A sampling frequency adaptive insulation detection method and battery management system

Abstract

The present invention discloses an insulation detection method and a battery management system with adaptive sampling frequency, comprising: in an unbalanced bridge circuit, respectively obtaining the total voltage of a battery pack when both the upper bridge arm and the lower bridge arm are disconnected, the first battery voltage when the upper bridge arm is closed and the lower bridge arm is disconnected, and the second battery voltage when the upper bridge arm is closed and the lower bridge arm is closed; performing a fluctuation analysis on the first battery voltage and the second battery voltage, and obtaining the first battery voltage and the second battery voltage with qualified fluctuation by adjusting the sampling frequency; obtaining the insulation resistance according to the total voltage of the battery pack, the first battery voltage and the second battery voltage with qualified fluctuation, and comparing the insulation resistance with a preset threshold value of insulation damage to obtain the insulation detection result. An adaptive voltage sampling frequency algorithm is introduced, and the sampling frequency of the voltage is adaptively adjusted according to the data fluctuation of the voltage to obtain a battery voltage with qualified fluctuation, so as to solve the problem that the distributed capacitance affects the accuracy of the insulation detection of the unbalanced bridge method.

Description

Technical Field

[0001] The present invention relates to the technical field of battery energy storage and electric vehicle insulation detection, and in particular to an insulation detection method with adaptive sampling frequency and a battery management system. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] At present, with the continuous improvement of the voltage level of battery energy storage systems and electric vehicles, the voltage level of battery energy storage systems is as high as 1500V or more, and the voltage level of electric vehicles is as high as 900V or more. For safety reasons, high-voltage battery systems require that the total positive and negative of the battery be electrically insulated from the shell. When the insulation is damaged, personal electric shock accidents may occur, which may cause personal injury or death in severe cases, and cause the battery pack to short-circuit, catch fire or even explode, threatening the personal safety of energy storage system operators and electric vehicle passengers. Therefore, real-time monitoring of the insulation status of the battery pack, timely issuing early warning information and performing relevant protection processing based on the monitoring results are of great significance to the safe and stable operation of electric vehicles and battery energy storage systems.

[0004] At present, the main insulation detection methods include balanced bridge method, unbalanced bridge method, low-frequency AC signal injection method and active insulation resistance detection method. Among them, the unbalanced bridge method is widely used due to its simple structure and high accuracy.

[0005] When the unbalanced bridge method is used in practice, its detection accuracy will be affected by many factors. Among them, there are distributed capacitances in the vehicle body. During the detection process, when the voltage state switches, the determined voltage sampling point exists in the transition process of capacitor charging and discharging. This phenomenon will greatly affect the detection accuracy of the unbalanced bridge method.

[0006] Patent CN112924829B discloses an insulation detection device, which is equipped with two resistors and measures three voltage values ​​to obtain the insulation status of the positive busbar relative to the housing and the negative busbar relative to the housing. However, this solution can only determine whether the positive and negative busbars are directly connected to the housing, and cannot calculate the accurate insulation resistance value.

[0007] Patent CN112684361B discloses a battery insulation resistance detection method, device and system, which obtains the voltage change at the voltage test point by changing the resistance value of the variable resistor in the insulation detection device, and calculates the insulation resistance of the positive bus and the negative bus relative to the shell. However, the waiting time after changing the resistance value of the variable resistor is a fixed value, so in a system with a large Y capacitor, the accuracy of the detection result is very low; in a system with a small Y capacitor, since its switching speed cannot be improved, the detection accuracy is greatly affected by the total voltage fluctuation, and the detection accuracy is relatively low. Summary of the invention

[0008] In order to solve the above problems, the present invention proposes an insulation detection method and battery management system with adaptive sampling frequency, introduces a voltage sampling frequency adaptive algorithm, and the voltage sampling frequency is adaptively adjusted according to the voltage data volatility to obtain a battery voltage with qualified volatility, thereby solving the problem that distributed capacitance affects the insulation detection accuracy of the unbalanced bridge method.

