Pole piece size determination method and device and storage medium

Abstract

The invention provides a pole piece size determination method and device and a storage medium, pole piece size parameters of a battery to be designed can be obtained, a corresponding electrochemical mechanism model is constructed, and the pole piece size parameters at least comprise the difference between the width of a positive pole piece and the width of a negative pole piece; inputting preset simulation working condition information to determine at least two charging standing relaxation voltages corresponding to the pole piece size parameters; judging the reasonability of the size parameters of the pole piece according to the two charging standing relaxation voltages; and if the two charging standing relaxation voltages are not reasonable, adjusting the size parameter of the pole piece until the size parameter of the pole piece is judged to be reasonable according to the two charging standing relaxation voltages corresponding to the adjusted size parameter of the pole piece. By applying the method provided by the embodiment of the invention, the pole piece size parameter can be continuously iteratively optimized according to the simulation result of the electrochemical mechanism model, the pole piece size parameter which finally meets the condition is obtained, and the optimal pole piece size parameter under the specific working condition can be accurately determined.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a method, device and storage medium for determining the size of a pole piece. Background Art

[0002] In the design and manufacturing process of lithium-ion batteries, the design of the overhang structure of the pole piece plays a vital role, aiming to curb the formation of lithium dendrites and ensure battery safety and performance stability. The formation of lithium dendrites, especially the uncontrollable deposition on the surface of the negative electrode, is one of the main causes of internal short circuits, thermal runaway and even safety accidents in batteries. To meet this challenge, engineers conventionally adopt the strategy of setting up an overhang area, intending to limit the excessive deposition of lithium ions at the edge of the pole piece, thereby avoiding the risk of lithium dendrites penetrating the diaphragm.

[0003] However, existing design methods face significant technical difficulties in determining the pole piece size parameters. First, the design parameters mostly rely on the engineer's accumulated experience and historical production data. This method is highly subjective and lacks systematic theoretical support. Due to the complex electrochemical behavior of lithium-ion batteries, especially the lateral diffusion of lithium ions during the charge and discharge cycle, it is difficult to accurately predict and quantify the direct impact of pole piece size parameters on the lithium dendrite inhibition effect based on experience alone. Therefore, in actual applications, the pole piece size parameters are often conservatively or insufficiently designed, which affects the energy density and cycle life of the battery.

[0004] Application Contents

[0005] The technical problem to be solved by this application is to provide a method, device and storage medium for determining the size of a pole piece, which can accurately determine the pole piece size parameters of a battery pole piece. The specific solution is as follows:

[0006] A method for determining the size of a pole piece, comprising:

[0007] Obtaining the electrode size parameters of the battery to be designed and constructing a corresponding electrochemical mechanism model, wherein the electrode size parameters at least include the difference between the width of the positive electrode and the width of the negative electrode;

[0008] Inputting preset simulation operating condition information to determine at least two charging static relaxation voltages corresponding to the pole piece size parameters;

[0009] Judging the rationality of the pole piece size parameters according to the two charging static relaxation voltages;

[0010] If it is unreasonable, the pole piece size parameter is adjusted until the pole piece size parameter is judged to be reasonable based on two charging static relaxation voltages corresponding to the adjusted pole piece size parameter.

[0011] In the above method, optionally, the step of judging the rationality of the pole piece size parameters according to the two charging static relaxation voltages comprises:

[0012] If the difference between the two charging static relaxation voltages is less than a preset threshold, the corresponding pole piece size parameters are judged to be reasonable; otherwise, they are judged to be unreasonable, wherein the two charging static relaxation voltages include a first charging static relaxation voltage and a second charging static relaxation voltage.

[0013] In the above method, optionally, the step of inputting preset simulation operating condition information to determine at least two charging static relaxation voltages corresponding to the pole piece size parameters includes:

[0014] Input preset simulation working condition information, and determine the rest time corresponding to the simulation working condition information through the electrochemical mechanism model, wherein the simulation working condition information includes temperature and charging rate, and the rest time includes charging rest time and discharging rest time;

[0015] A simulation is performed based on the simulation operating condition information, the rest time corresponding to the simulation operating condition information and the current pole piece size parameters to obtain at least two charging rest relaxation voltages corresponding to the pole piece size parameters.

[0016] The above method, optionally, if the judgment is reasonable, determines the current pole piece size parameter as the target pole piece size parameter of the battery under the simulation working condition information, and stores it in the simulation result database corresponding to the battery;

[0017] The simulation result database is used to store the target pole piece size parameters of the battery under different simulation conditions.

