Method and device for screening out-of-group voltage of lithium ion battery and electronic equipment

Abstract

The invention discloses a lithium ion battery outlier voltage screening method and device and electronic equipment, and belongs to the technical field of lithium batteries, and the method comprises the steps: carrying out the electrical performance test of a prepared battery cell, so as to obtain the electrical performance test result information, and the electrical performance test result information comprises an initial open-circuit voltage value and an initial internal resistance value; carrying out an accelerated aging test on the battery cell, and respectively obtaining a test voltage value and a test internal resistance value of the battery cell at a preset time interval; calculating an average voltage drop rate according to the test voltage value and the initial open-circuit voltage value, and calculating an average internal resistance drop rate according to the test internal resistance value and the initial internal resistance value; comparing the average voltage drop rate with a preset voltage threshold value to judge whether the average voltage drop rate is smaller than the preset voltage threshold value or not; and if yes, determining that the battery cell is an outlier battery cell so as to screen out the outlier battery cell. The technical effects that the detection efficiency is improved, the cost is reduced, and the outlier battery cells can be screened out in time are achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium batteries, and in particular relates to a method, a device and an electronic device for screening outlier voltage of lithium ion batteries. Background Art

[0002] In the field of chemical energy storage, lithium-ion batteries have shown great development potential and have become one of the most promising chemical energy storage power sources. In the production and storage of lithium-ion batteries, the inconsistency of cell voltage has become an important factor restricting the performance of lithium-ion batteries. After the battery pack is manufactured, after a period of warehouse storage, due to the instability of the electrolyte solvent, the poor formation of the solid electrolyte interface film, the defects introduced during the packaging process, and the influence of dust and burrs in the production environment, the voltage drop rate of some cells will be significantly faster than that of other cells, forming an outlier voltage phenomenon. The existence of outlier voltage cells has a significant adverse effect on the overall performance of the battery pack. At present, in lithium battery technology, it is usually after the battery pack is stored that the voltage outliers are screened out by voltage detection. However, in the process of detecting a large number of cells, this detection method requires a large number of cell voltage detections after storage, which is not only time-consuming, but also increases labor costs and is inefficient. At the same time, the storage and detection process itself also requires additional cost investment, which will increase the total cost of the product. In addition, since the change in battery cell performance during storage is irreversible, even if the battery cells with voltage outliers are screened out, it is difficult to restore the performance of the battery cells, so the battery cells with voltage outliers can only be treated as waste, which is not conducive to reducing costs.

[0003] Therefore, it is necessary to provide a new technical solution to solve the above technical problems. Summary of the invention

[0004] The technical problem to be solved by the present invention is the technical problem of low detection efficiency, high cost and inability to timely screen out outlier cells.

[0005] In order to solve the above technical problems, the present invention provides a method for screening outlier voltage of lithium-ion batteries, the method comprising: performing an electrical performance test on a prepared battery cell to obtain electrical performance test result information, the electrical performance test result information comprising an initial open circuit voltage value and an initial internal resistance value; performing an accelerated aging test on the battery cell, and obtaining the test voltage value and the test internal resistance value of the battery cell at preset time intervals; calculating an average voltage drop rate based on the test voltage value and the initial open circuit voltage value, and calculating an average internal resistance drop rate based on the test internal resistance value and the initial internal resistance value; comparing the average voltage drop rate with a preset voltage threshold to determine whether the average voltage drop rate is less than the preset voltage threshold; if so, the battery cell is an outlier battery cell, so as to screen out the outlier battery cell.

[0006] Optionally, calculating the average voltage drop rate based on the test voltage value and the initial open circuit voltage value includes: calculating the average voltage drop rate of the battery cell during the accelerated aging test based on U=|U1-U2| / T×100%; wherein U is the average voltage drop rate, U1 is the initial open circuit voltage value, U2 is the test voltage value of the battery cell, and T is the preset time interval.

[0007] Optionally, after calculating the average voltage drop rate based on the test voltage value and the initial open circuit voltage value, and calculating the average internal resistance drop rate based on the test internal resistance value and the initial internal resistance value, it also includes: comparing the average internal resistance drop rate with a preset internal resistance threshold to determine whether the average internal resistance drop rate is less than the preset internal resistance threshold; if so, the battery cell is an outlier battery cell, so as to screen out the outlier battery cell.

