Lithium battery pole piece resistance determination method and device and electronic equipment

Abstract

The embodiment of the invention discloses a lithium battery pole piece resistance determination method and device and electronic equipment. The method comprises the following steps: constructing a diaphragm resistance calculation equation of the lithium battery according to a test pole piece resistance calculation equation and a test contact resistance calculation equation, and determining the target pole piece resistance of the lithium battery based on multiple groups of historical test data and the diaphragm resistance calculation equation. Through the above steps, the directly tested diaphragm resistance is decomposed into the test pole piece resistance and the test contact resistance, fitting is performed on the diaphragm resistance calculation equation through multiple groups of historical test data, and the target pole piece resistance is determined according to the fitted equation model parameters. And the corresponding initial contact resistance when the stress of the test pole piece is zero can be determined, so that the test contact resistance which is difficult to determine is eliminated from the determined target pole piece resistance, the accuracy of the pole piece resistance result is improved, and the conductivity of the battery pole piece can be accurately evaluated subsequently.

Description

Technical Field

[0001] One or more embodiments of this specification relate to the technical field of battery resistance testing, and particularly to a method, device, and electronic device for determining the resistance of lithium battery electrode sheets. Background Art

[0002] The essence and composition of the internal resistance of lithium-ion batteries are related to the materials and designs of various components inside the battery cells. Generally, it is jointly determined by the electrode sheet resistance of the electrode sheet material and the lithium ion transfer resistance. The electrode sheet resistance of lithium batteries not only affects the power performance of the battery cells but also generates excessive Joule heat, causing the internal temperature of the battery cells to rise. Therefore, it is necessary to determine the electrode sheet resistance of lithium batteries to accurately evaluate the conductivity of the battery electrodes. The currently commonly used direct resistance measurement method has large data deviation in the final electrode sheet resistance approximated by the measured test resistance because the measured test resistance includes not only the electrode sheet resistance but also the contact resistance generated between the foil and the active material that cannot be tested. Moreover, the repeatability of secondary testing is poor, and accurate electrode sheet resistance cannot be obtained, affecting the subsequent evaluation of the conductivity of battery electrodes. Summary of the Invention

[0003] Embodiments of this specification provide a method, device, and electronic device for determining the resistance of lithium battery electrode sheets. The technical solutions are as follows: In a first aspect, embodiments of this specification provide a method for determining the resistance of lithium battery electrode sheets. The method includes: Construct a diaphragm resistance calculation equation for the lithium battery according to a test electrode sheet resistance calculation equation and a test contact resistance calculation equation. The test electrode sheet resistance calculation equation is used to calculate the test electrode sheet resistance according to the test electrode sheet strain during the test process of the lithium battery, and the test contact resistance calculation equation is used to calculate the test contact resistance according to the test electrode sheet stress during the test process of the lithium battery; Determine the target electrode sheet resistance of the lithium battery based on at least two sets of historical test data and the diaphragm resistance calculation equation. The historical test data includes historical test diaphragm resistance and the test electrode sheet stress corresponding to the historical test time. The target electrode sheet resistance is used to characterize the electrode sheet resistance when the test electrode sheet stress is zero.

[0004] In a second aspect, a device for determining the resistance of lithium battery electrode sheets is provided. The device includes: A construction module for constructing a diaphragm resistance calculation equation for the lithium battery according to a test electrode sheet resistance calculation equation and a test contact resistance calculation equation. The test electrode sheet resistance calculation equation is used to calculate the test electrode sheet resistance according to the test electrode sheet strain during the test process of the lithium battery, and the test contact resistance calculation equation is used to calculate the test contact resistance according to the test electrode sheet stress during the test process of the lithium battery; A determination module, configured to determine a target pole piece resistance of the lithium battery based on at least two sets of historical test data and the diaphragm resistance calculation equation, where the historical test data includes historical test diaphragm resistance and the test pole piece stress corresponding to the historical test moment, and the target pole piece resistance is used to characterize the pole piece resistance when the test pole piece stress is zero.

[0005] In a third aspect, an electronic device is provided, including a device processor and a memory; The device processor is connected to the memory; The memory is used to store executable program code; The device processor runs a program corresponding to the executable program code by reading the executable program code stored in the memory, so as to execute the steps of the method provided in the first aspect or any one of the possible implementation manners of the first aspect.

[0006] In a fourth aspect, a computer-readable storage medium is provided, on which a computer program is stored. Instructions are stored in the computer-readable storage medium. When the instructions are run on a computer or a device processor, the computer or the device processor is caused to execute the method provided in the first aspect or any one of the possible implementation manners of the first aspect.

