Detection method and detection apparatus for battery apparatus

Abstract

Embodiments of the present application provide a detection method and detection apparatus for a battery apparatus. The battery apparatus comprises a plurality of battery cells. The detection method comprises: acquiring information about current and time of a plurality of battery cells in a target phase, the target phase comprising a phase in which current decreases during target constant-voltage charging after charging to a charging cut-off voltage; determining, on the basis of the information about the current and time of the plurality of battery cells in the target phase, a plurality of slope values corresponding to current-time function relationships of the plurality of battery cells in the target phase; and detecting a battery apparatus on the basis of the plurality of slope values respectively corresponding to the plurality of battery cells in the target phase. The detection method and detection apparatus for a battery apparatus provided in the present application can accurately detect battery apparatuses.

Description

Testing methods and testing devices for battery devices Cross-reference to related applications

[0001] This application claims priority to Chinese Patent Application No. 202510192221.1, filed on February 20, 2025, entitled “Detection Method and Detection Apparatus for Battery Device”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of battery testing technology, and more specifically, to a testing method and testing device for a battery device. Background Technology

[0003] During battery use, it is necessary to test the battery to determine whether it meets the user's needs. For example, during use, external forces or other factors may cause structural failures in the battery, such as damage to parts of the battery cell, like welds, leading to electrolyte leakage and affecting battery performance and lifespan.

[0004] Therefore, how to accurately test batteries during their use is one of the urgent problems to be solved. Summary of the Invention

[0005] This application provides a method and apparatus for detecting battery devices, which can improve the accuracy of battery device detection.

[0006] Firstly, a method for detecting a battery device is provided. The battery device includes multiple battery cells. The detection method includes: acquiring current and time information of the multiple battery cells in a target stage, the target stage including the current decrease stage during the target constant voltage charging process after charging to the charging cutoff voltage; determining multiple slope values ​​corresponding to the current-time function relationship of the multiple battery cells in the target stage based on the current and time information of the multiple batteries in the target stage; and detecting the battery device based on the multiple slope values ​​corresponding to the multiple battery cells respectively.

[0007] In this embodiment, based on the current and time information of multiple battery cells during the current-time decrease phase of the target charging process, multiple slope values ​​corresponding to the current-time function relationship of each battery cell in the target phase can be determined. The state of the multiple battery cells can then be determined based on these slope values, thereby enabling the detection of the battery device. This improves the accuracy of battery device detection and simplifies the operation of battery device detection by allowing detection during the charging process.

[0008] In one possible implementation, based on the current and time information of multiple batteries during the target stage, multiple slope values ​​corresponding to the current-time function relationship of multiple battery cells during the target stage are determined, including: using the current of multiple battery cells during the target stage as the ordinate, and... Using the x-axis as the horizontal axis, target lines for multiple battery cells are obtained, and multiple slope values ​​corresponding to the target lines of multiple battery cells are determined, where t is the time of multiple battery cells in the target stage.

[0009] In this embodiment, multiple slope values ​​corresponding to the target lines of multiple battery cells can be determined based on the current and time information of the current decrease phase during the target charging process. The state of the multiple battery cells can then be determined based on these slope values, thereby enabling the detection of the battery device. This improves the accuracy of battery device detection and simplifies the operation of battery device detection by allowing detection during the charging process.

[0010] In one possible implementation, multiple battery cells are connected in series, and before acquiring information on the current and time of the multiple battery cells at a target stage, the method includes: performing constant voltage charging on the multiple battery cells, the constant voltage charging including the target constant voltage charging.

[0011] In this embodiment of the application, the target constant voltage charging of multiple battery cells can be achieved by performing constant voltage charging on multiple battery cells, thereby obtaining information on the current and time of multiple battery cells at the target stage.

[0012] In one possible implementation, constant voltage charging of multiple battery cells includes: controlling a first charging device to individually charge the multiple battery cells at a constant voltage, the first charging device being connected to the charging ports of the multiple battery cells.

[0013] In this embodiment of the application, by controlling the first charging device to charge multiple battery cells individually, it is convenient to independently control the charging of multiple battery cells, which can reduce the possibility of overcharging multiple battery cells, thereby improving the performance and service life of the battery device.

[0014] In one possible implementation, before controlling the first charging device to individually charge multiple battery cells at constant voltage, the detection method further includes: controlling the second charging device to charge the entire battery device, the second charging device being connected to the charging port of the battery device; and controlling the second charging device to stop charging the battery device when any battery cell in the battery device reaches the charging cutoff voltage.

[0015] In this embodiment of the application, when a battery cell in the battery device reaches the charging cutoff voltage, controlling the second charging device to stop charging the battery device can reduce the risk of overcharging of that battery cell, thereby reducing the impact on the performance and lifespan of the battery device.

[0016] In one possible implementation, controlling the second charging device to charge the battery device as a whole includes: controlling the second charging device to perform constant current charging on the battery device.

[0017] In this embodiment of the application, the battery device is charged at a constant current by a second charging device until a single battery cell reaches the charging cutoff voltage, which can improve the charging efficiency of the battery device, reduce the charging time, and thus reduce the time required to detect the battery device.

[0018] On the other hand, multiple battery cells are connected in series and the entire battery device is charged with constant current through a second charging device. The charging current of multiple battery cells is consistent, which facilitates the control of constant current charging among multiple battery cells.

[0019] In one possible implementation, constant voltage charging of multiple individual battery cells includes: controlling a third charging device to perform constant voltage charging on the entire battery device, wherein the third charging device is connected to the charging port of the battery device.

[0020] In this embodiment, by controlling a third charging device to perform constant voltage charging on the entire battery device, it can be applied to the scenario where current charging piles charge battery devices such as battery packs. This eliminates the need to modify the charging port of the charging pile, reducing the modification cost for battery device testing.

[0021] In one possible implementation, before controlling the third charging device to perform constant voltage charging on the entire battery device, the detection method further includes: controlling the third charging device to charge the entire battery device until the voltage of the battery device is less than (Vmax1+Vmax2+……VmaxN) and greater than or equal to (Vmax1+Vmax2+……VmaxN-0.5*N), where Vmax1, Vmax2, …, VmaxN are the charging cutoff voltages of multiple battery cells, and N is the number of multiple battery cells.

[0022] In this embodiment of the application, by controlling the third charging device as a whole to charge the battery device to a voltage between (Vmax1+Vmax2+……VmaxN-0.5*N) and (Vmax1+Vmax2+……VmaxN), the possibility of overcharging individual battery cells in the battery device can be reduced, thereby reducing the impact of overcharging individual battery cells on the performance and lifespan of the battery device.

[0023] In one possible implementation, before controlling the third charging device to charge the entire battery device, the detection method further includes: controlling the third charging device to charge the entire battery device, so that the voltage of the battery device is charged to a value range of (Vmax*N-0.3*N)~(Vmax*N-0.1*N), where Vmax is the charging cutoff voltage of one of the multiple battery cells.

[0024] In this embodiment of the application, by controlling the third charging device to charge the battery device to a voltage between (Vmax*N-0.3*N) and (Vmax*N-0.1*N), the possibility of overcharging individual battery cells in the battery device can be reduced, thereby reducing the impact of overcharging individual battery cells on the performance and lifespan of the battery device.

[0025] In one possible implementation, controlling the third charging device to charge the battery device as a whole includes: controlling the third charging device to perform constant current charging on the battery device.

[0026] In this embodiment of the application, the battery device is charged at a constant current by a third charging device until a single battery cell reaches the charging cutoff voltage, which can improve the charging efficiency of the battery device, reduce the charging time, and thus reduce the time required to detect the battery device.

[0027] In one possible implementation, information on the current and time of multiple battery cells in a target phase is obtained, including: obtaining information on the current and time of each battery cell in multiple target phases, wherein the multiple target phases are the phases during which the current decreases during multiple target constant voltage charging processes after multiple charging to the charging cutoff voltage.

[0028] In this embodiment of the application, by acquiring the current and time information of each battery cell in multiple target stages, it is convenient to determine the multiple slope values ​​corresponding to each battery cell in multiple target stages. Then, based on the changing trend of the multiple slope values ​​corresponding to each battery cell, it is possible to accurately determine whether the battery device has experienced structural failure without disassembling the battery device, thus facilitating the detection of structural failure of the battery device.

[0029] In one possible implementation, the current of multiple battery cells at the target stage is used as the vertical axis, and the current of multiple battery cells at the target stage is used as the horizontal axis. Using the x-axis as the horizontal axis, target lines for multiple battery cells are obtained, and multiple slope values ​​corresponding to the target lines of multiple battery cells are determined, including: using the current of each battery cell in multiple target stages as the vertical axis, and using... Using the x-axis as the horizontal axis, we obtain multiple target lines for each of the multiple battery cells, and determine multiple slope values ​​corresponding to the multiple target lines for each of the multiple battery cells.

[0030] In this embodiment of the application, by determining multiple slope values ​​of multiple target lines corresponding to multiple battery cells at multiple target stages, the structural failure of the battery device can be determined by the changing trend of multiple slope values ​​corresponding to each battery cell. This can improve the accuracy of battery device detection, and at the same time, it can achieve non-destructive testing of battery cells without disassembling the battery device.

[0031] In one possible implementation, the battery device is tested based on multiple slope values ​​corresponding to multiple battery cells at the target stage, including: determining whether the battery device has structural failure based on the changes in multiple slope values ​​of multiple target lines corresponding to each of the multiple battery cells at the multiple target stages.

[0032] In the embodiments of this application, the failure of the battery device structure can be determined based on the multiple slope values ​​of multiple target lines corresponding to each of the multiple battery cells at multiple target stages, which can improve the accuracy of battery device detection.

