A lithium precipitation prediction method and device

Abstract

This disclosure relates to a method and apparatus for predicting lithium plating. It includes acquiring a set of charging parameters for a lithium battery under calibrated and target rate parameters. Based on the charging parameter set, it determines the thickness change difference at a specified charge level. Based on the charging parameter set, it obtains a calibrated differential parameter set and a target differential parameter set, and determines the lithium plating capacity at the specified charge level based on these two sets. Based on the charging parameter set, the thickness change difference at the specified charge level, and the lithium plating capacity, it determines an expression for the lithium plating capacity at the target rate parameter. Acquiring the thickness change value and battery capacity of the lithium battery utilizes physical characteristics to ensure simplicity and efficiency in data acquisition during the detection process, while also reducing cost. Determining the lithium plating capacity expression at the target rate parameter based on the thickness change value and battery capacity allows for qualitative detection and analysis of the lithium plating capacity, ensuring high efficiency and accuracy in lithium plating capacity detection.

Description

Technical Field

[0001] The embodiments in this specification belong to the field of battery analysis technology, and in particular relate to a method and apparatus for predicting lithium plating. Background Technology

[0002] Currently, most lithium-ion batteries use graphite as the negative electrode. During use, due to overuse or increased aging, lithium plating can occur on the negative electrode surface during charging. This plating not only causes capacity loss but also the generated lithium dendrites can puncture the separator, posing a safety hazard. Therefore, lithium plating detection is crucial for ensuring battery safety and performance.

[0003] Currently, most lithium plating detection methods for lithium batteries are based on electrochemical methods, such as impedance-capacitance method and negative electrode potential detection method, which have the problems of cumbersome operation and high testing cost. Summary of the Invention

[0004] The embodiments of this disclosure provide a method and apparatus for predicting lithium plating.

[0005] In a first aspect of this disclosure, a method for predicting lithium plating is provided. The method includes obtaining a set of charging parameters for a lithium battery at a calibrated rate parameter and a target rate parameter. The charging parameter set includes multiple subsets of charging parameters, each subset including a thickness variation value and at least one of a calibrated battery capacity at the calibrated rate parameter and a target battery capacity at the target rate parameter. The method further includes determining a thickness variation difference of the lithium battery at a specified charge level based on the charging parameter set. The method also includes obtaining a calibrated differential parameter set and a target differential parameter set based on the charging parameter set, and determining the lithium plating capacity of the lithium battery at the specified charge level based on the calibrated differential parameter set and the target differential parameter set. Furthermore, the method includes determining an expression for the lithium plating capacity of the lithium battery at the target rate parameter based on the charging parameter set, the thickness variation difference of the lithium battery at the specified charge level, and the lithium plating capacity.

[0006] In a second aspect of this disclosure, a lithium plating prediction apparatus is provided. The apparatus includes a data acquisition module configured to acquire a set of charging parameters for a lithium battery under a calibrated rate parameter and a target rate parameter. The charging parameter set includes multiple subsets of charging parameters, each subset including a thickness variation value and at least one of a calibrated battery capacity under the calibrated rate parameter and a target battery capacity under the target rate parameter. The apparatus also includes a thickness calculation module configured to determine, based on the charging parameter set, the thickness variation difference of the lithium battery at a specified charge level. The apparatus further includes a lithium plating calculation module configured to obtain a calibrated differential parameter set and a target differential parameter set based on the charging parameter set, and to determine the lithium plating capacity of the lithium battery at the specified charge level based on the calibrated differential parameter set and the target differential parameter set. Furthermore, the apparatus includes a formula construction module configured to determine an expression for the lithium plating capacity of the lithium battery at the target rate parameter based on the charging parameter set, the thickness variation difference of the lithium battery at the specified charge level, and the lithium plating capacity.

[0007] In a third aspect of this disclosure, a computer program product is provided, comprising a computer program that is executed by a processor to implement the method according to the first aspect.

[0008] In a fourth aspect of this disclosure, a machine-readable storage medium is provided. The machine-readable storage medium stores machine-executable instructions, which are executed by a processor to implement the method provided according to a first aspect of this disclosure.

[0009] It should be understood that the description in the Summary of the Invention section is not intended to limit the key or essential features of the embodiments of this disclosure, nor is it intended to restrict the scope of this disclosure. Other features of this disclosure will become readily apparent from the following description. Attached Figure Description

[0010] The above and other features, advantages, and aspects of the embodiments of this disclosure will become more apparent from the accompanying drawings and the following detailed description. In the drawings, the same or similar reference numerals denote the same or similar elements, wherein:

[0011] Figure 1 A schematic diagram of an example environment in which some embodiments of this disclosure may be implemented is shown;

[0012] Figure 2 A flowchart of a lithium plating prediction method according to some embodiments of the present disclosure is shown;

[0013] Figure 3 A schematic diagram showing the relationship between thickness variation values ​​and battery capacity in some embodiments of this disclosure is shown;

[0014] Figure 4A schematic diagram showing the relationship between thickness variation and charge amount in some embodiments of this disclosure is shown;

[0015] Figure 5 A schematic diagram showing the relationship between the differential value of thickness variation and battery capacity in some embodiments of this disclosure is shown;

[0016] Figure 6 A block diagram of a lithium plating prediction apparatus according to some embodiments of the present disclosure is shown; and

[0017] Figure 7 A block diagram of an electronic device that can implement several embodiments of the present disclosure is shown. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0019] The terms “comprising” and “having”, and any variations thereof, in this specification, claims, and the foregoing drawings are intended to cover a non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus. Depending on the context, the word “if” as it applies herein may be interpreted as “when”, “when”, “in response to determination”, or “in response to detection”.