[0007] The beneficial effects brought by the technical solutions provided in some embodiments of this specification at least include: In one or more embodiments of this specification, a diaphragm resistance calculation equation of the lithium battery can be constructed according to the test pole piece resistance calculation equation and the test contact resistance calculation equation, and then the target pole piece resistance of the lithium battery is determined based on multiple sets of historical test data and the diaphragm resistance calculation equation. Through the above steps, the directly testable diaphragm resistance is decomposed into the test pole piece resistance and the test contact resistance, and the diaphragm resistance calculation equation is fitted with multiple sets of historical test data. The target pole piece resistance is determined according to the fitted equation model parameters, and the initial contact resistance corresponding to when the test pole piece stress is zero can also be determined, so that the determined target pole piece resistance excludes the difficult-to-determine test contact resistance, improves the accuracy of the pole piece resistance result, and facilitates the accurate evaluation of the conductivity of the battery pole piece in the future. Description of the Drawings

[0008] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0009] Figure 1Flow chart of a method for determining the resistance of a lithium battery electrode sheet provided in an embodiment of this specification; Figure 2 Structural schematic diagram of a device for determining the resistance of a lithium battery electrode sheet provided in an embodiment of this specification; Figure 3 Structural schematic diagram of an electronic device provided in an embodiment of this specification. Specific embodiments

[0010] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application.

[0011] The terms "first", "second", "third", etc. in the specification, claims and the above drawings of this specification are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally further includes steps or units not listed, or optionally further includes other steps or units inherent to these processes, methods, products or devices.

[0012] The following description provides examples and does not limit the scope, applicability or examples set forth in the claims. Changes can be made to the functions and arrangements of the described elements without departing from the scope of the content of this specification. Each example may appropriately omit, substitute or add various processes or components. For example, the described method may be executed in a different order from the described order, and various steps may be added, omitted or combined. In addition, the features described in some examples can be combined into other examples.

[0013] Please refer to Figure 1 , Figure 1 which shows the overall flow chart of a method for determining the resistance of a lithium battery electrode sheet provided in an embodiment of this specification.

[0014] As Figure 1 shown, the method for determining the resistance of the lithium battery electrode sheet may at least include the following steps: Step 101, construct a diaphragm resistance calculation equation of the lithium battery according to the test electrode sheet resistance calculation equation and the test contact resistance calculation equation.

[0015] Among them, the test electrode sheet resistance calculation equation is used to calculate the test electrode sheet resistance according to the test electrode sheet strain during the test of the lithium battery, and the test contact resistance calculation equation is used to calculate the test contact resistance according to the test electrode sheet stress during the test of the lithium battery.

[0016] In the embodiments of this specification, when testing the pole piece resistance of a lithium battery, a diaphragm tester is used. Since the measured diaphragm resistance includes not only the test pole piece resistance composed of the active material of the lithium battery pole piece itself, but also the test contact resistance between the tester foil and the active material. Among them, in the actual testing process, the diaphragm resistances of the positive and negative poles of the lithium battery are composed of the true positive and negative pole piece resistances and the contact resistance in series on both sides. And the positive and negative pole pieces are porous structures, resulting in the test pole piece resistance changing with the change of the test pole piece strain amount during the testing process of the lithium battery, and the test contact resistance changing with the change of the test pole piece stress during the testing process of the lithium battery. However, the target lithium battery pole piece resistance to be determined in the present invention is the initial pole piece resistance corresponding to when the pole piece resistance is not subjected to the test pole piece stress, that is, when the test pole piece stress is zero, but the target lithium battery pole piece resistance cannot be directly obtained. Therefore, it is necessary to first determine the test pole piece resistance calculation equation and the test contact resistance calculation equation corresponding to the lithium battery during the testing process.

[0017] Among them, the test pole piece resistance calculation equation can be determined by the target pole piece resistance and the pole piece strain amount, and the test contact resistance can be determined by the fixed contact parameter and the test pole piece stress. Then, the test pole piece resistance calculation equation and the test contact resistance calculation equation are sorted out and combined or the equation model is converted to construct the diaphragm resistance calculation equation of the lithium battery. So as to subsequently deduce the constructed diaphragm resistance calculation equation through multiple groups of historical test data to determine the target lithium battery pole piece resistance to be determined therein.

