Battery safety detection method, device, electronic device and storage medium

Abstract

The present application relates to a battery safety detection method, device, electronic device and storage medium. The method comprises: each time a triggering condition is detected, a preset charging process is used to charge the target object; wherein the preset charging process comprises a constant current charging stage and a constant voltage charging stage; the target object is one of a single cell, a battery module and a battery pack; the target object is detected according to the first charging amount in the constant current charging stage and the second charging amount in the constant voltage charging stage to obtain a safety detection result; the safety detection result is used to characterize whether the target object has an abnormal expansion force. The use of the present application can avoid many problems caused by the use of sensors, and can apply expansion force detection to battery modules and battery packs, thereby improving the safety of single cells, battery modules and battery packs.

Description

Technical Field

[0001] The present application relates to the technical field of battery safety detection, and in particular to a battery safety detection method, device, electronic device and storage medium. Background Art

[0002] With the development of new energy technologies, lithium batteries are used in various fields, such as new energy vehicles, intelligent robots, etc. During use, lithium batteries will undergo multiple side reactions such as the growth of the solid electrolyte interface SEI film at the negative electrode, the loss of positive electrode materials, and the loss of negative electrode materials, which will lead to irreversible loss of active lithium in lithium batteries, a decrease in life or capacity, and an increase in expansion force. Excessive expansion force can easily lead to safety risks in batteries, such as cracking of explosion-proof valves, cracking of aluminum shell welds, cracking of end plates, cracking of steel strips, etc.

[0003] At present, the most common way to detect expansion force is to install a pressure sensor outside the battery. However, there are many problems with pressure sensors, such as high detection costs due to the high price of pressure sensors and decreased detection accuracy due to drift of detection data as the pressure sensor is used. Summary of the invention

[0004] Based on the above problems, the present application provides a battery safety detection method, device, electronic device and storage medium, which can avoid many problems caused by the use of sensors, and can apply expansion force detection to battery modules and battery packs, thereby improving the safety of single cells, battery modules and battery packs.

[0005] In a first aspect, the present application provides a battery safety detection method, the method comprising: each time a triggering condition is detected, charging a target object using a preset charging process; wherein the preset charging process comprises a constant current charging stage and a constant voltage charging stage; the target object is one of a single cell, a battery module, and a battery pack; the triggering condition comprises at least one of the following: the target object is connected to a charging and discharging device; the target object is connected to the charging and discharging device within a preset time range; the number of charge and discharge cycles performed on the target object reaches a predicted number; the target object is detected according to a first charge amount in the constant current charging stage and a second charge amount in the constant voltage charging stage to obtain a safety detection result; the safety detection result is used to characterize whether the target object has an abnormal expansion force.

[0006] In the technical solution of the embodiment of the present application, by adopting a specific charging process and extracting charging amount data, it is possible to detect whether there is abnormal expansion force without using sensors and clamps. Therefore, many problems caused by using sensor detection can be avoided, and expansion force detection can be applied to battery modules and battery packs, thereby improving the safety of single cells, battery modules and battery packs.

[0007] In some embodiments, the first charge amount in the constant current charging stage and the second charge amount in the constant voltage charging stage are detected to obtain a safety detection result, including: calculating the ratio of the first charge amount obtained in this detection to the second charge amount; determining the safety detection result according to the ratio of this detection and the ratio of at least one historical detection. In the technical solution of the embodiment of the present application, the change of the charge amount in the constant voltage charging stage can be determined according to the ratio of this detection and the ratio of the historical detection, so as to accurately identify whether the target object has abnormal expansion force, reduce the risk of structural component fracture caused by abnormal expansion force, and thus improve the safety of single cells, battery modules and battery packs.

[0008] In some embodiments, determining the safety detection result based on the ratio of the current detection and the ratio of at least one historical detection includes: generating a curve of the ratio changing with the health status based on the ratio of the current detection and the ratio of multiple historical detections; and determining the safety detection result based on the position of the ratio of the current detection in the curve. The technical solution of the embodiment of the present application can intuitively and quickly determine the safety detection result through the curve of the ratio changing with the health status, thereby improving the detection efficiency.

[0009] In some embodiments, a preset charging process is used to charge the target object, including: discharging the target object until the voltage of the target object reaches a lower limit voltage; leaving the target object to rest for a first preset time; performing constant current charging on the target object until the voltage of the target object reaches an upper limit voltage; leaving the target object to rest for a second preset time; performing constant voltage charging on the target object until the charging current of the target object is lower than a preset current threshold. In the technical solution of the embodiment of the present application, constant current charging and constant voltage charging are performed on the target object, and safety detection results can be obtained by extracting charging amount data without using sensors and fixtures, which can not only save costs and avoid many problems caused by sensors, but also can apply detection to battery modules and battery packs, making safety detection more valuable.

[0010] In some embodiments, discharging the target object until the voltage of the target object reaches a lower voltage limit includes: discharging the target object with a first discharge current until the voltage of the target object reaches the lower voltage limit; leaving the target object to stand for a third preset time; discharging the target object with a second discharge current until the voltage of the target object reaches the lower voltage limit; wherein the second discharge current is less than the first discharge current. In the technical solution of the embodiment of the present application, completely discharging the target object can improve the accuracy of safety detection.

[0011] In some embodiments, the target object is subjected to charge-discharge cycle processing, including: discharging the target object until the voltage of the target object reaches a lower limit voltage; leaving the target object to stand for a fourth preset time; charging the target object with a constant current until the voltage of the target object reaches an upper limit voltage; and charging the target object with a constant voltage until the charging current of the target object is lower than a preset current threshold. In the technical solution of the embodiment of the present application, the target object is subjected to charge-discharge cycle processing, which can simulate the use status of a single cell, a battery module, and a battery pack, thereby obtaining the capacity ratio corresponding to different health states, and then obtaining accurate safety detection results.

