Battery cell shunt test method, device, system, computer equipment and storage medium

Abstract

The present application relates to a method, device, system, computer equipment and storage medium for current shunting test of battery cells. Parallel samples to be tested are used to simulate the multi-JR parallel structure in the battery cells to be tested. First, the test conditions required for the current shunting test of the battery cells to be tested are obtained. Under different test conditions, the test temperature is configured for each of the parallel samples to be tested of the battery cells to be tested. Then, the sample to be tested is subjected to charge and discharge test, and the operating electrical parameters of the branch where each sample to be tested is located in the parallel samples to be tested under the charge and discharge state are obtained. Finally, the current shunting test result of the battery cell to be tested is obtained by analyzing the operating electrical parameters, that is, the identification result of whether the battery cell to be tested has the risk of lithium deposition and / or whether there is an ultra-window risk. Through this scheme, the current shunting test of the battery cells of multiple parallel JR structure types can be realized, and the risk points and failure points caused by uneven current shunting inside the battery cells can be identified, so as to facilitate the subsequent targeted optimization design.

Description

Technical Field

[0001] The present application relates to the technical field of reliability testing, and in particular to a method, device, system, computer equipment, storage medium and computer program product for testing battery cell shunts. Background Art

[0002] With the development of science and technology, the types and application scenarios of batteries are becoming more and more extensive, bringing great convenience to people's daily production and life. Multi-JR (Jelly Roll, single roll core) parallel cells refer to cells formed by at least two JR structures in parallel. Due to the parallel JR structure inside the cell, it is easy to cause uneven current distribution in the cell, which seriously affects the normal use of electrical equipment.

[0003] Therefore, there is an urgent need to provide a solution for shunt testing of multiple JR parallel cells. Summary of the invention

[0004] Based on this, it is necessary to provide a battery cell shunt test method, device, system, computer equipment, storage medium and computer program product to perform shunt test on multiple JR parallel battery cells.

[0005] In a first aspect, the present application provides a battery cell shunt test method, comprising: obtaining the test conditions required for a shunt test on a battery cell to be tested; the test conditions characterize the test temperature of each sample to be tested in the parallel samples to be tested of the battery cell to be tested; the parallel samples to be tested are used to simulate a multi-JR parallel structure; when the parallel samples to be tested are in different test conditions, obtaining the operating electrical parameters of the branch where each sample to be tested in the parallel samples to be tested is located in a charge and discharge state; determining the shunt test result of the battery cell to be tested based on the operating electrical parameters; the shunt test result includes a lithium plating risk identification result and / or an ultra-window risk identification result.

[0006] The above-mentioned battery cell shunt test method uses parallel samples to simulate the multi-JR parallel structure in the battery cell to be tested. During the test process, the test conditions required for the shunt test of the battery cell to be tested are first obtained. Under different test conditions, the test temperature is configured for each sample to be tested in the parallel samples to be tested of the battery cell to be tested. Then, the charge and discharge test is performed on the sample to be tested to obtain the operating electrical parameters of the branch where each sample to be tested in the parallel samples to be tested is located under the charge and discharge state. Finally, the shunt test result of the battery cell to be tested is obtained by analyzing the operating electrical parameters, that is, the identification result of whether the battery cell to be tested has the risk of lithium deposition and / or whether there is an over-window risk. Through this scheme, the shunt test of the battery cell of the multi-parallel JR structure type can be realized, and the risk points and failure points caused by uneven shunt inside the battery cell can be identified, so as to facilitate the subsequent targeted optimization design.

[0007] In some embodiments, the parallel samples to be tested include parallel stacks, and when the parallel samples to be tested are in different test conditions, the operating electrical parameters of the branches in which each of the parallel samples to be tested is located in the charge and discharge state are obtained, including: when the parallel stacks are in different test conditions, the anode potential of each stack in the parallel stacks in the charge and discharge state is obtained; the anode potential is used for lithium plating risk identification.

[0008] The above scheme uses parallel stacking to simulate the internal resistance parallel structure of the battery cell to be tested, and combines the anode potential of each stacking in the parallel stacking under the charge and discharge state to identify the lithium plating risk caused by uneven current distribution of the battery cell to be tested, which has a high accuracy in identifying the lithium plating risk.

[0009] In some embodiments, when the parallel stack is in different test conditions, the anode potential of each stack in the parallel stack in the charge and discharge state is obtained, including: when the test cell completes the test detection, thermally balancing the test cell according to a preset thermal balance temperature; when the thermal balance treatment is completed, discharging the test cell to a preset lower limit cut-off voltage; configuring a corresponding test temperature for each stack in the parallel stack according to the test condition; charging the test cell with a preset charging strategy, and monitoring the anode potential of each stack in the parallel stack in real time; when the test cell is charged to a preset upper limit cut-off voltage, returning to the step of thermally balancing the test cell according to the preset thermal balance temperature until all test conditions are completed.

[0010] The above scheme configures corresponding test temperatures for each stack in the parallel stack according to different working conditions, so as to obtain the anode potential of each stack to identify the risk of lithium plating, which has high test reliability.

[0011] In some embodiments, determining the shunt test result of the battery cell to be tested according to the operating electrical parameter includes: when the anode potential is less than zero, determining that the battery cell to be tested has a risk of lithium deposition.

[0012] The above scheme, when detecting that the anode potential of each stack in the parallel stack is less than zero, determines that the battery cell to be tested has the risk of lithium plating, has high recognition accuracy.

[0013] In some embodiments, the parallel samples to be tested include parallel hard shells, and when the parallel samples to be tested are in different test conditions, the operating electrical parameters of the branches in which each of the samples to be tested is located in the parallel samples under the charge and discharge state are obtained, including: when the parallel hard shells are in different test conditions, the branch currents of the branches in which each hard shell in the parallel hard shell is located in the charge and discharge state are obtained; the branch currents are used for super window risk identification.

[0014] The above scheme uses parallel hard shells to simulate the internal resistance parallel structure of the battery cell to be tested, and combines the branch currents of the branches where each hard shell in the parallel hard shell is located in the charging and discharging state to identify the super-window risk caused by uneven current distribution of the battery cell to be tested, which has a high super-window risk identification accuracy.

[0015] In some embodiments, when the parallel hard shells are in different test conditions, the branch current of the branch where each hard shell in the parallel hard shells is located in the charge and discharge state is obtained, including: when the battery cell to be tested completes the test detection, the battery cell to be tested is thermally balanced according to a preset thermal balance temperature; when the thermal balance treatment is completed, the battery cell to be tested is discharged to a preset lower limit cut-off voltage; according to the test conditions, each hard shell in the parallel hard shell is respectively configured with a corresponding test temperature; the battery cell to be tested is charged with a preset charging strategy, and the branch current of the branch where each hard shell in the parallel hard shell is located is monitored in real time; when the battery cell to be tested is charged to a preset upper limit cut-off voltage, the step of thermally balancing the battery cell to be tested according to the preset thermal balance temperature is returned until all test conditions are completed.

[0016] The above scheme configures corresponding test temperatures for each hard shell in the parallel hard shell according to different working conditions, so as to obtain the branch current of the branch where each hard shell is located to perform super-window risk identification, which has high test reliability.

[0017] In some embodiments, determining the shunt test result of the battery cell to be tested based on the operating electrical parameters includes: in the case where the branch current exceeds a preset current window, determining that the battery cell to be tested has an out-of-window risk.

[0018] The above scheme, when detecting that a branch current exceeds a preset current window, determines that the battery cell to be tested has an out-of-window risk, has high recognition accuracy.

[0019] In some embodiments, the test of the battery cell to be tested includes at least one of a qualified sample appearance test, a qualified parameter sampling function test, a qualified sample resistance consistency test, and a completed test bench construction.

[0020] The above scheme starts lithium plating risk identification or super-window risk identification when at least one of the sample appearance inspection, parameter sampling function inspection, sample resistance consistency inspection and test bench construction of the battery cell to be tested is qualified, so as to further improve the test reliability of the battery cell shunt test.

[0021] In some embodiments, the test conditions required for the shunt test of the battery cell to be tested are obtained, including: when the test preparation is completed, activating the battery cell to be tested; when the activation of the battery cell to be tested is completed, discharging the battery cell to be tested to a preset lower limit cut-off voltage, and performing thermal balance treatment on the battery cell to be tested at a set thermal balance temperature; when the thermal balance treatment is completed, charging and discharging the battery cell to be tested, and obtaining the battery cell temperature at different positions of the battery cell to be tested during the charging and discharging process; the battery cell temperature is collected by temperature sensing lines set at different positions of the battery cell to be tested; determining the maximum temperature difference and the two battery cell temperatures corresponding to the maximum temperature difference according to the battery cell temperature; taking the two battery cell temperatures corresponding to the maximum temperature difference as a test condition; changing the set thermal balance temperature, and returning to the step of performing thermal balance treatment on the battery cell to be tested at the set thermal balance temperature until all the set thermal balance temperatures are tested.