[0033] In one possible implementation, determining whether the battery device has a structural failure is based on the change in the slope value of the target line corresponding to each of the multiple battery cells at multiple target stages. This includes: determining that the battery device has a structural failure when a first battery cell exists among the multiple battery cells, wherein the slope value of the multiple target lines corresponding to the first battery cell shows a downward trend and the degree of decrease is greater than or equal to a preset degree.

[0034] In this embodiment, when multiple first battery cells in a battery device exhibit a significant decrease in slope value corresponding to multiple target stages, a structural failure of the battery device is determined. This reduces detection errors caused by data fluctuations and improves the accuracy of battery device detection.

[0035] In one possible implementation, the slope values ​​of the multiple target lines corresponding to the first battery cell exhibit a decreasing trend, and the degree of decrease is greater than or equal to a preset degree, including: the slope values ​​of the first battery cell... Among them, multiple target stages include the 1st, nth, and n+1th target stages. The 1st, nth, and n+1th target stages include the current decrease stages during the 1st, nth, and n+1th target constant voltage charging processes, respectively. K n K represents the slope value of the first battery cell in the nth target stage. n+1 K1 represents the slope value of the first battery cell in the (n+1)th target stage, and K1 represents the slope value of the first battery cell in the first target stage. 预设 This is the default value.

[0036] In this embodiment of the application, if a first battery cell exists among multiple battery cells... ≥K 预设 This can identify structural failures in the battery device and improve the accuracy of detecting structural failures in the battery device.

[0037] In one possible implementation, K 预设 ≥20%.

[0038] In this embodiment of the application, by using K 预设 A value of ≥20% can reduce the impact of data fluctuations on the test results and accurately detect whether the battery device has structural failure.

[0039] In one possible implementation, determining a battery device structural failure when a first battery cell is present among multiple battery cells includes: determining that the first battery cell has ruptured when a first battery cell is present among multiple battery cells.

[0040] In this embodiment, when a first battery cell exists among multiple battery cells, it can be determined that the first battery cell, such as its casing and / or pressure relief mechanism, has ruptured. This allows for accurate detection of whether a battery cell in the battery device has ruptured, improving the accuracy of battery cell rupture detection without disassembling the battery device and battery cells, thus facilitating the detection of battery cell rupture.

[0041] In one possible implementation, determining a battery device structural failure when a first battery cell exists among multiple battery cells includes: determining that a first fixing band is at risk of breakage when multiple first battery cells exist among multiple battery cells, wherein the multiple first battery cells are all battery cells in the first fixing band, and the battery device includes the first fixing band.

[0042] In this embodiment of the application, if there are multiple first battery cells among multiple battery cells and the battery cells fixed by the first fixing band include multiple first battery cells, it can be determined that there is a risk of breakage of the first fixing band, so that the breakage of the fixing band of the battery device can be predicted or warned in advance.

[0043] In one possible implementation, determining a structural failure of the battery device when a first battery cell exists among multiple battery cells includes: determining that the end plate of the battery device is at risk of breakage when multiple first battery cells exist among multiple battery cells, wherein the multiple first battery cells are battery cells in multiple fixed strips.

[0044] In this embodiment of the application, if there are multiple first battery cells among multiple battery cells and the multiple first battery cells exist in different fixing bands, it can be determined that there is a risk of breakage of the end plate of the battery device, so that the breakage of the end plate of the battery device can be predicted or warned in advance.

[0045] In one possible implementation, the battery device is tested based on multiple slope values ​​corresponding to multiple battery cells at the target stage, including: determining the SOH value of multiple battery cells based on multiple slope values ​​corresponding to the target lines of multiple battery cells.

[0046] In the embodiments of this application, the SOH value of each battery cell can be determined based on the slope value corresponding to each battery cell in the target stage, which can improve the accuracy of SOH detection for each battery cell in the multiple battery cells.

[0047] On the other hand, during the charging process of the battery device, the SOH of multiple battery cells can be detected, simplifying the operation of battery cell SOH detection.

[0048] In one possible implementation, the SOH of multiple battery cells is determined based on the slope values ​​of the target lines corresponding to multiple battery cells, including: determining the SOH values ​​of multiple battery cells based on the multiple slope values ​​corresponding to the target lines of the multiple battery cells and an SOH prediction model, wherein the SOH prediction model includes the correspondence between the slope values ​​of the target lines corresponding to the multiple battery cells and the SOH values.

[0049] In the embodiments of this application, the SOH value of multiple battery cells can be accurately determined by using the slope value of the target line of each battery cell in the target stage and the SOH prediction model.

[0050] Secondly, a detection device for a battery device is provided. The battery device includes multiple battery cells. The detection device includes: an acquisition unit for acquiring current and time information of the multiple battery cells in a target stage, the target stage including a current decrease stage during target constant voltage charging after charging to the charging cutoff voltage; a processing unit for determining multiple slope values ​​corresponding to the current-time function relationship of the multiple battery cells in the target stage based on the current and time information of the multiple batteries in the target stage; and a detection device for detecting the battery device based on the multiple slope values ​​corresponding to the multiple battery cells in the target stage.

[0051] In one possible implementation, the processing unit is configured to use the current of multiple battery cells at the target stage as the ordinate, and... Using the x-axis as the horizontal axis, target lines for multiple battery cells are obtained, and multiple slope values ​​corresponding to the target lines of multiple battery cells are determined, where t is the time of multiple battery cells in the target stage.

[0052] In one possible implementation, multiple battery cells are connected in series, and a processing unit is used to perform constant voltage charging on the multiple battery cells, the constant voltage charging including target constant voltage charging.

[0053] In one possible implementation, a processing unit is used to control a first charging device to perform constant voltage charging on multiple individual battery cells, the first charging device being connected to the charging ports of the multiple battery cells.

[0054] In one possible implementation, the processing unit is configured to control a second charging device to charge the entire battery device, the second charging device being connected to the charging port of the battery device; and to control the second charging device to stop charging the battery device when a single battery cell in the battery device reaches the charging cutoff voltage.

[0055] In one possible implementation, a processing unit is used to control a second charging device to perform constant current charging on the battery device.

[0056] In one possible implementation, a processing unit is used to control a third charging device to perform constant voltage charging on the entire battery device, the third charging device being connected to the charging port of the battery device.

[0057] In one possible implementation, the processing unit is used to control the third charging device to charge the entire battery device until the voltage of the battery device is less than (Vmax1+Vmax2+……VmaxN) and greater than or equal to (Vmax1+Vmax2+……VmaxN-0.5*N), where Vmax1, Vmax2, …, VmaxN are the charging cutoff voltages of multiple battery cells, and N is the number of multiple battery cells.

[0058] In one possible implementation, the processing unit is used to control the third charging device to charge the entire battery device until the voltage of the battery device is in the range of (Vmax*N-0.3*N) to (Vmax*N-0.1*N), where Vmax is the charging cutoff voltage of one of the multiple battery cells.

[0059] In one possible implementation, a processing unit is used to control a third charging device to perform constant current charging on the battery device.

[0060] In one possible implementation, an acquisition unit is used to acquire information on the current and time of each of the multiple battery cells in multiple target stages, wherein the multiple target stages are the stages of current decrease during multiple target constant voltage charging processes after multiple charging to the charging cutoff voltage.

[0061] In one possible implementation, the processing unit is configured to use the current of each of the multiple battery cells at multiple target stages as the ordinate, and... Using the x-axis as the horizontal axis, we obtain multiple target lines for each of the multiple battery cells, and determine multiple slope values ​​corresponding to the multiple target lines for each of the multiple battery cells.

[0062] In one possible implementation, the processing unit is used to determine whether the battery device has structural failure based on the changes in multiple slope values ​​of multiple target lines corresponding to each of the multiple battery cells at multiple target stages.

[0063] In one possible implementation, the processing unit is used to determine that the battery device structure has failed when a first battery cell is present among multiple battery cells, wherein the slope values ​​of multiple target lines corresponding to the first battery cell show a downward trend and the degree of decrease is greater than or equal to a preset degree.

[0064] In one possible implementation, the first battery cell's Among them, multiple target stages include the 1st, nth, and n+1th target stages. The 1st, nth, and n+1th target stages include the current decrease stages during the 1st, nth, and n+1th target constant voltage charging processes, respectively. K n K represents the slope value of the first battery cell in the nth target stage. n+1 K1 represents the slope value of the first battery cell in the (n+1)th target stage, and K1 represents the slope value of the first battery cell in the first target stage. 预设 This is the default value.

[0065] In one possible implementation, K 预设 ≥20%.

[0066] In one possible implementation, the processing unit is used to determine that the first battery cell is broken when the first battery cell is present among multiple battery cells.

[0067] In one possible implementation, the processing unit is used to determine that there is a risk of breakage in the first fixing strip when there are multiple first battery cells among multiple battery cells, wherein the multiple first battery cells are all battery cells in the first fixing strip, and the battery device includes the first fixing strip.

[0068] In one possible implementation, the processing unit is used to determine that there is a risk of breakage of the end plate of the battery device when there are multiple first battery cells among multiple battery cells, wherein the multiple first battery cells are battery cells in multiple fixed strips.

[0069] In one possible implementation, the processing unit is used to determine the SOH value of multiple battery cells based on multiple slope values ​​corresponding to the target lines of multiple battery cells respectively.

[0070] In one possible implementation, the processing unit is used to determine the SOH value of multiple battery cells based on multiple slope values ​​corresponding to the target lines of multiple battery cells and a SOH prediction model. The SOH prediction model includes the correspondence between the slope values ​​and SOH values ​​of the target lines corresponding to multiple battery cells.

[0071] Thirdly, a detection device for a battery device is provided, wherein the control device includes a memory and a processor, the memory being used to store instructions, and the processor being used to read the instructions and execute the control method as described in the first aspect and any possible implementation thereof.

