Self-discharge detection method, detection device thereof and detection system thereof

Abstract

The application discloses a self-discharge detection method, a detection device thereof and a detection system thereof. The detection method comprises the following steps: connecting a current meter to each of a plurality of parallelly connected to-be-detected batteries; obtaining the current reading of each current meter as a detection value when a preset detection node is reached; judging whether the detection value meets a preset detection standard; if yes, determining that the to-be-detected battery connected with the current meter is a normal self-discharge battery; and if no, determining that the to-be-detected battery connected with the current meter is an abnormal self-discharge battery. Compared with a traditional voltage drop testing mode, the self-discharge detection time of the battery can be effectively shortened.

Description

Technical Field

[0001] This application relates to the field of battery self-discharge characteristic detection, specifically to a self-discharge detection method, its detection device, and its detection system. Background Technology

[0002] Due to limitations in process scale, technological level, and individual cell voltage, current power battery energy storage systems used in large equipment such as electric vehicles are typically composed of a series of batteries connected in series or parallel. To avoid the energy bottleneck effect, high requirements are placed on the self-discharge consistency of batteries within the same power battery energy storage system.

[0003] Therefore, screening out batteries with abnormal self-discharge is a crucial step in the manufacturing process of power battery energy storage systems. Currently, the commonly used screening method is to detect the battery's K-value (i.e., the voltage drop of the battery per unit time). However, this method has drawbacks such as being time-consuming and cannot adequately meet the needs of screening for self-discharge abnormalities in existing large-capacity batteries. Summary of the Invention

[0004] In view of the above problems, this application provides a self-discharge detection method, its detection device and detection system, which can effectively overcome at least some of the defects of traditional detection methods.

[0005] Firstly, this application provides a self-discharge detection method. The self-discharge detection method includes: connecting an ammeter to each of a plurality of parallel-connected batteries under test; acquiring the current reading of each ammeter as a detection value when a preset detection node is reached; determining whether the detection value meets a preset detection standard; if yes, determining that the battery under test connected to the ammeter is a battery with normal self-discharge; if no, determining that the battery under test connected to the ammeter is a battery with abnormal self-discharge.

[0006] In the technical solution of this application embodiment, the voltage difference between the batteries under test is indirectly detected by detecting the current reading of the parallel-connected batteries at the detection node, thereby screening for abnormal battery self-discharge. Compared with the traditional method of testing voltage drop, it has higher resolution and can effectively shorten the time required for battery self-discharge detection.

[0007] In some embodiments, the step of obtaining the current reading of each ammeter as a detection value when a preset detection node is reached specifically includes: obtaining the current reading of each ammeter as a detection value when the ammeter connection time reaches a preset time. The above technical solution provides a method for determining the detection node by setting an appropriate ammeter connection time. This method of determining the detection node is easy to implement and simple to operate.

[0008] In some embodiments, the step of obtaining the current reading of each ammeter as a detection value when a preset detection node is reached specifically includes: recording the change of the current reading of each ammeter over time; and obtaining the current reading of each ammeter as a detection value when the derivative of the change of the current readings of all ammeters with respect to time is within a preset numerical range; wherein the preset numerical range is a numerical range formed with zero as a reference. The above technical solution provides a method for determining the detection node by the change of the current readings of the ammeters. This method of determining the detection node ensures that the leakage current of each parallel-connected battery under test has reached a stable state, and has high accuracy and resolution.

[0009] In some embodiments, the step of connecting each of the plurality of batteries under test connected in parallel to an ammeter specifically includes: connecting the negative terminals of the plurality of batteries under test through wires, and connecting an ammeter to the positive terminal of each battery under test; wherein, when current flows out from the positive terminal of the battery under test, the current reading of the ammeter is positive. The step of determining whether the detected value meets a preset detection standard specifically includes: determining that the detected value meets the preset detection standard when the detected value is greater than zero; determining that the detected value meets the preset detection standard when the detected value is less than zero and its absolute value is less than a preset current threshold; and determining that the detected value does not meet the preset detection standard when the detected value is less than zero and its absolute value is greater than or equal to the preset current threshold.

[0010] The technical solution of this application provides a specific connection method for the ammeter and a specific definition of the current reading, as well as a corresponding method for judging the detection value. Based on the judgment method, batteries with abnormal self-discharge can be easily and quickly screened out by means of the current reading.

[0011] In some embodiments, the self-discharge detection method further includes the following steps: performing voltage drop tests on several sample batteries to determine the self-discharge rate of each sample battery; connecting several sample batteries in parallel and connecting an ammeter to each sample battery; acquiring the current reading of each ammeter when a preset detection node is reached; identifying a sample battery with a self-discharge rate identical to a preset self-discharge rate standard as a reference battery among the several sample batteries; and determining the absolute value of the current reading of the ammeter connected to the reference battery as a current threshold. The above technical solution provides a specific method for determining the current threshold using the test results of sample batteries and a self-discharge rate standard. The detection standard obtained in this way can be reused in the self-discharge anomaly detection of the same batch of batteries, effectively shortening the detection time.

[0012] In some embodiments, the self-discharge detection method further includes the following steps: acquiring detection values ​​of a plurality of tested batteries; statistically analyzing the distribution of detection values ​​of the plurality of tested batteries; and determining, in the distribution, the detection value whose frequency is the same as the historical self-discharge anomaly rate as the current threshold. The above technical solution provides a specific method for determining the current threshold using historical battery detection data. The detection standard obtained in this way reflects the overall situation in the battery production process and can provide an accurate detection standard when a large number of batteries are produced.

