A method for screening the self-discharge of a battery, an electronic device, and a storage medium.

Abstract

This application discloses a method, electronic device, and storage medium for screening the self-discharge of batteries. The method obtains a first screening range and a second screening range for screening the battery under test. The first screening range is determined based on a target mapping relationship between the battery's state of charge and its differential voltage, and is used for self-discharge rate screening. The second screening range is determined based on the battery's target battery association information and is used for self-discharge rate consistency screening. If the target self-discharge rate of the battery under test falls within both the first and second screening ranges, the battery is determined to be qualified; otherwise, it is determined to be unqualified. Thus, by changing the determination method of the first and second screening ranges, the screening accuracy of the first and second screening ranges is improved, avoiding multi-stage self-discharge screening of the battery, thereby reducing screening time while ensuring screening accuracy.

Description

Technical Field

[0001] This application relates to the field of battery screening technology, and in particular to a method for screening the self-discharge of batteries, an electronic device, and a storage medium. Background Technology

[0002] Existing battery self-discharge screening methods include two screening stages. The first screening stage involves subjecting the formed battery to constant-current discharge at a constant capacity. After 24 hours of rest, the initial open-circuit voltage (OCV1) is measured, followed by a 144-hour rest at room temperature, at which point the final open-circuit voltage (OCV2) is measured. Based on the initial and final open-circuit voltages (OCV1 and OCV2) and the formula K = (OCV1 - OCV2) / 144, the self-discharge rate (K) of the battery per unit time is determined. The first screening is then performed based on the self-discharge rate range, the σ screening range for self-discharge rate consistency, and the battery's self-discharge rate (K). The σ screening range for self-discharge rate can refer to a single-disk σ screening range, used for screening the same... The self-discharge rate of a batch of batteries (e.g., a tray) is calculated using the standard deviation (σ) to eliminate outliers, thus ensuring the consistency of the batch within a certain screening range. The second screening stage involves subjecting the batteries selected in the first stage to several days of high-temperature storage at 45°C and then at room temperature before shipment. A second screening is conducted based on the voltage range, the voltage difference σ range, and the voltage measured after the high-temperature and room-temperature storage. Batteries within the range are shipped normally; those outside the range are marked as defective and not allowed to be shipped.

[0003] However, the above-mentioned battery self-discharge screening method has the problem of being time-consuming. Summary of the Invention

[0004] The embodiments of this application provide a battery self-discharge screening method, electronic device, and storage medium, which aim to improve the screening accuracy of the first screening range and the second screening range by changing the way the first screening range and the second screening range are determined, so as to avoid multi-stage self-discharge screening of the battery, thereby reducing the screening time while ensuring the screening accuracy.

[0005] In a first aspect, embodiments of this application provide a self-discharge screening method, the method comprising: A first screening range and a second screening range are obtained for screening the batteries to be tested. The first screening range is used to screen the batteries for self-discharge rate and is determined based on the target mapping relationship between the battery's state of charge and the battery's differential voltage. The second screening range is used to screen the batteries for self-discharge rate consistency and is determined based on the battery's target battery association information. Determine the target self-discharge rate of the battery under test; If the target self-discharge rate is within the first screening range and the second screening range, the battery under test is determined to be qualified; otherwise, the battery under test is determined to be unqualified.

[0006] In one embodiment, the method for determining the first screening range includes: From multiple mapping relationships between the state of charge of the battery and the differential voltage of the battery, determine the target mapping relationship that matches the battery under test; In the target mapping relationship, each two adjacent states of charge other than the target state of charge are determined, as well as the differential voltage corresponding to each adjacent state of charge, wherein the target state of charge is used to indicate a state of charge value that is less than a preset state of charge value. Based on the differential voltage corresponding to each of the adjacent states of charge, the voltage drop ratio of each of the adjacent states of charge is determined, so as to determine the first voltage based on the target voltage drop ratio among the voltage drop ratios. The initial voltage is determined to be the final voltage of the first sample battery after it has been left to stand for a first time, which is the first voltage. The first screening range is determined based on the first voltage, the end voltage, and the first duration.

[0007] Thus, by constructing the dV / dQ-Q curve, the optimal OCV1 voltage plateau for measuring the K value can be determined, and based on this optimal OCV1 voltage plateau, a first screening range can be established. By increasing the ability of the first screening range to identify standard critical state cells with the K value, the accuracy of cell screening is improved.

[0008] In one embodiment, the construction step of each of the mapping relationships includes: Determine the target battery capacity of the second sample battery in a fully charged state, and based on the target battery capacity, determine the number of constant-capacity discharges required for the second sample battery to be discharged at constant capacity per unit battery capacity; Determine the second voltage of the second sample battery after it has been left to stand for a second time in a fully charged state; The second sample battery is subjected to constant-capacity discharge to reduce its capacity from the first battery capacity to the second battery capacity. The third voltage of the second sample battery after being left to stand for the second time is then determined. The first battery capacity is the battery capacity before this constant-capacity discharge, and the second battery capacity is the battery capacity to be achieved after this constant-capacity discharge. The differential voltage determined based on the second voltage and the third voltage is correlated with the state of charge determined based on the first battery capacity and the target battery capacity; The number of constant-capacity discharges is decremented so that, if the number of constant-capacity discharges is not zero, the second battery capacity is used as the new first battery capacity, the third voltage is used as the new second voltage, and the step of constant-capacity discharge of the second sample battery is returned to be executed; or, if the number of constant-capacity discharges is zero, a mapping relationship is determined based on the associated differential voltage and the state of charge.

[0009] In this way, a mapping relationship between the battery's state of charge and its differential voltage is established. This allows for the determination of the first screening range based on the target mapping relationship matched with the battery under test during the battery self-discharge screening process. This changes the way the first screening range is determined and improves the accuracy of screening batteries by self-discharge rate.

[0010] In some embodiments, the method for determining the correspondence between the preset fourth duration and the preset formation end voltage includes: The fourth sample battery after formation is subjected to a preset charge and discharge process until the voltage of the fourth sample battery reaches the preset formation end voltage. The preset formation end voltage is determined based on the preset fourth voltage, and the voltage difference between the preset formation end voltage and the preset fourth voltage is not greater than the preset voltage difference. Determine the sixth voltage of the fourth sample battery after it has been left to stand for a preset time, and update the cumulative standing time of the fourth sample battery. If the voltage difference between the sixth voltage and the preset fourth voltage is greater than the voltage difference threshold, return to the step of determining the sixth voltage of the fourth sample battery after it has been left to stand for a preset time, until the voltage difference between the sixth voltage and the preset fourth voltage is not greater than the voltage difference threshold. The cumulative resting time is used as the preset fourth duration, and a correspondence is established between the preset fourth duration and the preset formation end voltage.

[0011] Thus, by determining the correspondence between the preset fourth duration and the preset formation end voltage, the formation end voltage and the fourth duration can be determined under the condition that the optimal OCV1 of the measured K value is known, and the process of adjusting and determining the self-discharge rate of the battery under test based on the formation end voltage and the fourth duration can be carried out.