[0008] Optionally, calculating the average internal resistance decrease rate based on the test internal resistance value and the initial internal resistance value includes: calculating the average internal resistance decrease rate of the battery cell during the accelerated aging test based on R=|R1-R2| / T×100%; wherein R is the average internal resistance decrease rate, R1 is the initial internal resistance value, R2 is the test internal resistance value of the battery cell, and T is the preset time interval.

[0009] Optionally, the preset time interval includes 7 days, 15 days, 30 days, 45 days and 60 days.

[0010] Optionally, performing the accelerated aging test on the battery cell includes: storing the battery cell at a preset temperature, and charging and discharging the battery cell according to a preset number of cycles.

[0011] Optionally, the preset temperature is 20°C to 30°C; and the number of cycles is 10 to 15 times.

[0012] According to another aspect of the present invention, the present invention also provides a device for screening outlier voltages of lithium-ion batteries, the device comprising: an electrical performance testing module, used to perform an electrical performance test on a prepared battery cell to obtain electrical performance test result information, the electrical performance test result information comprising an initial open circuit voltage value and an initial internal resistance value; an aging testing module, used to perform an accelerated aging test on the battery cell, and obtain the test voltage value and the test internal resistance value of the battery cell at preset time intervals; a calculation module, used to calculate an average voltage drop rate based on the test voltage value and the initial open circuit voltage value, and to calculate an average internal resistance drop rate based on the test internal resistance value and the initial internal resistance value; a voltage judgment module, used to compare the average voltage drop rate with a preset voltage threshold to determine whether the average voltage drop rate is less than the preset voltage threshold; and a screening module, used to determine if the battery cell is an outlier cell, so as to screen out the outlier cell.

[0013] Optionally, the device further includes: an internal resistance judgment module, configured to compare the average internal resistance decrease rate with a preset internal resistance threshold value to judge whether the average internal resistance decrease rate is less than the preset internal resistance threshold value.

[0014] According to another aspect of the present invention, the present invention also provides an electronic device for screening outlier voltages of lithium-ion batteries, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the following steps when executing the program: performing an electrical performance test on a prepared battery cell to obtain electrical performance test result information, wherein the electrical performance test result information includes an initial open circuit voltage value and an initial internal resistance value; performing an accelerated aging test on the battery cell to obtain a test voltage value and a test internal resistance value of the battery cell at preset time intervals; calculating an average voltage drop rate based on the test voltage value and the initial open circuit voltage value, and calculating an average internal resistance drop rate based on the test internal resistance value and the initial internal resistance value; comparing the average voltage drop rate with a preset voltage threshold to determine whether the average voltage drop rate is less than the preset voltage threshold; if so, the battery cell is an outlier battery cell to screen out the outlier battery cell.

[0015] Beneficial effects:

[0016] The present invention provides a method for screening outlier voltage of lithium-ion batteries, which is performed by performing an electrical performance test on a prepared battery cell to obtain electrical performance test result information, wherein the electrical performance test result information includes an initial open circuit voltage value and an initial internal resistance value; performing an accelerated aging test on the battery cell, and obtaining the test voltage value and the test internal resistance value of the battery cell at preset time intervals; calculating an average voltage drop rate based on the test voltage value and the initial open circuit voltage value, and calculating an average internal resistance drop rate based on the test internal resistance value and the initial internal resistance value; comparing the average voltage drop rate with a preset voltage threshold to determine whether the average voltage drop rate is less than the preset voltage threshold; if so, the battery cell is an outlier battery cell, so as to screen out the outlier battery cell. In this way, the initial open circuit voltage value, initial internal resistance value, test voltage value and test internal resistance value of the battery cell are obtained through electrical performance testing and accelerated aging testing, and then the outlier battery cell is screened out by comparing the calculated average voltage drop rate with the preset voltage threshold. Thereby achieving the technical effect of improving detection efficiency, reducing costs, and being able to screen outlier cells in a timely manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 A flow chart of a method for screening outlier voltage of a lithium-ion battery provided by an embodiment of the present invention.

[0019] Figure 2 A structural block diagram of a device for screening outlier voltage of a lithium-ion battery provided by an embodiment of the present invention.

[0020] Figure 3 A structural diagram of an electronic device for screening outlier voltage of a lithium-ion battery provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention belong to the scope of protection of the present invention; the "and / or" keyword involved in this implementation represents both and, or. In other words, A and / or B mentioned in the embodiments of the present invention represent both A and B, and A or B, and describe the three states of A and B. For example, A and / or B means: only A is included but not B; only B is included but not A; both A and B are included.