[0013] In some embodiments, before connecting an ammeter to each of the several parallel-connected batteries under test, the self-discharge detection method further includes the following step: connecting the several batteries under test in parallel and performing voltage equalization. In the above technical solution, performing voltage equalization before detecting leakage current ensures that each battery under test is in the same initial state, which helps improve the accuracy of the battery self-discharge detection results.

[0014] Secondly, this application provides a self-discharge detection device. The self-discharge detection device includes: a current acquisition module for acquiring the current reading of an ammeter connected to each battery under test; a detection module for determining whether a preset detection node has been reached; and a judgment module for determining whether the detection value meets a preset detection standard. If yes, the battery under test connected to the ammeter is determined to be a battery with normal self-discharge; otherwise, the battery under test connected to the ammeter is determined to be a battery with abnormal self-discharge. Several batteries under test are connected in parallel; the detection value is the current reading of the ammeter when the preset detection node is reached.

[0015] In the technical solution of this application embodiment, the detection device uses the leakage current present in the battery under test at the detection node as the screening criterion for battery self-discharge anomalies. Compared with the traditional method of testing voltage drop, leakage current can more quickly reflect the differences in battery self-discharge characteristics, thereby effectively shortening the time required for battery self-discharge detection.

[0016] Thirdly, this application provides an electronic device. The electronic device includes: a processor and a processor communicatively connected to the processor; a memory storing computer program instructions, which, when invoked by the processor, cause the processor to execute the self-discharge detection method as described above.

[0017] In the technical solution of this application embodiment, the electronic device uses the leakage current present in the battery under test at the detection node as a screening criterion for battery self-discharge anomalies. Compared with the traditional method of testing voltage drop, leakage current can more quickly reflect the differences in battery self-discharge characteristics, thereby effectively shortening the time required for battery self-discharge detection.

[0018] Fourthly, this application provides a non-volatile computer storage medium. This non-volatile computer storage medium stores computer program instructions, which, when invoked by a processor, execute the self-discharge detection method described above.

[0019] In the technical solution of this application embodiment, the leakage current present in the battery under test at the detection node is used as the screening criterion for battery self-discharge anomalies. Compared with the traditional method of testing voltage drop, leakage current can more quickly reflect the differences in battery self-discharge characteristics, thereby effectively shortening the time required for battery self-discharge detection.

[0020] Fifthly, this application provides a self-discharge detection system. The self-discharge detection system includes a leakage current detection device and a control device. The leakage current detection device includes a plurality of ammeters and a connection device for connecting the batteries under test in parallel, with each ammeter connected to one battery under test. The control device is configured to execute the self-discharge detection method described above to screen out batteries with abnormal self-discharge among the plurality of batteries under test.

[0021] In the technical solution of this application embodiment, the leakage current present in the battery under test at the detection node is used as the screening criterion for battery self-discharge anomalies. Compared with the traditional method of testing voltage drop, leakage current can more quickly reflect the differences in battery self-discharge characteristics, thereby effectively shortening the time required for battery self-discharge detection.

[0022] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0023] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0024] Figure 1 This is a schematic diagram of the structure of a self-discharge detection system according to some embodiments of this application;

[0025] Figure 2 This is a flowchart of a self-discharge detection method according to some embodiments of this application;

[0026] Figure 3This is a schematic diagram illustrating the change of current reading over time in some embodiments of this application, showing the change of current reading over time in the battery under test after voltage equalization;

[0027] Figure 4 The flowchart of a method for determining whether a detection node has been reached according to some embodiments of this application illustrates a method for determining a detection node based on the differential result of the current reading;

[0028] Figure 5 The flowchart of a method for determining whether a detection node has been reached, according to other embodiments of this application, illustrates a method for determining a detection node based on the detection time of the connected ammeter;

[0029] Figure 6 The flowchart of a method for generating a current threshold according to some embodiments of this application illustrates a method for determining a current threshold based on the detection results of a sample battery.

[0030] Figure 7 This is a flowchart of a method for generating a current threshold according to other embodiments of this application, illustrating a method for determining a current threshold using historical detection data;

[0031] Figure 8 This is a flowchart of a self-discharge detection method according to some other embodiments of this application;

[0032] Figure 9 This is a functional block diagram of a self-discharge detection device according to some embodiments of this application;

[0033] Figure 10 This is a functional block diagram of a self-discharge detection device according to other embodiments of this application;

[0034] Figure 11 This is a schematic diagram of an electronic device according to some embodiments of this application. Detailed Implementation

[0035] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0037] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0038] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0039] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0040] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0041] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0042] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0043] Currently, typical methods for screening for abnormal battery self-discharge mainly involve detecting the K-value (i.e., the voltage drop of a battery per unit time) of multiple batteries. Then, batteries with K-values ​​significantly higher than normal, or whose K-values ​​differ significantly from those of other batteries, are identified as having abnormal self-discharge.

[0044] The applicant notes that testing the K-value of a battery is time-consuming. For example, to ensure that all batteries have the same starting voltage during testing, voltage equalization is required for all batteries under test. In particular, for large-capacity power batteries, the voltage drop generated in a short period of time is very small and difficult to detect using instruments. The voltage drop can only be accurately detected after the battery has been left to stand for a considerable period of time.

