Method, system, vehicle and storage medium for diagnosing power battery insulation fault

Abstract

The present invention discloses a method, system, vehicle and storage medium for diagnosing power battery insulation fault, including: step 1. obtaining vehicle terminal time and insulation resistance at each moment; step 2. dividing the trip and working condition according to the time series, and extracting non-charging working condition data and charging working condition data respectively; step 3. extracting charging working condition data, judging whether the charging insulation resistance is abnormal; extracting non-charging working condition data; judging whether the non-charging insulation resistance is abnormal; step 4. issuing a system alarm according to the abnormality judgment rule. The present invention can diagnose thermal runaway caused by external reasons of the battery cell.

Description

Technical Field

[0001] The present invention belongs to the technical field of fault diagnosis of power lithium batteries or lithium battery energy storage systems, and specifically relates to a method, system, vehicle and storage medium for diagnosing insulation faults of power batteries. Background Art

[0002] Lithium-ion batteries have become the preferred battery for electric vehicles due to their high energy density and long cycle life. However, the safety performance of power batteries has always been the focus of attention in the industry. The current solution to determine whether power batteries have safety risks is usually to collect the static cell voltage of the battery, and use the static cell voltage to determine whether the battery has internal short circuits, lithium deposition and other abnormalities. If the battery has internal short circuits or lithium deposition, the battery has a risk of thermal runaway. However, the cause of thermal runaway of power batteries is not only manifested in the battery cell, but may also be caused by external reasons, such as battery cell leakage, aging and breaking of wiring harnesses, etc., which will still cause thermal runaway of the battery pack, but this phenomenon cannot be effectively determined by battery voltage. If battery cell leakage, aging and breaking of wiring harnesses, etc. are not identified and warned in advance, they may cause thermal runaway of the battery, resulting in serious accidents.

[0003] Therefore, it is necessary to develop a method, system, vehicle and storage medium for diagnosing power battery insulation failure. Summary of the invention

[0004] The object of the present invention is to provide a method, system, vehicle and storage medium for diagnosing insulation faults of power batteries, which can diagnose thermal runaway caused by external reasons of the battery cell.

[0005] In a first aspect, a method for diagnosing a power battery insulation fault according to the present invention comprises the following steps:

[0006] Step 1. Obtain vehicle terminal time and insulation resistance at each moment;

[0007] Step 2. Divide the trip and working condition by time series, and extract the non-charging working condition data and the charging working condition data respectively;

[0008] Step 3. Extract charging condition data and design a sliding window to count the number of insulation resistances less than or equal to the preset resistance threshold R0 in the sliding window, and calculate the proportion M of insulation resistances less than R0 in the total number of sliding windows. If M is greater than or equal to the preset threshold M0, record charging insulation abnormality information;

[0009] Extract non-charging condition data, design a sliding window, count the number of insulation resistances less than or equal to the preset resistance threshold R0 in the sliding window, and calculate the proportion M of insulation resistances less than R0 in the total number of sliding windows. If M is greater than or equal to the preset threshold M0, number the insulation resistances in the non-charging condition data, that is, the insulation resistance R1 is numbered X1, the insulation resistance R2 is numbered X2, the insulation resistance R3 is numbered X3, and so on. n The number is X n , and calculate the mean of the numbers And according to the insulation resistance R i and X i Calculate the insulation resistance change trend W, where 1≤i≤n and i is an integer, and determine the size of W. If W≤W0, record the non-charging insulation resistance abnormal information, otherwise terminate the calculation of the trip;

[0010] Step 4. If there is charging insulation abnormality information and non-charging insulation abnormality information in the same trip, it is determined to be a power battery insulation failure, and a power battery insulation resistance failure warning is issued.

[0011] Optionally, step 4 further includes: if there is only charging insulation abnormality information but no non-charging insulation abnormality information in the same trip, it is determined to be a charging pile insulation fault, and a charging pile insulation resistance fault warning is issued. The present invention can also determine whether it is an insulation fault of the charging pile based on the charging insulation abnormality information and the absence of non-charging insulation abnormality information, and issue a corresponding fault reminder.

