Overcurrent temperature rise test method and overcurrent temperature rise test system of battery cell

Abstract

The application discloses a kind of overcurrent temperature rise test method and overcurrent temperature rise test system of electric core, wherein the overcurrent temperature rise test method of electric core, comprising: determining the test sample corresponding to the target electric core to be detected;Test sample includes: test core package, test cover plate assembly and test bus bar, the tab of test core package is connected with the pole of test cover plate assembly, the pole of test cover plate assembly is connected with test bus bar, test bus bar is short-circuited at preset short-circuit position;Determine the temperature test area in test sample;Based on test bus bar, test current is accessed to test sample, and detection temperature data of temperature test area under the action of test current is obtained;According to test current and detection temperature data, the thermal response data of test sample is determined.The above scheme can effectively avoid the interference of current to the state of test sample in the test process, reduce the change of the performance of test sample after test, so as to meet the requirement of test accuracy for multiple tests.

Description

Technical Field

[0001] This application relates to the field of battery testing, and in particular to a method and system for testing the overcurrent temperature rise of a battery cell. Background Technology

[0002] The Cells Contact System (CCS) is a critical component responsible for the electrical connection between battery cells. The cells are connected to the busbar of the CCS via positive and negative terminals. During charging and discharging, the cells must withstand high currents exceeding their nominal current. This causes the busbar of the CCS to heat up under the influence of this high current. The heat generated by the busbar is conducted to the cells, potentially causing the cell temperature to exceed the safe range, thus affecting the safety and lifespan of the cells. To facilitate the development of reasonable thermal management strategies and ensure the reliability of the battery cells within the specified temperature range, it is necessary to test the temperature rise of the battery cells when they are heated and recirculated through the external busbar. Related technologies directly use actual target battery cells and their matching busbars for overcurrent temperature rise testing. However, during the testing process, the high temperatures generated by the busbars may affect the performance of the target battery cells, making it difficult for them to meet the accuracy requirements of multiple tests. Summary of the Invention In view of this, this application provides a method and system for testing the overcurrent temperature rise of a battery cell, so as to at least partially solve the above-mentioned technical problems.

[0003] In a first aspect, embodiments of this application provide a method for testing the overcurrent temperature rise of a battery cell, comprising: Identify the test sample corresponding to the target cell to be tested; the test sample includes: a test cell pack, a test cover plate assembly and a test bus, the tabs of the test cell pack are connected to the terminals of the test cover plate assembly, the test bus is connected to the terminals of the test cover plate assembly, and the test bus is short-circuited at a preset short-circuit position; Determine the temperature testing area in the test sample; Based on the test current connected to the test sample through the test bus, the temperature data of the temperature test area under the action of the test current is obtained; The thermal response data of the test sample is determined based on the test current and the detection temperature data.

[0004] By employing the above scheme, a test sample corresponding to the target battery cell is constructed, and a test current is applied under short-circuited test bus conditions. This simulates the heat conduction process from the matching bus to the target battery cell under actual overcurrent conditions. By collecting temperature data from the temperature testing area and combining this data with the test current, the thermal response characteristics of the test sample under different test currents can be accurately analyzed. This testing process effectively avoids interference from the current on the test sample's state, reduces changes in the test sample's performance after testing, and thus meets the accuracy requirements of multiple tests.

[0005] Optionally, in some embodiments of this application, the temperature testing area includes: a first testing area and a second testing area, wherein the first testing area is located on the testing busbar; the second testing area is located on the testing core package; and the detected temperature data includes first temperature data and second temperature data. The step of obtaining the temperature data of the temperature test area under the action of the test current by connecting the test current to the test sample based on the test bus includes: When the ambient temperature of the test sample meets the first temperature condition, a test current is connected through the test bus to collect the corresponding first temperature data of the first test area under the action of the test current. If the first temperature data meets the first preset condition, the second temperature data corresponding to the second test area under the test current is collected.

[0006] By adopting the above scheme, when the first temperature data meets the first preset condition, the second temperature data corresponding to the second test area under the test current can be collected. This can effectively eliminate the interference of busbar temperature instability on the detection of the second temperature data, ensuring that the second temperature data can accurately reflect the actual temperature rise characteristics of the core during the heat conduction process, and guaranteeing the accuracy and reliability of the cell thermal response verification.

[0007] Optionally, in some embodiments of this application, the method further includes: When the static temperature of the test sample meets the second temperature condition, the next set of test currents is connected to the test sample through the test bus.

[0008] By adopting the above scheme and controlling the static temperature to meet the second temperature condition, it can be ensured that each test is carried out under the same benchmark, thereby eliminating the interference of residual heat after the previous test current test on subsequent tests and ensuring the independence and accuracy of the detection temperature data corresponding to each test current.

[0009] Optionally, in some embodiments of this application, determining the thermal response data of the test sample based on the test current and the detected temperature data includes: Based on the detection temperature data corresponding to each of the test currents, the mapping data between the detection temperature data of the temperature test area and the test current is obtained; Based on the mapping data, the target location where the test sample meets the temperature threshold condition under different test currents is determined.

[0010] By adopting the above scheme and establishing a mapping relationship between the detected temperature data and the test current, it is convenient to analyze the impact of different tests on the temperature distribution of the test sample, and then accurately locate the target position where the temperature response is most significant under each test current, thereby providing an accurate and reliable basis for the subsequent thermal management design of the battery cell.

[0011] Optionally, in some embodiments of this application, the temperature testing area further includes: a third testing area, the third testing area being located between the two poles of the test cover assembly, and the detected temperature data including third temperature data; the method further includes: The sample temperature of the test sample is determined based on the third temperature data of the third test area under the action of the test current.

