A battery pack life evaluation method, device and test equipment

Abstract

The application provides a battery pack life evaluation method and device and test equipment, and relates to the technical field of electric vehicles. The method comprises: performing cell life testing on a cell to obtain cell test data, wherein the cell life testing comprises cell cycle life testing and / or cell calendar life testing; performing cycle life testing on a battery unit to obtain unit test data, wherein the battery unit is used to simulate a part of cells in a to-be-evaluated battery pack CTP structure constructed by using at least one cell; and obtaining a life evaluation result of the to-be-evaluated battery pack according to the cell test data and the unit test data. The scheme of the application solves the problem that, in the prior art, the starting time of battery pack life evaluation is late, resulting in a long battery development cycle and high test cost.

Description

Technical Field

[0001] This invention relates to the field of electric vehicle technology, and in particular to a method, apparatus, and testing equipment for evaluating battery pack life. Background Technology

[0002] To achieve long driving range, high-energy-density lithium-ion batteries have become a key focus of development in the electric vehicle sector.

[0003] With the gradual increase in energy density, the Cell to Pack (CTP) structure has emerged. Since the CTP structure eliminates the concept of battery modules, the testing of CTP batteries is usually carried out directly after the cell testing is completed. However, due to the constraints of the development time of internal components during the battery pack development process, it is impossible to start cycle testing in advance, resulting in problems such as increased development cycle, increased testing costs, and deviations in simulation data. Summary of the Invention

[0004] This invention provides a method, apparatus, and testing equipment for evaluating battery pack lifespan, which addresses the problem that the timing of initiating battery pack lifespan evaluation in the prior art is too late, resulting in long battery development cycles and high testing costs.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] According to one aspect of the present invention, a method for evaluating battery pack life is provided, comprising:

[0007] Perform cell life tests on the battery cells and obtain cell test data, wherein the cell life tests include: cell cycle life tests and / or cell calendar life tests;

[0008] Cycle life tests are performed on the battery cells to obtain cell test data, wherein the battery cells are used to simulate a portion of the cell-to-pack CTP structure within the battery pack to be evaluated, constructed using at least one of the battery cells.

[0009] Based on the cell test data and the unit test data, the life assessment results of the battery pack to be evaluated are obtained.

[0010] Optionally, when the cell life test includes a cell cycle life test, the step of performing a cell life test on the cell and obtaining cell test data includes:

[0011] Under at least one test condition, the cell is subjected to a cell cycle life test, and the cell physical parameters before and after the cell cycle life test are recorded as the cell test data.

[0012] The test conditions include voltage conditions and / or temperature conditions.

[0013] Optionally, when the cell life test includes a cell calendar life test, the step of performing a cell life test on the cell and obtaining cell test data includes:

[0014] Under at least one temperature condition, the battery cell is subjected to a battery cell calendar life test, and the battery cell physical parameters before and after the battery cell calendar life test are recorded as the battery cell test data.

[0015] Optionally, the step of performing cycle life testing on the battery cells to obtain cell test data includes:

[0016] Under at least one preset operating condition, the battery cell is subjected to a cycle life test, and the cell physical parameters of the battery cell before and after the cycle life test are recorded as the cell test data.

[0017] The design parameters corresponding to the battery cell are consistent with those of the battery pack to be evaluated. The design parameters include at least one of liquid cooling parameters, environmental parameters, material parameters, and structural parameters.

[0018] Optionally, the physical parameters of the battery cell include at least one of the following: capacity, open-circuit voltage, internal resistance, and mass.

[0019] Optionally, obtaining the life assessment result of the battery pack to be evaluated based on the cell test data and the unit test data includes:

[0020] The battery cell test data is analyzed to determine whether the battery cell is qualified, and,

[0021] The unit test data is analyzed to determine whether the battery unit is qualified.

[0022] If both the battery cell and the battery unit are qualified, the life evaluation result of the battery pack to be evaluated is determined to be qualified.

[0023] According to another aspect of the present invention, a battery pack life assessment device is provided, comprising:

[0024] The first testing module is used to perform cell life testing on the battery cells and obtain cell test data. The cell life testing includes: cell cycle life testing and / or cell calendar life testing.

[0025] The second test module is used to perform cycle life tests on the battery cells and obtain cell test data. The battery cells are used to simulate a portion of the cell-to-pack CTP structure in the battery pack to be evaluated, which is constructed using at least one of the cells.

[0026] The data analysis module is used to obtain the life assessment results of the battery pack to be evaluated based on the cell test data and the unit test data.