[0018] In an implementable manner, the constructing the diaphragm resistance calculation equation of the lithium battery according to the test pole piece resistance calculation equation and the test contact resistance calculation equation includes: Constructing a test pole piece resistance calculation equation based on the test pole piece strain amount, and constructing a test contact resistance calculation equation based on the test pole piece stress; Combining the test pole piece resistance calculation equation and the test contact resistance calculation equation to obtain the diaphragm resistance calculation equation of the lithium battery.

[0019] In the embodiments of this specification, when constructing the diaphragm resistance calculation equation of a lithium battery, the test electrode sheet resistance calculation equation can be constructed first according to the target electrode sheet resistance and the strain of the electrode sheet, and then the test contact resistance calculation equation can be constructed according to the fixed contact parameters between the diaphragm resistance probe and the test electrode sheet and the stress of the test electrode sheet. Among them, when constructing the test electrode sheet resistance calculation equation and the test contact resistance calculation equation, conventional mathematical models such as linear, polynomial, exponential, or neural network models can be used for modeling. Further, since the diaphragm resistance probe measures the positive electrode sheet and the negative electrode sheet in series with the diaphragm resistance probe during the diaphragm resistance test, the measured diaphragm resistance will include two sets of test electrode sheet resistances and test contact resistances. Therefore, the constructed test electrode sheet resistance calculation equation and test contact resistance calculation equation can be added and combined on both sides of the equal sign and then doubled to obtain the diaphragm resistance calculation equation of the lithium battery.

[0020] Among them, if the test electrode sheet resistance calculation equation is the test electrode sheet resistance , and the test contact resistance calculation equation is the test contact resistance , then the diaphragm resistance calculation equation is the diaphragm resistance .

[0021] In an implementable manner, constructing the test electrode sheet resistance calculation equation based on the strain of the test electrode sheet includes: Performing a multiplication process on the initial preset electrode sheet resistance and the strain of the test electrode sheet to obtain the first calculation data; Based on the difference calculation data obtained by processing the difference between the initial electrode sheet resistance and the first calculation data, a test electrode sheet resistance calculation equation is constructed.

[0022] In the embodiments of this specification, when constructing the test electrode sheet resistance calculation equation, the initial preset electrode sheet resistance can be set first, which is used to represent the target lithium battery electrode sheet resistance to be determined when the electrode sheet resistance is not subjected to the stress of the test electrode sheet, that is, the strain of the test electrode sheet is zero. Then, the initial preset electrode sheet resistance is multiplied by the strain of the test electrode sheet to obtain the first calculation data . Then, the difference between the initial electrode sheet resistance and the first calculation data is calculated to obtain the difference calculation data . Finally, according to the difference calculation data , the test electrode sheet resistance calculation equation is constructed as follows: Among them, is the test electrode sheet resistance, is the strain of the test electrode sheet, is the electrode sheet resistance without strain, and are both preset parameters to be determined.

[0023] In an implementable manner, constructing the test contact resistance calculation equation based on the stress of the test electrode includes: Performing a power processing on the first preset contact parameter and the stress of the test electrode to obtain a second calculation data; Constructing a test contact resistance calculation equation based on the ratio calculation data obtained by processing the second preset contact parameter and the second calculation data, where the first preset contact parameter is the stress characteristic parameter corresponding to the contact surface between the diaphragm resistance probe and the test electrode, and the second preset contact parameter is the friction characteristic parameter corresponding to the contact surface.

[0024] In the embodiments of this specification, when constructing the test contact resistance calculation equation, the stress characteristic parameter corresponding to the contact surface between the diaphragm resistance probe and the test electrode, that is, the first preset contact parameter m, and the friction characteristic parameter corresponding to the contact surface, that is, the second preset contact parameter K, can be set first. Then, the first preset contact parameter m is subjected to power processing with the test contact force F to obtain a second calculation data . Further, the second preset contact parameter K and the second calculation data are processed to perform a ratio calculation to obtain ratio calculation data . Finally, according to the ratio calculation data construct the test contact resistance calculation equation as follows: Among them, is the test contact resistance, m is the first preset contact parameter, K is the second preset contact parameter, and F is the test contact force. Both m and K are preset parameters to be determined.

[0025] Further, in the actual compression quasi-static process, the test contact force F can be equivalent to the stress σ of the test electrode of the porous material. Therefore, the above test contact resistance calculation equation can be changed as follows: Among them, σ is the stress of the test electrode, is the electrode stress compensation parameter to be determined.

[0026] In summary, the finally combined diaphragm resistance calculation equation is: Step 102: Determine the target electrode resistance of the lithium battery based on at least two groups of historical test data and the diaphragm resistance calculation equation.