[0012] By adopting the above scheme and testing the third temperature data in the third test area, the overall temperature state of the test sample under overcurrent conditions can be more comprehensively reflected, avoiding the one-sidedness of sample temperature evaluation caused by focusing only on the temperature of a single area. Furthermore, by combining the third temperature data and the second temperature data, the thermal response data of the test sample can be determined more accurately, which is beneficial for adjusting the subsequent cell thermal management design.

[0013] Optionally, in some embodiments of this application, the current values ​​between the test currents are gradient-distributed.

[0014] By adopting the above scheme and setting the test current to a gradient distribution, the temperature change pattern of the test sample under different test currents can be obtained, thereby accurately simulating the thermal response data of the target cell under test and providing reliable data support for subsequent cell thermal management design.

[0015] Optionally, in some embodiments of this application, before obtaining the detection temperature data of the temperature test area under the action of the test current by connecting the test current to the test sample based on the test bus, the method further includes: Provide a pre-test sample; the pre-test sample includes: two test buses, the two test buses being configured to be shorted together at a preset short-circuit position; The test bus is sequentially connected to multiple sets of pre-test currents to obtain the pre-test temperature data of the test bus under the action of the pre-test currents; Based on the pre-test current and the pre-test temperature data, select the pre-test current corresponding to multiple pre-test temperature data that meet the pre-test temperature conditions as the test current.

[0016] By adopting the above scheme, the heating of the busbar under different pre-test currents can be measured. This allows for the selection of representative pre-test currents as test currents, effectively avoiding blind testing and preventing arbitrary selection of test currents. This improves the efficiency and accuracy of the entire testing process and ensures that the test results truly reflect the heating characteristics of the busbar under different current conditions.

[0017] Secondly, embodiments of this application also provide a battery cell overcurrent temperature rise testing system, comprising: a test sample and a testing device; the testing device is used to test the test sample according to the battery cell overcurrent temperature rise testing method described above. The test sample corresponds to the target battery cell to be tested. The test sample includes a test cell pack, a test cover assembly, and a test bus. The tabs of the test cell pack are connected to the terminals of the test cover assembly, and the test bus is connected to the terminals of the test cover assembly. The test bus is short-circuited at a preset short-circuit position.

[0018] By adopting the above scheme, through the cooperation of the test sample and the test device, the test device tests the test sample according to the overcurrent temperature rise test method of the battery cell as described above. This can effectively avoid the interference of current on the state of the test sample during the test process, reduce the change in the performance of the test sample after the test, and thus meet the requirements of test accuracy for multiple tests.

[0019] Optionally, in some embodiments of this application, the testing apparatus includes: a test power supply; The test bus includes: a first connection part, a shorting part, and a second connection part; the first connection part is connected to the test power supply, the second connection part is connected to the terminal, the shorting part is located between the first connection part and the second connection part, and the shorting parts of the two test buses are shorted together; The distance between the two poles of the test cover assembly is L1; in the same test busbar, the distance between the first connecting part and the second connecting part is L2, and the distance between the shorting part and the second connecting part is L3; The ratio of L2 to L1 ranges from 0.55 to 0.65, and the ratio of L3 to L1 ranges from 0.3 to 0.4.

[0020] By adopting the above scheme and limiting the ratio of L2 to L1 and the ratio of L3 to L1, the position layout of the shorting part in the test bus can be optimized. This makes the shorting operation easy to implement and ensures that the current path formed after the shorting is reasonable. In this way, the heating situation of the matching bus can be better simulated, thereby more realistically simulating the temperature rise characteristics of the target cell under test under actual overcurrent conditions, which helps to improve the accuracy and reliability of the test results.

[0021] Optionally, in some embodiments of this application, the testing apparatus further includes: a first temperature sensor and a plurality of second temperature sensors; The first temperature sensor is located on the test bus; Multiple second temperature sensors are spaced apart on the core package along a direction parallel to the axis of the pole post.

[0022] By adopting the above scheme and setting the first and second temperature sensors, the temperature changes at different locations of the test busbar and test core package can be monitored in real time, thereby accurately obtaining the temperature rise changes in each region during the current flow process.

[0023] Optionally, in some embodiments of this application, the size specifications of the test bus are the same as the size specifications of the matching bus of the target cell to be tested; By adopting the above solution and limiting the size and specifications of the test bus, it is possible to ensure that the resistance, heat generation, and other properties of the test bus are consistent with those of the matching bus in the actual application scenario during the test process. This avoids the impact of differences in size and specifications between the test bus and the actual matching bus on the accuracy of the thermal response data.

[0024] Optionally, in some embodiments of this application, the dimensions of the test core package and test cover assembly are the same as those of the target cell to be tested.

[0025] By adopting the above scheme, and by ensuring that the size and specifications of the test core package and test cover plate assembly are the same as those of the target cell to be tested, the interference caused by structural differences of the test sample on the test results can be effectively eliminated, ensuring that the obtained thermal response data can truly reflect the thermal response characteristics of the target cell to be tested. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1This is a schematic diagram of the main steps of an overcurrent temperature rise test method for a battery cell provided in an embodiment of this application; Figure 2 This is a schematic diagram of the test sample in an overcurrent temperature rise test method for a battery cell provided in an embodiment of this application; Figure 3 This is a schematic diagram of the structure of an overcurrent temperature rise testing system for a battery cell provided in an embodiment of this application; Figure 4 This is a schematic diagram of the structure of the test bus and shorting component in an overcurrent temperature rise test system for a battery cell provided in an embodiment of this application; Figure 5 This is a front view of a test sample in an overcurrent temperature rise testing system for battery cells provided in an embodiment of this application; Figure 6 This is a schematic diagram of a structure for performing a pre-test current test using a test bus, provided in an embodiment of this application. Figure 7 This is a schematic diagram of the structure used in the embodiment of this application to verify the target battery cell to be tested.