[0072] Fourthly, a chip is provided, comprising: a processor for retrieving and running a computer program from a memory, causing a device on which the chip is mounted to perform a detection method as described in the first aspect and any possible implementation thereof.

[0073] Fifthly, a computer program is provided that, when executed by a computer, causes the computer to implement the detection method as described in the first aspect and any possible implementation thereof.

[0074] In a sixth aspect, a computer-readable storage medium is provided for storing a computer program that, when executed by a computer, causes the computer to implement the detection method as described in the first aspect and any possible implementation thereof.

[0075] In a seventh aspect, a computer program product is provided, including computer program instructions that, when executed by a computer, cause the computer to implement the detection method as described in the first aspect and any possible implementation thereof. Attached Figure Description

[0076] Figure 1 is a flowchart illustrating the detection method for the battery device provided in an embodiment of this application.

[0077] Figure 2 is a schematic diagram of the current change during the constant voltage charging process provided in this application.

[0078] Figure 3 is a schematic diagram of the current change during the current decrease stage in the constant voltage charging process provided in the embodiment of this application.

[0079] Figure 4 shows the current at the target stage provided in the embodiments of this application. A diagram illustrating the relationship between the two.

[0080] Figure 5 is a flowchart illustrating the detection method for the battery device provided in an embodiment of this application.

[0081] Figure 6 is a flowchart illustrating the detection method for the battery device provided in an embodiment of this application.

[0082] Figure 7 is a schematic diagram showing the connection between the first charging device and the second charging device and the battery device provided in the embodiments of this application.

[0083] Figure 8 is a flowchart illustrating the detection method for the battery device provided in an embodiment of this application.

[0084] Figure 9 is a schematic diagram of the connection between the third charging device and the battery device provided in the embodiment of this application.

[0085] Figure 10 is a flowchart illustrating the detection method of the battery device provided in the embodiments of this application.

[0086] Figure 11 is a flowchart illustrating the detection method of the battery device provided in an embodiment of this application.

[0087] Figure 12 shows the SOH prediction model provided in the embodiments of this application.

[0088] Figure 13 is a schematic block diagram of the detection device for the battery device provided in an embodiment of this application.

[0089] Figure 14 is another schematic block diagram of the detection device for the battery device provided in the embodiments of this application. Detailed Implementation

[0090] The embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to illustrate the principles of this application by way of example, but should not be used to limit the scope of this application, that is, this application is not limited to the described embodiments.

[0091] 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, "a plurality of" means two or more, unless otherwise explicitly defined. The terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing description of the drawings of this application, are intended to cover non-exclusive inclusion.

[0092] 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 alone, A and B simultaneously, or B alone. Additionally, the character " / " in this text generally indicates that the preceding and following related objects have an "or" relationship.

[0093] 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.

[0094] The directional terms used in the following description refer to the directions shown in the figures and are not intended to limit the specific structure of this application. It should also be noted in the description of this application that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0095] During battery use, it is necessary to test the battery to determine whether it meets the user's needs. For example, during use, external forces or other factors may cause structural failures in the battery, such as damage to parts of the battery cell, like welds, leading to electrolyte leakage and affecting battery performance and lifespan.

[0096] Therefore, how to accurately test batteries during their use is one of the urgent problems to be solved.

[0097] To address the aforementioned issues, this application provides a method and apparatus for detecting a battery device. The battery device includes multiple battery cells. The detection method includes: acquiring current and time information of the multiple battery cells in a target stage, where the target stage includes a current decrease phase during a target constant-voltage charging process after charging to the charging cutoff voltage; determining multiple slope values ​​corresponding to the current-time function relationship of the multiple battery cells in the target stage based on the current and time information of the multiple batteries in the target stage; and detecting the battery device based on the multiple slope values ​​corresponding to the multiple battery cells in the target stage.

[0098] The battery device detection method and detection device provided in this application can improve the accuracy of battery device detection, and can also detect the battery device during the charging process, thus simplifying the battery device detection operation.

[0099] In the embodiments of this application, the battery device may include different forms of devices for energy storage and supply, such as battery modules, battery packs, battery clusters, energy storage cabinets or boxes.

[0100] In this embodiment, the battery cell includes an electrode assembly and an electrolyte. The electrode assembly consists of a positive electrode, a negative electrode, and a separator. The battery cell primarily functions by the movement of metal ions between the positive and negative electrode plates. The positive electrode includes a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive current collector, and the uncoated positive current collector protrudes beyond the coated positive current collector, serving as the positive electrode tab. Taking a lithium-ion battery as an example, the material of the positive current collector can be aluminum, and the positive active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode includes a negative current collector and a negative active material layer. The negative active material layer is coated on the surface of the negative current collector, and the uncoated negative current collector protrudes beyond the coated negative current collector, serving as the negative electrode tab. The negative electrode current collector can be made of copper, and the negative electrode active material can be carbon or silicon, etc. To ensure that a large current can pass through without melting, there are multiple positive electrode tabs stacked together, and there are multiple negative electrode tabs stacked together. The separator can be made of PP (polypropylene) or PE (polyethylene), etc. In addition, the electrode assembly can be a wound structure or a stacked structure, and the embodiments of this application are not limited to these.

[0101] Multiple battery cells can be connected in series, parallel, or in a hybrid configuration. A hybrid configuration refers to a combination of series and parallel connections. For example, multiple battery cells can be directly assembled into a battery, or they can first be assembled into a battery module, and then the battery module can be assembled into a battery. Alternatively, multiple battery cells can first be connected in series, parallel, or in a hybrid configuration to form a battery module, and then multiple battery modules can be connected in series, parallel, or in a hybrid configuration to form a battery.

[0102] Battery cells may include lithium-ion rechargeable batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries, etc., and this application embodiment is not limited to these. Battery cells may be cylindrical, flat, cuboid, or other shapes, etc., and this application embodiment is not limited to these. Battery cells are generally classified into three types according to their packaging method: cylindrical battery cells, cuboid / square battery cells, and pouch battery cells, and this application embodiment is not limited to these.

[0103] First, the detection method of the battery device provided in the embodiments of this application will be introduced with reference to Figures 1 to 12.

[0104] Figure 1 is a schematic flowchart of the detection method for a battery device provided in an embodiment of this application. The battery device includes multiple battery cells.

[0105] 110, obtain information on the current and time of multiple battery cells at the target stage.

[0106] The target phase includes the current decrease phase during the target constant voltage charging process after charging to the charging cutoff voltage.

[0107] The charging cutoff voltage refers to the maximum voltage that a single battery cell can reach during charging.

[0108] Information on the current and time of a single battery cell during the target phase can provide information on the charging current and time during the current decrease phase of the constant voltage charging process when the battery cell reaches the target charging cutoff voltage.

[0109] The target constant voltage charging process refers to the constant voltage charging process after a single battery cell reaches its charging cutoff voltage. As an example, the target constant voltage charging process can be a continuous charging process.

[0110] The process of target constant voltage charging can include a phase of current decrease. During the current decrease phase, the current decreases over time.

[0111] As an example, individual battery cells can be charged in various ways, such as constant voltage charging and constant current constant voltage charging.

[0112] For example, when a battery cell is charged using a constant-voltage charging method, the charging voltage is constant while the current gradually decreases. The target constant-voltage charging process after reaching the charging cutoff voltage can be considered as the charging process after the battery cell voltage reaches the charging cutoff voltage during the constant-voltage charging process. The target stage, on the other hand, is the stage after the battery cell voltage reaches the charging cutoff voltage during the constant-voltage charging process.

[0113] For example, when a battery cell is charged using a constant current / constant voltage charging method, in the constant current charging stage, the battery cell is charged with a constant current. When the voltage of the battery cell reaches the charging cutoff voltage, it enters the constant voltage charging stage, where the battery cell is charged with a constant voltage and the current gradually decreases. The process of reaching the target constant voltage charging cutoff voltage can be considered the constant voltage charging stage in the constant current / constant voltage charging method. The target stage is the constant voltage charging stage in the constant current / constant voltage charging method.

[0114] For example, when a battery cell is charged in a constant current and constant voltage manner, in the constant current charging stage, the battery cell is charged with a constant current. When the voltage of the battery cell has not reached the charging cutoff voltage, it can also enter the constant voltage charging stage. In the constant voltage charging stage, the battery cell will first be charged with its upper limit of allowable current until the charging cutoff voltage is reached, and then charged with a constant voltage. When charging with a constant voltage, the current of the battery cell gradually decreases.

[0115] Generally speaking, due to the presence of polarization such as ohmic polarization, electrochemical polarization, and concentration polarization, as shown in Figure 2, the constant-voltage charging of a battery cell after reaching the charging cutoff voltage (which can be either constant-voltage charging or constant-current constant-voltage charging) can include two sub-stages: In the first sub-stage, due to the presence of electrochemical polarization and concentration polarization within the battery cell, the constant-voltage charging current remains at its upper limit of allowable current; subsequently, in the second sub-stage, the current gradually decreases. As an example, in this case, the second sub-stage of gradually decreasing current shown in Figure 2 can be considered as the target stage.

[0116] As an example, the moment when the current begins to decrease in Figure 2 is taken as time 0, and the information on the change of current of a single cell in the target stage as shown in Figure 3 is obtained.

[0117] Alternatively, a portion of the second sub-stage where the current gradually decreases as shown in Figure 2 can be taken as the target stage.

[0118] It should be understood that the current and time information of a single battery cell in the target stage can be in the form shown in Figure 3, or in numerical form, or in other forms. This application does not limit the form in which the current and time information is presented.

[0119] 120. Based on the current and time information of multiple batteries in the target stage, determine multiple slope values ​​corresponding to the current-time function relationship of multiple battery cells in the target stage.

