Method and device for screening retired power batteries for cascade utilization

Abstract

The present invention discloses a method and device for screening retired power batteries for cascade utilization, which performs appearance screening on battery cells; wherein, the battery cells are removed from the retired power batteries, and voltage detection is performed on the battery cells that pass the appearance screening, and multiple characteristic test items are tested on the battery cells that pass the voltage detection at different ambient temperatures. Based on the test results of the multiple characteristic test items, the battery cells are classified and reorganized. In this way, by performing multiple characteristic test items on the battery cells at different ambient temperatures, the battery condition data under the influence of different ambient temperatures can be reflected, thereby achieving accurate screening.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a method and device for screening retired power batteries for cascade utilization. Background Art

[0002] With the widespread adoption of electric vehicles, power battery production has also increased significantly, raising the question of how to dispose of retired electric vehicle power batteries. When a lithium-ion battery's capacity decays to 80% of its original capacity, it is no longer suitable for use in electric vehicles. However, if the battery is in good condition, undamaged, and its functional components are functioning properly, it can be reused in a cascaded manner, for example as a storage device for clean energy sources such as solar and wind power, as well as for power grids and microgrids. Reusing retired power batteries in a cascaded manner can significantly reduce carbon emissions. However, the performance of retired power batteries from electric vehicles varies, requiring rigorous screening to eliminate the small number of problematic batteries that are no longer consistent with the majority. Only through proper screening can cascaded reuse ensure their full value.

[0003] In the related art, there is a single parameter screening method, which screens the batteries by measuring the capacity, internal resistance, self-discharge rate or open circuit voltage of the batteries to be screened. The advantage of the single parameter screening method is that it is fast, but the disadvantage is that it is not accurate enough. Therefore, the dynamic operating conditions of the lithium-ion batteries after they are actually grouped are poor. For retired batteries, the battery packs obtained by single parameter screening have large differences between single cells under actual operating conditions, which leads to accelerated aging of the entire battery pack. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the present invention provides a method for screening retired power batteries for cascade utilization, comprising:

[0005] Performing appearance screening on battery cells; wherein the battery cells are removed from retired power batteries;

[0006] Conduct voltage testing on battery cells that have passed the appearance screening;

[0007] Under different ambient temperatures, multiple characteristic test items are tested on battery cells that have passed the voltage test;

[0008] Based on the test results of multiple characteristic test items, the battery cells are classified and reorganized.

[0009] In one embodiment, during the test operation of each characteristic test item, the following operations are performed:

[0010] According to the preset installation rules, N temperature sensors are respectively installed at different positions of the battery cells;

[0011] determining a standard temperature curve set corresponding to the current ambient temperature based on a pre-configured mapping relationship between the ambient temperature and the standard temperature curve set; wherein the standard temperature curve set includes N standard temperature curves, each of the N standard temperature curves corresponding one-to-one to N temperature sensors disposed at different locations of the battery cell according to the preset installation rule, and each standard temperature curve is a curve formed based on temperature data collected at different times by the corresponding temperature sensor when the battery cell is tested in a factory state according to the preset characteristic test rule;

[0012] When testing the characteristic test items of battery cells, the temperature test curves of N temperature sensors are recorded in real time;

[0013] Based on N standard temperature curves and temperature test curves of N temperature sensors, test results of characteristic test items of the battery cell are corrected.

[0014] In one embodiment, the correction of the test results of the characteristic test items of the battery cell based on the N standard temperature curves and the temperature test curves of the N temperature sensors specifically includes:

[0015] Determine a test correction factor based on N standard temperature curves and temperature test curves of N temperature sensors;

[0016] Based on the mapping relationship between the pre-configured weights of the temperature sensors and the standard temperature curves, respectively determine the weights of the N temperature sensors corresponding to the N standard temperature curves;

[0017] Based on the test correction coefficient and the weight of the temperature sensor, the test results of the characteristic test items of the battery cell are corrected.