[0018] The above method, optionally, after storing the target pole piece size parameters of the battery under the simulation working condition information in the simulation result database corresponding to the battery, further comprises:

[0019] Receive test instructions;

[0020] In response to the test instruction, obtaining test condition information of the application scenario corresponding to the test instruction; the test condition information includes scene temperature information and scene charging rate required by the application scenario;

[0021] According to the maximum scene charging rate and the scene temperature information in the test condition information, query the simulation result database to obtain the target electrode size parameter corresponding to the test condition information;

[0022] Output the target pole piece size parameters corresponding to the test condition information.

[0023] The above method, optionally, before simulating to obtain at least two charge static relaxation voltages, further comprises:

[0024] Performing simulation according to the preset simulation working condition of the battery and the electrochemical mechanism model to obtain simulation voltage curve data;

[0025] Based on the simulated voltage curve data and the actual voltage curve data, the electrochemical mechanism model is corrected to obtain the target electrochemical mechanism model of the battery; the actual voltage curve data is the voltage curve data obtained by testing under actual operating conditions, and the actual operating conditions are the same as the preset simulation operating conditions.

[0026] A device for determining the size of a pole piece, comprising:

[0027] An acquisition unit, used to acquire the electrode size parameters of the battery to be designed and construct a corresponding electrochemical mechanism model, wherein the electrode size parameters at least include the difference between the width of the positive electrode and the width of the negative electrode;

[0028] An input unit, used for inputting preset simulation operating condition information to determine at least two charging static relaxation voltages corresponding to the pole piece size parameters;

[0029] A judging unit, used for judging the rationality of the pole piece size parameters according to the two charging static relaxation voltages;

[0030] The adjusting unit is used to adjust the pole piece size parameter if it is unreasonable, until the pole piece size parameter is judged to be reasonable based on two charging static relaxation voltages corresponding to the adjusted pole piece size parameter.

[0031] In the above device, optionally, the judging unit includes:

[0032] A judgment subunit is used to judge that the corresponding pole piece size parameters are reasonable if the difference between the two charging static relaxation voltages is less than a preset threshold; otherwise, it is judged to be unreasonable, wherein the two charging static relaxation voltages include a first charging static relaxation voltage and a second charging static relaxation voltage.

[0033] The above device may optionally further include:

[0034] A storage unit, for determining the current pole piece size parameter as the target pole piece size parameter of the battery under the simulation working condition information if the judgment is reasonable, and storing it in the simulation result database corresponding to the battery;

[0035] The simulation result database is used to store the target pole piece size parameters of the battery under different simulation conditions.

[0036] A storage medium includes stored instructions, wherein when the instructions are executed, the device where the storage medium is located is controlled to execute the above-mentioned method for determining the size of a pole piece.

[0037] An electronic device comprises a memory and one or more instructions, wherein the one or more instructions are stored in the memory and are configured to be executed by one or more processors to perform the above-mentioned method for determining the size of a pole piece.

[0038] Based on the above-mentioned implementation of this application, a method, device and storage medium for determining the size of a pole piece are provided, the method comprising: obtaining the pole piece size parameters of the battery to be designed, constructing a corresponding electrochemical mechanism model, the pole piece size parameters at least including the difference between the width of the positive pole piece and the width of the negative pole piece; inputting preset simulation operating condition information to determine at least two charging static relaxation voltages corresponding to the pole piece size parameters; judging the rationality of the pole piece size parameters according to the two charging static relaxation voltages; if unreasonable, adjusting the pole piece size parameters until the pole piece size parameters are judged to be reasonable according to the two charging static relaxation voltages corresponding to the adjusted pole piece size parameters. Applying the method provided in the embodiment of this application, the pole piece size parameters can be continuously iterated and optimized according to the simulation results of the electrochemical mechanism model, and the pole piece size parameters that finally meet the conditions are obtained, so that the optimal pole piece size parameters under specific operating conditions can be accurately determined. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0040] Figure 1 A method flow chart of a method for determining the size of a pole piece provided in this application;

[0041] Figure 2 A schematic diagram of a lateral diffusion mechanism process provided for this application;

[0042] Figure 3 An example diagram of a simulated voltage curve provided in this application;

[0043] Figure 4 This is an example diagram of a simulated voltage curve of a battery charging and discharging process provided in this application;

[0044] Figure 5 A schematic diagram of the structure of a device for determining the size of a pole piece provided in the present application;

[0045] Figure 6 A schematic diagram of the structure of an electronic device provided in this application. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0047] In this application, the terms "comprises", "comprising" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0048] Existing design methods face significant technical difficulties in determining the size parameters of the pole piece. First, the design parameters mostly rely on the engineer's experience and historical production data. This method is highly subjective and lacks systematic theoretical support. Due to the complex electrochemical behavior of lithium-ion batteries, especially the lateral diffusion of lithium ions during the charge and discharge cycle, it is difficult to accurately predict and quantify the direct impact of the pole piece size parameters on the lithium dendrite inhibition effect based on experience alone. Therefore, in actual applications, the pole piece size parameters are often conservatively or insufficiently designed, which affects the energy density and cycle life of the battery.

