Battery screening method, electronic equipment and storage medium

Abstract

The invention discloses a battery screening method, electronic equipment and a storage medium. The battery screening method comprises the following steps: acquiring first voltages of a plurality of to-be-detected batteries after first standing from a preset electric quantity; obtaining a second voltage of the plurality of to-be-tested batteries after the plurality of to-be-tested batteries are subjected to pressurization treatment according to a preset pressurization parameter and then subjected to second standing; based on the first voltage, the second voltage and a preset pressurization parameter, the self-discharge rate of each to-be-tested battery is obtained; and determining a qualified battery in the plurality of batteries to be detected based on the self-discharge rate.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to battery screening methods, electronic devices, and storage media. Background Technology

[0002] In lithium-ion battery manufacturing, the K-value is a key indicator for screening defective cells. The K-value refers to the rate at which the battery voltage drops per unit time, and is used to measure its self-discharge performance. It can also be expressed as self-discharge rate or voltage decay rate.

[0003] Existing methods typically involve observing the voltage drop of batteries and screening them by either allowing them to stand at room temperature or conducting segmented high and low temperature tests. However, these methods lack sufficient sensitivity to testing cycles and have a low detection rate for defects induced by metallic foreign objects, resulting in low accuracy in battery screening. Summary of the Invention

[0004] A battery screening method is provided to improve the accuracy of battery cell screening.

[0005] Firstly, a battery screening method is provided, comprising the following steps: Acquire the first voltage of multiple batteries under test after a first rest period starting from a preset charge level; After obtaining multiple batteries to be tested and pressurizing them according to preset pressurization parameters, the second voltage is obtained after a second settling period. Based on the first voltage, the second voltage, and the preset pressure parameters, the self-discharge rate of each battery under test is obtained; Based on the self-discharge rate, qualified batteries were identified from a group of batteries to be tested.

[0006] In one embodiment, obtaining the second voltage of multiple batteries under test after being pressurized according to preset pressurization parameters and then subjected to a second settling period includes: Place multiple batteries to be tested into a pre-pressurized container; Using a pressure source, multiple batteries under test in a preset pressure container are pressurized according to preset pressure parameters; The second voltage of multiple batteries under test is measured after they have been pressurized and then allowed to stand for a second time.

[0007] In this embodiment, the battery under test is placed in a preset pressurized container and pressurized. By applying external force, the electrode spacing of the battery under test can be compressed, thereby increasing the self-discharge abnormality of the battery under test and improving the accuracy of battery anomaly detection.

[0008] In one embodiment, the battery screening method further includes: Obtain the measurement time points of the first voltage corresponding to multiple batteries under test; Multiple batteries under test are divided based on measurement time points to obtain multiple battery packs under test; After obtaining the second voltage of multiple batteries under test after being pressurized according to preset pressurization parameters and then subjected to a second settling period, the voltage includes: After pressurizing multiple battery packs under test according to preset pressurization parameters, a second settling period is performed to obtain the second voltage of multiple batteries under test in each battery pack after the second settling period.

[0009] In this embodiment, by dividing multiple batteries under test into test battery groups, the consistency of the first voltage of the batteries under test in each test battery group can be ensured, thereby calculating the self-discharge rate based on the first voltage and the second voltage of the test battery group, which improves the accuracy of the self-discharge rate of each battery under test.

[0010] In one embodiment, multiple batteries under test are divided based on measurement time points to obtain multiple battery packs under test, including: The target measurement range is determined based on the preset self-discharge rate threshold range and the reference self-discharge rate dispersion. Based on the target measurement interval and measurement time point, multiple batteries to be tested are divided to obtain multiple battery packs to be tested.

[0011] In this embodiment, by determining the target measurement interval based on the preset self-discharge rate threshold interval and the reference self-discharge rate dispersion, the voltage consistency of the battery pack under test divided according to the target measurement interval can be guaranteed, thereby ensuring the accuracy of the self-discharge rate of the battery under test.

[0012] In one embodiment, multiple batteries under test are divided based on measurement time points to obtain multiple battery packs under test, including: Based on the measurement time points, calculate the voltage difference between the first voltage corresponding to the first measurement time point and the first voltage corresponding to multiple other measurement time points; Batteries under test whose voltage difference is less than a preset voltage difference threshold are grouped into a single battery group. For the remaining undivided batteries to be tested, return to the step of calculating the voltage difference between the first voltage corresponding to the first measurement time point and the first voltage corresponding to multiple other measurement time points, based on the measurement time point, until multiple battery packs to be tested are obtained.

[0013] In this embodiment, by dividing the battery into multiple test battery groups based on the voltage difference between the test batteries, it is possible to ensure that the voltage difference between the test batteries in the test battery group is less than a preset threshold, thereby ensuring the consistency of the first voltage of the test battery group and improving the accuracy of the self-discharge rate of the test battery.

[0014] In one embodiment, determining the qualified battery among a plurality of batteries under test based on self-discharge rate includes: For any number of batteries under test in a battery pack under test, sort the self-discharge rates of the batteries under test to obtain a self-discharge rate sequence. Based on the self-discharge rate sequence, the target self-discharge rate threshold range is determined; Based on the target self-discharge rate threshold range and the self-discharge rate of multiple current test batteries, multiple test batteries are screened to obtain qualified batteries, thus obtaining qualified batteries among multiple test batteries.