[0045] To address the issue of time-consuming self-discharge detection, the applicant provides a technical solution for detecting battery self-discharge anomalies based on battery leakage current. This solution connects the batteries to be tested in parallel and performs detection based on the current reading at the detection node. Compared to methods that detect voltage drop, this solution offers higher resolution and significantly reduces testing time because it distinguishes the relative magnitude of voltage drops between different batteries by detecting current.

[0046] To fully illustrate the specific application scenarios of this application, the following description uses 16 batteries connected in parallel as an example. Of course, those skilled in the art will understand that, based on the same principles and concepts, the self-discharge detection system of this application embodiment can also be applied to the detection of self-discharge anomalies in other numbers and types of batteries.

[0047] Please see Figure 1 , Figure 1 This is a schematic diagram of the structure of a self-discharge detection system according to some embodiments of this application. The self-discharge detection system includes a leakage current detection device 110 and a control device 120.

[0048] Among them, the leakage current detection device 110 is a data acquisition device used to connect all the batteries under test B in parallel and to collect the leakage current of each branch where the battery under test B is located.

[0049] In some embodiments, depending on the function to be performed, the leakage current detection device 110 may include a connection device 111 and a plurality of ammeters 112. The connection device 111 may be implemented by wires or any other suitable type of electrical connection component, as long as it can enable parallel connection between multiple batteries.

[0050] The ammeter 112 can be any suitable type of current sensing instrument, as long as it has sufficient current sensing accuracy. In some embodiments, a high-precision ammeter with the lowest possible internal resistance can be selected. A corresponding ammeter 112 can be installed on each branch containing the battery B under test to detect the leakage current of the battery B under test on that branch. For example, as... Figure 1 As shown, there are 16 ammeters 112 corresponding to the 16 batteries connected in parallel.

[0051] In some embodiments, ammeter 112 can be connected between the positive terminal of the battery under test B and the parallel connection node N of the battery under test B. Thus, when current flows out from the positive terminal of the battery under test B, the current reading of ammeter 112 is positive, and when current flows in from the parallel connection node N, the current reading of ammeter 112 is negative.

[0052] Of course, the position of the ammeter 112 can be adjusted according to actual needs to provide corresponding current readings, and is not limited to this. Figure 1 As shown.

[0053] The control device 120 can be an electronic computing device with logic operation functions, including but not limited to servers or industrial computers. It can establish a communication connection with the leakage current detection device 110 through wired or wireless means, thereby receiving the current readings collected by the leakage current detection device 110, and determining whether the battery under test B has an abnormal self-discharge.

[0054] In operation, multiple batteries B under test are connected in parallel via leakage current detection device 110 (e.g., Figure 1 The system displays 16 batteries under test and provides the leakage current of the branch where each battery B is located. Based on time and current readings provided by the leakage current detection device 110, the control device 120 determines whether a pre-set detection node has been reached. If the detection node has been reached, the control device 120 determines whether the current readings obtained by the leakage current detection device 110 meet pre-set detection standards (e.g., a preset current threshold), and identifies the battery under test whose current readings do not meet the preset detection standards as a self-discharge abnormal battery.

[0055] One advantage of this application's embodiments is that, since the voltage drop of the battery under test changes extremely little in a short time, it can only be effectively detected and identified after a relatively long period of rest. Therefore, the detection method of screening self-discharge abnormal batteries by detecting the current in the branch where the parallel-connected battery under test is located can effectively shorten the detection time and improve the resolution compared to measuring the voltage drop of the battery under test.

[0056] According to some embodiments of this application, Figure 2 This is a flowchart illustrating a self-discharge detection method according to some embodiments of this application. This self-discharge detection method can be executed by the aforementioned self-discharge detection system. Please refer to... Figure 2 The self-discharge detection method includes:

[0057] S201. Connect an ammeter to each of the several parallel-connected batteries under test.

[0058] "Battery under test" refers to an energy storage component that has been manufactured and requires self-discharge anomaly detection to ensure the consistency of its self-discharge characteristics. It can be a single cell or a battery assembly composed of multiple cells.

[0059] The "connected ammeter" is connected to the branch where each battery under test is located, and can reflect the relative magnitude of the leakage current of each battery under test. Specifically, any suitable connection method can be selected according to the actual needs, for example... Figure 1 The ammeter connection method is shown.

[0060] S202. When the preset detection node is reached, the current reading of each ammeter is obtained as the detection value.

[0061] Here, "detection node" refers to a time point determined based on one or more detection or measurement benchmarks. It can be preset by technicians according to actual needs, as long as there is a sufficiently large difference between the multiple current readings at that time point.

[0062] In some embodiments, please refer to Figure 3 , Figure 3 This diagram illustrates the changes in current readings of 16 batteries under test after voltage equalization, as provided in an embodiment of this application. After voltage equalization, the voltages of each battery under test will remain consistent in the initial stage. Therefore, in Figure 3 Initially, the ammeter readings are zero. As the test time increases, the voltages of the individual batteries will differ due to variations in their self-discharge. Consequently, the corresponding current readings will begin to differ over time. Eventually, after a certain test period, the voltage differences between the batteries will stabilize, and the corresponding current readings will also reach a steady-state.