[0022] It should be understood that although the terms "first", "second", etc. can be used here to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Therefore, without departing from the teachings of the exemplary embodiments, the first element, component, region, layer or section discussed below can be referred to as the second element, component, region, layer or section. Spatially related terms such as "below", "above", etc. can be used here to facilitate the description of the relationship between one element or feature and another element or feature. It is understood that in addition to the orientation shown in the figure, spatially relative terms also include different orientations of the device in use or operation. For example, if the device in the figure is turned over, the element or feature described as "below" will be oriented as "above" other elements or features. Therefore, the exemplary term "below" can include both above and below orientations. The device can be oriented (rotated 90 degrees or in other orientations), and the spatially related descriptors used here are interpreted accordingly.

[0023] See also Figure 1 , Figure 1 1 is a flow chart of a method for screening outlier voltage of a lithium-ion battery provided by an embodiment of the present invention. A method for screening outlier voltage of a lithium-ion battery provided by an embodiment of the present invention comprises the following steps:

[0024] Step S100, performing an electrical performance test on the prepared battery cell to obtain electrical performance test result information, wherein the electrical performance test result information includes an initial open circuit voltage value and an initial internal resistance value;

[0025] Specifically, after the battery cell preparation is completed, the prepared battery cell can be immediately placed in the electrical performance testing equipment, and the testing equipment can be started to perform an electrical performance test on the battery cell. During the test, the equipment will automatically record the initial open circuit voltage value and initial internal resistance value of the battery cell, and output the initial open circuit voltage value and initial internal resistance value as the electrical performance test result information, which serves as the benchmark data for the subsequent calculation of the average voltage drop rate and the average internal resistance drop rate.

[0026] Step S200, performing an accelerated aging test on the battery cell, and obtaining a test voltage value and a test internal resistance value of the battery cell at preset time intervals;

[0027] The accelerated aging test of the battery cell includes: storing the battery cell at a preset temperature, and charging and discharging the battery cell according to a preset number of cycles. The preset temperature is 20°C to 30°C; the number of cycles is 10 to 15 times. The preset time interval includes 7 days, 15 days, 30 days, 45 days and 60 days.

[0028] Specifically, the battery cell can be placed in a temperature environment of 42°C to 48°C for storage, and the battery cell can be cycled and discharged for 10 to 15 times. And the test voltage value and test internal resistance value of the battery cell are obtained on the 7th day, the 15th day, the 30th day, the 45th day and the 60th day, respectively. For example, when the battery cell is stored for the 7th day, the first test voltage value and the first test internal resistance value of the battery cell are measured for the first time, when the battery cell is stored for the 15th day, the second test voltage value and the second test internal resistance value of the battery cell are measured for the second time, when the battery cell is stored for the 30th day, the third test voltage value and the third test internal resistance value of the battery cell are measured for the third time, when the battery cell is stored for the 45th day, the fourth test voltage value and the fourth test internal resistance value of the battery cell are measured for the fourth time, and when the battery cell is stored for the 60th day, the fifth test voltage value and the fifth test internal resistance value of the battery cell are measured for the fifth time. Through accelerated aging testing, the performance changes of the battery cell during actual use can be simulated.

[0029] Step S300, calculating an average voltage drop rate according to the test voltage value and the initial open circuit voltage value, and calculating an average internal resistance drop rate according to the test internal resistance value and the initial internal resistance value;

[0030] The calculation of the average voltage drop rate based on the test voltage value and the initial open circuit voltage value includes: calculating the average voltage drop rate of the battery cell during the accelerated aging test based on U=|U1-U2| / T×100%; wherein U is the average voltage drop rate, U1 is the initial open circuit voltage value, U2 is the test voltage value of the battery cell, and T is the preset time interval.

[0031] In addition, the calculation of the average voltage drop rate based on the test voltage value and the initial open circuit voltage value, and the calculation of the average internal resistance drop rate based on the test internal resistance value and the initial internal resistance value also includes: comparing the average internal resistance drop rate with a preset internal resistance threshold to determine whether the average internal resistance drop rate is less than the preset internal resistance threshold; if so, the battery cell is an outlier battery cell, so as to screen out the outlier battery cell. The calculation of the average internal resistance drop rate based on the test internal resistance value and the initial internal resistance value includes: calculating the average internal resistance drop rate of the battery cell during the accelerated aging test based on R=|R1-R2| / T×100%; wherein R is the average internal resistance drop rate, R1 is the initial internal resistance value, R2 is the test internal resistance value of the battery cell, and T is the preset time interval.