[0018] In one embodiment, determining the test correction coefficient based on the N standard temperature curves and the temperature test curves of the N temperature sensors specifically includes:

[0019] For each temperature test curve, the test correction coefficient is calculated using the following formula:

[0020]

[0021] Among them, t represents different test moments, t∈{1, 2,…, t s}; i represents the serial number of different sensors and the serial number of different standard temperature curves, i∈{1, 2, ..., N}; x i is the test correction coefficient corresponding to the i-th temperature test curve; t s T is the total test time of the current feature test item; it is the temperature value of the ith temperature test curve at time t; T btis the temperature value of the i-th standard temperature curve at the t-th moment.

[0022] In one embodiment, the correction of the test results of the characteristic test items of the battery cell based on the test correction coefficient and the weight of the temperature sensor specifically includes:

[0023] The test results of the battery cell characteristic test items are corrected using the following formula:

[0024]

[0025] Wherein, Y is the test result of the characteristic test item of the battery cell, and Z is the test result of the characteristic test item of the battery cell after correction; q i is the weight of the i-th temperature sensor.

[0026] In one embodiment, the plurality of characteristic test items include at least one of capacity detection, internal resistance detection, self-discharge rate detection, and open circuit voltage detection.

[0027] In one embodiment, the appearance screening of the battery cells specifically includes:

[0028] Check whether the battery cells are damaged or the electrolyte is leaking;

[0029] When electrolyte leakage or damage is detected in a battery cell, the currently measured battery cell will be recycled and reused;

[0030] When no damage or electrolyte leakage is detected in the battery cell, the currently measured battery cell size is compared with the pre-stored corresponding battery cell size information. If the deformation of the battery cell exceeds the preset deformation threshold, the currently measured battery cell is recycled and reused.

[0031] In order to solve the same technical problem, an embodiment of the present invention further provides a retired power battery recycling screening device, comprising:

[0032] An appearance screening module, used to perform appearance screening on battery cells; wherein the battery cells are removed from retired power batteries;

[0033] Voltage detection module, used to perform voltage detection on battery cells that have passed the appearance screening;

[0034] The test module is used to perform multiple characteristic test operations on battery cells that have passed the voltage test at different ambient temperatures;

[0035] The classification module is used to classify and reorganize battery cells based on the test results of multiple characteristic test items.

[0036] In one embodiment, the test operation method for each characteristic test item in the test operation of the plurality of characteristic test items is as follows:

[0037] According to the preset installation rules, N temperature sensors are respectively installed at different positions of the battery cells;

[0038] determining a standard temperature curve set corresponding to the current ambient temperature based on a pre-configured mapping relationship between the ambient temperature and the standard temperature curve set; wherein the standard temperature curve set includes N standard temperature curves, each of the N standard temperature curves corresponding one-to-one to N temperature sensors disposed at different locations of the battery cell according to the preset installation rule, and each standard temperature curve is a curve formed based on temperature data collected at different times by the corresponding temperature sensor when the battery cell is tested in a factory state according to the preset characteristic test rule;

[0039] When testing the characteristic test items of battery cells, the temperature test curves of N temperature sensors are recorded in real time;

[0040] Based on N standard temperature curves and temperature test curves of N temperature sensors, test results of characteristic test items of the battery cell are corrected.

[0041] In one embodiment, the plurality of characteristic test items include at least one of capacity detection, internal resistance detection, self-discharge rate detection, and open circuit voltage detection.

[0042] Compared with the prior art, the beneficial effects of the embodiments of the present invention are as follows: the embodiments of the present invention provide a method and device for screening retired power batteries for cascade utilization, by performing appearance screening on battery cells; wherein, the battery cells are removed from the retired power batteries, and voltage detection is performed on the battery cells that have passed the appearance screening, and multiple characteristic test items are tested on the battery cells that have passed the voltage detection at different ambient temperatures. Based on the test results of the multiple characteristic test items, the battery cells are classified and reorganized. In this way, by performing multiple characteristic test items on the battery cells at different ambient temperatures, the battery status data under the influence of different ambient temperatures can be reflected, thereby achieving accurate screening. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 1 is a flow chart of a method for screening the recycling of retired power batteries according to an embodiment of the present invention;

[0044] Figure 2 It is a structural block diagram of a retired power battery recycling screening device in an embodiment of the present invention. DETAILED DESCRIPTION

[0045] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 without making any creative efforts shall fall within the scope of protection of the present invention.