[0009] In order to achieve the above object, the present invention adopts the following technical solution:

[0010] In a first aspect, the present invention provides an insulation detection method with adaptive sampling frequency, comprising:

[0011] In an unbalanced bridge circuit, respectively obtaining a total voltage of the battery pack when both the upper bridge arm and the lower bridge arm are disconnected, a first voltage of the battery when the upper bridge arm is closed and the lower bridge arm is disconnected, and a second voltage of the battery when the upper bridge arm is disconnected and the lower bridge arm is closed;

[0012] Performing fluctuation analysis on the first battery voltage and the second battery voltage, and obtaining the first battery voltage and the second battery voltage with qualified fluctuation by adjusting the sampling frequency;

[0013] The insulation resistance is obtained according to the total voltage of the battery pack, the first voltage of the battery with qualified fluctuation, and the second voltage of the battery, and the insulation resistance is compared with a preset threshold value of insulation damage to obtain an insulation detection result.

[0014] As an optional implementation, the volatility analysis includes: calculating the variance of the last two voltage data sampled in each group of battery first voltage and battery second voltage, and judging the value volatility according to the comparison result between the variance and the frequency adjustment threshold.

[0015] As an optional implementation, the first variance and the second variance of the last two voltage data sampled in each group of battery first voltage and battery second voltage are calculated, and the first frequency adjustment threshold and the second frequency adjustment threshold are preset. If the first variance is less than the first frequency adjustment threshold or the second variance is less than the second frequency adjustment threshold, the numerical volatility is qualified, otherwise the numerical volatility is unqualified.

[0016] As an optional implementation, the frequency adjustment threshold is: the maximum allowable variance of the first battery voltage and the second battery voltage is obtained according to the specified fluctuation range of the insulation resistance and the maximum allowable fluctuation range of the first battery voltage and the second battery voltage, and the maximum allowable variance is used as the frequency adjustment threshold.

[0017] As an optional implementation, the maximum allowable fluctuation range is: according to the specified fluctuation range of the insulation resistance, the maximum allowable fluctuation range of the first battery voltage and the second battery voltage is obtained, and the maximum allowable fluctuation range is±n %, battery first voltage U p and the second battery voltage U n The corresponding maximum allowable fluctuation range is [(1- n %) U p ~(1+ n %) U p ] and [(1- n %) U n ~(1+ n %) U n ].

[0018] As an optional implementation method, a first insulation resistance between the positive bus and the vehicle body and a second insulation resistance between the negative bus and the vehicle body are obtained based on the total voltage of the battery pack, a first battery voltage with qualified fluctuation, and a second battery voltage; the smaller value of the first insulation resistance and the second insulation resistance is selected, and the smaller value is compared with a preset threshold value for insulation damage to obtain an insulation detection result.

[0019] As an optional implementation, if the first insulation resistance is less than the second insulation resistance, and the first insulation resistance is less than a preset insulation damage threshold, then the insulation is damaged;

[0020] If the first insulation resistance is less than the second insulation resistance, and the first insulation resistance is greater than the preset insulation damage threshold, the insulation is good;

[0021] If the second insulation resistance is less than the first insulation resistance, and the second insulation resistance is less than a preset insulation damage threshold, the insulation is damaged;

[0022] If the second insulation resistance is less than the first insulation resistance and the second insulation resistance is greater than a preset insulation damage threshold, the insulation is good.

[0023] In a second aspect, the present invention provides an insulation detection system with adaptive sampling frequency, comprising:

[0024] A voltage acquisition module is configured to respectively acquire, in an unbalanced bridge circuit, a total voltage of a battery pack when both an upper bridge arm and a lower bridge arm are disconnected, a first voltage of a battery when the upper bridge arm is closed and the lower bridge arm is disconnected, and a second voltage of a battery when the upper bridge arm is disconnected and the lower bridge arm is closed;

[0025] A fluctuation analysis module is configured to perform fluctuation analysis on the first battery voltage and the second battery voltage, and obtain the first battery voltage and the second battery voltage with qualified fluctuation by adjusting the sampling frequency;

[0026] The insulation detection module is configured to obtain the insulation resistance according to the total voltage of the battery pack, the first voltage of the battery with qualified fluctuation and the second voltage of the battery, and compare the insulation resistance with the preset threshold of insulation damage to obtain the insulation detection result.

[0027] In a third aspect, the present invention provides an electronic device comprising a memory and a processor, and computer instructions stored in the memory and executed on the processor, wherein when the computer instructions are executed by the processor, the method described in the first aspect is completed.

[0028] In a fourth aspect, the present invention provides a computer-readable storage medium for storing computer instructions, wherein when the computer instructions are executed by a processor, the method described in the first aspect is performed.