[0022] In the above scheme, after the activation treatment of the battery cell to be tested is completed, the battery cell to be tested is subjected to thermal balance treatment at different set temperatures, and after the thermal balance treatment is completed, the accurate test conditions are analyzed based on the actual battery cell temperature of the battery cell to be tested during the charging and discharging process. In this way, the result of the actual temperature difference identification inside the product is used as the test condition, which can effectively improve the test accuracy of the shunt test.

[0023] In some embodiments, the activation treatment of the battery cell to be tested includes: discharging the battery cell to be tested to a preset lower limit cut-off voltage; performing thermal balance treatment on the battery cell to be tested at a preset thermal balance temperature; when the thermal balance treatment is completed, charging the battery cell to be tested to a preset upper limit cut-off voltage and letting it stand; when the standing time reaches a first preset time, charging the battery cell to be tested to a preset upper limit cut-off voltage and letting it stand again; when the standing time reaches a second preset time, accumulating the number of cycles once; when the number of cycles does not reach the preset number, returning to the step of discharging the battery cell to be tested to the preset lower limit cut-off voltage; the preset number of times is greater than or equal to one; when the number of cycles reaches the preset number, determining that the activation of the battery cell to be tested is completed.

[0024] The above scheme effectively improves the activation success rate of the battery cell through a preset number of charge and discharge and static treatment.

[0025] In some embodiments, the charging and discharging of the battery cell to be tested includes: charging the battery cell to be tested to a preset upper limit cut-off voltage according to a preset charging strategy; performing thermal balance treatment on the battery cell to be tested according to a preset thermal balance temperature; and when the thermal balance treatment is completed, discharging the battery cell to be tested to a preset lower limit cut-off voltage.

[0026] In the above scheme, when obtaining the test conditions for the battery cell to be tested, it is necessary to charge and discharge the battery cell to be tested to a preset upper limit cut-off voltage and a preset lower limit cut-off voltage. In this way, the battery cell temperature when the battery cell to be tested is at different charging voltages and discharging voltages can be simulated, thereby improving the accuracy of the battery cell temperature.

[0027] In the second aspect, the present application provides a battery cell shunt test device, including: a test condition acquisition module, used to obtain the test conditions required for the battery cell to be tested for shunt testing; the test conditions characterize the test temperature of each sample to be tested in the parallel samples to be tested of the battery cell to be tested; the parallel samples to be tested are used to simulate a multi-JR parallel structure; a test module, used to obtain the operating electrical parameters of the branch where each sample to be tested in the parallel samples to be tested is located in the charge and discharge state when the parallel samples to be tested are in different test conditions; a test result analysis module, used to determine the shunt test result of the battery cell to be tested based on the operating electrical parameters; the shunt test result includes a lithium plating risk identification result and / or an ultra-window risk identification result.

[0028] In a third aspect, the present application provides a battery cell shunt test system, comprising a temperature control device, a charge and discharge device, an electrical parameter acquisition device and a control device, wherein the temperature control device, the charge and discharge device and the electrical parameter acquisition device are respectively connected to the control device, the temperature control device is used to place the battery cell to be tested and provide different test conditions for the battery cell to be tested, and the control device is used to execute the steps of the above-mentioned battery cell shunt test method.

[0029] In a fourth aspect, the present application provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above-mentioned battery cell shunt test method when executing the computer program.

[0030] In a fifth aspect, 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 steps of the above-mentioned battery cell shunt test method are implemented.

[0031] In a sixth aspect, the present application provides a computer program product, including a computer program, which implements the steps of the above-mentioned battery cell shunt test method when executed by a processor. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0033] Figure 1 This is a flow chart of a cell current shunting test method in one embodiment of the present application;

[0034] Figure 2 This is a flow chart of a cell current shunting test method in another embodiment of the present application;

[0035] Figure 3 This is a schematic diagram of a parallel stacking simulation test process in one embodiment of the present application;

[0036] Figure 4 This is a flow chart of a cell current shunting test method in another embodiment of the present application;

[0037] Figure 5 This is a flow chart of a cell current shunting test method in yet another embodiment of the present application;

[0038] Figure 6 This is a schematic diagram of the parallel hard shell simulation test process in one embodiment of the present application;

[0039] Figure 7 This is a flow chart of a cell current shunting test method in another embodiment of the present application;

[0040] Figure 8 This is a schematic diagram of the test condition analysis process in one embodiment of the present application;

[0041] Fig. 9 This is a schematic diagram of the activation process of the battery cell to be tested in one embodiment of the present application;

[0042] Fig.10 This is a schematic diagram of the charging and discharging process of the battery cell to be tested in one embodiment of the present application;

[0043] Fig.11 This is a structural schematic diagram of a battery cell current shunting test device in one embodiment of the present application;

[0044] Fig.12 Schematic diagram of the internal structure of a computer device in one embodiment of the present application. DETAILED DESCRIPTION

[0045] The following embodiments of the technical solution of the present application will be described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0047] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0048] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0049] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0050] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0051] At present, from the perspective of market development, the application of power batteries is becoming more and more extensive. Power batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric cars, as well as military equipment and aerospace and other fields. With the continuous expansion of the application field of power batteries, the market demand is also constantly expanding.

[0052] With the rapid development of the electric vehicle industry and the increase in the number of electric vehicle users, users have a growing demand for charging speed and convenience. Fast charging technology can significantly shorten the charging time, improve the efficiency of vehicle use, and meet users' needs for fast energy replenishment during long-distance travel or in emergencies. Fast charging technology is often equipped with a water-cooled structure, which can easily lead to a large internal temperature difference.

[0053] Through research, it is found that there is a large temperature difference in the battery cell during the charging and discharging process (especially fast charging). Different temperatures will cause a large difference in the distribution of DCR (Direct Current Resistance) inside the battery cell, which will lead to uneven current distribution. In other words, uneven current distribution in the battery cell is often caused by the large temperature difference inside the battery cell. In addition, due to uneven current distribution, lithium deposition or super window phenomenon will further occur in the battery cell.

[0054] In order to alleviate the problem of uneven current distribution in battery cells, it is necessary to conduct uneven current distribution tests on battery cells, so as to fully identify the risk points and failure points caused by uneven current distribution in battery cells. In this way, the weak points caused by uneven current distribution in different product types can be found in a targeted manner, and targeted optimization designs can be carried out to improve the operating reliability of battery cell products.

[0055] Based on the above considerations, the present application provides a battery cell shunt test solution, which uses parallel samples to simulate the multi-JR parallel structure in the battery cell to be tested. During the test process, the test conditions required for the battery cell to be tested to perform a shunt test are first obtained, and under different test conditions, the test temperature is configured for each sample to be tested in the parallel samples to be tested of the battery cell to be tested. Then, a charge and discharge test is performed on the sample to be tested to obtain the operating electrical parameters of the branch where each sample to be tested in the parallel samples to be tested is located under the charge and discharge state. Finally, the shunt test result of the battery cell to be tested is obtained by analyzing the operating electrical parameters, that is, the identification result of whether the battery cell to be tested has a lithium plating risk and / or whether it has an ultra-window risk.

[0056] Through the above scheme, the shunt test of multiple parallel JR structure type battery cells can be realized, and the risk points and failure points caused by uneven shunt inside the battery cells can be identified, so as to facilitate subsequent targeted optimization design.

[0057] The battery cell shunt test method provided in the embodiment of the present application is applied to a battery cell having a parallel structure inside the battery cell. Specifically, the parallel structure can be a JR structure or other structures, which are not limited here. In order to facilitate understanding of the technical solution of the present application, the following embodiments are explained by taking a battery cell of a multi-JR parallel structure type as an example.

[0058] It should be pointed out that in the same battery cell, the number of parallel JR structures is not unique, and can be two or more, and there is no specific limitation. It is only necessary to use the sample to be tested to simulate the corresponding JR structure during the test process, and provide test temperatures for different samples to be tested under the test conditions to simulate the actual temperature difference of the battery cell to be tested. In order to facilitate the understanding of the technical solution of the present application, the following embodiments can be understood as a multi-JR parallel structure including two parallel JR structures.

[0059] See also Figure 1 The present application provides a battery cell shunt testing method, comprising step 102 , step 104 and step 106 .

