A battery insulation troubleshooting method and device

Abstract

The application discloses a battery insulation fault troubleshooting method and device, comprising: obtaining a measurement voltage between a measurement end and a vehicle body ground end. According to the measurement voltage, a preselected battery insulation fault position is determined. When the negative electrode of the insulation detection tool is connected to the vehicle body ground end and the positive electrode of the insulation detection tool is connected to the preselected battery insulation fault position, a measurement DC voltage and a preselected measurement fault insulation value are obtained. When the negative electrode of the insulation detection tool is connected to the vehicle body ground end and the positive electrode of the insulation detection tool is connected to the battery measurement position, a calculated DC voltage between the preselected battery insulation fault position and the vehicle body ground end and a measurement resistance value are obtained. When the measurement DC voltage, the calculated DC voltage, the preselected measurement fault insulation value and the measurement resistance value meet a preset condition, the preselected battery insulation fault position is determined as the battery insulation fault position, and the battery fault insulation value is determined as the preselected measurement fault insulation value. Through the method, the battery insulation fault can be accurately and quickly investigated and positioned.

Description

Technical Field

[0001] This application relates to the field of electric vehicle technology, and in particular to a method and apparatus for troubleshooting battery insulation faults. Background Technology

[0002] With the rapid development of new energy vehicles, the power batteries in these vehicles need to undergo insulation fault inspection to prevent the risk of electric shock and short circuit fire.

[0003] Currently, traditional insulation fault diagnosis methods rely on professional technicians to inspect battery insulation and pinpoint the fault to the battery module. However, modern power batteries are de-emphasizing the module concept, with battery cells directly connected to the battery pack tray or vehicle chassis. In this context, traditional insulation fault diagnosis methods are no longer applicable. Summary of the Invention

[0004] To address the aforementioned technical problems, this application provides a method and apparatus for troubleshooting battery insulation faults, which can be used to accurately and quickly troubleshoot and locate battery insulation faults.

[0005] To achieve the above objectives, the technical solutions provided in this application are as follows:

[0006] This application provides a method for troubleshooting battery insulation faults, the method comprising:

[0007] Obtain the measurement voltage between the measuring end and the vehicle grounding end; the measuring end is a first end; the first end is sequentially the battery negative terminal, the positive terminals inside each battery in the direction of increasing potential, and the battery positive terminal; or, the measuring end is a second end, the second end is sequentially the battery positive terminal, the positive terminals inside each battery in the direction of decreasing potential, and the battery negative terminal;

[0008] Based on the measured voltage, the location of the pre-selected battery insulation fault is determined;

[0009] When the negative terminal of the insulation testing tool is connected to the vehicle body grounding terminal and the positive terminal of the insulation testing tool is connected to the pre-selected battery insulation fault location, the measured DC voltage between the pre-selected battery insulation fault location and the vehicle body grounding terminal is obtained, as well as the pre-selected measured fault insulation value between the pre-selected battery insulation fault location and the vehicle body grounding terminal; the fault insulation value is the insulation fault resistance value.

[0010] When the negative terminal of the insulation testing tool is connected to the vehicle body grounding terminal and the positive terminal of the insulation testing tool is connected to the battery measurement position, the calculated DC voltage and measured resistance value between the pre-selected battery insulation fault position and the vehicle body grounding terminal are obtained; the measured resistance value is the displayed resistance value of the insulation testing tool.

[0011] When the measured DC voltage, the calculated DC voltage, the pre-selected measured fault insulation value, and the measured resistance value meet preset conditions, the pre-selected battery insulation fault location is determined as the battery insulation fault location, and the battery fault insulation value is determined as the pre-selected measured fault insulation value.

[0012] Optionally, when the positive electrode inside the battery is the positive electrode of the battery cell;

[0013] The step of determining the pre-selected battery insulation fault location based on the measured voltage includes:

[0014] When the measuring end is the first end, when the measuring voltage changes from negative to positive, the pre-selected battery insulation fault location is determined to be the positive terminal position of the battery cell corresponding to when the measuring voltage changes from negative to positive;

[0015] When the measuring terminal is the second terminal, when the measuring voltage changes from positive to negative, the pre-selected battery insulation fault location is determined to be the positive terminal position of the battery cell corresponding to when the measuring voltage changes from negative to positive.

[0016] Optionally, when the positive electrode inside the battery is the positive electrode of the internal module of the battery;

[0017] The step of determining the pre-selected battery insulation fault location based on the measured voltage includes:

[0018] When the measuring end is the first end, the target module is determined when the measuring voltage changes from negative to positive; the target module is the module corresponding to the positive terminal position of the battery module when the measuring voltage changes from negative to positive.

[0019] Obtain the target module cell voltage between the measurement terminal inside the target module and the vehicle body grounding terminal; the measurement terminal inside the target module is a third terminal or a fourth terminal; the third terminal is, in sequence, the negative terminal of the target module, the positive terminal of each cell inside the target module in the direction of increasing potential, and the positive terminal of the target module; the fourth terminal is, in sequence, the positive terminal of the target module, the positive terminal of each cell inside the target module in the direction of decreasing potential, and the negative terminal of the target module;

[0020] Based on the target module cell voltage, the location of the pre-selected battery insulation fault is determined.

[0021] Optionally, when the positive electrode inside the battery is the positive electrode of the internal module of the battery;

[0022] The step of determining the pre-selected battery insulation fault location based on the measured voltage includes:

[0023] When the measuring terminal is the second terminal, the target module is determined when the measuring voltage changes from positive to negative; the target module is the module corresponding to the positive terminal position of the battery module when the measuring voltage changes from positive to negative.

[0024] Obtain the target module cell voltage between the measurement terminal inside the target module and the vehicle body grounding terminal; the measurement terminal inside the target module is a third terminal or a fourth terminal; the third terminal is, in sequence, the negative terminal of the target module, the positive terminal of each cell inside the target module in the direction of increasing potential, and the positive terminal of the target module; the fourth terminal is, in sequence, the positive terminal of the target module, the positive terminal of each cell inside the target module in the direction of decreasing potential, and the negative terminal of the target module;

[0025] Based on the target module cell voltage, the location of the pre-selected battery insulation fault is determined.

[0026] Optionally, the preset condition is that the ratio of the measured resistance value to the pre-selected measured fault insulation value is equal to the ratio of the measured DC voltage to the calculated DC voltage.