[0120] The current-time function of a single battery cell during the target stage can be expressed as a function of m(I)-n(t), where m(I) is a function related to the current I during the target stage, and n(t) is a parameter related to the time t during the target stage. That is, the horizontal axis of this function can be either m(I) or n(t), and the vertical axis can be either m(I) or n(t).

[0121] For example, the current-time function relationship in the target stage can be: The functional relationship, whose ordinate can be... The x-axis of this function can be 1 / I.

[0122] As an example, the current-time function relationship of a single battery cell at a target stage can be obtained as a curve, and the slope value of the fitted curve can be used as the slope value of the current-time function relationship at the target stage.

[0123] As another example, the current-time function of a single battery cell at a target stage can be represented by a straight line. The slope of this line can be used as the slope of the current-time function at the target stage.

[0124] Generally speaking, based on the information of current and time during the current drop phase of a single battery cell during a target constant voltage charging process, a slope value corresponding to a current-time function relationship can be obtained.

[0125] 130. The battery device is tested based on the multiple slope values ​​corresponding to the multiple battery cells at the target stage.

[0126] In this embodiment, based on the current and time information of multiple battery cells during the current-time decrease phase of the target charging process, multiple slope values ​​corresponding to the current-time relationship function of each battery cell in the target phase can be determined. Therefore, the state of the multiple battery cells can be determined based on these multiple slope values, thereby enabling the detection of the battery device. This improves the accuracy of battery device detection and simplifies the operation of battery device detection by allowing detection during the charging process.

[0127] In some embodiments, the current-time function of a single battery cell during the target stage can be expressed as follows: The functional relationship.

[0128] That is, using the current of multiple battery cells at the target stage as the vertical axis and the current of multiple battery cells at the target stage as the horizontal axis. Using the x-axis, we obtain target lines for multiple battery cells and determine the slope values ​​corresponding to the target lines for each battery cell.

[0129] t refers to the time taken for multiple battery cells to reach the target stage.

[0130] In this application, the current at the target stage of each battery cell can be used as the vertical axis, and the current at the horizontal axis can be used as the vertical axis. Using the x-axis as the horizontal axis, the target line can be obtained, and then the slope value of the target line can be determined.

[0131] As an example, the vertical axis of the target line can be the current during the current decrease phase of the target's constant voltage charging process, and the horizontal axis can be... t represents the time of current decrease during the target constant voltage charging process.

[0132] As an example, the target line can be a curve. The slope value of the fitted curve can be used as the slope value of the target line. For example, by processing the curve of current changing with time in the target stage shown in Figure 3, the current in the target stage shown in Figure 4 is obtained. The relationship curve. Figure 4 shows the target line with the vertical axis representing the current during the constant voltage charging process, and the horizontal axis representing... t represents the time it takes for the current to decrease during the target constant voltage charging process. The slope of the fitted curve shown in Figure 4 can be used as the slope value of the target line.

[0133] As another example, the target line can also be a straight line. The slope value of this straight line can be used as the slope value of the target line. For example, the straight line could be one with the current of the target stage as the vertical axis and the horizontal axis as the vertical axis. The fitted straight line is obtained by using it as the x-axis.

[0134] Generally speaking, based on the information of current and time during the current drop phase of a single battery cell during a target constant voltage charging process, a slope value corresponding to a target line for that battery cell can be obtained.

[0135] Figure 5 is a flowchart illustrating the detection method for the battery device provided in an embodiment of this application.

[0136] 510, performs constant voltage charging on multiple individual battery cells.

[0137] Constant voltage charging includes target constant voltage charging.

[0138] Multiple battery cells are connected in series.

[0139] In this embodiment, during the constant voltage charging process of multiple battery cells, the current change trend of the multiple battery cells over time includes different situations:

[0140] In some embodiments, each of the multiple battery cells can be charged to the charging cutoff voltage, and then the multiple battery cells are subjected to constant voltage charging. That is, at the beginning of constant voltage charging, the voltage of the multiple battery cells all reach the charging cutoff voltage, and then the current of the multiple battery cells gradually decreases over time.

[0141] In this scenario, the constant-voltage charging of multiple individual battery cells is the target constant-voltage charging. The target stage for these multiple battery cells can be defined as the stage of constant-voltage charging for all of them.

[0142] In some embodiments, multiple battery cells can be charged. A portion of the battery cells are charged to a charging cutoff voltage, and then the entire battery cell system is subjected to constant-voltage charging. During constant-voltage charging, the current of this portion of battery cells gradually decreases. Another portion of battery cells is first charged to the upper limit of its allowable current to the charging cutoff voltage, and then charged at a constant voltage. During this constant-voltage charging process, the current of this other portion of battery cells gradually decreases.

[0143] In this scenario, the constant-voltage charging of this portion of battery cells is the target constant-voltage charging, and the constant-voltage charging of the other portion of battery cells after reaching the cutoff voltage (the process of charging at a constant voltage) is also the target constant-voltage charging. The target stage for this portion of battery cells is the constant-voltage charging process for that portion of battery cells, while the target stage for the other portion of battery cells is the charging process at a constant voltage for that other portion of battery cells.

[0144] In some embodiments, multiple battery cells can be charged until they are all charged to near (but less than) their respective charging cutoff voltages, and then subjected to constant-voltage charging. During constant-voltage charging, each battery cell is first charged to its respective maximum allowable current to the charging cutoff voltage, and then charged at a constant voltage, with the current of each battery cell gradually decreasing during the constant-voltage charging process.

[0145] In this scenario, the constant-voltage charging (the process of charging at a constant voltage) after multiple battery cells have been charged to their cutoff voltage is considered the target constant-voltage charging. The target stages for the multiple battery cells are the processes of charging each of those cells at a constant voltage.

[0146] Generally speaking, due to the presence of polarization such as ohmic polarization, electrochemical polarization, and concentration polarization, the constant-voltage charging of each battery cell after reaching the charging cutoff voltage (i.e., the target constant-voltage charging, which can be either constant-voltage charging or constant-current constant-voltage charging after reaching the charging cutoff voltage) can include the two sub-stages shown in Figure 2. Considering polarization, these two sub-stages are described above in Figure 2. As an example, in this case, the second sub-stage, where the current gradually decreases as shown in Figure 2, can be considered the target stage.

[0147] As an example, the moment when the current begins to decrease in Figure 2 is taken as time 0, and the information on the change of current of a single cell in the target stage as shown in Figure 3 is obtained.

[0148] Alternatively, a portion of the second sub-stage where the current gradually decreases as shown in Figure 2 can be taken as the target stage.

[0149] In this embodiment, constant voltage charging of multiple battery cells can be achieved by charging the entire battery device, or by charging multiple battery cells individually.

[0150] In this embodiment of the application, the target constant voltage charging of multiple battery cells can be achieved by performing constant voltage charging on multiple battery cells, thereby obtaining information on the current and time of multiple battery cells at the target stage.

[0151] In some embodiments, a plurality of individual battery cells are charged at a constant voltage to charge them to the charging cutoff current of the plurality of individual battery cells.

[0152] As an example, multiple battery cells have the same charging cutoff current.

[0153] In some embodiments, the charging cutoff current of a single battery cell is ≤0.05C.

[0154] In some embodiments, the charging cutoff current of a single battery cell ranges from 0.01C to 0.05C.

[0155] In some embodiments, the upper limit of the current for constant voltage charging is in the range of 0.5C to 1C.

[0156] In some embodiments, the upper limit of the current for constant voltage charging ranges from 0.7C to 1C.

[0157] 520, obtain information on the current and time of multiple battery cells at the target stage.

[0158] The target phase includes the current decrease phase during the target constant voltage charging process after charging to the charging cutoff voltage.

[0159] 530. Based on the current and time information of multiple batteries in the target stage, determine multiple slope values ​​corresponding to the current-time function relationship of multiple battery cells in the target stage.

[0160] 540. The battery device is tested based on multiple slope values ​​corresponding to multiple individual battery cells at the target stage.

[0161] The contents of steps 520 to 540 can be found in steps 110 to 130 and the relevant descriptions above, and will not be repeated here.

[0162] As described above, constant voltage charging of multiple battery cells can be performed in different ways. The following will, with reference to Figures 6 and 7, further illustrate exemplary methods for detecting battery devices when performing constant voltage charging of multiple battery cells connected in series in different ways.

[0163] Figure 6 is a flowchart illustrating the detection method for the battery device provided in an embodiment of this application.

[0164] 610, Control the second charging device to charge the entire battery device.

[0165] The second charging device is connected to the charging port of the battery device.

[0166] As shown in Figure 7, the second charging device is connected to both ends of the battery device and is used to charge the entire battery device.

[0167] 620, when a single battery cell in the battery device reaches the charging cutoff voltage, control the second charging device to stop charging the battery device.

[0168] For example, when controlling the second charging device to charge the battery device, if some battery cells reach their charging cutoff voltage while other battery cells have not been charged to their charging cutoff voltage, the second charging device is controlled to stop charging the battery device.

[0169] In this embodiment of the application, when a battery cell in the battery device reaches the charging cutoff voltage, controlling the second charging device to stop charging the battery device can reduce the risk of overcharging of that battery cell, thereby reducing the impact on the performance and lifespan of the battery device.

[0170] In some embodiments, a second charging device can be controlled to perform constant current charging on the battery device.

[0171] In this embodiment of the application, the battery device is charged at a constant current by a second charging device until a single battery cell reaches the charging cutoff voltage, which can improve the charging efficiency of the battery device, reduce the charging time, and thus reduce the time required to detect the battery device.

[0172] On the other hand, multiple battery cells are connected in series and the entire battery device is charged with constant current through a second charging device. The charging current of multiple battery cells is consistent, which facilitates the control of constant current charging among multiple battery cells.