[0028] Explanation of reference numerals in the attached figures: 200. Test sample; 210. Test core package; 211. Main body; 212. Electrode tab; 220. Test cover assembly; 221. Top cover; 222. Electrode post; 230. Test busbar; 231. First connection part; 232. Shorting part; 233. Second connection part; 240. Shorting component; 310. Target cell to be tested; 311. Housing; 312. Target cell package; 320. Matching busbar; 400. Test power supply. Detailed Implementation

[0029] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Furthermore, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0031] In this application, "at least one" means one or more, and "more than one" means two or more. "One or more", "at least one of the following", or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0032] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0033] The Cells Contact System (CCS) is a critical component responsible for the electrical connection between battery cells. The cells are connected to the busbar of the CCS via positive and negative terminals. During charging and discharging, the cells must withstand high currents exceeding their nominal current. This causes the busbar of the CCS to heat up under the influence of the high current. The heat generated by the busbar is conducted to the cells, potentially causing the cell temperature to exceed the safe range. For example, the electrolyte inside the cell may evaporate, side reactions may occur due to heat, and the separator material may shrink due to heat, leading to internal short circuits within the cell. All of these issues can affect the safety and lifespan of the cells.

[0034] To facilitate the development of reasonable thermal management strategies and ensure the reliability of the battery cells within the specified temperature range, it is necessary to test the temperature rise of the battery cells when they are heated and recirculated through the external busbar. Related technologies directly use actual target battery cells and their matching busbars for overcurrent temperature rise testing. However, during the testing process, the high temperatures generated by the busbars may affect the performance of the target battery cells, making it difficult for them to meet the accuracy requirements of multiple tests. To address the above technical problems, firstly, this application provides a method for testing the overcurrent temperature rise of a battery cell, please refer to... Figure 1The overcurrent temperature rise test method for battery cells includes the following main steps S110 to S140.

[0035] Step S110: Determine the test sample corresponding to the target cell to be tested; the test sample includes: test cell pack, test cover plate assembly and test bus, the tabs of the test cell pack are connected to the terminals of the test cover plate assembly, the test bus is connected to the terminals of the test cover plate assembly, and the test bus is short-circuited at a preset short-circuit position.

[0036] Step S120: Determine the temperature test area in the test sample.

[0037] Step S130: Based on the test bus, the test current is connected to the test sample to obtain the temperature data of the temperature test area under the action of the test current.

[0038] Step S140: Determine the thermal response data of the test sample based on the test current and detection temperature data.

[0039] This application embodiment detects the overcurrent temperature rise of a test sample and determines the overcurrent temperature rise detection result of the target battery cell to be tested based on the detection results of the test sample. Please refer to [link to relevant documentation]. Figure 2 , Figure 2 This is a schematic diagram of the test sample in an overcurrent temperature rise test method for a battery cell provided in an embodiment of this application. (See attached diagram.) Figure 2 As shown, the test sample 200 includes a test core package 210, a test cover assembly 220, and a test bus 230. The test core package 210 has the same structure as the core package in the target cell 310 under test; the test cover assembly 220 has the same structure as the cover assembly in the target cell 310 under test; and the test bus 230 has the same material and size as the matching bus 320 of the target cell 310 under test, thus ensuring matching thermal conductivity characteristics. After the test bus 230 is short-circuited at a preset short-circuit position, a test current simulating actual overcurrent conditions is applied through the test power supply 400, causing the test bus 230 to generate the heat required for the test. The connection between the test bus 230 and the terminal 222 simulates the connection state between the target cell 310 under test and the matching bus 320 under real-world conditions, thereby reflecting the heat conduction process from the matching bus 320 to the target cell 310 under test.

[0040] It should be noted that the test bus 230 does not input or output current to the test cell 210; its function is solely to simulate the effect of busbar heating on the cell during actual use. By applying test current without involving the test cell 210 in charging and discharging, and only allowing the test bus 230 to generate heat, interference from the current on the internal state of the test cell 210 during testing can be effectively avoided, ensuring the consistency and repeatability of test conditions for each test. Simultaneously, this method significantly reduces the error risk caused by changes in the performance of the test sample 200 after testing, improving the reliability of temperature rise data.

[0041] The temperature test area is used to collect and detect temperature data during overcurrent temperature rise testing. Based on the temperature data collected in the temperature test area, the temperature change of the test sample after the test current is applied can be obtained. The temperature test area can be arranged in at least one of the test core package 210, the test cover assembly 220, and the test busbar 230 to monitor the distribution and conduction path of heat in the test sample 200. Thermal response data is used to characterize the temperature change of the test sample. Thermal response data can include temperature distribution at different locations of the test sample 200, the rate of temperature rise over time, etc., thereby obtaining information on heat generation, transfer, and accumulation in the test sample 200 under overcurrent conditions.

[0042] By employing the above scheme, a test sample 200 corresponding to the target cell 310 under test is constructed. With the test bus 230 short-circuited, a test current is applied, simulating the heat conduction process from the matching bus 320 to the target cell 310 under actual overcurrent conditions. By collecting temperature data from the temperature test area and combining this data with the test current, the thermal response characteristics of the test sample 200 under different test currents can be accurately analyzed. This testing process effectively avoids interference from the current on the state of the test sample 200, reducing changes in the performance of the test sample 200 after testing, thus meeting the accuracy requirements of multiple tests.

[0043] Furthermore, the same test sample 200 can be used for verification of multiple sets of different test currents, and there is no need to prepare complete battery cells, which significantly improves testing efficiency and reduces testing costs.