[0012] Optionally, step 4 further includes: if there is only non-charging insulation resistance abnormality information but no charging insulation abnormality information in the same trip, it is determined to be a non-battery insulation fault, and a warning about the insulation resistance fault of the whole vehicle other than the power battery is issued. The present invention can also determine whether it is an insulation resistance fault of the whole vehicle other than the power battery based on the charging insulation abnormality information and the absence of non-charging insulation abnormality information, and issue a corresponding fault reminder.

[0013] Optionally, step 1 also includes cleaning the data, eliminating obviously erroneous data, null values, default values, and removing abnormal data that exceeds the normal range, is repeated, and is redundant; eliminating abnormal data reduces the amount of data calculation and improves the accuracy of data calculation.

[0014] Optionally, the data is divided into several trips, from the start of charging to the start of the next charging is defined as a trip, and each trip is divided into a charging condition and a non-charging condition; the insulation resistance data of the charging condition and the insulation resistance data of the non-charging condition of a single trip are extracted respectively. The present invention classifies and processes the data according to the trip and condition so as to accurately determine the cause of the fault.

[0015] Optionally, in step 1, the vehicle side adopts the GBT32960 standard to upload data to the cloud service side. The present invention is arranged in the cloud, and the calculation data source is the data uploaded by the vehicle according to the GBT32960 requirements, and the vehicle does not need to add additional equipment or other requirements. After the cloud receives the data uploaded by the vehicle, it can execute according to the steps of this method to realize the remote diagnosis function.

[0016] Optionally, R0 is 200 kΩ; M0 is 50%; W0 is -4. The values ​​of the above data are obtained through experimental verification, which can ensure the accuracy of fault judgment.

[0017] In a second aspect, a system for diagnosing insulation faults of power batteries according to the present invention comprises a memory and a controller, wherein a computer-readable program is stored in the memory, and when the computer-readable program is called by the controller, the steps of the method for diagnosing insulation faults of power batteries according to the present invention can be executed.

[0018] In a third aspect, a storage medium according to the present invention stores a computer-readable program therein, and when the computer-readable program is called, the steps of the method for diagnosing power battery insulation fault according to the present invention can be executed.

[0019] The present invention has the following advantages:

[0020] (1) The present invention can diagnose thermal runaway of power batteries caused by external reasons of the battery cells (such as battery cell leakage, aging and damage of wiring harnesses, etc., which cannot be effectively determined by the existing battery voltage method), so it can better identify insulation faults of power lithium batteries.

[0021] (2) The present invention obtains charging insulation abnormality information and non-charging insulation abnormality information according to the insulation resistance value at each moment, and then determines the fault type in combination with the charging insulation abnormality information and the non-charging insulation abnormality information. It can diagnose power battery insulation fault, charging pile insulation fault, and vehicle (except power battery) insulation resistance fault, and issue corresponding fault warnings.

[0022] (3) The present invention is deployed in the cloud, and the calculation data source is the data uploaded by the vehicle according to the requirements of GBT32960. The vehicle does not need to add additional equipment or other requirements. After the cloud receives the data uploaded by the vehicle, it can implement the remote fault diagnosis function according to the steps of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a flow chart of this embodiment. DETAILED DESCRIPTION

[0024] The present invention will be described in detail below with reference to the accompanying drawings.

[0025] like Figure 1 As shown, in this embodiment, a method for diagnosing a power battery insulation fault includes the following steps:

[0026] Step 1. Data cleaning: Eliminate obviously erroneous data, null values, default values, and remove abnormal data such as those that are beyond the normal range, repeated, and redundant. Sort the data by the time of vehicle terminal production, eliminate abnormal data, reduce the amount of data calculation, and improve the accuracy of data calculation. Extract the vehicle terminal time and the insulation resistance at each moment in kΩ.