[0015] In this embodiment, by determining the corresponding target self-discharge rate threshold range based on the self-discharge rate of the batteries under test in different battery packs, and then screening qualified batteries for the corresponding battery packs under test according to the target self-discharge rate threshold range, the accuracy of screening qualified batteries can be guaranteed.

[0016] In one embodiment, the first voltage is obtained by subjecting multiple test batteries to a first static condition under both high-temperature and normal-temperature environments until the voltage change of the multiple test batteries under normal-temperature environment is less than a preset threshold value; the high-temperature environment is 40°C to 50°C; and / or, The second voltage is obtained by subjecting multiple test batteries to a second settling period at room temperature until the voltage change of the multiple test batteries at room temperature is less than or equal to the reference voltage change.

[0017] In this embodiment, by subjecting multiple batteries to test to a first settling period under both high-temperature and normal-temperature conditions, the internal chemical reaction of the batteries to test can be accelerated, the voltage of the batteries to test can be stabilized more quickly, and the accuracy of the first voltage measured after the first settling period can be ensured.

[0018] In one embodiment, the battery under test is a pouch cell, the preset pressurization container is a preset sealed container, and the pressurization source is gas; and / or, The preset pressurization parameters include positive pressure value and positive pressure duration. The positive pressure value is 0.4 MPa to 0.8 MPa, and the positive pressure duration is 4 h to 8 h.

[0019] In this embodiment, by using positive pressure to detect the abnormal self-discharge rate of the battery caused by internal foreign matter, the accuracy of battery screening can be improved.

[0020] Secondly, this application also provides a battery sorting device, which includes: The first voltage acquisition module is used to acquire the first voltage of multiple batteries under test after a first resting period starting from a preset charge level. The second voltage acquisition module is used to acquire the second voltage of multiple batteries under test after they have been pressurized according to preset pressurization parameters and then subjected to a second settling period. The self-discharge rate calculation module is used to obtain the self-discharge rate of each battery under test based on the first voltage, the second voltage, and the preset pressure parameters. The battery screening module is used to identify qualified batteries from a group of batteries to be tested based on their self-discharge rate.

[0021] Thirdly, this application also provides an electronic device, including a memory and a processor, the memory storing a computer program for controlling the processor to operate in order to perform the methods in any of the embodiments of any of the above aspects.

[0022] Fourthly, this application also provides a computer-readable storage medium including computer instructions that, when executed by a processor, implement the methods in any of the embodiments described above.

[0023] Fifthly, the present application provides a computer program product that, when executed by a processor, implements the method in any of the above-described embodiments.

[0024] Beneficial Effects: This application obtains the first voltage of the battery under test after a first settling period, ensuring the accuracy of the first voltage. Then, after pressurizing the battery according to preset pressure parameters and followed by a second settling period, the second voltage is obtained. This pressurization process simulates internal battery stress, effectively amplifying abnormal voltage changes caused by potential defects such as micro-metallic foreign matter defects, shortening the detection cycle, and improving the measurement efficiency of the second voltage. Based on the first voltage, the second voltage, and the preset pressure parameters, the self-discharge rate of each battery under test is obtained, ensuring the accuracy of the battery self-discharge rate. Therefore, based on the self-discharge rate, qualified batteries are accurately screened, improving the detection rate and accuracy of qualified batteries. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic flowchart of the battery screening method provided by an exemplary embodiment of this disclosure; Figure 2 This is a schematic diagram of battery pressurization processing provided by an exemplary embodiment of this disclosure; Figure 3 This is a schematic flowchart of the battery screening steps provided in an exemplary embodiment of this disclosure; Figure 4 This is a schematic diagram of the structure of the battery screening device provided in an exemplary embodiment of this disclosure; Figure 5 This is an internal schematic diagram of an electronic device provided by an exemplary embodiment of this disclosure. Detailed Implementation

[0027] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0028] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0029] This application provides a battery screening method, an electronic device, and a storage medium. The electronic device can be a server or a terminal, etc. In one embodiment, the terminal acquires the first voltage of multiple batteries to be tested after a first resting period starting from a preset charge level; the terminal acquires the second voltage of the multiple batteries to be tested after being pressurized according to preset pressurization parameters and then subjected to a second resting period; the terminal obtains the self-discharge rate of each battery to be tested based on the first voltage, the second voltage, and the preset pressurization parameters; the terminal determines the qualified batteries among the multiple batteries to be tested based on the self-discharge rate. The terminal can be, but is not limited to, a computer, a laptop, etc. The server can be an independent physical server, a server cluster or distributed system composed of multiple physical servers, or a cloud server providing basic cloud computing services such as cloud services, cloud databases, cloud computing, big data, and artificial intelligence platforms. The terminal and the server can be directly or indirectly connected via wired or wireless communication, which is not limited herein.

[0030] On the one hand, this embodiment provides a battery screening method, such as Figure 1 As shown, it includes the following steps: S101, acquire the first voltage of multiple batteries under test after a first rest period starting from a preset charge level; The preset charge level refers to the target charge level that the battery under test needs to reach. The first resting period is a resting operation used to obtain the first voltage of the battery under test. The first voltage refers to the battery voltage obtained before the pressurization process. The battery under test can be a pouch lithium battery.