[0027] Among them, the historical test data includes the historical test diaphragm resistance and the stress of the test pole piece corresponding to the historical test time, and the target pole piece resistance is used to characterize the pole piece resistance when the stress of the test pole piece is zero.

[0028] In the embodiments of this specification, after constructing the calculation equation of the diaphragm resistance of the lithium battery, multiple groups of historical test data obtained can be used to fit the calculation equation of the diaphragm resistance or train the model, and the target pole piece resistance in the calculation equation of the diaphragm resistance can be determined according to the fitting result or the result of the trained model.

[0029] As an example, if the calculation equation of the diaphragm resistance is: Then the finally determined initial preset pole piece resistance is the target pole piece resistance corresponding to when the stress of the test pole piece is zero. Among them, the historical test data includes the historical test diaphragm resistance and the stress of the test pole piece corresponding to the historical test time. When obtaining each group of historical test data, the force of the probe pressing down can be set respectively under the diaphragm resistance instrument, and a pressure σ of 10 MPa to 100 MPa can be applied in sequence from small to large every 5 MPa, and the historical test diaphragm resistance R corresponding to each group of tests and the corresponding stress σ of the test pole piece can be obtained.

[0030] In an implementable manner, the method further includes: Constructing a non-linear change model between the stress of the test pole piece and the strain of the test pole piece; Training the non-linear change model based on the historical stress-strain data set to obtain a trained non-linear change model.

[0031] In the embodiments of this specification, since in the actual diaphragm resistance test process, the stress of the test pole piece can be directly retrieved from the setting of the downward pressure of the test probe, but the calculation equation of the test pole piece resistance requires the strain of the test pole piece, and the strain of the test pole piece is often too small during each test, and the measurement process by the instrument is cumbersome and prone to measurement errors each time. Therefore, a non-linear change model between the stress of the test pole piece and the strain of the test pole piece can be constructed first. Then, only a limited and pre-tested historical stress-strain data set is needed to train the non-linear change model to obtain a trained non-linear change model. Subsequently, when it is necessary to determine the strain of the test pole piece to construct the calculation equation of the test pole piece resistance, only the stress of the test pole piece needs to be determined first, and then the corresponding strain of the test pole piece can be obtained through the trained non-linear change model.

[0032] Optionally, the non-linear change model can be set as follows: Among them, σ is the stress of the test pole piece, is the strain of the test electrode, is the maximum Young's model, and β is a parameter representing the rate of increase of Young's modulus. is the ultimate strain of the compression of the porous electrode material, which can be approximately equal to the porosity. and β can be obtained by fitting the historical stress-strain data set.

[0033] In an implementable manner, determining the target electrode resistance of the lithium battery based on at least two sets of historical test data and the diaphragm resistance calculation equation includes: Determining the strain of the test electrode corresponding to the stress of the test electrode in the historical test data based on the trained non-linear change model; Fitting the diaphragm resistance calculation equation according to each of the historical test diaphragm resistances, the strain of the test electrode, and the stress of the test electrode corresponding to each historical test time to obtain a fitting equation; Determining the target electrode resistance of the lithium battery based on the fitting parameters in the fitting equation.

[0034] In the embodiments of this specification, the stress of the test electrode in the historical test data can be first input into the trained non-linear change model to determine the corresponding strain of the test electrode. Then, the diaphragm resistance calculation equation is fitted multiple times with each historical test diaphragm resistance, the strain of the test electrode, and the stress of the test electrode corresponding to each historical test time. Among them, a genetic algorithm or a neural network algorithm can be used for fitting to obtain a fitting equation. Finally, according to the fitting parameters in the fitting equation the target electrode resistance of the lithium battery can be determined. Among them, in addition to determining the target electrode resistance of the lithium battery, the initial contact resistance corresponding to when the stress of the test electrode is zero can also be determined through the fitting parameters in the fitting equation

[0035] In an implementable manner, fitting the diaphragm resistance calculation equation according to each of the historical test diaphragm resistances, the strain of the test electrode, and the stress of the test electrode corresponding to each historical test time to obtain a fitting equation includes: Determining the initial parameter population corresponding to the diaphragm resistance calculation equation based on a genetic algorithm; Iterating the initial parameter population to determine the target iteration parameter corresponding to when the resistance difference between the calculated diaphragm resistance and the historical test diaphragm resistance meets a preset requirement, where the calculated diaphragm resistance is the diaphragm resistance calculated according to the diaphragm resistance calculation equation for the strain of the test electrode and the stress of the test electrode; Fitting the diaphragm resistance calculation equation according to each of the target iteration parameters to obtain a fitting equation. ​