[0020] As mentioned above, during the charging process of a lithium battery, lithium ions escape from the positive electrode and migrate to the graphite surface of the negative electrode, where they intercalate between the crystal planes of the graphite lattice to form LiC6. When the number of lithium intercalation sites in the graphite exceeds the number of sites that can be intercalated, or when the rate of increase in lithium concentration exceeds the normal rate of intercalation, lithium ions will deposit on the graphite surface to form metallic lithium. Because lithium grows in a dendritic form, this not only causes a change in the volume of the lithium battery, but the generated dendritic lithium may also puncture the separator, thus causing safety issues for the lithium battery.

[0021] Currently, most lithium plating detection methods for lithium batteries are based on electrochemical detection methods. In addition to the impedance-capacity method and negative electrode potential detection method mentioned above, there are also coulombic efficiency method, electrochemical impedance method and voltage relaxation method. These detection methods require real-time acquisition of the electrical signal of the lithium battery during the lithium plating detection process, which makes the operation more cumbersome and the detection equipment used also has the problem of high cost.

[0022] To address this, embodiments of this disclosure propose a method for predicting lithium plating. The method includes obtaining a set of charging parameters for a lithium battery under a calibrated rate parameter and a target rate parameter. The charging parameter set includes multiple subsets of charging parameters, each subset including a thickness variation value and at least one of the calibrated battery capacity under the calibrated rate parameter and the target battery capacity under the target rate parameter. The method further includes determining the thickness variation difference of the lithium battery at a specified charge level based on the charging parameter set. The method also includes obtaining a calibrated differential parameter set and a target differential parameter set based on the charging parameter set, and determining the lithium plating capacity of the lithium battery at the specified charge level based on the calibrated differential parameter set and the target differential parameter set. Furthermore, the method includes determining an expression for the lithium plating capacity of the lithium battery at the target rate parameter based on the charging parameter set, the thickness variation difference of the lithium battery at the specified charge level, and the lithium plating capacity.

[0023] This method allows for the acquisition of thickness variation and battery capacity values ​​of lithium batteries under different rate parameters. By utilizing the physical characteristics of lithium batteries, the simplicity and efficiency of data acquisition during the testing process can be ensured, and the cost is lower compared to electrochemical testing equipment. Furthermore, based on the thickness variation and battery capacity values ​​under different rate parameters, the lithium plating capacity expression of the lithium battery at the target rate parameter can be determined. This lithium plating capacity expression can then be used to qualitatively detect and analyze the lithium battery's lithium plating capacity, thereby ensuring the efficiency and accuracy of lithium plating capacity detection.

[0024] Figure 1 Schematic diagrams are shown illustrating example environments in which some embodiments of this disclosure can be implemented. For example... Figure 1As shown, the example environment 100 may include a lithium battery testing device 101. This device 101 is used to acquire the thickness change value and battery capacity of the lithium battery under test when an operator performs charge-discharge tests on the lithium battery under test using a battery testing cabinet. Here, when the operator performs charge-discharge tests on the lithium battery under test using the battery testing cabinet, the operator can perform charging tests based on a specified rate parameter, such as a rate parameter of 1C, to charge the lithium battery under test from 0% charge to 100% charge at a constant current of 1C. The operator can then determine whether the lithium battery under test has been charged to the required charge amount for the test based on the voltage corresponding to the charge amount. In some embodiments of this disclosure, the lithium battery under test can also be charged based on a specified rate parameter and the required charge amount for the test, and is not limited thereto.

[0025] It is understood that the lithium battery testing equipment 101 may include a thickness detection device and a battery capacity detection device. The thickness detection device may be a thickness sensor well-known in the art, used to acquire the thickness change values ​​of the lithium battery under test at multiple times during a charging test process according to specified rate parameters. The battery capacity detection device may be a battery tester well-known in the art, used to acquire the battery capacity of the lithium battery under test at multiple times during a charging test process according to specified rate parameters.

[0026] It should be noted that when using the battery testing cabinet to perform charge and discharge tests on the lithium battery under test, after the lithium battery under test has been charged based on the specified rate parameters, the staff can disassemble the lithium battery under test after the charging test to determine the calibrated rate parameters corresponding to the lithium battery under test when no lithium plating occurs after charging. In some implementations, the lithium battery under test can be charged sequentially at rates of 1C, 1.5C, 2C, and 2.5C. After the charging tests, the lithium battery is disassembled. If no lithium plating occurs after charging at rate 1C, and lithium plating occurs after charging at rate 1.5C, then rate 1C can be determined as the calibrated rate parameter corresponding to the absence of lithium plating after charging. In this case, disassembly of the lithium battery after charging at rate 2C and rate 2.5C is unnecessary. In some embodiments of this disclosure, the calibrated rate parameter corresponding to the absence of lithium plating after charging can also be determined by the operator based on experience or historical test results; this is not a limitation.

[0027] Example environment 100 also includes a processing terminal 102, which establishes a communication connection with lithium battery testing equipment 101 to acquire multiple thickness change values ​​and multiple battery capacities collected by the lithium battery testing equipment 101 when the lithium battery under test is charged and tested according to specified rate parameters. Here, the specified rate parameters include the calibration rate parameters and target rate parameters mentioned above. For example, the calibration rate parameter can be 1C, and the target rate parameter can be one or more of 1.5C, 2C, and 2.5C.

[0028] In addition, after obtaining the thickness change value and battery capacity of the lithium battery under test at a specified rate parameter, the processing terminal 102 can also determine the lithium plating capacity expression of the lithium battery under test at a target rate parameter based on the thickness change value and battery capacity of the lithium battery under test at the specified rate parameter. In order to qualitatively obtain the lithium plating capacity of the lithium battery under test at the target rate parameter and different charge amounts by using the lithium plating capacity expression of the lithium battery under test at the target rate parameter.