[0049] Based on this, the embodiment of the present application provides a method for determining the size of a pole piece, which can be applied to electronic devices, and the electronic devices can be computers, tablets, smart phones, and smart wearable devices, etc. The method flow chart of the method is as follows: Figure 1 As shown, specifically including:

[0050] S101: Acquire electrode sheet size parameters of a battery to be designed and construct a corresponding electrochemical mechanism model, wherein the electrode sheet size parameters at least include a difference between a width of a positive electrode sheet and a width of a negative electrode sheet.

[0051] In this embodiment, the electrochemical mechanism model may be a model for describing the chemical reactions and kinetic processes occurring in a battery; the battery may be a lithium battery.

[0052] Optionally, the electrode sheet size parameter may include the difference between the width of the positive electrode sheet and the width of the negative electrode sheet, that is, the size of the portion of one of the positive and negative electrode sheets that protrudes relative to the other electrode sheet; for example, it may be the size of the portion of the negative electrode sheet that protrudes relative to the positive electrode sheet in the width direction. It can be understood that when the positive electrode sheet and the negative electrode sheet are arranged opposite to each other, in the electrode sheet width direction, the distances at both ends of the negative electrode sheet that extend beyond the positive electrode sheet are equal, then half of the difference between the width of the positive electrode sheet and the width of the negative electrode sheet is the distances at which the two ends of the negative electrode sheet extend beyond the positive electrode sheet.

[0053] The specific implementation may include the following steps:

[0054] Obtaining battery design parameters, thermodynamic parameters, and kinetic parameters of the battery;

[0055] Based on a preset electrochemical model, the battery design parameters, the thermodynamic parameters, the kinetic parameters and a plurality of preset partial differential equations, an electrochemical mechanism model of the battery is constructed;

[0056] In this embodiment, the battery design parameters, thermodynamic parameters, and kinetic parameters of the battery to be designed are obtained, and based on the electrochemical reaction of the lithium battery and the P2D model proposed by Newman, multiple partial differential equations (solid phase lithium ion diffusion equation, solid phase charge conservation equation, liquid phase lithium ion diffusion equation, liquid phase charge conservation linearization equation, and Butler-Volumer equation) are coupled to establish an electrochemical mechanism model of the lithium ion battery.

[0057] Optionally, the battery design parameters may include the number of battery electrode layers, battery electrode thickness, battery electrode width, battery electrode height, battery current collector thickness, battery separator thickness, and battery electrode size parameters.

[0058] Optionally, the thermodynamic parameters may include gram capacity of the positive and negative electrode materials, particle radius of the positive and negative electrode materials, surface density of the positive and negative electrode materials, equilibrium potential of the positive and negative electrode materials, and entropy thermal coefficient of the positive and negative electrode materials.

[0059] Optionally, the kinetic parameters may include the solid phase diffusion coefficient of the positive and negative electrode materials, the positive and negative electrode reaction rate constants, the positive and negative electrode activation energy, the positive and negative electrode conductivity, the positive and negative electrode sheets and the diaphragm tortuosity, the electrolyte diffusion coefficient, the electrolyte conductivity, etc.

[0060] S102: inputting preset simulation operating condition information to determine at least two charging static relaxation voltages corresponding to the pole piece size parameters.

[0061] Optionally, the simulation operating condition information may include temperature and charging rate. The number of simulation operating condition information in this embodiment may be one or more. In this embodiment of the battery, the simulation operating condition parameters can be input into the electrochemical mechanism model, and then the simulation is performed to determine at least two charging static relaxation voltages corresponding to the pole piece size parameters. The charging static relaxation voltage is different for different temperatures and charging rates. According to different temperatures and charging rates, the charging static relaxation voltage can be directly determined by simulation, which can simplify the method and avoid a long experimental process.

[0062] Among them, the charging static relaxation voltage refers to the amplitude of the battery voltage drop after the battery is charged, stops charging and remains stationary for a period of time. Specifically, the charging static relaxation voltage is the difference between the static equilibrium voltage and the charging cut-off voltage, wherein the static equilibrium voltage is the voltage at both ends of the battery after the battery is charged, without any charging and discharging operation, and the charging cut-off voltage is the highest voltage that can be reached when the battery is charged, which is determined according to different battery systems. In this embodiment, each charging static relaxation voltage is obtained after each charging simulation, so that at least two different charging static relaxation voltages can be obtained by charge and discharge cycle simulation, and at least one discharge simulation is passed between the two charging static relaxation voltages. Specifically, after charging to the charging cut-off voltage, standing for a period of time, a charging static relaxation voltage can be obtained, and then discharged to the discharge cut-off voltage, charged again to the charging cut-off voltage, and standing for a period of time, another charging static relaxation voltage can be obtained, and so on, multiple charging static relaxation voltages can be obtained. Preferably, the charge cut-off voltage may be the full charge cut-off voltage, and the discharge cut-off voltage may be the full discharge cut-off voltage, so that by fully charging and fully discharging the battery, it is convenient to comprehensively evaluate the battery performance and avoid safety hazards.