[0029] In a fifth aspect, the present invention provides a battery management system, including the insulation detection system with adaptive sampling frequency as described in the second aspect.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The present invention introduces a voltage sampling frequency adaptive algorithm based on the traditional unbalanced bridge method, so that the voltage sampling frequency is adaptively adjusted according to the numerical volatility of the collected voltage data, avoiding the capacitor charging and discharging process caused by the distributed capacitance of the vehicle body. Compared with the traditional unbalanced bridge method, the insulation detection accuracy of the present invention is not affected by the distributed capacitance, and the insulation resistance value can be accurately calculated, thereby realizing real-time monitoring of the insulation status between the positive and negative busbars of the vehicle power battery pack and the vehicle body, and solving the problem of low detection result accuracy in a system with large Y capacitance.

[0032] Advantages of additional aspects of the present invention will be given in part in the following description, and in part will become obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0034] Figure 1 A flow chart of an insulation detection method with adaptive sampling frequency provided in Embodiment 1 of the present invention;

[0035] Figure 2 An unbalanced bridge circuit diagram provided by Embodiment 1 of the present invention;

[0036] Figure 3 A flow chart of numerical volatility analysis provided in Example 1 of the present invention;

[0037] Figure 4This is a flow chart of determining a frequency adjustment threshold value provided in Embodiment 1 of the present invention. DETAILED DESCRIPTION

[0038] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0039] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0040] It should be noted that the terms used herein are only for describing specific embodiments, and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that the terms "include" and "have" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0041] In the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.

[0042] Example 1

[0043] like Figure 1 As shown, this embodiment provides an insulation detection method with adaptive sampling frequency, including:

[0044] S1: in an unbalanced bridge circuit, respectively obtaining a total voltage of the battery pack when both the upper bridge arm and the lower bridge arm are disconnected, a first voltage of the battery when the upper bridge arm is closed and the lower bridge arm is disconnected, and a second voltage of the battery when the upper bridge arm is disconnected and the lower bridge arm is closed;

[0045] S2: performing fluctuation analysis on the first battery voltage and the second battery voltage, and obtaining the first battery voltage and the second battery voltage with qualified fluctuation by adjusting the sampling frequency;

[0046] S3: Obtain insulation resistance according to the total voltage of the battery pack, the first voltage of the battery with qualified fluctuation, and the second voltage of the battery, and compare the insulation resistance with a preset threshold value of insulation damage to obtain an insulation detection result.

[0047] like Figure 2 As shown, this embodiment pre-builds an unbalanced bridge circuit, wherein: S 1 and S 2They are the upper bridge arm switching switch and the lower bridge arm switching switch, R p and R n They are the insulation resistance between the positive busbar and the car body and between the negative busbar and the car body respectively.

[0048] The step S1 specifically includes:

[0049] S1-1: Switch the upper arm of the unbalanced bridge S 1 and lower bridge arm switch S 2 All disconnected;

[0050] S1-2: Collect the total voltage of the battery pack U 0 ;

[0051] S1-3: Close the upper bridge arm switch S 1 , and disconnect the lower bridge arm switch at the same time S 2 ;

[0052] S1-4: At voltage sampling point 1, continuously collect the first voltages of three batteries at equal time intervals U p ;

[0053] S1-5: Disconnect the upper bridge arm switch S 1 , and close the lower bridge arm switch at the same time S 2 ;

[0054] S1-6: At voltage sampling point 1, continuously collect the second voltages of three batteries at equal time intervals U n .

[0055] The step S2 specifically includes: U p and U n Perform numerical fluctuation analysis. If the numerical fluctuation is qualified, calculate the insulation resistance; if the numerical fluctuation is unqualified, discard the current sampling. U 0 , U p , U n , and after adaptively adjusting the sampling frequency, continue sampling U 0 , U p , Un , until U p and U n The volatility is qualified.

[0056] Preferably, if Figure 3 As shown, the numerical volatility analysis includes:

[0057] S2-1: Calculate each group U p and U n The variance of the last two voltage data sampled in A p and A n ;

[0058] S2-2: Calculate frequency adjustment threshold S 1 and S 2 ;

[0059] S2-3: If A p Less than S 1 or A n Less than S 2 , the numerical volatility is qualified, otherwise the numerical volatility is unqualified.