[0027] Optionally, when the negative terminal of the insulation testing tool is connected to the vehicle body grounding terminal and the positive terminal of the insulation testing tool is connected to the battery measurement location, obtaining the calculated DC voltage and measured resistance value between the pre-selected battery insulation fault location and the vehicle body grounding terminal includes:

[0028] When the negative terminal of the insulation testing tool is connected to the grounding terminal of the vehicle body and the positive terminal of the insulation testing tool is connected to the battery measurement position, the measured resistance value is obtained;

[0029] Obtain the pressure difference between the pre-selected battery insulation fault location and the battery measurement location;

[0030] Based on the differential pressure value and the measured DC voltage, the calculated DC voltage between the pre-selected battery insulation fault location and the vehicle body grounding terminal is obtained.

[0031] This application embodiment also provides a battery insulation fault diagnosis device, the device comprising:

[0032] The first acquisition unit is used to acquire the measurement voltage between the measurement terminal and the vehicle ground terminal; the measurement terminal is a first terminal; the first terminal is sequentially the battery negative terminal, the positive terminals inside each battery in the direction of increasing potential, and the battery positive terminal; or, the measurement terminal is a second terminal, the second terminal is sequentially the battery positive terminal, the positive terminals inside each battery in the direction of decreasing potential, and the battery negative terminal.

[0033] The first determining unit is used to determine the location of the pre-selected battery insulation fault based on the measured voltage.

[0034] The second acquisition unit is used to acquire, when the negative terminal of the insulation testing tool is connected to the vehicle grounding terminal and the positive terminal of the insulation testing tool is connected to the preselected battery insulation fault location, the measured DC voltage between the preselected battery insulation fault location and the vehicle grounding terminal, and the preselected measured fault insulation value between the preselected battery insulation fault location and the vehicle grounding terminal; the fault insulation value is the insulation fault resistance value.

[0035] The third acquisition unit is used to acquire the calculated DC voltage and measured resistance value between the pre-selected battery insulation fault location and the vehicle grounding terminal when the negative terminal of the insulation detection tool is connected to the vehicle grounding terminal and the positive terminal of the insulation detection tool is connected to the battery measurement location; the measured resistance value is the displayed resistance value of the insulation detection tool.

[0036] The second determining unit is used to determine the pre-selected battery insulation fault location as the battery insulation fault location and to determine the battery fault insulation value as the pre-selected battery insulation fault insulation value when the measured DC voltage, the calculated DC voltage, the pre-selected measured fault insulation value and the measured resistance value meet preset conditions.

[0037] Optionally, when the positive electrode inside the battery is the positive electrode of the battery cell;

[0038] The first determining unit includes:

[0039] The first determining subunit is used to determine the pre-selected battery insulation fault location as the positive electrode location of the battery cell corresponding to the change of the measured voltage from negative to positive when the measuring terminal is the first terminal.

[0040] The second determining subunit is used to determine the pre-selected battery insulation fault location as the positive electrode position of the battery cell corresponding to the change of the measured voltage from negative to positive when the measuring terminal is the second terminal.

[0041] Optionally, when the positive electrode inside the battery is the positive electrode of the internal module of the battery;

[0042] The first determining unit includes:

[0043] The third determining subunit is used to determine the target module when the measured voltage changes from negative to positive when the measuring terminal is the first terminal; the target module is the module corresponding to the positive terminal position of the battery module when the measured voltage changes from negative to positive.

[0044] The first acquisition subunit is used to acquire the target module cell voltage between the measurement terminal inside the target module and the vehicle body grounding terminal; the measurement terminal inside the target module is a third terminal or a fourth terminal; the third terminal is, in sequence, the negative terminal of the target module, the positive terminal of each cell inside the target module in the direction of increasing potential, and the positive terminal of the target module; the fourth terminal is, in sequence, the positive terminal of the target module, the positive terminal of each cell inside the target module in the direction of decreasing potential, and the negative terminal of the target module;

[0045] The fourth determining subunit is used to determine the location of the pre-selected battery insulation fault based on the target module cell voltage.

[0046] Optionally, when the positive electrode inside the battery is the positive electrode of the internal module of the battery;

[0047] The first determining unit includes:

[0048] The fifth determining subunit is used to determine the target module when the measured voltage changes from positive to negative when the measuring terminal is the second terminal; the target module is the module corresponding to the positive terminal position of the battery module when the measured voltage changes from positive to negative.

[0049] The second acquisition subunit is used to acquire the target module cell voltage between the measurement terminal inside the target module and the vehicle body grounding terminal; the measurement terminal inside the target module is a third terminal or a fourth terminal; the third terminal is, in sequence, the negative terminal of the target module, the positive terminal of each cell inside the target module in the direction of increasing potential, and the positive terminal of the target module; the fourth terminal is, in sequence, the positive terminal of the target module, the positive terminal of each cell inside the target module in the direction of decreasing potential, and the negative terminal of the target module;

[0050] The sixth determining subunit is used to determine the location of the pre-selected battery insulation fault based on the target module cell voltage.

[0051] As can be seen from the above technical solution, this application has the following beneficial effects:

[0052] This application provides a method and apparatus for troubleshooting battery insulation faults. The method includes: acquiring a measured voltage between a measuring end and a vehicle body grounding terminal. The measuring end is a first end, which sequentially comprises the battery negative terminal, the internal positive terminals of each battery in the direction of increasing potential, and the battery positive terminal. Alternatively, the measuring end is a second end, which sequentially comprises the battery positive terminal, the internal positive terminals of each battery in the direction of decreasing potential, and the battery negative terminal. Based on the measured voltage, a pre-selected battery insulation fault location is determined. When the negative terminal of the insulation detection tool is connected to the vehicle body grounding terminal and the positive terminal of the insulation detection tool is connected to the pre-selected battery insulation fault location, a measured DC voltage between the pre-selected battery insulation fault location and the vehicle body grounding terminal, and a pre-selected measured fault insulation value between the pre-selected battery insulation fault location and the vehicle body grounding terminal are acquired. The fault insulation value is the insulation fault resistance value. When the negative terminal of the insulation detection tool is connected to the vehicle body grounding terminal and the positive terminal of the insulation detection tool is connected to the battery measuring location, a calculated DC voltage and a measured resistance value between the pre-selected battery insulation fault location and the vehicle body grounding terminal are acquired. The measured resistance value is the displayed resistance value of the insulation detection tool. When the measured DC voltage, calculated DC voltage, pre-selected measured fault insulation value, and measured resistance value meet preset conditions, the pre-selected battery insulation fault location is determined as the battery insulation fault location, and the battery fault insulation value is determined as the pre-selected measured fault insulation value. The battery insulation fault troubleshooting method provided in this application embodiment can accurately and quickly troubleshoot and locate battery insulation faults. Attached Figure Description

[0053] To more clearly illustrate the technical solutions in the embodiments of this application 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 application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0054] Figure 1 A flowchart illustrating a battery insulation fault diagnosis method provided in this application embodiment;

[0055] Figure 2a This application provides a schematic diagram of a battery insulation fault troubleshooting process.