[0031] For example, multiple batteries under test are pre-charged to a preset level. This preset level can be set according to the battery type, such as setting the preset level for lithium batteries to 15% SOC. Then, the batteries are subjected to a first settling period according to a preset aging condition, allowing them to undergo aging treatment. The voltage changes of the batteries are monitored during this first settling period until they stabilize, at which point the corresponding first voltage is obtained. The voltage change rate during the first settling period can be collected; when the voltage change rate is less than a preset threshold, it indicates that the voltage change of the battery is stabilizing, and the corresponding first voltage is measured at this point. The preset aging condition can refer to a preset ambient temperature, used to control the batteries under test during the first settling period. Generally, the preset ambient temperature can be at least one of room temperature, high temperature, etc.

[0032] S102, after multiple batteries under test are pressurized according to preset pressurization parameters, the second voltage is obtained after a second settling period.

[0033] The preset pressurization parameters refer to the settings for pressurizing the battery under test, such as the pressure value and pressurization duration. Generally, this can mean applying positive pressure to the battery under test, meaning applying pressure higher than the local atmospheric pressure. The second resting period refers to the resting operation of the battery under test after pressurization, used to obtain the second voltage of the battery under test. The second voltage is the battery voltage collected after pressurization and the second resting period.

[0034] For example, pressurizing multiple batteries under test according to preset pressurization parameters can be achieved by setting a preset pressurization container according to the preset pressurization parameters, then placing the multiple batteries under test in the preset pressurization container, and pressurizing the multiple batteries under test through the preset pressurization container.

[0035] After a preset pressurization time, multiple batteries under test are transferred from the preset pressurization container to the outside for a second settling period. The voltage changes of these batteries are monitored during this second settling period until the voltage changes of the batteries tend to stabilize. At this point, the second voltage corresponding to each battery is obtained. This second settling can be performed at room temperature, and the voltage changes during this period are monitored. When the voltage change is less than or equal to a preset voltage change threshold, it indicates that the voltage changes of the batteries under test have tended to stabilize, and the second voltage corresponding to the batteries is measured at this point.

[0036] In one embodiment, the container capacity corresponding to the preset pressurized container is obtained, which represents the maximum number of batteries that can be accommodated in the preset pressurized container. When the number of batteries in multiple test batteries is greater than the container capacity, the multiple test batteries are divided into multiple test battery groups.

[0037] After obtaining the first voltage of the battery under test in multiple battery packs, the multiple batteries under test in each battery pack are placed in a preset pressurized container for pressurization, and then subjected to a second settling. The second voltage of the multiple batteries under test in each battery pack after the second settling is obtained. For example, the multiple batteries under test in battery pack A are pressurized and the second voltage after the second settling is obtained.

[0038] S103, based on the first voltage, the second voltage and the preset pressure parameters, obtains the self-discharge rate of each battery under test.

[0039] The self-discharge rate refers to the rate at which the battery's voltage drops per unit time, used to measure its self-discharge performance, and can be simply referred to as the "K-value". Generally speaking, when the battery's self-discharge rate is lower than or equal to the set acceptable threshold, it indicates that its self-discharge rate is within the normal range and there are no serious micro-short circuits or defects inside. However, when the battery's K-value is higher than the set acceptable threshold, it indicates that its self-discharge rate is too high and there may be defects such as metal foreign objects, impurities, or dendrites inside. This can lead to rapid loss of battery power during storage, shortened lifespan, and even safety risks.

[0040] For example, the preset pressurization parameters include the pressurization duration. The terminal acquires the first voltage and the second voltage corresponding to each of the multiple batteries under test, calculates the voltage difference between the first voltage and the second voltage of each battery under test, and then obtains the self-discharge rate corresponding to each battery under test based on the ratio of the voltage difference to the pressurization duration, thereby obtaining the self-discharge rate corresponding to each of the multiple batteries under test. The self-discharge rate corresponding to each of the multiple batteries under test can be the self-discharge rate under a preset pressure value or normal pressure.

[0041] S104, based on self-discharge rate, determines the qualified battery among multiple test batteries.

[0042] Among them, a qualified battery refers to a battery whose self-discharge rate meets the preset requirements.

[0043] For example, after obtaining the self-discharge rates of multiple batteries under test, the terminal filters the batteries based on their self-discharge rates to obtain qualified batteries. Specifically, the self-discharge rates of the multiple batteries under test can be compared with a preset self-discharge rate threshold, and batteries with self-discharge rates lower than the preset self-discharge rate threshold are identified as qualified batteries.

[0044] In one embodiment, after dividing multiple batteries under test into multiple battery packs and obtaining the self-discharge rate of multiple batteries under test in each battery pack, a target self-discharge rate threshold can be determined for each battery pack based on its respective self-discharge rate. This yields the target self-discharge rate thresholds for each of the multiple battery packs. The batteries under test in the corresponding battery packs are then screened according to the target self-discharge rate thresholds to obtain qualified batteries from the multiple battery packs.