[0032] Specifically, after obtaining the first test voltage value and the first test internal resistance value, the second test voltage value and the second test internal resistance value, the third test voltage value and the third test internal resistance value, the fourth test voltage value and the fourth test internal resistance value, and the fifth test voltage value and the fifth test internal resistance value through the above step S200, the average voltage drop rate and the average internal resistance drop rate can be calculated respectively. For example, when the first test voltage value and the first test internal resistance value of the battery cell are measured for the first time, the first average voltage drop rate of the battery cell during the accelerated aging test is calculated according to U=|U1-U2| / T×100%, at which time the first test voltage value is the above U2, the initial open circuit voltage value obtained in step S100 is the above U1, and T is 7. When the second test voltage value and the second test internal resistance value of the battery cell are measured for the second time, the second average voltage drop rate of the battery cell during the accelerated aging test is calculated according to U=|U1-U2| / T×100%. At this time, the second test voltage value is the above-mentioned U2, the initial open circuit voltage value obtained in step S100 is the above-mentioned U1, and T is 15. According to the above steps, the first average voltage drop rate, the second average voltage drop rate, the third average voltage drop rate, the fourth average voltage drop rate, and the fifth average voltage drop rate corresponding to 7 days, 15 days, 30 days, 45 days, and 60 days can be calculated respectively. Similarly, the first average internal resistance drop rate, the second average internal resistance drop rate, the third average internal resistance drop rate, the fourth average internal resistance drop rate, and the fifth average internal resistance drop rate corresponding to the 7th day, the 15th day, the 30th day, the 45th day, and the 60th day can also be calculated respectively. In addition, the first average internal resistance decrease rate, the second average internal resistance decrease rate, the third average internal resistance decrease rate, the fourth average internal resistance decrease rate, and the fifth average internal resistance decrease rate can be compared with the preset internal resistance threshold, respectively, to determine whether the average internal resistance decrease rate is less than the preset internal resistance threshold. For example, the first average internal resistance decrease rate is compared with the preset internal resistance threshold. If the first average internal resistance decrease rate is less than the preset internal resistance threshold, the battery cell is determined to be an outlier battery cell, that is, any one of the above average internal resistance decrease rates is compared with the preset internal resistance threshold. When one of the average internal resistance decrease rates is less than the preset internal resistance threshold, the battery cell is determined to be an outlier battery cell, otherwise the battery cell is not an outlier battery cell. The preset internal resistance threshold corresponding to the 7th day is 0.008mΩ / d, the preset internal resistance threshold corresponding to the 15th day is 0.012mΩ / d, the preset internal resistance threshold corresponding to the 30th day is 0.018mΩ / d, the preset internal resistance threshold corresponding to the 45th day is 0.018mΩ / d, and the preset internal resistance threshold corresponding to the 60th day is 0.025mΩ / d.

[0033] Step S400, comparing the average voltage drop rate with a preset voltage threshold to determine whether the average voltage drop rate is less than the preset voltage threshold;

[0034] Specifically, after calculating the first average voltage drop rate, the second average voltage drop rate, the third average voltage drop rate, the fourth average voltage drop rate, and the fifth average voltage drop rate through the above step S300, the first average voltage drop rate, the second average voltage drop rate, the third average voltage drop rate, the fourth average voltage drop rate, and the fifth average voltage drop rate can be compared with the corresponding preset voltage thresholds to determine whether the average voltage drop rate is less than the preset voltage threshold. The preset voltage threshold corresponding to the 7th day is 1.02mV / d, the preset voltage threshold corresponding to the 15th day is 0.45mV / d, the preset voltage threshold corresponding to the 30th day is 0.26mV / d, the preset voltage threshold corresponding to the 45th day is 0.26mV / d, and the preset voltage threshold corresponding to the 60th day is 0.11mV / d. For example, the first average voltage drop rate is compared with the preset voltage threshold. If the first average voltage drop rate is greater than 1.02mV / d, it is determined that the battery cell is not an outlier battery cell. The second average voltage drop rate is compared with the preset voltage threshold, and if the second average voltage drop rate is greater than 0.45mV / d, it is determined that the battery cell is not an outlier. That is, any of the above average voltage drop rates is compared with the preset voltage threshold, and when one of the average voltage drop rates is greater than the preset voltage threshold, it is determined that the battery cell is not an outlier.

