voltage reaches a stable state, and its flowchart is as Figure 4 shown, including the following content:

[0140] In step 401, collect the second insulation detection voltage at a step size, and compare the second insulation detection voltage collected at the current step size with the n second insulation detection voltages collected at the previous n step sizes respectively.

[0141] In step 402, if the difference between the second insulation detection voltage collected at the current step size and any one of the n second insulation detection voltages collected at the previous n step sizes, and the proportion of the difference in the second insulation detection voltage collected at the current step size is less than the second preset proportion, and the duration is greater than the second preset duration, determine that the second insulation detection voltage reaches a stable state.

[0142] It should be noted that the method for determining that the second insulation detection voltage reaches a stable state in step 204 is similar to that in step 202. When the fluctuation range of the second insulation detection voltage is within the second threshold range, that is, the difference between the second insulation detection voltage collected at the current step size and one of the second insulation detection voltages collected at the previous n step sizes, and the proportion of the difference in the first insulation detection voltage collected at the current step size is within the second preset proportion range, then determine that the second insulation detection voltage reaches a stable state, which is not elaborated in this embodiment of the present application.

[0143] In a possible implementation manner, when the fluctuation range of the second insulation detection voltage is not within the second threshold range, return to the step of closing the insulation detection main relay and obtaining the first insulation detection voltage. That is, if it is determined that the second insulation detection voltage is unstable, the result of the insulation resistance is invalid. Therefore, it is necessary to interrupt the insulation detection process in a timely manner, re-obtain the insulation detection voltage, and calculate the insulation resistance. Alternatively, when the change value of the judged second insulation detection voltage suddenly becomes larger during the non-operation process of the relay (including the insulation detection main relay, the insulation detection positive relay, and the insulation detection negative relay) and is greater than a certain threshold (such as the third threshold), it indicates that the insulation resistance has suddenly changed. At this time, it is invalid to continue calculating the insulation resistance according to the process. Therefore, it is necessary to interrupt the current insulation detection process in a timely manner and start a new round of insulation detection process, re-obtain the insulation detection voltage, and calculate the insulation resistance.

[0144] The embodiment of the present application can timely identify the change of the insulation resistance within an insulation detection cycle, and can interrupt and re-perform a new insulation detection process in a timely manner, which not only ensures the rapid diagnosis of the insulation detection, but also ensures the accuracy of the insulation detection.

[0145] In step 205, determine the insulation resistance according to the first positive terminal measurement voltage, the first negative terminal measurement voltage, the second positive terminal measurement voltage, and the second negative terminal measurement voltage.

[0146] In a possible implementation manner, the insulation resistance includes the main positive terminal insulation resistance and the main negative terminal insulation resistance. After obtaining the first positive terminal measurement voltage, the first negative terminal measurement voltage, the second positive terminal measurement voltage, and the second negative terminal measurement voltage, determine the main positive terminal insulation resistance and the main negative terminal insulation resistance respectively according to the above formula (1) and formula (3), that is, obtain the insulation resistance of the power battery.

[0147] In a possible implementation manner, after obtaining the second battery pack voltage across the power supply, the second positive terminal measurement voltage of the positive terminal resistance, and the second negative terminal measurement voltage of the negative terminal resistance, and before obtaining the insulation resistance, the embodiment of the present application will also adjust the first positive terminal measurement voltage and the first negative terminal measurement voltage, including the following content:

[0148] When the first battery pack voltage is less than the second battery pack voltage, adjust the first positive terminal measurement voltage and the first negative terminal measurement voltage upward;

[0149] When the first battery pack voltage is greater than the second battery pack voltage, adjust the first positive terminal measurement voltage and the first negative terminal measurement voltage downward;

[0150] According to the adjusted first positive terminal measurement voltage, the adjusted first negative terminal measurement voltage, the second positive terminal measurement voltage, and the second negative terminal measurement voltage, determine the main positive terminal insulation resistance and the main negative terminal insulation resistance respectively according to the above formula (1) and formula (3), and finally, determine the insulation resistance.