[0012] Secondly, embodiments of this application provide a self-discharge screening device, the self-discharge screening device comprising: The range acquisition module is used to acquire a first screening range and a second screening range for screening the battery under test. The first screening range is used to screen the battery for self-discharge rate. The first screening range is determined based on the target mapping relationship between the battery's state of charge and the battery's differential voltage. The second screening range is used to screen the battery for self-discharge rate consistency. The second screening range is determined based on the battery's target battery association information. A rate determination module is used to determine the target self-discharge rate of the battery under test; The screening module is used to determine that the battery under test is qualified if the target self-discharge rate is within the first screening range and the second screening range; otherwise, it determines that the battery under test is unqualified.

[0013] Thirdly, embodiments of this application provide an electronic device, the electronic device comprising: One or more processors; Memory; and One or more applications, wherein the one or more applications are stored in the memory and configured to be executed by the processor to implement the steps in the self-discharge screening method according to any one of the first aspects.

[0014] Fourthly, this application also provides a computer-readable storage medium having a computer program stored thereon, the computer program being loaded by a processor to perform the steps in the self-discharge screening method according to any one of the first aspects.

[0015] Fifthly, this application also provides a computer program product, including a computer program / instructions, which, when executed by a processor, are used to perform the steps in the self-discharge screening method described in any of the first aspects above.

[0016] The beneficial effects of the embodiments of this application are as follows: In the embodiments of this application, a first screening range and a second screening range are obtained to screen the battery under test. The first screening range is used to screen the battery based on its self-discharge rate, and is determined based on the target mapping relationship between the battery's state of charge and its differential voltage. The second screening range is used to screen the battery based on its self-discharge rate consistency, and is determined based on the battery's target battery association information. A target self-discharge rate for the battery under test is determined. If the target self-discharge rate is within both the first and second screening ranges, the battery under test is determined to be qualified; otherwise, it is determined to be unqualified. Thus, by changing the method of determining the first and second screening ranges, the screening accuracy of the first and second screening ranges is improved, avoiding multi-stage self-discharge screening of the battery, thereby reducing screening time while ensuring screening accuracy. Attached Figure Description

[0017] 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.

[0018] Figure 1 This is a schematic diagram illustrating an implementation scenario of the self-discharge screening method provided in the embodiments of this application; Figure 2 This is a schematic flowchart of the self-discharge screening method provided in the embodiments of this application; Figure 3 This is a partial schematic diagram of the dV / dQ-Q curve in the self-discharge screening method provided in the embodiments of this application; Figure 4 This is a schematic diagram of the existing K-value filtering range provided in the embodiments of this application; Figure 5 This is a schematic diagram of the voltage drop of good and defective batteries provided in the embodiments of this application; Figure 6 This is a schematic diagram of an embodiment of the capacity conversion device provided in this application; Figure 7 This is a schematic diagram of an embodiment of the electronic device provided in this application. Detailed Implementation

[0019] 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 a part of the embodiments of this application, and not all of the 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. At the same time, in the description of the embodiments of this application, the terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0020] This application proposes a self-discharge screening method, apparatus, electronic device, storage medium, and computer program product. The self-discharge screening apparatus can be integrated into an electronic device, which can be a server such as a self-discharge screening system, or a terminal controlled by a self-discharge screening system, etc.

[0021] The server can be a standalone physical server, a server cluster or distributed system composed of multiple physical servers, or a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communication, middleware services, domain name services, security services, network acceleration services (Content Delivery Network, CDN), as well as big data and artificial intelligence platforms.

[0022] The terminal can be a smartphone, tablet, laptop, desktop computer, smart speaker, smartwatch, etc., but is not limited to these. The terminal and the server can be connected directly or indirectly through wired or wireless communication, which is not limited herein.

[0023] Please see Figure 1 Taking the integration of a self-discharge screening device into electronic devices as an example, Figure 1This is a schematic diagram illustrating an implementation scenario of the self-discharge screening method provided in this application. The electronic device can be a terminal device, which acquires a first screening range and a second screening range for screening the battery under test. The first screening range is used to screen the battery's self-discharge rate and is determined based on the target mapping relationship between the battery's state of charge and its differential voltage. The second screening range is used to screen the battery's self-discharge rate consistency and is determined based on the battery's target battery association information. The target self-discharge rate of the battery under test is determined. If the target self-discharge rate is within both the first and second screening ranges, the battery under test is determined to be qualified; otherwise, it is determined to be unqualified. Thus, by changing the method of determining the first and second screening ranges, the screening accuracy of the first and second screening ranges is improved, avoiding multi-stage self-discharge screening of the battery, thereby reducing screening time while ensuring screening accuracy.

[0024] It should be noted that, Figure 1 The schematic diagram illustrating the implementation environment of the self-discharge screening method is merely an example. The implementation environment of the self-discharge screening method described in this application is intended to more clearly illustrate the technical solutions of this application and does not constitute a limitation on the technical solutions provided in this application. Those skilled in the art will understand that, with the evolution of self-discharge screening and the emergence of new business scenarios, the technical solutions provided in this application are also applicable to similar technical problems.

[0025] The solutions provided in this application are specifically illustrated through the following embodiments. It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of the embodiments.

[0026] This embodiment will be described from the perspective of a self-discharge screening device, which can be integrated into an electronic device, such as a terminal device and / or a server, and this application does not impose any limitations on it.

[0027] Please see Figure 2 , Figure 2 This is a flowchart illustrating a self-discharge screening method provided in an embodiment of this application. The self-discharge screening method is applied to electronic devices and may include the following steps S101 to S103: S101. Obtain a first screening range and a second screening range for screening the battery to be tested. The first screening range is used to screen the battery for self-discharge rate. The first screening range is determined based on the target mapping relationship between the battery's state of charge and the battery's differential voltage. The second screening range is used to screen the battery for self-discharge rate consistency. The second screening range is determined based on the battery's target battery association information.

[0028] Here, "battery under test" refers to the batteries in the batch to be tested. The batch contains multiple batteries, such as more than one hundred. All batteries within the batch share the same battery system, were produced around the same time, used the same materials, and have the same capacity.

[0029] The self-discharge rate refers to the voltage drop of a battery over a certain period of time.

[0030] Specifically, K = (OCV1 - OCV2) / t.

[0031] Where K is the self-discharge rate, (OCV1-OCV2) refers to the voltage drop generated during the period when the battery's open-circuit voltage changes from the first open-circuit voltage OCV1 to the second open-circuit voltage OCV2, and t is the resting time (i.e. a certain amount of time) required for the battery's open-circuit voltage to change from the first open-circuit voltage OCV1 to the second open-circuit voltage OCV2.

[0032] Among them, self-discharge rate consistency refers to the uniformity and similarity of self-discharge characteristics of a group of batteries (such as batteries from the same batch or of the same model).

[0033] The first screening range indicates the screening range for self-discharge rate screening of batteries in the test batch. The second screening range indicates the screening range for self-discharge rate consistency screening of batteries in the test batch.

[0034] In this way, by screening the self-discharge rate and self-discharge rate consistency of the batteries under test, it is possible to determine whether the batteries under test are qualified, and at the same time, remove batteries with poor consistency in the batch under test, so as to improve the overall quality of the batch of batteries under test.

[0035] Specifically, the first screening range is determined based on the target mapping relationship that matches the battery under test (such as model matching, battery type matching, battery batch matching) among multiple mapping relationships between the battery's state of charge and the battery's differential voltage.