[0056] Figure 2b This is a schematic diagram illustrating another battery insulation fault troubleshooting process provided in an embodiment of this application.

[0057] Figure 2c This is a schematic diagram illustrating another battery insulation fault troubleshooting process provided in an embodiment of this application.

[0058] Figure 2d This is a schematic diagram illustrating another battery insulation fault troubleshooting process provided in an embodiment of this application.

[0059] Figure 3 This is a schematic diagram of a battery insulation fault diagnosis device provided in an embodiment of this application. Detailed Implementation

[0060] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the embodiments of this application will be further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0061] To facilitate understanding and explanation of the technical solutions provided in the embodiments of this application, the background technology of the embodiments of this application will be introduced below.

[0062] Insulation is defined as the separation of conductive components with different electrical potentials in electrical products. In the field of new energy vehicles, it refers to separating high-voltage live components from the chassis (body). Therefore, insulation failure can easily lead to electric shock, short circuits, and fires.

[0063] Currently, when insulation faults occur in the power batteries of new energy vehicles, the traditional solution is for specially trained technicians to troubleshoot the problem. After a series of operations involving high voltage, the fault can be roughly located to the module. The entire troubleshooting process consumes a lot of labor and time costs and carries a high risk. In addition, current power batteries have de-emphasized the module concept, with cells directly connected to the battery pack tray or the vehicle chassis. Therefore, the traditional solution is no longer suitable for troubleshooting insulation faults.

[0064] Based on this, embodiments of this application provide a method and apparatus for troubleshooting battery insulation faults. The method includes: acquiring a measured voltage between a measuring end and a vehicle body grounding terminal. The measuring end is a first end, which sequentially comprises the battery negative terminal, the internal positive terminals of each battery in the direction of increasing potential, and the battery positive terminal. Alternatively, the measuring end is a second end, which sequentially comprises the battery positive terminal, the internal positive terminals of each battery in the direction of decreasing potential, and the battery negative terminal. Based on the measured voltage, a pre-selected battery insulation fault location is determined. When the negative terminal of the insulation testing tool is connected to the vehicle body grounding terminal and the positive terminal of the insulation testing tool is connected to the pre-selected battery insulation fault location, a measured DC voltage between the pre-selected battery insulation fault location and the vehicle body grounding terminal, and a pre-selected measured fault insulation value between the pre-selected battery insulation fault location and the vehicle body grounding terminal are acquired. The fault insulation value is the insulation fault resistance value. When the negative terminal of the insulation testing tool is connected to the vehicle body grounding terminal and the positive terminal of the insulation testing tool is connected to the battery measuring location, a calculated DC voltage and a measured resistance value between the pre-selected battery insulation fault location and the vehicle body grounding terminal are acquired. The measured resistance value is the displayed resistance value of the insulation testing tool. When the measured DC voltage, calculated DC voltage, pre-selected measured fault insulation value, and measured resistance value meet the preset conditions, the pre-selected battery insulation fault location is determined as the battery insulation fault location, and the battery fault insulation value is determined as the pre-selected measured fault insulation value.

[0065] To facilitate understanding of the technical solutions provided in the embodiments of this application, the battery insulation fault diagnosis method provided in the embodiments of this application will be described below with reference to the accompanying drawings. See also Figure 1 , Figure 1 A flowchart of a battery insulation fault diagnosis method provided in this application embodiment is shown below. Figure 1 As shown, the method includes steps S101-S105:

[0066] S101: Obtain the measurement voltage between the measuring terminal and the vehicle ground terminal; the measuring terminal is the first terminal; the first terminal is sequentially the battery negative terminal, the positive terminals inside each battery in the direction of increasing potential, and the battery positive terminal; or, the measuring terminal is the second terminal, the second terminal is sequentially the battery positive terminal, the positive terminals inside each battery in the direction of decreasing potential, and the battery negative terminal.

[0067] When troubleshooting battery insulation faults, first obtain the voltage measurement between the measuring terminal and the vehicle body grounding terminal. The vehicle body grounding terminal is the vehicle's electrical chassis (body). The measuring terminal can be either the first terminal or the second terminal. When the measuring terminal is the first terminal, it sequentially corresponds to the battery negative terminal, the internal positive terminals of each battery in the direction of increasing potential, and the battery positive terminal. When the measuring terminal is the second terminal, it sequentially corresponds to the battery positive terminal, the internal positive terminals of each battery in the direction of decreasing potential, and the battery negative terminal.

[0068] It should be noted that the battery pack contains multiple series-connected modules, and each module contains multiple battery cells. This battery pack structure includes the battery positive terminal, the battery negative terminal, and the positive terminals of each module in the high-voltage section of the battery, with each module containing the positive terminal of each battery cell. The battery positive terminal is the point of highest potential in the high-voltage section of the battery, and the battery negative terminal is the point of lowest potential in the high-voltage section of the battery.

[0069] For clarity, see [link to documentation]. Figure 2a , Figure 2a This is a schematic diagram illustrating a battery insulation fault troubleshooting process provided in an embodiment of this application. Figure 2a As shown in the figure, the power battery (i.e. Figure 2a The battery pack (in the diagram) contains a power battery, which includes a positive terminal and a negative terminal. Assuming the actual location of the battery insulation fault is as shown in the figure, to determine this fault location, it is necessary to first obtain the voltage between the measuring terminal and the vehicle body grounding terminal. In some implementations, a voltage measuring device is used to measure the voltage between the measuring terminal and the vehicle body grounding terminal. For example, a multimeter is used as the voltage measuring device.