[0063] Therefore, from Figure 3 The changes in current readings show that a suitable detection node can be selected to distinguish between batteries with different self-discharge characteristics.

[0064] S203. Determine whether the detection value meets the preset detection standard. If yes, proceed to step S204; otherwise, proceed to step S205.

[0065] Among them, the "testing standard" is a screening standard determined by technicians based on the method of obtaining the test values ​​and the test results of the same batch or the same type of batteries. It is used to determine whether the current reading of the battery under test is closer to that of a battery with abnormal self-discharge or a battery with normal self-discharge.

[0066] S204. Confirm that the battery under test connected to the ammeter is a normal self-discharge battery.

[0067] In this case, if the preset testing standards are met, it indicates that, based on existing historical experience, the battery under test is highly likely to be a battery with normal self-discharge and can pass the test.

[0068] S205. Determine that the battery under test connected to the ammeter is a self-discharge abnormal battery.

[0069] In cases where the preset testing standards are not met, it indicates that, based on existing historical experience, the leakage current of the battery under test is significantly excessive, indicating an abnormal self-discharge.

[0070] One advantage of this application is that it uses the leakage current present in the battery under test at the detection node as a screening criterion for battery self-discharge anomalies. Compared with the traditional method of testing voltage drop, leakage current can more quickly reflect the differences in battery self-discharge characteristics, thereby effectively shortening the time required for battery self-discharge detection.

[0071] In some embodiments, step S202 may specifically include: when the connection time of the ammeter reaches a preset time, acquiring the current reading of each ammeter as a detection value.

[0072] This preset time is set by technicians based on changes in the current reading. For example, such as... Figure 3 As shown, the preset time is 10 hours after the current reading enters a stable period. Of course, the preset time can be adjusted according to different actual situations. For example, when high precision testing is not required, 2-4 hours after the current reading begins to change can be selected.

[0073] One of the advantages of this application's embodiments is that determining the detection node by setting an appropriate ammeter connection time is easy to implement and simple to operate.

[0074] According to some embodiments of this application, optionally, please refer to Figure 4 , Figure 4A flowchart illustrating the method for determining detection nodes provided in this application embodiment. Step S202 specifically includes:

[0075] S2021. Record the change in current reading of each ammeter over time.

[0076] The "change of current reading over time" refers to the current readings collected at different times after the battery under test is connected to the testing equipment. It can be represented in any suitable form, such as a current-time curve with time on the x-axis and current reading on the y-axis.

[0077] S2022. Calculate the differential result of the change in the ammeter current reading with respect to time.

[0078] The "differential result" refers to the numerical result obtained after differentiating the aforementioned current-time curve. The specific differential calculation method is well known to those skilled in the art and will not be elaborated upon further.

[0079] S2023. Determine whether the differential results of all ammeters are within the preset value range. If yes, proceed to step S2024; otherwise, proceed to step S2025.

[0080] The preset numerical range refers to a range of values ​​based on zero. In other words, step S2023 is used to determine whether the differential results of all ammeters are approximately equal to zero. Of course, the specific range can be determined by technicians according to the actual needs.

[0081] S2024. Obtain the current reading of each ammeter as the detection value.

[0082] As those skilled in the art will understand, the aforementioned differential results can actually be used to measure the rate of change of current readings. When the differential results of all ammeters are approximately zero, it indicates that the rate of change of current readings of each ammeter is essentially zero. Figure 3 The indicator shows a stable period. Therefore, it can be determined that we are now at the detection point, and the current reading can be obtained as the detection value.

[0083] S2025. Determine that the preset detection node has not yet been reached.

[0084] If the current reading still shows a rate of change, it indicates that the leakage current of the battery under test still exists and has not yet reached a stable period, thus not reaching the detection node.

[0085] One advantage of this application embodiment is that the method of determining the detection node by the change of the current reading of the ammeter can ensure that the leakage current of each parallel-connected battery under test has reached a stable state, which has high accuracy and resolution.

[0086] According to some embodiments of this application, optionally, please refer to Figure 5 , Figure 5 This is a flowchart illustrating a method for determining whether a detection value meets a preset detection standard, as provided in an embodiment of this application. When employing... Figure 1 As shown, when the negative terminals of multiple batteries under test are connected by wires, and the positive terminal of each battery under test is connected to an ammeter, step S203 specifically includes the following steps:

[0087] S2031. Determine whether the detected value is greater than zero. If yes, proceed to step S2032; otherwise, proceed to step S2033.

[0088] Specifically, the ammeter reading is set to positive when current flows from the positive terminal of the battery under test. This means that when using... Figure 1 With the connection shown, a positive current reading indicates that, in the current state, the voltage of the battery under test is greater than the voltage at the parallel node. This suggests that the battery under test should have a low self-discharge rate.

[0089] S2032. Determine that the test value meets the preset test standard.

[0090] S2033. Determine whether the absolute value of the detected value is greater than or equal to the preset current threshold. If yes, proceed to step S2034; otherwise, proceed to step S2032.

[0091] When the current reading is negative, it indicates that the voltage of the battery under test is less than the voltage at the parallel node in the current state. Furthermore, the larger the absolute value of the current reading, the greater the voltage difference between the battery under test and the parallel node, and the more severe the self-discharge. Therefore, by setting an appropriate current threshold, it can be determined whether the self-discharge level of the battery under test is too high and should be classified as an abnormal self-discharge battery.

