On-line detection method and detection system for internal short circuit of vehicle-mounted power battery and medium

Abstract

The invention relates to the technical field of vehicle-mounted power battery detection, in particular to a vehicle-mounted power battery internal short circuit online detection method and system and a medium. Comprising the following steps: after the power battery completes a set mileage, when the SOC of the power battery is within a set range, collecting the voltage before and after the set standing time of each battery cell in the power battery; calculating the voltage drop of each battery cell based on the voltage before and after the set standing time of each battery cell; comparing the voltage drop with a standard voltage drop, judging whether abnormity exists or not, and if the battery cell is abnormal within a set continuous number of times, judging that the battery cell has an internal short circuit problem. The on-line detection method for the internal short circuit of the vehicle-mounted power battery is simple, whether the internal short circuit problem exists in the power battery or not can be accurately detected on line, the problems of misjudgment and missed judgment are avoided, the accuracy of judgment of the internal short circuit problem of the power battery is improved, and the use safety of the power battery is improved.

Description

Background Art

[0002] Power batteries have been widely used in electric vehicles, and the safety and reliability of power batteries are related to the safe use of electric vehicles. The application of power batteries is affected by their characteristics and has special requirements for ambient temperature and usage methods. During the application process, it is necessary not only to ensure that they operate in a good temperature environment, but also to set reasonable usage methods and detection methods. Reasonable usage methods ensure the maximum performance of the battery, and detection methods ensure that problems with the battery can be discovered in time to avoid greater battery damage or even battery safety accidents.

[0003] Internal short circuit of battery is a safety issue during the use of battery. The possible reasons for internal short circuit of battery are as follows: First, the power battery is charged under low temperature conditions. The performance of the power battery is determined by the fact that if the battery is charged at low temperature, it is easy for the battery to form crystals. Over time, the crystal growth punctures the battery diaphragm, which causes an internal short circuit in the power battery. Second, when the battery is overcharged or over-discharged, it causes irreversible ions, which will also cause internal short circuit in the battery during the long-term accumulation process.

[0004] In order to accurately determine whether the power battery cell has an internal short circuit, the prior art has proposed a method for detecting an internal short circuit of a power battery. The method is as follows: when the vehicle is running or charging again, the minimum voltage of the battery is detected to be lower than the set value and lasts for a predetermined time, then it is determined that there is a short circuit, and the battery maintenance operation is prompted through the BMS; when the battery is at the end of discharge, the difference in the static state of the battery is identified through the BMS. If the battery capacity difference is too large, exceeds the set value, and lasts for a predetermined time, it is determined that the battery has a short circuit, and an alarm is issued through the BMS to remind the maintenance operation of the battery; by recording the number of times the battery reaches the cut-off voltage in the BMS, when the difference in the number of times the battery is charged or discharged is greater than the set value, it is determined that the battery has a short circuit, and an alarm is issued through the BMS to remind the maintenance operation of the battery. This detection method uses multiple means to identify the internal short circuit of the battery. Based on long-term operation data and combined with statistical methods, it can identify the internal short circuit of the battery to the greatest extent.

[0005] However, this detection method also has some problems. This detection method determines whether there is an internal short circuit in the battery cell by judging the maximum voltage difference of the battery. But in fact, a large pressure difference may be caused by the inconsistency of the internal resistance of the battery. This detection method will frequently give false alarms. In addition, if a batch of battery cells in the battery pack have internal short circuit problems, the pressure difference may not be abnormal, and it is easy to miss the report. Summary of the invention

[0006] The purpose of this application is to address the deficiencies of the above-mentioned background technology and to provide an online detection method, detection system and medium for internal short circuit of a vehicle-mounted power battery.

[0007] The technical solution of the present application is: an online detection method for internal short circuit of a vehicle-mounted power battery, comprising:

[0008] After the power battery has completed the set mileage, when the SOC of the power battery is within the set range, the voltage of each cell in the power battery before and after the set rest time is collected;

[0009] Calculate the voltage drop of each cell based on the voltage before and after the set rest time of each cell;

[0010] The voltage drop is compared with the standard voltage drop to determine whether there is an abnormality. If the battery cell has an abnormality within a set number of consecutive times, it is determined that the battery cell has an internal short circuit problem.

[0011] According to an on-vehicle power battery internal short circuit online detection method provided in the present application, the set mileage is 100 km to 200 km.

[0012] According to an on-vehicle power battery internal short circuit online detection method provided by the present application, the setting range is 70% to 90%.

[0013] According to an on-vehicle power battery internal short circuit online detection method provided by the present application, the set standing time is 2h to 6h.