[0070] The following description uses the measuring end as an example to illustrate the process of obtaining the voltage between the measuring end and the vehicle grounding terminal. Specifically, the voltage is obtained sequentially from the battery negative terminal, the positive terminals inside each battery in the direction of increasing potential, and the voltage between the battery positive terminal and the vehicle grounding terminal. The voltage between the measuring end and the vehicle grounding terminal is collectively referred to as the measuring voltage.

[0071] See Figure 2a , Figure 2a This is a schematic diagram of a battery insulation fault troubleshooting process provided in an embodiment of this application. Figure 2a This demonstrates how to use a multimeter to determine the connection between the battery negative terminal and the vehicle body ground terminal (i.e., ...). Figure 2a The voltage between the battery and the chassis. Specifically, adjust the measuring device (e.g., a multimeter) to the appropriate range, connect the positive terminal of the measuring device (e.g., the red probe of the multimeter) to the negative terminal of the battery, and the negative terminal of the measuring device (e.g., the black probe of the multimeter) to the chassis, and measure the voltage between the negative terminal of the battery and the ground terminal of the vehicle body. Due to the internal resistance of the measuring device, a stable voltage reading can be obtained. Due to the existence of battery insulation faults, leakage current will occur, which... Figure 2a As we know, leakage current flows from the negative terminal to the positive terminal of the measuring device, so the final measured voltage between the battery negative terminal and the vehicle body ground terminal is negative. It is understandable that the measured voltage between the battery positive terminal and the vehicle body ground terminal is positive.

[0072] in addition, Figure 2a Relays N and P are used to separate the battery pack from the high-voltage load.

[0073] See Figure 2b , Figure 2b This is a schematic diagram of another battery insulation fault troubleshooting process provided in an embodiment of this application. Figure 2b This demonstrates how to use a multimeter to obtain the connection between the positive terminal inside each battery and the vehicle ground terminal in the direction of increasing potential (i.e., ...). Figure 2b The voltage between the electrical chassis (in the middle). Figure 2b The positive terminal of the measuring device (e.g., a multimeter) is connected to the positive terminal of one of the internal positive terminals of each battery in the direction of increasing potential. In practice, the negative terminal of the measuring device is connected to the chassis, and the positive terminal is adjusted so that it sequentially crosses over the internal positive terminals of each battery for measurement. Because the measurement is performed in the direction of increasing potential, the voltage measured between each internal positive terminal of a battery and the vehicle's ground terminal should be higher by a fixed value than the voltage measured in the previous measurement. Figure 2b It can be seen that, Figure 2b If the positive terminal of the measuring device is connected across the insulation fault location, leakage current will flow from the positive terminal to the negative terminal of the measuring device. Figure 2b The voltage measured between the positive terminal of the measuring device and the grounding terminal of the vehicle body is positive.

[0074] S102: Determine the location of the pre-selected battery insulation fault based on the measured voltage.

[0075] Based on the measured voltage, the location of the insulation fault can be preliminarily determined, that is, the location of the pre-selected battery insulation fault can be determined.

[0076] Specifically, by Figure 2a and Figure 2b It can be seen that when the measuring terminal is the first terminal, the measured voltage will change between positive and negative values ​​around the location of the insulation fault. That is, when the measuring terminal is the first terminal, the insulation fault location can be preliminarily determined to be where the measured voltage changes from negative to positive; that is, the pre-selected battery insulation fault location is where the measured voltage changes from negative to positive. In actual operation, the measurement can be stopped when the measured voltage changes from negative to positive. Conversely, when the measuring terminal is the second terminal, the insulation fault location can be preliminarily determined to be where the measured voltage changes from positive to negative; that is, the pre-selected battery insulation fault location is where the measured voltage changes from positive to negative.

[0077] In this embodiment, based on the internal structure of the power battery (i.e., battery pack), the positive electrode inside each battery can be either the module positive electrode or the cell positive electrode. When the positive electrode inside each battery is the module positive electrode, measurements are first performed on a module-by-module basis, and the judgment process and the conditions for stopping the measurement remain unchanged. Specifically, battery insulation faults can first be located to the module, and then the same method can be used inside the module to locate the cell. When the positive electrode inside each battery is the cell positive electrode, the voltage can be directly measured, and when the sign of the measured voltage changes, the cell can be directly located.

[0078] In specific implementation, when the positive terminal inside the battery is the positive terminal of the battery cell, the pre-selected location of the battery insulation fault is determined based on the measured voltage, including:

[0079] When the measuring end is the first end, when the measuring voltage changes from negative to positive, the pre-selected battery insulation fault location is determined to be the positive terminal position of the battery cell corresponding to when the measuring voltage changes from negative to positive;

[0080] When the measuring terminal is the second terminal, when the measuring voltage changes from positive to negative, the pre-selected battery insulation fault location is determined as the positive terminal position of the battery cell corresponding to the change of the measuring voltage from negative to positive.

[0081] Furthermore, when the positive terminal inside the battery is the positive terminal of the battery module, the pre-selected battery insulation fault location is determined based on the measured voltage, including:

[0082] When the measuring terminal is the first terminal, the target module is determined when the measured voltage changes from negative to positive; the target module is the module corresponding to the positive terminal position of the battery module when the measured voltage changes from negative to positive.

[0083] Obtain the target module cell voltage between the measurement terminal inside the target module and the vehicle body ground terminal; the measurement terminal inside the target module is the third terminal or the fourth terminal; the third terminal is, in sequence, the negative terminal of the target module, the positive terminal of each cell inside the target module in the direction of increasing potential, and the positive terminal of the target module; the fourth terminal is, in sequence, the positive terminal of the target module, the positive terminal of each cell inside the target module in the direction of decreasing potential, and the negative terminal of the target module;

[0084] Based on the target module cell voltage, determine the location of the pre-selected battery insulation fault.

[0085] Among these steps, determining the pre-selected battery insulation fault location based on the target module cell voltage includes:

[0086] When the measurement terminal in the target module is the third terminal, if the cell voltage of the target module changes from negative to positive, the pre-selected battery insulation fault location is determined to be the positive terminal position of the cell in the target module when the cell voltage of the target module changes from negative to positive.

[0087] When the measurement terminal in the target module is the fourth terminal, if the cell voltage of the target module changes from positive to negative, the pre-selected battery insulation fault location is determined to be the positive terminal position of the cell in the target module when the cell voltage changes from negative to positive.

