Battery thermal damage consistency test method, system, equipment and medium

Abstract

The present application discloses a battery thermal damage consistency test method, system, equipment and medium, the method comprising: obtaining a damaged battery sample; the damaged battery sample is obtained after being treated with thermal radiation damage, and the damaged battery sample includes multiple battery cells; using a mixed power pulse characteristic test method to test the internal resistance change value of each battery cell before and after being damaged by thermal radiation, and determining the internal resistance damage consistency result of the damaged battery sample according to the internal resistance change value; using a voltage drop test method to test the voltage drop value of each battery cell before and after being damaged by thermal radiation, and determining the voltage drop damage consistency result of the damaged battery sample according to the voltage drop value; according to the internal resistance damage consistency result and the voltage drop damage consistency result, the thermal damage consistency result of the damaged battery sample is obtained. This scheme can more comprehensively and accurately determine the thermal damage consistency result of the damaged battery sample, and provide good data support for the subsequent design and development of batteries.

Description

Technical Field

[0001] The present invention generally relates to the technical field of battery testing, and in particular to a battery thermal damage consistency testing method, system, equipment and medium. Background Art

[0002] With the rapid development of electric vehicles, lithium-ion batteries, as clean energy storage carriers for electric vehicles, have been increasingly used in daily vehicles due to their high energy density, excellent cycle life and low self-discharge capacity. However, in actual use, mechanical damage, fast charging damage, manufacturing damage, etc. lead to battery performance degradation and even explosion, which seriously affects the safety and reliability of the battery. Among them, when a fire occurs in surrounding vehicles, a large amount of heat is generated, causing adjacent vehicles to be subjected to thermal radiation, causing thermal runaway. In order to ensure the safety performance of the battery under extreme conditions, it is particularly important to conduct thermal damage consistency testing on the battery.

[0003] At present, the relevant technology can use external heating method, extrusion experiment and other methods to simulate the reaction of the battery under different thermal failure conditions. However, this scheme needs to rely on subjective experience, resulting in poor accuracy of battery thermal damage consistency test. Summary of the invention

[0004] In view of the above-mentioned defects or deficiencies in the prior art, it is desirable to provide a battery thermal damage consistency test method, system, device and medium.

[0005] In a first aspect, the present invention provides a battery thermal damage consistency testing method, the method comprising:

[0006] Obtaining a damaged battery sample; the damaged battery sample is obtained after being treated with thermal radiation damage, and the damaged battery sample includes a plurality of battery cells;

[0007] Using a hybrid power pulse characteristic test method to test the internal resistance change value of each battery cell before and after being damaged by thermal radiation, and determining the internal resistance damage consistency result of the damaged battery sample according to the internal resistance change value;

[0008] Using a voltage drop test method to test the voltage drop value of each battery cell before and after being damaged by thermal radiation, and determining the voltage drop damage consistency result of the damaged battery sample according to the voltage drop value;

[0009] The thermal damage consistency result of the damaged battery sample is obtained according to the internal resistance damage consistency result and the voltage drop damage consistency result.

[0010] In one embodiment, a hybrid power pulse characteristic test method is used to test the internal resistance change value of each battery cell after being damaged by thermal radiation, including:

[0011] Under a preset temperature, performing a standard cycle capacity test on each battery cell in the damaged battery sample to determine the battery rated capacity of each battery cell;

[0012] At a plurality of preset state of charge (SOC) points, performing HPPC process step tests on each battery cell according to the battery calibration capacity, and obtaining HPPC test results corresponding to each battery cell at each state of charge (SOC) point;

[0013] Fitting the HPPC test results corresponding to each state of charge (SOC) point to obtain a first internal resistance value of each battery cell;

[0014] Obtaining a second internal resistance value of each battery cell before being damaged by heat radiation;

[0015] The internal resistance variation value of each battery cell is obtained according to the first internal resistance value and the second internal resistance value.

[0016] In one embodiment, the HPPC process step test is performed on each battery cell to obtain the HPPC test result corresponding to each state of charge SOC point of the damaged battery sample, including:

[0017] At each preset state of charge (SOC) point, after standing for a preset time, the damaged battery sample is discharged at a first preset constant current value until the charge of the damaged battery sample reaches a target discharge capacity; the target discharge capacity is less than the rated capacity of the battery;

[0018] After standing for a first preset time, discharging the damaged battery sample at a second preset constant current value; the second preset constant current value is greater than the first preset constant current value;

[0019] After being left to stand for a first preset time, the damaged battery sample is charged with the second preset constant current value, and a HPPC test result of the damaged battery sample corresponding to the preset state of charge SOC point is recorded.

[0020] In one embodiment, determining the internal resistance damage consistency result of the damaged battery sample according to the internal resistance change value includes:

[0021] Determining an internal resistance change mean value according to the battery change values ​​of the battery cells;

[0022] Determining the internal resistance deviation of each battery cell before and after being damaged by thermal radiation based on the battery change value of each battery cell and the internal resistance change mean value;

[0023] Determining a target internal resistance deviation having a maximum value from the internal resistance deviations;

[0024] According to the target internal resistance deviation, an internal resistance damage consistency result of the damaged battery sample is determined.

[0025] In one embodiment, a voltage drop test is used to test the voltage drop value of each battery cell before and after being damaged by thermal radiation, including:

[0026] After each battery cell is left to stand for a second preset time, each battery cell is tested by a voltage drop test method to obtain a first voltage value of each battery cell;

[0027] Obtaining a second voltage value of each battery cell before being damaged by heat radiation;

[0028] The voltage drop value of each battery cell is obtained according to the first voltage value and the second voltage value.