[0151] In a possible implementation, adjusting the first positive terminal measurement voltage and the first negative terminal measurement voltage specifically includes the following:

[0152] Determine the ratio of the second battery pack voltage to the first battery pack voltage, and use the following formula (5) to determine the adjusted first positive terminal measurement voltage and the adjusted first negative terminal measurement voltage:

[0153]

[0154] where U c represents the adjusted voltage, U batt2 represents the second battery pack voltage, U batt1 represents the first battery pack voltage, and U represents the voltage before adjustment. This application can ensure the calculation accuracy of the insulation detection resistance through the above process of correcting the insulation detection voltage in the dynamic situation where the battery pack voltage changes too much.

[0155] It should be added that after determining the insulation resistance in the embodiment of this application, all insulation detection relays in the circuit will be disconnected, and then the next insulation detection process can be carried out.

[0156] In summary, when the embodiment of this application determines that the fluctuation range of the first insulation detection voltage is within the first threshold range and the fluctuation range of the second insulation detection voltage is within the second threshold range, it can respectively obtain the relevant voltages in the circuit in a stable state, quickly diagnose the situation where the battery pack voltage changes too much, avoid the problem of inaccurate calculation of the insulation resistance caused by voltage changes during the insulation resistance detection process, reduce the error of the insulation resistance, and improve the detection efficiency and accuracy of the insulation resistance of the target circuit.

[0157] Based on the same inventive concept, this application provides a device for detecting insulation resistance, which is applied to a circuit for detecting insulation resistance by using the unbalanced bridge method. The circuit includes a power supply, an insulation detection main relay, an insulation detection positive relay, an insulation detection negative relay, a positive terminal resistor, and a negative terminal resistor. As Figure 5 shown, the device 500 includes:

[0158] A first insulation detection voltage acquisition module 501, configured to receive an insulation detection request, close the insulation detection main relay, and acquire the first insulation detection voltage of the negative terminal resistor;

[0159] A first voltage acquisition module 502, configured to determine that the first insulation detection voltage reaches a stable state when the fluctuation range of the first insulation detection voltage is within the first threshold range, and acquire the first battery pack voltage across the power supply, the first positive terminal measurement voltage of the positive terminal resistor, and the first negative terminal measurement voltage of the negative terminal resistor;

[0160] The voltage comparison module 503 is configured to close the insulation detection positive relay or the insulation detection negative relay corresponding to the comparison result according to the comparison result of the first positive terminal measured voltage and the first negative terminal measured voltage, and obtain the second insulation detection voltage of the negative terminal resistor;

[0161] The second voltage acquisition module 504 is configured to determine that the second insulation detection voltage reaches a stable state when the fluctuation range of the second insulation detection voltage is within the second threshold range, and obtain the second battery pack voltage across the power supply, the second positive terminal measured voltage of the positive terminal resistor, and the second negative terminal measured voltage of the negative terminal resistor;

[0162] The insulation resistance determination module 505 is configured to determine the insulation resistance according to the first positive terminal measured voltage, the first negative terminal measured voltage, the second positive terminal measured voltage, and the second negative terminal measured voltage.

[0163] In a possible implementation manner, when the fluctuation range of the first insulation detection voltage is within the first threshold range, it is determined that the first insulation detection voltage reaches a stable state, and the first voltage acquisition module is configured to:

[0164] Collect the first insulation detection voltage according to a step size, and compare the first insulation detection voltage collected at the current step size with the n first insulation detection voltages collected at the previous n step sizes respectively;

[0165] If the difference between the first insulation detection voltage collected at the current step size and any one of the n first insulation detection voltages collected at the previous n step sizes accounts for a proportion less than the first preset proportion of the first insulation detection voltage collected at the current step size and lasts for a time greater than the first preset duration, it is determined that the first insulation detection voltage reaches a stable state.

[0166] In a possible implementation manner, the device is further configured to:

[0167] When the fluctuation range of the first insulation detection voltage is not within the first threshold range, mark the current time point and re-acquire the first insulation detection voltage until the fluctuation range of the first insulation detection voltage is within the first threshold range.

[0168] In a possible implementation manner, according to the comparison result of the first positive terminal measured voltage and the first negative terminal measured voltage, the insulation detection positive relay or the insulation detection negative relay corresponding to the comparison result is closed, and the second insulation detection voltage of the negative terminal resistor is obtained. The voltage comparison module is configured to:

[0169] If the first positive terminal measured voltage is greater than the first negative terminal measured voltage, close the insulation detection positive relay;

[0170] If the first positive terminal measurement voltage is not greater than the first negative terminal measurement voltage, close the insulation detection negative relay.