[0036] In the embodiments of this specification, the parameter ranges of the fitting parameters to be determined in the diaphragm resistance calculation equation can be determined first, and then the random method is used to generate an initial parameter population within the determined parameter range space. Each individual represents a set of possible parameter values. Then, the parameters are converted into a coding form that can be operated by the genetic algorithm, usually using binary coding, and the initialized parameter population is continuously iterated until the resistance difference between the calculated diaphragm resistance and the historical tested diaphragm resistance meets the preset requirements, that is, when the resistance difference is less than the preset resistance difference threshold, the iteration is stopped and the target iteration parameters corresponding to the parameter population at this time are determined. Further, according to the determined target iteration parameters, the fitting parameters in the diaphragm resistance calculation equation at this time are determined to obtain the fitting equation.

[0037] The above describes specific embodiments of this specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims can be performed in a different order than in the embodiments and still achieve the desired results. Additionally, the processes depicted in the figures do not necessarily require the specific order or sequential order shown to achieve the desired results. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0038] Next, please refer to Figure 2 , Figure 3 which shows a schematic structural diagram of a lithium battery electrode sheet resistance determination device provided by an embodiment of this specification. It should be noted that Figure 2 the shown lithium battery electrode sheet resistance determination device is used to execute the method of the embodiment of this application Figure 1 For the sake of convenience of description, only the parts related to the embodiment of this application are shown. For the specific technical details not disclosed, please refer to the embodiment shown in this application Figure 1 .

[0039] As Figure 2 shown, the lithium battery electrode sheet resistance determination device can at least include: A construction module 201, configured to construct a diaphragm resistance calculation equation of the lithium battery according to a test electrode sheet resistance calculation equation and a test contact resistance calculation equation, where the test electrode sheet resistance calculation equation is used to calculate the test electrode sheet resistance according to the test electrode sheet strain during the test of the lithium battery, and the test contact resistance calculation equation is used to calculate the test contact resistance according to the test electrode sheet stress during the test of the lithium battery; A determination module 202 is configured to determine the target pole piece resistance of the lithium battery based on at least two sets of historical test data and the diaphragm resistance calculation equation. The historical test data includes the historical test diaphragm resistance and the test pole piece stress corresponding to the historical test moment. The target pole piece resistance is used to characterize the pole piece resistance when the test pole piece stress is zero.

[0040] In an implementable embodiment, the construction module 201 is specifically configured to: Construct a test pole piece resistance calculation equation based on the test pole piece strain, and construct a test contact resistance calculation equation based on the test pole piece stress; Combine the test pole piece resistance calculation equation and the test contact resistance calculation equation to obtain the diaphragm resistance calculation equation of the lithium battery.

[0041] In an implementable embodiment, the construction module 201 is further specifically configured to: Perform a multiplication process on the initial preset pole piece resistance and the test pole piece strain to obtain a first calculation data; Construct a test pole piece resistance calculation equation based on the difference calculation data obtained by processing the initial pole piece resistance and the first calculation data.

[0042] In an implementable embodiment, the construction module 201 is further specifically configured to: Perform a power process on the first preset contact parameter and the test pole piece stress to obtain a second calculation data; Construct a test contact resistance calculation equation based on the ratio calculation data obtained by processing the second preset contact parameter and the second calculation data. The first preset contact parameter is a stress characteristic parameter corresponding to the contact surface between the diaphragm resistance probe and the test pole piece, and the second preset contact parameter is a friction characteristic parameter corresponding to the contact surface.

[0043] In an implementable embodiment, the construction module 202 is specifically configured to: Construct a non-linear change model between the test pole piece stress and the test pole piece strain; Train the non-linear change model based on the historical stress-strain data set to obtain a trained non-linear change model.

[0044] In an implementable embodiment, the construction module 202 is further specifically configured to: Determine the test pole piece strain corresponding to the test pole piece stress in the historical test data based on the trained non-linear change model; Fit the diaphragm resistance calculation equation according to each historical test diaphragm resistance, the test pole piece strain and the test pole piece stress corresponding to each historical test moment to obtain a fitting equation; Determine the target pole piece resistance of the lithium battery based on the fitting parameters in the fitting equation.