[0014] According to an online detection method for internal short circuit of a vehicle-mounted power battery provided by the present application, the method of comparing the voltage drop with the standard voltage drop to determine whether there is an abnormality includes: comparing the voltage drop of the battery cell with the standard voltage drop, and if the voltage drop exceeds the standard voltage drop, it is determined that the battery cell has an abnormality.

[0015] According to an online detection method for internal short circuit of a vehicle-mounted power battery provided by the present application, the method for determining whether the battery cell has an internal short circuit problem includes: if the battery cell is determined to be abnormal in at least two consecutive detections, then determining that the battery cell has an internal short circuit problem.

[0016] The present application also provides an on-vehicle power battery internal short circuit online detection system, the detection system is used to operate according to any of the above-mentioned on-vehicle power battery internal short circuit online detection methods, including:

[0017] A cell voltage collection module, which is used to collect the voltage of the cell before and after the power battery is at a set mileage, the power battery SOC is within a set range, and the power battery is at a set rest time;

[0018] A cell voltage drop acquisition module, wherein the cell voltage drop acquisition module acquires the voltage drop based on the voltage of the cell before and after the set standing time acquired by the cell voltage acquisition module;

[0019] A cell abnormality judgment module, which is used to compare the voltage drop of the cell with the standard voltage drop and judge whether the cell is abnormal;

[0020] The battery cell internal short circuit judgment module is used to judge whether the battery cell has an internal short circuit problem when the battery cell is abnormal for a set number of consecutive times.

[0021] According to an on-vehicle power battery internal short circuit online detection system provided by the present application, the battery cell abnormality judgment module is used to compare the voltage drop of the battery cell with the standard voltage drop, and make a judgment that the battery cell has an abnormality when the voltage drop exceeds the standard voltage drop, otherwise it is judged that the battery cell does not have an abnormality.

[0022] According to an on-vehicle power battery internal short circuit online detection system provided by the present application, the battery cell internal short circuit judgment module is used to determine that the battery cell has an internal short circuit problem when the battery cell has an abnormality at least twice in succession, otherwise it is used to determine that the battery cell does not have an internal short circuit problem.

[0023] The present application also provides a computer-readable storage medium, in which at least one program code is stored. The at least one program code is loaded and executed by a processor to implement the operations performed by the above-mentioned method for online detection of internal short circuit of a vehicle-mounted power battery.

[0024] The advantages of this application are as follows: 1. This application determines whether there is an abnormality in the battery cell by collecting the voltage drop under set conditions, and determines whether there is an internal short circuit problem by multiple consecutive abnormal situations, thereby eliminating the abnormal situation of the battery cell voltage drop caused by accidental factors, avoiding misjudgment and missed judgment, and improving the accuracy of the internal short circuit judgment of the power battery. The entire judgment method is simple and efficient;

[0025] 2. This application sets a set mileage for the power battery, that is, after each set mileage is completed, an online test is performed, so that the time of two consecutive tests can be distinguished as much as possible, so that there is a larger gap between two consecutive tests, the judgment accuracy of the internal short circuit detection is improved, and the error is eliminated;

[0026] 3. This application sets the SOC range of the power battery, because the voltage drop of the power battery cell within this set range is most obvious. Performing voltage drop collection and detection within this set range can minimize the error of data collection and improve the accuracy of judgment;

[0027] 4. This application sets a rest time for the power battery. The rest time of the power battery is directly related to the accuracy of the voltage drop data collection. If the rest time is too short, the polarization of the battery cell is not completely eliminated. If the rest time is too long, the accuracy of the statistical results of the data will be affected. By setting an appropriate rest time, the error of data collection can be eliminated and the accuracy of the judgment results can be improved.

[0028] 5. This application can determine whether the battery cell has an abnormality by comparing the voltage drop with the standard voltage drop. This judgment method is very simple and the result of judging the abnormality is very accurate. It can accurately determine whether the battery cell has an abnormality during a single detection process.

[0029] 6. The present application makes it very simple to judge whether there is an internal short circuit. It only needs at least two consecutive abnormalities to be considered that there is an internal short circuit. Multiple consecutive abnormalities eliminate accidental factors, avoid missed judgments and misjudgments, and improve the accuracy of judging the internal short circuit problem.

[0030] 7. The present application also provides an on-vehicle power battery internal short-circuit online detection system. The detection system of the present application can be integrated into the vehicle's control system to facilitate automated and intelligent online detection of the power battery, thereby improving the vehicle's intelligence level and improving the safety of power battery use.