[0035] Step S500: If yes, the battery cell is an outlier battery cell, so as to screen out the outlier battery cell.

[0036] Specifically, when the average voltage drop rate is compared with the preset voltage threshold in the above step S400, if any of the above average voltage drop rates is compared with the preset voltage threshold, when one of the average voltage drop rates is less than the preset voltage threshold, it is determined that the battery cell is an outlier battery cell. Through the final screening, not only can the detection efficiency be improved and the cost be reduced, but also the overall quality of the battery cell batch can be ensured, and the reliability and safety of the product can be improved.

[0037] The present invention provides a method for screening outlier voltage of lithium-ion batteries, which is performed by performing an electrical performance test on a prepared battery cell to obtain electrical performance test result information, wherein the electrical performance test result information includes an initial open circuit voltage value and an initial internal resistance value; performing an accelerated aging test on the battery cell, and obtaining the test voltage value and the test internal resistance value of the battery cell at preset time intervals; calculating an average voltage drop rate based on the test voltage value and the initial open circuit voltage value, and calculating an average internal resistance drop rate based on the test internal resistance value and the initial internal resistance value; comparing the average voltage drop rate with a preset voltage threshold to determine whether the average voltage drop rate is less than the preset voltage threshold; if so, the battery cell is an outlier battery cell, so as to screen out the outlier battery cell. In this way, the initial open circuit voltage value, initial internal resistance value, test voltage value and test internal resistance value of the battery cell are obtained through electrical performance testing and accelerated aging testing, and then the outlier battery cell is screened out by comparing the calculated average voltage drop rate with the preset voltage threshold. Thereby achieving the technical effect of improving detection efficiency, reducing costs, and being able to screen outlier cells in a timely manner.

[0038] In order to explain in detail the device for screening outlier voltage of lithium-ion batteries provided by the present invention, the above-mentioned embodiment 1 describes in detail a method for screening outlier voltage of lithium-ion batteries. Based on the same inventive concept, the present application also provides a device for screening outlier voltage of lithium-ion batteries, see embodiment 2 for details.

[0039] See also Figure 2 , Figure 2 : is a structural block diagram of a device for screening outlier voltage of a lithium-ion battery provided by an embodiment of the present invention. Embodiment 2 of the present invention provides a device for screening outlier voltage of a lithium-ion battery, the device comprising:

[0040] The electrical performance test module 200 is used to perform an electrical performance test on the prepared battery cell to obtain electrical performance test result information, wherein the electrical performance test result information includes an initial open circuit voltage value and an initial internal resistance value;

[0041] An aging test module 210 is used to perform an accelerated aging test on the battery cell, and obtain a test voltage value and a test internal resistance value of the battery cell at preset time intervals;

[0042] A calculation module 220, configured to calculate an average voltage drop rate according to the test voltage value and the initial open circuit voltage value, and to calculate an average internal resistance drop rate according to the test internal resistance value and the initial internal resistance value;

[0043] A voltage determination module 230, configured to compare the average voltage drop rate with a preset voltage threshold to determine whether the average voltage drop rate is less than the preset voltage threshold;

[0044] The screening module 240 is used to screen out the outlier battery cell if the battery cell is an outlier battery cell.

[0045] Embodiment 2 of the present invention provides a device for screening outlier voltage of lithium-ion batteries, which also includes: an internal resistance judgment module, used to compare the average internal resistance decrease rate with a preset internal resistance threshold to determine whether the average internal resistance decrease rate is less than the preset internal resistance threshold.

[0046] The present invention provides a device for screening outlier voltage of lithium-ion batteries, which performs an electrical performance test on a prepared battery cell to obtain electrical performance test result information, wherein the electrical performance test result information includes an initial open circuit voltage value and an initial internal resistance value; performs an accelerated aging test on the battery cell, and obtains the test voltage value and the test internal resistance value of the battery cell at preset time intervals; calculates an average voltage drop rate based on the test voltage value and the initial open circuit voltage value, and calculates an average internal resistance drop rate based on the test internal resistance value and the initial internal resistance value; compares the average voltage drop rate with a preset voltage threshold to determine whether the average voltage drop rate is less than the preset voltage threshold; if so, the battery cell is an outlier battery cell, so as to screen out the outlier battery cell. In this way, the initial open circuit voltage value, initial internal resistance value, test voltage value and test internal resistance value of the battery cell are obtained through electrical performance testing and accelerated aging testing, and then the outlier battery cell is screened out by comparing the calculated average voltage drop rate with the preset voltage threshold. Thereby achieving the technical effect of improving detection efficiency, reducing costs, and being able to screen outlier cells in a timely manner.