[0027] According to another aspect of the present invention, a testing device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor; when the processor executes the computer program, it implements the cyclic testing method described above.

[0028] According to another aspect of the invention, a readable storage medium is provided having a program or instructions stored thereon, which, when executed by a processor, implement the steps in the loop test method described above.

[0029] The beneficial effects of this invention are:

[0030] The above-described scheme uses battery cells to simulate the cell-to-pack (CTP) structure within the battery pack under evaluation. By analyzing test data obtained from testing the cells and battery units, the lifespan assessment results of the battery pack under evaluation can be obtained. This allows for battery pack lifespan assessment during the R&D phase, eliminating the need to wait for battery pack production to complete cycle testing. This advances the start of battery pack lifespan assessment, effectively shortening the overall design verification cycle, improving cycle testing efficiency, and reducing testing costs. Attached Figure Description

[0031] Figure 1 This is a schematic diagram illustrating the battery pack life assessment method provided in an embodiment of the present invention.

[0032] Figure 2 This is a schematic diagram of the battery pack life assessment device provided in an embodiment of the present invention. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] This invention addresses the problem that the timing of initiating battery pack life assessment in the prior art is too late, resulting in long battery development cycles and high testing costs. It provides a battery pack life assessment method, apparatus, and testing equipment.

[0035] like Figure 1 As shown, one embodiment of the present invention provides a battery pack life assessment method, comprising:

[0036] Step 101: Perform a cell life test on the battery cell and obtain cell test data. The cell life test includes: cell cycle life test and / or cell calendar life test.

[0037] Step 102: Perform cycle life test on the battery cell and obtain cell test data, wherein the battery cell is used to simulate a portion of the cell-to-pack CTP structure in the battery pack to be evaluated constructed using at least one of the cells.

[0038] Step 103: Based on the cell test data and the unit test data, obtain the life assessment result of the battery pack to be evaluated.

[0039] It should be noted that in existing technologies, during CTP development, cycle testing is typically conducted after cell cycle life testing and cell calendar life testing, followed by battery pack cycle testing. However, this traditional testing method involves a significant verification gap between cell life testing and battery pack cycle life testing. This period is usually used for detailed battery pack design and component manufacturing, making it difficult to conduct battery pack life testing during this timeframe.

[0040] In this embodiment, a partial cell-to-pack (CTP) structure can be constructed within the battery pack to be evaluated, using battery cells to simulate battery cells. By analyzing test data obtained from testing the cells and battery units, the lifespan assessment results of the battery pack can be obtained. This allows for battery pack lifespan assessment during the R&D phase, eliminating the need to wait for battery pack production to complete cycle testing. This advances the start time for battery pack lifespan assessment, effectively shortening the overall design verification cycle of the battery pack, improving cycle testing efficiency, and reducing testing costs.

[0041] Optionally, when the cell life test includes a cell cycle life test, the step of performing a cell life test on the cell and obtaining cell test data includes:

[0042] Under at least one test condition, the battery cell is subjected to a battery cell cycle life test, and the battery cell physical parameters before and after the battery cell cycle life test are recorded as the battery cell test data; wherein, the test conditions include: voltage conditions and / or temperature conditions; the battery cell physical parameters may include at least one of the following: capacity, open circuit voltage, internal resistance, and mass.

[0043] Here, the test conditions can be set according to specific circumstances. For example, the voltage conditions can be the following voltage ranges: 2.75V~4.2V, 3.0V~4.15V, etc., and the temperature conditions can be 0℃, 25℃, 35℃, 45℃, etc.

[0044] In this embodiment, the purpose of conducting cell cycle life tests under different voltage and temperature conditions and recording the cell physical parameters before and after the cell cycle life tests is to analyze the changes in the cell physical parameters and determine whether the tested cell is qualified.

[0045] Optionally, when the cell life test includes a cell calendar life test, the step of performing a cell life test on the cell and obtaining cell test data includes:

[0046] Under at least one temperature condition, the cell is subjected to a cell calendar life test, and the cell physical parameters before and after the cell calendar life test are recorded as the cell test data. The cell physical parameters include at least one of the following: capacity, open circuit voltage, internal resistance, and mass.

[0047] Here, the temperature conditions can be set according to specific circumstances. For example, the temperature conditions can be 25℃, 35℃, 45℃, 60℃, etc.

[0048] In this embodiment, the purpose of conducting cell calendar life tests under different temperature conditions and recording the cell physical parameters before and after the cell calendar life tests is to analyze the changes in the cell physical parameters and determine whether the tested cell is qualified.