[0046] See also Figure 1 , which is a flow chart of the method for screening the cascade utilization of retired power batteries in an embodiment of the present invention.

[0047] The method for screening retired power batteries for reuse according to an embodiment of the present invention includes:

[0048] Step S101, performing appearance screening on battery cells; wherein the battery cells are removed from retired power batteries;

[0049] Step S102, performing voltage testing on battery cells that have passed the appearance screening;

[0050] Step S103, performing a plurality of characteristic test operations on the battery cells that have passed the voltage test at different ambient temperatures;

[0051] Step S104 : classifying and reorganizing the battery cells based on the test results of the multiple characteristic test items.

[0052] It should be noted that the significance of testing battery cells at different temperatures lies in that if the same test values ​​of the battery cells under various temperature conditions are close, it means that the performance of each battery cell under different environmental conditions is similar, which facilitates the selection of battery cells with similar performance. Therefore, by testing battery cells with multiple characteristic test items at different ambient temperatures, the battery condition data under the influence of different ambient temperatures is reflected, thus achieving accurate screening.

[0053] Exemplarily, different ambient temperatures may be, for example, 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, etc. Of course, the specific ambient temperature can also be set according to actual test requirements, which will not be described in detail here. The multiple characteristic test items include at least one of capacity detection, internal resistance detection, self-discharge rate detection, and open circuit voltage detection. Of course, other types of characteristic test items can also be performed according to actual test requirements, which will not be described in detail here.

[0054] In one embodiment, the step S101 of “screening the battery cells by appearance” specifically includes:

[0055] Check whether the battery cells are damaged or the electrolyte is leaking;

[0056] When electrolyte leakage is detected in a battery cell, the battery cell currently being measured will be scrapped;

[0057] When a battery cell is detected to be damaged but no electrolyte leakage occurs, the currently measured battery cell is recycled and reused;

[0058] When no damage or electrolyte leakage is detected in the battery cell, the currently measured battery cell size is compared with the pre-stored corresponding battery cell size information. If the deformation of the battery cell exceeds the preset deformation threshold, the currently measured battery cell is recycled and reused.

[0059] For example, the appearance of single cells can be screened by machine vision technology, industrial CT or X-ray technology, and qualified single cells can be screened for further screening. The deformation of the battery cell is, for example, bulging deformation. In this embodiment, by detecting whether the battery cell is damaged, the electrolyte is leaking, and the deformation is present, the obviously defective battery cells are first screened out by a simple screening method. Such obviously defective battery cells cannot be used in a gradient manner, thereby reducing the workload of subsequent testing and improving the overall test efficiency. Battery cells that are not detected to be damaged, leaking electrolyte, and whose deformation does not exceed the preset deformation threshold are battery cells that have passed the appearance screening. Among them, the preset deformation threshold can be set according to the actual test requirements, and no further details are given here.

[0060] In addition, the battery cells that pass the voltage test in step S102 are battery cells whose test results are within a preset voltage range when the battery cells that pass the appearance screening are subjected to voltage testing. The preset voltage range can be set according to actual test requirements and will not be further elaborated here.

[0061] In one embodiment, during the test operation of each characteristic test item, the following operations are performed:

[0062] According to the preset installation rules, N temperature sensors are respectively installed at different positions of the battery cells;

[0063] determining a standard temperature curve set corresponding to the current ambient temperature based on a pre-configured mapping relationship between the ambient temperature and the standard temperature curve set; wherein the standard temperature curve set includes N standard temperature curves, each of the N standard temperature curves corresponding one-to-one to N temperature sensors disposed at different locations of the battery cell according to the preset installation rule, and each standard temperature curve is a curve formed based on temperature data collected at different times by the corresponding temperature sensor when the battery cell is tested in a factory state according to the preset characteristic test rule;

[0064] When testing the characteristic test items of battery cells, the temperature test curves of N temperature sensors are recorded in real time;

[0065] Based on N standard temperature curves and temperature test curves of N temperature sensors, test results of characteristic test items of the battery cell are corrected.