[0060] In this embodiment, by U p , U n The variance of the last two voltage data sampled in A p , A n Compare it with the corresponding maximum allowable variance and complete it according to the comparison result U p and U n The numerical volatility analysis of , the maximum allowable variance is the frequency adjustment threshold;

[0061] In step S2-1, the variance A p and A n The calculation process is: suppose each group U p , U n The last two voltage data sampled are U 1 ,U 2 , then its variance is as shown in formula (1).

[0062] (1)

[0063] In step S2-2, the insulation resistance is analyzed by a sensitivity analysis method according to the actual operation of the electric vehicle. R p and R n The requirements of volatility set the frequency adjustment threshold; e.g. Figure 4 As shown, by determining the insulation resistance fluctuation range 、U p and U n Allowable fluctuation range, U p and U n The maximum allowable variance is U p and U n The maximum allowed variance is used as the threshold for frequency adjustment.

[0064] The specific steps are as follows:

[0065] Assume that the insulation resistance of the electric vehicle is R p , R n The volatility requirement is a %, U p , U n As the independent variable, the sensitivity expression is as shown in formula (2).

[0066] (2)

[0067] Where T is the network function. The network function T is the unbalanced bridge method. R p , R n The calculation formula is as shown in formula (3).

[0068] , (3)

[0069] According to the above formula, we can deduce

[0070] (4)

[0071] Further deduction leads to formula (5).

[0072] (5)

[0073] Simplifying the above formula, we can get the insulation resistance R p Parameters U p The sensitivity function of is shown in formula (6).

[0074] (6)

[0075] Similarly, insulation resistance R p Parameters U n The sensitivity function of is shown in formula (7).

[0076] (7)

[0077] Insulation resistance R n Parameters U p The sensitivity function of is shown in formula (8).

[0078] (8)

[0079] Insulation resistance R n Parameters U n The sensitivity function of is shown in formula (9).

[0080] (9)

[0081] According to the relative offset formula, the corresponding relationship between the relative offset of the insulation resistance and the relative offset of the voltage acquisition is obtained. The relative offset formula is shown in formula (10).

[0082] (10)

[0083] At this time, according to the insulation resistance R p , R n Volatility Requirements a %,get U p and U n The maximum permissible fluctuation range b %, in order to more intuitively represent the fluctuation of the data, after obtaining the maximum allowable fluctuation range of the voltage sampling value, the corresponding maximum allowable variance of the voltage sampling value is obtained;

[0084] That is, the maximum allowable fluctuation range is ±n %, U p and U n The reference value is U p0 and U n0 ,correspond U p and U n The maximum allowable fluctuation range is [(1- n %) U p ~(1+ n %) U p ] and [(1- n %) U n ~(1+ n %) U n ],according to U p 、(1- n %) U p 、(1+ n %) U p as well as U n 、(1- n %) U n 、(1+ n %) U n The obtained variance is U p and U n The maximum allowed variance S 1 and S 2 ;like A p Less than S 1 or A n Less than S 2 , then the data volatility is qualified, if A p Greater than S 1 or A n Greater than S 2 The data volatility is unqualified.

[0085] In this embodiment, if the value volatility meets the requirement, it means that at least the second and third voltage sampling values ​​are not in the transition process of capacitor charging and discharging, that is, the data collected for the second and third time are available and can be used as the basis for insulation resistance calculation;

[0086] If the value fluctuation does not meet the requirements, it means that at least the voltage sampling points of the first two voltage collections are in the transition process of capacitor charging and discharging. At this time, all voltage data collected by this round of insulation detection should be discarded, and the voltage sampling frequency should be adjusted;

[0087] The charging and discharging process of the distributed capacitance can be avoided by reducing the sampling frequency or increasing the sampling interval. The sampling interval can be increased by 10ms each round. According to the requirements of the actual working conditions, the maximum sampling interval is generally not more than 200ms. After reducing the sampling frequency, the next round of voltage sampling is carried out.