[0012] In some embodiments, the method further includes: when the target object is a single battery cell, obtaining the expansion force data of the test battery cell in different health states; and verifying the safety detection result according to the expansion force data of the test battery cell in different health states. In the technical solution of the embodiment of the present application, the safety detection result can be verified according to the expansion force monitored in the experimental stage, thereby improving the accuracy of the safety detection result, prompting maintenance personnel to perform maintenance in a timely manner, and reducing various risks caused by abnormal expansion force.

[0013] In a second aspect, the present application also provides a battery safety detection device, the device comprising:

[0014] A charging module is used to charge a target object using a preset charging process each time a triggering condition is detected; wherein the preset charging process includes a constant current charging stage and a constant voltage charging stage; the target object is one of a single cell, a battery module, and a battery pack; the triggering condition includes at least one of the following: the target object is connected to a charging and discharging device; the target object is connected to the charging and discharging device within a preset time range; the number of charge and discharge cycles for the target object reaches a predicted number;

[0015] The detection module is used to detect the first charging amount in the constant current charging stage and the second charging amount in the constant voltage charging stage to obtain a safety detection result; the safety detection result is used to characterize whether the target object has an abnormal expansion force.

[0016] In a third aspect, the present application further provides an electronic device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements any one of the methods in the first aspect when executing the computer program.

[0017] In a fourth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the method of any one of the first aspects is implemented.

[0018] In a fifth aspect, the present application further provides a computer program product, comprising a computer program, which implements any one of the methods in the first aspect when executed by a processor. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the optional embodiments below. The accompanying drawings are only used for the purpose of illustrating the optional embodiments and are not to be considered as limiting the present application. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0020] Figure 1 A schematic diagram of an application environment of a battery safety detection method according to an embodiment of the present application;

[0021] Figure 2 It is a flowchart of a battery safety detection method according to an embodiment of the present application;

[0022] Figure 3 It is a flowchart of the steps of obtaining a safety detection result according to a first charging amount and a second charging amount in one embodiment of the present application;

[0023] Figure 4 It is a flowchart of a step of determining a safety detection result according to a ratio of a current detection and a ratio of at least one historical detection in an embodiment of the present application;

[0024] Figure 5 is a schematic diagram of a curve showing changes in ratio with health status according to an embodiment of the present application;

[0025] Figure 6 It is a flowchart of the steps of charging a target object using a preset charging process according to an embodiment of the present application;

[0026] Figure 7 is a schematic flow chart of the steps of discharging a target object according to an embodiment of the present application;

[0027] Figure 8 It is a schematic flow chart of the steps of performing a charge-discharge cycle treatment on a target object according to an embodiment of the present application;

[0028] Fig. 9 It is a flowchart of the steps of verifying the security detection results of an embodiment of the present application;

[0029] Fig.10 is a schematic diagram of an expansion force curve of an embodiment of the present application;

[0030] Fig.11 is a structural block diagram of a battery safety detection device according to an embodiment of the present application;

[0031] Fig.12 is a structural block diagram of a battery safety detection device according to an embodiment of the present application;

[0032] Fig.13 is a structural block diagram of a battery safety detection device according to an embodiment of the present application;

[0033] Fig.14 It is a diagram of the internal structure of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0034] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0036] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0037] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0038] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0039] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0040] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0041] With the development of new energy technology, lithium batteries are used in various fields, such as new energy vehicles, intelligent robots, etc. During use, lithium batteries will undergo multiple side reactions such as the growth of the SEI film at the solid electrolyte interface of the negative electrode, the loss of positive electrode materials, and the loss of negative electrode materials, resulting in irreversible loss of active lithium in lithium batteries, a decrease in life or capacity, and an increase in expansion force. Excessive expansion force can easily lead to safety risks in batteries, such as cracking of explosion-proof valves, cracking of aluminum shell welds, cracking of end plates, cracking of steel strips, etc. At present, the common way to detect expansion force is to set a pressure sensor outside the battery. However, there are many problems with pressure sensors, such as high prices and drift of detection data with use. In addition, for single cells, a three-piece steel fixture can be used to set a pressure sensor outside the single cell; for some special cells (such as cylindrical cells), and cells assembled in battery modules and battery packs (wrapped cylindrical cells, square shell cells, etc.), three-piece steel fixtures cannot be used. Therefore, it is impossible to monitor the expansion force changes and risks of cells in battery modules and battery packs.

[0042] Research on the above issues found that when abnormal lithium deposition occurs in the battery cell, the macroscopic manifestation of the battery cell is the increase and change of the expansion force, and the microscopic manifestation is that in addition to the lithium insertion impedance of graphite lithium insertion, the negative electrode also has the lithium deposition impedance of lithium deposition in parallel, and the total electrochemical impedance decreases. The reduction in the total electrochemical impedance will lead to a decrease in the charging polarization of the battery cell, that is, the proportion of the charge amount in the constant voltage charging stage in the total charge amount decreases. Since there is a certain correlation between lithium deposition and expansion force, and the change in charge amount in the constant voltage charging stage can reflect the lithium deposition situation, therefore, the change in charge amount in the constant voltage charging stage can also reflect the change in expansion force to a certain extent.

[0043] Based on the above findings, the embodiment of the present application provides a battery safety detection method, which uses a preset charging process to charge a single cell, a battery module or a battery pack each time a triggering condition is detected; then, detection is performed based on the first charge amount in the constant current charging stage and the second charge amount in the constant voltage charging stage to obtain a safety detection result. In the technical solution of the embodiment of the present application, a specific charging process is used and the charge amount data is extracted to detect whether there is an abnormal expansion force, without the need to use sensors and fixtures, so that many problems caused by the use of sensors can be avoided, and expansion force detection can be applied to battery modules and battery packs, thereby improving the safety of single cells, battery modules and battery packs.