[0066] In this embodiment, considering that the surface temperature of battery cells during testing can be affected by the ambient temperature, a mapping relationship between the ambient temperature and a set of standard temperature curves is preconfigured to correct for test errors caused by changes in the surface temperature of battery cells during testing, thereby improving test accuracy and, in turn, the accuracy of battery screening. The pre-set installation rules may, for example, uniformly arrange N temperature sensors on the surface of a battery cell. Alternatively, N temperature sensors may be arranged on the surface of a battery cell to measure the surface temperature of the battery cell according to actual testing requirements. The pre-set characteristic test rules define predefined test procedures for different characteristic test items for a battery cell. It should be noted that the number of temperature sensors can be, for example, 5, 6, 7, 8, 9, 10, 11, 12, 13, etc., and can also be adjusted based on actual usage requirements. The placement of each sensor can also be adjusted based on actual usage requirements. Further details are not provided here.

[0067] In specific implementation, the mapping relationship between the ambient temperature and the standard temperature curve set can be set before the actual test, and does not need to be set every time the actual test is performed. The following example illustrates the mapping relationship between the ambient temperature and the standard temperature curve set corresponding to multiple characteristic test items:

[0068] For example, the characteristic test item is capacity testing, the number of temperature sensors is 10, and the ambient temperatures are 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, and 45°C (it should be noted that the number of temperature sensors and the ambient temperature corresponding to the capacity test can also be set to other values ​​according to actual usage requirements, which will not be further elaborated here). In order to configure the mapping relationship between the ambient temperature corresponding to the capacity test and the set of standard temperature curves, a battery cell that has just been shipped from the factory can be used as the test object for capacity testing, and 10 temperature sensors can be set at different positions on the surface of the battery cell. The battery cell with the temperature sensor is placed in a place with an ambient temperature of 5°C, and the capacity test is started. During the capacity test, the temperatures detected by the 10 temperature sensors are recorded in real time. After completing the capacity test at an ambient temperature of 5°C, the temperature measured by each temperature sensor at each test time when the ambient temperature is 5°C is plotted as the standard temperature curve of the corresponding temperature sensor, with the test time as the horizontal axis and the temperature measured by the corresponding temperature sensor as the vertical axis. Similarly, capacity detection can be performed at ambient temperatures of 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, and 45°C, so that standard temperature curves corresponding to temperature sensors at other ambient temperatures can be obtained, and then a set of standard temperature curves corresponding to each ambient temperature can be obtained, thereby completing the pre-configuration of the mapping relationship between the ambient temperature and the set of standard temperature curves.

[0069] For example, the characteristic test item is internal resistance detection, the number of temperature sensors is 10, and the ambient temperatures are 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, and 45°C (it should be noted that the number of temperature sensors and the ambient temperature corresponding to the internal resistance detection can also be set to other values ​​according to actual usage requirements, which will not be further explained here). In order to configure the mapping relationship between the ambient temperature corresponding to the internal resistance detection and the set of standard temperature curves, a battery cell that has just been shipped can be used as the test object for internal resistance detection, and 10 temperature sensors can be set at different positions on the surface of the battery cell. The battery cell with the temperature sensors set is placed in a place with an ambient temperature of 5°C, and the internal resistance test is started. While the internal resistance test is being carried out, the temperatures detected by the 10 temperature sensors are recorded in real time. After completing the internal resistance test at an ambient temperature of 5°C, the temperature measured by each temperature sensor at each test time when the ambient temperature is 5°C is plotted as the standard temperature curve of the corresponding temperature sensor, with the test time as the horizontal axis and the temperature measured by the corresponding temperature sensor as the vertical axis. Similarly, internal resistance detection can be performed at ambient temperatures of 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, and 45°C, so that standard temperature curves corresponding to temperature sensors at other ambient temperatures can be obtained, and then a set of standard temperature curves corresponding to each ambient temperature can be obtained, thereby completing the pre-configuration of the mapping relationship between the ambient temperature corresponding to the internal resistance detection and the set of standard temperature curves.