[0031] The on-vehicle power battery internal short circuit online detection method of the present application is simple, and can accurately detect online whether the power battery has an internal short circuit problem, thereby avoiding the problem of misjudgment or missed judgment, improving the accuracy of judging the internal short circuit problem of the power battery, and improving the safety of the power battery use. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 : Schematic diagram of the online detection process of internal short circuit of the vehicle power battery of the present application. DETAILED DESCRIPTION

[0033] The embodiments of the present application are described in detail below, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0034] In the description of the present application, it should be understood that the terms "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0035] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0036] The present application is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0037] The present application relates to an online detection method for internal short circuit of a vehicle-mounted power battery. The detection method of the present application is used to detect each battery cell of the power battery online, collect the voltage drop of each battery cell of the power battery under set conditions, and then analyze whether the battery cell is abnormal. If the battery cell has abnormal conditions during multiple consecutive detections, it can be judged that the battery cell has an internal short circuit problem. The detection method of the present application can accurately detect whether the power battery has an internal short circuit problem online. Multiple consecutive detections avoid the problem of misjudgment and missed judgment, improve the accuracy of judging the internal short circuit problem of the power battery, and improve the safety of the use of the power battery.

[0038] Specifically, Figure 1 As shown, the on-vehicle power battery internal short circuit online detection method of the present application is carried out according to the following steps:

[0039] S1. After the power battery has completed the set mileage, when the SOC of the power battery is within the set range, the voltage of each cell in the power battery is collected before and after the set rest time;

[0040] The present application performs multiple consecutive sampling of the cells of the power battery. In order to avoid the problem of errors caused by two consecutive samplings being too close, the present application sets the sampling conditions of the power battery, that is, a sampling analysis can be performed once the power battery completes a set mileage. The set mileage of the present application is 100km~200km, and 100km can be selected. For example, the first sampling analysis is performed when the vehicle equipped with the power battery travels 100km, the second sampling analysis is performed when the vehicle travels 200km, and the third sampling analysis is performed when the vehicle travels 300km, and so on.

[0041] The purpose of constructing the setting range of the SOC of the power battery is to perform sampling when the voltage drop is most obvious. The setting range of this application is 70% to 90%. When the SOC of the power battery is between 70% and 90%, the voltage drop of the power battery cell is most obvious. Performing voltage drop collection and detection within this setting range can minimize the error of data collection and improve the accuracy of internal short circuit judgment.

[0042] The present application also sets a limit on the set standing time for sampling. The set standing time of the present application is 2h to 6h. The standing time of the power battery is directly related to the accuracy of the voltage drop data collection. If the standing time is too short (less than 2h), the polarization of the battery cell is not completely eliminated. If the standing time is too long (greater than 6h), the accuracy of the statistical results of the data will be affected. By setting a suitable standing time, the error of data collection can be eliminated and the accuracy of the judgment result can be improved.

[0043] That is, in this application, after the power battery has completed the set mileage, the SOC of the power battery is within the set range, and the voltages of the power battery before and after the set rest time are collected, which are the starting voltage and the ending voltage respectively;

[0044] S2. Calculate the voltage drop of each battery cell based on the voltage of each battery cell before and after the set rest time;

[0045] The voltage drop of the battery cell during the detection process can be obtained through the above starting voltage and ending voltage, that is, the voltage drop is equal to the difference between the starting voltage and the ending voltage;

[0046] S3, comparing the voltage drop with the standard voltage drop to determine whether there is an abnormality. If the battery cell is abnormal for a set number of consecutive times, it is determined that the battery cell has an internal short circuit problem;

[0047] Under normal circumstances, the starting voltage must be greater than the ending voltage, that is, after the battery cell has been standing for a period of time, the voltage will definitely drop, but this drop is limited. By constructing a standard test, the voltage drop under normal circumstances, that is, the standard voltage drop, can be obtained;

[0048] By comparing the voltage drop with the standard voltage drop, it is possible to determine whether the battery cell has an abnormality during the detection process. However, a single abnormality does not necessarily mean that the battery cell has an internal short circuit problem. Therefore, the present application performs multiple consecutive tests and will only determine that there is an internal short circuit problem when the battery cell has multiple abnormalities in succession. This avoids the mistake of determining that there is an internal short circuit problem based on a single abnormality, and solves the problems of missed judgment and misjudgment in the prior art.

[0049] In some embodiments of the present application, this embodiment optimizes the above-mentioned step S3. Specifically, the method of comparing the voltage drop with the standard voltage drop to determine whether there is an abnormality is: comparing the voltage drop of the battery cell with the standard voltage drop. If the voltage drop exceeds the standard voltage drop, it is determined that the battery cell has an abnormality.