[0045] In this embodiment, by acquiring the first voltage of the battery under test after the first settling period, the accuracy of the first voltage under static conditions can be ensured. Then, the second voltage of the battery under test after being pressurized according to preset pressurization parameters and then subjected to a second settling period is obtained. This pressurization process simulates internal battery stress, effectively amplifying abnormal voltage changes caused by potential defects, such as micro-metallic foreign matter defects, and shortening the detection cycle, thus improving the measurement efficiency of the second voltage. Based on the first voltage, the second voltage, and the preset pressurization parameters, the self-discharge rate of each battery under test is obtained, ensuring the accuracy of the battery self-discharge rate. Therefore, based on the self-discharge rate, qualified batteries are accurately screened from the test batteries, improving the detection rate and accuracy of qualified batteries.

[0046] In one embodiment, S102, obtaining the second voltage of multiple batteries under test after being pressurized according to preset pressurization parameters and then subjected to a second settling period, includes: Place multiple batteries to be tested into a pre-pressurized container; Using a pressure source, multiple batteries under test in a preset pressure container are pressurized according to preset pressure parameters; The second voltage of multiple batteries under test is measured after they have been pressurized and then allowed to stand for a second time.

[0047] The pre-pressurized container is a container used to provide a pressurized environment for pressurizing the battery under test.

[0048] For example, when the number of batteries under test is less than or equal to the capacity of the preset pressurization container, the batteries under test are placed into the preset pressurization container, and the multiple batteries under test in the preset pressurization container are pressurized by a pressurization source according to preset pressurization parameters, and the second voltage of the multiple batteries under test after pressurization and then after a second settling period is measured.

[0049] For example, such as Figure 2 The diagram shown illustrates the battery pressurization process. The battery under test can be a pouch cell. The battery is placed inside a pre-pressurized container, which can be a canister container, and the pressure stability of the cavity is less than the set pressure. 5%. Using gas as a positive pressure source, nitrogen or other compressed gas is injected into the container until the set positive pressure value is reached. The injected gas then comprehensively compresses all parts of the battery under test within the chamber (e.g., ...). Figure 2 The middle arrow points to the battery under test, and the pressure on the battery under test is uniform.

[0050] In this embodiment, the battery under test is placed in a preset pressurized container and pressurized. By applying external force, the electrode spacing of the battery under test can be compressed, thereby increasing the self-discharge abnormality of the battery under test and improving the accuracy of battery anomaly detection.

[0051] In one embodiment, such as Figure 3 As shown, the battery screening method also includes: S301, acquire the measurement time points of the first voltage corresponding to the multiple batteries under test; S302, based on the measurement time point, divide multiple batteries under test to obtain multiple battery packs under test; S102, acquire the second voltage of multiple batteries under test after being pressurized according to preset pressurization parameters and then subjected to a second settling period, including: After pressurizing multiple battery packs under test according to preset pressurization parameters, a second settling period is performed to obtain the second voltage of multiple batteries under test in each battery pack after the second settling period.

[0052] In the process of measuring the first voltage of multiple batteries under test, slow self-discharge constantly occurs within the batteries. If the interval between the measurement times of the first and last batteries is too long, a significant difference will occur between the first voltages of the first and last batteries, resulting in poor consistency of the first voltages across the multiple batteries under test. Therefore, the batteries under test can be grouped to ensure the consistency of the first voltages within the same group.

[0053] For example, after obtaining the first voltage corresponding to each of the multiple batteries under test, the terminal acquires the measurement time points corresponding to each of the first voltages. Based on these measurement time points, the multiple batteries under test are divided. Specifically, this can involve acquiring a target measurement interval corresponding to each battery under test. The target measurement interval can be a time window determined based on the dispersion of the self-discharge rate of multiple batteries of the same type under test. Then, the multiple measurement time points are divided according to the target measurement interval to obtain multiple battery packs under test. Alternatively, based on the measurement time points corresponding to each of the multiple batteries under test, a first voltage sequence corresponding to the multiple batteries under test is determined. Within this first voltage sequence, the voltage difference between each battery under test and other batteries under test is calculated sequentially. The first voltage sequence is then divided based on the voltage differences to obtain multiple battery packs under test. In each battery pack under test, the number of batteries is less than the capacity of a preset pressurized container.

[0054] Then, multiple batteries under test from multiple test groups are placed into a preset pressurized container for pressurization, and the second voltage of multiple batteries under test is obtained after a second settling period.

[0055] In this embodiment, by dividing multiple batteries under test into test battery groups, the consistency of the first voltage of the batteries under test in each test battery group can be ensured, thereby calculating the self-discharge rate based on the first voltage and the second voltage of the test battery group, which improves the accuracy of the self-discharge rate of each battery under test.

[0056] In one embodiment, multiple batteries under test are divided based on measurement time points to obtain multiple battery packs under test, including: The target measurement range is determined based on the preset self-discharge rate threshold range and the reference self-discharge rate dispersion. Based on the target measurement interval and measurement time point, multiple batteries to be tested are divided to obtain multiple battery packs to be tested.

[0057] The sample battery and the battery under test are of the same battery type, such as a pouch lithium battery. The target measurement time point is a time window used to select measurement time points. The reference self-discharge rate dispersion is the dispersion obtained based on the self-discharge rate of the sample battery and can be used as reference data for the self-discharge rate dispersion of the battery under test.