[0070] For example, the characteristic test item is self-discharge rate detection, the number of temperature sensors is 10, and the ambient temperature is 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, and 45°C (it should be noted that the number of temperature sensors and the ambient temperature corresponding to the self-discharge rate detection can also be set to other values ​​according to actual usage requirements, which will not be further explained here). In order to configure the mapping relationship between the ambient temperature corresponding to the self-discharge rate detection and the standard temperature curve set, a battery cell that has just been shipped can be used as the test object for the self-discharge rate detection, and 10 temperature sensors are set at different positions on the surface of the battery cell. The battery cell with the temperature sensors is placed in a place with an ambient temperature of 5°C and the self-discharge rate detection is started. During the self-discharge rate detection, the temperatures detected by the 10 temperature sensors are recorded in real time. After completing the self-discharge rate test at an ambient temperature of 5°C, the temperature measured by each temperature sensor at each test time when the ambient temperature is 5°C is plotted as the standard temperature curve of the corresponding temperature sensor, with the test time as the horizontal axis and the temperature measured by the corresponding temperature sensor as the vertical axis. Similarly, self-discharge rate detection can be performed at ambient temperatures of 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, and 45°C, so that standard temperature curves of corresponding temperature sensors at other ambient temperatures can be obtained, and then a set of standard temperature curves corresponding to each ambient temperature can be obtained, that is, the pre-configuration of the mapping relationship between the ambient temperature corresponding to the self-discharge rate detection and the set of standard temperature curves is completed.

[0071] For example, the characteristic test item is open circuit voltage detection, the number of temperature sensors is 10, and the ambient temperatures are 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, and 45°C (it should be noted that the number of temperature sensors and the ambient temperature corresponding to the open circuit voltage detection can also be set to other values ​​according to actual usage requirements, which will not be further explained here). In order to configure the mapping relationship between the ambient temperature corresponding to the open circuit voltage detection and the set of standard temperature curves, a newly produced battery cell can be used as the test object for the open circuit voltage detection, and 10 temperature sensors can be set at different positions on the surface of the battery cell. The battery cell with the temperature sensors is placed in an environment with an ambient temperature of 5°C and the open circuit voltage detection is started. During the open circuit voltage detection, the temperatures detected by the 10 temperature sensors are recorded in real time. After completing the open circuit voltage detection at an ambient temperature of 5°C, the temperature measured by each temperature sensor at each test time when the ambient temperature is 5°C is plotted as the standard temperature curve of the corresponding temperature sensor, with the test time as the horizontal axis and the temperature measured by the corresponding temperature sensor as the vertical axis. Similarly, open circuit voltage detection can be performed at ambient temperatures of 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, and 45°C, so that standard temperature curves corresponding to temperature sensors at other ambient temperatures can be obtained, and then a set of standard temperature curves corresponding to each ambient temperature can be obtained, thereby completing the pre-configuration of the mapping relationship between the ambient temperature corresponding to the open circuit voltage detection and the set of standard temperature curves.

[0072] In one embodiment, the correction of the test results of the characteristic test items of the battery cell based on the N standard temperature curves and the temperature test curves of the N temperature sensors specifically includes:

[0073] Determine a test correction factor based on N standard temperature curves and temperature test curves of N temperature sensors;

[0074] Based on the mapping relationship between the pre-configured weights of the temperature sensors and the standard temperature curves, respectively determine the weights of the N temperature sensors corresponding to the N standard temperature curves;

[0075] Based on the test correction coefficient and the weight of the temperature sensor, the test results of the characteristic test items of the battery cell are corrected.

[0076] In this embodiment, taking into account that the degree of deviation between the temperature of the battery cells at different positions monitored in real time and the standard temperature during the test process may be different, respective weights are set for the temperature sensors at different positions to characterize the degree of influence of the temperature changes at different positions of different battery cells on the test results, and the test results of the characteristic test items of the battery cells are corrected based on the test correction coefficient and the weight of the temperature sensor, thereby achieving accurate screening.