[0049] It's important to note that since cell-level cycle testing doesn't involve liquid cooling, and the environmental conditions around the cells differ from the actual battery pack design, assessing battery pack life solely based on cell test data is inaccurate. Here, battery cells can be used to simulate a portion of the CTP structure within the battery pack under evaluation, and cycle life testing can be performed on these cells (i.e., testing using a portion of the energy zone within the battery pack). The conditions around the cells in these cells are similar to those within a real battery pack, thus providing a more accurate battery pack life assessment. This allows for battery pack life assessment during the R&D phase, filling the technological gap in battery life assessment after the elimination of the module concept in CTP structures.

[0050] Optionally, the step of performing cycle life testing on the battery cells to obtain cell test data includes:

[0051] Under at least one preset operating condition, the battery cell is subjected to a cycle life test, and the cell physical parameters of the battery cell before and after the cycle life test are recorded as the cell test data; wherein, the design parameters corresponding to the battery cell are consistent with the battery pack to be evaluated, and the design parameters include at least one of liquid cooling parameters, environmental parameters, material parameters and structural parameters.

[0052] Here, information related to the physical parameters of the battery cells can also be recorded during the test. The purpose of keeping the design parameters of the battery cells consistent with those of the battery pack under evaluation (i.e., the normally designed battery pack structure) is to better simulate the real-world conditions of the battery pack under evaluation and obtain more accurate lifespan assessment results.

[0053] It should be noted that environmental parameters may include temperature, voltage, etc., as well as the initial force between the cells (e.g., 1000N), the relevant parameters of the thermally conductive structural adhesive between the bottom surface of the cell and the liquid cooling plate, the relevant parameters of the thermal insulation or thermally conductive materials added between the cells (e.g., foam, mica board), and the relevant parameters of the flow channel scheme inside the liquid cooling plate; material parameters may be parameters related to the materials used in the cells; structural parameters may include the spacing between the cells, etc.

[0054] It should also be noted that the preset operating conditions here generally correspond to the overall vehicle operating conditions. The preset operating conditions need to be converted into the corresponding operating conditions of the battery cells through the parameters of the battery pack. For example, if the current operating condition is used as the preset operating condition, no parameter adjustment is required; if the power operating condition is used as the preset operating condition, the corresponding parameters need to be calculated according to the voltage ratio between the battery pack and the battery cells.

[0055] In this embodiment, the purpose of performing a cycle life test on the battery cell under at least one preset operating condition and recording the cell physical parameters before and after the cycle life test is to analyze the changes in the cell physical parameters and determine whether the tested battery cell is qualified.

[0056] As an optional embodiment, in order to solve the problem that the battery pack life assessment is initiated too late in the prior art, thermal management design can be carried out in advance using some structural units and cells at the battery pack level to manufacture some units of CTP (i.e., the battery cells), and then cycle life tests can be performed on the battery cells to obtain the cycle life test results of the battery cells.

[0057] Thus, when performing cycle life testing on battery cells, a testing device of around 100V and an environmental chamber of 1 square meter are generally sufficient, eliminating the need for an environmental chamber and charge / discharge equipment at the battery pack level. This saves a significant amount of testing costs during the testing process. Compared to a complete battery pack, it also saves a large number of cells and internal components, reducing the cost of prototypes.

[0058] Optionally, the physical parameters of the battery cell include at least one of the following: capacity, open-circuit voltage, internal resistance, and mass.

[0059] Optionally, obtaining the life assessment result of the battery pack to be evaluated based on the cell test data and the unit test data includes:

[0060] The battery cell test data is analyzed to determine whether the battery cell is qualified, and the unit test data is analyzed to determine whether the battery unit is qualified; if both the battery cell and the battery unit are qualified, the life evaluation result of the battery pack to be evaluated is determined to be qualified.

[0061] In this embodiment, data analysis of cell test data and unit test data, as well as disassembly analysis of the cells, can determine whether the cell's cycle life meets its requirements, thereby determining whether the cell is qualified. If it is unqualified, it indicates that the design needs to be improved as soon as possible until the design requirements are met; if it is qualified, battery production can proceed according to the normal development schedule, and after the battery pack is assembled, the final battery pack life verification can be initiated. In this way, problems can be rectified in advance, shortening the battery development cycle.

[0062] By using the above-mentioned battery pack life assessment method and conducting cycle life tests on battery cells, the lifespan of CTP structure battery packs can be assessed in advance, providing a reliable evaluation basis for CTP structure battery packs.