[0045] In an implementable manner, the construction module 202 is further specifically configured to: Determine an initial parameter population corresponding to the diaphragm resistance calculation equation based on a genetic algorithm; Iterate the initial parameter population, and determine the target iteration parameter corresponding to when the resistance difference between the calculated diaphragm resistance and the historical test diaphragm resistance meets a preset requirement, where the calculated diaphragm resistance is the diaphragm resistance calculated according to the diaphragm resistance calculation equation for the strain of the test pole piece and the stress of the test pole piece; Fit the diaphragm resistance calculation equation according to each of the target iteration parameters to obtain a fitting equation.

[0046] Those skilled in the art can clearly understand that the technical solutions of the embodiments of the present application can be implemented by means of software and / or hardware. The "units" and "modules" in this specification refer to software and / or hardware that can independently complete or cooperate with other components to complete specific functions, where the hardware can be, for example, a Field-Programmable Gate Array (FPGA), an Integrated Circuit (IC), etc.

[0047] Each processing unit and / or module of the embodiments of the present application can be implemented by an analog circuit that implements the functions described in the embodiments of the present application, or can be implemented by software that executes the functions described in the embodiments of the present application.

[0048] As Figure 3 shown, the electronic device 300 may include: at least one device processor 301, at least one network interface 303, a user interface 303, a memory 305, and at least one communication bus 302.

[0049] Among them, the communication bus 302 can be used to realize the connection and communication of the above-mentioned various components.

[0050] Among them, the user interface 303 may include buttons, and the optional user interface may further include a standard wired interface and a wireless interface.

[0051] Among them, the network interface 304 may include, but is not limited to, a Bluetooth module, an NFC module, a Wi-Fi module, etc.

[0052] Among them, the device processor 301 may include one or more processing cores. The device processor 301 connects various parts within the entire electronic device 300 through various interfaces and circuits. By running or executing instructions, programs, code sets, or instruction sets stored in the memory 305, and by calling the data stored in the memory 305, it executes various functions of the electronic device 300 and processes data. Optionally, the device processor 301 may be implemented in at least one hardware form of DSP, FPGA, or PLA. The device processor 301 may integrate one or a combination of several of CPU, GPU, and modem, etc. Among them, the CPU mainly processes the operating system, user interface, application programs, etc.; the GPU is responsible for rendering and drawing the content to be displayed on the display screen; the modem is used to process wireless communication. It can be understood that the above modem may not be integrated into the device processor 301 and may be implemented separately by a single chip.

[0053] Among them, the memory 305 may include RAM and may also include ROM. Optionally, the memory 305 includes a non-transitory computer-readable medium. The memory 305 can be used to store instructions, programs, code, code sets, or instruction sets. The memory 305 may include a program storage area and a data storage area. Among them, the program storage area may store instructions for implementing the operating system, instructions for at least one function (such as touch function, sound playback function, image playback function, etc.), instructions for implementing the above-mentioned method embodiments, etc.; the data storage area may store the data involved in the above-mentioned method embodiments. Optionally, the memory 305 may also be at least one storage device located far from the aforementioned device processor 301. As Figure 3 shown, the memory 305, as a computer storage medium, may include an operating system, a network communication module, a user interface module, and program instructions.

[0054] Specifically, the device processor 301 can be used to call the temperature control application program of the battery pack system stored in the memory 305 and specifically perform the following operations: Construct a diaphragm resistance calculation equation of the lithium battery according to the test pole piece resistance calculation equation and the test contact resistance calculation equation. The test pole piece resistance calculation equation is used to calculate the test pole piece resistance according to the test pole piece strain of the lithium battery during the test process, and the test contact resistance calculation equation is used to calculate the test contact resistance according to the test pole piece stress of the lithium battery during the test process; Determine the target pole piece resistance of the lithium battery based on at least two sets of historical test data and the diaphragm resistance calculation equation. The historical test data includes historical test diaphragm resistance and the test pole piece stress corresponding to the historical test moment. The target pole piece resistance is used to characterize the pole piece resistance when the test pole piece stress is zero.

[0055] As an option in the embodiments of this specification, constructing the diaphragm resistance calculation equation of the lithium battery according to the test pole piece resistance calculation equation and the test contact resistance calculation equation includes: Constructing a test pole piece resistance calculation equation based on the test pole piece strain and constructing a test contact resistance calculation equation based on the test pole piece stress; Combining the test pole piece resistance calculation equation and the test contact resistance calculation equation to obtain the diaphragm resistance calculation equation of the lithium battery.

[0056] As an option in the embodiments of this specification, constructing the test pole piece resistance calculation equation based on the test pole piece strain includes: Performing a multiplication process on the initial preset pole piece resistance and the test pole piece strain to obtain first calculation data; Constructing a test pole piece resistance calculation equation based on the difference calculation data obtained by processing the initial pole piece resistance and the first calculation data.