[0047] In order to explain in detail an electronic device for screening outlier voltage of lithium-ion batteries provided by the present invention, the above-mentioned embodiment one describes in detail a method for screening outlier voltage of lithium-ion batteries. Based on the same inventive concept, the present application also provides an electronic device for screening outlier voltage of lithium-ion batteries, see embodiment three for details.

[0048] See also Figure 3 , Figure 3It is a structural diagram of an electronic device for screening outlier voltage of lithium-ion batteries provided by an embodiment of the present invention. Embodiment 3 of the present invention provides an electronic device for screening outlier voltage of lithium-ion batteries, including a memory 310, a processor 320, and a computer program 311 stored in the memory 310 and executable on the processor 320, wherein the processor 320 implements the following steps when executing the program: conducting an electrical performance test on the prepared battery cell to obtain electrical performance test result information, wherein the electrical performance test result information includes an initial open circuit voltage value and an initial internal resistance value; conducting an accelerated aging test on the battery cell, and obtaining the test voltage value and the test internal resistance value of the battery cell at preset time intervals; calculating the average voltage drop rate based on the test voltage value and the initial open circuit voltage value, and calculating the average internal resistance drop rate based on the test internal resistance value and the initial internal resistance value; comparing the average voltage drop rate with a preset voltage threshold value to determine whether the average voltage drop rate is less than the preset voltage threshold value; if so, the battery cell is an outlier battery cell, so as to screen out the outlier battery cell.

[0049] The present invention provides an electronic device for screening outlier voltages of lithium-ion batteries, wherein the electronic device performs an electrical performance test on a prepared battery cell to obtain electrical performance test result information, wherein the electrical performance test result information includes an initial open circuit voltage value and an initial internal resistance value; performs an accelerated aging test on the battery cell, and obtains the test voltage value and the test internal resistance value of the battery cell at preset time intervals; calculates an average voltage drop rate based on the test voltage value and the initial open circuit voltage value, and calculates an average internal resistance drop rate based on the test internal resistance value and the initial internal resistance value; compares the average voltage drop rate with a preset voltage threshold to determine whether the average voltage drop rate is less than the preset voltage threshold; if so, the battery cell is an outlier battery cell, so as to screen out the outlier battery cell. In this way, the initial open circuit voltage value, initial internal resistance value, test voltage value, and test internal resistance value of the battery cell are obtained through electrical performance testing and accelerated aging testing, and then the outlier battery cell is screened out by comparing the calculated average voltage drop rate with the preset voltage threshold. Thereby achieving the technical effect of improving detection efficiency, reducing costs, and being able to screen outlier cells in a timely manner.

[0050] In some embodiments, the device provided by the embodiments of the present disclosure may also have functions or include modules that can be used to execute the method described in the above method embodiments. Its specific implementation can refer to the description of the above method embodiments, and for the sake of brevity, it will not be repeated here.

[0051] The above description of various embodiments tends to emphasize the differences between the various embodiments. The same or similar aspects can be referenced to each other, and for the sake of brevity, they will not be repeated herein.

[0052] In the several embodiments provided in the present application, it should be understood that the disclosed methods and devices can be implemented in other ways. For example, the device implementation described above is only schematic. For example, the division of modules or units is only a logical function division. There may be other division methods in actual implementation, such as units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, and the indirect coupling or communication connection of devices or units can be electrical, mechanical or other forms.

[0053] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0054] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, server, or network device, etc.) or a processor (processor) to perform all or part of the steps of each implementation method of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program code.