[0050] The standard voltage drop is the voltage drop collected by building a standard experiment. The standard voltage drop in this example is 100mv, that is, if the collected voltage drop exceeds 100mv, it is considered that the current battery cell is abnormal; if the collected battery cell voltage drop is less than or equal to 100mv, the current battery cell is considered normal.

[0051] In actual application, the standard voltage drop of battery cells of different specifications and models is different. The above 100mv corresponds to a certain type of power battery. Different types of power batteries can be collected by constructing standard tests.

[0052] In other embodiments of the present application, this embodiment further optimizes the above-mentioned step S3. Specifically, the method for determining whether the battery cell has an internal short circuit problem is as follows: if the battery cell is determined to be abnormal in at least two consecutive tests, it is determined that the battery cell has an internal short circuit problem.

[0053] If abnormal conditions are detected in the battery cells twice in a row, it can be determined that the power battery cells have an internal short circuit problem. Two consecutive abnormal detections can rule out accidental abnormal voltage drops and avoid misjudgment and missed judgments.

[0054] In actual application, after the power battery completes the set mileage, when the SOC of the power battery is within the set range, the voltage of each battery cell in the power battery before and after the set standing time is collected; the voltage drop of each battery cell is calculated based on the voltage of each battery cell before and after the set standing time; the voltage drop is compared with the standard voltage drop to determine whether there is an abnormality, if the voltage drop exceeds the standard voltage drop, then the battery cell is determined to have an abnormality, otherwise, there is no abnormality; if the battery cell is determined to be abnormal in at least two consecutive tests, then the battery cell is determined to have an internal short circuit problem, otherwise, there is no internal short circuit problem.

[0055] Taking NCM523 as an example, the normal battery is the battery that is normally produced and off the production line, and the internal short-circuit battery is a battery with 500μm metal particles built in. The two batteries are put on the vehicle for use in the same environment. The pre-static voltage and post-static voltage are collected every 100Km when the SOC is in the range of 70% to 90% and the static time is in the range of 2h to 6h. The voltage drop of the battery cell is calculated based on the pre-static voltage and post-static voltage. The normal battery meets the condition that the voltage drop does not exceed the standard voltage drop (100mv) twice in a row. The internal short-circuit battery is greater than the standard voltage drop of the normal battery after using 300kM, and it occurs ≥2 times in a row, indicating that the battery has an internal short circuit problem and severe self-discharge. The specific test conditions are shown in the following table:

[0056] Table 1: Normal battery and internal short circuit battery test comparison table

[0057]

[0058] The present application also provides an on-vehicle power battery internal short circuit online detection system, including a battery cell voltage acquisition module, a battery cell voltage drop acquisition module, a battery cell abnormality judgment module and a battery cell internal short circuit judgment module, the battery cell voltage acquisition module is used to collect the voltage of the battery cell when the power battery is at a set mileage, the power battery SOC is within a set range and the power battery is before and after a set standing time; the battery cell voltage drop acquisition module obtains the voltage drop based on the voltage of the battery cell before and after the set standing time collected by the battery cell voltage acquisition module; the battery cell abnormality judgment module is used to compare the voltage drop of the battery cell with the standard voltage drop and judge whether the battery cell has an abnormality; the battery cell internal short circuit judgment module is used to judge whether the battery cell has an internal short circuit problem when the battery cell has an abnormality for a set number of consecutive times.

[0059] Among them, the battery cell abnormality judgment module is used to compare the voltage drop of the battery cell with the standard voltage drop, and make a judgment that the battery cell is abnormal when the voltage drop exceeds the standard voltage drop, otherwise it is judged that the battery cell does not have an abnormality.

[0060] The battery cell internal short circuit judgment module is used to determine that the battery cell has an internal short circuit problem when the battery cell is abnormal for at least two consecutive times, otherwise it is used to determine that the battery cell does not have an internal short circuit problem.

[0061] The present application also provides a computer-readable storage medium on which is stored a program product capable of implementing the above-mentioned on-board power battery internal short circuit online detection method of the present specification. In some possible implementations, various aspects of the present application can also be implemented in the form of a program product, which includes a program code, and when the program product is run on a terminal device, the program code is used to enable the terminal device to execute the steps according to various exemplary implementations of the present application described in the above-mentioned "Exemplary Method" section of the present specification.

[0062] The program product stored in the storage medium of the present application may adopt a portable compact disk read-only memory (CD-ROM) and include program code, and can be run on a terminal device, such as a personal computer. However, the program product of the present application is not limited thereto, and in this document, a readable storage medium may be any tangible medium containing or storing a program, which may be used by or in combination with an instruction execution system, apparatus, or device.