[0036] Therefore, each mapping relationship corresponds to a battery identifier. A battery identifier is an identifier used to distinguish different types of batteries. Battery identifiers may include, but are not limited to, battery type, battery model, and batch number; their specific details can be adjusted according to actual circumstances and are not limited here. This application preferably uses the battery model as the battery identifier, with different battery models corresponding to different mapping relationships.

[0037] The mapping relationship between the battery's state of charge and its differential voltage is determined before battery self-discharge screening.

[0038] Here, differential voltage refers to the voltage change (dV) corresponding to a unit capacity change (dQ).

[0039] There are multiple ways to construct mapping relationships, and the specific methods can be adjusted according to the actual situation. No restrictions are imposed here.

[0040] Specifically, the construction of each mapping relationship may include the following steps: Determine the target battery capacity of the second sample battery under full charge, and based on the target battery capacity, determine the number of constant-capacity discharges required for the second sample battery to be discharged at constant capacity per unit battery capacity. Determine the second voltage of the second sample battery after it has been left to stand for a second period of time in a fully charged state; The second sample battery is subjected to constant-capacity discharge to reduce its capacity from the first battery capacity to the second battery capacity. The third voltage of the second sample battery after being left to stand for a second time is then determined. The first battery capacity is the battery capacity before this constant-capacity discharge, and the second battery capacity is the battery capacity that needs to be achieved after this constant-capacity discharge. The differential voltage determined based on the second and third voltages is correlated with the state of charge determined based on the first battery capacity and the target battery capacity; The number of constant-capacity discharges is decremented. If the number of constant-capacity discharges is not zero, the second battery capacity is used as the new first battery capacity, the third voltage is used as the new second voltage, and the process of performing constant-capacity discharge on the second sample battery is returned. Alternatively, if the number of constant-capacity discharges is zero, the mapping relationship is determined based on the associated differential voltage and state of charge.

[0041] The second sample battery refers to one or more sample batteries used to construct a mapping relationship. These sample batteries share the same battery identifier (such as battery model, battery type, or batch number). In other words, a mapping relationship is constructed using this second sample battery and its associated battery identifier. The target battery capacity refers to the actual battery capacity of the second sample battery in a fully charged state. It is understandable that the target battery capacity differs for batteries with different identifiers.

[0042] Specifically, a first constant current method can be used to determine the target battery capacity of the second sample battery under full charge. Here, the first constant current method refers to the constant current method used to measure the target battery capacity of the second sample battery. A constant current method means a control method that keeps the current constant. For example, the first constant current method is a 0.2C constant current method, which means discharging at a current of 0.2 times the total battery capacity.

[0043] The steps for determining the target battery capacity of the second sample battery in a fully charged state using the first constant current method include: charging the second sample battery until it reaches a fully charged state, and then using the first constant current method to detect the capacity of the second sample battery in the fully charged state, so as to use the detected battery capacity as the target battery capacity of the second sample battery.

[0044] The constant-capacity discharge cycle refers to the number of times a constant-capacity discharge process is performed on the second sample battery according to its unit battery capacity to cover all states of charge contained in a mapping relationship of the second sample battery.

[0045] Specifically, the number of constant-capacity discharge cycles is determined based on the target battery capacity and the unit battery capacity. For example, when the target battery capacity is 1000mAh and the unit battery capacity is 5mAh, the number of constant-capacity discharge cycles is 201, i.e., 1000mAh / 5mAh+1=201 cycles. This covers all changes in battery capacity based on the unit battery capacity (such as 1000mAh, 995mAh, 990mAh, ..., 5mAh, 0mAh, etc.), thereby determining the correlation between the differential voltage and state of charge of the battery that matches the battery identifier of the second sample battery.

[0046] The second duration refers to the resting time required to measure the voltage of the second sample battery.

[0047] The second voltage refers to the voltage measured after a certain period of self-discharge of the second sample battery in a fully charged state.

[0048] Specifically, the step of determining the second voltage of the second sample battery in a fully charged state after being left to stand for a second time includes: allowing the second sample battery in a fully charged state to stand until the second time is reached, and then measuring the second sample battery to determine the second voltage of the second sample battery after self-discharge for the second time.

[0049] Among them, a second constant current method can be used to discharge the second sample battery at a constant capacity, so as to reduce the capacity of the first battery to the capacity of the second battery.

[0050] Specifically, a second constant current method is used to discharge the second sample battery at a constant capacity according to the unit battery capacity, so as to reduce the battery capacity of the second sample battery from the first battery capacity to the second battery capacity, and after the second sample battery is left to stand for a second time, the third voltage of the second sample battery is determined.

[0051] The second constant current method refers to a constant current method that discharges the second sample battery at a constant capacity according to the unit battery capacity. For example, the second constant current method is the 0.01C constant current method. The 0.01C constant current method means discharging at a current of 0.01 times the total battery capacity, that is, the battery charge and discharge rate is one percent of its battery capacity (i.e., the target battery capacity).

[0052] Wherein, the first battery capacity is the battery capacity before this fixed-capacity discharge (i.e., initially, the first battery capacity is the target battery capacity), and the second battery capacity is the battery capacity to be achieved after this fixed-capacity discharge.

[0053] The third voltage refers to the voltage measured after a certain period of self-discharge of the second sample battery, after the battery capacity of the second sample battery has decreased from the first battery capacity to the second battery capacity.

[0054] Specifically, the steps of using a second constant current method to perform constant-capacity discharge on the second sample battery according to the unit battery capacity to reduce the battery capacity of the second sample battery from the first battery capacity to the second battery capacity, and then letting the second sample battery stand for a second time to determine the third voltage of the second sample battery include: using a second constant current method to perform constant-capacity discharge on the second sample battery according to the unit battery capacity to reduce the battery capacity of the second sample battery from the first battery capacity to the second battery capacity, and then letting the second sample battery stand for a second time until the second time is reached, and then measuring the second sample battery to determine the third voltage of the second sample battery after the second time of self-discharge.

[0055] The differential voltage refers to the ratio between the difference between the second and third voltages (i.e., dV) and the unit battery capacity (i.e., dQ).

[0056] Here, the state of charge refers to the ratio between the capacity of the first battery and the capacity of the target battery (i.e., Q).

[0057] The above mapping relationship includes multiple correlations between differential voltage and state of charge, which cover multiple changes in unit cell capacity of the second sample cell from the target cell capacity to 0.

[0058] For example, to facilitate understanding of the construction steps of each of the above mapping relationships, the following specific embodiments are explained. For any preset battery identifier, a battery under the preset battery identifier (such as the 50EV2 battery model) (i.e., the second sample battery) is randomly selected, and the dV / dQ-Q curve (i.e., the mapping relationship between the battery's state of charge and the battery's differential voltage) is constructed according to the following general steps: Step 10: Fully charge the battery to 4.2V; The battery can be a ternary lithium battery, and 4.2V is the full charge voltage of the ternary lithium battery, which means that the battery is fully charged to 4.2V so that the battery is in a fully charged state.

[0059] Step 20: 0.2C discharge capacity calibration to determine the battery capacity CAP; The first constant current method is 0.2C, and the target battery capacity is the battery capacity CAP.