[0044] Based on the above testing methods, the structural design of the battery cell can be fed back, providing accurate and reliable reference for subsequent improvements in battery cell thermal management design. This reduces the risk of safety failure of the target battery cell 310 during use due to overheating and internal short circuit.

[0045] In some embodiments of this application, the ratio of the test current to the nominal current of the target cell under test ranges from 1.3 to 2, or it can be flexibly adjusted according to actual test requirements and the characteristics of the target cell 310 under test.

[0046] In some embodiments of this application, the temperature testing area includes: a first testing area and a second testing area, wherein the first testing area is located on the test busbar 230; the second testing area is located on the test core package 210; and the detected temperature data includes first temperature data and second temperature data.

[0047] Step S130 includes the following specific steps: S131: When the ambient temperature of the test sample meets the first temperature condition, the test current is connected through the test bus 230 to collect the corresponding first temperature data of the first test area under the action of the test current.

[0048] S132: When the first temperature data meets the first preset condition, collect the second temperature data corresponding to the second test area under the test current.

[0049] The first test area is used to collect the first temperature data of the test bus 230, and the second test area is used to collect the second temperature data of the test core 210. By setting the first test area and the second test area, the temperature data of the test bus 230 and the test core 210 under the action of the test current can be obtained independently and reliably.

[0050] The first temperature condition characterizes the initial temperature conditions that the test sample must meet before the test current is applied to it. For example, to ensure the accuracy of overcurrent temperature rise detection of the test sample, it is necessary to control the correspondence between the ambient temperature of the test sample and the operating environment temperature of the target cell 310 under test. For example, the first temperature condition can be the temperature of the operating environment of the target cell 310 under test, ensuring that the initial temperature conditions of the test sample 200 are consistent with the actual operating conditions, and avoiding additional errors introduced by the ambient temperature difference.

[0051] The first preset condition represents the conditions that the first temperature data must meet before the second temperature data is collected. The first preset condition can be that the first temperature data reaches a stable state, or that the first temperature data is heated to a specific threshold to ensure that the test sample enters the steady-state heat conduction stage. At this time, the second temperature data collected can truly reflect the heat transfer from the drain to the core.

[0052] By adopting the above scheme, when the first temperature data meets the first preset condition, the second temperature data corresponding to the second test area under the test current can be collected. This can effectively eliminate the interference of busbar temperature instability on the detection of the second temperature data, ensuring that the second temperature data can accurately reflect the actual temperature rise characteristics of the core during the heat conduction process, and guaranteeing the accuracy and reliability of the cell thermal response verification.

[0053] In some specific implementations, the first preset condition may be that the first temperature data reaches a stable state and the duration meets a first preset duration. The value of the first preset duration may range from 20 minutes to 40 minutes.

[0054] In some specific implementations, multiple first test areas are spaced apart along the extension direction of the test bus; please refer to [link / reference]. Figure 3 , Figure 3 This is a schematic diagram of the structure of an overcurrent temperature rise testing system for a battery cell provided in an embodiment of this application. Figure 3 As shown, exemplarily, the first test area on one busbar includes points T2 and T3, and the first test area on another busbar includes points T4 and T5. T2 and T4 are located near preset short-circuit positions N1 and N2, respectively, while T3 and T5 are located at the connection between the test busbar 230 and the pole post 222. By setting up these multiple first test areas, temperature distribution information at different locations on the test busbar can be obtained, thereby identifying gradient changes along the heat transfer path.

[0055] In one example of this application, since the test bus 230 transfers heat to the test cover assembly 220 and the test core package 210 through the pole 222, the first preset condition can be that the temperature of at least one of T3 and T5 reaches a stable state and the duration meets the first preset duration, thereby ensuring that the test bus 230 provides a stable heat input to the test core package 210 and the test cover assembly 220 when the second temperature data is collected.

[0056] In one example of this application, please refer to Figure 4 , Figure 4 This is a schematic diagram of the structure of the test bus and short-circuit component in an overcurrent temperature rise test system for a battery cell provided in an embodiment of this application; as shown. Figure 4 As shown, along the extension direction of the test bus 230, the distance between T3 and T5 is equal to the distance L1 between the two poles 222. The distance between the test current connection point M1 and T3 is L2, the distance between the test current connection point M2 and T5 is L2, the distance between T2 and T3 is L3, and the distance between T4 and T5 is L3. The ratio of L2 to L1 ranges from 0.55 to 0.65, and the ratio of L3 to L1 ranges from 0.3 to 0.4.

[0057] For some specific implementation methods, please refer to Figure 3 The test core package 210 is provided with two sets of second test areas, which are set corresponding to two pole posts 222. Each set of second test areas contains multiple second test areas spaced apart along a direction parallel to the axis of the pole post 222, which are used to monitor the temperature response of the core package near the corresponding pole post 222.

[0058] In the application example, please refer to Figure 5 , Figure 5 This is a front view of a test sample in an overcurrent temperature rise testing system for battery cells provided in an embodiment of this application; as shown... Figure 5 As shown, the first group of second test areas includes points T6, T8, and T9, and the second group of second test areas includes points T7, T10, and T11. T6 and T7 are located on their respective tabs 212, and T8 and T10 are located near the edge of the core package body 211. The distance between T8 and T10 and the edge of the core package body 211 can range from 5mm to 9mm. T9 and T10 are located in the center area of ​​the core package body 211. The ratio of the distance between T9 and T6 to the height of the core package body 211 can range from 0.25 to 0.5, and the ratio of the distance between T11 and T7 to the height of the core package body 211 can also range from 0.25 to 0.5.

[0059] In some specific implementations, the ambient temperature can be provided by a temperature chamber, which can accurately simulate the working environment of the target cell 310 under test (such as the internal environment of a battery pack), ensuring that the test sample 200 starts testing under the set constant temperature conditions, thereby effectively controlling variables and improving the accuracy of test data.