[0171] In a possible implementation, when the fluctuation range of the second insulation detection voltage is within the second threshold range, it is determined that the second insulation detection voltage reaches a stable state. The second voltage acquisition module is configured as follows:

[0172] Collect the second insulation detection voltage at a step size, and compare the second insulation detection voltage collected at the current step size with the n second insulation detection voltages collected at the previous n step sizes respectively;

[0173] If the difference between the second insulation detection voltage collected at the current step size and any one of the n second insulation detection voltages collected at the previous n step sizes, as a proportion of the second insulation detection voltage collected at the current step size, is less than the second preset proportion and lasts for a time greater than the second preset duration, it is determined that the second insulation detection voltage reaches a stable state.

[0174] In a possible implementation, the device is further configured as follows:

[0175] When the fluctuation range of the second insulation detection voltage is not within the second threshold range, return to execute the step of closing the insulation detection main relay and acquiring the first insulation detection voltage.

[0176] In a possible implementation, after acquiring the second battery pack voltage across the power supply, the second positive terminal measurement voltage of the positive terminal resistor, and the second negative terminal measurement voltage of the negative terminal resistor, the device is further configured as follows:

[0177] When the first battery pack voltage is less than the second battery pack voltage, adjust the first positive terminal measurement voltage and the first negative terminal measurement voltage upward;

[0178] When the first battery pack voltage is greater than the second battery pack voltage, adjust the first positive terminal measurement voltage and the first negative terminal measurement voltage downward;

[0179] Determine the insulation resistance based on the adjusted first positive terminal measurement voltage, the adjusted first negative terminal measurement voltage, the second positive terminal measurement voltage, and the second negative terminal measurement voltage.

[0180] In a possible implementation, when adjusting the first positive terminal measurement voltage and the first negative terminal measurement voltage, the device is configured as follows:

[0181] Determine the ratio of the second battery pack voltage to the first battery pack voltage, and use the following formula to determine the adjusted first positive terminal measurement voltage and the adjusted first negative terminal measurement voltage:

[0182]

[0183] Among them, U c represents the adjusted voltage, and U batt2 represents the voltage of the second battery pack, and U batt1 represents the voltage of the first battery pack. U represents the voltage before adjustment.

[0184] Next, refer to Figure 6 to describe the insulation resistance detection device 130 according to this embodiment of the present application. Figure 6 The displayed insulation resistance detection device 130 is merely an example and should not impose any limitations on the functions and usage scope of the embodiments of the present application.

[0185] As Figure 6 shown, the insulation resistance detection device 130 is presented in the form of a general electronic device. The components of the insulation resistance detection device 130 may include, but are not limited to: the above-mentioned at least one processor 131, the above-mentioned at least one memory 132, and a bus 133 connecting different system components (including the memory 132 and the processor 131).

[0186] The bus 133 represents one or more of several types of bus structures, including a memory bus or a memory controller, a peripheral bus, a processor, or a local bus using any bus structure in a variety of bus structures.

[0187] The memory 132 may include a readable medium in the form of volatile memory, such as a random access memory (RAM) 1321 and / or a cache memory 1322, and may further include a read-only memory (ROM) 1323.

[0188] The memory 132 may further include a program / utility 1325 having a set (at least one) of program modules 1324. Such program modules 1324 include, but are not limited to: an operating system, one or more application programs, other program modules, and program data. Each or some combination of these examples may include the implementation of a network environment.

[0189] The insulation resistance detection device 130 can also communicate with one or more external devices 134 (such as keyboards, pointing devices, etc.), and can also communicate with one or more devices that enable users to interact with the insulation resistance detection device 130, and / or communicate with any device (such as routers, modems, etc.) that enables the insulation resistance detection device 130 to communicate with one or more other electronic devices. Such communication can be carried out through the input / output (I / O) interface 135. Moreover, the insulation resistance detection device 130 can also communicate with one or more networks (such as local area networks (LANs), wide area networks (WANs), and / or public networks, such as the Internet) through the network adapter 136. As shown in the figure, the network adapter 136 communicates with other modules of the insulation resistance detection device 130 through the bus 133. It should be understood that although not shown in the figure, other hardware and / or software modules can be used in combination with the insulation resistance detection device 130, including but not limited to: microcode, device drivers, redundant processors, external disk drive arrays, RAID systems, tape drives, and data backup storage systems, etc.