[0058] For example, after obtaining the first voltage corresponding to each of the multiple batteries under test, the terminal acquires a preset self-discharge rate threshold range and a reference self-discharge rate dispersion for each battery under test. The preset self-discharge rate threshold range can be obtained based on the difference between a preset upper limit and a preset lower limit for self-discharge rate. The reference self-discharge rate dispersion can be obtained by calculating the standard deviation of the self-discharge rates of multiple sample batteries.

[0059] Then, the target measurement interval is obtained by calculating the ratio of the preset self-discharge rate threshold interval to the reference self-discharge rate dispersion, as shown in formula (1).

[0060] m = (Upper standard limit of K value - Lower standard limit of K value) / Standard deviation of K value (1) Where m represents the target measurement interval, in h (hours); the upper limit of the K-value standard represents the upper limit of the self-discharge rate; the lower limit of the K-value standard represents the lower limit of the self-discharge rate; the standard deviation of the K-value represents the dispersion of the reference self-discharge rate; (upper limit of the K-value standard - lower limit of the K-value standard) represents the preset self-discharge rate threshold interval.

[0061] Then, based on the measurement time points, multiple batteries to be tested are sorted to obtain a battery sequence. The battery sequence is then divided according to the target measurement interval to obtain multiple battery groups. In each battery group, the interval between the measurement time points of the first and last battery is less than or equal to the time length corresponding to the target measurement interval. The target measurement interval can be understood as the average time (e.g., m hours) required for a qualified battery to naturally drop its voltage beyond the acceptable range (from the upper limit of self-discharge rate to the lower limit of self-discharge rate).

[0062] In this embodiment, by determining the target measurement interval based on the preset self-discharge rate threshold interval and the reference self-discharge rate dispersion, the voltage consistency of the battery pack under test divided according to the target measurement interval can be guaranteed, thereby ensuring the accuracy of the self-discharge rate of the battery under test.

[0063] In one embodiment, multiple batteries under test are divided based on measurement time points to obtain multiple battery packs under test, including: Based on the measurement time points, calculate the voltage difference between the first voltage corresponding to the first measurement time point and the first voltage corresponding to multiple other measurement time points; Batteries under test whose voltage difference is less than a preset voltage difference threshold are grouped into a single battery group. For the remaining undivided batteries to be tested, return to the step of calculating the voltage difference between the first voltage corresponding to the first measurement time point and the first voltage corresponding to multiple other measurement time points, based on the measurement time point, until multiple battery packs to be tested are obtained.

[0064] For example, the terminal sorts the first voltages corresponding to the multiple batteries under test according to the measurement time points corresponding to each battery under test, thus obtaining a first voltage sequence. In the first voltage sequence, the voltage difference between the first voltage corresponding to the first measurement time point and the first voltages corresponding to multiple other measurement time points is used to classify the batteries under test whose voltage difference is less than a preset voltage difference threshold into a battery group under test. Then, multiple batteries under test in the battery group under test are deleted from the first voltage sequence to obtain an updated first voltage sequence.

[0065] Then, update the first voltage sequence as the first voltage sequence, and return to the steps for the remaining undivided multiple test batteries. For the remaining undivided multiple test batteries, return to the steps of calculating the voltage difference between the first voltage corresponding to the first measurement time point and the first voltage corresponding to multiple other measurement time points in the first voltage sequence, until multiple test battery packs are obtained.

[0066] In this embodiment, by dividing the battery into multiple test battery groups based on the voltage difference between the test batteries, it is possible to ensure that the voltage difference of the test batteries in the test battery group is less than a preset threshold, thereby ensuring the consistency of the first voltage of the test battery group and improving the accuracy of the self-discharge rate of the test battery.

[0067] In one embodiment, determining the qualified battery among a plurality of batteries under test based on self-discharge rate includes: For any number of batteries under test in a battery pack under test, sort the self-discharge rates of the batteries under test to obtain a self-discharge rate sequence. Based on the self-discharge rate sequence, the target self-discharge rate threshold range is determined; Based on the target self-discharge rate threshold range and the self-discharge rate of multiple current test batteries, multiple test batteries are screened to obtain qualified batteries, thus obtaining qualified batteries among multiple test batteries.

[0068] For example, after obtaining the self-discharge rate of multiple batteries in each battery pack under test, the terminal sorts the self-discharge rates of multiple current batteries under test in any battery pack under test to obtain a self-discharge rate sequence.

[0069] According to a preset number of preset quantile parameters, a preset number of feature values ​​are extracted from the self-discharge rate sequence. Specifically, based on the self-discharge rate and the preset quantile parameters, the percentile of the feature value in the self-discharge rate sequence is determined, and then the self-discharge rate corresponding to that percentile is obtained as the feature value in the self-discharge rate sequence.

[0070] Percentile calculation is shown in formula (2).

[0071] Percentile = (n+1) × X% (2) Where n represents the number of self-discharge rates in the self-discharge rate sequence; X% represents the preset quantile parameter.

[0072] The preset quantile parameters include 25%, 50%, and 75%. The number of self-discharge rates in the self-discharge rate sequence is 15. Based on the number of self-discharge rates and the preset quantile parameters, the percentile of the feature value in the self-discharge rate sequence is determined. For example, the 25th percentile = (15+1) × 0.25 = 4. Then, the 4th self-discharge rate in the self-discharge rate sequence is extracted as the feature value.