[0060] Step 30: Recharge the battery to 4.2V, let it sit for 1 hour, and read the voltage in the last second as the battery voltage. During battery calibration, self-discharge causes voltage loss, necessitating a full recharge to 4.2V. The second calibration time is 1 hour. The voltage read in step 30 is the second voltage of the second sample battery.

[0061] Step 40: Discharge at 0.01C to 0.5% CAP, let stand for 1 hour after discharge, and read the voltage in the last second as the battery voltage; The second constant current method is 0.01C, the unit battery capacity is 0.5%CAP, and the voltage read in step 40 is the third voltage of the second sample battery.

[0062] Step 50: Repeat step 40 201 times to construct the dV / dQ-Q curve based on the voltage and capacity information from each repetition in step 40.

[0063] The dV / dQ-Q curve is used to describe the mapping relationship between the state of charge of the battery and the differential voltage of the battery under the preset battery label.

[0064] For example, such as Figure 3 As shown, Figure 3 This is a partial schematic diagram of the dV / dQ-Q curve provided in an embodiment of this application. Please refer to... Figure 3 Battery model 21 is the 50EV2 model. Battery model 21 is the preset battery identifier matched by the mapping relationship of the dV / dQ-Q curve. The vertical axis 22 is the differential voltage of the battery, i.e., dV / dQ, where dV is used to indicate the voltage difference between two adjacent data points, and dQ is used to indicate the capacity increment (i.e., unit battery capacity) corresponding to dV. The horizontal axis 23 is the state of charge of the battery.

[0065] In this way, a mapping relationship between the state of charge of a battery and its differential voltage is established. This allows for the determination of the first screening range based on the target mapping relationship that matches the battery identifier of the battery under test during the battery self-discharge screening process. This changes the way the first screening range is determined and improves the accuracy of self-discharge rate screening of batteries.

[0066] In some embodiments, the determination of the first screening range includes: determining a target mapping relationship matching the battery under test from multiple mapping relationships between the state of charge (SBC) of the battery and the differential voltage of the battery; determining each pair of adjacent SBCs other than the target SBC, and the differential voltage corresponding to each adjacent SBC, wherein the target SBC is used to indicate the SBC value is less than a preset SBC value; determining the voltage drop ratio of each adjacent SBC based on the differential voltage corresponding to each adjacent SBC, so as to determine a first voltage based on the target voltage drop ratio among the voltage drop ratios; determining the end voltage of the first sample battery after it has been left to stand for a first time with the initial voltage being the first voltage; and determining the first screening range based on the first voltage, the end voltage, and the first time.

[0067] The preset state of charge (SOC) value is used to distinguish whether an internal reaction can occur within the battery. It should be noted that when the SOC value is very low, the internal reaction cannot occur. The preset SOC value can be adjusted according to actual conditions; there are no restrictions here. For example, a preset SOC value of 25% SOC. Another example is a preset SOC value of 30% SOC.

[0068] The target pressure drop ratio refers to the maximum pressure drop ratio among all pressure drop ratios.

[0069] Here, the first voltage refers to the initial voltage corresponding to the voltage drop of the larger state of charge among the adjacent states of charge corresponding to the target voltage drop ratio. The first sample battery refers to the battery used to determine the K value in the first screening range. The first duration refers to the resting time required to measure the final voltage of the first sample battery.

[0070] Specifically, the process of determining the first screening range based on the first voltage, the end voltage, and the first duration can be understood as follows: based on the ratio between the voltage drop between the first voltage and the end voltage and the first duration, determine the optimal K value for self-discharge rate screening, and form the first screening range based on the optimal K value.

[0071] For example Figure 3 The dV / dQ-Q curve shown serves as a target mapping relationship, explaining the determination of the first screening range. Having already obtained... Figure 3Given the dV / dQ-Q curve shown, it is necessary to select the OCV1 voltage platform from the dV / dQ-Q curve to measure the optimal K value. In this application, the OCV1 voltage platform for measuring the optimal K value is as follows: Figure 3 In the dV / dQ-Q curve shown, dV needs to be determined. SOC低 / dV SOC高 The maximum value (i.e., the target voltage drop ratio) is determined. Then, based on the test data, the larger of the two adjacent states of charge at which the maximum value is obtained is determined, along with the initial voltage corresponding to the larger state of charge. The initial voltage corresponding to the larger state of charge is used as the OCV1 voltage platform for measuring the optimal K value.

[0072] It should be noted that the existing K-value screening range is a fixed K-value. The difficulty in K-value screening lies in the identification of standard critical state cells. Standard critical state cells refer to cells with K-values ​​near the standard. It is impossible to accurately determine whether a standard critical state cell is a good or defective cell. Figure 4 As shown, Figure 4 The x-axis represents the number of batteries, and the y-axis represents the K-value, with a K-value selection range of (0.02, 0.08). Transforming the batteries in the first image reveals that most batteries have K-values ​​concentrated in (0.05, 0.06), while a small portion have K-values ​​concentrated in (0.065, 0.08). Batteries concentrated in (0.065, 0.08) are K-value standard critical state batteries. Setting the K-value selection range to (0.02, 0.08) for compatibility with K-value standard critical state batteries can easily lead to missed defective batteries. Conversely, setting the K-value selection range to (0.02, 0.06) for incompatibility with K-value standard critical state batteries can easily lead to good batteries being mistakenly identified as defective. Therefore, existing technology requires a second stage of battery self-discharge screening.

[0073] The inventors discovered that the difficulty in K-value selection lies in identifying the standard critical state cell. This application addresses this by constructing a dV / dQ-Q curve, considering only the relationship between two adjacent states of charge within the curve. After subtracting the overlapping region from adjacent states of charge, a larger voltage drop ratio indicates better performance in identifying the standard critical state cell. Figure 5 As shown, by keeping the initial SOC state control of good and defective batteries consistent, the voltage drop range of good batteries within a certain time period can be [missing information]. Figure 5 The voltage drop area 25 in the middle, the voltage drop area of ​​defective batteries within a certain period of time can be Figure 5 In the voltage drop region 24, there is an overlap between the voltage drop region 25 of the good battery and the voltage drop region 24 of the defective battery. Subtracting the voltage drop region 25 of the good battery from the voltage drop region 24 of the defective battery yields a non-overlapping region.

[0074] It should be noted that the dV / dQ-Q curve is used to represent the rate of change of voltage of a battery under a certain state of charge. The physical meaning of integrating the dV / dQ-Q curve with respect to the battery's state of charge is the voltage drop of the battery from the initial state of charge to the final state of charge.

[0075] Since the discharge capacity is the same each time the dV / dQ-Q curve is plotted, ΔV SOC低 / ΔV SOC高 ≡dV SOC低 / dV SOC高 Wherein, ΔV SOC低 It refers to the voltage drop ΔV at the end of the state of charge during self-discharge. SOC高 This refers to the voltage drop during the initial state of charge in the self-discharge process. dV SOC低 V refers to the voltage drop at the end of the state of charge during self-discharge. SOC高 This refers to the voltage drop during the initial state of charge in the self-discharge process. dV is calculated from the dV / dQ-Q curve. SOC低 / dV SOC高 The maximum value is then determined based on the test data, and the SOC state at which the maximum value is achieved and its corresponding voltage are determined. This voltage is the optimal voltage plateau for measuring the K value.