[0060] Step 102, obtaining the test conditions required for the current shunt test of the battery cell to be tested.

[0061] Specifically, the test condition characterizes the test temperature of each of the parallel test samples of the test cell; the parallel test samples are used to simulate multiple JR parallel structures. The test cell is also a multiple parallel JR cell waiting to be tested. The shunt test is to test whether the test cell will have uneven shunting under different test conditions. The parallel test samples are the structure formed by connecting multiple test samples in parallel, and each test sample simulates a JR structure.

[0062] The battery cell shunt test method of the embodiment of the present application is implemented by a battery cell shunt test system, and is specifically executed by a control device of the battery cell shunt test system, which may be a working condition machine, a personal computer, etc., and is not specifically limited.

[0063] It should be pointed out that the control device is not the only one in which to obtain the test conditions. In one embodiment, the control device may pre-store all the test conditions required for different types of cells to be tested. When performing the shunt test, the control device only needs to obtain the type of the cell to be tested (either by scanning with a scanning device or by manual input by the user), and then match the type of the cell to be tested to obtain the corresponding test condition. This method has a high test condition acquisition efficiency and greatly improves the shunt test speed.

[0064] In another embodiment, in order to improve the accuracy of the test conditions, it is also possible to perform a charge and discharge test on the battery cell to be tested before each battery cell shunt test, and determine the various test conditions actually required in combination with the battery cell temperature during the charge and discharge process. In actual scenarios, there is no single way to obtain the test conditions, and you can choose according to actual needs.

[0065] Step 104 , when the parallel-connected samples to be tested are in different test conditions, obtain the operating electrical parameters of the branch where each of the parallel-connected samples to be tested is located in the charge and discharge state.

[0066] Specifically, the charge and discharge state is the operating state of charging or discharging the cell to be tested after the multi-parallel JR structure in the cell to be tested is replaced with the parallel sample to be tested. The branch where each sample to be tested is located is the parallel branch where the sample to be tested is located. The operating electrical parameters are the electrical parameters obtained by monitoring the operating state of the sample to be tested during the charge and discharge process, including but not limited to current parameters and voltage parameters.

[0067] It can be understood that in one embodiment, the battery cell shunt test system includes a temperature control device, a charge and discharge device, an electrical parameter acquisition device and a control device. When the test is performed, the battery cell to be tested is moved to the temperature control device. Under the action of the control device, the temperature control device can provide a test temperature for each of the parallel samples to be tested of the battery cell to be tested, that is, the battery cell to be tested enters different test conditions. The battery cell to be tested is charged and discharged by the charge and discharge device, and the electrical parameter acquisition device collects the operating electrical parameters of the branch where the sample to be tested is located during the charge and discharge process, and sends the operating electrical parameters to the control device. After the control device analyzes, the final shunt test result is obtained.

[0068] Step 106, determining the shunt test result of the battery cell to be tested according to the operating electrical parameters.

[0069] Specifically, the shunt test results include lithium plating risk identification results and / or super-window risk identification results. Cell lithium plating refers to the abnormal phenomenon that during the charging process of lithium-ion batteries, lithium ions fail to embed normally into the negative electrode material on the negative electrode side, but are deposited on the negative electrode surface in the form of metallic lithium. Lithium plating risk refers to the risk of lithium plating in the cell to be tested. Super-window means that the cell current exceeds the set, normal operating current range; super-window risk refers to the risk that the current of the cell to be tested exceeds the set operating current range.

[0070] The battery cell to be tested may have uneven current distribution due to the large internal temperature difference, and the uneven current distribution may further cause lithium deposition and / or super-window phenomenon in the battery cell to be tested. Therefore, the solution of this embodiment is to analyze whether the battery cell to be tested has the risk of lithium deposition and / or super-window risk by running electrical parameters to determine whether the battery cell to be tested has uneven current distribution under different test conditions.

[0071] Specifically, when the control device detects that the battery cell to be tested has a risk of lithium plating, it is determined that uneven current distribution occurs in the battery cell to be tested; and / or, when the control device detects that the battery cell to be tested has a risk of exceeding the window, it is determined that uneven current distribution occurs in the battery cell.

[0072] The above-mentioned battery cell shunt test method uses parallel samples to simulate the multi-JR parallel structure in the battery cell to be tested. During the test process, the test conditions required for the shunt test of the battery cell to be tested are first obtained. Under different test conditions, the test temperature is configured for each sample to be tested in the parallel samples to be tested of the battery cell to be tested. Then, the charge and discharge test is performed on the sample to be tested to obtain the operating electrical parameters of the branch where each sample to be tested in the parallel samples to be tested is located under the charge and discharge state. Finally, the shunt test result of the battery cell to be tested is obtained by analyzing the operating electrical parameters, that is, the identification result of whether the battery cell to be tested has the risk of lithium deposition and / or whether there is an over-window risk. Through this scheme, the shunt test of the battery cell of the multi-parallel JR structure type can be realized, and the risk points and failure points caused by uneven shunt inside the battery cell can be identified, so as to facilitate the subsequent targeted optimization design.

[0073] See also Figure 2 In some embodiments, connecting the samples to be tested in parallel includes connecting stacks in parallel, and step 104 includes step 202 .

[0074] Step 202, when the parallel stacks are in different test conditions, obtaining the anode potential of each stack in the parallel stack in a charge and discharge state.

[0075] Specifically, the anode potential is used to identify the risk of lithium plating. A parallel stack is a structure formed by connecting multiple stacks in parallel. It can be two stacks in parallel or a greater number of stacks in parallel. There is no specific limitation and it will vary depending on the type of battery cell to be tested. A stack is a structure formed by alternating positive and negative electrode sheets and diaphragms; the anode potential is the electrode potential formed by the anode (positive electrode) material in the electrolyte.

[0076] It should be pointed out that there is not only one way to obtain the anode potential. In one embodiment, the electrical parameter acquisition device includes a potential collector, which is connected to the control device. After the multi-parallel JR structure in the battery cell to be tested is replaced with a parallel stack, the parallel stack is used to simulate the parallel structure of the battery cell internal resistance of the battery cell to be tested. Different test temperatures are configured for different stacks of the parallel stack to simulate the actual temperature difference inside the product. When the battery cell to be tested is charged and discharged, the anode potential of each stack is obtained in real time and transmitted to the control device as the operating electrical parameter of the branch where the sample to be tested is located.

[0077] The above scheme uses parallel stacking to simulate the internal resistance parallel structure of the battery cell to be tested, and combines the anode potential of each stacking in the parallel stacking under the charge and discharge state to identify the lithium plating risk caused by uneven current distribution of the battery cell to be tested, which has a high accuracy in identifying the lithium plating risk.

[0078] See also Figure 3 In some embodiments, step 202 includes step 301 , step 302 , step 303 and step 304 .

[0079] Step 301 , when the battery cell to be tested has completed the test, thermal balance processing is performed on the battery cell to be tested according to a preset thermal balance temperature.

[0080] Step 302 : When the thermal balance process is completed, the battery cell to be tested is discharged to a preset lower limit cut-off voltage.

[0081] Step 303: configure a corresponding test temperature for each laminate in the parallel laminate according to the test conditions.

[0082] Step 304 , charging the battery cell to be tested according to a preset charging strategy, and monitoring the anode potential of each stack in the parallel stack in real time.

[0083] When the battery cell to be tested is charged to the preset upper limit cut-off voltage, the process returns to the step of performing thermal balance processing on the battery cell to be tested according to the preset thermal balance temperature until all test conditions are completed.

[0084] Specifically, the test inspection is the preparation work before the shunt test operation of the battery cell to be tested begins; the completion of the test inspection means that the preparation work is completed and the battery cell to be tested meets the test start conditions. The thermal balance treatment is the treatment of heat balance at various positions of the battery cell to be tested. The preset charging strategy is the preset strategy for charging the battery cell to be tested. The preset lower limit cut-off voltage is the preset minimum voltage allowed for the battery cell to be tested to discharge; the preset upper limit cut-off voltage is the preset maximum voltage allowed for the battery cell to be tested to charge. The preset thermal balance temperature is the preset temperature that the battery cell to be tested as a whole needs to reach before the shunt test is performed by charging and discharging.

[0085] It can be understood that, depending on the type of battery cell to be tested, there will be certain differences in the preset upper limit cut-off voltage, the preset lower limit cut-off voltage, and the required preset thermal equilibrium temperature, which are not specifically limited. For example, in one embodiment, the preset thermal equilibrium temperature can be set to 25 degrees Celsius (℃). Depending on the application scenario of the battery cell to be tested, the preset charging strategy will also be different. For example, if the battery cell to be tested is used in an electric vehicle, the corresponding preset charging strategy can be the whole vehicle charging strategy; further, if the electric vehicle has a fast charging function, the preset charging strategy can also be the whole vehicle fast charging strategy.