[0029] In one embodiment, determining the voltage drop damage consistency result of the damaged battery sample according to the voltage drop value includes:

[0030] Determining a voltage drop average value according to the voltage drop values ​​of the battery cells;

[0031] Determining voltage deviations of the battery cells before and after being damaged by thermal radiation based on the voltage drop values ​​of the battery cells and the voltage drop average;

[0032] Determining a target voltage deviation with a maximum value from the voltage deviations;

[0033] The voltage drop damage consistency result of the damaged battery sample is determined according to the target voltage deviation.

[0034] In one embodiment, obtaining the thermal damage consistency result of the damaged battery sample according to the internal resistance damage consistency result and the voltage drop damage consistency result includes:

[0035] Determining a minimum value from the internal resistance damage consistency result and the voltage drop damage consistency result;

[0036] Comparing the minimum value with a preset threshold value;

[0037] When the minimum value is greater than the preset threshold, the thermal damage consistency result of the damaged battery sample is valid.

[0038] In a second aspect, an embodiment of the present application provides a battery thermal damage consistency test system, the system comprising:

[0039] An acquisition module, used for acquiring a damaged battery sample; the damaged battery sample is obtained after being treated with thermal radiation damage, and the damaged battery sample includes a plurality of battery cells;

[0040] A first determination module is used to test the internal resistance change value of each battery cell before and after being damaged by thermal radiation by using a hybrid power pulse characteristic test method, and determine the internal resistance damage consistency result of the damaged battery sample according to the internal resistance change value;

[0041] A second determination module is used to test the voltage drop value of each battery cell before and after being damaged by thermal radiation by a voltage drop test method, and determine the voltage drop damage consistency result of the damaged battery sample according to the voltage drop value;

[0042] A result determination module is used to obtain the thermal damage consistency result of the damaged battery sample according to the internal resistance damage consistency result and the voltage drop damage consistency result.

[0043] In a third aspect, an embodiment of the present application provides a computer device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the battery thermal damage consistency test method provided in the above embodiment.

[0044] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the battery thermal damage consistency test method provided in the above embodiment is implemented.

[0045] The embodiments of the present application provide a battery thermal damage consistency test method, system, equipment and medium, the method comprising: obtaining a damaged battery sample, the damaged battery sample being obtained after being treated with thermal radiation damage, the damaged battery sample comprising a plurality of battery cells, using a hybrid power pulse characteristic test method to test the internal resistance change value of each battery cell before and after being damaged by thermal radiation, determining the internal resistance damage consistency result of the damaged battery sample based on the internal group change value, and using a voltage drop test method to test the voltage drop value of each battery cell before and after being damaged by thermal radiation, determining the voltage drop damage consistency result of the damaged battery sample based on the voltage drop value, and then obtaining the thermal damage consistency result of the damaged battery sample based on the internal resistance damage consistency result and the voltage drop damage consistency result. Compared with the existing technology, on the one hand, this technical solution can more comprehensively evaluate the internal resistance change value by testing the battery cell using a hybrid power pulse characteristic test method, accurately determine the internal resistance damage consistency result based on the internal resistance change value, and quickly determine the voltage drop value of the battery cell through a voltage drop test method, thereby accurately determining the voltage drop damage consistency result, providing data guidance information for the subsequent determination of the thermal damage consistency result; on the other hand, based on the internal resistance damage consistency result and the voltage drop damage consistency result, the determined thermal damage consistency result can be made more accurate, providing good data support for the subsequent battery design and development. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0047] Figure 1 A schematic diagram of the application environment structure of the battery thermal damage consistency test system provided in an embodiment of the present application;

[0048] Figure 2 A schematic diagram of the structure of a battery thermal damage consistency test system provided in another embodiment of the present application;

[0049] Figure 3 A schematic diagram of a flow chart of a battery thermal damage consistency test method provided in an embodiment of the present application;

[0050] Figure 4 A schematic diagram of the structure of the temperature sensor of the battery provided in the embodiment of the present application;

[0051] Figure 5 A schematic diagram of a flow chart of a method for determining a change in internal resistance of each battery cell provided in an embodiment of the present application;

[0052] Figure 6 A schematic diagram of a flow chart of a method for determining a voltage drop value of each battery cell provided in an embodiment of the present application;

[0053] Figure 7 A schematic diagram of the structure of a battery thermal damage consistency test method provided in an embodiment of the present application;

[0054] Figure 8 A schematic diagram of the structure of a battery thermal damage consistency test device provided in an embodiment of the present application;

[0055] Fig. 9 A schematic diagram of the structure of a computer device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0056] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0057] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0058] The application environment of the battery thermal damage consistency test system provided in the embodiment of the present application can be found in Figure 1 The application environment includes a damaged battery sample 10, a heat radiation device 20, and a computer device 30. The computer device 30 establishes communication connections with the damaged battery sample 10 and the heat radiation device 20 respectively. The damaged battery sample 10 can be located above the heat radiation device during the heat radiation damage process.

[0059] The damaged battery sample 10 includes a plurality of battery cells 11, and the heat radiation device 20 includes a plurality of oil grids 21. The sizes of the oil grids can be the same or different. Gasoline can be placed in each oil grid to create an environment for thermal radiation damage to the battery.

[0060] It is understandable that the battery cells 11 in the damaged battery sample 10 may be of the same size or different sizes, and may be arranged in sequence, for example, 10 battery cells of the same size and properties may be provided, or 5 battery cells of the same size and properties may be provided. The damaged battery sample 10 may be provided in the whole vehicle for heat radiation damage treatment, or may be provided separately for heat radiation damage treatment.

[0061] See also Figure 2As shown, the battery to be damaged can be arranged in a battery pack in a vehicle layout state, and gasoline can be placed in the oil grids on the right, left, and bottom of the heat radiation device 20, and the gasoline is ignited and kept burning for a preset time, so as to perform heat radiation damage on the battery to be damaged and obtain a damaged battery cell 10. The preset time can be customized according to specific experimental requirements, for example, it can be 180s.