[0173] 630, control the first charging device to perform constant voltage charging on multiple individual battery cells.

[0174] The first charging device is connected to the charging ports of multiple individual battery cells.

[0175] Constant voltage charging includes target constant voltage charging.

[0176] As shown in Figure 7, the first charging device is connected to both ends of each of the multiple battery cells to charge the multiple battery cells separately.

[0177] In other words, in this embodiment, the second charging device can be controlled to charge multiple battery cells. When some of the battery cells are charged to the charging cutoff voltage, the first charging device is then controlled to individually perform constant voltage charging on each of the multiple battery cells. During the constant voltage charging process, the current of the portion of battery cells gradually decreases; another portion of battery cells are first charged to the charging cutoff voltage at their upper limit of allowable current, and then charged at a constant voltage. During the constant voltage charging process, the current of this other portion of battery cells gradually decreases.

[0178] In this scenario, the constant-voltage charging of this portion of battery cells is the target constant-voltage charging, and the constant-voltage charging of the other portion of battery cells after reaching the cutoff voltage (the process of charging at a constant voltage) is also the target constant-voltage charging. The target stage for this portion of battery cells is the constant-voltage charging process for that portion of battery cells, while the target stage for the other portion of battery cells is the charging process at a constant voltage for that other portion of battery cells.

[0179] Generally, due to the presence of polarization such as ohmic polarization, electrochemical polarization, and concentration polarization, the constant-voltage charging (i.e., target constant-voltage charging) of each battery cell after reaching the charging cutoff voltage can include the two sub-stages shown in Figure 2. Considering polarization, the content of these two sub-stages can be referred to the description in Figure 2 above. As an example, in this case, the second sub-stage where the current gradually decreases, as shown in Figure 2, can be considered the target stage. Alternatively, a portion of the second sub-stage where the current gradually decreases, as shown in Figure 2, can also be considered the target stage.

[0180] In this embodiment of the application, by controlling the first charging device to charge multiple battery cells individually, it is convenient to independently control the charging of multiple battery cells, which can reduce the possibility of overcharging multiple battery cells, thereby improving the performance and service life of the battery device.

[0181] 640, obtain information on the current and time of multiple battery cells at the target stage.

[0182] The target phase includes the current decrease phase during the target constant voltage charging process after charging to the charging cutoff voltage.

[0183] 650. Based on the current and time information of multiple batteries in the target stage, determine multiple slope values ​​corresponding to the current-time function relationship of multiple battery cells in the target stage.

[0184] 660. The battery device is tested based on the multiple slope values ​​corresponding to the multiple battery cells at the target stage.

[0185] The contents of steps 640 to 660 can be found in steps 110 to 130 and the relevant descriptions above, and will not be repeated here.

[0186] Figure 8 is a flowchart illustrating the detection method for the battery device provided in an embodiment of this application.

[0187] 810, Control the third charging device to charge the entire battery device.

[0188] The third charging device is connected to the charging port of the battery device.

[0189] In this embodiment, as shown in FIG9, the third charging device is connected to both ends of the battery device and is used to charge the entire battery device.

[0190] In this embodiment, by controlling a third charging device to perform constant voltage charging on the entire battery device, it can be applied to the scenario where current charging piles charge battery devices such as battery packs. This eliminates the need to modify the charging port of the charging pile, reducing the modification cost for battery device testing.

[0191] In some embodiments, a third charging device is controlled to charge the entire battery device until the voltage of the battery device is less than (Vmax1+Vmax2+……VmaxN) and greater than or equal to (Vmax1+Vmax2+……VmaxN-0.5*N).

[0192] Where Vmax1, Vmax2, ..., VmaxN are the charging cutoff voltages of multiple battery cells, and N is the number of multiple battery cells.

[0193] In this embodiment of the application, by controlling the third charging device as a whole to charge the battery device to a voltage between (Vmax1+Vmax2+……VmaxN-0.5*N) and (Vmax1+Vmax2+……VmaxN), the possibility of overcharging individual battery cells in the battery device can be reduced, thereby reducing the impact of overcharging individual battery cells on the performance and lifespan of the battery device.

[0194] In some embodiments, a third charging device is controlled to charge the entire battery device until the voltage of the battery device is in the range of (Vmax*N-0.3*N) to (Vmax*N-0.1*N), where Vmax is the charging cutoff voltage of one of the multiple battery cells.

[0195] In this embodiment, the charging cut-off voltage of the multiple battery cells in the battery device is the same.

[0196] In this embodiment of the application, by controlling the third charging device to charge the battery device to a voltage between (Vmax*N-0.3*N) and (Vmax*N-0.1*N), the possibility of overcharging individual battery cells in the battery device can be reduced, thereby reducing the impact of overcharging individual battery cells on the performance and lifespan of the battery device.

[0197] In some embodiments, a third charging device can be controlled to perform constant current charging on the battery device.

[0198] In this embodiment of the application, the battery device is charged at a constant current by a third charging device until a single battery cell reaches the charging cutoff voltage, which can improve the charging efficiency of the battery device, reduce the charging time, and thus reduce the time required to detect the battery device.

[0199] On the other hand, multiple battery cells are connected in series, and the entire battery device is charged with constant current through a single charging device. The charging current of multiple battery cells is consistent, which facilitates the control of constant current charging among multiple battery cells.

[0200] 820, controls the third charging device to perform constant voltage charging on the battery device.

[0201] Constant voltage charging includes target constant voltage charging.

[0202] In this embodiment, the third charging device is controlled to perform constant voltage charging on the battery device.

[0203] In other words, a third charging device can be controlled to charge multiple battery cells, such as through constant current charging. When all battery cells are charged to near their respective charging cutoff voltages (i.e., below their respective charging cutoff voltages), the third charging device can be controlled to perform constant voltage charging on the multiple battery cells. During constant voltage charging, each battery cell is first charged to its respective maximum allowable current to the charging cutoff voltage, and then charged at a constant voltage. During the constant voltage charging process, the current of each battery cell gradually decreases.

[0204] In this scenario, the constant-voltage charging (the process of charging at a constant voltage) after multiple battery cells have been charged to their cutoff voltage is considered the target constant-voltage charging. The target stages for the multiple battery cells are the processes of charging each of those cells at a constant voltage.

[0205] Generally, due to the presence of polarization such as ohmic polarization, electrochemical polarization, and concentration polarization, the constant-voltage charging (i.e., target constant-voltage charging) of each battery cell after reaching the charging cutoff voltage can include the two sub-stages shown in Figure 2. Considering polarization, these two sub-stages are described above in Figure 2. As an example, in this case, the second sub-stage where the current gradually decreases, as shown in Figure 2, can be considered the target stage. Alternatively, a portion of the second sub-stage where the current gradually decreases, as shown in Figure 2, can also be considered the target stage.

[0206] As an example, the moment when the current begins to decrease in Figure 2 is taken as time 0, and the information on the change of current of a single cell in the target stage as shown in Figure 3 is obtained.

[0207] 830, obtain information on the current and time of multiple battery cells at the target stage.

[0208] The target phase includes the current decrease phase during the target constant voltage charging process after charging to the charging cutoff voltage.

[0209] 840, with the current of multiple battery cells at the target stage as the vertical axis and the current of multiple battery cells at the target stage as the horizontal axis. Using the x-axis, we obtain target lines for multiple battery cells and determine the slope values ​​corresponding to the target lines for each battery cell.

[0210] t refers to the time taken for multiple battery cells to reach the target stage.

[0211] 850, the battery device is tested based on the multiple slope values ​​corresponding to the target lines of multiple battery cells.

[0212] The contents of steps 830 to 850 can be found in steps 110 to 130 and the relevant descriptions above, and will not be repeated here.

[0213] In some embodiments, it can be determined whether the battery device has structural failure based on the change in the slope value of the target line corresponding to each of the multiple battery cells.

[0214] In some embodiments, the State of Health (SOH) value of a plurality of battery cells is determined based on the slope value of the target line corresponding to each of the plurality of battery cells.

[0215] The following description, in conjunction with Figures 10 and 11, provides an exemplary description of the methods provided in this application for determining whether the structure of a battery device has failed and for determining the SOH value of multiple battery cells.

[0216] Figure 10 is a flowchart illustrating the detection method of the battery device provided in the embodiments of this application.

[0217] 1010, obtain the current and time information of each of the multiple battery cells in multiple target stages.

[0218] The multiple target stages refer to the stages of current decrease during multiple target constant voltage charging processes after multiple charging to the charging cutoff voltage.

[0219] In some embodiments, the multiple target stages may be all the target stages experienced by each battery cell, i.e., all the number of target constant voltage charging processes experienced; or they may be a portion of the total number of target stages experienced by the battery cell.

[0220] In some embodiments, information on the current and time of each cell in each target phase across all number of target phases can be obtained.

[0221] As an example, information on the current and time of the current drop phase during each target constant voltage charging process can be obtained for each battery cell.

[0222] As an example, information on the current and time of a single battery cell in the Nth target stage can be obtained, as well as information on the current and time of a single battery cell in the N+1th target stage.

[0223] For example, information on the current and time of the current decrease phase during the Nth target constant voltage charging process can be obtained separately, as well as information on the current and time of the current decrease phase during the N+1th target constant voltage charging process.

[0224] In this embodiment of the application, by acquiring the current and time information of each battery cell in multiple target stages, it is convenient to determine the multiple slope values ​​of multiple target lines corresponding to each battery cell in multiple target stages. Then, based on the changing trend of the multiple slope values ​​corresponding to each battery cell, it is possible to accurately determine whether the battery device has experienced structural failure, without disassembling the battery device, etc., which facilitates the detection of structural failure of the battery device.