[0029] In some embodiments of this disclosure, the processing terminal 102 may be a smartphone, tablet computer, desktop computer, laptop computer, notebook computer, ultra-mobile personal computer (UMPC), handheld computer, PC device, personal digital assistant (PDA), routing device, virtual reality device, etc., or it may be a hardware server, virtual server, cloud server, routing device, gateway device, etc.

[0030] This method allows for the acquisition of thickness variation and battery capacity values ​​of lithium batteries under different rate parameters. By utilizing the physical characteristics of lithium batteries, the simplicity and efficiency of data acquisition during the testing process can be ensured, and the cost is lower compared to electrochemical testing equipment. Furthermore, based on the thickness variation and battery capacity values ​​under different rate parameters, the lithium plating capacity expression of the lithium battery at the target rate parameter can be determined. This lithium plating capacity expression can then be used to qualitatively detect and analyze the lithium battery's lithium plating capacity, thereby ensuring the efficiency and accuracy of lithium plating capacity detection.

[0031] It should be understood that the architecture and functionality in example environment 100 are described for illustrative purposes only and do not imply any limitation on the scope of this disclosure. Embodiments of this disclosure can also be applied to other environments with different architectures and / or functionalities.

[0032] Figure 2 A flowchart of a lithium plating prediction method according to some embodiments of the present disclosure is shown. Method 200 may be, for example, by... Figure 1 The processing terminal 102 in the example environment 100 shown executes. For example... Figure 2 As shown in block 202, method 200 can obtain a set of charging parameters for the lithium battery under the calibrated rate parameter and the target rate parameter. Here, the set of charging parameters for the lithium battery under the calibrated rate parameter and the target rate parameter can be obtained by the processing terminal by integrating multiple thickness variation values ​​and multiple battery capacities of the lithium battery under the calibrated rate parameter and the target rate parameter collected by the lithium battery testing device 101 in the example environment 100 described above. This set of charging parameters includes multiple subsets of charging parameters, each subset including a thickness variation value and at least one of the calibrated battery capacity of the lithium battery under the calibrated rate parameter and the target battery capacity of the lithium battery under the target rate parameter. It is understandable that lithium batteries do not undergo lithium plating when charged based on the calibrated rate parameters, but do after charging based on the target rate parameters. Because the thickness change of the lithium battery increases after lithium plating, a subset of the charging parameter set includes the thickness change value and the target battery capacity at the target rate parameters. The remaining subsets of the charging parameter set include the thickness change value, the calibrated battery capacity at the calibrated rate parameters, and the target battery capacity at the target rate parameters. It should be noted that in each subset of charging parameters including the thickness change value, the calibrated battery capacity at the calibrated rate parameters, and the target battery capacity at the target rate parameters, the calibrated battery capacity at the calibrated rate parameters is greater than the target battery capacity at the target rate parameters because lithium batteries are more susceptible to voltage polarization and lithium plating when charged at the target rate parameters.

[0033] In one example, a subset of the charging parameters in the charging parameter set includes a thickness variation of 40 μm, a target battery capacity of 2.6 Ah at a target rate of 2.5C, and a rated battery capacity of 3.3 Ah at a rated rate of 1C; and a subset of the charging parameters in the charging parameter set includes a thickness variation of 70 μm and a target battery capacity of 3.5 Ah at a target rate of 2.5C.

[0034] Please see Figure 3 The diagram shown illustrates the relationship between thickness variation values ​​and battery capacity according to some embodiments of the present disclosure, such as... Figure 3As shown, the relationship between thickness variation and battery capacity 300 includes curves showing the variation of thickness and battery capacity of lithium batteries at rate parameters of 1C, 1.5C, 2C, and 2.5C (the horizontal axis corresponds to battery capacity in Ah, and the vertical axis corresponds to thickness variation in μm). The calibrated rate parameter can be 1C, and the target rate parameters include 1.5C, 2C, and 2.5C. It can be seen that the maximum calibrated battery capacity of the lithium battery at the calibrated rate parameter is closer to the rated capacity of the lithium battery. The maximum thickness variation of the lithium battery at the target rate parameter is greater than the maximum thickness variation of the lithium battery at the calibrated rate parameter. Furthermore, thickness variations exceeding the maximum thickness variation of the lithium battery at the calibrated rate parameter only correspond to the target battery capacity at the target rate parameter.

[0035] In box 204, method 200 can determine the thickness variation difference of the lithium battery under a specified charge amount based on a set of charging parameters. Here, the specified charge amount can be any charge amount within a preset charge amount range, which can be set to 0.1 to 0.9, but is not limited to this range.

[0036] In some implementations, the processing terminal can determine the calibrated charge corresponding to each charging parameter subset based on the calibrated battery capacity of the lithium battery in each subset at the calibrated rate parameter and the maximum value among the calibrated battery capacities of all lithium batteries at the calibrated rate parameter. Here, the calibrated charge corresponding to each charging parameter subset can be the ratio between the calibrated battery capacity of the corresponding lithium battery in the subset at the calibrated rate parameter and the maximum value among the calibrated battery capacities of all lithium batteries at the calibrated rate parameter, and the calibrated charge corresponding to each charging parameter subset is between 0 and 1.

[0037] Subsequently, the processing terminal can further determine the target charge corresponding to each charging parameter subset based on the target battery capacity of the lithium battery in each charging parameter subset at the target rate parameter and the maximum value among the target battery capacities of all lithium batteries at the target rate parameter. Here, the target charge corresponding to each charging parameter subset can be the ratio between the target battery capacity of the corresponding lithium battery in the charging parameter subset at the target rate parameter and the maximum value among the target battery capacities of all lithium batteries at the target rate parameter, and the target charge corresponding to each charging parameter subset is between 0 and 1.