[0062] The computer device 30 is used to: use a mixed power pulse characteristic test method to test the internal resistance change value of each battery cell before and after being damaged by thermal radiation, and determine the internal resistance damage consistency result of the damaged battery sample based on the internal resistance change value; and use a voltage drop test method to test the voltage drop value of each battery cell before and after being damaged by thermal radiation, and determine the voltage drop damage consistency result of the damaged battery sample based on the voltage drop value; obtain the thermal damage consistency result of the damaged battery sample based on the internal resistance damage consistency result and the voltage drop damage consistency result.

[0063] The computer device 30 has data control and data processing functions, and may include a terminal for establishing communication connection between servers. The computer device 30 may be configured with test control software, which is used to control the entire test process, including the processing of collected data and the analysis of results, and is also responsible for recording test conditions and results and generating reports that meet specifications.

[0064] Optionally, the server may be a single server, or a server cluster or distributed system composed of several servers, or a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, content delivery networks (CDN), and big data and artificial intelligence platforms. An operating system may be running on the above-mentioned terminal, and the operating system may include but is not limited to Android system, IOS system, Linux system, Unix, Windows system, etc., and may also include a user interface (UI) layer, which may provide data display to the outside through the UI layer. In addition, a control instruction may be sent to the heat radiation device 20 based on an application programming interface (API), so that the heat radiation device 20 receives and responds to the control instruction, performs a corresponding heat radiation damage operation on the damaged battery, and obtains a damaged battery sample.

[0065] Among them, the server and terminal can be equipped with a microprocessor (MCU), memory (ROM, RAM), input and output interface (I / O), analog-to-digital converter (A / D), and large-scale integrated circuits such as shaping and driving.

[0066] In an exemplary embodiment, Figure 3 As shown, a battery thermal damage consistency test method is provided. The method is executed by a computer device, and can be executed by a terminal or a server alone, or by a terminal and a server together. In the embodiment of the present application, the method is applied to Figure 1 The computer device 30 in the example is used as an example to illustrate the method, which includes the following steps S201 to S204. Among them:

[0067] Step S201, obtaining a damaged battery sample; the damaged battery sample is obtained after being treated with thermal radiation damage, and the damaged battery sample includes a plurality of battery cells.

[0068] It should be noted that the damaged battery sample is a battery that has been damaged by thermal radiation. The damaged battery sample may be a lithium-ion battery, which includes a plurality of lithium-ion battery cells and may also include a lithium-ion battery module. The number of lithium-ion battery cells may be customized according to actual test requirements, for example, it may be set to 5, 8 or 10.

[0069] As a feasible method, in the process of obtaining the battery to be damaged, the battery to be damaged can be obtained first, and the battery to be damaged can be placed in the whole vehicle, and then the whole vehicle can be placed on a heat radiation device, or the oil grid at the bottom of the whole vehicle can be filled with gasoline, and then the gasoline can be ignited and kept burning for a preset time, so as to perform thermal radiation damage on the battery to be damaged and obtain a damaged battery sample.

[0070] As another achievable method, after obtaining the battery to be damaged, the battery to be damaged is placed in the vehicle, and then the vehicle is placed on a heat radiation device, which can be to fill the oil grid on the side of the vehicle with gasoline, and then ignite the gasoline and keep burning for a preset time, so as to perform heat radiation damage on the battery to be damaged and obtain a damaged battery sample. The preset time can be customized according to actual needs.

[0071] It is understandable that the degree and area of ​​thermal radiation damage to the battery of the entire vehicle may be different after the gasoline located in different oil grid positions is ignited. For example, when the gasoline in the oil grid located at the bottom of the vehicle burns, the bottom of the corresponding damaged battery sample may be damaged to a larger extent and area; when the gasoline in the oil grid located on the side of the vehicle burns, the side of the corresponding damaged battery sample may be damaged to a larger extent and area.

[0072] Step S202 , using a hybrid power pulse characteristic test method to test the internal resistance change value of each battery cell before and after being damaged by thermal radiation, and determining the internal resistance damage consistency result of the damaged battery sample according to the internal resistance change value.

[0073] Specifically, after obtaining the battery to be damaged, the damaged battery sample can be tested using a mixed power pulse characteristic test method to obtain the internal resistance value of each battery cell after being damaged by thermal radiation, and the internal resistance change value is determined based on the internal resistance value before being damaged by thermal radiation. The internal resistance change value is then analyzed to obtain the internal resistance damage consistency result of the damaged battery sample.

[0074] It should be noted that the internal resistance damage consistency result of the damaged battery sample refers to the consistency of these changes between different battery cells after the battery internal resistance changes in the damaged battery sample. It is very important for evaluating the overall performance, reliability and safety of the damaged battery sample.

[0075] Taking the damaged battery sample as a lithium-ion battery as an example, the Hybrid Pulse Power Characterization (HPPC) experiment, that is, for electrochemical energy storage systems such as lithium-ion batteries, can accurately obtain the internal resistance characteristics of the battery at different states of charge (SOC) through the HPPC experiment. The battery internal resistance value is one of the key indicators for measuring battery performance, which can include ohmic internal resistance and polarization internal resistance value. The ohmic internal resistance mainly comes from the resistance of the components such as the electrode material, electrolyte, and diaphragm inside the battery, while the polarization internal resistance value is related to the electrochemical reaction process inside the battery.