[0190] In an exemplary embodiment, the present application also provides a computer-readable storage medium including instructions, such as the memory 132 including instructions, and the above instructions can be executed by the processor 131 of the insulation resistance detection device 130 to complete the above insulation resistance detection method. Optionally, the computer-readable storage medium can be a non-transitory computer-readable storage medium. For example, the non-transitory computer-readable storage medium can be ROM, random access memory (RAM), CD-ROM, magnetic tape, floppy disk, and optical data storage devices, etc.

[0191] In an exemplary embodiment, a computer program product is also provided, including a computer program, and when the computer program is executed by the processor 131, it implements the insulation resistance detection method provided by the present application.

[0192] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memory, CD-ROM, optical memory, etc.) containing computer-usable program code.

[0193] This application is described with reference to the flowcharts and / or block diagrams of methods, apparatus (systems), and computer program products according to the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, as well as the combination of flows and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, such that the instructions executed by the processor of the computer or other programmable data processing device produce a means for implementing the functions specified in one flow Figure 1 one flow or multiple flows and / or blocks Figure 1 or multiple blocks.

[0194] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the computer-readable memory produce a manufactured article including an instruction means that implements the functions specified in one flow Figure 1 one flow or multiple flows and / or blocks Figure 1 or multiple blocks.

[0195] These computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one flow Figure 1 one flow or multiple flows and / or blocks Figure 1 or multiple blocks.

[0196] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalent technologies, this application is also intended to include these modifications and variations.

Claims

1. A method for detecting insulation resistance, characterized in that: The circuit includes a power supply, an insulation detection main relay, an insulation detection positive relay, an insulation detection negative relay, a positive terminal resistor, and a negative terminal resistor. The method includes: Receiving an insulation detection request, closing an insulation detection main relay and obtaining a first insulation detection voltage of a negative terminal resistor; When the fluctuation range of the first insulation detection voltage is within the first threshold range, determine that the first insulation detection voltage reaches a stable state, and obtain a first battery pack voltage at both ends of the power supply, a first positive end measurement voltage of the positive terminal resistor, and a first negative end measurement voltage of the negative terminal resistor; According to a comparison result of the first positive terminal measurement voltage and the first negative terminal measurement voltage, closing the insulation detection positive relay or the insulation detection negative relay corresponding to the comparison result, and obtaining a second insulation detection voltage of the negative terminal resistance; When the fluctuation range of the second insulation detection voltage is within the second threshold range, determine that the second insulation detection voltage reaches a stable state, and obtain a second battery pack voltage at both ends of the power supply, a second positive terminal measurement voltage of the positive terminal resistor, and a second negative terminal measurement voltage of the negative terminal resistor; An insulation resistance is determined based on the first positive terminal measured voltage, the first negative terminal measured voltage, the second positive terminal measured voltage, and the second negative terminal measured voltage.

2. The method according to claim 1, characterized in that When the fluctuation range of the first insulation detection voltage is within a first threshold range, determining that the first insulation detection voltage reaches a stable state includes: Collecting the first insulation detection voltage according to the step length, and comparing the first insulation detection voltage collected at the current step length with the n first insulation detection voltages collected at the previous n step lengths; If the difference between the first insulation detection voltage collected at the current step and any one of the n first insulation detection voltages collected at the previous n steps accounts for a proportion of the first insulation detection voltage collected at the current step that is less than a first preset proportion, and the duration is greater than a first preset time length, it is determined that the first insulation detection voltage has reached a stable state.

3. The method according to claim 1, characterized in that The method further comprises: When the fluctuation range of the first insulation detection voltage is not within the first threshold range, the first insulation detection voltage is reacquired with the current time point as a mark until the fluctuation range of the first insulation detection voltage is within the first threshold range.

4. The method according to claim 1, characterized in that: According to a comparison result of the first positive terminal measurement voltage and the first negative terminal measurement voltage, closing an insulation detection positive relay or an insulation detection negative relay corresponding to the comparison result, and obtaining a second insulation detection voltage of the negative terminal resistance, including: If the measured voltage at the first positive terminal is greater than the measured voltage at the first negative terminal, closing the insulation detection positive relay; If the measured voltage at the first positive terminal is not greater than the measured voltage at the first negative terminal, the insulation detection negative relay is closed.