[0038] It should be noted that after determining the calibrated charge amount and the target charge amount corresponding to each subset of charging parameters, the correspondence between the calibrated charge amount and the thickness change value can be determined based on the calibrated charge amount and the thickness change value corresponding to each subset of charging parameters, and the correspondence between the target charge amount and the thickness change value can be determined based on the target charge amount and the thickness change value corresponding to each subset of charging parameters.

[0039] Subsequently, the processing terminal can determine the thickness variation difference of the lithium battery under a specified charge level based on the thickness variation values ​​in each subset of charging parameters, the calibrated charge level corresponding to each subset of charging parameters, and the target charge level. Here, the specified charge level can be consistent with any one of the calibrated charge levels, and this specified charge level can also be consistent with any one of the target charge levels. That is, there are multiple consistent charge levels between all calibrated charge levels and all target charge levels, and the specified charge level can be any one of these multiple consistent charge levels.

[0040] In one example, the processing terminal can determine the thickness change value based on a specified charge amount, in a subset of charging parameters containing the calibrated battery capacity of the corresponding lithium battery at a calibrated rate parameter, and in a subset of charging parameters containing the target battery capacity of the corresponding lithium battery at a target rate parameter, and use the difference between the two thickness change values ​​as the thickness change difference of the lithium battery at the specified charge amount.

[0041] Please see Figure 4 The diagram shown illustrates the relationship between thickness variation and charge amount according to some embodiments of the present disclosure, such as... Figure 4 As shown, the relationship between thickness variation and charge 400 includes curves showing the variation of thickness and charge of a lithium battery at rate parameters of 1C, 1.5C, 2C, and 2.5C (the horizontal axis corresponds to charge, and the vertical axis corresponds to thickness variation, in μm). The calibrated rate parameter can be 1C, and the target rate parameters include 1.5C, 2C, and 2.5C. It can be seen that, taking a target rate parameter of 2.5C and a specified charge between 0.8 and 1 (e.g., 0.9) as an example... It can be expressed as the difference in thickness change between the lithium battery at the target rate parameter 2.5C and the specified charge amount 0.9 and the thickness change at the calibrated rate parameter 1C and the specified charge amount 0.9.

[0042] In block 206, method 200 can obtain a calibration differential parameter set and a target differential parameter set based on a charging parameter set, and determine the lithium plating capacity of the lithium battery at a specified charge level based on the calibration differential parameter set and the target differential parameter set. In some implementations, when the processing terminal obtains the calibration differential parameter set and the target differential parameter set based on the charging parameter set, it can determine the calibration thickness change differential value corresponding to the calibration battery capacity of each lithium battery at the calibration rate parameter based on the thickness change value in each charging parameter subset and the calibration battery capacity of the lithium battery at the calibration rate parameter.

[0043] In one example, taking the charging parameter set of lithium batteries under the calibrated rate parameter and the target rate parameter as an example, the number of lithium batteries with the calibrated battery capacity under the calibrated rate parameter is N. The calibrated battery capacity of the N lithium batteries under the calibrated rate parameter can be arranged in ascending order. Based on the calibrated battery capacity of the (i+1)th lithium battery under the calibrated rate parameter, the thickness change value corresponding to the calibrated battery capacity of the (i+1)th lithium battery under the calibrated rate parameter, the calibrated battery capacity of the (i-1)th lithium battery under the calibrated rate parameter, and the thickness change value corresponding to the calibrated battery capacity of the (i-1)th lithium battery under the calibrated rate parameter, the differential value of the calibrated thickness change corresponding to the calibrated battery capacity of the ith lithium battery under the calibrated rate parameter can be calculated, where i is a positive integer greater than 1 and less than N. The calculation method can be found in the formula (1) shown below.

[0044] (1)

[0045] In the above formula, This can be the differential value of the calibration thickness change corresponding to the calibration capacity of the i-th lithium battery under the calibration rate parameters. This can be the thickness change value corresponding to the rated battery capacity of the (i+1)th lithium battery under the rated rate parameters. This can be the rated battery capacity of the (i+1)th lithium battery under the rated rate parameters. This can be the thickness change value corresponding to the rated battery capacity of the (i-1)th lithium battery under the rated rate parameters. It can be the rated battery capacity of the (i-1)th lithium battery under the rated rate parameters.

[0046] It should be noted that the differential value of the calibration thickness change corresponding to the calibration capacity of the first lithium battery under the calibration rate parameter can be calculated from the calibration capacity of the second lithium battery under the calibration rate parameter, the thickness change value corresponding to the calibration capacity of the second lithium battery under the calibration rate parameter, the calibration capacity of the first lithium battery under the calibration rate parameter, and the thickness change value corresponding to the calibration capacity of the first lithium battery under the calibration rate parameter. The calculation method can be found in formula (2) shown below:

[0047] (2)

[0048] In the above formula, This can be the differential value of the calibrated thickness change corresponding to the calibrated battery capacity of the first lithium battery under the calibrated rate parameters. This can be the thickness change value corresponding to the rated battery capacity of the second lithium battery under the rated rate parameters. This can be used as the calibrated battery capacity of the second lithium battery under the calibrated rate parameters. This can be the thickness change value corresponding to the rated battery capacity of the first lithium battery under the rated rate parameters. This can be the calibrated battery capacity of the first lithium battery under the calibrated rate parameters.