[0076] Thus, by constructing the dV / dQ-Q curve, the optimal OCV1 voltage plateau for measuring the K value can be determined, and based on this optimal OCV1 voltage plateau, a first screening range can be established. By increasing the ability of the first screening range to identify standard critical state cells with the K value, the accuracy of cell screening is improved.

[0077] It should be noted that there are multiple ways to determine the second screening range, and the specific method can be adjusted according to the actual situation.

[0078] In some embodiments, the determination of the second screening range includes: determining target battery association information that matches the battery under test from multiple battery association information; determining a first screening index value and a first self-discharge rate deviation value based on the first self-discharge rate information of the target battery that matches the battery under test; and determining the second screening range based on the first self-discharge rate deviation value and the product between the screening coefficient corresponding to the target battery association information and the first screening index value.

[0079] Among them, battery-related information refers to information associated with the battery, including but not limited to differential pressure, percentage of qualified batteries, and percentage of batteries that meet preset quality standards. The specific information can be adjusted according to actual conditions, and there are no restrictions here.

[0080] The screening coefficient refers to the coefficient of the first screening index value used for screening the consistency of self-discharge rate.

[0081] The target battery refers to a good battery that matches the battery label of the battery under test. A good battery is also a qualified battery.

[0082] The first screening index value can refer to the standard deviation determined based on the self-discharge rate contained in the first self-discharge rate information, or other index values. The first self-discharge rate deviation value can refer to the median deviation determined based on the self-discharge rate contained in the first self-discharge rate information, or other deviation values. The specific first screening index value and the first self-discharge rate deviation value can be adjusted according to the actual situation, and are not limited here.

[0083] The method for determining the battery association information includes: the second self-discharge rate information of the third sample battery after it has been left to stand for a third time; determining the preset second screening range based on the deviation value of the second self-discharge rate and the product between the preset screening coefficient and the second screening index value corresponding to the third sample battery; screening the third sample battery through the preset second screening range to obtain the screening result, and determining the battery association information of the third sample battery under the preset screening coefficient based on the screening result.

[0084] The third sample battery refers to the sample battery used to determine the second screening range.

[0085] The battery association information is used to indicate the association information of the third sample battery with each preset screening coefficient. There can be various types of battery association information, and its specific details can be adjusted according to actual circumstances; this application does not impose any restrictions. For example, the battery association information may include at least one of the following: the voltage difference of qualified sample batteries in the third sample battery group; the first percentage of batteries in the third sample battery group that were mistakenly judged as qualified sample batteries; the second percentage of batteries in the third sample battery group that meet the preset quality standard; and the target probability that all batteries in the same batch of the third sample battery group meet the preset quality standard.

[0086] The third duration is used to indicate the resting time required to measure the second self-discharge rate information of the third sample battery.

[0087] The second screening index value can refer to the standard deviation determined based on the self-discharge rate included in the second self-discharge rate information, or other index values. The second self-discharge rate deviation value can refer to the median deviation determined based on the self-discharge rate included in the second self-discharge rate information, or other deviation values. The specific second screening index value and the second self-discharge rate deviation value can be adjusted according to the actual situation, and there are no restrictions here.

[0088] There is a corresponding relationship between the preset second filtering range and the preset filtering coefficient.

[0089] The steps described above for determining the screening coefficients for self-discharge rate consistency screening based on the third sample battery and the battery association information of the third sample battery under each preset screening coefficient include: determining the target battery association information from each battery association information, and using the preset screening coefficient corresponding to the determined target battery association information as the screening coefficient.

[0090] The target battery association information can be determined based on the battery association information, and its specific details can be adjusted according to actual circumstances; no restrictions are imposed here. For example, if the battery association information includes differential pressure, the target battery association information is the battery association information with the smallest differential pressure. If the battery association information includes a first percentage, the target battery association information is the battery association information with the smallest first percentage. If the battery association information includes both differential pressure and the first percentage, the target battery association information is the battery association information with both differential pressure and the smallest first percentage. If the battery association information includes a second percentage, the target battery association information is the battery association information with the largest second percentage. If the battery association information includes a target probability, the target battery association information is the battery association information with the largest target probability. If the battery association information includes both the second percentage and the target probability, the target battery association information is the battery association information with both the second percentage and the largest target probability. If the battery association information includes differential pressure, the first percentage, the second percentage, and the target probability, the target battery association information is the battery association information with the smallest differential pressure and the smallest first percentage, and the largest second percentage and the largest target probability.

[0091] For example, a battery is selected for experimentation, stored at room temperature for 180 days, and its voltage is tested periodically. Under the premise of ensuring that the voltage difference and the first proportion are minimized, the battery association information with the second proportion and the target probability is selected as the target battery association information. The preset screening coefficient corresponding to the target battery association information is used as the screening coefficient.

[0092] In this way, by analyzing battery-related information, the method of determining the second screening range can be changed, thereby improving product yield and reducing production energy consumption.

[0093] S102. Determine the target self-discharge rate of the battery under test.

[0094] The target self-discharge rate refers to the self-discharge rate of the battery under test.

[0095] Specifically, the process of determining the target self-discharge rate of the battery under test includes: performing a preset charge-discharge treatment on the battery under test after formation until the voltage of the battery under test reaches the formation end voltage; determining the fourth voltage of the battery under test after a fourth resting time, and the fifth voltage of the battery under test after a fifth resting time, wherein the fourth resting time is determined based on the correspondence between the preset fourth resting time and the preset formation end voltage, and the formation end voltage; and determining the target self-discharge rate of the battery under test based on the fourth voltage, the fifth voltage, and the fifth resting time.

[0096] The preset charge / discharge processes include, but are not limited to, constant current discharge, constant current and constant voltage charging, and constant current and constant voltage charge / discharge processes, which can be adjusted according to actual conditions. The purpose of the preset charge / discharge processes is to improve OCV1 consistency.

[0097] The formation termination voltage is determined based on the optimal OCV1 of the measured K value within the first screening range.

[0098] The fourth duration refers to the resting time required to measure the fourth voltage, which is the initial voltage during the self-discharge rate calculation of the battery under test. It can be understood that the fourth voltage is theoretically the optimal OCV1 for measuring the K value, but in practice it is a voltage value close to the optimal OCV1 for measuring the K value.

[0099] The fifth duration refers to the resting time required to measure the fifth voltage, and the fifth voltage refers to the ending voltage during the self-discharge rate calculation process of the battery under test.

[0100] The method for determining the correspondence between the preset fourth duration and the preset formation end voltage includes: performing a preset charge-discharge process on the fourth sample battery after formation until the voltage of the fourth sample battery reaches the preset formation end voltage, wherein the preset formation end voltage is determined based on the preset fourth voltage, and the voltage difference between the preset formation end voltage and the preset fourth voltage is not greater than the preset voltage difference; determining the sixth voltage of the fourth sample battery after resting for the preset duration, and updating the cumulative resting duration of the fourth sample battery; if the voltage difference between the sixth voltage and the preset fourth voltage is greater than the voltage difference threshold, returning to the step of determining the sixth voltage of the fourth sample battery after resting for the preset duration, until the voltage difference between the sixth voltage and the preset fourth voltage is not greater than the voltage difference threshold; using the cumulative resting duration as the preset fourth duration, and establishing the correspondence between the preset fourth duration and the preset formation end voltage.