[0063] It is worth mentioning that the test data (cell test data, unit test data, etc.) obtained in the above-mentioned battery pack life assessment process can be used to simulate battery pack test items. For example, the battery pack cycle test can simulate the cycle life result of the battery pack by using the test results of the cell life test. Then, the test results of the cycle life test of the battery unit can be used for correction to modify the life curve of the simulated battery pack, so that the simulated cycle life result tends to the true value and the test result is more accurate.

[0064] In this way, as the amount of test data increases, separate test databases for battery cells and conventional battery packs can be established. By comparing and analyzing the cycle life test results of battery cells and battery packs, the conversion relationship between battery cell and battery pack cycle life tests can be derived. Thus, in later stages, the cycle life test results of the battery pack can be calculated from the cycle life test results of the battery cells. In other words, with a sufficiently large amount of data accumulated, only battery cell cycle life testing needs to be performed during project development, gradually replacing battery pack cycle life testing. This saves on battery pack cycle life testing costs, shortens the testing cycle, and reduces battery production costs.

[0065] In this embodiment of the invention, a partial cell-to-pack (CTP) structure can be constructed within the battery pack to be evaluated using battery cells to simulate battery cells. By analyzing test data obtained from testing the cells and battery units, the lifespan assessment results of the battery pack to be evaluated can be obtained. This allows for battery pack lifespan assessment during the R&D phase, eliminating the need to wait for battery pack production to complete cycle testing. This advances the start time for battery pack lifespan assessment, effectively shortening the overall design verification cycle of the battery pack, improving cycle testing efficiency, and reducing testing costs.

[0066] like Figure 2 As shown, this embodiment of the invention also provides a battery pack life assessment device, comprising:

[0067] The first test module 21 is used to perform cell life test on the battery cell and obtain cell test data. The cell life test includes: cell cycle life test and / or cell calendar life test.

[0068] The second test module 22 is used to perform cycle life tests on the battery cells and obtain cell test data. The battery cells are used to simulate a portion of the cell-to-pack CTP structure in the battery pack to be evaluated, which is constructed using at least one of the cells.

[0069] The data analysis module 23 is used to obtain the life evaluation result of the battery pack to be evaluated based on the cell test data and the unit test data.

[0070] In this embodiment, a partial cell-to-pack (CTP) structure can be constructed within the battery pack to be evaluated, using battery cells to simulate battery cells. By analyzing test data obtained from testing the cells and battery units, the lifespan assessment results of the battery pack can be obtained. This allows for battery pack lifespan assessment during the R&D phase, eliminating the need to wait for battery pack production to complete cycle testing. This advances the start time for battery pack lifespan assessment, effectively shortening the overall design verification cycle of the battery pack, improving cycle testing efficiency, and reducing testing costs.

[0071] Optionally, the first test module 21 includes:

[0072] The first test unit is used to perform a cell cycle life test on the cell under at least one test condition, and to record the cell physical parameters before and after the cell cycle life test as the cell test data.

[0073] The test conditions include voltage conditions and / or temperature conditions.

[0074] Optionally, the first test module 21 includes:

[0075] The second testing unit is used to perform a cell calendar life test on the cell under at least one temperature condition, and to record the cell physical parameters before and after the cell calendar life test as the cell test data.

[0076] Optionally, the second test module 22 includes:

[0077] The third test unit is used to perform cycle life test on the battery unit under at least one preset working condition, and record the cell physical parameters of the battery cell before and after the cycle life test as the unit test data.

[0078] The design parameters corresponding to the battery cell are consistent with those of the battery pack to be evaluated. The design parameters include at least one of liquid cooling parameters, environmental parameters, material parameters, and structural parameters.

[0079] Optionally, the physical parameters of the battery cell include at least one of the following: capacity, open-circuit voltage, internal resistance, and mass.

[0080] Optionally, the data analysis module 23 includes:

[0081] The first analysis unit is used to analyze the battery cell test data to determine whether the battery cell is qualified, and...

[0082] The second analysis unit is used to perform data analysis on the unit test data and determine whether the battery unit is qualified.

[0083] The third analysis unit is used to determine that the life evaluation result of the battery pack to be evaluated is qualified if both the battery cell and the battery unit are qualified.

[0084] It should be noted that the battery pack life assessment device provided in this embodiment of the invention can implement all the method steps implemented in the above-mentioned cycle test method embodiment and can achieve the same technical effect. Here, the parts that are the same as those in the method embodiment and the beneficial effects will not be described in detail.