[0049] Furthermore, the differential value of the calibration thickness change corresponding to the calibration capacity of the Nth lithium battery under the calibration rate parameter can be calculated from the calibration capacity of the Nth lithium battery under the calibration rate parameter, the thickness change value corresponding to the calibration capacity of the Nth lithium battery under the calibration rate parameter, the calibration capacity of the (N-1)th lithium battery under the calibration rate parameter, and the thickness change value corresponding to the calibration capacity of the (N-1)th lithium battery under the calibration rate parameter. The calculation method can be found in formula (3) shown below:

[0050] (3)

[0051] In the above formula, This can be the differential value of the calibrated thickness change corresponding to the calibrated battery capacity of the Nth lithium battery under the calibrated rate parameters. This can be the thickness change value corresponding to the rated battery capacity of the Nth lithium battery under the rated rate parameters. This can be the calibrated battery capacity of the Nth lithium battery under the calibrated rate parameters. This can be the thickness change value corresponding to the rated battery capacity of the (N-1)th lithium battery under the rated rate parameters. It can be the rated battery capacity of the N-1th lithium battery under the rated rate parameters.

[0052] Of course, the differential value of the calibration thickness change corresponding to the calibration battery capacity of each lithium battery under the calibration rate parameter in some embodiments of this disclosure can also be obtained by performing a 9th-order polynomial fitting and differentiation process based on the thickness change value in each charging parameter subset and the calibration battery capacity of the lithium battery under the calibration rate parameter, and is not limited to this.

[0053] Subsequently, the processing terminal can obtain a calibration differential parameter set based on the calibrated battery capacity of each lithium battery under the calibrated rate parameters and the differential value of the calibration thickness change corresponding to the calibrated battery capacity of each lithium battery under the calibrated rate parameters. Here, the calibration differential parameter set may include the calibrated battery capacity of each lithium battery under the calibrated rate parameters arranged in ascending order, and the differential value of the calibration thickness change corresponding to the calibrated battery capacity of each lithium battery under the calibrated rate parameters.

[0054] Furthermore, the processing terminal can also determine the differential value of the target thickness change corresponding to the target battery capacity of each lithium battery at the target rate parameter, based on the thickness change values ​​in each subset of charging parameters and the target battery capacity of the lithium battery at the target rate parameter. For details on determining the differential value of the target thickness change corresponding to the target battery capacity of each lithium battery at the target rate parameter, please refer to the above; further details will not be elaborated here.

[0055] Subsequently, the processing terminal can also obtain a target differential parameter set based on the target battery capacity of each lithium battery under the target rate parameter and the differential value of the target thickness change corresponding to the target battery capacity of each lithium battery under the target rate parameter. Here, the target differential parameter set may include the target battery capacity of each lithium battery under the target rate parameter, arranged in ascending order, and the differential value of the target thickness change corresponding to the target battery capacity of each lithium battery under the target rate parameter.

[0056] In some implementations, when determining the lithium plating capacity of a lithium battery at a specified charge level based on a calibration differential parameter set and a target differential parameter set, the processing terminal can determine the maximum value among all calibrated thickness change differential values ​​based on the calibration differential parameter set. Here, the maximum value among all calibrated thickness change differential values ​​can be understood as the critical threshold for the thickness change differential value corresponding to when lithium plating is about to occur in the lithium battery. When the thickness change differential value exceeds the maximum value among all calibrated thickness change differential values, it indicates that the corresponding lithium battery has already undergone lithium plating; and when the thickness change differential value does not exceed the maximum value among all calibrated thickness change differential values, it indicates that the corresponding lithium battery has not yet undergone lithium plating.

[0057] Subsequently, the processing terminal can determine the target battery capacity corresponding to the maximum value among all calibrated thickness change differential values ​​in the target differential parameter set, and use this target battery capacity as the first battery capacity corresponding to the lithium battery starting to undergo lithium plating at the target rate parameter. Here, the target thickness change differential value corresponding to the target battery capacity in the target differential parameter set is consistent with the maximum value among all calibrated thickness change differential values.

[0058] Please see Figure 5 The diagram shown illustrates the relationship between the differential value of thickness variation and battery capacity according to some embodiments of the present disclosure, such as... Figure 5As shown, the relationship between the differential value of thickness change and battery capacity includes curves showing the variation of the differential value of thickness change and the change of charge for lithium batteries at rate parameters of 1C, 1.5C, 2C, and 2.5C (the horizontal axis corresponds to the differential value of thickness change, in μm, and the vertical axis corresponds to the charge, in Ah). The calibrated rate parameter can be 1C, and the target rate parameters include 1.5C, 2C, and 2.5C. It can be seen that, taking a target rate parameter of 2.5C as an example, the first battery capacity determined based on the maximum value among all calibrated differential values ​​of thickness change in the target differential parameter set can be 2.6 Ah.

[0059] Subsequently, the processing terminal can further, based on the correspondence between each target charge and target battery capacity obtained when determining the thickness change difference of the lithium battery under the specified charge, use the target battery capacity corresponding to the specified charge as the second battery capacity corresponding to the lithium battery after charging under the specified charge, and determine the lithium plating capacity of the lithium battery under the specified charge based on the second battery capacity and the first battery capacity. In one example, the lithium plating capacity of the lithium battery under the specified charge can be the difference between the second battery capacity and the first battery capacity.

[0060] In box 208, method 200 can determine the lithium plating capacity expression of the lithium battery at a target rate parameter based on the charging parameter set, the thickness change difference of the lithium battery under a specified charge, and the lithium plating capacity. Here, the lithium plating capacity expression of the lithium battery at the target rate parameter includes the correspondence between the lithium plating capacity and the thickness change difference. The corresponding lithium plating capacity can be obtained by combining the thickness change difference of the lithium battery under the required charge at the test rate parameter with the lithium plating capacity expression of the lithium battery at the target rate parameter.

[0061] This method allows for the acquisition of thickness variation and battery capacity values ​​of lithium batteries under different rate parameters. By utilizing the physical characteristics of lithium batteries, the simplicity and efficiency of data acquisition during the testing process can be ensured, and the cost is lower compared to electrochemical testing equipment. Furthermore, based on the thickness variation and battery capacity values ​​under different rate parameters, the lithium plating capacity expression of the lithium battery at the target rate parameter can be determined. This lithium plating capacity expression can then be used to qualitatively detect and analyze the lithium battery's lithium plating capacity, thereby ensuring the efficiency and accuracy of lithium plating capacity detection.