[0225] 1020, with the current of each battery cell in multiple target stages as the vertical axis and the current of each battery cell as the horizontal axis, and the current of each battery cell in multiple target stages as the vertical axis. Using the x-axis as the horizontal axis, we obtain multiple target lines for each of the multiple battery cells, and determine multiple slope values ​​corresponding to the multiple target lines for each of the multiple battery cells.

[0226] That is, in this embodiment, the current of each target stage among multiple target stages corresponding to each battery cell is used as the vertical axis, and the current of each target stage is used as the horizontal axis. Using the horizontal axis, multiple target lines corresponding to multiple target stages for each battery cell are obtained, and then multiple slope values ​​of these multiple target lines are determined.

[0227] Using the current of each battery cell at a target stage as the ordinate, and the current corresponding to that target stage as the axis... Using the x-axis as the horizontal axis, a target line can be obtained, and then the slope value of that target line can be determined.

[0228] As an example, the current during the current drop phase of each battery cell during the Nth target constant voltage charging process can be used as an example. Using the vertical and horizontal axes as the ordinate and the horizontal axis, the target line corresponding to the Nth target stage of each battery cell is obtained, and the slope value of the target line corresponding to the Nth target stage of each battery cell is determined; and using the current and time of the current drop stage during the N+1th target constant voltage charging process of each battery cell as the ordinate and the horizontal axis, the target line corresponding to the N+1th target stage of each battery cell is obtained, and the slope value of the target line corresponding to the N+1th target stage of each battery cell is determined.

[0229] In this embodiment of the application, by determining multiple slope values ​​of multiple target lines corresponding to multiple battery cells at multiple target stages, the structural failure of the battery device can be determined by the changing trend of multiple slope values ​​corresponding to each battery cell. This can improve the accuracy of battery device detection, and at the same time, it can achieve non-destructive testing of battery cells without disassembling the battery device.

[0230] 1030. Based on the changes in the slope values ​​of multiple target lines corresponding to each of the multiple battery cells at multiple target stages, determine whether the battery device has structural failure.

[0231] Structural failures of battery devices can include cell breakage, strap breakage, end plate breakage, etc.

[0232] In the embodiments of this application, the failure of the battery device structure can be determined based on the multiple slope values ​​of multiple target lines corresponding to each of the multiple battery cells at multiple target stages, which can improve the accuracy of battery device detection.

[0233] In some embodiments, when a first battery cell exists among multiple battery cells, a battery device structural failure is determined, wherein the slope values ​​of multiple target lines corresponding to the first battery cell show a downward trend and the degree of decrease is greater than or equal to a preset degree.

[0234] As an example, if the slope value corresponding to the (N+1)th target stage of the first battery cell is less than the slope value corresponding to the Nth target stage, and the absolute value of the difference between the two is greater than or equal to a preset reduction amount, the battery device is determined to have suffered a structural failure. For instance, if the slope value corresponding to the current decrease stage during the (N+1)th target constant voltage charging process of the first battery cell is less than the slope value corresponding to the current decrease stage during the Nth target constant voltage charging process, and the absolute value of the difference between the two is greater than or equal to a preset reduction amount, the battery device is determined to have suffered a structural failure.

[0235] In this embodiment, if a first battery cell exists in the battery device where multiple slope values ​​decrease significantly across multiple target stages, a structural failure of the battery device is determined. This reduces detection errors caused by data fluctuations and improves the accuracy of battery device detection.

[0236] In some embodiments, the slope values ​​of the multiple target lines corresponding to the first battery cell exhibit a decreasing trend, and the degree of decrease is greater than or equal to a preset degree, including: the slope values ​​of the first battery cell... Among them, multiple target stages include the 1st, nth, and n+1th target stages. The 1st, nth, and n+1th target stages include the current decrease stages during the 1st, nth, and n+1th target constant voltage charging processes, respectively. K n K represents the slope value of the first battery cell in the nth target stage. n+1 K1 represents the slope value of the first battery cell in the (n+1)th target stage, and K1 represents the slope value of the first battery cell in the first target stage. 预设 This is the default value.

[0237] In this embodiment of the application, if a first battery cell exists among multiple battery cells... It can identify structural failures in the battery device and improve the accuracy of detecting structural failures in the battery device.

[0238] In some embodiments, K 预设 ≥20%.

[0239] In this embodiment of the application, by using K 预设 A value of ≥20% can reduce the impact of data fluctuations on the test results and accurately detect whether the battery device has structural failure.

[0240] In some embodiments, if a first battery cell is present among a plurality of battery cells, the first battery cell is determined to be ruptured.

[0241] A battery cell rupture can be understood as the rupture of the outer structure that protects and seals the internal components of the battery cell, such as the electrolyte, electrodes, and circuitry. For example, a battery cell rupture may include the rupture of the battery cell's casing and / or a mechanism on the casing that provides sealing and protection for the internal components, such as a pressure relief mechanism.

[0242] In the embodiments of this application, the number of first battery cells can be one or more.

[0243] In this embodiment, when a first battery cell exists among multiple battery cells, it can be determined that the first battery cell, such as its casing or pressure relief mechanism, has ruptured. This allows for accurate detection of whether a battery cell in the battery device has ruptured, improving the accuracy of battery cell rupture detection. It also eliminates the need to disassemble the battery device and battery cells, facilitating the detection of battery cell rupture.

[0244] In some embodiments, when there are multiple first battery cells among multiple battery cells, it is determined that there is a risk of breakage of the first fixing band, wherein the multiple first battery cells are all battery cells in the first fixing band, and the battery device includes the first fixing band.

[0245] The first fixing strap is used to fix the battery cells.

[0246] A fixing strap is a structure used to fix and bind individual battery cells, mainly serving the functions of fixing and insulation.

[0247] The battery assembly may include at least one retaining strap. For example, the battery assembly includes six retaining straps, each for securing 10 battery cells.

[0248] In other words, in this embodiment, if multiple battery cells fixed by the first fixing band rupture, such as if the first fixing band fixes 10 battery cells and 5 of them rupture, it indicates that the first fixing band is also at risk of breakage. For example, under external impact, the first fixing band and the multiple battery cells within it may experience structural failure, such as the first fixing band breaking or the casing or pressure relief mechanism of the multiple battery cells within it rupturing.

[0249] In this embodiment of the application, if there are multiple first battery cells among multiple battery cells and the battery cells fixed by the first fixing band include multiple first battery cells, it can be determined that there is a risk of breakage of the first fixing band, so that the breakage of the fixing band of the battery device can be predicted or warned in advance.

[0250] In some embodiments, when there are multiple first battery cells among multiple battery cells, it is determined that there is a risk of breakage of the end plate of the battery device, wherein the multiple first battery cells are battery cells in multiple fixing strips, and the battery device includes multiple fixing strips.

[0251] The end plates of a battery device are generally located at both ends of the battery device, such as the left and right ends or the top and bottom ends. They mainly serve to protect and fix the individual battery cells.

[0252] As an example, when the battery device is subjected to external force, the battery cells fixed by 3 of the 6 fixing straps of the battery device include the first battery cell that has broken. For example, there is 1 first battery cell in fixing strap 1, 2 first battery cells in fixing strap 2, and 1 first battery cell in fixing strap 3.

[0253] In this embodiment of the application, if there are multiple first battery cells among multiple battery cells and the multiple first battery cells exist in different fixing bands, it can be determined that there is a risk of breakage of the end plate of the battery device, so that the breakage of the end plate of the battery device can be predicted or warned in advance.

[0254] Figure 11 is a flowchart illustrating the detection method of the battery device provided in an embodiment of this application.

[0255] 1110, Obtain information on the current and time of multiple individual battery cells during the target stage.

[0256] The target phase includes the current decrease phase during the target constant voltage charging process after charging to the charging cutoff voltage.

[0257] 1120, with the current of multiple battery cells at the target stage as the vertical axis and the horizontal axis as the vertical axis. Using the x-axis, we obtain target lines for multiple battery cells and determine the slope values ​​corresponding to the target lines for each battery cell.

[0258] t refers to the time taken for multiple battery cells to reach the target stage.

[0259] The contents of steps 1110 and 1120 can be found in the relevant descriptions above, and will not be repeated here.

[0260] 1130. Based on the multiple slope values ​​corresponding to the target lines of multiple battery cells, determine the SOH value of multiple battery cells.

[0261] In some embodiments, the SOH values ​​of multiple battery cells are determined based on multiple slope values ​​corresponding to the target lines of multiple battery cells and a SOH prediction model. The SOH prediction model includes the correspondence between the slope values ​​of the target lines of multiple battery cells and the SOH values.

[0262] There is a correlation between the slope value of a battery cell at the target stage and the SOH value of that battery cell. Therefore, the SOH value of a battery cell can be determined based on the slope value of that battery cell at the target stage.

[0263] For example, the formula relating the slope value of a battery cell at the target stage to its state of equilibrium (SOH) is: K = a(1-SOH) + b. Here, K is the slope value of the battery cell at the target stage, and SOH is the SOH value of the battery cell. The SOH value of a battery cell can be calculated using this formula.

[0264] In this embodiment, the SOH value of each battery cell can be determined based on the slope value of the target line corresponding to each of the multiple battery cells at the target stage, thereby improving the accuracy of SOH detection for each of the multiple battery cells. Furthermore, during the charging process of the battery device, SOH detection of multiple battery cells can be achieved, simplifying the operation of individual battery cell SOH detection.

[0265] In some embodiments, the SOH value of each battery cell can be determined based on the slope value of the target line corresponding to each battery cell in the target stage and the SOH prediction model, wherein the SOH prediction model includes the correspondence between the slope value of the target line corresponding to the multiple battery cells and the SOH value.