[0101] The fourth sample cell refers to the sample cell used to determine the correspondence between the preset fourth duration and the preset formation end voltage.

[0102] It should be noted that the preset formation end voltage is slightly higher than the preset fourth voltage. The preset voltage difference can be set according to actual conditions and is not limited here. For example, the preset voltage difference is 8.

[0103] The preset duration refers to the resting time required to measure the sixth voltage. The sixth voltage is the intermediate voltage used in the self-discharge rate calculation of the battery under test.

[0104] The voltage difference threshold refers to the voltage difference threshold used to identify whether the sixth voltage can be considered as the preset fourth voltage. It can be set according to actual conditions and is not restricted here. For example, the preset voltage difference value is 0.5.

[0105] The cumulative settling time refers to the cumulative time from the preset formation end voltage until the voltage difference between the sixth voltage and the preset fourth voltage is no greater than the voltage difference threshold.

[0106] For example, the fourth sample battery after formation is subjected to a preset charge and discharge process until the voltage of the fourth sample battery reaches the formation end voltage. The voltage of the battery is tested every hour (i.e., preset duration) during the room temperature resting process, and the standard RT3 duration (i.e., the fourth duration) of each model is output.

[0107] Thus, by determining the correspondence between the preset fourth duration and the preset formation end voltage, the formation end voltage and the fourth duration can be determined when the optimal OCV1 (the theoretical fourth voltage) of the measured K value is known, and the process of adjusting and determining the self-discharge rate of the battery under test based on the formation end voltage and the fourth duration can be carried out.

[0108] Specifically, the self-discharge screening process of this application is as follows: After formation, the battery is subjected to a preset charge-discharge treatment to reach the formation end voltage. After standing for four hours, the initial OCV1 is tested. Then, after standing at room temperature for 144 hours (or other parameters), the battery's final open-circuit voltage OCV2 is tested. Based on the battery's initial open-circuit voltage OCV1 and final open-circuit voltage OCV2, and the formula K=(OCV1-OCV2) / 144, the target self-discharge rate of the battery under test per unit time is determined. The battery under test is then screened according to the first screening range and the second screening range.

[0109] S103. If the target self-discharge rate is within the first screening range and the second screening range, the battery under test is determined to be qualified; otherwise, the battery under test is determined to be unqualified.

[0110] Thus, using the self-discharge screening method described above, a first screening range and a second screening range are obtained for screening the battery under test. The first screening range is used to screen the battery based on its self-discharge rate, and is determined based on the target mapping relationship between the battery's state of charge and its differential voltage. The second screening range is used to screen the battery based on its self-discharge rate consistency, and is determined based on the battery's target battery association information. The target self-discharge rate of the battery under test is determined. If the target self-discharge rate falls within both the first and second screening ranges, the battery under test is deemed qualified; otherwise, it is deemed unqualified. By changing the method of determining the first and second screening ranges, the screening accuracy of the first and second screening ranges is improved, avoiding multi-stage self-discharge screening of the battery, thereby reducing screening time while maintaining screening accuracy.

[0111] To better implement the above methods, embodiments of this application also provide a self-discharge screening device, which can be integrated into an electronic device, such as a terminal or a server. Figure 6 As shown in the figure, this application embodiment also provides a self-discharge screening device, which includes: The range acquisition module 301 is used to acquire a first screening range and a second screening range for screening the battery under test. The first screening range is used to screen the battery for self-discharge rate. The first screening range is determined based on the target mapping relationship between the battery's state of charge and the battery's differential voltage. The second screening range is used to screen the battery for self-discharge rate consistency. The second screening range is determined based on the battery's target battery association information. The rate determination module 302 is used to determine the target self-discharge rate of the battery under test. The screening module 303 is used to determine that the battery under test is qualified if the target self-discharge rate is within the first screening range and within the second screening range; otherwise, it determines that the battery under test is unqualified.

[0112] In one embodiment, the method for determining the first screening range includes: The mapping relationship determination unit is used to determine the target mapping relationship that matches the battery under test from multiple mapping relationships between the state of charge of the battery and the differential voltage of the battery. The first information determining unit is used to determine every two adjacent states of charge other than the target state of charge in the target mapping relationship, and the differential voltage corresponding to each adjacent state of charge, wherein the target state of charge is used to indicate the state of charge value is less than the preset state of charge value. The first voltage determination unit is used to determine the voltage drop ratio of each adjacent state of charge based on the differential voltage corresponding to each adjacent state of charge, so as to determine the first voltage based on the target voltage drop ratio among the voltage drop ratios. The termination voltage determination unit is used to determine the termination voltage of a first sample battery with an initial voltage of the first voltage after it has been left to stand for a first time. The first range determination unit is used to determine the first screening range based on the first voltage, the end voltage, and the first duration.

[0113] In one embodiment, the construction step of each of the above mapping relationships includes: The capacity determination unit is used to determine the target battery capacity of the second sample battery in a fully charged state, so as to determine the number of constant-capacity discharges required for the second sample battery to be discharged at constant capacity according to the unit battery capacity based on the target battery capacity. The second voltage determination unit is used to determine the second voltage of the second sample battery after it has been left to stand for a second time in a fully charged state. The discharge unit is used to perform constant-capacity discharge on the second sample battery so as to determine the third voltage of the second sample battery after it has been left to stand for a second time after the capacity of the first battery has been reduced from the capacity of the first battery to the capacity of the second battery. The first battery capacity is the battery capacity before this constant-capacity discharge, and the second battery capacity is the battery capacity to be reached after this constant-capacity discharge. The correlation unit is used to correlate the differential voltage determined based on the second voltage and the third voltage, and the state of charge determined based on the first battery capacity and the target battery capacity. The first loop unit is used to decrement the number of constant-capacity discharges. If the number of constant-capacity discharges is not zero, the second battery capacity is used as the new first battery capacity, the third voltage is used as the new second voltage, and the step of constant-capacity discharge on the second sample battery is returned. Alternatively, if the number of constant-capacity discharges is zero, the mapping relationship is determined based on the associated differential voltage and state of charge.

[0114] In one embodiment, the target battery capacity is determined based on a first constant current method, which includes a 0.2C constant current method; The above constant-capacity discharge is achieved based on a second constant current method, which includes a 0.01C constant current method.

[0115] In one embodiment, the method for determining the second screening range includes: The second information determining unit is used to determine the target battery association information that matches the battery under test from multiple battery association information. The third information determining unit is used to determine the first screening index value and the first self-discharge rate deviation value based on the first self-discharge rate information of the target battery that matches the battery under test. The second range determination unit is used to determine the second screening range based on the first self-discharge rate deviation value and the product between the screening coefficient corresponding to the target battery association information and the first screening index value.

[0116] In one embodiment, the method for determining each of the above-mentioned battery association information includes: The fourth information determination unit is used to determine the second self-discharge rate information of the third sample battery after it has been left to stand for a third time. The fifth information determining unit is used to determine the second screening index value and the second self-discharge rate deviation value based on the second self-discharge rate information. The third range determination unit is used to determine the preset second screening range based on the second self-discharge rate deviation value and the product between the preset screening coefficient corresponding to the third sample battery and the second screening index value. The sixth information determination unit is used to filter the third sample battery through a preset second filtering range, obtain the filtering results, and determine the battery association information of the third sample battery under the preset filtering coefficient based on the filtering results.