[0062] In some implementations, when the processing terminal determines the lithium plating capacity expression of the lithium battery at a target rate parameter based on a set of charging parameters, the thickness variation difference of the lithium battery at a specified charge level, and the lithium plating capacity, it can determine the lithium plating capacity difference of the lithium battery at the specified charge level based on the calibrated battery capacity and the target battery capacity corresponding to the specified charge level. Here, the calibrated battery capacity corresponding to the specified charge level can be obtained from the correspondence between each calibrated charge level and the calibrated battery capacity obtained when determining the thickness variation difference of the lithium battery at the specified charge level; the target battery capacity corresponding to the specified charge level can be obtained from the correspondence between each target charge level and the target battery capacity obtained when determining the thickness variation difference of the lithium battery at the specified charge level. In one example, the lithium plating capacity difference of the lithium battery at the specified charge level can be the difference between the calibrated battery capacity and the target battery capacity corresponding to the specified charge level.

[0063] Subsequently, the processing terminal can also determine the lithium plating capacity expression of the lithium battery under the target rate parameter based on the charging parameter set, the thickness change difference of the lithium battery under a specified charge, the lithium plating capacity and the lithium plating capacity difference.

[0064] In some implementations, when the processing terminal determines the lithium plating capacity expression of the lithium battery at a target rate parameter based on a set of charging parameters, the thickness change difference of the lithium battery at a specified charge, the lithium plating capacity, and the lithium plating capacity difference, it can determine the graphite expansion rate of the lithium battery based on the maximum value of the rated battery capacity of all lithium batteries at the calibrated rate parameter and the maximum value of the thickness change value of all lithium batteries at the calibrated rate parameter. Here, the graphite expansion rate of the lithium battery has an approximately linear relationship with the thickness change value and the rated battery capacity when the lithium battery is charged based on the calibrated rate parameter. In one example, the graphite expansion rate of the lithium battery can be the ratio between the maximum value of the thickness change value of all lithium batteries at the calibrated rate parameter and the maximum value of the rated battery capacity of all lithium batteries at the calibrated rate parameter.

[0065] Subsequently, the processing terminal can substitute the graphite expansion rate of the lithium battery, the thickness change difference of the lithium battery under a specified charge, the lithium plating capacity, and the lithium plating capacity difference into the preset lithium plating capacity expression to calculate the parameters to be solved in the preset lithium plating capacity expression. Here, the preset lithium plating capacity expression can be found in formula (4) shown below:

[0066] (4)

[0067] In the above formula, The value of A can be the thickness variation of the lithium battery under a specified charge, where A is the parameter to be solved. This can be the graphite expansion rate of a lithium battery. This can be defined as the lithium plating capacity of a lithium battery under a specified charge level. This can be the difference in lithium plating capacity of a lithium battery under a specified charge level.

[0068] It should be noted that the preset lithium plating capacity expression can be obtained by combining the following equations (5) and (6):

[0069] (5)

[0070] (6)

[0071] In the above formula, The value of A can be the thickness variation of the lithium battery under a specified charge, where A is the parameter to be solved. This can be the graphite expansion rate of a lithium battery. This can be defined as the lithium plating capacity of a lithium battery under a specified charge level. This can be the difference in lithium plating capacity of a lithium battery under a specified charge level. This can be the graphite lithium intercalation capacity of a lithium battery without lithium plating. It can be the lithium intercalation capacity of the negative electrode during lithium plating in a lithium battery.

[0072] Subsequently, the processing terminal can determine the lithium-ion battery's lithium-ion capacity expression at the target rate parameter based on a preset lithium-ion capacity expression and the parameters to be solved in the preset lithium-ion capacity expression. In one example, the calculated parameters to be solved and the graphite expansion rate can be substituted into the preset lithium-ion capacity expression to obtain the lithium-ion battery's lithium-ion capacity expression at the target rate parameter.

[0073] In some embodiments of this disclosure, taking a calibration rate parameter of 1C, a target rate parameter of 2.5C, and a specified charge of 0.9 as an example, the thickness change difference of the lithium battery at the specified charge of 0.9 is calculated to be 17.45 μm, the graphite expansion rate of the lithium battery is 14 μm / Ah, the lithium plating capacity of the lithium battery at the target rate parameter of 2.5C and the specified charge of 0.9 is 1.02 Ah, and the lithium plating capacity difference of the lithium battery at the target rate parameter of 2.5C and the specified charge of 0.9 is 0.52 Ah. By substituting into the above formula (4), the parameter A to be solved is obtained as 38.25 μm / Ah, and then the expression for the lithium plating capacity of the lithium battery at the target rate parameter of 2.5C is obtained, which can be referred to in the following formula (7):

[0074] (7)

[0075] In some implementations, after determining the lithium plating capacity expression of the lithium battery at the target rate parameter, the processing terminal can also obtain the target charge amount based on testing requirements. This target charge amount can be any one of multiple consistent charge amounts between all the calibrated charge amounts mentioned above and all the target charge amounts. The processing terminal then determines the thickness variation difference and lithium plating capacity difference of the lithium battery at this target charge amount. For details on determining the thickness variation difference and lithium plating capacity difference of the lithium battery at the target charge amount, please refer to the above description; further elaboration will not be repeated here.

[0076] Subsequently, the processing terminal can substitute the thickness change difference and lithium plating capacity difference of the lithium battery under the target charge into the lithium plating capacity expression of the lithium battery under the target rate parameter to calculate the lithium plating capacity of the lithium battery under the target rate parameter and the target charge, thereby quickly realizing the qualitative analysis of the lithium battery's lithium plating capacity.