[0085] This invention also provides a testing device, including a memory, a processor, and a computer program stored in the memory and executable on the processor; when the processor executes the computer program, it implements the cyclic testing method described above.

[0086] It should be noted that the testing equipment provided in this embodiment of the invention can implement all the method steps implemented in the above-described cyclic testing method embodiment and can achieve the same technical effect. Therefore, the parts and beneficial effects that are the same as those in the method embodiment will not be described in detail here.

[0087] Those skilled in the art will understand that all or part of the steps of the above embodiments can be implemented by hardware or by a computer program instructing the relevant hardware to implement them. The computer program includes instructions to perform some or all of the steps of the above methods; and the computer program can be stored in a readable storage medium, which can be any form of storage medium.

[0088] This invention provides a readable storage medium storing a program or instructions. When executed by a processor, the program or instructions implement the steps of the loop testing method described above and achieve the same technical effect. To avoid repetition, further details are omitted here. The computer-readable storage medium may include read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk.

[0089] The above describes the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also within the scope of protection of the present invention.

Claims

1. A method for evaluating the lifespan of a battery pack, characterized in that, include: Perform cell life tests on the battery cells and obtain cell test data, wherein the cell life tests include: cell cycle life tests and / or cell calendar life tests; Cycle life tests are performed on the battery cells to obtain cell test data, wherein the battery cells are used to simulate a portion of the cell-to-pack CTP structure within the battery pack to be evaluated, constructed using at least one of the battery cells. Based on the cell test data and the unit test data, the life assessment result of the battery pack to be evaluated is obtained; The step of obtaining the life assessment result of the battery pack to be evaluated based on the cell test data and the unit test data includes: The battery cell test data is analyzed to determine whether the battery cell is qualified, and, The unit test data is analyzed to determine whether the battery unit is qualified. If both the battery cell and the battery unit are qualified, the life evaluation result of the battery pack to be evaluated is determined to be qualified.

2. The method according to claim 1, characterized in that, When the cell life test includes a cell cycle life test, the step of performing a cell life test on the cell and obtaining cell test data includes: Under at least one test condition, the cell is subjected to a cell cycle life test, and the cell physical parameters before and after the cell cycle life test are recorded as the cell test data. The test conditions include voltage conditions and / or temperature conditions.

3. The method according to claim 1, characterized in that, When the cell life test includes a cell calendar life test, the step of performing a cell life test on the cell and obtaining cell test data includes: Under at least one temperature condition, the battery cell is subjected to a battery cell calendar life test, and the battery cell physical parameters before and after the battery cell calendar life test are recorded as the battery cell test data.

4. The method according to claim 1, characterized in that, The cycle life test of the battery cells and the acquisition of cell test data include: Under at least one preset operating condition, the battery cell is subjected to a cycle life test, and the cell physical parameters of the battery cell before and after the cycle life test are recorded as the cell test data. The design parameters corresponding to the battery cell are consistent with those of the battery pack to be evaluated. The design parameters include at least one of liquid cooling parameters, environmental parameters, material parameters, and structural parameters.

5. The method according to any one of claims 2, 3, or 4, characterized in that, The physical parameters of the battery cell include at least one of the following: capacity, open-circuit voltage, internal resistance, and mass.

6. A battery pack life assessment device, characterized in that, include: The first testing module is used to perform cell life testing on the battery cells and obtain cell test data. The cell life testing includes: cell cycle life testing and / or cell calendar life testing. The second test module is used to perform cycle life tests on the battery cells and obtain cell test data. The battery cells are used to simulate a portion of the cell-to-pack CTP structure in the battery pack to be evaluated, which is constructed using at least one of the cells. The data analysis module is used to obtain the life assessment result of the battery pack to be evaluated based on the cell test data and the unit test data; The data analysis module includes: The first analysis unit is used to analyze the battery cell test data to determine whether the battery cell is qualified, and... The second analysis unit is used to perform data analysis on the unit test data and determine whether the battery unit is qualified. The third analysis unit is used to determine that the life evaluation result of the battery pack to be evaluated is qualified if both the battery cell and the battery unit are qualified.

7. A testing device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor; characterized in that, When the processor executes the computer program, it implements the battery pack life assessment method as described in any one of claims 1 to 5.

8. A readable storage medium having a program or instructions stored thereon, characterized in that, When the program or instructions are executed by the processor, they implement the steps in the battery pack life assessment method as described in any one of claims 1 to 5.

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