[0073] Then, based on multiple feature values, the target self-discharge rate threshold range is determined. For example, if the preset quantile parameters 25%, 50%, and 75% correspond to feature values ​​Q1, Q2, and Q3 respectively, the target self-discharge rate threshold range is (Q1-a). IQR, Q3+ IQR). Where 'a' represents a preset parameter with a value range of 1.5 ≤ a ≤ 3, used to calculate the target self-discharge rate threshold range, and IQR represents the difference between the characteristic value Q3 and the characteristic value Q1, i.e., IQR = Q3 - Q1.

[0074] Then, based on the target self-discharge rate threshold range, multiple batteries in the battery pack under test are screened. For example, batteries in the battery pack under test whose self-discharge rate is within the target self-discharge rate threshold range are identified as qualified batteries in the battery pack under test, thus obtaining qualified batteries from multiple batteries under test.

[0075] In this embodiment, by determining the corresponding target self-discharge rate threshold range based on the self-discharge rate of the batteries under test in different battery packs, and then screening qualified batteries for the corresponding battery packs under test according to the target self-discharge rate threshold range, the accuracy of screening qualified batteries can be guaranteed.

[0076] In one embodiment, the first voltage is obtained by subjecting multiple test batteries to a first static condition under both high-temperature and normal-temperature environments until the voltage change of the multiple test batteries under normal-temperature environment is less than a preset threshold value; the high-temperature environment is 40°C to 50°C; and, The second voltage is obtained by subjecting multiple test batteries to a second settling period at room temperature until the voltage change of the multiple test batteries at room temperature is less than or equal to the reference voltage change.

[0077] For example, when performing the first settling aging treatment on the battery under test, one of the following can be used: high-temperature settling, room-temperature settling, or a combination of high-temperature and room-temperature settling. Generally, a combination of high-temperature and room-temperature settling is used, where multiple batteries under test are subjected to the first settling in both high-temperature and room-temperature environments, and the first voltage of the battery under test is obtained after the first settling.

[0078] The ambient temperature is 25℃, and the high temperature is 40℃~50℃. During the aging process of the batteries under test, multiple batteries are first placed in a high-temperature environment, then placed in a ambient temperature environment. The voltage change rate of the batteries is monitored at the ambient temperature. The optimal aging time, i.e., the first resting time, is determined when the voltage change rate is less than a preset threshold. For example, the first resting time could include 24~72h at high temperature and 12~48h at ambient temperature. Then, the first voltage of each battery is measured.

[0079] After the pressure treatment of the battery under test is completed, the multiple batteries under test are subjected to a second settling at room temperature, and the second voltage after the second settling is obtained.

[0080] In this process, during the resting period after the battery under test has finished pressurizing, the voltage change of the battery under test is monitored, and the resting time point after the voltage stabilizes is selected as the second resting time. For example, assume that the voltage change within hours a to b is greater than K1. (ba) indicates that the battery needs to be left unused for more than b hours. Assume that the voltage change within b hours to c hours is less than or equal to K1. (cb) indicates that the battery can be left to stand for c hours, meaning the second resting period is c hours. K1 represents the self-discharge rate of the battery under test at room temperature, which was measured in advance.

[0081] In this embodiment, by subjecting multiple batteries to test to a first settling period under both high-temperature and normal-temperature conditions, the internal chemical reaction of the batteries to test can be accelerated, the voltage of the batteries to test can be stabilized more quickly, and the accuracy of the first voltage measured after the first settling period can be ensured.

[0082] In one embodiment, the battery under test is a pouch cell, the preset pressurization container is a preset sealed container, and the pressurization source is gas; and / or, The preset pressurization parameters include pressure value and pressurization duration. The pressure value is 0.4 MPa to 0.8 MPa, and the pressurization duration is 4 hours to 8 hours.

[0083] For example, the battery under test is a pouch battery. Since the casing of a pouch battery is made of aluminum-plastic film, it does not have a strong constraint on the internal thickness of the battery and is deformable. The electrode spacing of the pouch battery can be compressed by applying external force, such as applying positive pressure to the pouch battery, in order to increase the detection rate of cells with abnormal self-discharge.

[0084] The pouch cells are placed in a pre-designed sealed container using a contouring fixture, such as... Figure 2The schematic diagram shows that the pressurization source is gas. Nitrogen or other compressed gas is filled into the positive pressure tank, so that the pressure stability inside the sealed container is less than the set pressure. 5%.

[0085] Then, the pouch battery is pressurized according to the preset pressure parameters. Specifically, this can be achieved by filling the container with gas to create positive pressure. Positive pressure means a pressure higher than the local atmospheric pressure. The preset pressure parameters include the positive pressure value and the duration of positive pressure treatment.

[0086] Generally, the higher the pressure value, the greater the voltage drop of the abnormal battery. This means the self-discharge rate of the abnormal battery is positively correlated with the pressure value, while the self-discharge rate of normal batteries is unaffected by the pressure value. Therefore, the higher the pressure value, the higher the detection rate of abnormal batteries. Considering both detection rate and safety, the pressure value is set to 0.4~0.8 MPa. Similarly, the longer the pressurization time, the greater the voltage drop of the abnormal battery. This means the self-discharge rate of the abnormal battery is positively correlated with the pressurization time, while the self-discharge rate of normal batteries is unaffected by the pressurization time. Therefore, the longer the pressurization time, the higher the detection rate of abnormal batteries. Considering both detection rate and production capacity, the pressurization time is set to 4h~8h.