[0077] Exemplarily, determining the test correction coefficient based on N standard temperature curves and temperature test curves of N temperature sensors specifically includes:

[0078] For each temperature test curve, the test correction coefficient is calculated using the following formula:

[0079]

[0080] Among them, t represents different test moments, t∈{1, 2,…, t s}; i represents the serial number of different sensors and the serial number of different standard temperature curves, i∈{1, 2, ..., N}; x i is the test correction coefficient corresponding to the i-th temperature test curve; t s T is the total test time of the current feature test item; it is the temperature value of the ith temperature test curve at time t; T bt is the temperature value of the i-th standard temperature curve at the t-th moment.

[0081] Exemplarily, the correction of the test results of the characteristic test items of the battery cell based on the test correction coefficient and the weight of the temperature sensor specifically includes:

[0082] The test results of the battery cell characteristic test items are corrected using the following formula:

[0083]

[0084] Wherein, Y is the test result of the characteristic test item of the battery cell, and Z is the test result of the characteristic test item of the battery cell after correction; q i is the weight of the i-th temperature sensor.

[0085] Accordingly, an embodiment of the present invention also provides a device for screening retired power batteries for recycling. Figure 2 , which is a structural block diagram of a retired power battery recycling screening device in an embodiment of the present invention.

[0086] The retired power battery recycling screening device according to an embodiment of the present invention includes:

[0087] The appearance screening module 10 is used to perform appearance screening on battery cells, wherein the battery cells are removed from retired power batteries;

[0088] The voltage detection module 20 is used to perform voltage detection on battery cells that have passed the appearance screening;

[0089] The test module 30 is used to perform multiple characteristic test operations on battery cells that have passed the voltage test under different ambient temperatures;

[0090] The classification module 40 is used to classify and reorganize the battery cells based on the test results of multiple characteristic test items.

[0091] In one embodiment, the test operation method for each characteristic test item in the test operation of the plurality of characteristic test items is as follows:

[0092] According to the preset installation rules, N temperature sensors are respectively installed at different positions of the battery cells;

[0093] determining a standard temperature curve set corresponding to the current ambient temperature based on a pre-configured mapping relationship between the ambient temperature and the standard temperature curve set; wherein the standard temperature curve set includes N standard temperature curves, each of the N standard temperature curves corresponding one-to-one to N temperature sensors disposed at different locations of the battery cell according to the preset installation rule, and each standard temperature curve is a curve formed based on temperature data collected at different times by the corresponding temperature sensor when the battery cell is tested in a factory state according to the preset characteristic test rule;

[0094] When testing the characteristic test items of battery cells, the temperature test curves of N temperature sensors are recorded in real time;

[0095] Based on N standard temperature curves and temperature test curves of N temperature sensors, test results of characteristic test items of the battery cell are corrected.

[0096] In one embodiment, the correction of the test results of the characteristic test items of the battery cell based on the N standard temperature curves and the temperature test curves of the N temperature sensors specifically includes:

[0097] Determine a test correction factor based on N standard temperature curves and temperature test curves of N temperature sensors;

[0098] Based on the mapping relationship between the pre-configured weights of the temperature sensors and the standard temperature curves, respectively determine the weights of the N temperature sensors corresponding to the N standard temperature curves;

[0099] Based on the test correction coefficient and the weight of the temperature sensor, the test results of the characteristic test items of the battery cell are corrected.

[0100] In one embodiment, determining the test correction coefficient based on the N standard temperature curves and the temperature test curves of the N temperature sensors specifically includes:

[0101] For each temperature test curve, the test correction coefficient is calculated using the following formula:

[0102]

[0103] Among them, t represents different test moments, t∈{1, 2,…, t s}; i represents the serial number of different sensors and the serial number of different standard temperature curves, i∈{1, 2, ..., N}; x i is the test correction coefficient corresponding to the i-th temperature test curve; t s T is the total test time of the current feature test item; it is the temperature value of the ith temperature test curve at time t; T bt is the temperature value of the i-th standard temperature curve at the t-th moment.