[0077] Figure 6 A block diagram of a lithium plating prediction apparatus according to some embodiments of the present disclosure is shown. Figure 6 As shown, the lithium plating prediction device 600 includes a data acquisition module 602, configured to acquire a set of charging parameters for the lithium battery under a calibrated rate parameter and a target rate parameter. The charging parameter set includes multiple subsets of charging parameters, each subset including a thickness change value and at least one of the calibrated battery capacity under the calibrated rate parameter and the target battery capacity under the target rate parameter. The lithium plating prediction device 600 also includes a thickness calculation module 604, configured to determine the thickness change difference of the lithium battery under a specified charge amount based on the charging parameter set. The lithium plating prediction device 600 further includes a lithium plating calculation module 606, configured to obtain a calibrated differential parameter set and a target differential parameter set based on the charging parameter set, and to determine the lithium plating capacity of the lithium battery under a specified charge amount based on the calibrated differential parameter set and the target differential parameter set. In addition, the lithium plating prediction device 600 also includes a formula construction module 608, which is configured to determine the lithium plating capacity expression of the lithium battery at a target rate parameter based on a set of charging parameters, the thickness change difference of the lithium battery at a specified charge, and the lithium plating capacity.

[0078] Figure 7 Block diagrams of electronic devices that can implement various embodiments of the present disclosure are shown. For example... Figure 7 As shown, the electronic device 700 includes a processor 701, which can perform various appropriate actions and processes based on computer program instructions loaded into random access memory (RAM) 703 according to computer program instructions stored in read-only memory (ROM) 702. The RAM 703 may also store various programs and data required for the operation of the electronic device 700. The processor 701, ROM 702, and RAM 703 are interconnected via a bus 704. An input / output (I / O) interface 705 is also connected to the bus 704.

[0079] The various processes and procedures described above, such as method 200, can be executed by processor 701. For example, in some embodiments, method 200 may be implemented as a software program tangibly contained in a machine-readable medium. In some embodiments, part or all of the software program may be loaded into and / or installed onto electronic device 700 via ROM 702. When the software program is loaded into RAM 703 and executed by processor 701, one or more actions of method 200 described above may be performed.

[0080] The functions described above in this document can be performed at least in part by one or more hardware logic components. For example, exemplary types of hardware logic components that can be used, without limitation, include: field programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), payload programmable logic devices (CPLDs), and so on.

[0081] The program code used to implement the methods of this disclosure may be written in any combination of one or more programming languages. This program code may be provided to a processor or controller of a general-purpose computer, special-purpose computer, or other programmable data processing apparatus, such that when executed by the processor or controller, the program code causes the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code may be executed entirely on a machine, partially on a machine, as a standalone software package partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0082] This disclosure can be a method, apparatus, system, and / or program product. The program product may include a machine-readable storage medium on which machine-readable program instructions for performing various aspects of this disclosure are loaded. The machine-readable program instructions described herein can be downloaded from the machine-readable storage medium to various computing / processing devices, or downloaded via a network, such as the Internet, a local area network, a wide area network, and / or a wireless network, to an external computer or external storage device. The network may include copper transmission cables, fiber optic transmissions, wireless transmissions, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the machine-readable program instructions from the network and forwards them to the machine-readable storage medium in the respective computing / processing device.

[0083] Machine program instructions used to perform the operations of this disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, etc., and conventional procedural programming languages ​​such as the "C" language or similar programming languages. Machine-readable program instructions may be executed entirely on a user's computer, partially on a user's computer, as a standalone software package, partially on a user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuitry, such as programmable logic circuitry, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), is personalized by utilizing state information from the machine-readable program instructions. This electronic circuitry can execute the machine-readable program instructions to implement various aspects of this disclosure.

[0084] In the context of this disclosure, a machine-readable medium can be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, apparatus, or device. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. Machine-readable media can be, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing. Furthermore, although operations are depicted in a specific order, this should be understood as requiring that such operations be performed in the specific order shown or in sequential order, or requiring that all illustrated operations be performed to achieve the desired result. In certain environments, multitasking and parallel processing may be advantageous. Similarly, while several specific implementation details are included in the foregoing discussion, these should not be construed as limiting the scope of this disclosure. Certain features described in the context of individual embodiments may also be implemented in combination in a single implementation. Conversely, various features described in the context of a single implementation may also be implemented individually or in any suitable sub-combination in multiple implementations.

[0085] Although the subject matter has been described using language specific to structural features and / or methodological logic, it should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or actions described above. Rather, the specific features and actions described above are merely illustrative examples of implementing the claims.