[0063] The program product may use any combination of one or more readable media. The readable medium may be a readable signal medium or a readable storage medium. The readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples (non-exhaustive list) of readable storage media include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0064] Computer readable signal media may include data signals propagated in baseband or as part of a carrier wave, in which readable program code is carried. Such propagated data signals may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. Readable signal media may also be any readable medium other than a readable storage medium, which may send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, apparatus, or device.

[0065] The program code embodied on the readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wired, optical cable, RF, etc., or any suitable combination of the foregoing.

[0066] Program code for performing the operations of the present application may be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java, C++, etc., and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user computing device, partially on the user device, as a separate software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server. In the case of a remote computing device, the remote computing device may be connected to the user computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computing device (e.g., using an Internet service provider to connect through the Internet).

[0067] As another aspect, the present application also provides an electronic device capable of implementing the above-mentioned on-vehicle power battery internal short circuit online detection method.

[0068] Those skilled in the art will appreciate that various aspects of the present application may be implemented as a system, method or program product. Therefore, various aspects of the present application may be specifically implemented in the following forms, namely: a complete hardware implementation, a complete software implementation (including firmware, microcode, etc.), or a combination of hardware and software, which may be collectively referred to as "circuit", "module" or "system" herein.

[0069] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present application. The present application may have various changes and improvements without departing from the spirit and scope of the present application, and these changes and improvements fall within the scope of the present application to be protected. The scope of protection claimed in the present application is defined by the attached claims and their equivalents.

Claims

1. A method for online detection of internal short circuit of a vehicle power battery, characterized in that: include, After the power battery has completed the set mileage, when the SOC of the power battery is within the set range, the voltage of each cell in the power battery before and after the set rest time is collected; Calculate the voltage drop of each cell based on the voltage before and after the set rest time of each cell; The voltage drop is compared with the standard voltage drop to determine whether there is an abnormality. If the battery cell has an abnormality within a set number of consecutive times, it is determined that the battery cell has an internal short circuit problem.

2. The method for online detection of internal short circuit of a vehicle-mounted power battery according to claim 1, characterized in that: The set mileage is 100 km to 200 km.

3. The method for online detection of internal short circuit of a vehicle-mounted power battery according to claim 1, characterized in that: The setting range is 70% to 90%.

4. The method for online detection of internal short circuit of a vehicle-mounted power battery according to claim 1, characterized in that: The set standing time is 2h to 6h.

5. The method for online detection of internal short circuit of a vehicle power battery according to claim 1, characterized in that: The method of comparing the voltage drop with the standard voltage drop to determine whether an abnormality exists includes: comparing the voltage drop of the battery cell with the standard voltage drop, and if the voltage drop exceeds the standard voltage drop, determining that the battery cell has an abnormality.

6. The method for online detection of internal short circuit of a vehicle-mounted power battery according to claim 1, characterized in that: The method for determining whether the battery cell has an internal short circuit problem comprises: if the battery cell is determined to be abnormal in at least two consecutive detections, then determining that the battery cell has an internal short circuit problem.

7. An on-vehicle power battery internal short circuit online detection system, characterized in that: The detection system is used to operate according to any one of the on-vehicle power battery internal short circuit online detection methods as claimed in claims 1 to 6, including: A cell voltage collection module, which is used to collect the voltage of the cell before and after the power battery is at a set mileage, the power battery SOC is within a set range, and the power battery is at a set rest time; A cell voltage drop acquisition module, wherein the cell voltage drop acquisition module acquires the voltage drop based on the voltage of the cell before and after the set standing time acquired by the cell voltage acquisition module; A cell abnormality judgment module, which is used to compare the voltage drop of the cell with the standard voltage drop and judge whether the cell is abnormal; The battery cell internal short circuit judgment module is used to judge whether the battery cell has an internal short circuit problem when the battery cell is abnormal for a set number of consecutive times.

8. The on-vehicle power battery internal short circuit online detection system according to claim 7, characterized in that: The battery cell abnormality judgment module is used to compare the voltage drop of the battery cell with the standard voltage drop, and make a judgment that the battery cell is abnormal when the voltage drop exceeds the standard voltage drop, otherwise it makes a judgment that the battery cell is not abnormal.

9. The on-vehicle power battery internal short circuit online detection system according to claim 7, characterized in that: The battery cell internal short circuit judgment module is used to determine that the battery cell has an internal short circuit problem when the battery cell is abnormal for at least two consecutive times, otherwise it is used to determine that the battery cell does not have an internal short circuit problem.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores at least one program code, and the at least one program code is loaded and executed by the processor to implement the operations performed by the on-board power battery internal short circuit online detection method as described in any one of claims 1 to 6.

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