[0086] In actual scenarios, temperature collection points are configured at different positions on the surface of the battery cell to be tested. The control device can obtain the temperature collected by each temperature collection point and compare and analyze it with the preset thermal equilibrium temperature. When each temperature reaches the preset thermal equilibrium temperature, the thermal equilibrium process is considered to be completed. Or when the difference between each temperature and the preset thermal equilibrium temperature is less than the preset difference threshold, the thermal equilibrium process is considered to be completed.

[0087] After the thermal balance process is completed, the control device controls the charge and discharge device to start running and discharge the battery cell to be tested so that the voltage of the battery cell to be tested reaches the preset lower limit cut-off voltage. It should be pointed out that in this process, the discharge speed of the charge and discharge device for the battery cell to be tested is not unique and can be set to 0.33C (charge and discharge capacity ratio), etc., without specific limitation.

[0088] After the discharge of the battery cell to be tested reaches the preset lower limit cut-off voltage, the battery cell to be tested is moved (which can be achieved manually or by a mechanical handling device) to the temperature control device, and the temperature control device is used to configure the corresponding test temperature for each laminate in the parallel laminate. It should be pointed out that the structure of the temperature control device is not unique. In one embodiment, the temperature control device includes a temperature box and a heating plate, and the heating plate is arranged in the temperature box. Taking the parallel laminate including two laminates as an example, the battery cell to be tested can be placed in the temperature box, one of the laminates is directly placed in the temperature box, and the test temperature is provided for one of the laminates through the temperature box, and the other laminate is placed on the heating plate, and a higher test temperature is provided for the other laminate through the heating plate, thereby simulating the actual temperature difference of the battery cell to be tested. In other embodiments, if the number of laminates in the parallel laminate is greater than two, more heating plates can be used to provide different test temperatures for the laminates, and the specific details are no longer limited.

[0089] After the test temperature of the stack is set and the current required test conditions are simulated, the control device controls the charging and discharging device to start and charge the battery cell to be tested. At this time, the anode potential of each stack is monitored in real time through the potential detector and sent to the control device until the battery cell to be tested is finally charged to the preset upper limit cut-off voltage, completing the shunt test of the current condition. After that, the control device returns to perform thermal balance and discharge treatment on the battery cell to be tested again, and starts the test of the next test condition until all test conditions are completed.

[0090] It can be understood that after each test condition is completed, the battery cell to be tested can be taken out of the temperature control device for thermal balance and discharge, or can be thermally balanced and discharged in the temperature control device, without specific limitation.

[0091] The above scheme configures corresponding test temperatures for each stack in the parallel stack according to different working conditions, so as to obtain the anode potential of each stack to identify the risk of lithium plating, which has high test reliability.

[0092] See also Figure 4 , in some embodiments, step 106 includes step 402 .

[0093] Step 402: When the anode potential is less than zero, it is determined that the battery cell to be tested has a risk of lithium deposition.

[0094] Specifically, after obtaining the anode potential, the control device will analyze whether the anode potential is less than 0. If so, it means that the battery cell to be tested has a risk of lithium deposition; if not, it means that the battery cell to be tested does not have a risk of lithium deposition. Correspondingly, according to the test conditions corresponding to the anode potential less than 0, it can be known under which temperature difference conditions the battery cell to be tested has a risk of lithium deposition, that is, uneven current distribution occurs.

[0095] The above scheme, when detecting that the anode potential of each stack in the parallel stack is less than zero, determines that the battery cell to be tested has the risk of lithium plating, has high recognition accuracy.

[0096] See also Figure 5 In some embodiments, connecting the samples to be tested in parallel includes connecting hard shells in parallel, and step 104 includes step 502 .

[0097] Step 502, when the parallel hard shells are in different test conditions, the branch current of each branch where the hard shells in the parallel hard shells are located in the charge and discharge state is obtained.

[0098] Specifically, the branch current is used for super-window risk identification. The branch current is also the current value of the parallel branch where the hard shell is located. The hard shell refers to the protective packaging structure outside the battery cell. The scheme of this embodiment uses parallel hard shells to simulate the parallel JR structure, and provides different test temperatures for different hard shells, thereby simulating the temperature difference of the parallel structure of the internal resistance of the battery cell. When the battery cell to be tested is charged and discharged, the branch current of each branch is obtained in real time, and it is transmitted to the control device as the operating electrical parameter of the branch where the sample to be tested is located.

[0099] The above scheme uses parallel hard shells to simulate the internal resistance parallel structure of the battery cell to be tested, and combines the branch currents of the branches where each hard shell in the parallel hard shell is located in the charging and discharging state to identify the super-window risk caused by uneven current distribution of the battery cell to be tested, which has a high super-window risk identification accuracy.

[0100] See also Figure 6 In some embodiments, step 502 includes step 601 , step 602 , step 603 and step 604 .

[0101] Step 601 , when the battery cell to be tested has completed the test, thermal balance processing is performed on the battery cell to be tested according to a preset thermal balance temperature.

[0102] Step 602: When the thermal balance process is completed, the battery cell to be tested is discharged to a preset lower cut-off voltage.

[0103] Step 603, configuring a corresponding test temperature for each hard shell in the parallel hard shell according to the test conditions.

[0104] Step 604 , charging the battery cell to be tested according to a preset charging strategy, and monitoring the branch current of each branch where the hard shells in the parallel hard shells are located in real time.

[0105] When the battery cell to be tested is charged to the preset upper limit cut-off voltage, the process returns to the step of performing thermal balance processing on the battery cell to be tested according to the preset thermal balance temperature until all test conditions are completed.

[0106] Specifically, in this embodiment, when the parallel hard shell is used as the parallel test sample, the content of the test and detection of the battery cell to be tested is consistent with the detection content of the above-mentioned parallel stacking; the preset charging strategy, the preset lower limit cut-off voltage and the preset upper limit cut-off voltage are all consistent with the above-mentioned parallel stacking; the preset thermal equilibrium temperature can be consistent with the preset thermal equilibrium temperature of the above-mentioned parallel stacking, or it can be set differently, and the details will not be repeated.

[0107] Similarly, temperature collection points are arranged at different positions on the surface of the battery cell to be tested. The control device can obtain the temperature collected by each temperature collection point, and compare and analyze it with the preset thermal equilibrium temperature. When each temperature reaches the preset thermal equilibrium temperature, the thermal equilibrium processing is considered to be completed; or when the difference between each temperature and the preset thermal equilibrium temperature is less than the preset difference threshold, the thermal equilibrium processing is considered to be completed.

[0108] After the thermal balance process is completed, the control device controls the charging and discharging device to start running, and discharges the battery cell to be tested so that the voltage of the battery cell to be tested reaches the preset lower limit cut-off voltage. It can be understood that the discharge rate at this time can be consistent with the above-mentioned parallel stacking, or it can be set inconsistent, and there is no specific limitation.

[0109] After the discharge of the battery cell to be tested reaches the preset lower limit cut-off voltage, the battery cell to be tested is moved to the temperature control device, and the temperature control device is used to configure the corresponding test temperature for each hard shell in the parallel hard shell. It should be pointed out that the structure of the temperature control device is not unique. In one embodiment, the temperature control device includes a thermostat and a water bath, and the water bath is arranged in the thermostat. Taking the parallel hard shell including two hard shells as an example, the battery cell to be tested can be placed in the thermostat, one of the hard shells is directly placed in the thermostat, and the test temperature is provided for one of the hard shells through the thermostat, and the other laminate is placed in the water bath, and a higher test temperature is provided for the other laminate through the water bath, thereby simulating the actual temperature difference of the battery cell to be tested. In other embodiments, if the number of hard shells in the parallel hard shell is greater than two, more water baths can be used to provide different test temperatures for the hard shells, and the specifics are no longer limited.

[0110] After the test temperature of the hard shell is set and the current required test conditions are simulated, the control device controls the charging and discharging device to start and charge the battery cell to be tested. At this time, the branch current of each branch where the hard shell is located is monitored in real time through the electrical parameter detection device and sent to the control device until the battery cell to be tested is finally charged to the preset upper limit cut-off voltage, completing the shunt test of the current condition. After that, the control device returns to perform thermal balance and discharge processing on the battery cell to be tested again, and starts the test of the next test condition until all test conditions are completed.