[0088] In addition, when the positive terminal inside the battery is the positive terminal of the battery module, determining the pre-selected battery insulation fault location based on the measured voltage also includes:

[0089] When the measuring terminal is the second terminal, the target module is determined when the measured voltage changes from positive to negative; the target module is the module corresponding to the positive terminal position of the battery module when the measured voltage changes from positive to negative.

[0090] Obtain the target module cell voltage between the measurement terminal inside the target module and the vehicle body ground terminal; the measurement terminal inside the target module is the third terminal or the fourth terminal; the third terminal is, in sequence, the negative terminal of the target module, the positive terminal of each cell inside the target module in the direction of increasing potential, and the positive terminal of the target module; the fourth terminal is, in sequence, the positive terminal of the target module, the positive terminal of each cell inside the target module in the direction of decreasing potential, and the negative terminal of the target module;

[0091] Based on the target module cell voltage, determine the location of the pre-selected battery insulation fault.

[0092] Among these steps, determining the pre-selected battery insulation fault location based on the target module cell voltage includes:

[0093] When the measurement terminal in the target module is the third terminal, if the cell voltage of the target module changes from negative to positive, the pre-selected battery insulation fault location is determined to be the positive terminal position of the cell in the target module when the cell voltage of the target module changes from negative to positive.

[0094] When the measurement terminal in the target module is the fourth terminal, if the cell voltage of the target module changes from positive to negative, the pre-selected battery insulation fault location is determined to be the positive terminal position of the cell in the target module when the cell voltage changes from negative to positive.

[0095] By using steps S101 and S102, the location of the insulation faulty cell can be preliminarily located, thus determining the pre-selected battery insulation fault location. The subsequent step requires determining the actual battery insulation fault location and obtaining the actual fault insulation value.

[0096] S103: When the negative terminal of the insulation testing tool is connected to the vehicle grounding terminal and the positive terminal of the insulation testing tool is connected to the pre-selected battery insulation fault location, the measured DC voltage between the pre-selected battery insulation fault location and the vehicle grounding terminal, as well as the pre-selected measured fault insulation value between the pre-selected battery insulation fault location and the vehicle grounding terminal are obtained; the fault insulation value is the insulation fault resistance value.

[0097] After determining the pre-selected battery insulation fault location, it is necessary to confirm whether the pre-selected battery insulation fault location is the actual battery insulation fault location.

[0098] Connect the negative terminal of the insulation testing tool to the vehicle grounding terminal, and the positive terminal of the insulation testing tool to the pre-selected battery insulation fault location. Obtain the measured DC voltage between the pre-selected battery insulation fault location and the vehicle grounding terminal, as well as the pre-selected measured fault insulation value between the pre-selected battery insulation fault location and the vehicle grounding terminal; the fault insulation value is the insulation fault resistance value.

[0099] Specifically, as an example, see Figure 2c , Figure 2c This is a schematic diagram of another battery insulation fault diagnosis process provided in an embodiment of this application. Based on the current battery pack charge state and the pre-selected battery insulation fault location, the measuring voltage of the insulation detection tool is adjusted. The positive output terminal of the insulation detection tool is connected to the pre-selected battery insulation fault location, and the negative output terminal is connected to the power base. The readings (i.e., output values) on the insulation detection tool are read and recorded. The readings include two parts: the displayed resistance value and the DC voltage value. The measured DC voltage and the pre-selected measured fault insulation value can be directly obtained through the insulation detection tool; that is, the measured DC voltage and the pre-selected measured fault insulation value are the direct output values ​​of the insulation detection tool. The measured DC voltage and the pre-selected measured fault insulation value are denoted as U0 and R0, respectively.

[0100] S104: When the negative terminal of the insulation testing tool is connected to the vehicle body grounding terminal and the positive terminal of the insulation testing tool is connected to the battery measurement position, the calculated DC voltage and measured resistance value between the pre-selected battery insulation fault position and the vehicle body grounding terminal are obtained; the measured resistance value is the displayed resistance value of the insulation testing tool.

[0101] Connect the negative terminal of the insulation testing tool to the vehicle's grounding terminal, and the positive terminal to the battery measurement location. The measurement location can be any one of the following: the battery's negative terminal, the internal positive terminal of each battery cell, or the battery's positive terminal. In practice, using a pre-selected battery insulation fault as a reference, move the positive output terminal of the insulation testing tool in the direction of increasing or decreasing potential, and connect the positive output terminal of the insulation testing tool to the designated measurement location. See [example description missing] for further details. Figure 2d , Figure 2d This is a schematic diagram illustrating another battery insulation fault troubleshooting process provided in an embodiment of this application. Figure 2d In this process, based on the pre-selected battery insulation fault, the positive output terminal of the insulation testing tool is moved in the direction of decreasing potential, and the positive output terminal of the insulation testing tool is connected to the negative terminal of the battery.

[0102] When the negative terminal of the insulation testing tool is connected to the vehicle body grounding terminal and the positive terminal is connected to the battery measurement location, the calculated DC voltage and measured resistance value between the pre-selected battery insulation fault location and the vehicle body grounding terminal can be obtained. The measured resistance value is the displayed resistance value of the insulation testing tool. This measured resistance value is denoted as R1. R1 is the result of a secondary measurement by the insulation testing tool. Due to the difference in the placement of the positive probe of the insulation testing tool compared to S103, the resulting voltage difference will cause the resistance measurement result to be inconsistent with that in S103; therefore, its value is represented as R1. R1 and R0 are not equal. It should be noted that the DC voltage value displayed by the insulation testing tool at this time is still U0.

[0103] Specifically, when the negative terminal of the insulation testing tool is connected to the vehicle body grounding terminal and the positive terminal of the insulation testing tool is connected to the battery measurement location, the calculated DC voltage and measured resistance value between the pre-selected battery insulation fault location and the vehicle body grounding terminal are obtained, including:

[0104] When the negative terminal of the insulation testing tool is connected to the vehicle body grounding terminal and the positive terminal of the insulation testing tool is connected to the battery measurement position, the measured resistance value is obtained;

[0105] Obtain the pressure difference between the pre-selected battery insulation fault location and the battery measurement location;

[0106] The calculated DC voltage between the pre-selected battery insulation fault location and the vehicle grounding terminal is obtained based on the differential pressure value and the measured DC voltage.