[0060] In one example of this application, the ambient temperature range provided by the temperature chamber is 25°C to 65°C. Testing within this temperature range simulates the actual operating environment of the target battery cell 310 under real-world conditions, thereby ensuring that the test data is representative.

[0061] In some embodiments of this application, different chamber temperatures can be set according to the actual usage environment of the target cell 310 to be tested, so as to evaluate the thermal response characteristics of the test sample 200 under different ambient temperatures.

[0062] In some embodiments of this application, the method further includes the following specific steps: S133: When the static temperature of the test sample meets the second temperature condition, the next set of test currents is connected to the test sample through the test busbar.

[0063] The settling temperature can be a temperature characterizing the test sample after the current is stopped and it has been allowed to cool down. The second temperature condition can be a characterizing the initial temperature condition that the test sample must meet before the next set of test currents is applied to it. For example, the second temperature condition can be the same as the first temperature condition, or the difference between the second temperature condition and the first temperature condition can be within a preset temperature difference range to ensure that the initial thermal state of the test sample is similar before different sets of tests are applied.

[0064] By adopting the above scheme and controlling the static temperature to meet the second temperature condition, it can be ensured that each test is carried out under the same temperature reference, thereby eliminating the interference of residual heat after the previous test current test on subsequent tests and ensuring the independence and accuracy of the detection temperature data corresponding to each test current.

[0065] In one example of this application, after the previous set of test current tests is completed, the test sample needs to be allowed to cool completely so that the static temperature of the test sample can meet the second temperature condition.

[0066] In some specific implementations, the static temperature corresponding to the test sample 200 can be the temperature of at least one of the test core package 210, the test cover assembly 220 and the test busbar 230, or the static temperature corresponding to the test sample 200 can be the average temperature of the entire test sample 200.

[0067] In some specific implementations, the test current ranges from 50A to 1000A, covering current input scenarios under rapid charging and discharging as well as extreme operating conditions.

[0068] In other embodiments of this application, the effect of continuous application of different test currents and heat accumulation on the thermal response data of the test sample 200 can also be tested.

[0069] In some embodiments of this application, step S140 includes the following specific steps: Step S141: Based on the detection temperature data corresponding to each test current, obtain the mapping data between the detection temperature data and the test current of the temperature test area.

[0070] Step S142: Determine the target location of the test sample that meets the temperature threshold condition under different test currents based on the mapping data.

[0071] The mapping data between the detected temperature data and the test current is used to characterize the temperature change pattern of the temperature test area under different test currents.

[0072] Temperature threshold conditions are criteria used to define the distribution of detection temperature data in different temperature test areas. For example, a temperature threshold condition can be at least one extremely hot location in different temperature test areas, or it can be a safe temperature value that the test sample 200 can withstand.

[0073] By adopting the above scheme and establishing a mapping relationship between the detected temperature data and the test current, it is convenient to analyze the impact of different tests on the temperature distribution of the test sample 200, and then accurately locate the target position with the most significant temperature response under each test current, thereby providing an accurate and reliable basis for the subsequent thermal management design of the battery cell.

[0074] In some embodiments of this application, reference is made to Figure 3 The temperature testing area also includes a third testing area, located between the two poles 222 of the test cover assembly 220, where the detected temperature data includes the third temperature data; the method also includes the following steps: S134: Determine the sample temperature of the test sample based on the third temperature data of the third test area under the action of the test current.

[0075] The sample temperature is temperature data used to characterize the overall temperature of the test sample; the third test area corresponds to the actual temperature detection location of the target cell under test during actual use. By collecting the third temperature data, the overall temperature of the test cell pack 210 and the test cover assembly 220 can be obtained.

[0076] By adopting the above scheme, the third temperature data from the third test area can more comprehensively reflect the overall temperature state of the test sample 200 under overcurrent conditions, avoiding the one-sidedness of temperature evaluation caused by focusing only on the temperature of a single area. Furthermore, by combining the third and second temperature data, the thermal response data of the test sample 200 can be determined more accurately, which is beneficial for adjusting the subsequent cell thermal management design.

[0077] In one example of this application, reference is made to Figure 3 The third test area includes T1.

[0078] In some embodiments of this application, the current values ​​between the test currents exhibit a gradient distribution.

[0079] By adopting the above scheme and setting the test current to a gradient distribution, the temperature change law of the test sample 200 under different test currents can be obtained, thereby accurately simulating the thermal response data of the target cell under test and providing reliable data support for subsequent cell thermal management design.

[0080] In some specific implementations, the test current can be at least one of 50A, 100A, 150A, 200A, 250A, 300A, 350A, 400A, 450A, 500A, 550A, 600A, 650A, 700A, 750A, 800A, 850A, 900A, 950A, and 1000A.

[0081] In some embodiments of this application, prior to step S130, the overcurrent temperature rise test method for the battery cell further includes: S101: Provide a pre-test sample; the pre-test sample includes: two test buses, the two test buses 230 are configured to be shorted together at a preset shorting position.

[0082] S102: Connect multiple sets of pre-test currents to the test bus in sequence to obtain the pre-test temperature data of the test bus under the action of the pre-test current.

[0083] S103: Based on the pre-test current and pre-test temperature data, select the pre-test current corresponding to multiple pre-test temperature data that meet the pre-test temperature conditions as the test current.

[0084] Please see Figure 6 , Figure 6 This is a schematic diagram of a structure for performing a pre-test current test using a test bus, as provided in an embodiment of this application. Figure 6 As shown, the pre-test sample contains only two test buses 230 and a shorting member 240 between the two test buses 230.