[0027] Step 2. Divide the trip and working condition by time series, and extract the non-charging working condition data and charging working condition data respectively, specifically:

[0028] The data is divided into several trips (a trip is defined as from the start of charging to the next start of charging), and then the data is divided into several trips for each trip, from the start of charging to the next start of charging is defined as a trip, and then each trip is divided into charging conditions and non-charging conditions; the insulation resistance data of the charging condition and the insulation resistance data of the non-charging condition of a single trip are extracted respectively.

[0029] Step 3. Extract charging condition data, design a sliding window, the sliding window length is k (in this embodiment, k = 50, the unit is frame, k is a threshold, which can be preset or adjusted as needed through big data calculation results), and the step size of the sliding window is less than or equal to k. Count the number of insulation resistances less than or equal to the preset resistance threshold R0 (R0 = 200kΩ) in the sliding window, and calculate the proportion M of insulation resistances less than R0 in the total number of sliding windows. If M is greater than or equal to M0 = 50%, record the charging insulation abnormality information; wherein, R0 = 200kΩ and M0 = 50% are obtained through experimental verification.

[0030] Extract non-charging condition data, design a sliding window, the sliding window length is k (in this embodiment, k = 50, k is a threshold value, which can be preset or adjusted as needed through big data calculation results), and the step size of the sliding window is less than or equal to k. Count the number of insulation resistances less than or equal to the preset resistance threshold R0 in the sliding window, and calculate the proportion M of insulation resistances less than R0 in the total number of sliding windows. If M is greater than or equal to the preset threshold M0, the insulation resistances in the non-charging condition data are numbered, that is, the insulation resistance R1 is numbered X1, the insulation resistance R2 is numbered X2, the insulation resistance R3 is numbered X3, and so on. The insulation resistance R n The number is X n , and calculate the mean of the numbers And according to the insulation resistance R i and X iCalculate the insulation resistance change trend W, where 1≤i≤n and i is an integer, and determine the size of W. If W≤W0, record the non-charging insulation resistance abnormal information, otherwise end the calculation of the trip.

[0031] In this embodiment, the mean of the numbers is calculated. Specifically:

[0032]

[0033] In this embodiment, R i ∈[R1,R2,R3,...,R n ], X i ∈[X1,X2,X3,...,X n ]=[1,2,3,...,n], 1≤i≤n and i is an integer, according to R i and X i Calculate the insulation resistance change trend W, specifically:

[0034]

[0035] When W≤W0 in a certain stroke, the non-charging insulation abnormality information is recorded. In this embodiment, W0 is -4, which is obtained through experimental verification.

[0036] Step 4: Rules for judging differences:

[0037] If only charging insulation abnormality information is found in the same trip, but no non-charging insulation abnormality information is found, it is determined to be a charging pile insulation failure, and the system issues a warning about the charging pile insulation resistance failure;

[0038] If there is no charging insulation abnormality information but only non-charging insulation abnormality information in the same trip, it is determined to be a non-battery insulation fault, and the system issues a warning about the insulation resistance fault of the entire vehicle (except the power battery);

[0039] If there is charging insulation abnormality information and non-charging insulation abnormality information in the same trip, it is determined to be a battery insulation failure, and the system issues a warning about the power battery insulation resistance failure.

[0040] The present invention can be deployed in the cloud, and the calculation data source is the data uploaded by the vehicle according to the requirements of GBT32960, and the vehicle does not need to add additional equipment or other requirements. After the cloud receives the data uploaded by the vehicle, it executes according to the steps of the method.

[0041] In this embodiment, a system for diagnosing insulation faults of a power battery includes a memory and a controller. The memory stores a computer-readable program. When the computer-readable program is called by the controller, it can execute the steps of the method for diagnosing insulation faults of a power battery as described in this embodiment.

[0042] In this embodiment, a storage medium stores a computer-readable program, and when the computer-readable program is called by a controller, the steps of the method for diagnosing a power battery insulation fault as described in this embodiment can be executed.