[0107] One method is to use a multimeter to obtain the voltage difference between the pre-selected battery insulation fault location and the battery measurement location. For example... Figure 2d As shown, this pressure difference value is denoted as U1.

[0108] In practice, the calculated DC voltage between the pre-selected battery insulation fault location and the vehicle grounding terminal is obtained based on the differential pressure value and the measured DC voltage, including:

[0109] When the positive output of the insulation testing tool moves in the direction of decreasing potential, that is, when the potential of the measurement position is lower than that of the pre-selected battery insulation fault position, the calculated DC voltage is the voltage value obtained by adding the voltage difference value and the measured DC voltage, that is, U0+U1;

[0110] When the positive output of the insulation testing tool moves in the direction of increasing potential, that is, when the potential of the measurement position is higher than that of the pre-selected battery insulation fault position, the calculated DC voltage is the voltage value obtained by subtracting the voltage difference value from the measured DC voltage, i.e., U0-U1.

[0111] S105: When the measured DC voltage, calculated DC voltage, pre-selected measured fault insulation value, and measured resistance value meet the preset conditions, the pre-selected battery insulation fault location is determined as the battery insulation fault location, and the battery fault insulation value is determined as the pre-selected measured fault insulation value.

[0112] After acquiring the measured DC voltage, calculating the DC voltage, pre-selecting the measured fault insulation value, and measuring the resistance value, it is determined whether the preset conditions are met. The preset condition is that the ratio of the measured resistance value to the pre-selected measured fault insulation value is equal to the ratio of the measured DC voltage to the calculated DC voltage.

[0113] When the positive output terminal of the insulation testing tool moves in the direction of decreasing potential, i.e., when the potential at the measurement location is lower than that at the pre-selected battery insulation fault location, the preset condition is:

[0114]

[0115] When the positive output of the insulation testing tool moves in the direction of increasing potential, i.e., the measurement position has a higher potential than the pre-selected battery insulation fault location, the preset condition is:

[0116]

[0117] When the measured DC voltage, calculated DC voltage, pre-selected measured fault insulation value, and measured resistance value meet the preset conditions, it indicates that the insulation fault in the battery is a single-point insulation fault. At this time, the pre-selected battery insulation fault location is determined as the battery insulation fault location, and the battery fault insulation value is determined as the pre-selected measured fault insulation value.

[0118] It should be noted that, in actual operation, considering the influence of measurement errors, the measurement range of the insulation testing tool, the direction of movement of the insulation testing tool, the direction of movement of the measuring equipment, and the magnitude of the differential pressure should all be reasonably selected. As an example, in actual operation, it is more convenient when U0 and U1 are in a 1:1 or 2:1 ratio, that is, when R1 and R0 are 2 or 3 times each.

[0119] It should also be noted that if the measured DC voltage, calculated DC voltage, pre-selected measured fault insulation value, and measured resistance value do not meet the preset conditions, it indicates that the battery has multiple insulation faults. In this case, the high-voltage connection inside the battery pack needs to be disconnected (the connection between modules or cells needs to be disconnected), and the method provided in the embodiments of this application needs to be repeated until all insulation fault points are located.

[0120] S103 and S104 can confirm whether the battery insulation fault is a single-point fault and determine whether the pre-selected battery insulation fault location is the actual battery insulation fault location.

[0121] The battery insulation fault diagnosis method provided in this application mainly consists of two steps for locating insulation faults in the power batteries of new energy vehicles. The first step is to initially locate the insulation fault, that is, to preliminarily determine the location of the pre-selected battery insulation fault by detecting the voltage status at various points. The second step is to confirm the actual insulation fault location based on the pre-selected location and determine the actual insulation value. Insulation faults are of the highest level in the field of new energy vehicles, especially when insulation problems occur in the power battery, posing a significant safety risk. This method greatly reduces the risk of electric shock and fire during the diagnosis process and can accurately and quickly locate battery insulation faults.

[0122] See Figure 3 , Figure 3 This is a schematic diagram of a battery insulation fault diagnosis device provided in an embodiment of this application. Figure 3 As shown, the device includes:

[0123] The first acquisition unit 301 is used to acquire the measurement voltage between the measurement terminal and the vehicle ground terminal; the measurement terminal is a first terminal; the first terminal is sequentially the battery negative terminal, the positive terminals inside each battery in the direction of increasing potential, and the battery positive terminal; or, the measurement terminal is a second terminal, the second terminal is sequentially the battery positive terminal, the positive terminals inside each battery in the direction of decreasing potential, and the battery negative terminal.

[0124] The first determining unit 302 is used to determine the location of the pre-selected battery insulation fault based on the measured voltage.

[0125] The second acquisition unit 303 is used to acquire, when the negative terminal of the insulation detection tool is connected to the vehicle grounding terminal and the positive terminal of the insulation detection tool is connected to the preselected battery insulation fault location, the measured DC voltage between the preselected battery insulation fault location and the vehicle grounding terminal, and the preselected measured fault insulation value between the preselected battery insulation fault location and the vehicle grounding terminal; the fault insulation value is the insulation fault resistance value.

[0126] The third acquisition unit 304 is used to acquire the calculated DC voltage and measured resistance value between the pre-selected battery insulation fault location and the vehicle grounding terminal when the negative terminal of the insulation detection tool is connected to the vehicle grounding terminal and the positive terminal of the insulation detection tool is connected to the battery measurement location; the measured resistance value is the displayed resistance value of the insulation detection tool.

[0127] The second determining unit 305 is used to determine the pre-selected battery insulation fault location as the battery insulation fault location and determine the battery fault insulation value as the pre-selected battery insulation fault insulation value when the measured DC voltage, the calculated DC voltage, the pre-selected measured fault insulation value and the measured resistance value meet preset conditions.

[0128] Optionally, in some embodiments of this application, when the positive electrode inside the battery is the positive electrode of the battery cell;

[0129] The first determining unit 302 includes:

[0130] The first determining subunit is used to determine the pre-selected battery insulation fault location as the positive electrode location of the battery cell corresponding to the change of the measured voltage from negative to positive when the measuring terminal is the first terminal.

[0131] The second determining subunit is used to determine the pre-selected battery insulation fault location as the positive electrode position of the battery cell corresponding to the change of the measured voltage from negative to positive when the measuring terminal is the second terminal.