[0117] In some embodiments, the battery association information mentioned above includes at least one of the following: the voltage difference of qualified sample batteries in the third sample batteries, the first proportion of batteries in the third sample batteries that were mistakenly judged as qualified sample batteries, the second proportion of batteries in the third sample batteries that meet the preset quality standard, and the target probability that all batteries in the same batch of the third sample batteries meet the preset quality standard. When the battery association information includes differential pressure and first proportion, the target battery association information is the battery association information with the smallest differential pressure and first proportion. When the battery association information includes the second proportion and the target probability, the target battery association information is the battery association information with the highest second proportion and the highest target probability.

[0118] In some embodiments, the rate determination module 302 determines the target self-discharge rate of the battery under test, including: The first pre-processing unit is used to perform preset charge and discharge treatment on the battery under test after formation until the voltage of the battery under test reaches the formation end voltage. The voltage first determining unit is used to determine the fourth voltage of the battery under test after it has been left to stand for a fourth time, and the fifth voltage of the battery under test after it has been left to stand for a fifth time. The fourth time is determined based on the formation end voltage and the correspondence between the preset fourth time and the preset formation end voltage. The rate determination unit is used to determine the target self-discharge rate of the battery under test based on the fourth voltage, the fifth voltage, and the fifth duration.

[0119] In some embodiments, the method for determining the correspondence between the preset fourth duration and the preset formation end voltage includes: The second preprocessing unit is used to perform a preset charge-discharge process on the fourth sample battery after formation until the voltage of the fourth sample battery reaches the preset formation end voltage. The preset formation end voltage is determined based on the preset fourth voltage, and the voltage difference between the preset formation end voltage and the preset fourth voltage is not greater than the preset voltage difference. The second voltage determination unit is used to determine the sixth voltage of the fourth sample battery after it has been left to stand for a preset time, and to update the cumulative standing time of the fourth sample battery. The second loop unit is used to return to the step of determining the sixth voltage of the fourth sample battery after it has been left to stand for a preset time if the voltage difference between the sixth voltage and the preset fourth voltage is greater than the voltage difference threshold, until the voltage difference between the sixth voltage and the preset fourth voltage is not greater than the voltage difference threshold. The second relationship determination unit is used to take the cumulative resting time as the preset fourth time and establish the correspondence between the preset fourth time and the preset formation end voltage.

[0120] Thus, using the aforementioned self-discharge screening device, the range acquisition module 301 acquires a first screening range and a second screening range for screening the battery under test. The first screening range is used to screen the battery based on its self-discharge rate, and is determined based on the target mapping relationship between the battery's state of charge and its differential voltage. The second screening range is used to screen the battery based on its self-discharge rate consistency, and is determined based on the battery's target battery association information. The rate determination module 302 determines the target self-discharge rate of the battery under test. The screening module 303 determines the battery under test to be qualified if the target self-discharge rate falls within both the first and second screening ranges; otherwise, it determines the battery to be unqualified. By changing the method of determining the first and second screening ranges, the screening accuracy of the first and second screening ranges is improved, avoiding multi-stage self-discharge screening of the battery, thereby reducing screening time while ensuring screening accuracy.

[0121] This application also provides an electronic device that integrates any of the self-discharge screening devices provided in this application, the electronic device comprising: One or more processors; Memory; and One or more applications, wherein the one or more applications are stored in the memory and configured to be executed by the processor as described in any of the embodiments of the self-discharge screening method above.

[0122] This application also provides an electronic device that integrates any of the self-discharge screening devices provided in this application. For example... Figure 7 As shown, it illustrates a structural schematic diagram of the electronic device involved in the embodiments of this application, specifically: The electronic device may include components such as a processor 401 with one or more processing cores, a memory 402 with one or more computer-readable storage media, a power supply 403, and an input unit 404. Those skilled in the art will understand that... Figure 7 The electronic device structure shown does not constitute a limitation on the electronic device and may include more or fewer components than shown, or combine certain components, or have different component arrangements. Wherein: The processor 401 is the control center of the electronic device. It connects various parts of the electronic device via various interfaces and lines. By running or executing software programs and / or modules stored in the memory 402, and by calling data stored in the memory 402, it performs various functions and processes data, thereby providing overall monitoring of the electronic device. Optionally, the processor 401 may include one or more processing cores; preferably, the processor 401 may integrate an application processor and a modem processor, wherein the application processor mainly handles the operating system, user interface, and applications, and the modem processor mainly handles wireless communication. It is understood that the modem processor may not be integrated into the processor 401.

[0123] The memory 402 can be used to store software programs and modules. The processor 401 executes various functional applications and data processing by running the software programs and modules stored in the memory 402. The memory 402 may mainly include a program storage area and a data storage area. The program storage area may store the operating system, at least one application program required for a function (such as an alert function), etc.; the data storage area may store data created based on the use of the electronic device, etc. In addition, the memory 402 may include high-speed random access memory, and may also include non-volatile memory, such as at least one disk storage device, flash memory device, or other volatile solid-state storage device. Accordingly, the memory 402 may also include a memory controller to provide the processor 401 with access to the memory 402.

[0124] The electronic device also includes a power supply 403 that supplies power to the various components. Preferably, the power supply 403 can be logically connected to the processor 401 through a power management system, thereby enabling functions such as charging, discharging, and power consumption management through the power management system. The power supply 403 may also include one or more DC or AC power supplies, recharging systems, power fault detection circuits, power converters or inverters, power status indicators, and other arbitrary components.

[0125] The electronic device may also include an input unit 404, which can be used to receive input digital or character information, and generate keyboard, mouse, joystick, optical or trackball signal inputs related to user settings and function control.

[0126] Although not shown, the electronic device may also include a display unit, etc., which will not be described in detail here. Specifically, in this embodiment, the processor 401 in the electronic device loads the executable files corresponding to the processes of one or more applications into the memory 402 according to the following instructions, and the processor 401 runs the applications stored in the memory 402 to realize various functions, as follows: A first screening range and a second screening range are obtained for screening the batteries to be tested. The first screening range is used to screen the batteries for self-discharge rate and is determined based on the target mapping relationship between the battery's state of charge and the battery's differential voltage. The second screening range is used to screen the batteries for self-discharge rate consistency and is determined based on the battery's target battery association information. Determine the target self-discharge rate of the battery under test; If the target self-discharge rate is within the first screening range and the second screening range, the battery under test is determined to be qualified; otherwise, the battery under test is determined to be unqualified.

[0127] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be performed by instructions, or by instructions controlling related hardware. These instructions can be stored in a computer-readable storage medium and loaded and executed by a processor.

[0128] Therefore, embodiments of this application provide a computer-readable storage medium, which may include: read-only memory (ROM), random access memory (RAM), a magnetic disk, or an optical disk, etc. A computer program is stored thereon, which is loaded by a processor to execute the steps in any of the self-discharge screening methods provided in embodiments of this application. For example, the computer program loaded by the processor can execute the following steps: A first screening range and a second screening range are obtained for screening the batteries to be tested. The first screening range is used to screen the batteries for self-discharge rate and is determined based on the target mapping relationship between the battery's state of charge and the battery's differential voltage. The second screening range is used to screen the batteries for self-discharge rate consistency and is determined based on the battery's target battery association information. Determine the target self-discharge rate of the battery under test; If the target self-discharge rate is within the first screening range and the second screening range, the battery under test is determined to be qualified; otherwise, the battery under test is determined to be unqualified.