[0088] In step S3, according to the collected U 0 , U p , U n Get the insulation resistance between the positive and negative busbars and the vehicle body R p , R n ;Select insulation resistance R p , R n The smaller value of R p , R n The smaller value is used as the preset threshold value for insulation damage R 0 Make comparisons;

[0089] If exists R p < R n ,and R p < R 0 , indicating insulation damage, the driver needs to be reminded to perform maintenance;

[0090] If exists R p < R n ,and R p > R 0 , indicating that the insulation is good and no maintenance is required;

[0091] If exists R n < R p ,and R n < R 0 , indicating insulation damage, the driver needs to be reminded to perform maintenance;

[0092] If exists R n < R p ,and R n > R 0 , indicating that the insulation is good and no maintenance is required.

[0093] Example 2

[0094] This embodiment provides an insulation detection system with adaptive sampling frequency, including:

[0095] A voltage acquisition module is configured to respectively acquire, in an unbalanced bridge circuit, a total voltage of a battery pack when both an upper bridge arm and a lower bridge arm are disconnected, a first voltage of a battery when the upper bridge arm is closed and the lower bridge arm is disconnected, and a second voltage of a battery when the upper bridge arm is disconnected and the lower bridge arm is closed;

[0096] A fluctuation analysis module is configured to perform fluctuation analysis on the first battery voltage and the second battery voltage, and obtain the first battery voltage and the second battery voltage with qualified fluctuation by adjusting the sampling frequency;

[0097] The insulation detection module is configured to obtain the insulation resistance according to the total voltage of the battery pack, the first voltage of the battery with qualified fluctuation and the second voltage of the battery, and compare the insulation resistance with the preset threshold of insulation damage to obtain the insulation detection result.

[0098] It should be noted that the above modules correspond to the steps described in Example 1, and the examples and application scenarios implemented by the above modules and the corresponding steps are the same, but are not limited to the contents disclosed in the above Example 1. It should be noted that the above modules, as part of the system, can be executed in a computer system such as a set of computer executable instructions.

[0099] In further embodiments, there is also provided:

[0100] A battery management system includes the insulation detection system with adaptive sampling frequency as described in Example 2.

[0101] An electronic device includes a memory and a processor, and computer instructions stored in the memory and executed on the processor, wherein when the computer instructions are executed by the processor, the method described in Embodiment 1 is performed. For the sake of brevity, it will not be described in detail here.

[0102] It should be understood that in this embodiment, the processor may be a central processing unit CPU, and the processor may also be other general-purpose processors, digital signal processors DSP, application-specific integrated circuits ASIC, off-the-shelf programmable gate arrays FPGA or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0103] The memory may include a read-only memory and a random access memory, and provide instructions and data to the processor. A portion of the memory may also include a non-volatile random access memory. For example, the memory may also store information about the device type.

[0104] A computer-readable storage medium is used to store computer instructions, and when the computer instructions are executed by a processor, the method described in Example 1 is completed.

[0105] The method in Example 1 can be directly embodied as a hardware processor, or a combination of hardware and software modules in the processor. The software module can be located in a mature storage medium in the field such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory, or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory, and the processor reads the information in the memory and completes the steps of the above method in combination with its hardware. To avoid repetition, it is not described in detail here.

[0106] Those skilled in the art will appreciate that the units, i.e., algorithm steps, of the various examples described in conjunction with this embodiment can be implemented in electronic hardware or in a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0107] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0108] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the scope of protection of the present invention.

Claims

1. A sampling frequency adaptive insulation detection method, characterized in that: include: In an unbalanced bridge circuit, respectively obtaining a total voltage of the battery pack when both the upper bridge arm and the lower bridge arm are disconnected, a first voltage of the battery when the upper bridge arm is closed and the lower bridge arm is disconnected, and a second voltage of the battery when the upper bridge arm is disconnected and the lower bridge arm is closed; Performing fluctuation analysis on the first battery voltage and the second battery voltage, and obtaining the first battery voltage and the second battery voltage with qualified fluctuation by adjusting the sampling frequency; Obtain insulation resistance according to the total voltage of the battery pack, the first voltage of the battery with qualified fluctuation, and the second voltage of the battery, and compare the insulation resistance with a preset threshold value of insulation damage to obtain an insulation detection result; The volatility analysis includes: calculating the variance of the last two voltage data sampled in each group of battery first voltage and battery second voltage, and judging the value volatility according to the comparison result of the variance and the frequency adjustment threshold; Calculate the first variance and the second variance of the last two voltage data sampled from the first voltage and the second voltage of each group of batteries, preset the first frequency adjustment threshold and the second frequency adjustment threshold, if the first variance is less than the first frequency adjustment threshold or the second variance is less than the second frequency adjustment threshold, the numerical volatility is qualified, otherwise the numerical volatility is unqualified; The frequency adjustment threshold is: the maximum allowable variance of the first battery voltage and the second battery voltage is obtained according to the specified fluctuation range of the insulation resistance and the maximum allowable fluctuation range of the first battery voltage and the second battery voltage, and the maximum allowable variance is used as the frequency adjustment threshold.