[0111] The above scheme configures corresponding test temperatures for each hard shell in the parallel hard shell according to different working conditions, so as to obtain the branch current of the branch where each hard shell is located to perform super-window risk identification, which has high test reliability.

[0112] See also Figure 7 , in some embodiments, step 106 includes step 702 .

[0113] Step 702: When there is a branch current exceeding a preset current window, it is determined that there is a risk of exceeding the window for the battery cell to be tested.

[0114] Specifically, the preset current window is the preset current threshold range where the charging current is located under normal circumstances. After obtaining the branch current, the control device will analyze whether the branch current is not in the preset current window. If it is, it means that the battery cell to be tested is at risk of exceeding the window at this time; if it is not, it means that the battery cell to be tested does not have the risk of exceeding the window. Correspondingly, according to the test conditions corresponding to the branch current that is not in the preset current window, it can be known under which temperature difference conditions the battery cell to be tested is at risk of exceeding the window, that is, uneven current distribution occurs.

[0115] The above scheme, when detecting that a branch current exceeds a preset current window, determines that the battery cell to be tested has an out-of-window risk, has high recognition accuracy.

[0116] In some embodiments, the test of the battery cell to be tested includes at least one of a qualified sample appearance test, a qualified parameter sampling function test, a qualified sample resistance consistency test, and completion of the test bench construction.

[0117] In a more detailed embodiment, the test of the battery cell to be tested includes qualified sample appearance test, qualified parameter sampling function test, qualified sample resistance consistency test and test bench construction.

[0118] Before starting the test, you first need to perform an initial status test on the battery cell to be tested, check the sample appearance and labels, and take photos of the samples; check the sampling functions of voltage, pressure difference, temperature sensors, etc., that is, the detection parameter sampling function; check the ohmic internal resistance, connection internal resistance, line resistance, etc. of each sample to be tested in parallel to ensure that the status of the samples to be tested is consistent; build the test bench and take photos of the test bench.

[0119] The above scheme starts lithium plating risk identification or super-window risk identification when at least one of the sample appearance inspection, parameter sampling function inspection, sample resistance consistency inspection and test bench construction of the battery cell to be tested is qualified, so as to further improve the test reliability of the battery cell shunt test.

[0120] See also Figure 8 In some embodiments, step 102 includes step 801 , step 802 , step 803 , step 804 , step 805 and step 806 .

[0121] Step 801, when the test preparation is completed, the battery cell to be tested is activated.

[0122] Step 802 , when the activation of the battery cell to be tested is completed, the battery cell to be tested is discharged to a preset lower limit cut-off voltage, and a thermal balance process is performed on the battery cell to be tested at a set thermal balance temperature.

[0123] Step 803 , when the thermal balance process is completed, the battery cell to be tested is charged and discharged, and the battery cell temperature at different positions of the battery cell to be tested during the charging and discharging process is obtained.

[0124] Step 804 , determining the maximum temperature difference and the two battery cell temperatures corresponding to the maximum temperature difference according to the battery cell temperatures.

[0125] Step 805: taking the two battery cell temperatures corresponding to the maximum temperature difference as a test condition.

[0126] Step 806, changing the set thermal equilibrium temperature.

[0127] Return to the step of performing thermal balance processing on the battery cell to be tested at the set thermal balance temperature until all the set thermal balance temperatures have completed the test.

[0128] Specifically, the cell temperature is collected by temperature sensing wires set at different positions of the cell to be tested. A temperature sensing wire, also known as a temperature sensing wire or a temperature sensor wire, is a device for measuring temperature. Its working principle is mainly based on the change of material resistance with temperature.

[0129] The solution of this embodiment is to simulate the actual temperature difference inside the product, and a temperature sensing wire is built into the battery cell to be tested. Specifically, the temperature sensing wire can be arranged at least one of the contact surfaces of the parallel JR structures of the battery cell to be tested, the sides of each JR structure, the front of each JR structure, the bottom of each JR structure and the top surface (the side close to the positive and negative electrodes) of each JR structure. The number of temperature sensing wires arranged at each position can be one or more, and the temperature sensing wires can be arranged at equal intervals or irregularly. There is no specific limitation as long as the temperature change of the JR structure during charging and discharging of the battery cell to be tested can be reasonably characterized.

[0130] It should be noted that in actual scenarios, in order to obtain working conditions with different temperature differences, at least two temperature sensing lines need to be arranged in the parallel JR structure. In this case, the arrangement interval of the two temperature sensing lines can be set larger to obtain a suitable temperature difference. For example, one temperature sensing line can be arranged on the top surface of the JR structure, and the other temperature sensing line can be arranged on the bottom surface of the JR structure.

[0131] The set thermal equilibrium temperature is the equilibrium temperature that needs to be reached before the battery cell to be tested is charged when performing the test condition analysis. It can be understood that the size and number of the set thermal equilibrium temperatures are not unique and can be selected according to the actual scenario without specific limitation. For example, in one embodiment, the set thermal equilibrium temperature can be set to -10°C, 0°C, 25°C, 35°C, or 45°C.

[0132] Test preparation refers to the initial state detection of the battery cell to be tested, checking the appearance and label of the sample, taking pictures of the sample, setting up the test bench, checking whether the sampling function of the voltage and temperature sensors is normal, etc., which can be set up according to actual needs. Battery cell activation treatment is the process of fully activating the internal active substances and electrolyte of the battery cell to be tested through charge and discharge operations to achieve stable electrochemical performance.

[0133] After the test preparation is completed, the control device first activates the battery cell to be tested, and then discharges the voltage of the battery cell to be tested to a preset lower limit cut-off voltage. It can be understood that at this time, the battery cell to be tested is discharged at a set discharge rate, such as 0.33C. Then, the battery cell to be tested is subjected to thermal balance treatment by standing still or other methods, so that the battery cell to be tested reaches the set thermal balance temperature.

[0134] After that, the battery cell to be tested is charged and discharged, and during the charging and discharging process, the temperature data of different positions of the battery cell to be tested is obtained in real time according to the built-in temperature sensing line, and finally the maximum temperature difference and the two battery cell temperatures corresponding to the maximum temperature difference are determined based on the obtained temperature data, and the two battery cell temperatures are used as a set of test conditions. It can be understood that this embodiment takes two JR structure parallel battery cells as an example. In actual testing, the two temperatures of this set of test conditions can be used as the test temperatures of the two samples to be tested. In other embodiments, for other numbers of JR structure parallel type battery cells to be tested, several more sets of temperature difference data can be obtained, and the battery cell temperatures corresponding to the multiple sets of temperature difference data are used as test conditions, which will not be repeated here.

[0135] Whenever the control device completes the analysis of a test condition at a set thermal balance temperature, it will change the set thermal balance temperature and return to re-execute the operation of thermally balancing the battery cell to be tested at the set thermal balance temperature until all the set thermal balance temperatures are finally analyzed to the corresponding test conditions.

[0136] It should be noted that, in one embodiment, if the battery pack to be tested is equipped with a water cooling plate after being assembled into a battery pack, then when analyzing the test conditions, it is necessary to configure a water cooling plate for the battery pack to simulate the actual operating scenario.

[0137] In the above scheme, after the activation treatment of the battery cell to be tested is completed, the battery cell to be tested is subjected to thermal balance treatment at different set temperatures, and after the thermal balance treatment is completed, the accurate test conditions are analyzed based on the actual battery cell temperature of the battery cell to be tested during the charging and discharging process. In this way, the result of the actual temperature difference identification inside the product is used as the test condition, which can effectively improve the test accuracy of the shunt test.

[0138] See also Fig. 9 In some embodiments, the battery cell to be tested is activated, including step 901, step 902, step 903, step 904, step 905 and step 906.

[0139] Step 901, discharge the battery cell to be tested to a preset lower cut-off voltage.

[0140] Step 902 , performing thermal balance processing on the battery cell to be tested at a preset thermal balance temperature.

[0141] Step 903 , when the thermal balance process is completed, the battery cell to be tested is charged to a preset upper limit cut-off voltage and left to stand.

[0142] Step 904: When the resting time reaches the first preset time, the battery cell to be tested is charged again to the preset upper limit cut-off voltage and left to rest.

[0143] Step 905: when the static time reaches the second preset time, the number of cycles is accumulated once.

[0144] If the number of cycles does not reach the preset number, return to the step of discharging the battery cell to be tested to a preset lower cut-off voltage;

[0145] Step 906: When the number of cycles reaches a preset number, it is determined that the activation of the battery cell to be tested is completed.