[0044] The battery safety detection method provided in the embodiment of the present application can be applied to Figure 1 In the application environment shown. The application environment includes a target object 101 to be detected, an electronic device 102 and a charging and discharging device 103. Among them, the target object may include but is not limited to various single cells, battery modules and battery packs. Single cells, battery modules and battery packs can be test samples used in laboratories, products in production lines or market-end products. For example, battery packs are market-end products installed in new energy vehicles. Electronic device 102 can be a personal computer, a laptop computer, a smart phone, a tablet computer, etc. that is connected to the charging and discharging device 103 for communication. Electronic device 102 can also be a charging and discharging device including a controller. Charging and discharging device 103 can include but is not limited to charging and discharging machines used in laboratories and production lines and charging piles set up in the market. Electronic device 102 can charge and discharge single cells, battery modules and battery packs, and obtain relevant data during the charging and discharging process, and detect single cells, battery modules and battery packs according to the relevant data to determine whether there is abnormal expansion force in single cells, battery modules and battery packs.

[0045] According to some embodiments of the present application, referring to Figure 2 , provides a battery safety detection method, which is applied to Figure 1 Taking the electronic device in as an example, the method may include the following steps:

[0046] Step 201 : Each time a triggering condition is detected, a preset charging process is used to charge the target object.

[0047] The target object is one of a single battery cell, a battery module, and a battery pack. The triggering condition is a condition that triggers a safety detection. For example, when the electronic device detects that the user inputs a safety detection triggering operation, it determines that the target object is in a triggering condition.

[0048] The electronic device can detect the working condition of the target object in real time, and perform safety detection on the target object every time a triggering working condition is detected. During each safety detection process, the electronic device can send a preset charging process to the charging and discharging device; the charging and discharging device receives the preset charging process and charges the target object according to the preset charging process.

[0049] Alternatively, the electronic device generates multiple charging instructions and the execution time of each charging instruction according to a preset charging process; then, the multiple charging instructions and the execution time of each charging instruction are sent to the charging and discharging device. The charging and discharging device executes the multiple charging instructions in sequence according to the execution time to charge the target object.

[0050] Alternatively, the electronic device generates multiple charging instructions and execution time of each charging instruction according to a preset charging process; then, the charging instructions are sent to the charging and discharging device in sequence according to the execution time. Each time the charging and discharging device receives a charging instruction, it charges the target object according to the charging instruction.

[0051] It should be noted that the charging method is not limited to the above examples and can be set according to actual conditions in the application.

[0052] The above-mentioned preset charging process includes a constant current charging stage and a constant voltage charging stage, that is, when the charging and discharging device charges the target object, it usually performs constant current charging first and then constant voltage charging.

[0053] Step 202 , detecting the target object according to the first charging amount in the constant current charging stage and the second charging amount in the constant voltage charging stage to obtain a safety detection result.

[0054] Among them, the safety detection results are used to characterize whether the target object has abnormal expansion force.

[0055] When charging the target object, the charging and discharging device can record the first charge amount in the constant current charging stage and the second charge amount in the constant voltage charging stage. The electronic device can obtain the first charge amount and the second charge amount from the charging and discharging device, and then calculate the sum of the first charge amount and the second charge amount to obtain the total charge amount detected in this test, and then calculate the ratio between the second charge amount and the total charge amount to obtain the charge amount ratio in the constant voltage charging stage. The electronic device can determine the ratio threshold in advance based on the test data or historical data. If the charge amount ratio obtained in this test is greater than or equal to the ratio threshold, it indicates that the charge amount ratio in the constant voltage charging stage in this test has not been significantly reduced, and it is determined that the target object does not have an abnormal expansion force; if the charge amount ratio obtained in this test is less than the ratio threshold, it indicates that the charge amount ratio in the constant voltage charging stage in this test has been significantly reduced, and it is determined that the target object has an abnormal expansion force.

[0056] For example, in the nth detection, the first charge amount is Qan, the second charge amount is Qbn, the total charge amount is Qn=Qan+Qbn, and the proportion threshold is Q'. If Qn≥Q', it is determined that the target object does not have an abnormal expansion force; if Qn<Q', it is determined that the target object has an abnormal expansion force.

[0057] In some embodiments, when the target object is a battery module, the first charge capacity and the second charge capacity of the battery module can be determined according to the number of cells in the battery module. For example, the first charge capacity of the battery module is the sum of the first charge capacities of the multiple cells, and the second charge capacity of the battery module is the sum of the second charge capacities of the multiple cells.

[0058] Similarly, when the target object is a battery pack, the first charge capacity and the second charge capacity of the battery pack can be determined according to the number of cells in the battery pack. For example, the first charge capacity of the battery pack is the sum of the first charge capacities of the multiple cells, and the second charge capacity of the battery pack is the sum of the second charge capacities of the multiple cells.

[0059] In some embodiments, if the safety detection result indicates that the target object has an abnormal expansion force, a warning message is output, wherein outputting the warning message may include at least one of: outputting an alarm sound, lighting an alarm light, and displaying the alarm message on a display screen.

[0060] In some embodiments, the triggering condition includes at least one of the following: the target object is connected to the charging and discharging device; the target object is connected to the charging and discharging device within a preset time range; the number of charge and discharge cycle treatments on the target object reaches a predicted number.

[0061] In one of the scenarios, the target object is a battery pack installed in an electric vehicle, the charging and discharging device is a charging pile, and the electronic device is the controller of the charging pile. Each time the battery pack of the electric vehicle is connected to the charging gun of the charging pile, the controller determines that the battery pack is in a triggering condition and performs a safety test. The controller controls the charging pile to charge the battery pack according to a preset charging process, and then tests the battery pack according to the first charge amount in the constant current charging stage and the second charge amount in the constant voltage charging stage to determine whether the battery pack has abnormal expansion force.

[0062] In one of the scenarios, the target object is a battery pack installed in an electric vehicle, the charging and discharging device is a charging pile, and the electronic device is a controller of the charging pile. The battery pack of the electric vehicle is connected to the charging gun of the charging pile. If the controller detects that the connection time is within the preset time range, it determines that the battery pack is in a triggering condition and performs the above safety detection. For example, the preset time range can be X days of each month. It should be noted that the preset time range is not limited to the above examples and can be set according to actual conditions.

[0063] In one scenario, the target object is a battery pack installed in an electric vehicle, the charging and discharging device is a charging pile, and the electronic device is the controller of the charging pile. After the battery pack is connected to the charging gun, the controller detects that the battery pack has been charged and discharged for M times each time, and then determines that the battery pack is in a triggering condition, performs the above safety detection, and clears the number of charge and discharge cycles.