[0057] As an option in the embodiments of this specification, constructing the test contact resistance calculation equation based on the test pole piece stress includes: Performing a power process on the first preset contact parameter and the test pole piece stress to obtain second calculation data; Constructing a test contact resistance calculation equation based on the ratio calculation data obtained by processing the second preset contact parameter and the second calculation data, where the first preset contact parameter is the stress characteristic parameter corresponding to the contact surface between the diaphragm resistance probe and the test pole piece, and the second preset contact parameter is the friction characteristic parameter corresponding to the contact surface.

[0058] As an option in the embodiments of this specification, the method further includes: Constructing a non-linear change model between the test pole piece stress and the test pole piece strain; Training the non-linear change model based on the historical stress-strain data set to obtain a trained non-linear change model.

[0059] As an option in the embodiments of this specification, determining the target pole piece resistance of the lithium battery based on at least two groups of historical test data and the diaphragm resistance calculation equation includes: Determining the test pole piece strain corresponding to the test pole piece stress in the historical test data based on the trained non-linear change model; Fitting the diaphragm resistance calculation equation according to each historical test diaphragm resistance and the test pole piece strain and the test pole piece stress corresponding to each historical test moment to obtain a fitting equation; Determining the target pole piece resistance of the lithium battery based on the fitting parameters in the fitting equation.

[0060] As an option of the embodiment of this specification, fitting the diaphragm resistance calculation equation according to each of the historical test diaphragm resistances, the strain of the test pole piece and the stress of the test pole piece corresponding to each historical test time to obtain a fitting equation includes: Determine an initial parameter population corresponding to the diaphragm resistance calculation equation based on a genetic algorithm; Iterate the initial parameter population to determine target iteration parameters corresponding to when the resistance difference between the calculated diaphragm resistance and the historical test diaphragm resistance meets a preset requirement, where the calculated diaphragm resistance is the diaphragm resistance calculated according to the diaphragm resistance calculation equation for the strain of the test pole piece and the stress of the test pole piece; Fit the diaphragm resistance calculation equation according to each of the target iteration parameters to obtain a fitting equation.

[0061] The embodiment of this specification also provides a computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, the steps of the above method are implemented. Among them, the computer-readable storage medium may include, but is not limited to, any type of disk, including floppy disks, optical disks, DVDs, CD-ROMs, microdrives, and magneto-optical disks, ROMs, RAMs, EPROMs, EEPROMs, DRAMs, VRAMs, flash memory devices, magnetic cards or optical cards, nanosystems (including molecular memory ICs), or any type of medium or device suitable for storing instructions and / or data.

[0062] It should be noted that, for the foregoing method embodiments, for the sake of simple description, they are all expressed as a series of action combinations. However, those skilled in the art should know that this application is not limited by the described action sequence, because according to this application, certain steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0063] In the above embodiments, the descriptions of the various embodiments have their own emphases. For the parts not detailed in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0064] In several embodiments provided in the present application, it should be understood that the disclosed device can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the above-mentioned units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling or direct coupling or communication connection between each other can be through some service interfaces. The indirect coupling or communication connection of the device or unit can be in an electrical or other form.

[0065] The units described as separate components may or may not be physically separated. The components displayed as units may or may not be physical units, that is, they can be located in one place, or they can be distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0066] In addition, each functional unit in various embodiments of the present application can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

[0067] If the above-mentioned integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable memory. Based on such an understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a memory and includes several instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present application. And the aforementioned memory includes: USB flash drives, read-only memory (ROM), random access memory (RAM), mobile hard disks, magnetic disks, or optical discs and other media that can store program codes.

[0068] Those of ordinary skill in the art can understand that all or part of the steps in the various methods of the above embodiments can be completed by instructing relevant hardware through a program. This program can be stored in a computer-readable memory. The memory can include: flash drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical discs, etc.

[0069] The above describes specific embodiments of the present specification. Other embodiments are within the scope of the appended claims. In some cases, the acts or steps recited in the claims may be performed in a different order than in the embodiments and still achieve the desired result. Additionally, the processes depicted in the figures do not necessarily require the particular order shown or sequential order to achieve the desired result. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

Claims

1. A method for determining the resistance of a lithium battery electrode sheet, characterized in that, The method includes: Constructing a diaphragm resistance calculation equation of the lithium battery according to a test pole piece resistance calculation equation and a test contact resistance calculation equation, where the test pole piece resistance calculation equation is used to calculate the test pole piece resistance according to the test pole piece strain of the lithium battery during the test, and the test contact resistance calculation equation is used to calculate the test contact resistance according to the test pole piece stress of the lithium battery during the test; Determining the target pole piece resistance of the lithium battery based on at least two sets of historical test data and the diaphragm resistance calculation equation, where the historical test data includes the historical test diaphragm resistance and the test pole piece stress corresponding to the historical test moment, and the target pole piece resistance is used to characterize the pole piece resistance when the test pole piece stress is zero.