[0076] In order to study the effect of temperature on the HPPC characteristics of the battery or to ensure that the experiment is carried out under specific temperature conditions, temperature control equipment such as a thermostat is used. The thermostat can control the battery ambient temperature within a set range, such as between 25°C and 60°C, to simulate the performance of the battery in different working environments; see Figure 4 As shown, a temperature sensor can also be arranged on the damaged battery sample to measure the temperature through the temperature sensor to control it within a set range. The temperature sensor can be, for example, a K-type thermocouple temperature sensor. Among them, the damaged battery sample can be provided with temperature sensors at multiple points, and the multiple points can sequentially include four points corresponding to the labels: label 1 is the center point of the large surface, label 2 is the positive pole, label 3 is the negative pole, and label 4 is the side.

[0077] Optionally, the above system can also use a test device that can accurately control the charge and discharge current and voltage of the battery, and can have a high sampling frequency, so as to record the voltage, current, time and other data of the damaged battery sample during the test in real time. The internal resistance value of the battery after being damaged by thermal radiation is determined based on the voltage and current, so as to obtain the internal resistance change value before and after the thermal radiation damage based on the internal resistance value after the thermal radiation damage and the internal resistance value before the thermal radiation damage. After obtaining the internal resistance change value, the internal resistance change value can be analyzed to obtain the internal resistance damage consistency result of the damaged battery sample.

[0078] In this embodiment, a hybrid power pulse characteristic test method is used to test the internal resistance change value of each battery cell before and after thermal radiation damage, and the internal resistance damage consistency result of the damaged battery sample can be accurately determined based on the internal resistance change value, providing good data guidance information for the subsequent determination of the final damage consistency result.

[0079] Step S203, using a voltage drop test method to test the voltage drop value of each battery cell before and after being damaged by thermal radiation, and determining the voltage drop damage consistency result of the damaged battery sample according to the voltage drop value.

[0080] It should be noted that the voltage drop damage consistency result of the damaged battery sample refers to the consistency of the voltage drop between different battery cells in the damaged battery sample after the battery voltage drops. It is very important for evaluating the overall performance, reliability and safety of the damaged battery sample.

[0081] Optionally, the voltage drop test method may be a static discharge test method, a dynamic discharge test method, or a cycle test method. This embodiment does not impose any limitation on the manner of performing the voltage drop test on the damaged battery sample.

[0082] After obtaining the internal resistance change value, the internal resistance change value can be analyzed to obtain the internal resistance damage consistency result of the damaged battery sample.

[0083] Step S204, obtaining a thermal damage consistency result of the damaged battery sample according to the internal resistance damage consistency result and the voltage drop damage consistency result.

[0084] It should be noted that the thermal damage consistency results of damaged battery samples refer to the consistency of these temperature changes between different battery cells after the battery is damaged by heat due to thermal radiation. Thermal damage can be caused by external factors or internal factors. Internal factors can include degradation of electrode materials, electrolyte decomposition, diaphragm damage, etc. External factors can include excessive ambient temperature, excessive charging current, mechanical damage to the battery, etc.

[0085] Specifically, after obtaining the internal resistance damage consistency result and the voltage drop damage consistency result, determine the minimum value from the internal resistance damage consistency result and the voltage drop damage consistency result, and compare the minimum value with the preset threshold value; when the minimum value is greater than the preset threshold value, the thermal damage consistency result of the damaged battery sample is valid; when the minimum value is not greater than the preset threshold value, the thermal damage consistency result of the damaged battery sample is invalid. The preset threshold value can be customized according to actual test requirements, for example, it can be 90%.

[0086] For example, taking the internal resistance damage consistency result as S1 and the voltage drop damage consistency result as S2 as an example, the thermal damage consistency result S of the damaged battery sample can be calculated by the following formula:

[0087] S=min(S1,S2);

[0088] The battery thermal damage consistency test method provided in an embodiment of the present application includes: obtaining a damaged battery sample, the damaged battery sample is obtained after being treated with thermal radiation damage, the damaged battery sample includes multiple battery cells, using a mixed power pulse characteristic test method to test the internal resistance change value of each battery cell before and after being damaged by thermal radiation, determining the internal resistance damage consistency result of the damaged battery sample according to the internal group change value, and using a voltage drop test method to test the voltage drop value of each battery cell before and after being damaged by thermal radiation, determining the voltage drop damage consistency result of the damaged battery sample according to the voltage drop value, and then obtaining the thermal damage consistency result of the damaged battery sample according to the internal resistance damage consistency result and the voltage drop damage consistency result. Compared with the existing technology, on the one hand, this technical solution can more comprehensively evaluate the internal resistance change value by testing the battery cell using a hybrid power pulse characteristic test method, accurately determine the internal resistance damage consistency result based on the internal resistance change value, and quickly determine the voltage drop value of the battery cell through a voltage drop test method, thereby accurately determining the voltage drop damage consistency result, providing data guidance information for the subsequent determination of the thermal damage consistency result; on the other hand, based on the internal resistance damage consistency result and the voltage drop damage consistency result, the determined thermal damage consistency result can be made more accurate, providing good data support for the subsequent battery design and development.

[0089] In another exemplary embodiment of the present application, in order to accurately determine the internal resistance change value of each battery cell after being damaged by radiation, a hybrid power pulse characteristic test method can be used to test the internal resistance change value of each battery cell after being damaged by thermal radiation, such as Figure 5 As shown, the above step 202 is replaced by the following steps S301 to S305:

[0090] Step S301 : performing a standard cycle capacity test on each battery cell in a damaged battery sample at a preset temperature to determine the battery rated capacity of each battery cell.