[0146] Specifically, the preset number of times is greater than or equal to once. In the solution of this embodiment, the battery cell to be tested is activated by charging and discharging. First, the battery cell to be tested is discharged to a preset lower limit cut-off voltage. The discharge rate at this time can be set to 0.33C. After that, the battery cell to be tested is thermally balanced at a preset thermal equilibrium temperature (which can be set to 25°C). When it is detected that the temperature at each position of the battery cell to be tested reaches the preset thermal equilibrium temperature, it is determined that the thermal equilibrium treatment is completed. The control device controls the charging and discharging device to turn on, charges the battery cell to be tested to a preset upper limit cut-off voltage and leaves it to stand for a first preset time, and then charges the battery cell to be tested again to the preset upper limit cut-off voltage and leaves it to stand for a second preset time, completing an activation treatment.

[0147] It should be noted that in one activation process, the charging rates of the two charging of the battery cell to be tested are not the same, and the charging rate of the first charging is larger. The first preset time length is also different from the second preset time length, and the second preset time length should be greater than the first preset time length. For example, in a more detailed embodiment, the battery cell to be tested is charged to the upper limit cutoff voltage at 0.33C and left to stand for 5 minutes; then the battery cell to be tested is charged to the upper limit cutoff voltage at 0.05C and left to stand for 30 minutes.

[0148] In actual scenarios, the activation process can be performed twice or more times on the test cell according to the requirements, so that the test cell is completely in an activated state. In more detail, in one embodiment, the preset number of times can be set to two.

[0149] The above scheme effectively improves the activation success rate of the battery cell through a preset number of charge and discharge and static treatment.

[0150] See also Fig.10 In some embodiments, charging and discharging the battery cell to be tested includes step 1002 , step 1004 , and step 1006 .

[0151] Step 1002 , charging the battery cell to be tested to a preset upper limit cut-off voltage using a preset charging strategy.

[0152] Step 1004 , performing thermal balance processing on the battery cell to be tested according to a preset thermal balance temperature.

[0153] Step 1006 , when the thermal balance process is completed, discharge the battery cell to be tested to a preset lower limit cut-off voltage.

[0154] Specifically, after activation is completed, in the process of obtaining the test conditions through charging and discharging, it is necessary to charge the battery cell to be tested with a preset charging strategy, and then discharge the battery cell to be tested after thermal balance treatment. It can be understood that the preset charging strategy is consistent with the preset charging strategy in the above-mentioned parallel stacking or parallel hard shell test, and will not be repeated here. The preset thermal balance temperature, the preset upper limit cut-off voltage, and the preset lower limit cut-off voltage are all consistent with the relevant parameters in the above-mentioned parallel stacking or parallel hard shell test, and will not be repeated in detail.

[0155] In the above scheme, when obtaining the test conditions for the battery cell to be tested, it is necessary to charge and discharge the battery cell to be tested to a preset upper limit cut-off voltage and a preset lower limit cut-off voltage. In this way, the battery cell temperature when the battery cell to be tested is at different charging voltages and discharging voltages can be simulated, thereby improving the accuracy of the battery cell temperature.

[0156] In order to facilitate understanding of the technical solution of the present application, the present application is explained below in conjunction with more detailed embodiments.

[0157] First, temperature sensing wires are arranged at different positions of the parallel JR structure of the battery cell to be tested to collect the battery cell temperature. The number of temperature sensing wires can be set to 10.

[0158] Before acquiring the test conditions, perform initial status detection, check the sample appearance and labels, take photos of the samples, build the test bench, check whether the sampling functions of the voltage and temperature sensors are normal, and if the battery pack structure has a water cooling plate structure, the test bench is synchronously designed to use the water cooling plate for testing. After that:

[0159] (1) Discharge the cell to be tested at a current of 0.33C to the preset lower cut-off voltage;

[0160] (2) Thermal equilibrium at 25°C;

[0161] (3) Charge the cell to be tested to the upper cut-off voltage at a current of 0.33C and let it stand for 5 minutes; then charge the cell to be tested to the upper cut-off voltage at a current of 0.05C and let it stand for 30 minutes;

[0162] Repeat (1)-(3) twice to complete the activation of the battery cell to be tested;

[0163] (4) Discharge the cell to be tested at a current of 0.33C to the preset lower cut-off voltage;

[0164] (5) T (set thermal equilibrium temperature) thermal equilibrium; (T = -10℃, 0℃, 25℃, 35℃, 45℃)

[0165] (6) Charge the battery cell to be tested to the preset upper limit cut-off voltage using the vehicle fast charging strategy (preset charging strategy);

[0166] (7) Thermal equilibrium at 25°C;

[0167] (8) Discharge the cell to be tested to the preset lower cut-off voltage at 0.33C;

[0168] (9) During the charging and discharging process, the battery cell temperature is obtained in real time through the temperature sensing line, the maximum internal temperature difference and the corresponding two battery cell temperatures are analyzed, and the two battery cell temperatures are used as a set of test conditions;

[0169] Repeat steps (5) to (9) to complete all tests with set thermal equilibrium temperatures.

[0170] Secondly, parallel stacking was used as the experimental object to identify the risk of lithium plating:

[0171] Before the test begins, perform an initial status check, check the sample appearance and labels, and take photos of the samples; build the test bench; check the sampling functions of the voltage, differential pressure, and temperature sensors; check the ohmic internal resistance, connection internal resistance, and line resistance of the two stacks to ensure that the two samples are in the same state; take photos of the test bench;

[0172] (1) Thermal equilibrium at 25°C;

[0173] (2) Discharge the cell to be tested at 0.33C to the preset lower cut-off voltage;

[0174] (3) Setting the temperatures of the two stacks to two temperatures corresponding to the test conditions, wherein the temperature of the temperature box is set to a lower temperature and the stack with the heating plate is set to a higher temperature;

[0175] (4) Charging with the vehicle fast charging strategy, monitoring the anode potential of the two stacks until charging reaches the preset upper limit cut-off voltage;

[0176] Repeat (1)-(4) until all test conditions are tested;

[0177] Analyze whether there is a scenario where the anode potential of the two stacks is less than zero. If so, it indicates that there is a risk of lithium plating.

[0178] Finally, the parallel hard shell was used as the experimental object to identify the super window risk:

[0179] Before the test begins, perform an initial status test, check the sample appearance and labels, and take photos of the samples; build the test bench; check the sampling functions of the voltage, differential pressure, and temperature sensors; check the ohmic internal resistance, connection internal resistance, and line resistance of the two samples to ensure that the status of the two hard shells is consistent; take photos of the test bench; use an electrical parameter acquisition device (such as a current sensor) to monitor the current of each branch;

[0180] (1) Thermal equilibrium at 25°C;

[0181] (2) Discharge the cell to be tested at 0.33C to the preset lower cut-off voltage;

[0182] (3) The temperatures of the two hard shells are set to two temperatures corresponding to the test conditions, wherein the temperature of the incubator is set to a lower temperature and the temperature of the hard shell with the water bath is set to a higher temperature;

[0183] (4) Charging with the vehicle fast charging strategy, monitoring the branch current of the two branches until charging reaches the preset upper limit cut-off voltage;

[0184] Repeat (1)-(4) until all test conditions are tested;

[0185] The branch currents of the two branches are compared with the preset current window to determine the risk of exceeding the window due to the temperature difference factor; if there is a branch current exceeding the preset current window, it is determined that there is a risk of exceeding the window.

[0186] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0187] Based on the same inventive concept, the embodiment of the present application also provides a battery cell shunt test device for implementing the battery cell shunt test method involved above. The implementation solution provided by the device to solve the problem is similar to the implementation solution recorded in the above method, so the specific limitations in one or more battery cell shunt test device embodiments provided below can refer to the limitations of the battery cell shunt test method above, and will not be repeated here.

[0188] See also Fig.11 The present application provides a battery cell shunt testing device, including a test condition acquisition module 122, a test module 124 and a test result analysis module 126.

[0189] The test condition acquisition module 122 is used to obtain the test conditions required for the shunt test of the battery cell to be tested; the test module 124 is used to obtain the operating electrical parameters of the branch in which each sample to be tested is located in the parallel samples to be tested under the charge and discharge state when the parallel samples to be tested are in different test conditions; the test result analysis module 126 is used to determine the shunt test result of the battery cell to be tested based on the operating electrical parameters.

[0190] In some embodiments, the test module 124 is further used to obtain the anode potential of each stack in the parallel stack under the charge and discharge state when the parallel stack is in different test conditions.