[0092] S2034. Determine that the detected value does not meet the preset detection standard.

[0093] One advantage of this application is that, based on the specific connection method of the ammeter and the specific definition of the current reading, a corresponding detection value judgment method is provided, which can easily and quickly screen out batteries with self-discharge abnormalities.

[0094] It should be noted that, based on the detection value judgment principle disclosed in the embodiments of this application, those skilled in the art can also adjust, replace, or delete one or more judgment steps in the detection standard according to different actual situations (such as changes in the connection position of the ammeter), and are not limited to the embodiments of this application. Figure 5 As shown.

[0095] According to some embodiments of this application, optionally, please refer to Figure 6 , Figure 6 A flowchart illustrating a method for determining a current threshold provided in an embodiment of this application. The method for determining a current threshold specifically includes:

[0096] S601. Perform voltage drop tests on several sample batteries to determine the self-discharge rate of each sample battery.

[0097] The "self-discharge rate" refers to the voltage drop of a battery under quiescent conditions per unit time. It can be obtained through traditional voltage drop testing methods, including voltage equalization and testing after prolonged quiescence. The specific methods for voltage drop testing are well-known to those skilled in the art and will not be elaborated upon here.

[0098] S602. Connect several sample batteries in parallel and connect an ammeter to each sample battery.

[0099] Here, "sample battery" refers to a battery with similar characteristics to the battery under test, such as batteries of the same type produced in the same batch or on the same production line. It is understood that sample batteries are representative and can be considered as samples for sampling and testing of the batteries under test; therefore, they are referred to as "sample batteries" in this embodiment.

[0100] S603. When the preset detection node is reached, obtain the current reading of each ammeter.

[0101] In this process, the same self-discharge detection method as the test battery was used for each sample battery to obtain the current reading when it reached the detection node.

[0102] S604. Among several sample batteries, the sample battery with the same self-discharge rate as the preset self-discharge rate standard is selected as the reference battery.

[0103] The "self-discharge rate standard" is a standard value determined by technicians based on actual needs. Its specific value can be determined according to the requirements of the situation (e.g., production targets required by the customer).

[0104] It should be noted that the above "same" means that the self-discharge rate of the sample battery is roughly the same as the self-discharge rate standard, not absolutely the same. The difference between the two is allowed to fluctuate within a specific percentage range, such as 1%.

[0105] S605. Determine that the absolute value of the current reading of the ammeter connected to the reference battery is the current threshold.

[0106] Since the sample battery underwent voltage drop testing and the self-discharge detection method provided in this application embodiment, both the self-discharge rate and the detected value of the sample battery are known. Therefore, a correspondence between the self-discharge rate and the detected value can be established using the sample battery, thereby determining the corresponding current threshold based on a preset self-discharge rate for screening for self-discharge anomalies in the battery under test.

[0107] One advantage of this application is that it provides a specific method for determining a current threshold based on a self-discharge rate standard. This current threshold can be reused in the detection of self-discharge anomalies in the same batch of batteries, thereby effectively shortening the detection time.

[0108] According to some embodiments of this application, optionally, please refer to Figure 7 , Figure 7 A flowchart illustrating a method for determining a current threshold provided in other embodiments of this application. This method for determining a current threshold specifically includes:

[0109] S701, Obtain the detection values ​​of several tested batteries.

[0110] Here, "tested battery" refers to a battery that has undergone the self-discharge detection method provided in the above embodiments. In some embodiments, these existing detection values ​​can be recorded in a pre-set historical database for easy retrieval and retrieval.

[0111] S702. Statistically analyze the distribution of test values ​​for several tested batteries.

[0112] Here, "distribution" refers to the frequency of different detection values. It can be represented in any suitable way. For example, a graph with the detection value on the x-axis and the frequency of occurrence on the y-axis.

[0113] S703. In the distribution case, the detection value that has the same frequency of occurrence as the historical self-discharge anomaly rate is determined to be the current threshold.

[0114] The "historical self-discharge anomaly rate" refers to the probability of a battery exhibiting self-discharge anomalies, determined based on existing historical data. For example, it's the ratio of batteries with detected self-discharge anomalies to the total number of batteries produced on a production line over a relatively long period.

[0115] "Frequency of occurrence" can be obtained from the distribution data, which represents the proportion of times the detected value appears in the existing historical data.

[0116] One advantage of this application is that it provides a method for determining the current threshold using historical battery testing data. This results in a testing standard that reflects the overall situation during the battery production process and provides accurate testing standards when producing a large number of batteries.

[0117] According to some embodiments of this application, optionally, please refer to Figure 8 , Figure 8 A flowchart illustrating a self-discharge detection method provided in other embodiments of this application. Besides... Figure 2 In addition to the self-discharge detection steps shown, the self-discharge detection method also includes:

[0118] S200: Connect several batteries under test in parallel to perform voltage balancing.

[0119] "Voltage equalization" refers to a method of connecting the batteries under test in parallel for a sufficiently long period of time to ensure that the voltages of all the batteries under test are the same. This voltage equalization step is performed before step S201.

[0120] One advantage of this application embodiment is that, through the pre-performed voltage equalization step, it can be ensured that each battery under test is in the same initial state, which helps to improve the accuracy of battery self-discharge detection results.

[0121] The following provides several specific examples to fully illustrate the self-discharge detection method of this application and the specific implementation of each step of the self-discharge detection method.