[0087] In addition, reference values ​​can be set for pressure parameters, and the pressure value or pressurization time can be determined based on the reference values. For example, pressure value Pressurization time ≥2MPa h indicates that the time integral of the pressure during pressure testing or pressure maintenance is at least 2 MPa. h, that is, the cumulative pressure action is greater than or equal to 2 MPa h is used to ensure the effective detection of abnormal voltage decay (i.e., abnormal self-discharge rate) in abnormal batteries during pressurization. For example, if the pressure value is set to αMPa, the minimum pressurization time is 2MPa. h / αMPa, or setting the pressurization time to βh, then the minimum pressure value is 2MPa. h / βh.

[0088] In this embodiment, by using positive pressure to detect the abnormal self-discharge rate of the battery caused by internal foreign matter, the accuracy of battery screening can be improved.

[0089] On the other hand, this embodiment provides a battery screening device. Figure 4 This is a schematic diagram of a battery screening device according to an embodiment of this application, such as... Figure 4 As shown, the battery screening device 400 includes: a first voltage acquisition module 401, a second voltage acquisition module 402, a self-discharge rate calculation module 403, and a battery screening module 404. The device will be described below.

[0090] The first voltage acquisition module 401 is used to acquire the first voltage of multiple batteries under test after a first resting period starting from a preset charge level. The second voltage acquisition module 402 is used to acquire the second voltage of multiple batteries under test after being pressurized according to preset pressurization parameters and then subjected to a second settling period. The self-discharge rate calculation module 403 is used to obtain the self-discharge rate of each battery under test based on the first voltage, the second voltage and the preset pressure parameters. Battery screening module 404 is used to determine qualified batteries from a plurality of batteries to be tested based on self-discharge rate.

[0091] In one embodiment, the second voltage acquisition module 402 is further configured to place multiple batteries under test into a preset pressurization container; use a pressurization source to pressurize the multiple batteries under test in the preset pressurization container according to preset pressurization parameters; and measure the second voltage of the multiple batteries under test after pressurization and a second settling period.

[0092] In one embodiment, the second voltage acquisition module 402 is further configured to acquire the measurement time points of the first voltage corresponding to the multiple batteries under test; divide the multiple batteries under test based on the measurement time points to obtain multiple battery packs under test; after pressurizing the multiple battery packs under test according to preset pressurization parameters, and then after a second resting period, acquire the second voltage of the multiple batteries under test in each battery pack under test after the second resting period.

[0093] In one embodiment, the second voltage acquisition module 402 is further configured to determine a target measurement interval based on a preset self-discharge rate threshold interval and a reference self-discharge rate dispersion; and to divide multiple batteries under test based on the target measurement interval and measurement time points to obtain multiple battery packs under test.

[0094] In one embodiment, the second voltage acquisition module 402 is further configured to calculate, based on the measurement time point, the voltage difference between the first voltage corresponding to the first measurement time point and the first voltage corresponding to a plurality of other measurement time points; classify the batteries under test whose voltage difference is less than a preset voltage difference threshold into a battery pack under test; and for the remaining unclassified batteries under test, return to the step of calculating, based on the measurement time point, the voltage difference between the first voltage corresponding to the first measurement time point and the first voltage corresponding to a plurality of other measurement time points, until a plurality of battery packs under test are obtained.

[0095] In one embodiment, the battery screening module 404 is further configured to sort the self-discharge rates of multiple current batteries under test in any battery pack under test to obtain a self-discharge rate sequence; determine a target self-discharge rate threshold range based on the self-discharge rate sequence; and screen the multiple current batteries under test based on the target self-discharge rate threshold range and the self-discharge rates of the multiple current batteries under test to obtain qualified batteries, thereby obtaining qualified batteries among the multiple batteries under test.

[0096] In one embodiment, the first voltage is obtained by subjecting multiple batteries under test to a first static condition in both a high-temperature environment and a normal-temperature environment until the voltage change of the multiple batteries under test in the normal-temperature environment is less than a preset threshold value, wherein the high-temperature environment is 40°C to 50°C; and / or, the second voltage is obtained by subjecting multiple batteries under test to a second static condition in the normal-temperature environment until the voltage change of the multiple batteries under test in the normal-temperature environment is less than or equal to the reference voltage change.

[0097] In one embodiment, the battery under test is a pouch cell, the preset pressurization container is a preset sealed container, and the pressurization source is gas; and / or, the preset pressurization parameters include a positive pressure value and a positive pressure duration, wherein the positive pressure value is 0.4 MPa to 0.8 MPa, the positive pressure duration is 4 h to 8 h, and the pressure value... Pressurization time ≥2MPa h.

[0098] Each module in the aforementioned battery sorting device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the memory of a computer device as software, so that the processor can call and execute the corresponding operations of each module.

[0099] Thirdly, this embodiment provides an electronic device, including a memory and a processor. The memory stores computer instructions, and when the computer instructions are executed by the processor, they implement the method of any of the above embodiments.