[0266] SOH prediction models can include machine learning models, correspondence formulas, correspondence tables, or correspondence graphs.

[0267] As an example, Figure 12 shows a SOH prediction model in the form of a correspondence graph. Based on the slope value determined in step 1120 and the SOH prediction model shown in Figure 12, the SOH value of each battery cell can be determined.

[0268] In the embodiments of this application, the SOH prediction model for multiple battery cells can be one or more. For example, if multiple battery cells are of the same model, the SOH prediction model for multiple battery cells can be one.

[0269] In the embodiments of this application, the SOH value of multiple battery cells can be accurately determined by using the slope value of the target line of each battery cell in the target stage and the SOH prediction model.

[0270] In some embodiments, the target stage includes the stage after the current decreases during the target constant voltage charging process, 100 seconds later, and t=0 corresponds to the moment when the current begins to decrease during the target constant voltage charging process.

[0271] The stage after the current drops by 100s, i.e., t≥100s, corresponds to For example, the interval after the 100th second of the charging current decrease in Figure 3 corresponds to the interval in Figure 4. The range.

[0272] As can be seen from Figure 4, Within the interval, the current follows The trend of change is close to a straight line, that is, the target line is close to a straight line, and the slope value of the target line can be determined more accurately.

[0273] As an example, information on the current and time of each battery cell after the 100th second of current drop during multiple target constant voltage charging processes can be obtained. Then, based on the current and time information of each battery cell after multiple 100th seconds during multiple target constant voltage charging processes, multiple slope values ​​of multiple target lines corresponding to each battery cell can be determined to detect whether each battery cell is broken.

[0274] As an example, information on the current and time after the 100th second of the current drop during the Mth target constant voltage charging process of multiple battery cells can be obtained to determine the slope value corresponding to the Mth target stage of multiple battery cells, and detection can be performed on multiple battery cells to determine the SOH of multiple battery cells.

[0275] In this embodiment, the target line determined by the current and time of the battery cell after the current drops by 100 seconds during the target constant voltage charging process is closer to a straight line. By using the slope value of this target line that is close to a straight line, the battery device can be detected more accurately.

[0276] In some embodiments, the target phase includes the phase after the current decreases during the target constant voltage charging process at 150 seconds, and t=0 corresponds to the moment when the current begins to decrease during the target constant voltage charging process.

[0277] The stage after the current drops by 150s, i.e., t≥150s, corresponds to Approximately ≤0.082. As can be seen from Figure 4, in... Within the range of approximately 0.08, the target line is closer to a straight line, thus allowing for a more accurate determination of the slope value of the target line.

[0278] In this embodiment of the application, the target line determined by the current and time after the current drops for 150 seconds during the target constant voltage charging process is closer to a straight line. By using the slope value of this target line that is close to a straight line, the battery device can be detected more accurately.

[0279] On the other hand, the current and time after the current drops 150 seconds during the target constant voltage charging process, or the current and time after the current drops 150 seconds during the target constant voltage charging process, greatly reduce the amount of data when detecting individual battery cells, thus reducing data overhead.

[0280] It should be understood that in the various embodiments of this application, the order of the above-mentioned processes does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0281] The detection method of the battery system according to the embodiments of this application has been described in detail above. The detection device of the battery device according to the embodiments of this application will be described in detail below with reference to FIG13 and FIG14. The technical features described in the method embodiments are applicable to the following device embodiments.

[0282] Figure 13 is a schematic block diagram of a battery device detection apparatus provided in an embodiment of this application. As shown in Figure 13, the detection apparatus 4000 includes some or all of the following components.

[0283] The battery device includes multiple battery cells. The detection device 4000 includes an acquisition unit 4010 and a processing unit 4020.

[0284] The acquisition unit 4010 is used to acquire information on the current and time of multiple battery cells in the target stage, which includes the current decrease stage during the target constant voltage charging process after charging to the charging cutoff voltage; the processing unit 4020 is used to determine multiple slope values ​​corresponding to the current-time function relationship of multiple battery cells in the target stage based on the current and time information of multiple batteries in the target stage; and to detect the battery device based on the multiple slope values ​​corresponding to the multiple battery cells in the target stage.

[0285] In some embodiments, the processing unit 4020 is configured to use the current of multiple battery cells at a target stage as the vertical axis and... Using the x-axis as the horizontal axis, target lines for multiple battery cells are obtained, and multiple slope values ​​corresponding to the target lines of multiple battery cells are determined, where t is the time of multiple battery cells in the target stage.

[0286] In some embodiments, multiple battery cells are connected in series, and the processing unit 4020 is used to perform constant voltage charging on the multiple battery cells, the constant voltage charging including target constant voltage charging.

[0287] In some embodiments, the processing unit 4020 is used to control a first charging device to perform constant voltage charging on multiple individual battery cells, the first charging device being connected to the charging ports of the multiple battery cells.

[0288] In some embodiments, the processing unit 4020 is configured to control a second charging device to charge the entire battery device, the second charging device being connected to the charging port of the battery device; and to control the second charging device to stop charging the battery device when a single battery cell in the battery device reaches the charging cutoff voltage.

[0289] In some embodiments, the processing unit 4020 is configured to control the second charging device to perform constant current charging on the battery device.

[0290] In some embodiments, the processing unit 4020 is used to control a third charging device to perform constant voltage charging on the entire battery device, the third charging device being connected to the charging port of the battery device.

[0291] In some embodiments, the processing unit 4020 is used to control the third charging device to charge the entire battery device to the point that the voltage of the battery device is less than (Vmax1+Vmax2+……VmaxN) and greater than or equal to (Vmax1+Vmax2+……VmaxN-0.5*N), where Vmax1, Vmax2, …, VmaxN are the charging cutoff voltages of the multiple battery cells, and N is the number of the multiple battery cells.

[0292] In some embodiments, the processing unit 4020 is used to control the third charging device to charge the entire battery device, so that the voltage of the battery device is charged to a value range of (Vmax*N-0.3*N) to (Vmax*N-0.1*N), where Vmax is the charging cutoff voltage of one of the multiple battery cells.

[0293] In some embodiments, the processing unit 4020 is configured to control a third charging device to perform constant current charging on the battery device.

[0294] In some embodiments, the acquisition unit 4010 is used to acquire information on the current and time of each of the multiple battery cells in multiple target stages, wherein the multiple target stages are the stages of current decrease during multiple target constant voltage charging after multiple charging to the charging cutoff voltage.

[0295] In some embodiments, the processing unit 4020 is configured to use the current of each of the plurality of battery cells at multiple target stages as the vertical axis and... Using the x-axis as the horizontal axis, we obtain multiple target lines for each of the multiple battery cells, and determine multiple slope values ​​corresponding to the multiple target lines for each of the multiple battery cells.

[0296] In some embodiments, the processing unit 4020 is configured to determine whether the battery device has a structural failure based on the changes in multiple slope values ​​of multiple target lines corresponding to each of the multiple battery cells at multiple target stages.

[0297] In some embodiments, the processing unit 4020 is configured to determine a battery device structural failure when a first battery cell is present among a plurality of battery cells, wherein the slope values ​​of the plurality of target lines corresponding to the first battery cell exhibit a downward trend and the degree of decrease is greater than or equal to a preset degree.

[0298] In some embodiments, the first battery cell Among them, multiple target stages include the 1st, nth, and n+1th target stages. The 1st, nth, and n+1th target stages include the current decrease stages during the 1st, nth, and n+1th target constant voltage charging processes, respectively. K n K represents the slope value of the first battery cell in the nth target stage. n+1 K1 represents the slope value of the first battery cell in the (n+1)th target stage, and K1 represents the slope value of the first battery cell in the first target stage. 预设 This is the default value.

[0299] In some embodiments, K 预设 ≥20%.

[0300] In some embodiments, the processing unit 4020 is configured to determine that a first battery cell is ruptured when a first battery cell is present among a plurality of battery cells.

[0301] In some embodiments, the processing unit 4020 is configured to determine that there is a risk of breakage of the first fixing band when there are multiple first battery cells among multiple battery cells, wherein the multiple first battery cells are all battery cells in the first fixing band, and the battery device includes the first fixing band.

[0302] In some embodiments, the processing unit 4020 is configured to determine that there is a risk of breakage of the end plate of the battery device when there are multiple first battery cells among multiple battery cells, wherein the multiple first battery cells are battery cells in multiple fixed strips.

[0303] In some embodiments, the processing unit 4020 is configured to determine the SOH value of a plurality of battery cells based on a plurality of slope values ​​corresponding to the target lines of the plurality of battery cells respectively.

[0304] In some embodiments, the processing unit 4020 is configured to determine the SOH value of multiple battery cells based on multiple slope values ​​corresponding to the target lines of multiple battery cells and a SOH prediction model. The SOH prediction model includes the correspondence between the slope values ​​and SOH values ​​of the target lines corresponding to multiple battery cells.

[0305] It should be understood that the above and other operations and / or functions of the various modules in the detection device 4000 of the battery device are to implement the corresponding processes in the various methods of Figures 1 to 12, and for the sake of brevity, they will not be described in detail here.

[0306] Figure 14 shows a schematic block diagram of a battery device detection apparatus 5000 according to an embodiment of this application. As shown in Figure 14, the detection apparatus 5000 includes a processor 5010 and a memory 5020, wherein the memory 5020 is used to store instructions, and the processor 5010 is used to read the instructions and execute the methods of the various embodiments of this application described above based on the instructions.

[0307] The memory 5020 can be a separate device independent of the processor 5010, or it can be integrated into the processor 5010.

[0308] Optionally, as shown in Figure 9, the detection device 5000 of the battery device may further include a transceiver 5030, and the processor 5010 can control the transceiver 5030 to communicate with other devices. Specifically, it can send information or data to other devices, or receive information or data sent by other devices.