2. The method according to claim 1, wherein The constructing the diaphragm resistance calculation equation of the lithium battery according to the test pole piece resistance calculation equation and the test contact resistance calculation equation includes: Constructing a test pole piece resistance calculation equation based on the test pole piece strain and constructing a test contact resistance calculation equation based on the test pole piece stress; Combining the test pole piece resistance calculation equation and the test contact resistance calculation equation to obtain the diaphragm resistance calculation equation of the lithium battery.

3. The method according to claim 2, wherein The constructing the test pole piece resistance calculation equation based on the test pole piece strain includes: Performing a product process on the initial preset pole piece resistance and the test pole piece strain to obtain a first calculation data; Constructing a test pole piece resistance calculation equation based on the difference calculation data obtained by processing the initial preset pole piece resistance and the first calculation data.

4. The method according to claim 2, characterized in that, The constructing the test contact resistance calculation equation based on the test pole piece stress includes: Performing a power process on the first preset contact parameter and the test pole piece stress to obtain a second calculation data; Constructing a test contact resistance calculation equation based on the ratio calculation data obtained by processing the second preset contact parameter and the second calculation data, where the first preset contact parameter is a stress characteristic parameter corresponding to the contact surface between the diaphragm resistance probe and the test pole piece, and the second preset contact parameter is a friction characteristic parameter corresponding to the contact surface.

5. The method according to claim 1, wherein The method further includes: Constructing a non-linear change model between the test pole piece stress and the test pole piece strain; Training the non-linear change model based on a historical stress-strain data set to obtain a trained non-linear change model.

6. The method according to claim 5, wherein The determining the target pole piece resistance of the lithium battery based on at least two sets of historical test data and the diaphragm resistance calculation equation includes: Determining the test pole piece strain corresponding to the test pole piece stress in the historical test data based on the trained non-linear change model; Fitting the diaphragm resistance calculation equation according to each of the historical test diaphragm resistances, the test pole piece strain and the test pole piece stress corresponding to each historical test moment to obtain a fitting equation; Determining the target pole piece resistance of the lithium battery based on the fitting parameters in the fitting equation.

7. The method according to claim 6, wherein The fitting the diaphragm resistance calculation equation according to each of the historical test diaphragm resistances, the test pole piece strain and the test pole piece stress corresponding to each historical test moment to obtain a fitting equation includes: Determine the initial parameter population corresponding to the diaphragm resistance calculation equation based on the genetic algorithm; Iterate the initial parameter population to determine the target iteration parameters corresponding to when the resistance difference between the calculated diaphragm resistance and the historical tested diaphragm resistance meets the preset requirements. The calculated diaphragm resistance is the diaphragm resistance calculated according to the diaphragm resistance calculation equation for the strain of the tested pole piece and the stress of the tested pole piece; Fit the diaphragm resistance calculation equation according to each of the target iteration parameters to obtain a fitting equation.

8. A lithium battery electrode sheet resistance determination device, characterized in that, The device includes: A construction module for constructing a diaphragm resistance calculation equation of a lithium battery according to a tested pole piece resistance calculation equation and a tested contact resistance calculation equation. The tested pole piece resistance calculation equation is used to calculate the tested pole piece resistance according to the strain of the tested pole piece during the test of the lithium battery, and the tested contact resistance calculation equation is used to calculate the tested contact resistance according to the stress of the tested pole piece during the test of the lithium battery; A determination module for determining the target pole piece resistance of the lithium battery based on at least two groups of historical test data and the diaphragm resistance calculation equation. The historical test data includes the historical tested diaphragm resistance and the stress of the tested pole piece corresponding to the historical test time. The target pole piece resistance is used to characterize the pole piece resistance when the stress of the tested pole piece is zero.

9. An electronic device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the computer program, the steps of the method according to any one of claims 1-7 are implemented.

10. A computer-readable storage medium, on which a computer program is stored. The computer-readable storage medium stores instructions, and when the instructions run on a computer or a processor, the computer or the processor is caused to execute the steps of the method according to any one of claims 1-7.

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