[0055] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A method for screening outlier voltage of lithium ion batteries, characterized in that: The method comprises: Conducting an electrical performance test on the prepared battery cell to obtain electrical performance test result information, wherein the electrical performance test result information includes an initial open circuit voltage value and an initial internal resistance value; Performing an accelerated aging test on the battery cell, and obtaining a test voltage value and a test internal resistance value of the battery cell at preset time intervals; Calculating an average voltage drop rate according to the test voltage value and the initial open circuit voltage value, and calculating an average internal resistance drop rate according to the test internal resistance value and the initial internal resistance value; Comparing the average voltage drop rate with a preset voltage threshold to determine whether the average voltage drop rate is less than the preset voltage threshold; If so, the battery cell is an outlier battery cell, so that the outlier battery cell is screened out.

2. The method for screening outlier voltage of a lithium ion battery according to claim 1, characterized in that: The calculation of the average voltage drop rate based on the test voltage value and the initial open circuit voltage value includes: calculating the average voltage drop rate of the battery cell during the accelerated aging test based on U=|U1-U2| / T×100%; wherein U is the average voltage drop rate, U1 is the initial open circuit voltage value, U2 is the test voltage value of the battery cell, and T is the preset time interval.

3. The method for screening outlier voltage of lithium ion batteries according to claim 1, characterized in that: After calculating the average voltage drop rate based on the test voltage value and the initial open circuit voltage value, and calculating the average internal resistance drop rate based on the test internal resistance value and the initial internal resistance value, the method further includes: comparing the average internal resistance drop rate with a preset internal resistance threshold value to determine whether the average internal resistance drop rate is less than the preset internal resistance threshold value; if so, the battery cell is an outlier battery cell to screen out the outlier battery cell.

4. The method for screening outlier voltage of lithium ion batteries according to claim 3, characterized in that: The method of calculating the average internal resistance decrease rate based on the test internal resistance value and the initial internal resistance value includes: calculating the average internal resistance decrease rate of the battery cell during the accelerated aging test based on R=|R1-R2| / T×100%; wherein R is the average internal resistance decrease rate, R1 is the initial internal resistance value, R2 is the test internal resistance value of the battery cell, and T is the preset time interval.

5. The method for screening outlier voltage of a lithium ion battery according to claim 2 or 4, characterized in that: The preset time interval includes 7 days, 15 days, 30 days, 45 days and 60 days.

6. The method for screening outlier voltage of lithium ion batteries according to claim 1, characterized in that: The accelerated aging test on the battery cell includes: storing the battery cell at a preset temperature, and charging and discharging the battery cell according to a preset number of cycles.

7. The method for screening outlier voltage of a lithium ion battery according to claim 6, characterized in that: The preset temperature is 20° C. to 30° C.; the number of cycles is 10 to 15 times.

8. A device for screening outlier voltage of lithium-ion batteries, characterized in that: The device comprises: An electrical performance test module is used to perform an electrical performance test on the prepared battery cell to obtain electrical performance test result information, wherein the electrical performance test result information includes an initial open circuit voltage value and an initial internal resistance value; An aging test module, used to perform an accelerated aging test on the battery cell, and obtain a test voltage value and a test internal resistance value of the battery cell at preset time intervals; A calculation module, used to calculate an average voltage drop rate according to the test voltage value and the initial open circuit voltage value, and to calculate an average internal resistance drop rate according to the test internal resistance value and the initial internal resistance value; A voltage judgment module, used for comparing the average voltage drop rate with a preset voltage threshold to judge whether the average voltage drop rate is less than the preset voltage threshold; A screening module is used to screen out the outlier battery cell if the battery cell is an outlier battery cell.

9. The device for screening outlier voltage of lithium-ion batteries according to claim 8, characterized in that: The device further includes: an internal resistance judgment module, which is used to compare the average internal resistance decrease rate with a preset internal resistance threshold value to judge whether the average internal resistance decrease rate is less than the preset internal resistance threshold value.

10. An electronic device for screening outlier voltage of a lithium-ion battery, 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 program, the following steps are implemented: Conducting an electrical performance test on the prepared battery cell to obtain electrical performance test result information, wherein the electrical performance test result information includes an initial open circuit voltage value and an initial internal resistance value; Performing an accelerated aging test on the battery cell, and obtaining a test voltage value and a test internal resistance value of the battery cell at preset time intervals; Calculating an average voltage drop rate according to the test voltage value and the initial open circuit voltage value, and calculating an average internal resistance drop rate according to the test internal resistance value and the initial internal resistance value; Comparing the average voltage drop rate with a preset voltage threshold to determine whether the average voltage drop rate is less than the preset voltage threshold; If so, the battery cell is an outlier battery cell, so that the outlier battery cell is screened out.

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