[0122] Example 1:

[0123] 1) Potential equalization: Connect 16 fresh batteries to be tested in parallel for 12 hours to perform potential equalization.

[0124] 2) Connecting ammeters: Connect an ammeter to each battery connected in parallel. The ammeter can be selected with a current detection accuracy of ±1uA and an internal resistance of 50mΩ.

[0125] 3) Obtain the detection value: When the current reading of the ammeter reaches a stable state by determining the differential result of the current reading, obtain the current reading of each ammeter at this time as the detection value.

[0126] 4) Determine the current threshold: Perform voltage drop tests and the above detection steps on other batteries from the same batch to obtain their voltage drops and detection values. Then, based on the self-discharge rate requirement: batteries with a self-discharge rate above 0.02mV / h are considered to have abnormal self-discharge. Determine the detection value of the current threshold for batteries with a self-discharge rate of 0.02mV / h.

[0127] The step of determining the current threshold can be performed first, and the obtained current threshold can be pre-stored in a specific memory for the control device to call.

[0128] 5) Screening for Batteries with Abnormal Self-Discharge: If the detected value of the battery under test is greater than zero, the battery is determined to be a battery with normal self-discharge. If the detected value of the battery under test is less than zero, determine whether the absolute value of the detected value is greater than or equal to the current threshold determined in step 4). If yes, the battery is determined to be a battery with abnormal self-discharge; otherwise, the battery is determined to be a battery with normal self-discharge.

[0129] Example 2:

[0130] 1) Potential equalization: The 32 fresh batteries to be tested were connected in parallel for 18 hours to perform potential equalization.

[0131] 2) Connecting ammeters: Connect an ammeter to each battery connected in parallel. The ammeter can be selected with a current detection accuracy of ±1uA and an internal resistance of 100mΩ.

[0132] 3) Obtain the detection value: When the current reading of the ammeter reaches a stable state by determining the differential result of the current reading, obtain the current reading of each ammeter at this time as the detection value.

[0133] 4) Determine the current threshold: Conduct large-scale testing on the batteries produced on the production line to obtain the distribution of test values ​​for a large number of batteries, i.e., the frequency of different test values. Then, based on historical data, if the historical self-discharge anomaly rate of the same type of batteries produced on this production line is determined to be 0.1%, the test value corresponding to the probability of the test value occurring at 0.1% is determined to be the current threshold.

[0134] The step of determining the current threshold can be performed first, and the obtained current threshold can be pre-stored in a specific memory for the control device to call.

[0135] 5) Screening for Batteries with Abnormal Self-Discharge: If the detected value of the battery under test is greater than zero, the battery is determined to be a battery with normal self-discharge. If the detected value of the battery under test is less than zero, determine whether the absolute value of the detected value is greater than or equal to the current threshold determined in step 4). If yes, the battery is determined to be a battery with abnormal self-discharge; otherwise, the battery is determined to be a battery with normal self-discharge.

[0136] Example 3:

[0137] 1) Potential equalization: Connect 32 fresh batteries to be tested in parallel for 15 hours to perform potential equalization.

[0138] 2) Connecting ammeters: Connect an ammeter to each battery connected in parallel. The ammeter can be selected with a current detection accuracy of ±1uA and an internal resistance of 100mΩ.

[0139] 3) Obtain the test value: After 10 hours, obtain the current reading of each ammeter as the test value.

[0140] 4) Determine the current threshold: Conduct large-scale testing on the batteries produced on the production line to obtain the distribution of test values ​​for a large number of batteries, i.e., the frequency of different test values. Then, based on historical data, if the historical self-discharge anomaly rate of the same type of batteries produced on this production line is determined to be 0.1%, the test value corresponding to the probability of the test value occurring at 0.1% is determined to be the current threshold.

[0141] The step of determining the current threshold can be performed first, and the obtained current threshold can be pre-stored in a specific memory for the control device to call.

[0142] 5) Screening for Batteries with Abnormal Self-Discharge: If the detected value of the battery under test is greater than zero, the battery is determined to be a battery with normal self-discharge. If the detected value of the battery under test is less than zero, determine whether the absolute value of the detected value is greater than or equal to the current threshold determined in step 4). If yes, the battery is determined to be a battery with abnormal self-discharge; otherwise, the battery is determined to be a battery with normal self-discharge.

[0143] One advantage of this application's embodiments is that by indirectly obtaining the relative magnitude of the voltage drop of the batteries under test through detecting the current readings of the branches where each battery under test is connected in parallel, it is easier to distinguish subtle voltage changes between the batteries under test, and no long-term accumulation is required. This effectively reduces the time required to screen batteries with abnormal self-discharge.

[0144] According to some embodiments of this application, please refer to Figure 9 , Figure 9 This application describes a self-discharge detection device 900. The self-discharge detection device 900 includes: a current acquisition module 910, a detection module 920, and a judgment module 930.

[0145] The current acquisition module 910 acquires the current reading of each ammeter connected to the battery under test. The detection module 920 determines whether a preset detection node has been reached. The judgment module 930 determines whether the detection value meets a preset detection standard. If yes, the battery under test connected to the ammeter is determined to be a battery with normal self-discharge; otherwise, the battery under test connected to the ammeter is determined to be a battery with abnormal self-discharge. Several batteries under test are connected in parallel; the detection value is the current reading of the ammeter when the preset detection node is reached.