[0085] Pre-test temperature data is used to characterize the temperature of the test busbar in the pre-test sample under the action of pre-test current; pre-test temperature conditions can be the criteria for determining whether the pre-test temperature data meets the test requirements; for example, the pre-test temperature conditions can be multiple temperature data that meet the preset temperature gradient, or multiple temperature data that do not exceed the busbar safety temperature threshold.

[0086] By adopting the above scheme, the heating of the busbar 230 under different pre-test currents can be measured. This allows for the selection of representative pre-test currents as test currents, effectively avoiding blindness in the testing process and preventing arbitrary selection of test currents. This improves the efficiency and accuracy of the entire testing work and ensures that the test results truly reflect the heating characteristics of the busbar 230 under different current conditions.

[0087] It should be noted that step S102 above is also performed in an incubator, and the temperature of the incubator used in step S102 is the same as that in step S130, to ensure that the environmental conditions of the pre-test process are consistent with those of the formal test, thereby eliminating the influence of the temperature difference of the incubator on the test results.

[0088] In some specific implementations, the pre-test temperature data can be the temperature data of the test bus in the pre-test sample reaching a stable temperature under the action of the pre-test current for a duration that meets a second preset time. The value of the second preset time can be in the range of 20 min to 40 min.

[0089] In one example of this application, the pre-test temperature data can be the temperature at the corresponding pole 222 connection position in the test bus 230.

[0090] In some specific implementations, the pre-test temperature conditions can be at least one of 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, and 200°C, to ensure that the pre-test temperature can cover the high-current thermal conditions that the target cell 310 under test may face.

[0091] The following is a typical embodiment of the overall process of the overcurrent temperature rise test method for battery cells provided in this application.

[0092] St101: Provides a pre-test sample; the pre-test sample includes: two test buses configured to be shorted together at a preset shorting position.

[0093] St102: Connect multiple sets of pre-test currents to the test bus in sequence to obtain the pre-test temperature data of the test bus under the action of the pre-test current.

[0094] St103: Based on the pre-test current and pre-test temperature data, select multiple pre-test currents that meet the pre-test temperature conditions as test currents.

[0095] St104: Determine the test sample corresponding to the target cell to be tested; the test sample includes: test cell pack, test cover assembly and test bus, the tabs of the test cell pack are connected to the terminals of the test cover assembly, the test bus is connected to the terminals of the test cover assembly, and the test bus is short-circuited at the preset short-circuit position.

[0096] St105: Determine the temperature testing area in the test sample.

[0097] St106: Based on the test busbar connecting the test current to the test sample, the temperature data of the temperature test area under the action of the test current is obtained.

[0098] St107: Determine the thermal response data of the test sample based on the test current and detection temperature data.

[0099] Testing and Verification The target cell 310 to be tested is a lithium iron phosphate cell, model number 230; the length, width and height of the cell are 170*207*53mm, and the distance between the terminals 222 is 150mm; the matching bus 320 of the target cell 310 to be tested has a size of 40*120mm and is made of aluminum.

[0100] The present application will be specifically described below through specific embodiments. The following embodiments are only some embodiments of the present application and are not intended to limit the present application.

[0101] A test sample 200, identical in material and specifications to the target cell 310 and its matching busbar 320, is provided. The test sample 200 includes a test cell pack 210, a test cover assembly 220, and a test busbar 230. The tabs 212 of the test cell pack 210 are connected to the terminals 222 of the test cover assembly 220, and the test busbar 230 is connected to the terminals 222 of the test cover assembly 220. The test busbars 230 are short-circuited at preset short-circuit positions. Within the same test busbar 230, the distance between the preset short-circuit position and points T3 / T5 is 55mm, and the distance between the current access position and points T3 / T5 is 90mm. In the height direction of the cell pack, the distances between T8 and T10 and the edge of the cell pack are 10mm respectively; T9 and T11 are located in the middle of the cell pack body. Temperature sensors are respectively arranged on T1~T11.

[0102] Test sample 200 was placed in a temperature chamber maintained at a constant temperature of 50℃. The test power supply 400 was connected via the current input of the test bus 230, and pre-test currents of 200A, 250A, and 300A were sequentially applied. After the temperatures at points T3 and T5 stabilized and were maintained for 30 minutes, the detection temperature data corresponding to each temperature test area (T1~T11) were acquired. Table 1 shows the detection temperature data corresponding to T1~T11 for test sample 200 under different pre-test currents.

[0103] Table 1

[0104] The following verification is performed using the target cell 310 to be tested and its matching bus 320. The target cell 310 to be tested is a real cell, which includes a casing 311 and an electrolyte. That is, the target cell package 312 of the target cell 310 to be tested can be charged and discharged normally.

[0105] Reference Figure 7 Referring to the connection method of the test sample 200, connect the target cell 310, the matching bus 320, the temperature sensor and the test power supply 400 accordingly, wherein the matching bus 320s are not short-circuited.

[0106] Test sample 200 was placed in a temperature chamber maintained at a constant temperature of 50℃. Pre-test currents of 200A, 250A, and 300A were sequentially connected through the matching busbar 320. After the temperatures at points T3 and T5 stabilized and were maintained for 30 minutes, the corresponding test temperature data for each temperature test area (T1~T11) were acquired. Table 2 shows the test temperature data for the target cell 310 and the matching busbar 320 at different pre-test currents, corresponding to T1~T11.

[0107] Table 2

[0108] Based on the test data in Table 1, it can be seen that the temperature of each test area increases with the increase of the test current. T6 and T7 are the hottest locations in the test core package 210, while for T8 to T11, T8 and T10 have a higher probability of exhibiting higher temperatures under different test currents. Based on the test data in Table 2, it can be seen that T6, T7, T8, and T9 are the hottest locations in the target core package 312 of the target cell 310 under test. Obviously, the test results of the test data in Table 1 and Table 2 are basically consistent. Therefore, the test method of this application can accurately simulate the temperature distribution of the core package in the target cell 310 under test, and can provide a reliable basis for the thermal management design of the target cell 310 under test.