[0064] In one of the scenarios, the target object is a test sample such as a single cell or a battery module, the charging and discharging device is a charger and discharger, and the electronic device is a controller of the charger and discharger or a computer device connected to the charger and discharger. Each time the electronic device detects that the charger and discharger are connected to the test sample, or detects that the charger and discharger are connected to the test sample within a preset time range, it determines that the test sample is in a triggering condition and performs the above safety detection.

[0065] In one of the scenarios, the target object is a test sample such as a single cell or a battery module, the charging and discharging device is a charger and discharger, and the electronic device is a controller of the charger and discharger or a computer device connected to the charger and discharger. Every time the charger and discharger performs charge and discharge cycles on the test sample for M times, the electronic device determines that the battery pack is in a triggered condition, performs the above-mentioned safety test, and resets the number of charge and discharge cycles. For example, if the charger and discharger performs charge and discharge cycles on the test cell for 50 times, the controller controls the charger and discharger to charge the test cell according to the preset charging process, and performs a safety test on the test cell according to the charge amount; thereafter, the charger and discharger performs charge and discharge cycles on the test cell for another 50 times, and the controller performs the next safety test. And so on, multiple safety tests are performed.

[0066] It should be noted that the same target object may be in one or more of the above scenarios, and the conditions for triggering safety detection of the target object are not limited to the above examples and can be set according to actual conditions.

[0067] It can be understood that a variety of trigger conditions can trigger safety detection of the target object, making the safety detection scenario more comprehensive, thereby improving the safety of the target object.

[0068] In the above embodiment, each time a triggering condition is detected, a preset charging process is used to charge the target object; then, detection is performed based on the first charge amount in the constant current charging stage and the second charge amount in the constant voltage charging stage to obtain a safety detection result. In the technical solution of the embodiment of the present application, a specific charging process is used and the charge amount data is extracted to detect whether there is an abnormal expansion force, without the need to use sensors and fixtures, thereby avoiding many problems caused by the use of sensor detection, and expansion force detection can be applied to battery modules and battery packs, thereby improving the safety of single cells, battery modules and battery packs.

[0069] According to some embodiments of the present application, referring to Figure 3 In the above embodiment, “detecting according to the first charge amount in the constant current charging stage and the second charge amount in the constant voltage charging stage to obtain a safety detection result” may include the following steps:

[0070] Step 301, calculating the ratio of the first charge amount to the second charge amount obtained in this detection.

[0071] Since the ratio of the first charge amount to the second charge amount can also reflect the proportion of the charge amount in the constant voltage charging stage, the ratio between the first charge amount and the second charge amount can be directly calculated. For example, in the nth detection, the first charge amount is Qan, the second charge amount is Qbn, and the ratio of the first charge amount to the second charge amount is Qan / Qbn.

[0072] Step 302, determining a safety detection result according to a ratio of the current detection and a ratio of at least one historical detection.

[0073] The electronic device can store the ratio of the first charge amount to the second charge amount after each detection. After the current detection, the ratio of the current detection is compared with the ratio of the historical detection, and the safety detection result is determined according to the comparison result.

[0074] In some embodiments, the difference between the ratio of this detection and the ratio of historical detection is calculated. If the difference is greater than a preset difference, it indicates that the proportion of the charge amount in the constant voltage charging stage in this detection has decreased significantly, making the ratio of this detection much greater than the ratio of historical detection, and it can be determined that the target object has an abnormal expansion force. If the difference is less than the preset difference, it indicates that the proportion of the charge amount in the constant voltage charging stage in this detection has decreased slightly, and the ratio of this detection is close to the ratio of historical detection, and it can be determined that the target object does not have an abnormal expansion force.

[0075] In some embodiments, a prediction is made based on the ratio of the current detection and at least one ratio of a historical detection to obtain a ratio of a future detection; a curve fitting is performed based on the ratio of the current detection, the ratio of the historical detection, and the ratio of the future detection, and the safety detection result is determined based on the change trend of the first curve obtained by fitting. For example, if the ratio of the current detection is at the inflection point of the first curve, it can be determined that the target object has an abnormal expansion force; if the ratio of the current detection is not at the inflection point of the first curve, it can be determined that the target object does not have an abnormal expansion force.

[0076] In some embodiments, a curve fitting is performed based on at least one ratio of historical detection, and a safety detection result is determined based on the relationship between the second curve obtained by fitting and the ratio of this detection. For example, if the ratio of this detection is not on the second curve or the distance between the ratio and the second curve exceeds a preset distance range, it can be determined that the target object has an abnormal expansion force; if the ratio of this detection is on the second curve or the distance between the ratio and the second curve is within a preset distance range, it can be determined whether the target object has an abnormal expansion force.

[0077] It should be noted that the method for determining the safety detection result is not limited to the above example, and a more appropriate determination method can be adopted according to actual conditions.

[0078] In the above embodiment, the ratio of the first charge amount to the second charge amount obtained in this detection is calculated; and the safety detection result is determined based on the ratio of this detection and the ratio of at least one historical detection. In the technical solution of the embodiment of the present application, the change of the charge amount in the constant voltage charging stage can be determined based on the ratio of this detection and the ratio of the historical detection, so as to accurately identify whether the target object has abnormal expansion force, reduce the risk of structural parts fracture caused by abnormal expansion force, and thus improve the safety of single cells, battery modules and battery packs.

[0079] According to some embodiments of the present application, referring to Figure 4 In the above embodiment, “determining the safety detection result according to the ratio of the current detection and the ratio of at least one historical detection” may include the following steps:

[0080] Step 3021, based on the ratio of this test and the ratios of multiple historical tests, generate a curve showing the ratio changing with the health status.

[0081] Among them, the state of health (SOH) characterizes the ability of the battery to store electrical energy in the current state relative to the initial state. It expresses the state of the battery from the beginning to the end of its life in the form of a percentage, and is used to quantitatively describe the current performance state of the battery. Among them, the initial state can be the state after formation and full charge.