[0091] Specifically, after the treated battery is subjected to thermal radiation damage, a damaged battery sample is obtained, and then the damaged battery sample after the test is left to stand for 7 days. Please refer to Table 1, set the HPPC test step according to the configuration parameters shown in Table 1 and execute the HPPC test process, first calibrate the capacity, determine the battery calibration capacity of each battery cell, and then obtain the HPPC test results corresponding to each battery cell at each state of charge SOC point. The configuration parameters can be set according to the charge and discharge characteristics of the battery itself, which may include sampling interval, skip condition, temperature, charge cut-off voltage, discharge cut-off voltage, first preset constant current value, and second preset constant current value. For example, the charge cut-off voltage can be 4.2 V, and the discharge cut-off voltage can be 2.7V. Among them, the first preset constant current value and the second preset constant current value are customized according to actual needs. The first preset constant current value is 0.33C, and the second preset constant current value is 1C, 1C=117A.

[0092] Table 1

[0093]

[0094] It should be noted that in the process of determining the battery calibration capacity, the first step is performed first: at the target temperature, the damaged battery sample is left to stand for a period of time. When the step length is greater than 1h, jump to the second step: at the preset target temperature, the damaged battery sample is discharged at the first preset constant current value (0.33C). When the discharge is processed to the discharge cut-off voltage (2.7V), that is, when the voltage is <2.7V, jump to the third step: at 25°C, the discharged damaged battery sample is left to stand for a preset time and then charged. When the step length is greater than 1h, jump to the fourth step; at 25°C, the damaged battery sample is charged at the first preset constant current value (0.33C). When the voltage is greater than 4.2V, it is converted to constant voltage. When the current is less than 0.05C, jump to the fifth step: repeat the above four steps, and record the average value of the last three rounds of discharge capacity as the battery calibration capacity C0. Among them, the sampling interval of the battery voltage in the above four steps is 1.

[0095] Step S302 , at a plurality of preset state of charge (SOC) points, HPPC process step tests are performed on each battery cell according to the battery calibration capacity to obtain the HPPC test results corresponding to each battery cell at each state of charge (SOC) point.

[0096] Step S303 , fitting the HPPC test results corresponding to each state of charge SOC point to obtain a first internal resistance value of each battery cell.

[0097] Step S304 , obtaining a second internal resistance value of each battery cell before being damaged by heat radiation.

[0098] Step S305 , obtaining the internal resistance change value of each battery cell according to the first internal resistance value and the second internal resistance value.

[0099] In the process of obtaining the HPPC test results corresponding to each state of charge SOC point, at each preset state of charge SOC point, after standing for a preset time, the damaged battery sample is discharged with a first preset constant current value until the charge of the damaged battery sample reaches a target discharge capacity; the target discharge capacity is less than the calibrated capacity of the battery; after standing for a first preset time, the damaged battery sample is discharged with a second preset constant current value; the second preset constant current value is greater than the first preset constant current value; after standing for a first preset time, the damaged battery sample is charged with the second preset constant current value, and the HPPC test results corresponding to the damaged battery sample at the preset state of charge SOC points are recorded.

[0100] It should be noted that after determining the battery calibration capacity C0, execute the sixth step: let the damaged battery sample stand for a period of time. When the step length is greater than 1h, jump to the seventh step: discharge the damaged battery sample with the first constant current value (0.33C) until the battery is discharged to the target discharge capacity (0.1C0). When the battery is discharged to the target discharge capacity (0.1C0), jump to the eighth step: let the damaged battery sample stand for the first preset time. When the step length is greater than 1h, jump to the ninth step: discharge the damaged battery sample with the first constant current value (0.33C) until the battery is discharged to the target discharge capacity (0.1C0). Add a short discharge pulse, that is, discharge the damaged battery sample with the second preset constant current value (1C). When the step length is greater than 10s, jump to step 10: let the damaged battery sample stand for the first preset time. When the step length is greater than 1h, jump to step 11: charge the damaged battery sample with the second preset constant current value (1C). When the step length is greater than 10s, jump to step 12: let the damaged battery sample stand for the first preset time. When the step length is greater than 1h, jump to step 13: repeat steps 7-12 for a total of 9 times. In the above steps 6-9, the sampling interval is 1, and in steps 9-12, the sampling interval is 0.1. The above steps 6-12 are all performed at the target temperature.

[0101] This pulse sequence will be repeated at different SOCs, such as performing such an HPPC pulse test every 10% SOC, from 100% SOC to 0% SOC. Then record the HPPC test results at the state of charge SOC points of 90% SOC, 80% SOC, 70% SOC, 60% SOC, ..., 10% SOC. The HPPC test result can be that the test equipment collects the voltage and current data of the battery according to the above sampling interval, and then performs fitting processing on it, and calculates the first internal resistance value of each battery cell according to the voltage and current. The first internal resistance value is the internal resistance value of the battery cell after being damaged by thermal radiation; the second internal resistance value is the internal resistance value of the battery cell before being damaged by thermal radiation.

[0102] After obtaining the second internal resistance value of each battery cell before being damaged by heat radiation, the first internal resistance value and the second internal resistance value are subjected to difference processing to obtain the internal resistance change value of each battery cell.

[0103] In this embodiment, by performing the HPPC process step test on the older battery cells in the damaged battery sample, the HPPC test results corresponding to each battery cell at each state of charge SOC point can be accurately obtained, and the HPPC test results corresponding to each state of charge SOC point are fitted to obtain the first internal resistance value of each battery cell, and then the second internal resistance value of each battery cell before being damaged by thermal radiation is obtained. According to the first internal resistance value and the second internal resistance value, the internal resistance change value of each battery cell is determined with higher accuracy.

[0104] In another exemplary embodiment of the present application, a specific implementation method of using a voltage drop test method to test the voltage drop value of each battery cell before and after being damaged by thermal radiation is also provided, such as Figure 6 As shown, the method may include the following steps S401 to S403:

[0105] Step S401 , after each battery cell is left to stand for a second preset time, each battery cell is tested by a voltage drop test method to obtain a first voltage value of each battery cell.