[0132] Optionally, in some embodiments of this application, when the positive electrode inside the battery is the positive electrode of the internal module of the battery;

[0133] The first determining unit 302 includes:

[0134] The third determining subunit is used to determine the target module when the measured voltage changes from negative to positive when the measuring terminal is the first terminal; the target module is the module corresponding to the positive terminal position of the battery module when the measured voltage changes from negative to positive.

[0135] The first acquisition subunit is used to acquire the target module cell voltage between the measurement terminal inside the target module and the vehicle body grounding terminal; the measurement terminal inside the target module is a third terminal or a fourth terminal; the third terminal is, in sequence, the negative terminal of the target module, the positive terminal of each cell inside the target module in the direction of increasing potential, and the positive terminal of the target module; the fourth terminal is, in sequence, the positive terminal of the target module, the positive terminal of each cell inside the target module in the direction of decreasing potential, and the negative terminal of the target module;

[0136] The fourth determining subunit is used to determine the location of the pre-selected battery insulation fault based on the target module cell voltage.

[0137] Optionally, in some embodiments of this application, when the positive electrode inside the battery is the positive electrode of the internal module of the battery;

[0138] The first determining unit 302 includes:

[0139] The fifth determining subunit is used to determine the target module when the measured voltage changes from positive to negative when the measuring terminal is the second terminal; the target module is the module corresponding to the positive terminal position of the battery module when the measured voltage changes from positive to negative.

[0140] The second acquisition subunit is used to acquire the target module cell voltage between the measurement terminal inside the target module and the vehicle body grounding terminal; the measurement terminal inside the target module is a third terminal or a fourth terminal; the third terminal is, in sequence, the negative terminal of the target module, the positive terminal of each cell inside the target module in the direction of increasing potential, and the positive terminal of the target module; the fourth terminal is, in sequence, the positive terminal of the target module, the positive terminal of each cell inside the target module in the direction of decreasing potential, and the negative terminal of the target module;

[0141] The sixth determining subunit is used to determine the location of the pre-selected battery insulation fault based on the target module cell voltage.

[0142] Optionally, in some embodiments of this application, the third acquisition unit 304 includes:

[0143] The third acquisition subunit is used to acquire the measured resistance value when the negative terminal of the insulation testing tool is connected to the vehicle grounding terminal and the positive terminal of the insulation testing tool is connected to the battery measurement position.

[0144] The fourth acquisition subunit is used to acquire the pressure difference between the pre-selected battery insulation fault location and the battery measurement location;

[0145] The fifth acquisition subunit is used to acquire the calculated DC voltage between the preselected battery insulation fault location and the vehicle body grounding terminal based on the differential pressure value and the measured DC voltage.

[0146] The battery insulation fault diagnosis device provided in this application provides a two-step solution for locating insulation faults in the power batteries of new energy vehicles. The first step is preliminary fault location, which involves determining the pre-selected battery insulation fault location by detecting the voltage status at various points. The second step is to confirm the actual insulation fault location based on the pre-selected location and determine the actual insulation value. Insulation faults are the most serious type of fault in the new energy vehicle field, especially power battery insulation problems, which pose significant safety risks. This device greatly reduces the risk of electric shock and fire during the diagnosis process, enabling accurate and rapid diagnosis and location of battery insulation faults.

[0147] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. Regarding the methods disclosed in the embodiments, since they correspond to the systems disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the system section description.

[0148] It should also be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0149] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method of battery insulation troubleshooting, the method comprising: The method includes: Obtain the measurement voltage between the measuring end and the vehicle grounding end; the measuring end is a first end; the first end is sequentially the battery negative terminal, the positive terminals inside each battery in the direction of increasing potential, and the battery positive terminal; or, the measuring end is a second end, the second end is sequentially the battery positive terminal, the positive terminals inside each battery in the direction of decreasing potential, and the battery negative terminal; Based on the measured voltage, the location of the pre-selected battery insulation fault is determined; When the negative terminal of the insulation testing tool is connected to the vehicle body grounding terminal and the positive terminal of the insulation testing tool is connected to the pre-selected battery insulation fault location, the measured DC voltage between the pre-selected battery insulation fault location and the vehicle body grounding terminal is obtained, as well as the pre-selected measured fault insulation value between the pre-selected battery insulation fault location and the vehicle body grounding terminal; the fault insulation value is the insulation fault resistance value. When the negative terminal of the insulation testing tool is connected to the vehicle grounding terminal and the positive terminal of the insulation testing tool is connected to the battery measurement position, the calculated DC voltage and measured resistance value between the pre-selected battery insulation fault position and the vehicle grounding terminal are obtained; the measured resistance value is the displayed resistance value of the insulation testing tool, and the measurement position is any one of the battery negative terminal, the internal positive terminal of each battery, and the battery positive terminal; When the measured DC voltage, the calculated DC voltage, the pre-selected measured fault insulation value, and the measured resistance value meet preset conditions, the pre-selected battery insulation fault location is determined as the battery insulation fault location, the battery fault insulation value is determined as the pre-selected measured fault insulation value, and the ratio of the measured resistance value to the pre-selected measured fault insulation value is equal to the ratio of the measured DC voltage to the calculated DC voltage.

2. The method of claim 1, wherein, When the positive electrode inside the battery is the positive electrode of the battery cell; The step of determining the pre-selected battery insulation fault location based on the measured voltage includes: When the measuring end is the first end, when the measuring voltage changes from negative to positive, the pre-selected battery insulation fault location is determined to be the positive terminal position of the battery cell corresponding to when the measuring voltage changes from negative to positive; When the measuring terminal is the second terminal, when the measuring voltage changes from positive to negative, the pre-selected battery insulation fault location is determined to be the positive terminal position of the battery cell corresponding to when the measuring voltage changes from negative to positive.

3. The method of claim 1, wherein, When the positive electrode inside the battery is the positive electrode of the battery module; The step of determining the pre-selected battery insulation fault location based on the measured voltage includes: When the measuring end is the first end, the target module is determined when the measuring voltage changes from negative to positive; the target module is the module corresponding to the positive terminal position of the battery module when the measuring voltage changes from negative to positive. Obtain the target module cell voltage between the measurement terminal inside the target module and the vehicle body grounding terminal; the measurement terminal inside the target module is a third terminal or a fourth terminal; the third terminal is, in sequence, the negative terminal of the target module, the positive terminal of each cell inside the target module in the direction of increasing potential, and the positive terminal of the target module; the fourth terminal is, in sequence, the positive terminal of the target module, the positive terminal of each cell inside the target module in the direction of decreasing potential, and the negative terminal of the target module; Based on the target module cell voltage, the location of the pre-selected battery insulation fault is determined.