[0146] In operation, several batteries under test are connected in parallel, and each battery is connected to an ammeter. The current acquisition module 910 can acquire the current reading of each ammeter connected to the battery under test. The detection module 920 determines whether a preset detection node has been reached based on the detection time or the current reading. The judgment module 930, based on the judgment result of the detection module 920, determines whether the current reading at the detection node meets the preset detection standard, and filters out batteries with abnormal self-discharge according to the judgment result.

[0147] One advantage of this application's embodiments is that the detection device uses the leakage current of the battery under test as a screening criterion for abnormal battery self-discharge. Compared to the traditional method of testing voltage drop, leakage current can more quickly reflect differences in battery self-discharge characteristics, thereby effectively shortening the time required for battery self-discharge detection.

[0148] According to some embodiments of this application, optionally, the detection module 920 is specifically used to: acquire the current reading of each ammeter as a detection value when the connection time of the ammeter reaches a preset time. This preset time can be determined by a technician according to actual needs. This embodiment provides a method for determining the detection node by the length of the detection time, which is easy to implement and simple to operate.

[0149] According to some embodiments of this application, optionally, the detection module 920 is specifically used to: record the change of the current reading of each ammeter over time; and when the derivative of the change of the current reading of all ammeters with respect to time is within a preset numerical range, acquire the current reading of each ammeter as a detection value; wherein, the preset numerical range is a numerical range formed with zero as a reference.

[0150] In this embodiment, the detection node is determined by the differential result of the current reading of the ammeter changing over time. This ensures that the leakage current of each parallel-connected battery under test has reached a stable state, resulting in high accuracy and resolution.

[0151] According to some embodiments of this application, optionally, the judgment module 930 is specifically used to: determine that the detection value meets a preset detection standard when the detection value is greater than zero; determine that the detection value meets a preset detection standard when the detection value is less than zero and the absolute value is less than a preset current threshold; and determine that the detection value does not meet the preset detection standard when the detection value is less than zero and the absolute value is greater than or equal to a preset current threshold.

[0152] In this embodiment, the negative and positive terminals of several batteries under test are connected by wires, and an ammeter is connected between the positive terminal of each battery and the parallel connection node. When current flows out from the positive terminal of the battery under test, the ammeter reading is positive. This embodiment provides a specific method for screening batteries with abnormal self-discharge. Based on this screening method, batteries with abnormal self-discharge can be easily and quickly identified by measuring the current reading.

[0153] According to some embodiments of this application, optionally, please refer to Figure 10 , Figure 10 This application provides a self-discharge detection device according to another embodiment. This self-discharge detection device, in addition to... Figure 9 In addition to the functional modules shown, it also includes: a threshold setting module 940 for generating a current threshold as a detection standard.

[0154] Specifically, the threshold setting module 940 is used to: perform voltage drop tests on several sample batteries to determine the self-discharge rate of each sample battery; connect several sample batteries in parallel and connect an ammeter to each sample battery; when a preset detection node is reached, obtain the current reading of each ammeter; among several sample batteries, determine the sample battery whose self-discharge rate is the same as the preset self-discharge rate standard as the reference battery; and determine the absolute value of the current reading of the ammeter connected to the reference battery as the current threshold.

[0155] This embodiment provides a specific method for determining the current threshold using test results of sample batteries and a self-discharge rate standard. The resulting detection standard can be reused in the detection of self-discharge anomalies within the same batch of batteries.

[0156] According to some embodiments of this application, optionally, the threshold setting module 940 can also generate a current threshold based on historical detection data.

[0157] Specifically, the threshold setting module 940 is used to: acquire the detection values ​​of several tested batteries; statistically analyze the distribution of the detection values ​​of several tested batteries; and determine the detection value with the same frequency as the historical self-discharge abnormality rate as the current threshold value in the distribution.

[0158] In this embodiment, determining the current threshold using historical battery testing data reflects the overall situation during battery production. This provides a precise testing standard when producing a large number of batteries.

[0159] According to some embodiments of this application, optionally, please continue to refer to Figure 10 The self-discharge detection device may also include a voltage equalization module 950.

[0160] The voltage equalization module 950 is used to trigger several batteries under test to connect in parallel and perform voltage equalization for a preset time. The preset voltage equalization time can be set according to actual needs.

[0161] In this embodiment, voltage equalization is performed before detecting leakage current to ensure that each battery under test is in the same initial state, which helps to improve the accuracy of battery self-discharge detection results.

[0162] It should be noted that, in the embodiments of this application, the functional modules of the self-discharge detection device are divided according to the method steps to be performed. In some embodiments, one or more functional modules (such as a current acquisition module, a detection module, a judgment module, a threshold setting module, and a voltage equalization module) of the self-discharge detection device in the embodiments of this application may be split into more functional modules as needed to perform the corresponding method steps. In other embodiments, one or more functional modules of the battery swapping device in the embodiments of this application may be integrated into fewer functional modules to perform the corresponding method steps.

[0163] According to some embodiments of this application, please refer to Figure 11 , Figure 11 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. The electronic device can be a control device or any other suitable type of electronic computing platform for executing the above-described self-discharge detection method; its specific implementation is not limited herein.

[0164] The electronic device may include: a processor 1110, a communication interface 1120, a memory 1130, and a communication bus 1140.