[0109] Secondly, referring to Figure 3 This application provides an overcurrent temperature rise testing system for battery cells, including: a test sample 200 and a testing device; the testing device is used to test the test sample 200 according to the overcurrent temperature rise testing method for battery cells as described above.

[0110] Among them, the test sample 200 corresponds to the target cell 310 to be tested. The test sample 200 includes: test cell pack 210, test cover assembly 220 and test bus 230. The tabs 212 of the test cell pack 210 are connected to the terminals 222 of the test cover assembly 220. The test bus 230 is connected to the terminals 222 of the test cover assembly 220. The test bus 230 is short-circuited at a preset short-circuit position.

[0111] By adopting the above scheme, through the cooperation of test sample 200 and test device, the test device tests test sample 200 according to the overcurrent temperature rise test method of the battery cell as described above. This can effectively avoid the interference of current on the state of test sample 200 during the test, reduce the change in the performance of test sample 200 after the test, and thus meet the requirements of test accuracy for multiple tests.

[0112] In some embodiments of this application, reference is made to Figure 3The testing device includes a test power supply 400. The test bus 230 includes a first connection part 231, a shorting part 232, and a second connection part 233; the first connection part 231 is connected to the test power supply 400, the second connection part 233 is connected to the terminal 222, the shorting part 232 is located between the first connection part 231 and the second connection part 233, and the shorting parts 232 of the two test buses 230 are shorted together.

[0113] Reference Figure 5 The distance between the two poles 222 of the test cover assembly 220 is L1; in the same test busbar 230, the distance between the first connecting part 231 and the second connecting part 233 is L2, and the distance between the shorting part 232 and the second connecting part 233 is L3. The ratio of L2 to L1 ranges from 0.55 to 0.65, and the ratio of L3 to L1 ranges from 0.3 to 0.4.

[0114] The first connection part 231 simulates the connection position between the matching bus 320 and the adjacent battery cell or external circuit, the second connection part 233 simulates the connection position between the matching bus 320 and the target battery cell 310 to be tested, and the short-circuit part 232 is used to realize the short-circuit of the two test buses 230 at the preset short-circuit position, thereby forming a current loop.

[0115] By adopting the above scheme and limiting the ratio of L2 to L1 and the ratio of L3 to L1, the position layout of the shorting part 232 in the test bus 230 can be optimized. This makes the shorting operation easy to implement and ensures that the current path formed after the shorting is reasonable. In this way, the heating situation of the matching bus 320 can be better simulated, thereby more realistically simulating the temperature rise characteristics of the target cell 310 under actual overcurrent conditions, which helps to improve the accuracy and reliability of the test results.

[0116] In some specific implementation methods, refer to Figure 5 The first connecting part 231 is provided with a connecting hole, which is used to achieve a stable electrical connection with the output terminal of the test power supply 400 by means of bolts or plugs; the shorting part 232 is provided with a shorting hole, which is used to achieve a reliable shorting connection with the shorting component 240 by means of bolts or plugs; more specifically, the connecting hole, the shorting hole and the connection position of the test bus 230 and the pole 222 are on the same straight line.

[0117] In some embodiments of this application, the testing apparatus further includes: a first temperature sensor and a plurality of second temperature sensors; the first temperature sensor is disposed on the test bus 230; and the plurality of second temperature sensors are spaced apart in the core package along the axial direction of the parallel pole post 222.

[0118] Each first temperature sensor corresponds to a first test area, and each second temperature sensor corresponds to a second test area. (Refer to...) Figure 3 That is, the first temperature sensor is arranged on T2, T3, T4 and T5 respectively, and the second temperature sensor is arranged on T6, T7, T8, T9, T10 and T11 respectively.

[0119] By adopting the above scheme and setting the first and second temperature sensors, the temperature changes at different locations of the test busbar 230 and the test core package 210 can be monitored in real time, thereby accurately obtaining the temperature rise changes in each region during the current flow process.

[0120] In some specific embodiments, the first temperature sensors are spaced apart along the extension direction of the busbar, for example, they can be located at the second connection portion 233 and the shorting portion 232. The second temperature sensors can be spaced apart along the axial direction of the electrode post 222, for example, these second temperature sensors can be respectively arranged at the tab 212, the edge of the test core package 210, the middle of the test core package 210, etc., so as to obtain the diffusion and accumulation of heat in the test core package 210.

[0121] In some embodiments of this application, the testing device further includes a third temperature sensor, which is disposed on the top cover 221 of the test cover assembly 220 and between the two poles 222 of the test cover assembly 220, for monitoring the temperature change on the surface of the top cover 221.

[0122] Specifically, the third temperature sensor corresponds to the third test area, as shown in the reference. Figure 3 That is, the third temperature sensor is arranged in T1.

[0123] In some embodiments of this application, the dimensions of the test bus 230 are the same as those of the matching bus 320 of the target cell 310 to be tested.

[0124] It is understandable that the matching bus 320 is a connection structure that matches the target battery cell 310 under test in practical applications.

[0125] By adopting the above solution and limiting the size of the test bus 230, it can be ensured that the resistance, heat generation, etc. of the test bus 230 are consistent with those of the matching bus 320 in the actual application scenario during the test. This avoids the accuracy of thermal response data being affected by the size difference between the test bus 230 and the actual matching bus 320.

[0126] In some embodiments of this application, the dimensions of the test core package 210 and the test cover assembly 220 are the same as those of the target cell 310 to be tested.