[0104] In one embodiment, the correction of the test results of the characteristic test items of the battery cell based on the test correction coefficient and the weight of the temperature sensor specifically includes:

[0105] The test results of the battery cell characteristic test items are corrected using the following formula:

[0106]

[0107] Wherein, Y is the test result of the characteristic test item of the battery cell, and Z is the test result of the characteristic test item of the battery cell after correction; q i is the weight of the i-th temperature sensor.

[0108] In one embodiment, the characteristic test items include at least one of capacity detection, internal resistance detection, self-discharge rate detection and open circuit voltage detection.

[0109] In one embodiment, the appearance screening module is specifically configured to:

[0110] Check whether the battery cells are damaged or the electrolyte is leaking;

[0111] When electrolyte leakage is detected in a battery cell, the battery cell currently being measured will be scrapped;

[0112] When a battery cell is detected to be damaged but no electrolyte leakage occurs, the currently measured battery cell is recycled and reused;

[0113] When no damage or electrolyte leakage is detected in the battery cell, the currently measured battery cell size is compared with the pre-stored corresponding battery cell size information. If the deformation of the battery cell exceeds the preset deformation threshold, the currently measured battery cell is recycled and reused.

[0114] It should be noted that the retired power battery cascade utilization screening device provided in an embodiment of the present invention is used to execute all the process steps of the retired power battery cascade utilization screening method of the above embodiment. The working principles and beneficial effects of the two correspond one to one, and therefore will not be repeated here.

[0115] It should be noted that the device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed across multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the present embodiment. In addition, in the drawings of the device embodiments provided by the present invention, the connection relationship between the modules indicates that there is a communication connection between them, which may be specifically implemented as one or more communication buses or signal lines. A person of ordinary skill in the art can understand and implement the present invention without inventive effort.

[0116] Compared with the prior art, the beneficial effects of the embodiments of the present invention are as follows: the embodiments of the present invention provide a method and device for screening retired power batteries for cascade utilization, by performing appearance screening on battery cells; wherein, the battery cells are removed from the retired power batteries, and voltage detection is performed on the battery cells that have passed the appearance screening, and multiple characteristic test items are tested on the battery cells that have passed the voltage detection at different ambient temperatures. Based on the test results of the multiple characteristic test items, the battery cells are classified and reorganized. In this way, by performing multiple characteristic test items on the battery cells at different ambient temperatures, the battery status data under the influence of different ambient temperatures can be reflected, thereby achieving accurate screening.

[0117] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A method for screening retired power batteries for cascade utilization, characterized in that: include: Performing appearance screening on battery cells; wherein the battery cells are removed from retired power batteries; Conduct voltage testing on battery cells that have passed the appearance screening; Under different ambient temperatures, multiple characteristic test items are tested on battery cells that have passed the voltage test; Classify and reorganize battery cells based on the test results of multiple characteristic test items; The test operation method of each characteristic test item in the test operation of the multiple characteristic test items is as follows: According to the preset installation rules, N temperature sensors are respectively installed at different positions of the battery cells; determining a standard temperature curve set corresponding to the current ambient temperature based on a pre-configured mapping relationship between the ambient temperature and the standard temperature curve set; wherein the standard temperature curve set includes N standard temperature curves, each of the N standard temperature curves corresponding one-to-one to N temperature sensors disposed at different locations of the battery cell according to the preset installation rule, and each standard temperature curve is a curve formed based on temperature data collected at different times by the corresponding temperature sensor when the battery cell is tested in a factory state according to the preset characteristic test rule; When testing the characteristic test items of battery cells, the temperature test curves of N temperature sensors are recorded in real time; Based on N standard temperature curves and temperature test curves of N temperature sensors, test results of characteristic test items of the battery cell are corrected.