[0106] Step S402 , obtaining a second voltage value of each battery cell before being damaged by heat radiation.

[0107] Step S403: obtaining the voltage drop value of each battery cell according to the first voltage value and the second voltage value.

[0108] It should be noted that the above-mentioned first voltage value is the voltage value of the damaged battery sample after being damaged by thermal radiation, and the second voltage value is the voltage value of the damaged battery sample before being damaged by thermal radiation. The second preset time can be customized according to actual needs, for example, it can be 7 days.

[0109] Specifically, after obtaining the damaged battery sample, it can be put aside for 7 days, and then each battery cell can be tested using a voltage drop test to obtain a first voltage value of each battery cell, and obtain a second voltage value of each battery cell. The first voltage value and the second voltage value are subtracted to obtain a voltage drop value of each battery cell.

[0110] After obtaining the voltage drop value of each battery cell, determine the average voltage drop value according to the voltage drop value of each battery cell; determine the voltage deviation of each battery cell before and after thermal radiation damage based on the voltage drop value of each battery cell and the average voltage drop value; determine the target voltage deviation with the largest value from the voltage deviation; determine the voltage drop damage consistency result of the damaged battery sample based on the target voltage deviation.

[0111] For example, as shown in Table 2 below, ten battery cells with the same size and properties are selected as test samples, namely 1#, 2#, 3#, 4#, 5#, 6#, 7#, 8#, 9#, and 10#, and two battery cells with the same size and properties are selected as control samples, namely D1# and D2#. The two control samples are not subjected to heat radiation damage operation. The ten test samples are roasted and burned in the oil grid in the heat radiation device for 180s, and then the test samples and control samples are set aside for 7 days. Figure 7 As shown, the mixed power pulse characteristic test method is used to test the internal resistance change value of each battery cell before and after being damaged by thermal radiation. By obtaining the internal resistance values ​​of each comparison sample and each test sample after being damaged by thermal radiation, the internal resistance values ​​corresponding to the two comparison samples are 5.1mΩ, the internal resistance values ​​corresponding to the 1#-9# test samples are all 7.1mΩ, and the internal resistance value corresponding to the 10# is 7.2mΩ, so as to obtain the internal resistance increase value of the test sample after being damaged by thermal radiation, the internal resistance increase values ​​corresponding to the 1#-9# are all 2.1, and the internal resistance increase value corresponding to the 10# is 2.2. Then, the average increase value of the internal resistance is determined according to the increase value of the internal resistance of each battery cell, and then the deviation of each battery cell is calculated according to the increase value of the internal resistance of each battery cell and the average increase value of the internal resistance, and the maximum deviation value is selected as the target internal resistance deviation, and the target internal resistance deviation △1=2%, and then the internal resistance damage consistency result S1=1-△1=1-2%=98% of the damaged battery sample is obtained.

[0112] The voltage drop test was used to test the voltage drop values ​​of each battery cell before and after the test sample was left for 7 days. The voltage drop values ​​corresponding to No. 1-9 were all 55.2mV, and the voltage drop value corresponding to No. 10 was 55.3mV. The average voltage drop value was determined based on the voltage drop values ​​of each battery cell, and then the deviation of each battery cell was calculated based on the voltage drop values ​​of each battery cell and the average internal resistance voltage drop value. The largest deviation value was selected as the target voltage deviation, and the target voltage deviation △2=3%. Then the voltage drop damage consistency result of the damaged battery sample was obtained, S2=1-△2=1-3%=97%.

[0113] After obtaining the internal resistance damage consistency result S1 and the voltage drop damage consistency result S2, the thermal damage consistency result S of the damaged battery sample is determined to be min(S1, S2) = 97%. The thermal damage consistency result S is compared with the preset threshold of 90%. Since 97%>90%, the thermal damage consistency result of the damaged battery sample is valid.

[0114]

[0115] In the embodiments of the present application, on the one hand, by testing the battery cell in a hybrid power pulse characteristic test method, the internal resistance change value can be more comprehensively evaluated, and the internal resistance damage consistency result can be accurately determined based on the internal resistance change value, and the voltage drop value of the battery cell can be quickly determined through a voltage drop test method, thereby accurately determining the voltage drop damage consistency result, providing data guidance information for the subsequent determination of the thermal damage consistency result; on the other hand, based on the internal resistance damage consistency result and the voltage drop damage consistency result, the determined thermal damage consistency result can be made more accurate, providing good data support for the subsequent design and development of batteries.

[0116] Based on the same inventive concept, the embodiment of the present application also provides a battery thermal damage consistency test device for implementing the battery thermal damage consistency test method involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more battery thermal damage consistency test device embodiments provided below can refer to the limitations of the battery thermal damage consistency test method above, and will not be repeated here.

[0117] In an exemplary embodiment, Figure 8 As shown, a battery thermal damage consistency test device is provided, comprising:

[0118] The acquisition module 710 is used to acquire a damaged battery sample; the second voltage value damaged battery sample is obtained after being processed by thermal radiation damage, and the second voltage value damaged battery sample includes a plurality of battery cells;

[0119] The first determination module 720 is used to test the internal resistance change value of each battery cell of the second voltage value before and after being damaged by thermal radiation by using a hybrid power pulse characteristic test method, and determine the internal resistance damage consistency result of the battery sample damaged by the second voltage value according to the internal resistance change value of the second voltage value;

[0120] The second determination module 730 is used to test the voltage drop value of each battery cell of the second voltage value before and after being damaged by thermal radiation by using a voltage drop test method, and determine the voltage drop damage consistency result of the second voltage value damaged battery sample according to the second voltage value voltage drop value;

[0121] The result determination module 740 is used to obtain a thermal damage consistency result of a second voltage value damaged battery sample according to the second voltage value internal resistance damage consistency result and the second voltage value voltage drop damage consistency result.