[0191] In some embodiments, the test module 124 is also used to perform thermal balance treatment on the battery cell to be tested according to a preset thermal balance temperature when the test of the battery cell to be tested is completed; when the thermal balance treatment is completed, the battery cell to be tested is discharged to a preset lower limit cut-off voltage; according to the test conditions, a corresponding test temperature is configured for each stack in the parallel stack; the battery cell to be tested is charged according to a preset charging strategy, and the anode potential of each stack in the parallel stack is monitored in real time; when the battery cell to be tested is charged to the preset upper limit cut-off voltage, the operation of performing thermal balance treatment on the battery cell to be tested according to the preset thermal balance temperature is returned until all test conditions are completed.

[0192] In some embodiments, the test result analysis module 126 is further configured to determine that the battery cell to be tested has a risk of lithium deposition when the anode potential is less than zero.

[0193] In some embodiments, the test module 124 is further used to obtain the branch current of each branch of the parallel hard shells in the charge and discharge state when the parallel hard shells are in different test conditions.

[0194] In some embodiments, the test module 124 is also used to perform thermal balance treatment on the battery cell to be tested according to a preset thermal balance temperature when the test detection of the battery cell to be tested is completed; when the thermal balance treatment is completed, the battery cell to be tested is discharged to a preset lower limit cut-off voltage; according to the test conditions, a corresponding test temperature is configured for each hard shell in the parallel hard shell; the battery cell to be tested is charged according to a preset charging strategy, and the branch current of each branch in the parallel hard shell is monitored in real time; when the battery cell to be tested is charged to the preset upper limit cut-off voltage, the operation of performing thermal balance treatment on the battery cell to be tested according to the preset thermal balance temperature is returned until all test conditions are completed.

[0195] In some embodiments, the test result analysis module 126 is further configured to determine that the battery cell to be tested has an out-of-window risk when a branch current exceeds a preset current window.

[0196] In some embodiments, the test condition acquisition module 122 is also used to activate the battery cell to be tested when the test preparation is completed; when the activation of the battery cell to be tested is completed, the battery cell to be tested is discharged to a preset lower limit cut-off voltage, and the battery cell to be tested is thermally balanced at a set thermal balance temperature; when the thermal balance treatment is completed, the battery cell to be tested is charged and discharged, and the battery cell temperature at different positions of the battery cell to be tested during the charging and discharging process is obtained; the maximum temperature difference and the two battery cell temperatures corresponding to the maximum temperature difference are determined according to the battery cell temperature; the two battery cell temperatures corresponding to the maximum temperature difference are used as a test condition; the set thermal balance temperature is changed, and the operation of thermally balancing the battery cell to be tested at the set thermal balance temperature is returned to, until all the set thermal balance temperatures are tested.

[0197] In some embodiments, the test condition acquisition module 122 is also used to discharge the battery cell to be tested to a preset lower limit cut-off voltage; perform thermal balance treatment on the battery cell to be tested at a preset thermal balance temperature; when the thermal balance treatment is completed, charge the battery cell to be tested to a preset upper limit cut-off voltage and let it stand; when the standing time reaches a first preset time, charge the battery cell to be tested to the preset upper limit cut-off voltage again and let it stand; when the standing time reaches a second preset time, accumulate the number of cycles once; when the number of cycles does not reach the preset number, return to the operation of discharging the battery cell to be tested to the preset lower limit cut-off voltage; when the number of cycles reaches the preset number, determine that the activation of the battery cell to be tested is completed.

[0198] In some embodiments, the test condition acquisition module 122 is also used to charge the battery cell to be tested to a preset upper limit cut-off voltage using a preset charging strategy; perform thermal balance treatment on the battery cell to be tested according to a preset thermal balance temperature; and when the thermal balance treatment is completed, discharge the battery cell to be tested to a preset lower limit cut-off voltage.

[0199] Each module in the above-mentioned battery cell current shunting test device can be implemented in whole or in part by software, hardware and their combination. Each of the above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the corresponding operations of each of the above modules.

[0200] The above-mentioned battery cell shunt test device uses parallel samples to simulate the multi-JR parallel structure in the battery cell to be tested. During the test process, the test conditions required for the shunt test of the battery cell to be tested are first obtained. Under different test conditions, the test temperature is configured for each sample to be tested in the parallel samples to be tested of the battery cell to be tested. Then, the charge and discharge test is performed on the sample to be tested to obtain the operating electrical parameters of the branch where each sample to be tested in the parallel samples to be tested is located under the charge and discharge state. Finally, the shunt test result of the battery cell to be tested is obtained by analyzing the operating electrical parameters, that is, the identification result of whether the battery cell to be tested has the risk of lithium deposition and / or whether there is an over-window risk. Through this scheme, the shunt test of the battery cell of the multi-parallel JR structure type can be realized, and the risk points and failure points caused by uneven shunt inside the battery cell can be identified, so as to facilitate the subsequent targeted optimization design.

[0201] The present application provides a battery cell shunt test system, including a temperature control device, a charge and discharge device, an electrical parameter acquisition device and a control device. The temperature control device, the charge and discharge device and the electrical parameter acquisition device are respectively connected to the control device. The temperature control device is used to place the battery cell to be tested and provide different test conditions for the battery cell to be tested. The control device is used to execute the steps of the above-mentioned battery cell shunt test method.

[0202] Specifically, the implementation of the battery cell shunt test method is as shown in the above-mentioned embodiments, which will not be repeated here. The battery cell shunt test system uses parallel samples to simulate the multi-JR parallel structure in the battery cell to be tested. During the test process, the test conditions required for the battery cell to be tested to perform the shunt test are first obtained. Under different test conditions, the test temperature is configured for each sample to be tested in the parallel samples to be tested of the battery cell to be tested. Then, the sample to be tested is subjected to a charge and discharge test to obtain the operating electrical parameters of the branch where each sample to be tested is located in the parallel samples to be tested under the charge and discharge state. Finally, the shunt test result of the battery cell to be tested is obtained by analyzing the operating electrical parameters, that is, the identification result of whether the battery cell to be tested has a lithium deposition risk and / or whether there is an ultra-window risk. Through this scheme, the shunt test of the battery cell of the multi-parallel JR structure type can be realized, and the risk points and failure points caused by uneven shunt inside the battery cell can be identified, so as to facilitate the subsequent targeted optimization design.

[0203] In one embodiment, the temperature control device includes a temperature box and a heating plate arranged inside the temperature box, and the temperature box and the heating plate can be used to configure the test temperature for different stacks in the parallel stack. In another embodiment, the temperature control device also includes a water bath pot arranged inside the temperature box, and the temperature box and the water bath pot can be used to configure the test temperature for different hard shells in the parallel hard shell. The electrical parameter acquisition device includes a potentiometer and a current sensor, the potentiometer is used to collect the anode potential of the stack, and the current sensor is used to collect the branch current of the branch where the hard shell is located.

[0204] In an exemplary embodiment, a computer device is provided. The computer device may be a terminal, and its internal structure diagram may be as shown in FIG. Fig.12 As shown. The computer device includes a processor, a memory, an input / output interface, a communication interface, a display unit and an input device. The processor, the memory and the input / output interface are connected through a system bus, and the communication interface, the display unit and the input device are connected to the system bus through the input / output interface. 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 and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. 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 in a wired or wireless manner, and the wireless manner can be implemented through WIFI, a mobile cellular network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a battery cell shunt test method is implemented.

[0205] Those skilled in the art will understand that Fig.12 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.

[0206] In an exemplary embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and when the processor executes the computer program, the following steps are implemented:

[0207] Obtain the test conditions required for the shunt test of the battery cell to be tested; when the parallel samples to be tested are in different test conditions, obtain the operating electrical parameters of the branch where each sample to be tested is located in the parallel samples to be tested under the charge and discharge state; determine the shunt test results of the battery cell to be tested based on the operating electrical parameters.

[0208] In one embodiment, a computer readable storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the following steps are implemented:

[0209] Obtain the test conditions required for the shunt test of the battery cell to be tested; when the parallel samples to be tested are in different test conditions, obtain the operating electrical parameters of the branch where each sample to be tested is located in the parallel samples to be tested under the charge and discharge state; determine the shunt test results of the battery cell to be tested based on the operating electrical parameters.

[0210] In one embodiment, a computer program product is provided, comprising a computer program, which, when executed by a processor, implements the following steps:

[0211] Obtain the test conditions required for the shunt test of the battery cell to be tested; when the parallel samples to be tested are in different test conditions, obtain the operating electrical parameters of the branch where each sample to be tested is located in the parallel samples to be tested under the charge and discharge state; determine the shunt test results of the battery cell to be tested based on the operating electrical parameters.

[0212] 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. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. 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 are not limited to this.