[0100] In one embodiment, this embodiment also provides an electronic device, which may be a server, and its internal structure diagram may be as follows. Figure 5As shown, this electronic device includes a processor, memory, input / output (I / O) interfaces, and a communication interface. The processor, memory, and I / O interfaces are connected via a system bus, and the communication interface is also connected to the system bus via the I / O interfaces. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer instructions, and a database. The internal memory provides the environment for the operation of the operating system and computer instructions stored in the non-volatile storage media. The database stores data involved in business data processing methods. The I / O interfaces are used for exchanging information between the processor and external devices. The communication interface is used for communicating with external terminals via a network connection. When the computer instructions are executed by the processor, a battery screening method is implemented.

[0101] Those skilled in the art will understand that Figure 5 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0102] Fourthly, embodiments of this application provide a computer-readable storage medium storing computer instructions thereon, which are loaded by a processor to execute the arrangements in any of the methods described above. In embodiments of this application, the storage medium may be a magnetic disk, an optical disk, a read-only memory (ROM), or a random access memory (RAM), etc.

[0103] Fifthly, embodiments of this application provide a computer program product, including a computer program or instructions, which are executed by a processor to implement the steps of any of the methods described above.

[0104] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0105] The battery screening method, electronic device, and computer-readable storage medium provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A battery screening method, characterized in that, Includes the following steps: Acquire the first voltage of multiple batteries under test after a first rest period starting from a preset charge level; After obtaining the second voltage of multiple batteries under test after being pressurized according to preset pressurization parameters and then subjected to a second settling period; Based on the first voltage, the second voltage, and the preset pressure parameters, the self-discharge rate of each battery under test is obtained; Based on the self-discharge rate, qualified batteries are determined among the multiple batteries to be tested.

2. The method according to claim 1, characterized in that, The step of obtaining the second voltage after the multiple batteries under test have been pressurized according to preset pressurization parameters and then subjected to a second settling period includes: Place multiple batteries under test into a pre-pressurized container; Using a pressure source, multiple batteries under test in the preset pressure container are pressurized according to preset pressure parameters; The second voltage of multiple batteries under test is measured after the pressurization process and the second settling period.

3. The method according to any one of claims 1-2, characterized in that, The method further includes: Obtain the measurement time points of the first voltage corresponding to each of the multiple batteries under test; Based on the measurement time points, multiple batteries under test are divided to obtain multiple battery packs under test; The step of obtaining the second voltage after the multiple batteries under test have been pressurized according to preset pressurization parameters and then subjected to a second settling period includes: After pressurizing multiple battery packs under test according to preset pressurization parameters, a second settling period is performed to obtain the second voltage of multiple batteries under test in each battery pack under test after the second settling period.

4. The method according to claim 3, characterized in that, The process of dividing the multiple batteries under test based on the measurement time points to obtain multiple battery packs under test includes: The target measurement range is determined based on the preset self-discharge rate threshold range and the reference self-discharge rate dispersion. Based on the target measurement interval and the measurement time point, the multiple batteries to be tested are divided to obtain multiple battery packs to be tested.

5. The method according to claim 3, characterized in that, The process of dividing the multiple batteries under test based on the measurement time points to obtain multiple battery packs under test includes: Based on the measurement time points, calculate the voltage difference between the first voltage corresponding to the first measurement time point and the first voltage corresponding to multiple other measurement time points; Batteries under test whose voltage difference is less than a preset voltage difference threshold are grouped into a single battery group. For the remaining undivided multiple batteries to be tested, return to the step of calculating the voltage difference between the first voltage corresponding to the first measurement time point and the first voltage corresponding to the multiple other measurement time points, based on the measurement time point, until multiple battery packs to be tested are obtained.

6. The method according to any one of claims 1-5, characterized in that, The step of determining the qualified batteries among the multiple batteries to be tested based on the self-discharge rate includes: For any number of batteries under test in a battery pack under test, the self-discharge rates of the batteries under test are sorted to obtain a self-discharge rate sequence. Based on the self-discharge rate sequence, the target self-discharge rate threshold range is determined; Based on the target self-discharge rate threshold range and the self-discharge rates of multiple current test batteries, multiple current test batteries are screened to obtain qualified batteries, thereby obtaining qualified batteries from multiple test batteries.

7. The method according to any one of claims 1-6, characterized in that, The first voltage is obtained by subjecting multiple test batteries to a first static condition under both high-temperature and normal-temperature environments until the voltage change of the multiple test batteries under the normal-temperature environment is less than a preset threshold value; wherein the high-temperature environment is 40°C to 50°C; and / or, The second voltage is obtained by subjecting multiple batteries under test to a second settling period at room temperature until the voltage change of the multiple batteries under test at room temperature is less than or equal to the reference voltage change.

8. The method according to any one of claims 1-7, characterized in that, The battery under test is a pouch cell, the preset pressurization container is a preset sealed container, and the pressurization source is gas; and / or, The preset pressurization parameters include pressure value and pressurization duration. The pressure value is 0.4 MPa to 0.8 MPa, and the pressurization duration is 4 h to 8 h.

9. An electronic device, characterized in that, The electronic device includes a processor and a memory, the memory storing a computer program configured to be executed by the processor to implement the steps of the method according to any one of claims 1 to 8.

10. A computer storage medium, characterized in that, The computer storage medium stores a computer program configured to be executed by a processor to implement the method of any one of claims 1 to 8.

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