[0122] As an optional implementation manner, the first determining module 720 is specifically configured to:

[0123] Under a preset temperature, performing a standard cycle capacity test on each battery cell in the second voltage value damaged battery sample to determine the battery rated capacity of each battery cell of the second voltage value;

[0124] At a plurality of preset state of charge (SOC) points, performing an HPPC step test on each battery cell of the second voltage value according to the battery calibration capacity, and obtaining an HPPC test result corresponding to each battery cell of the second voltage value at each state of charge (SOC) point;

[0125] Fitting the HPPC test results corresponding to each state of charge SOC point of the second voltage value to obtain the first internal resistance value of each battery cell of the second voltage value;

[0126] Obtaining a second internal resistance value of each battery cell of the second voltage value before being damaged by heat radiation;

[0127] According to the first internal resistance value at the second voltage value and the second internal resistance value at the second voltage value, the internal resistance change value of each battery cell at the second voltage value is obtained.

[0128] As an optional implementation manner, the first determining module 720 is further configured to:

[0129] At each preset state of charge SOC point, after standing for a preset time, the second voltage value damaged battery sample is discharged at a first preset constant current value until the charge amount of the second voltage value damaged battery sample reaches a target discharge capacity; the second voltage value target discharge capacity is less than the second voltage value battery calibrated capacity;

[0130] After being left still for a first preset time, the damaged battery sample of the second voltage value is discharged at a second preset constant current value; the second preset constant current value is greater than the first preset constant current value of the second voltage value;

[0131] After standing for a first preset time, the second voltage value damaged battery sample is charged with a second voltage value and a second preset constant current value, and the HPPC test result of the second voltage value damaged battery sample corresponding to the second voltage value preset state of charge SOC point is recorded.

[0132] As an optional implementation manner, the first determining module 720 is further configured to:

[0133] Determining an internal resistance change mean value according to the battery change value of each battery cell of the second voltage value;

[0134] Determine the internal resistance deviation of each battery cell of the second voltage value before and after being damaged by heat radiation based on the battery change value of each battery cell of the second voltage value and the mean value of the internal resistance change of the second voltage value;

[0135] Determining a target internal resistance deviation with a maximum value from the second voltage value internal resistance deviations;

[0136] According to the second voltage value target internal resistance deviation, the internal resistance damage consistency result of the second voltage value damaged battery sample is determined.

[0137] As an optional implementation manner, the second determining module 730 is specifically configured to:

[0138] After each battery cell of the second voltage value is left to stand for a second preset time, each battery cell of the second voltage value is tested by a voltage drop test method to obtain a first voltage value of each battery cell of the second voltage value;

[0139] Obtaining a second voltage value of each battery cell before being damaged by heat radiation;

[0140] According to the first voltage value and the second voltage value, the voltage drop value of each battery cell of the second voltage value is obtained.

[0141] As an optional implementation manner, the second determining module 730 is further configured to:

[0142] Determine a voltage drop average value according to the voltage drop values ​​of each battery cell of the second voltage value;

[0143] Determine the voltage deviation of each battery cell of the second voltage value before and after being damaged by heat radiation based on the voltage drop value of each battery cell of the second voltage value and the average voltage drop of the second voltage value;

[0144] Determining a target voltage deviation with a maximum value from the second voltage value voltage deviations;

[0145] According to the second voltage value target voltage deviation, a voltage drop damage consistency result of the second voltage value damaged battery sample is determined.

[0146] As an optional implementation, the result determination module 740 is specifically configured to:

[0147] Determine a minimum value from the second voltage value internal resistance damage consistency result and the second voltage value voltage drop damage consistency result;

[0148] Comparing the second voltage minimum value with a preset threshold value;

[0149] When the second voltage value minimum value is greater than the second voltage value preset threshold value, the thermal damage consistency result of the second voltage value damaged battery sample is valid.

[0150] Among them, by implementing this implementation method, on the one hand, by testing the battery cell using a hybrid power pulse characteristic test method, it is possible to more comprehensively evaluate the internal resistance change value, accurately determine the internal resistance damage consistency result based on the internal resistance change value, and quickly determine the voltage drop value of the battery cell through a voltage drop test method, thereby accurately determining the voltage drop damage consistency result, providing data guidance information for the determination of subsequent thermal damage consistency results; on the other hand, based on the internal resistance damage consistency result and the voltage drop damage consistency result, the determined thermal damage consistency result can be made more accurate, providing good data support for the subsequent design and development of batteries.

[0151] In an exemplary embodiment, a computer device is provided. The computer device may be a server or a terminal. The internal structure diagram thereof may be as follows: Fig. 9 As shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, referred to as I / O) and a communication interface. Among them, the processor, the memory and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store video tag processing data. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a battery thermal damage consistency test method is implemented.

[0152] Those skilled in the art will understand that Fig. 9 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0153] In an exemplary embodiment, a computer device is further provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above-mentioned method embodiments when executing the computer program.

[0154] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program, and when the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0155] In an exemplary embodiment, a computer program product is provided, including a computer program, and when the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0156] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0157] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM may be in various forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM).

[0158] The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. The non-relational database may include a distributed database based on blockchain, etc., but is not limited thereto. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but is not limited thereto.