[0082] When the target object is in the initial state, the target object is first charged according to the preset charging process to obtain the first charge amount in the constant current charging stage and the second charge amount in the constant voltage charging stage, and the sum of the first charge amount and the second charge amount is calculated to obtain the rated capacity of the target object. Subsequently, in each test, the sum of the first charge amount and the second charge amount is calculated to obtain the total charge amount corresponding to the test; then, the health status is calculated based on the total charge amount and the rated capacity corresponding to the test.

[0083] For example, in the first detection, the first charge amount Qa1 in the constant current charging stage and the second charge amount Qb1 in the constant voltage charging stage are obtained, and the rated capacity Q1=Qa1+Qb1. In the nth detection, the first charge amount Qan in the constant current charging stage and the second charge amount Qbn in the constant voltage charging stage are obtained, and the total capacity detected in the nth detection is Qn=Qan+Qbn, the ratio of the nth detection is Qan / Qbn, and the health status corresponding to the nth detection is Qn / Q1.

[0084] After calculating the ratio of this test and the health status corresponding to this test, a curve showing the ratio changing with the health status can be generated based on the ratio and health status of historical tests. Figure 5 As shown, the horizontal axis is the health status and the vertical axis is the ratio. It can be seen from the figure that with use, the health status of the target object gradually decreases from 100%, while the ratio gradually increases with the decrease in the health status, and after the health status drops to 80%, the ratio increases sharply.

[0085] Step 3022, determine the safety detection result according to the position of the ratio of this detection in the curve.

[0086] Reference Figure 5 If the ratio of this test is between 75% and 100% of the healthy state on the curve, it can be determined that the safety test result indicates that the target object has no abnormal expansion force; if the ratio of this test is between 70% and 75% of the healthy state on the curve, it can be determined that the safety test result indicates that the target object has abnormal expansion force.

[0087] It should be noted that the healthy state in the figure is between 75% and 80%. The curve has not shown an inflection point, but has shown a trend of sharp increase. Therefore, when the ratio of this test is in this range, it is determined that the target object has abnormal expansion force, which can serve as an early warning, thereby ensuring the safety of the battery.

[0088] In the above embodiment, a curve showing the ratio changing with the health status is generated based on the ratio of the current detection and the ratio of multiple historical detections; and the safety detection result is determined based on the position of the ratio of the current detection in the curve. The technical solution of the embodiment of the present application can intuitively and quickly determine the safety detection result through the curve showing the ratio changing with the health status, thereby improving the detection efficiency.

[0089] According to some embodiments of the present application, referring to Figure 6 In the above embodiment, “charging the target object using a preset charging process” may include the following steps:

[0090] Step 401 : discharging a target object until the voltage of the target object reaches a lower limit voltage.

[0091] When the target object is a single cell, the single cell is discharged to a lower limit voltage of 2.0V.

[0092] When the target object is a battery module, the lower limit voltage of the battery module is determined according to the number and connection relationship of the battery cells in the battery module. For example, if the battery module is composed of N battery cells connected in series and the lower limit voltage of each battery cell is 2.0V, then the lower limit voltage of the battery module is 2.0V*N.

[0093] Similarly, when the target object is a battery pack, the lower limit voltage of the battery pack is determined according to the number and connection relationship of the battery cells in the battery module.

[0094] The electronic device discharges the target battery until the voltage of the target object reaches the lower limit voltage. For example, the charging and discharging method of the battery module is as follows: N cells are connected in series, sharing a positive and negative output electrode, and the battery module is charged and discharged through the total output electrode, and the positive and negative electrodes of each cell are connected respectively using an auxiliary channel to monitor the voltage value of each single cell.

[0095] In some embodiments, the target object may be left to stand for 5 to 10 minutes before discharge, so that the target object can reach a balanced state before discharge.

[0096] Step 402: Leave the target object still for a first preset time period.

[0097] Let the target object stand for 5-10 minutes. The purpose of standing still is to allow the target object to return to a balanced state after discharge.

[0098] Step 403 , performing constant current charging on the target object until the voltage of the target object reaches an upper limit voltage.

[0099] With reference to the above embodiments, the upper limit voltage of a single cell, a battery module and a battery pack may be determined.

[0100] The target object is charged with a constant current using a charging current of 0.1~0.33C until the voltage of the target object reaches 3.65V or 3.65V*N.

[0101] Step 404: Leave the target object still for a second preset time period.

[0102] Let the target object stand for 10 to 30 minutes. The purpose of standing still is to allow the target object to return to a balanced state after charging.

[0103] Step 405 , performing constant voltage charging on the target object until the charging current of the target object is lower than a preset current threshold.

[0104] The target object is charged at a constant voltage of 3.65V or 3.65V*N until the charging current of the target object is lower than 0.04C. Alternatively, the charging current of the target object is between 0.01 and 0.04C.

[0105] It should be noted that the lower voltage limit, the upper voltage limit, the preset current threshold, the first preset time length and the second preset time length are not limited to the above examples, and in practical applications, they can be set according to the actual situation.

[0106] In the above embodiment, the target object is discharged until the voltage of the target object reaches the lower limit voltage; the target object is left to stand for a first preset time; the target object is charged with constant current until the voltage of the target object reaches the upper limit voltage; the target object is left to stand for a second preset time; the target object is charged with constant voltage until the charging current of the target object is lower than the preset current threshold. In the technical scheme of the embodiment of the present application, the target object is charged with constant current and constant voltage, and the safety detection result can be obtained by extracting the charging amount data without using sensors and fixtures, which can not only save costs and avoid many problems caused by sensors, but also can apply the detection to battery modules and battery packs, making the safety detection more valuable.

[0107] According to some embodiments of the present application, referring to Figure 7 In the above embodiment, “discharging the target object until the voltage of the target object reaches the lower limit voltage” may include the following steps:

[0108] Step 4011: Discharge the target object with a first discharge current until the voltage of the target object reaches a lower limit voltage.