[0129] This application also provides a computer program product, including a computer program / instructions, which, when executed by a processor, are used to perform the steps in any of the self-discharge screening methods provided in the application embodiments.

[0130] 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 detailed descriptions of other embodiments above, which will not be repeated here.

[0131] In practice, each of the above units or structures can be implemented as an independent entity or can be arbitrarily combined to be implemented as the same or several entities. For the specific implementation of each of the above units or structures, please refer to the previous method embodiments, which will not be repeated here.

[0132] The embodiments of the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. 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 the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for screening the self-discharge of a battery, characterized in that, The method includes: A first screening range and a second screening range are obtained for screening the batteries to be tested. The first screening range is used to screen the batteries for self-discharge rate and is determined based on the target mapping relationship between the battery's state of charge and the battery's differential voltage. The second screening range is used to screen the batteries for self-discharge rate consistency and is determined based on the battery's target battery association information. Determine the target self-discharge rate of the battery under test; If the target self-discharge rate is within the first screening range and the second screening range, the battery under test is determined to be qualified; otherwise, the battery under test is determined to be unqualified.

2. The battery self-discharge screening method according to claim 1, characterized in that, The methods for determining the first screening range include: From multiple mapping relationships between the state of charge of the battery and the differential voltage of the battery, determine the target mapping relationship that matches the battery under test; In the target mapping relationship, each two adjacent states of charge other than the target state of charge are determined, as well as the differential voltage corresponding to each adjacent state of charge, wherein the target state of charge is used to indicate a state of charge value that is less than a preset state of charge value. Based on the differential voltage corresponding to each of the adjacent states of charge, the voltage drop ratio of each of the adjacent states of charge is determined, so as to determine the first voltage based on the target voltage drop ratio among the voltage drop ratios. The initial voltage is determined to be the final voltage of the first sample battery after it has been left to stand for a first time, and the initial voltage is set as the first voltage. The first screening range is determined based on the first voltage, the end voltage, and the first duration.

3. The battery self-discharge screening method according to claim 2, characterized in that, The steps for constructing each of the aforementioned mapping relationships include: Determine the target battery capacity of the second sample battery in a fully charged state, and based on the target battery capacity, determine the number of constant-capacity discharges required for the second sample battery to be discharged at constant capacity per unit battery capacity; Determine the second voltage of the second sample battery after it has been left to stand for a second time in a fully charged state; The second sample battery is subjected to constant-capacity discharge to reduce its capacity from the first battery capacity to the second battery capacity. The third voltage of the second sample battery after being left to stand for the second time is then determined. The first battery capacity is the battery capacity before this constant-capacity discharge, and the second battery capacity is the battery capacity to be achieved after this constant-capacity discharge. The differential voltage determined based on the second voltage and the third voltage is correlated with the state of charge determined based on the first battery capacity and the target battery capacity; The number of constant-capacity discharges is decremented so that, if the number of constant-capacity discharges is not zero, the second battery capacity is used as the new first battery capacity, the third voltage is used as the new second voltage, and the step of constant-capacity discharge of the second sample battery is returned to be executed; or, if the number of constant-capacity discharges is zero, a mapping relationship is determined based on the associated differential voltage and the state of charge.

4. The battery self-discharge screening method according to claim 3, characterized in that, The target battery capacity is determined based on a first constant current method, which includes a 0.2C constant current method. The constant-capacity discharge is achieved based on a second constant current method, which includes a 0.01C constant current method.

5. The battery self-discharge screening method according to claim 1, characterized in that, The methods for determining the second screening range include: From multiple battery association information, determine the target battery association information that matches the battery under test; Based on the first self-discharge rate information of the target battery that is matched with the battery under test, a first screening index value and a first self-discharge rate deviation value are determined. The second screening range is determined based on the first self-discharge rate deviation value and the product of the screening coefficient corresponding to the target battery association information and the first screening index value.

6. The battery self-discharge screening method according to claim 5, characterized in that, The method for determining each of the battery-related information includes: Determine the second self-discharge rate information of the third sample battery after it has been left to stand for a third period of time; Based on the second self-discharge rate information, determine the second screening index value and the second self-discharge rate deviation value; The preset second screening range is determined based on the second self-discharge rate deviation value and the product between the preset screening coefficient corresponding to the third sample battery and the second screening index value. The third sample battery is filtered through the preset second filtering range to obtain the filtering result, and the battery association information of the third sample battery under the preset filtering coefficient is determined based on the filtering result.

7. The battery self-discharge screening method according to claim 6, characterized in that, The battery association information includes at least one of the following: the voltage difference of qualified sample batteries in the third sample battery, the first proportion of batteries in the third sample battery that were mistakenly judged as qualified sample batteries, the second proportion of batteries in the third sample battery that reached the preset quality standard, and the target probability that all batteries in the same batch of the third sample battery reached the preset quality standard. When the battery association information includes the pressure difference and the first percentage, the target battery association information is the battery association information with the smallest pressure difference and the first percentage; When the battery association information includes the second percentage and the target probability, the target battery association information is the battery association information with the highest second percentage and the highest target probability.

8. The self-discharge screening method for batteries according to any one of claims 1 to 7, characterized in that, Determining the target self-discharge rate of the battery under test includes: The battery under test after formation is subjected to a preset charge and discharge process until the voltage of the battery under test reaches the formation end voltage. Determine the fourth voltage of the battery under test after it has been left to stand for a fourth time, and the fifth voltage of the battery under test after it has been left to stand for a fifth time, wherein the fourth time is determined based on the formation end voltage and the correspondence between the preset fourth time and the preset formation end voltage; The target self-discharge rate of the battery under test is determined based on the fourth voltage, the fifth voltage, and the fifth duration.

9. The battery self-discharge screening method according to claim 8, characterized in that, The methods for determining the correspondence between the preset fourth duration and the preset formation end voltage include: The fourth sample battery after formation is subjected to a preset charge and discharge process until the voltage of the fourth sample battery reaches the preset formation end voltage. The preset formation end voltage is determined based on the preset fourth voltage, and the voltage difference between the preset formation end voltage and the preset fourth voltage is not greater than the preset voltage difference. Determine the sixth voltage of the fourth sample battery after it has been left to stand for a preset time, and update the cumulative standing time of the fourth sample battery. If the voltage difference between the sixth voltage and the preset fourth voltage is greater than the voltage difference threshold, return to the step of determining the sixth voltage of the fourth sample battery after it has been left to stand for a preset time, until the voltage difference between the sixth voltage and the preset fourth voltage is not greater than the voltage difference threshold. The cumulative resting time is used as the preset fourth duration, and a correspondence is established between the preset fourth duration and the preset formation end voltage.

10. An electronic device, characterized in that, It includes a memory and a processor; the memory stores an application program, and the processor runs the application program within the memory to perform the steps in the self-discharge screening method for batteries according to any one of claims 1 to 9.

11. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that is executed by a processor to implement the steps of the self-discharge screening method for a battery according to any one of claims 1 to 9.

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