[0159] The technical features of the above embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0160] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A battery thermal damage consistency test method, characterized in that: The battery thermal damage consistency test method comprises: Obtaining a damaged battery sample; the damaged battery sample is obtained after being treated with thermal radiation damage, and the damaged battery sample includes a plurality of battery cells; The internal resistance change value of each battery cell before and after being damaged by thermal radiation is tested by a hybrid power pulse characteristic test method, and the internal resistance damage consistency result of the damaged battery sample is determined according to the internal resistance change value, including: Determining an internal resistance change mean value according to the internal resistance change values ​​of each battery cell; Determining the internal resistance deviation of each battery cell before and after being damaged by thermal radiation based on the internal resistance change value of each battery cell and the internal resistance change mean value; Determining a target internal resistance deviation having a maximum value from the internal resistance deviations; According to the target internal resistance deviation, determine the internal resistance damage consistency result S1 of the damaged battery sample = 1-target internal resistance deviation; The voltage drop test is used to test the voltage drop value of each battery cell before and after being damaged by thermal radiation, and the voltage drop damage consistency result of the damaged battery sample is determined according to the voltage drop value, including: Determining a voltage drop average value according to the voltage drop values ​​of the battery cells; Determining voltage deviations of the battery cells before and after being damaged by thermal radiation based on the voltage drop values ​​of the battery cells and the voltage drop average; Determining a target voltage deviation with a maximum value from the voltage deviations; According to the target voltage deviation, determining the voltage drop damage consistency result S2 of the damaged battery sample = 1-target voltage deviation; According to the internal resistance damage consistency result and the voltage drop damage consistency result, the thermal damage consistency result of the damaged battery sample is obtained, including: Determining a minimum value from the internal resistance damage consistency result and the voltage drop damage consistency result; Comparing the minimum value with a preset threshold value; When the minimum value is greater than the preset threshold, the thermal damage consistency result of the damaged battery sample is valid.

2. The battery thermal damage consistency testing method according to claim 1, characterized in that: The hybrid power pulse characteristic test method is used to test the internal resistance change value of each battery cell after being damaged by thermal radiation, including: Under a preset temperature, performing a standard cycle capacity test on each battery cell in the damaged battery sample to determine the battery rated capacity of each battery cell; At a plurality of preset state of charge (SOC) points, performing HPPC process step tests on each battery cell according to the battery calibration capacity, and obtaining HPPC test results corresponding to each battery cell at each state of charge (SOC) point; Fitting the HPPC test results corresponding to each state of charge (SOC) point to obtain a first internal resistance value of each battery cell; Obtaining a second internal resistance value of each battery cell before being damaged by heat radiation; The internal resistance variation value of each battery cell is obtained according to the first internal resistance value and the second internal resistance value.

3. The battery thermal damage consistency testing method according to claim 2, characterized in that: Performing HPPC process step tests on each battery cell respectively to obtain the HPPC test results corresponding to each state of charge (SOC) point of the damaged battery sample, including: At each preset state of charge (SOC) point, after standing for a preset time, the damaged battery sample is discharged at a first preset constant current value until the charge of the damaged battery sample reaches a target discharge capacity; the target discharge capacity is less than the rated capacity of the battery; After standing for a first preset time, discharging the damaged battery sample at a second preset constant current value; the second preset constant current value is greater than the first preset constant current value; After being left to stand for a first preset time, the damaged battery sample is charged with the second preset constant current value, and a HPPC test result of the damaged battery sample corresponding to the preset state of charge SOC point is recorded.

4. The battery thermal damage consistency testing method according to claim 1, characterized in that: The voltage drop test method is used to test the voltage drop value of each battery cell before and after being damaged by thermal radiation, including: After each battery cell is left to stand for a second preset time, each battery cell is tested by a voltage drop test method to obtain a first voltage value of each battery cell; Obtaining a second voltage value of each battery cell before being damaged by heat radiation; The voltage drop value of each battery cell is obtained according to the first voltage value and the second voltage value.

5. A battery thermal damage consistency test system, characterized in that: include: An acquisition module, used for acquiring a damaged battery sample; the damaged battery sample is obtained after being treated with thermal radiation damage, and the damaged battery sample includes a plurality of battery cells; The first determination module is used to test the internal resistance change value of each battery cell before and after being damaged by thermal radiation by using a hybrid power pulse characteristic test method, and determine the internal resistance damage consistency result of the damaged battery sample according to the internal resistance change value, including: Determining an internal resistance change mean value according to the internal resistance change values ​​of each battery cell; Determining the internal resistance deviation of each battery cell before and after being damaged by thermal radiation based on the internal resistance change value of each battery cell and the internal resistance change mean value; Determining a target internal resistance deviation having a maximum value from the internal resistance deviations; According to the target internal resistance deviation, determine the internal resistance damage consistency result S1 of the damaged battery sample = 1-target internal resistance deviation; The second determination module is used to test the voltage drop value of each battery cell before and after being damaged by thermal radiation by using a voltage drop test method, and determine the voltage drop damage consistency result of the damaged battery sample according to the voltage drop value, including: Determining a voltage drop average value according to the voltage drop values ​​of the battery cells; Determining voltage deviations of the battery cells before and after being damaged by thermal radiation based on the voltage drop values ​​of the battery cells and the voltage drop average; Determining a target voltage deviation with a maximum value from the voltage deviations; According to the target voltage deviation, determining the voltage drop damage consistency result S2 of the damaged battery sample = 1-target voltage deviation; A result determination module is used to obtain the thermal damage consistency result of the damaged battery sample according to the internal resistance damage consistency result and the voltage drop damage consistency result, including: Determining a minimum value from the internal resistance damage consistency result and the voltage drop damage consistency result; Comparing the minimum value with a preset threshold value; When the minimum value is greater than the preset threshold, the thermal damage consistency result of the damaged battery sample is valid.

6. A computer device comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the battery thermal damage consistency test method according to any one of claims 1 to 4.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the battery thermal damage consistency testing method described in any one of claims 1 to 4 is implemented.

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