5. The method according to claim 1, characterized in that When the fluctuation range of the second insulation detection voltage is within a second threshold range, determining that the second insulation detection voltage reaches a stable state includes: Collecting the second insulation detection voltage according to the step length, and comparing the second insulation detection voltage collected at the current step length with the n second insulation detection voltages collected at the previous n step lengths; If the difference between the second insulation detection voltage collected at the current step and any second insulation detection voltage among the n second insulation detection voltages collected at the previous n steps accounts for a proportion of the second insulation detection voltage collected at the current step that is less than a second preset proportion, and the duration is greater than a second preset time length, it is determined that the second insulation detection voltage has reached a stable state.

6. The method according to claim 4, characterized in that The method further comprises: When the fluctuation range of the second insulation detection voltage is not within the second threshold range, the process returns to the step of closing the insulation detection main relay and acquiring the first insulation detection voltage.

7. The method according to claim 1, characterized in that After obtaining a second battery pack voltage at both ends of the power source, a second positive end measurement voltage of the positive terminal resistor, and a second negative end measurement voltage of the negative terminal resistor, the method further includes: When the first battery pack voltage is less than the second battery pack voltage, upwardly adjusting the first positive terminal measurement voltage and the first negative terminal measurement voltage; When the first battery pack voltage is greater than the second battery pack voltage, downwardly adjusting the first positive terminal measurement voltage and the first negative terminal measurement voltage; The insulation resistance is determined according to the adjusted first positive terminal measurement voltage, the adjusted first negative terminal measurement voltage, the second positive terminal measurement voltage, and the second negative terminal measurement voltage.

8. The method according to claim 7, characterized in that Adjusting the first positive terminal measurement voltage and the first negative terminal measurement voltage includes: Determine the ratio of the second battery pack voltage to the first battery pack voltage, and use the following formula to determine the adjusted first positive terminal measurement voltage and the adjusted first negative terminal measurement voltage: Among them, U c Indicates the adjusted voltage, U batt2 represents the voltage of the second battery pack, U batt1 represents the first battery pack voltage, and U represents the voltage before adjustment.

9. The method according to any one of claims 1 to 8, characterized in that: Also includes: After determining the insulation resistance, disconnect the insulation detection main relay in the circuit.

10. An insulation resistance detection device, characterized in that: A circuit for insulation resistance detection using an unbalanced bridge method, the circuit comprising a power supply, an insulation detection main relay, an insulation detection positive relay, an insulation detection negative relay, a positive terminal resistor, and a negative terminal resistor, the device comprising: A first insulation detection voltage acquisition module is configured to receive an insulation detection request, close the insulation detection main relay and obtain a first insulation detection voltage of the negative terminal resistor; A first voltage acquisition module is configured to determine that the first insulation detection voltage reaches a stable state when the fluctuation range of the first insulation detection voltage is within a first threshold range, and to acquire a first battery pack voltage at both ends of the power supply, a first positive terminal measurement voltage of the positive terminal resistor, and a first negative terminal measurement voltage of the negative terminal resistor; A voltage comparison module is configured to close the insulation detection positive relay or the insulation detection negative relay corresponding to the comparison result according to the comparison result of the first positive terminal measurement voltage and the first negative terminal measurement voltage, and obtain a second insulation detection voltage of the negative terminal resistance; A second voltage acquisition module is configured to determine that the second insulation detection voltage reaches a stable state when the fluctuation range of the second insulation detection voltage is within a second threshold range, and obtain a second battery pack voltage at both ends of the power supply, a second positive terminal measurement voltage of the positive terminal resistor, and a second negative terminal measurement voltage of the negative terminal resistor; The insulation resistance determination module is configured to determine the insulation resistance according to the first positive terminal measurement voltage, the first negative terminal measurement voltage, the second positive terminal measurement voltage and the second negative terminal measurement voltage.

11. An insulation resistance detection device, characterized in that: include: Processor and memory; The memory is used to store the processor executable instructions; The processor is connected to a circuit that uses an unbalanced bridge method to detect insulation resistance, collects parameters related to the circuit, and is configured to execute the instructions to implement the insulation resistance detection method according to any one of claims 1 to 9.

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