[0109] Due to the existence of ohmic impedance, electrochemical impedance, etc. inside the battery cell, there is a certain polarization effect during discharge, which causes the battery cell to be unable to discharge completely. In order to ensure the accuracy of safety detection, the target object needs to be completely discharged.

[0110] The target object can be discharged at 0.1~0.33C until the voltage of the target object reaches 2.0V or 2.0V*N.

[0111] In some embodiments, the target object may be left to stand for 5 to 10 minutes before discharge, so that the target object can reach a balanced state before discharge.

[0112] Step 4012: Leave the target object still for a third preset time period.

[0113] The target object is left to stand for 10 to 30 minutes. The purpose of standing is to allow the target object to return to a balanced state after discharge. It should be noted that the third preset time length may be the same as the second preset time length, or may be different from the second preset time length.

[0114] Step 4013: Discharge the target object with a second discharge current until the voltage of the target object reaches a lower limit voltage.

[0115] After the target object is left to stand, the voltage may rise. Therefore, the target object can be discharged again at 0.01~0.04C until the voltage of the target object reaches 2.0V or 2.0V*N. In addition, the second discharge current is smaller than the first discharge current, which can reduce the discharge speed and make the target object discharge more completely.

[0116] In the above embodiment, the target object is discharged with a first discharge current until the voltage of the target object reaches a lower limit voltage; the target object is left to stand for a third preset time; the target object is discharged with a second discharge current until the voltage of the target object reaches a lower limit voltage. In the technical solution of the embodiment of the present application, the target object is completely discharged, which can improve the accuracy of safety detection.

[0117] According to some embodiments of the present application, referring to Figure 8 In the above embodiment, “performing a charge-discharge cycle process on the target object” includes:

[0118] Step 501 : discharging a target object until the voltage of the target object reaches a lower limit voltage.

[0119] The target object is discharged with a discharge current of 1C until the voltage of the target object reaches 2.0V or 2.0V*N.

[0120] Step 502: Leave the target object still for a fourth preset time period.

[0121] Let the target object stand for 10 minutes. The purpose of standing still is to allow the target object to return to a balanced state after discharge.

[0122] Step 503 , performing constant current charging on the target object until the voltage of the target object reaches an upper limit voltage.

[0123] The target object is charged with a constant current using a charging current of 1C until the voltage of the target object reaches 3.65V or 3.65V*N.

[0124] Step 504 , performing constant voltage charging on the target object until the charging current of the target object is lower than a preset current threshold.

[0125] The target object is charged at a constant voltage using a charging voltage of 3.65V or 3.65V*N until the current of the target object is lower than 0.05C.

[0126] It should be noted that the discharge current, the charging current, the charging voltage, the lower limit voltage, the upper limit voltage, and the preset current threshold are not limited to the above examples, and in application, they can be set according to actual conditions.

[0127] In the above embodiment, the target object is discharged until the voltage of the target object reaches the lower limit voltage; the target object is left to stand for a fourth preset time; the target object is charged with a constant current until the voltage of the target object reaches the upper limit voltage; the target object is charged with a constant voltage until the charging current of the target object is lower than the preset current threshold. In the technical solution of the embodiment of the present application, the target object is subjected to charge and discharge cycle processing, which can simulate the use status of a single cell, a battery module, and a battery pack, so as to obtain the capacity ratio corresponding to different health states, and then obtain accurate safety detection results.

[0128] According to some embodiments of the present application, referring to Fig. 9 , and may also include the following steps:

[0129] Step 601, when the target object is a single battery cell, obtain expansion force data of the test battery cell in different health states.

[0130] When the target object is a single cell, a pressure sensor can be set outside the test cell through a three-piece steel fixture. During the safety inspection of the test cell, the expansion force data of the test cell is monitored through the pressure sensor. The initial pressure of the fixture can be 800~1000kgf.

[0131] According to the first charge amount in the constant current charging stage and the second charge amount in the constant voltage charging stage, the ratio of the first charge amount to the second charge amount, the health state of the test cell, and the curve of the ratio of the first charge amount to the second charge amount versus the health state can be determined. Figure 5 .

[0132] According to the health status of the tested battery cell and the monitored expansion force data, the expansion force data under different health status can be determined and an expansion force curve can be generated. Fig.10 In the figure, the horizontal axis is the health state and the vertical axis is the expansion force. It can be seen from the figure that with use, the health state gradually decreases from 100%, the expansion force increases with the decrease of the health state, and after the health state is lower than 80%, the expansion force increases sharply.

[0133] Step 602 , verifying the safety test result according to the expansion force data of the test cell in different health states.

[0134] Reference Fig.10 The expansion force data of the battery cells in different health states can be used to Figure 5It can be verified by comparing the changes of the ratio with the health status. As can be seen from the two figures, when the health status is lower than 80%, the expansion force increases sharply, but the ratio does not change significantly. When the health status is lower than 75%, the ratio increases sharply. In other words, the expansion force abnormality determined by the ratio may lag behind the actual monitored expansion force abnormality.

[0135] Based on the above findings, in practical applications, the safety test results can be corrected in combination with the health status. For example, the safety test result is determined based on the ratio to indicate that the battery pack does not have abnormal expansion force. Combined with the health status of the battery pack, the safety test result is corrected to indicate that the battery pack has abnormal expansion force, so as to prompt maintenance personnel to maintain the battery pack.

[0136] Alternatively, the safety test results are combined with the health status to output corresponding warning information. For example, according to the ratio, the safety test results indicate that there is no abnormal expansion force in the battery pack. If the health status of the battery pack is between 80% and 100%, a low-risk warning is output; if the health status of the battery pack is between 70% and 80%, a medium-risk warning is output; if the health status of the battery pack is less than 70%, a high-risk warning is output.

[0137] It should be noted that the method of verifying the safety detection results based on the expansion force data monitored by the sensor is not limited to the above example and can be set according to actual conditions.

[0138] In the above embodiment, when the target object is a single battery cell, the expansion force data of the test battery cell in different health states are obtained; and the safety detection result is verified according to the expansion force data of the test battery cell in different health states. In the technical solution of the embodiment of the present application, the safety detection result can be verified according to the expansion force monitored in the experimental stage, thereby improving the accuracy of the safety detection result, prompting maintenance personnel to perform maintenance in time, and reducing various risks caused by abnormal expansion force.