2. The method for screening retired power batteries for cascade utilization according to claim 1, characterized in that: The method of correcting the test results of the characteristic test items of the battery cell based on the N standard temperature curves and the temperature test curves of the N temperature sensors specifically includes: Determine a test correction factor based on N standard temperature curves and temperature test curves of N temperature sensors; Based on the mapping relationship between the pre-configured weights of the temperature sensors and the standard temperature curves, respectively determine the weights of the N temperature sensors corresponding to the N standard temperature curves; Based on the test correction coefficient and the weight of the temperature sensor, the test results of the characteristic test items of the battery cell are corrected.

3. The method for screening retired power batteries for cascade utilization according to claim 2, characterized in that: The determining of the test correction coefficient based on the N standard temperature curves and the temperature test curves of the N temperature sensors specifically includes: For each temperature test curve, the test correction coefficient is calculated using the following formula: Among them, t represents different test moments, t∈{1, 2,…, t s }; i represents the serial number of different sensors and the serial number of different standard temperature curves, i∈{1, 2, ..., N}; x i is the test correction coefficient corresponding to the i-th temperature test curve; t s T is the total test time of the current feature test item; it is the temperature value of the ith temperature test curve at time t; T bt is the temperature value of the i-th standard temperature curve at the t-th moment.

4. The method for screening retired power batteries for cascade utilization according to claim 3, characterized in that: The test results of the characteristic test items of the battery cell are corrected based on the test correction coefficient and the weight of the temperature sensor, specifically including: The test results of the battery cell characteristic test items are corrected using the following formula: Wherein, Y is the test result of the characteristic test item of the battery cell, and Z is the test result of the characteristic test item of the battery cell after correction; q i is the weight of the i-th temperature sensor.

5. The method for screening retired power batteries for cascade utilization according to any one of claims 1 to 4, characterized in that: The plurality of characteristic test items include at least one of capacity detection, internal resistance detection, self-discharge rate detection and open circuit voltage detection.

6. The method for screening retired power batteries for cascade utilization according to any one of claims 1 to 4, characterized in that: The appearance screening of the battery cells specifically includes: Check whether the battery cells are damaged or the electrolyte is leaking; When electrolyte leakage is detected in a battery cell, the battery cell currently being measured will be scrapped; When a battery cell is detected to be damaged but no electrolyte leakage occurs, the currently measured battery cell is recycled and reused; When no damage or electrolyte leakage is detected in the battery cell, the currently measured battery cell size is compared with the pre-stored corresponding battery cell size information. If the deformation of the battery cell exceeds the preset deformation threshold, the currently measured battery cell is recycled and reused.

7. A retired power battery cascade utilization screening device, characterized in that: include: An appearance screening module, used to perform appearance screening on battery cells; wherein the battery cells are removed from retired power batteries; Voltage detection module, used to perform voltage detection on battery cells that have passed the appearance screening; The test module is used to perform multiple characteristic test operations on battery cells that have passed the voltage test at different ambient temperatures; A classification module is used to classify and reorganize battery cells based on the test results of multiple characteristic test items; The test operation method of each characteristic test item in the test operation of the multiple characteristic test items is as follows: According to the preset installation rules, N temperature sensors are respectively installed at different positions of the battery cells; determining a standard temperature curve set corresponding to the current ambient temperature based on a pre-configured mapping relationship between the ambient temperature and the standard temperature curve set; wherein the standard temperature curve set includes N standard temperature curves, each of the N standard temperature curves corresponding one-to-one to N temperature sensors disposed at different locations of the battery cell according to the preset installation rule, and each standard temperature curve is a curve formed based on temperature data collected at different times by the corresponding temperature sensor when the battery cell is tested in a factory state according to the preset characteristic test rule; When testing the characteristic test items of battery cells, the temperature test curves of N temperature sensors are recorded in real time; Based on N standard temperature curves and temperature test curves of N temperature sensors, test results of characteristic test items of the battery cell are corrected.

8. The retired power battery recycling screening device according to claim 7, characterized in that: The plurality of characteristic test items include at least one of capacity detection, internal resistance detection, self-discharge rate detection and open circuit voltage detection.

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