[0127] It is understood that the size specifications of the target cell 310 to be tested include the size parameters of the cover assembly, core package, etc. By ensuring that the size specifications of the test sample 200 are the same as those of the target cell 310 to be tested, it can be ensured that the test core package 210 and the test cover assembly 220 have the same heat transfer characteristics as the target cell 310 to be tested.

[0128] By adopting the above scheme, by limiting the size and specifications of the test core package 210 and the test cover assembly 220 to be the same as the size and specifications of the target cell 310 to be tested, the interference caused by the structural difference of the test sample 200 on the test results can be effectively eliminated, ensuring that the obtained thermal response data can truly reflect the thermal response characteristics of the target cell 310 to be tested.

[0129] The embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for testing the overcurrent temperature rise of a battery cell, characterized in that, include: Identify the test sample corresponding to the target battery cell to be tested; The test sample includes: a test core package, a test cover plate assembly, and a test bus. The tabs of the test core package are connected to the posts of the test cover plate assembly, and the test bus is connected to the posts of the test cover plate assembly. The test bus is short-circuited at a preset short-circuit position. Determine the temperature testing area in the test sample; Based on the test current connected to the test sample through the test bus, the temperature data of the temperature test area under the action of the test current is obtained; The thermal response data of the test sample is determined based on the test current and the detection temperature data.

2. The overcurrent temperature rise test method for battery cells according to claim 1, characterized in that, The temperature testing area includes: a first testing area and a second testing area, wherein the first testing area is located on the testing busbar; the second testing area is located on the testing core package; and the detected temperature data includes first temperature data and second temperature data. The step of obtaining the temperature data of the temperature test area under the action of the test current by connecting the test current to the test sample based on the test bus includes: When the ambient temperature of the test sample meets the first temperature condition, a test current is connected through the test bus to collect the corresponding first temperature data of the first test area under the action of the test current. If the first temperature data meets the first preset condition, the second temperature data corresponding to the second test area under the test current is collected.

3. The overcurrent temperature rise test method for battery cells according to claim 2, characterized in that, The method further includes: When the static temperature of the test sample meets the second temperature condition, the next set of test currents is connected to the test sample through the test bus.

4. The overcurrent temperature rise test method for battery cells according to claim 2, characterized in that, The step of determining the thermal response data of the test sample based on the test current and the detected temperature data includes: Based on the detection temperature data corresponding to each of the test currents, the mapping data between the temperature data and the test current in the temperature test area is obtained; Based on the mapping data, the target location where the test sample meets the temperature threshold condition under different test currents is determined.

5. The overcurrent temperature rise test method for a battery cell according to any one of claims 1 to 4, characterized in that, The temperature testing area further includes a third testing area, which is located between the two poles of the test cover assembly, and the detected temperature data includes the third temperature data; the method further includes: The sample temperature of the test sample is determined based on the third temperature data of the third test area under the action of the test current.

6. The overcurrent temperature rise test method for a battery cell according to any one of claims 1 to 4, characterized in that, The current values ​​between the test currents exhibit a gradient distribution.

7. The overcurrent temperature rise test method for a battery cell according to any one of claims 1 to 4, characterized in that, Before obtaining the temperature data of the temperature test area under the action of the test current by connecting the test current to the test sample based on the test bus, the method further includes: Provide a pre-test sample; the pre-test sample includes: two test buses, the two test buses being configured to be shorted together at a preset short-circuit position; The test bus is sequentially connected to multiple sets of pre-test currents to obtain the pre-test temperature data of the test bus under the action of the pre-test currents; Based on the pre-test current and the pre-test temperature data, select the pre-test current corresponding to multiple pre-test temperature data that meet the pre-test temperature conditions as the test current.

8. A battery cell overcurrent temperature rise testing system, characterized in that, include: Test sample (200) and test apparatus; the test apparatus is used to test the test sample (200) according to the overcurrent temperature rise test method of the battery cell as described in any one of claims 1 to 7; The test sample (200) corresponds to the target cell (310) to be tested. The test sample (200) includes: a test cell pack (210), a test cover assembly (220), and a test bus (230). The tab (212) of the test cell pack (210) is connected to the terminal (222) of the test cover assembly (220). The test bus (230) is connected to the terminal (222) of the test cover assembly (220). The test bus (230) is short-circuited at a preset short-circuit position.

9. The overcurrent temperature rise testing system for battery cells according to claim 8, characterized in that, The testing device includes: a test power supply (400); The test bus (230) includes: a first connecting part (231), a shorting part (232), and a second connecting part (233); the first connecting part (231) is connected to the test power supply (400), the second connecting part (233) is connected to the terminal (222), the shorting part (232) is located between the first connecting part (231) and the second connecting part (233), and the shorting parts (232) of the two test buses (230) are shorted together; The distance between the two poles (222) of the test cover assembly (220) is L1; in the same test busbar (230), the distance between the first connecting part (231) and the second connecting part (233) is L2, and the distance between the shorting part (232) and the second connecting part (233) is L3; The ratio of L2 to L1 ranges from 0.55 to 0.65, and the ratio of L3 to L1 ranges from 0.3 to 0.

4.

10. The overcurrent temperature rise testing system for battery cells according to claim 9, characterized in that, The testing device also includes: a first temperature sensor and multiple second temperature sensors; The first temperature sensor is located on the test bus (230); A plurality of second temperature sensors are spaced apart on the core package along a direction parallel to the axial direction of the pole post (222).

11. The overcurrent temperature rise testing system for battery cells according to any one of claims 8 to 10, characterized in that, The dimensions of the test bus (230) are the same as those of the matching bus (320) of the target cell (310) to be tested; And / or, The dimensions of the test core package (210) and the test cover assembly (220) are the same as those of the target cell (310) to be tested.

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