4. The method of claim 3, wherein, When the positive electrode inside the battery is the positive electrode of the battery module; The step of determining the pre-selected battery insulation fault location based on the measured voltage includes: When the measuring terminal is the second terminal, the target module is determined when the measuring voltage changes from positive to negative; the target module is the module corresponding to the positive terminal position of the battery module when the measuring voltage changes from positive to negative. Obtain the target module cell voltage between the measurement terminal inside the target module and the vehicle body grounding terminal; the measurement terminal inside the target module is a third terminal or a fourth terminal; the third terminal is, in sequence, the negative terminal of the target module, the positive terminal of each cell inside the target module in the direction of increasing potential, and the positive terminal of the target module; the fourth terminal is, in sequence, the positive terminal of the target module, the positive terminal of each cell inside the target module in the direction of decreasing potential, and the negative terminal of the target module; Based on the target module cell voltage, the location of the pre-selected battery insulation fault is determined.

5. The method according to claim 1, characterized in that, When the negative terminal of the insulation testing tool is connected to the vehicle body grounding terminal and the positive terminal of the insulation testing tool is connected to the battery measurement location, the calculated DC voltage and measured resistance value between the pre-selected battery insulation fault location and the vehicle body grounding terminal are obtained, including: When the negative terminal of the insulation testing tool is connected to the grounding terminal of the vehicle body and the positive terminal of the insulation testing tool is connected to the battery measurement position, the measured resistance value is obtained; Obtain the pressure difference between the pre-selected battery insulation fault location and the battery measurement location; Based on the differential pressure value and the measured DC voltage, the calculated DC voltage between the pre-selected battery insulation fault location and the vehicle body grounding terminal is obtained.

6. A battery insulation fault diagnosis device, characterized in that, The device includes: The first acquisition unit is used to acquire the measurement voltage between the measurement terminal and the vehicle ground terminal; the measurement terminal is a first terminal; the first terminal is sequentially the battery negative terminal, the positive terminals inside each battery in the direction of increasing potential, and the battery positive terminal; or, the measurement terminal is a second terminal, the second terminal is sequentially the battery positive terminal, the positive terminals inside each battery in the direction of decreasing potential, and the battery negative terminal. The first determining unit is used to determine the location of the pre-selected battery insulation fault based on the measured voltage. The second acquisition unit is used to acquire, when the negative terminal of the insulation testing tool is connected to the vehicle grounding terminal and the positive terminal of the insulation testing tool is connected to the preselected battery insulation fault location, the measured DC voltage between the preselected battery insulation fault location and the vehicle grounding terminal, and the preselected measured fault insulation value between the preselected battery insulation fault location and the vehicle grounding terminal; the fault insulation value is the insulation fault resistance value. The third acquisition unit is used to acquire the calculated DC voltage and measured resistance value between the pre-selected battery insulation fault location and the vehicle grounding terminal when the negative terminal of the insulation detection tool is connected to the vehicle grounding terminal and the positive terminal of the insulation detection tool is connected to the battery measurement location; the measured resistance value is the displayed resistance value of the insulation detection tool, and the measurement location is any one of the battery negative terminal, the internal positive terminal of each battery, and the battery positive terminal. The second determining unit is used to determine the pre-selected battery insulation fault location as the battery insulation fault location and to determine the battery fault insulation value as the pre-selected battery insulation fault insulation value when the measured DC voltage, the calculated DC voltage, the pre-selected measured fault insulation value and the measured resistance value meet preset conditions. The ratio of the measured resistance value to the pre-selected measured fault insulation value is equal to the ratio of the measured DC voltage to the calculated DC voltage.

7. The apparatus according to claim 6, characterized in that, When the positive electrode inside the battery is the positive electrode of the battery cell; The first determining unit includes: The first determining subunit is used to determine the pre-selected battery insulation fault location as the positive electrode location of the battery cell corresponding to the change of the measured voltage from negative to positive when the measuring terminal is the first terminal. The second determining subunit is used to determine the pre-selected battery insulation fault location as the positive electrode position of the battery cell corresponding to the change of the measured voltage from negative to positive when the measuring terminal is the second terminal.

8. The apparatus according to claim 6, characterized in that, When the positive electrode inside the battery is the positive electrode of the battery module; The first determining unit includes: The third determining subunit is used to determine the target module when the measured voltage changes from negative to positive when the measuring terminal is the first terminal; the target module is the module corresponding to the positive terminal position of the battery module when the measured voltage changes from negative to positive. The first acquisition subunit is used to acquire the target module cell voltage between the measurement terminal inside the target module and the vehicle body grounding terminal; the measurement terminal inside the target module is a third terminal or a fourth terminal; the third terminal is, in sequence, the negative terminal of the target module, the positive terminal of each cell inside the target module in the direction of increasing potential, and the positive terminal of the target module; the fourth terminal is, in sequence, the positive terminal of the target module, the positive terminal of each cell inside the target module in the direction of decreasing potential, and the negative terminal of the target module; The fourth determining subunit is used to determine the location of the pre-selected battery insulation fault based on the target module cell voltage.

9. The apparatus according to claim 8, characterized in that, When the positive electrode inside the battery is the positive electrode of the battery module; The first determining unit includes: The fifth determining subunit is used to determine the target module when the measured voltage changes from positive to negative when the measuring terminal is the second terminal; the target module is the module corresponding to the positive terminal position of the battery module when the measured voltage changes from positive to negative. The second acquisition subunit is used to acquire the target module cell voltage between the measurement terminal inside the target module and the vehicle body grounding terminal; the measurement terminal inside the target module is a third terminal or a fourth terminal; the third terminal is, in sequence, the negative terminal of the target module, the positive terminal of each cell inside the target module in the direction of increasing potential, and the positive terminal of the target module; the fourth terminal is, in sequence, the positive terminal of the target module, the positive terminal of each cell inside the target module in the direction of decreasing potential, and the negative terminal of the target module; The sixth determining subunit is used to determine the location of the pre-selected battery insulation fault based on the target module cell voltage.

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