[0139] According to some embodiments of the present application, a battery safety detection method is provided. Figure 1 Taking the electronic device in the example as an example, the following steps may be included:

[0140] Step 1: Discharge the target object with a first discharge current until the voltage of the target object reaches a lower limit voltage each time it is detected that the target object is connected to the charge and discharge device, or the target object is connected to the charge and discharge device within a preset time range, or the number of charge and discharge cycles on the target object reaches a predicted number.

[0141] Step 2: Leave the target object still for a third preset time period.

[0142] Step 3: Discharging the target object with a second discharge current until the voltage of the target object reaches a lower limit voltage; wherein the second discharge current is smaller than the first discharge current.

[0143] Step 4: Leave the target object still for a first preset time period.

[0144] Step 5: Perform constant current charging on the target object until the voltage of the target object reaches an upper limit voltage.

[0145] Step 6: Leave the target object still for a second preset time period.

[0146] Step 7: Perform constant voltage charging on the target object until the charging current of the target object is lower than a preset current threshold.

[0147] Step 8, calculating the ratio of the first charge amount to the second charge amount obtained in this detection.

[0148] Step 9, generating a curve showing the ratio changing with the health status based on the ratio of the current test and the ratios of multiple historical tests.

[0149] Step 10, determining a safety detection result according to the position of the ratio of this detection in the curve, wherein the safety detection result indicates whether the target object has an abnormal expansion force.

[0150] In the above embodiments, safety detection is performed under different triggering conditions, which can make the safety detection scenario more comprehensive. In addition, the target object is fully discharged before the safety detection, which can improve the accuracy of the safety detection. Furthermore, safety detection can be achieved by charging according to the preset charging process and extracting the charging amount data, without setting up sensors and fixtures, which can not only save costs and avoid many problems caused by the use of sensors, but also apply safety detection to battery modules and battery packs, thereby improving the safety of single cells, battery modules and battery packs, and improving the application value of safety detection.

[0151] It should be understood that, although the various steps in the above flowchart are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear description in this article, the execution of these steps is not strictly limited in order, and these steps can be executed in other orders. Moreover, at least a part of the steps in the above flowchart may include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0152] Based on the same inventive concept, the embodiment of the present application also provides a battery safety detection device for implementing the battery safety detection method involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more battery safety detection device embodiments provided below can refer to the limitations of the battery safety detection method above, and will not be repeated here.

[0153] According to some embodiments of the present application, referring to Fig.11 , provides a battery safety detection device, the device comprising:

[0154] The charging module 701 is used to charge the target object using a preset charging process each time a triggering condition is detected; wherein the preset charging process includes a constant current charging stage and a constant voltage charging stage; the target object is one of a single cell, a battery module, and a battery pack; the triggering condition includes at least one of the following: the target object is connected to the charging and discharging device; the target object is connected to the charging and discharging device within a preset time range; the number of charge and discharge cycles for the target object reaches the predicted number;

[0155] The detection module 702 is used to detect the target object according to the first charging amount in the constant current charging stage and the second charging amount in the constant voltage charging stage to obtain a safety detection result; the safety detection result is used to characterize whether the target object has an abnormal expansion force.

[0156] In some embodiments, the detection module 702 is specifically used to calculate the ratio of the first charge amount to the second charge amount obtained in this detection; and determine the safety detection result according to the ratio of this detection and the ratio of at least one historical detection.

[0157] In some embodiments, the detection module 702 is specifically used to generate a curve showing changes in ratio with health status based on the ratio of the current detection and the ratios of multiple historical detections; and determine the safety detection result based on the position of the ratio of the current detection in the curve.

[0158] In some embodiments, the charging module 701 is specifically used to discharge the target object until the voltage of the target object reaches a lower limit voltage; keep the target object still for a first preset time; perform constant current charging on the target object until the voltage of the target object reaches an upper limit voltage; keep the target object still for a second preset time; perform constant voltage charging on the target object until the charging current of the target object is lower than a preset current threshold.

[0159] In some embodiments, the charging module 701 is specifically used to discharge the target object with a first discharge current until the voltage of the target object reaches a lower limit voltage; leave the target object stationary for a third preset time; and discharge the target object with a second discharge current until the voltage of the target object reaches a lower limit voltage; wherein the second discharge current is less than the first discharge current.

[0160] In some embodiments, reference Fig.12 , the device further comprises:

[0161] The cycle module 703 is used to discharge the target object until the voltage of the target object reaches a lower limit voltage; let the target object stand for a fourth preset time; perform constant current charging on the target object until the voltage of the target object reaches an upper limit voltage; and perform constant voltage charging on the target object until the charging current of the target object is lower than a preset current threshold.

[0162] In some embodiments, reference Fig.13 , the device further comprises:

[0163] The expansion force acquisition module 704 is used to acquire the expansion force data of the test cell under different health states when the target object is a single cell;

[0164] The verification module 705 is used to verify the safety test result according to the expansion force data of the test cell under different health conditions.

[0165] Each module in the above battery safety detection device can be implemented in whole or in part by software, hardware, or a combination thereof. Each module can be embedded in or independent of a processor in an electronic device in the form of hardware, or can be stored in a memory in the electronic device in the form of software, so that the processor can call and execute the operations corresponding to each module.

[0166] According to some embodiments of the present application, an electronic device is provided. The electronic device may be a terminal, and its internal structure diagram may be as follows: Fig.14As shown. The electronic device includes a processor, a memory, an input / output interface, a communication interface, a display unit and an input device. The processor, the memory and the input / output interface are connected through a system bus, and the communication interface, the display unit and the input device are connected to the system bus through the input / output interface. The processor of the electronic device is used to provide computing and control capabilities. The memory of the electronic device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The input / output interface of the electronic device is used to exchange information between the processor and an external device. The communication interface of the electronic device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be implemented through WIFI, a mobile cellular network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a battery safety detection method is implemented. The display unit of the electronic device is used to form a visually visible picture, which can be a display screen, a projection device or a virtual reality imaging device. The display screen can be a liquid crystal display screen or an electronic ink display screen, and the input device of the electronic device can be a touch layer covering the display screen, or a button, trackball or touchpad set on the electronic device casing, or an external keyboard, touchpad or mouse.