Claims

1. A lithium precipitation prediction method characterized by, include: Obtain a set of charging parameters for a lithium battery under a calibrated rate parameter and a target rate parameter. The set of charging parameters includes multiple subsets of charging parameters, each subset of charging parameters including a thickness variation value and at least one of the calibrated battery capacity of the lithium battery under the calibrated rate parameter and the target battery capacity of the lithium battery under the target rate parameter. Based on the charging parameter set, the thickness change difference of the lithium battery under a specified charge is determined; Based on the charging parameter set, a calibration differential parameter set and a target differential parameter set are obtained, and based on the calibration differential parameter set and the target differential parameter set, the lithium plating capacity of the lithium battery at the specified charge is determined; the calibration differential parameter set includes the calibration battery capacity of each lithium battery at the calibration rate parameter, arranged in ascending order, and the calibration thickness change differential value corresponding to the calibration battery capacity of each lithium battery at the calibration rate parameter; the target differential parameter set includes the target battery capacity of each lithium battery at the target rate parameter, arranged in ascending order, and the target thickness change differential value corresponding to the target battery capacity of each lithium battery at the target rate parameter; as well as Based on the charging parameter set, the thickness change difference of the lithium battery under the specified charge, and the lithium plating capacity, the expression for the lithium battery's lithium plating capacity under the target rate parameter is determined. This also includes: Based on the calibrated battery capacity and the target battery capacity corresponding to the specified charge, the lithium plating capacity difference of the lithium battery under the specified charge is determined; The graphite expansion rate of the lithium battery is determined based on the maximum value of the rated battery capacity of all the lithium batteries under the rated rate parameter and the maximum value of the thickness change of all the lithium batteries under the rated rate parameter. Substituting the graphite expansion rate of the lithium battery, the thickness change difference of the lithium battery under the specified charge, the lithium plating capacity, and the lithium plating capacity difference into a preset lithium plating capacity expression, the parameters to be solved in the preset lithium plating capacity expression are calculated; and Based on the preset lithium plating capacity expression and the parameters to be solved in the preset lithium plating capacity expression, the lithium plating capacity expression of the lithium battery under the target rate parameter is determined. The preset lithium plating capacity expression is: ， In the above formula, Let A be the thickness variation difference of the lithium battery under a specified charge, and let A be the parameter to be solved. The graphite expansion rate of a lithium battery. This refers to the lithium plating capacity of a lithium battery at a specified charge level. This represents the lithium plating capacity difference of a lithium battery at a specified charge level.

2. The method of claim 1, wherein, The step of determining the thickness variation difference of the lithium battery under a specified charge amount based on the charging parameter set includes: Based on the calibrated battery capacity of the lithium battery in each of the charging parameter subsets under the calibrated rate parameter, and the maximum value of the calibrated battery capacity of all the lithium batteries under the calibrated rate parameter, the calibrated charge corresponding to each of the charging parameter subsets is determined; Based on the target battery capacity of the lithium batteries in each of the charging parameter subsets under the target rate parameter, and the maximum value among the target battery capacities of all lithium batteries under the target rate parameter, the target charge corresponding to each of the charging parameter subsets is determined; and Based on the thickness change value in each of the charging parameter subsets, the calibrated charge and the target charge corresponding to each of the charging parameter subsets, the thickness change difference of the lithium battery under a specified charge is determined, wherein the specified charge is consistent with any of the calibrated charge and any of the target charge.

3. The method of claim 1, wherein, The process of obtaining the calibration differential parameter set and the target differential parameter set based on the charging parameter set includes: Based on the thickness change value in each of the charging parameter subsets and the calibrated battery capacity of the lithium battery under the calibrated rate parameter, determine the calibrated thickness change differential value corresponding to the calibrated battery capacity of each lithium battery under the calibrated rate parameter; Based on the calibrated battery capacity of each lithium battery under the calibrated rate parameter, and the differential value of the calibrated thickness change corresponding to the calibrated battery capacity of each lithium battery under the calibrated rate parameter, a set of calibrated differential parameters is obtained; Based on the thickness change values ​​in each of the charging parameter subsets and the target battery capacity of the lithium battery at the target rate parameter, determine the differential value of the target thickness change corresponding to the target battery capacity of each lithium battery at the target rate parameter; and Based on the target battery capacity of each lithium battery under the target rate parameter, and the differential value of the target thickness change corresponding to the target battery capacity of each lithium battery under the target rate parameter, a target differential parameter set is obtained.

4. The method of claim 3, wherein, Determining the lithium plating capacity of the lithium battery at the specified charge level based on the calibrated differential parameter set and the target differential parameter set includes: The maximum value among all the differential values ​​of the calibration thickness variation is determined based on the calibration differential parameter set; The target battery capacity corresponding to the maximum value among all the differential values ​​of the calibrated thickness change in the target differential parameter set is determined as the first battery capacity; and The target battery capacity corresponding to the specified charge amount is determined as the second battery capacity, and the lithium plating capacity of the lithium battery under the specified charge amount is determined based on the second battery capacity and the first battery capacity.

5. The method of claim 1, wherein, The method further includes: Based on the target charge, determine the thickness variation difference and lithium plating capacity difference of the lithium battery at the target charge. Substituting the thickness variation difference and the lithium plating capacity difference of the lithium battery under the target charge into the lithium plating capacity expression of the lithium battery under the target rate parameter, the lithium plating capacity of the lithium battery under the target rate parameter and the target charge is obtained.

6. A lithium precipitation prediction device characterized by comprising: The apparatus is used to perform the lithium plating prediction method as described in any one of claims 1-5, the apparatus comprising: The data acquisition module is configured to acquire a set of charging parameters for the lithium battery under a calibrated rate parameter and a target rate parameter. The set of charging parameters includes multiple subsets of charging parameters, each subset of charging parameters including a thickness variation value and at least one of the calibrated battery capacity of the lithium battery under the calibrated rate parameter and the target battery capacity of the lithium battery under the target rate parameter. The thickness calculation module is configured to determine the thickness change difference of the lithium battery under a specified charge amount based on the charging parameter set. A lithium plating calculation module is configured to obtain a calibration differential parameter set and a target differential parameter set based on the charging parameter set, and to determine the lithium plating capacity of the lithium battery at the specified charge level based on the calibration differential parameter set and the target differential parameter set; and The formula construction module is configured to determine the lithium plating capacity expression of the lithium battery under the target rate parameter based on the charging parameter set, the thickness change difference of the lithium battery under the specified charge, and the lithium plating capacity.

7. A computer-readable storage medium having a computer program stored thereon, the computer-readable storage medium storing instructions that, when executed on a computer or processor, cause the computer or processor to perform the steps of the method as claimed in any one of claims 1-5.

8. An electronic device, comprising: include: One or more processors, and A memory associated with the one or more processors, the memory being used to store program instructions that, when read and executed by the one or more processors, perform the steps of the method according to any one of claims 1-5.

Images