[0043] The steps of the methods or algorithms described in the embodiments disclosed in the present invention may also be implemented by hardware, software modules executed by a processor, or a combination of the two. The software modules may be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0044] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for diagnosing power battery insulation fault, characterized in that: The following steps are involved: Step 1. Obtain vehicle terminal time and insulation resistance at each moment; Step 2. Divide the trip and working condition by time series, and extract the non-charging working condition data and the charging working condition data respectively; Step 3. Extract charging condition data and design a sliding window to count the number of insulation resistances less than or equal to the preset resistance threshold R0 in the sliding window, and calculate the proportion M of insulation resistances less than R0 in the total number of sliding windows. If M is greater than or equal to the preset threshold M0, record charging insulation abnormality information; Extract non-charging condition data, design a sliding window, count the number of insulation resistances less than or equal to the preset resistance threshold R0 in the sliding window, and calculate the proportion M of insulation resistances less than R0 in the total number of sliding windows. If M is greater than or equal to the preset threshold M0, number the insulation resistances in the non-charging condition data, that is, the insulation resistance R1 is numbered X1, the insulation resistance R2 is numbered X2, the insulation resistance R3 is numbered X3, and so on. n The number is X n , and calculate the mean of the numbers And according to the insulation resistance R i and X i Calculate the insulation resistance change trend W, where 1≤i≤n and i is an integer, and determine the size of W. If W≤W0, record the non-charging insulation resistance abnormal information, otherwise terminate the calculation of the trip; Step 4. If there is charging insulation abnormality information and non-charging insulation abnormality information in the same trip, it is determined to be a power battery insulation failure, and a power battery insulation resistance failure warning is issued.

2. The method for diagnosing power battery insulation fault according to claim 1, characterized in that: The step 4 also includes: if there is only charging insulation abnormality information but no non-charging insulation abnormality information in the same trip, it is determined to be a charging pile insulation failure, and a charging pile insulation resistance failure warning is issued.

3. The method for diagnosing power battery insulation fault according to claim 2, characterized in that: The step 4 also includes: if there is only non-charging insulation resistance abnormality information but no charging insulation abnormality information in the same trip, it is determined to be a non-battery insulation fault, and an insulation resistance fault warning for the entire vehicle other than the power battery is issued.

4. The method for diagnosing power battery insulation fault according to any one of claims 1 to 3, characterized in that: The step 1 also includes cleaning the data, eliminating obviously erroneous data, null values, default values, and removing abnormal data that exceeds the normal range, is repeated, and is redundant.

5. The method for diagnosing power battery insulation fault according to claim 4, characterized in that: In step 3, according to the insulation resistance R i and X i Calculate the insulation resistance change trend W, specifically:

6. The method for diagnosing power battery insulation fault according to claim 1, 2, 3 or 5, characterized in that: In step 2, the data is divided into several trips, from the start of charging to the start of the next charging is defined as a trip, and each trip is divided into a charging condition and a non-charging condition; the insulation resistance data of the charging condition and the insulation resistance data of the non-charging condition of a single trip are extracted respectively.

7. The method for diagnosing power battery insulation fault according to claim 6, characterized in that: In step 1, the vehicle side adopts the GBT32960 standard to upload data to the cloud server side.

8. The method for diagnosing power battery insulation fault according to claim 1, 2, 3, 5 or 7, characterized in that: The R0 is 200 kΩ; the M0 is 50%; and the W0 is -4.

9. A system for diagnosing power battery insulation faults, characterized in that: It comprises a memory and a controller, wherein the memory stores a computer-readable program, and when the computer-readable program is called by the controller, it can execute the steps of the method for diagnosing power battery insulation fault as claimed in any one of claims 1 to 8.

10. A storage medium, characterized in that: A computer-readable program is stored therein, and when the computer-readable program is called, the steps of the method for diagnosing power battery insulation fault as claimed in any one of claims 1 to 8 can be executed.

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