2. The insulation detection method with adaptive sampling frequency according to claim 1, characterized in that: The maximum allowable fluctuation range is: the maximum allowable fluctuation range of the first battery voltage and the second battery voltage is obtained according to the specified fluctuation range of the insulation resistance, and the maximum allowable fluctuation range is set to ±n %, battery first voltage U p and the second battery voltage U n The corresponding maximum allowable fluctuation range is [(1- n %) U p ~(1+ n %) U p ] and [(1- n %) U n ~(1+ n %) U n ].

3. The insulation detection method with adaptive sampling frequency according to claim 1, characterized in that: The first insulation resistance between the positive bus and the vehicle body and the second insulation resistance between the negative bus and the vehicle body are obtained according to the total voltage of the battery pack, the first voltage of the battery with qualified fluctuation, and the second voltage of the battery; the smaller value of the first insulation resistance and the second insulation resistance is selected, and the smaller value is compared with the preset threshold value of insulation damage to obtain the insulation detection result.

4. The insulation detection method with adaptive sampling frequency as claimed in claim 3, characterized in that: If the first insulation resistance is less than the second insulation resistance, and the first insulation resistance is less than a preset insulation damage threshold, the insulation is damaged; If the first insulation resistance is less than the second insulation resistance, and the first insulation resistance is greater than the preset insulation damage threshold, the insulation is good; If the second insulation resistance is less than the first insulation resistance, and the second insulation resistance is less than a preset insulation damage threshold, the insulation is damaged; If the second insulation resistance is less than the first insulation resistance and the second insulation resistance is greater than a preset insulation damage threshold, the insulation is good.

5. An insulation detection system with adaptive sampling frequency, characterized in that: include: A voltage acquisition module is configured to respectively acquire, in an unbalanced bridge circuit, a total voltage of a battery pack when both an upper bridge arm and a lower bridge arm are disconnected, a first voltage of a battery when the upper bridge arm is closed and the lower bridge arm is disconnected, and a second voltage of a battery when the upper bridge arm is disconnected and the lower bridge arm is closed; A fluctuation analysis module is configured to perform fluctuation analysis on the first battery voltage and the second battery voltage, and obtain the first battery voltage and the second battery voltage with qualified fluctuation by adjusting the sampling frequency; The insulation detection module is configured to obtain the insulation resistance according to the total voltage of the battery pack, the first voltage of the battery with qualified fluctuation, and the second voltage of the battery, and compare the insulation resistance with a preset threshold value of insulation damage to obtain an insulation detection result; The volatility analysis includes: calculating the variance of the last two voltage data sampled in each group of battery first voltage and battery second voltage, and judging the value volatility according to the comparison result of the variance and the frequency adjustment threshold; Calculate the first variance and the second variance of the last two voltage data sampled from the first voltage and the second voltage of each group of batteries, preset the first frequency adjustment threshold and the second frequency adjustment threshold, if the first variance is less than the first frequency adjustment threshold or the second variance is less than the second frequency adjustment threshold, the numerical volatility is qualified, otherwise the numerical volatility is unqualified; The frequency adjustment threshold is: the maximum allowable variance of the first battery voltage and the second battery voltage is obtained according to the specified fluctuation range of the insulation resistance and the maximum allowable fluctuation range of the first battery voltage and the second battery voltage, and the maximum allowable variance is used as the frequency adjustment threshold.

6. A battery management system, characterized in that: The invention comprises the insulation detection system with adaptive sampling frequency as described in claim 5.

7. An electronic device, characterized in that: The method comprises a memory and a processor and computer instructions stored in the memory and executed on the processor, wherein when the computer instructions are executed by the processor, the method according to any one of claims 1 to 4 is completed.

8. A computer-readable storage medium, characterized in that: Used to store computer instructions, which, when executed by a processor, complete the method described in any one of claims 1 to 4.

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