[0309] It should be understood that the processor in the embodiments of this application may be an integrated circuit chip with signal processing capabilities. In implementation, the steps of the above method embodiments can be completed by integrated logic circuits in the processor's hardware or by instructions in software form. The processor described above can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly embodied in the execution of a hardware decoding processor, or executed by a combination of hardware and software modules in the decoding processor. The software modules can be located in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. The storage medium is located in memory, and the processor reads information from the memory and, in conjunction with its hardware, completes the steps of the above method.

[0310] It is understood that the memory in the embodiments of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous linked dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM). It should be noted that the memory used in the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0311] Optionally, embodiments of this application also provide an electrical device, which includes a battery device and a detection device provided in embodiments of this application.

[0312] This application also provides a computer-readable storage medium for storing computer programs.

[0313] Optionally, the computer-readable storage medium can be applied to the detection device of the battery device in the embodiments of this application, and the computer program, when run on a computer, causes the computer to execute the corresponding processes implemented by the detection device in the various methods of the embodiments of this application. For the sake of brevity, it will not be described in detail here.

[0314] This application also provides a computer program product, including computer program instructions.

[0315] Optionally, the computer program product can be applied to the battery device detection device in the embodiments of this application, and the computer program instructions, when run on a computer, cause the computer to execute the corresponding processes implemented by the battery device detection device in the various methods of the embodiments of this application. For the sake of brevity, they will not be described in detail here.

[0316] This application also provides a computer program.

[0317] Optionally, the computer program can be applied to the battery device detection device in the embodiments of this application. When the computer program is run on a computer, it causes the computer to execute the corresponding processes implemented by the battery device detection device in the various methods of the embodiments of this application. For the sake of brevity, it will not be described in detail here.

[0318] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0319] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0320] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection involved in the embodiments of this application may be through some interfaces, and the indirect coupling or communication connection of devices or units may be electrical, mechanical, or other forms.

[0321] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0322] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0323] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, ROM, RAM, magnetic disks, or optical disks.

[0324] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. 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 method for detecting a battery device, characterized in that, The battery device includes multiple battery cells, and the detection method includes: Information on the current and time of the plurality of battery cells in the target stage is obtained. The target stage includes the current decrease stage during the target constant voltage charging process after charging to the charging cutoff voltage. Based on the current and time information of the multiple batteries in the target stage, determine multiple slope values ​​corresponding to the current-time function relationship of the multiple battery cells in the target stage. The battery device is tested based on the multiple slope values ​​corresponding to the multiple battery cells at the target stage.

2. The detection method according to claim 1, characterized in that, The step of determining multiple slope values ​​corresponding to the current-time function relationship of multiple battery cells in the target stage based on the current and time information of the multiple batteries in the target stage includes: Using the current of the plurality of battery cells in the target stage as the ordinate, and the current of the battery cells in the target stage as the indicative axis, ..., the current of the battery cells in the target stage, the Using the x-axis as the horizontal axis, the target lines of the plurality of battery cells are obtained respectively, and the slope values ​​corresponding to the target lines of the plurality of battery cells are determined respectively, where t is the time of the plurality of battery cells in the target stage.

3. The detection method according to claim 1 or 2, characterized in that, The plurality of battery cells are connected in series. Before acquiring information on the current and time of the plurality of battery cells at the target stage, the method includes: The plurality of individual battery cells are subjected to constant voltage charging, the constant voltage charging including target constant voltage charging.

4. The detection method according to claim 3, characterized in that, The constant voltage charging of the plurality of battery cells includes: The first charging device is controlled to perform constant voltage charging on each of the plurality of battery cells individually. The first charging device is connected to the charging port of each of the plurality of battery cells.

5. The detection method according to claim 4, characterized in that, Before controlling the first charging device to individually perform constant voltage charging on each of the plurality of battery cells, the detection method further includes: The second charging device is controlled to charge the entire battery device, and the second charging device is connected to the charging port of the battery device; If any battery cell in the battery device reaches the charging cutoff voltage, the second charging device is controlled to stop charging the battery device.

6. The detection method according to claim 4, characterized in that, The control of the second charging device to charge the battery device as a whole includes: The second charging device is controlled to perform constant current charging on the battery device.

7. The detection method according to claim 3, characterized in that, The constant voltage charging of the plurality of battery cells includes: The third charging device is controlled to perform constant voltage charging on the entire battery device, and the third charging device is connected to the charging port of the battery device.

8. The detection method according to claim 7, characterized in that, Before the third charging device is used to perform constant voltage charging on the entire battery device, the detection method further includes: The third charging device is controlled to charge the entire battery device until the voltage of the battery device is less than (Vmax1+Vmax2+……VmaxN) and greater than or equal to (Vmax1+Vmax2+……VmaxN-0.5*N), where Vmax1, Vmax2, …, VmaxN are the charging cutoff voltages of the plurality of battery cells, and N is the number of the plurality of battery cells.

9. The detection method according to claim 8, characterized in that, The control of the third charging device to charge the battery device as a whole includes: The third charging device is controlled to perform constant current charging on the battery device.

10. The detection method according to any one of claims 2 to 9, characterized in that, The acquisition of current and time information of the plurality of battery cells at the target stage includes: Information on the current and time of each of the plurality of battery cells in a plurality of target stages is obtained, wherein the plurality of target stages are the stages in which the current decreases during multiple target constant voltage charging processes after multiple charging to the charging cutoff voltage.

11. The detection method according to claim 10, characterized in that, Using the current of the plurality of battery cells in the target stage as the ordinate, and the current of the battery cells in the target stage as the indicative axis, ..., the current of the battery cells in the target stage, the Using the x-axis as the horizontal axis, target lines for the plurality of battery cells are obtained, and multiple slope values ​​corresponding to the target lines of the plurality of battery cells are determined, including: Using the current of each of the plurality of battery cells in the plurality of target stages as the ordinate, and... Using the x-axis as the horizontal axis, multiple target lines are obtained for each of the multiple battery cells, and multiple slope values ​​are determined for each of the multiple target lines in the multiple battery cells.

12. The detection method according to claim 11, characterized in that, The step of detecting the battery device based on the multiple slope values ​​corresponding to the multiple battery cells at the target stage includes: Based on the changes in the slope values ​​of multiple target lines corresponding to each of the multiple battery cells in the multiple target stages, it is determined whether the battery device has structural failure.

13. The detection method according to claim 12, characterized in that, The step of determining whether the battery device has a structural failure based on the change in the slope value of the target line corresponding to each of the plurality of battery cells in the plurality of target stages includes: If a first battery cell exists among the plurality of battery cells, the battery device structure is determined to be faulty, wherein the slope value of the plurality of target lines corresponding to the first battery cell shows a downward trend and the degree of decrease is greater than or equal to a preset degree.

14. The detection method according to claim 13, characterized in that, The slope values ​​of the plurality of target lines corresponding to the first battery cell exhibit a decreasing trend, and the degree of decrease is greater than or equal to a preset degree, including: The first battery cell The plurality of target stages include the 1st, nth, and n+1th target stages, wherein the 1st, nth, and n+1th target stages include the current decrease phases during the 1st, nth, and n+1th target constant voltage charging processes, K n K represents the slope value corresponding to the first battery cell in the nth target stage. n+1 K1 is the slope value corresponding to the first battery cell in the (n+1)th target stage, K1 is the slope value corresponding to the first battery cell in the first target stage, K 预设 This is the default value.

15. The detection method according to claim 13 or 14, characterized in that, In the case where a first battery cell exists among the plurality of battery cells, determining that the battery device structure has failed includes: If the first battery cell is present among the plurality of battery cells, it is determined that the first battery cell is ruptured.

16. The detection method according to any one of claims 13 to 15, characterized in that, In the case where a first battery cell exists among the plurality of battery cells, determining that the battery device structure has failed includes: In the case where there are multiple first battery cells among the plurality of battery cells, it is determined that there is a risk of breakage of the first fixing strap, wherein the plurality of first battery cells are all battery cells in the first fixing strap, and the battery device includes the first fixing strap.

17. The detection method according to any one of claims 13 to 16, characterized in that, In the case where a first battery cell exists among the plurality of battery cells, determining that the battery device structure has failed includes: If multiple first battery cells exist among the multiple battery cells, it is determined that there is a risk of breakage of the end plate of the battery device, wherein the multiple first battery cells are battery cells in multiple fixed strips.

18. The detection method according to any one of claims 2 to 17, characterized in that, The step of detecting the battery device based on the multiple slope values ​​corresponding to the multiple battery cells at the target stage includes: The SOH value of the multiple battery cells is determined based on the multiple slope values ​​corresponding to the target lines of the multiple battery cells.

19. The detection method according to claim 18, characterized in that, Determining the SOH of the plurality of battery cells based on the slope values ​​of the target lines corresponding to the plurality of battery cells includes: Based on the multiple slope values ​​corresponding to the target lines of the multiple battery cells and the SOH prediction model, the SOH values ​​of the multiple battery cells are determined. The SOH prediction model includes the correspondence between the slope values ​​of the target lines corresponding to the multiple battery cells and the SOH values.

20. A detection device for a battery device, characterized in that, The battery device includes multiple battery cells, and the detection device includes: The acquisition unit is used to acquire information on the current and time of the plurality of battery cells in the target stage, wherein the target stage includes the stage of current decrease during the target constant voltage charging process after charging to the charging cutoff voltage; The processing unit determines, based on the current and time information of the multiple batteries during the target stage, multiple slope values ​​corresponding to the current-time functional relationship of the multiple battery cells during the target stage; and The battery device is used to detect the battery device based on the multiple slope values ​​corresponding to the multiple battery cells in the target stage.

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