[0213] The above-mentioned computer device, storage medium and computer program product use parallel samples to simulate the multi-JR parallel structure in the battery cell to be tested. During the test process, the test conditions required for the battery cell to be tested to perform a shunt test are first obtained. Under different test conditions, the test temperature is configured for each sample to be tested in the parallel samples to be tested of the battery cell to be tested. Then, the sample to be tested is subjected to a charge and discharge test to obtain the operating electrical parameters of the branch where each sample to be tested is located in the parallel samples to be tested under the charge and discharge state. Finally, the shunt test result of the battery cell to be tested is obtained by analyzing the operating electrical parameters, that is, the identification result of whether the battery cell to be tested has a lithium deposition risk and / or whether there is an ultra-window risk. Through this scheme, the shunt test of the battery cell of the multi-parallel JR structure type can be realized, and the risk points and failure points caused by uneven shunt inside the battery cell can be identified, so as to facilitate the subsequent targeted optimization design.

[0214] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery cell shunt test method, characterized in that: include: Obtain the test conditions required for the shunt test of the battery cell to be tested; The test condition represents the test temperature of each of the parallel-connected samples of the battery cell to be tested; The parallel test samples are used to simulate a multi-JR parallel structure; When the parallel-connected samples to be tested are in different test conditions, obtaining operating electrical parameters of the branch where each of the parallel-connected samples to be tested is located in the charge and discharge state; Determine the shunt test result of the battery cell to be tested according to the operating electrical parameters; the shunt test result includes a lithium plating risk identification result and / or an ultra-window risk identification result; The parallel samples to be tested include parallel stacks, and when the parallel samples to be tested are in different test conditions, the operating electrical parameters of the branches of each of the parallel samples to be tested in the charge and discharge state are obtained, including: when the parallel stacks are in different test conditions, the anode potential of each stack in the parallel stacks in the charge and discharge state is obtained; the anode potential is used for lithium plating risk identification; The parallel samples to be tested include parallel hard shells. When the parallel samples to be tested are in different test conditions, the operating electrical parameters of the branches in which each of the samples to be tested is located in the parallel samples under the charge and discharge state are obtained. The method also includes: when the parallel hard shells are in different test conditions, the branch currents of the branches in which each hard shell in the parallel hard shells is located in the charge and discharge state are obtained; the branch currents are used for super window risk identification.

2. The battery cell current shunting test method according to claim 1, characterized in that: The step of obtaining the anode potential of each laminate in the parallel laminate under the charge and discharge state when the parallel laminate is in different test conditions includes: When the battery cell to be tested has completed the test, thermally balancing the battery cell to be tested according to a preset thermal balance temperature; When the thermal balance process is completed, the battery cell to be tested is discharged to a preset lower limit cut-off voltage; According to the test conditions, each lamination in the parallel laminations is respectively configured with a corresponding test temperature; Charging the battery cell to be tested according to a preset charging strategy, and monitoring the anode potential of each stack in the parallel stack in real time; When the battery cell to be tested is charged to the preset upper limit cut-off voltage, the process returns to the step of performing thermal balance processing on the battery cell to be tested according to the preset thermal balance temperature until all test conditions are completed.

3. The battery cell shunt test method according to claim 1, characterized in that: Determining the shunt test result of the battery cell to be tested according to the operating electrical parameter includes: When the anode potential is less than zero, it is determined that the battery cell to be tested has a risk of lithium deposition.

4. The battery cell shunt test method according to claim 1, characterized in that: When the parallel hard shells are in different test conditions, obtaining the branch current of each hard shell in the parallel hard shells in the charge and discharge state includes: When the battery cell to be tested has completed the test, thermally balancing the battery cell to be tested according to a preset thermal balance temperature; When the thermal balance process is completed, the battery cell to be tested is discharged to a preset lower limit cut-off voltage; According to the test conditions, each hard shell in the parallel hard shell is respectively configured with a corresponding test temperature; The battery cell to be tested is charged according to a preset charging strategy, and the branch current of each branch where each hard shell in the parallel hard shell is located is monitored in real time; When the battery cell to be tested is charged to the preset upper limit cut-off voltage, the process returns to the step of performing thermal balance processing on the battery cell to be tested according to the preset thermal balance temperature until all test conditions are completed.

5. The battery cell current shunting test method according to claim 1, characterized in that: Determining the shunt test result of the battery cell to be tested according to the operating electrical parameter includes: In the case where the branch current exceeds the preset current window, it is determined that the battery cell to be tested has an out-of-window risk.

6. The battery cell current shunting test method according to claim 2 or 4, characterized in that: The test of the battery cell to be tested includes at least one of the following: qualified sample appearance test, qualified parameter sampling function test, qualified sample resistance consistency test and completed test bench construction.

7. The battery cell current shunting test method according to any one of claims 1 to 5, characterized in that: The test conditions required for obtaining the test cell for the shunt test include: When the test preparation is completed, activating the battery cell to be tested; When the activation of the battery cell to be tested is completed, the battery cell to be tested is discharged to a preset lower limit cut-off voltage, and a thermal balance treatment is performed on the battery cell to be tested at a set thermal balance temperature; When the thermal balance process is completed, the battery cell to be tested is charged and discharged, and the battery cell temperature at different positions of the battery cell to be tested during the charging and discharging process is obtained; the battery cell temperature is collected by temperature sensing wires set at different positions of the battery cell to be tested; Determine a maximum temperature difference according to the battery core temperature, and two battery core temperatures corresponding to the maximum temperature difference; Taking the two battery core temperatures corresponding to the maximum temperature difference as a test condition; The set thermal balance temperature is changed, and the process returns to the step of performing thermal balance processing on the battery cell to be tested at the set thermal balance temperature until all the set thermal balance temperatures have completed the test.

8. The battery cell current shunting test method according to claim 7, characterized in that: The step of activating the battery cell to be tested comprises: Discharging the battery cell to be tested to a preset lower cut-off voltage; Perform thermal balance processing on the battery cell to be tested at a preset thermal balance temperature; When the thermal balance treatment is completed, charging the battery cell to be tested to a preset upper limit cut-off voltage and leaving it to stand; When the resting time reaches the first preset time, charging the battery cell to be tested to a preset upper limit cut-off voltage and leaving it to rest again; When the static time reaches the second preset time, the number of cycles is accumulated once; When the number of cycles does not reach a preset number, returning to the step of discharging the battery cell to be tested to a preset lower limit cut-off voltage; the preset number of times is greater than or equal to one; When the number of cycles reaches a preset number, it is determined that the activation of the battery cell to be tested is completed.

9. The battery cell current shunting test method according to claim 7, characterized in that: The charging and discharging of the battery cell to be tested comprises: Charging the battery cell to be tested to a preset upper limit cut-off voltage using a preset charging strategy; Performing thermal balance processing on the battery cell to be tested according to a preset thermal balance temperature; When the thermal balance process is completed, the battery cell to be tested is discharged to a preset lower limit cut-off voltage.

10. A battery cell current shunting test device, characterized in that: include: A test condition acquisition module is used to obtain the test conditions required for the shunt test of the battery cell to be tested; The test condition represents the test temperature of each of the parallel-connected samples of the battery cell to be tested; the parallel-connected samples to be tested are used to simulate a multi-JR parallel structure; A testing module, used for obtaining the operating electrical parameters of the branch where each of the parallel-connected samples to be tested is located in the charging and discharging state when the parallel-connected samples to be tested are in different testing conditions; A test result analysis module, used to determine the shunt test result of the battery cell to be tested according to the operating electrical parameters; the shunt test result includes a lithium plating risk identification result and / or an ultra-window risk identification result; The parallel test sample includes parallel stacks, and the test module is further used to: obtain the anode potential of each stack in the parallel stack under the charge and discharge state when the parallel stack is in different test conditions; the anode potential is used for lithium plating risk identification; The parallel sample to be tested includes a parallel hard shell, and the test module is also used to: obtain the branch current of each branch in the parallel hard shell under the charge and discharge state when the parallel hard shell is in different test conditions; the branch current is used for super window risk identification.

11. A battery cell current shunting test system, characterized in that: It includes a temperature control device, a charge and discharge device, an electrical parameter acquisition device and a control device, wherein the temperature control device, the charge and discharge device and the electrical parameter acquisition device are respectively connected to the control device, the temperature control device is used to place the battery cell to be tested and provide different test conditions for the battery cell to be tested, and the control device is used to execute the steps of the battery cell shunt test method described in any one of claims 1 to 9.

12. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, the steps of the battery cell shunt testing method described in any one of claims 1 to 9 are implemented.

13. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the battery cell shunt testing method described in any one of claims 1 to 9 are implemented.

14. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the battery cell shunt testing method described in any one of claims 1 to 9 are implemented.

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