[0165] The processor 1110, communication interface 1120, and memory 1130 communicate with each other via communication bus 1140. Communication interface 1120 is used for communication connections with other devices (e.g., an ammeter). The processor 1110 calls program 1150 to execute one or more method steps in the self-discharge detection method of the above embodiments or to implement one or more functional modules of the self-discharge detection device of the above embodiments. Specifically, program 1150 may include program code or computer operation instructions.

[0166] In this embodiment, depending on the type of hardware used, the processor 1110 may be a central processing unit, other general-purpose processors, digital signal processors, application-specific integrated circuits, off-the-shelf programmable gate arrays or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0167] The memory 1130 is used to store the program 1150. The memory 1130 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage.

[0168] This application also provides a computer-readable storage medium. This computer-readable storage medium can be a non-volatile computer-readable storage medium. This computer-readable storage medium stores a computer program.

[0169] When the computer program is executed by a processor, it implements one or more method steps in the self-discharge detection method of the above embodiments or implements one or more functional modules in the self-discharge detection device of the above embodiments. The complete computer program product is embodied on one or more computer-readable storage media (including but not limited to, disk storage, CD-ROM, optical storage, etc.) containing the computer program disclosed in the embodiments of this application.

[0170] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A self-discharge detection method, characterized in that, include: Connect an ammeter to each of the several batteries under test connected in parallel. When a preset detection node is reached, the current reading of each ammeter is obtained as the detection value. Determine whether the detected value meets the preset detection standard; If so, determine that the battery under test connected to the ammeter is a battery with normal self-discharge. If not, then the battery under test connected to the ammeter is determined to be a battery with abnormal self-discharge. The process involves connecting each of several parallel-connected batteries to an ammeter, specifically including: The negative terminals of several batteries under test are connected by wires, and an ammeter is connected to the positive terminal of each battery under test; wherein, when current flows out from the positive terminal of the battery under test, the current reading of the ammeter is positive; The determination of whether the detected value meets the preset detection standard specifically includes: When the detected value is greater than zero, it is determined that the detected value meets the preset detection standard; When the detected value is less than zero and the absolute value is less than a preset current threshold, the detected value is determined to meet the preset detection standard. When the detected value is less than zero and its absolute value is greater than or equal to a preset current threshold, it is determined that the detected value does not meet the preset detection standard. The method further includes: Voltage drop tests were performed on several sample batteries to determine the self-discharge rate of each sample battery. Several of the sample batteries are connected in parallel, and an ammeter is connected to each of the sample batteries; When the preset detection conditions are met, the current reading of each ammeter is obtained; Among the sample batteries, the sample battery with the same self-discharge rate as the preset self-discharge rate standard is selected as the reference battery. The absolute value of the current reading of the ammeter connected to the reference battery is determined to be the current threshold.

2. The self-discharge detection method according to claim 1, characterized in that, The step of acquiring the current reading of each ammeter as a detection value when a preset detection node is reached specifically includes: When the connection time of the ammeter reaches a preset time, the current reading of each ammeter is obtained as a detection value.

3. The self-discharge detection method according to claim 1, characterized in that, The step of acquiring the current reading of each ammeter as a detection value when a preset detection node is reached specifically includes: Record the change in the current reading of each ammeter over time; When the derivative of the current readings of all ammeters with respect to time is within a preset range, the current reading of each ammeter is obtained as the detection value. The preset numerical range is a range of values ​​based on zero.

4. The self-discharge detection method according to claim 1, characterized in that, The method further includes: Obtain the detection values ​​of several tested batteries; The distribution of the test values ​​of several of the tested batteries was statistically analyzed; In the aforementioned distribution, the detection value that has the same frequency of occurrence as the historical self-discharge anomaly rate is determined to be the current threshold.

5. The self-discharge detection method according to any one of claims 1-4, characterized in that, Before connecting an ammeter to each of the several parallel-connected batteries under test, the method further includes: Several of the batteries under test are connected in parallel to perform voltage balancing.

6. A self-discharge detection device, characterized in that, For performing the self-discharge detection method according to any one of claims 1-5, the self-discharge detection device comprises: The current acquisition module is used to acquire the current reading of each ammeter connected to the battery under test; The detection module is used to determine whether the preset detection node has been reached; The judgment module is used to determine whether the detection value meets the preset detection standard; if yes, it determines that the battery under test connected to the ammeter is a battery with normal self-discharge; if no, it determines that the battery under test connected to the ammeter is a battery with abnormal self-discharge. Among them, several of the batteries to be tested are connected in parallel, and the detection value is the current reading of the ammeter when a preset detection node is reached.

7. A non-volatile computer storage medium, characterized in that, The non-volatile computer storage medium stores computer program instructions so that when the computer program instructions are invoked by a processor, the self-discharge detection method as described in any one of claims 1-5 is executed.

8. An electronic device, characterized in that, include: A processor and a memory communicatively connected to the processor; the memory stores computer program instructions that, when invoked by the processor, cause the processor to execute the self-discharge detection method as described in any one of claims 1-7.

9. A self-discharge detection system, characterized in that, include: A leakage current detection device, comprising: a plurality of ammeters and a connection device for connecting the batteries under test in parallel, wherein each ammeter is connected to one battery under test; A control device configured to perform the self-discharge detection method as described in any one of claims 1-5, and to screen out batteries with abnormal self-discharge from a plurality of batteries to be tested.

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