[0167] Those skilled in the art will understand that Fig.14 The structure shown in the figure is merely a block diagram of a partial structure related to the scheme of the present application, and does not constitute a limitation on the electronic device to which the scheme of the present application is applied. The specific electronic device may include more or fewer components than shown in the figure, or combine certain components, or have a different arrangement of components.

[0168] According to some embodiments of the present application, there is also provided a non-transitory computer-readable storage medium including instructions, such as a memory including instructions, and the above instructions can be executed by a processor of an electronic device to complete the above method. For example, the non-transitory computer-readable storage medium can be a ROM, a random access memory (RAM), a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, etc.

[0169] According to some embodiments of the present application, a computer program product is also provided, and when the computer program is executed by a processor, the above method can be implemented. The computer program product includes one or more computer instructions. When these computer instructions are loaded and executed on a computer, part or all of the above method can be implemented in whole or in part according to the process or function described in the embodiment of the present application.

[0170] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited to this.

[0171] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0172] The above-described embodiments only express several implementation methods of the present application, which is convenient for understanding the technical solutions of the present application in detail, but cannot be understood as limiting the scope of protection of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, several modifications and improvements can be made, which all belong to the protection scope of the present application. It should be understood that the technical solutions obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the technical solutions provided in the present application are all within the protection scope of the attached claims described in the present application. Therefore, the protection scope of the patent of this application shall be based on the contents of the attached claims, and the description and drawings can be used to explain the contents of the claims.

Claims

1. A battery safety detection method, characterized in that: The method comprises: Each time a triggering condition is detected, a preset charging process is used to charge the target object; wherein the preset charging process includes a constant current charging stage and a constant voltage charging stage; the target object is one of a single cell, a battery module, and a battery pack, and the target object includes at least one of a test sample used in a laboratory, a product in a production line, and a market-end product; the triggering condition includes at least one of the following: the target object is connected to a charging and discharging device; the target object is connected to the charging and discharging device within a preset time range; the number of charge and discharge cycles for the target object reaches the predicted number; The target object is detected according to the first charge amount in the constant current charging stage and the second charge amount in the constant voltage charging stage to obtain a safety detection result; the safety detection result is used to characterize whether the target object has an abnormal expansion force; Wherein, the expansion force is associated with lithium deposition, and lithium deposition leads to a decrease in the total electrochemical impedance and a decrease in the proportion of the charge amount in the constant voltage charging stage in the total charge amount; the detection is performed according to the first charge amount in the constant current charging stage and the second charge amount in the constant voltage charging stage to obtain a safety detection result, including: Calculating a ratio of the first charge amount to the second charge amount obtained in this detection; The safety detection result is determined according to a ratio of the current detection and a ratio of at least one historical detection.

2. The method according to claim 1, characterized in that: Determining the safety detection result according to the ratio of the current detection and the ratio of at least one historical detection includes: Generate a curve showing changes in the ratio with health status according to the ratio of the current test and the ratios of the plurality of historical tests; The safety detection result is determined according to the position of the ratio of the current detection in the curve.

3. The method according to claim 1, characterized in that The charging process of the target object using a preset charging process includes: discharging the target object until the voltage of the target object reaches a lower limit voltage; Allowing the target object to remain stationary for a first preset time period; Performing constant current charging on the target object until the voltage of the target object reaches an upper limit voltage; leaving the target object still for a second preset time period; The target object is charged at a constant voltage until a charging current of the target object is lower than a preset current threshold.

4. The method according to claim 3, characterized in that The step of discharging the target object until the voltage of the target object reaches a lower limit voltage includes: discharging the target object with a first discharge current until the voltage of the target object reaches the lower limit voltage; leaving the target object still for a third preset time period; The target object is discharged using a second discharge current until the voltage of the target object reaches the lower limit voltage; wherein the second discharge current is less than the first discharge current.

5. The method according to claim 1, characterized in that: The charging and discharging cycle treatment of the target object includes: discharging the target object until the voltage of the target object reaches a lower limit voltage; leaving the target object still for a fourth preset time period; Performing constant current charging on the target object until the voltage of the target object reaches an upper limit voltage; The target object is charged at a constant voltage until a charging current of the target object is lower than a preset current threshold.

6. The method according to any one of claims 1 to 5, characterized in that: The method further comprises: When the target object is a single battery cell, obtaining expansion force data of the test battery cell in different health states; The safety test result is verified according to the expansion force data of the test battery cell in different health states.

7. A battery safety detection device, characterized in that: The device comprises: A charging module is used to charge a target object using a preset charging process each time a triggering condition is detected; wherein the preset charging process includes a constant current charging stage and a constant voltage charging stage; the target object is one of a single cell, a battery module, and a battery pack, and the target object includes at least one of a test sample used in a laboratory, a product in a production line, and a market-end product; the triggering condition includes at least one of the following: the target object is connected to a charging and discharging device; the target object is connected to the charging and discharging device within a preset time range; the number of charge and discharge cycles for the target object reaches a predicted number; A detection module, used for performing detection according to the first charge amount in the constant current charging stage and the second charge amount in the constant voltage charging stage to obtain a safety detection result; the safety detection result is used to characterize whether the expansion force of the target object is abnormal; Among them, the expansion force is correlated with lithium deposition, and lithium deposition leads to a decrease in the total electrochemical impedance and a decrease in the proportion of the charge amount in the constant voltage charging stage in the total charge amount; the detection module is specifically used to calculate the ratio of the first charge amount to the second charge amount obtained in this detection; and determine the safety detection result based on the ratio of this detection and the ratio of at least one historical detection.

8. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the method according to any one of claims 1 to 6 is implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 6 is implemented.

Images