[0063] Optionally, after constructing the initial electrochemical mechanism model and obtaining the relevant operating conditions of the battery to be designed, the preset simulation conditions, including the preset temperature and the preset charging rate, are determined, and the measured voltage curve data of the same preset temperature and charging rate (for example, 25°C, 45°C and 0°C, different charging rates) are input, and fit with the high and low temperature voltage curve data calculated by the coupling model. The fitting method is based on the parameter estimation method of the least squares method. By calibrating the 0.33C and 1C voltage curves at three temperatures, the capacity, voltage, positive and negative electrode concentrations and temperature-related activation energy, solid and liquid phase diffusion coefficients and positive and negative electrode exchange current density calculated by the model are calibrated, so that the capacity output by the model conforms to the actual designed capacity value, and appropriate activation energy, diffusion coefficient and exchange current density are selected at different temperatures.

[0064] S103: judging the rationality of the pole piece size parameters according to the two charging static relaxation voltages.

[0065] In this embodiment, the step of judging the rationality of the pole piece size parameters according to the two charging static relaxation voltages includes: if the difference between the two charging static relaxation voltages is less than a preset threshold value, then judging that the corresponding pole piece size parameters are reasonable; otherwise, judging that they are unreasonable.

[0066] The basis for judgment lies in the lateral diffusion mechanism of lithium ions:

[0067] like Figure 2 The figure shows the lateral diffusion process of lithium batteries. Figure 2 Stage a: The battery is charged, lithium ions are deintercalated from the positive electrode, and the concentration of lithium ions embedded in the negative electrode increases, reaching the overhang area of ​​the battery (the area where the negative electrode sheet exceeds the positive electrode sheet) when fully charged, and there is no diffusion of charged lithium ions; Figure 2 Stage b: During the full charge relaxation and rest stage, lithium ions diffuse inside the negative electrode, and some of them diffuse into the overhang area. At this time, the voltage detected during rest will drop. Figure 2 Stage c: discharge after resting, the negative electrode is deintercalated, the concentration of lithium ions embedded in the positive electrode increases, and the lithium ions embedded in the Overhagn area under full discharge are also embedded in the positive electrode; Figure 2 Stage d: Discharge and standstill, at this time, the lithium ions in the overhang area of ​​the negative electrode have completely diffused to the positive electrode, and the concentration will increase to a certain extent; Figure 2 Stage e: When charging again, since the positive electrode stores lithium ions from the Overhang area, the concentration of lithium ions diffused to the negative electrode at the end of charging is too high. Since the lithium ions are embedded in a one-to-one manner, the excess lithium ions cannot be embedded and precipitated, resulting in lithium precipitation.

[0068] In this embodiment, the pole piece size parameters are determined by the lateral diffusion mechanism, which can improve the accuracy of the pole piece size parameters. Specifically, the difference between the two charging static relaxation voltages can be used to determine whether the battery is lithium deposited, thereby determining whether the pole piece size parameters are reasonable, simplifying the method, and improving design efficiency.

[0069] Among them, the two charging static relaxation voltages include the first charging static relaxation voltage and the second charging static relaxation voltage. The first charging static relaxation voltage is the charging static relaxation voltage obtained after the battery is charged to the charging cut-off voltage for the first time, and the second charging static relaxation voltage is the charging static relaxation voltage obtained after the battery is charged to the charging cut-off voltage for the first time, discharged to the discharge cut-off voltage, and charged to the charging cut-off voltage again. The first charging static relaxation voltage and the second charging static relaxation voltage are selected because as the charge and discharge cycle proceeds, the battery will decay due to electrolyte drying, loss of circulated lithium, etc., thereby increasing the overall battery impedance, weakening the lithium ion diffusion capacity, and decreasing the voltage, thereby affecting the diffusion concentration of lithium ions in the negative electrode Overhang, so that the obtained electrode size parameters are not the maximum optimal solution. In the present application, full charge and discharge conditions are adopted. According to the lateral diffusion mechanism of lithium batteries, the first charge static relaxation voltage and the second charge static relaxation voltage are selected for comparison. The lithium ion diffusion is least affected by the number of cycles. The first charge static relaxation voltage simulation data is selected to avoid the occurrence of these side reactions and avoid lithium precipitation. The second charge static relaxation voltage is used to minimize the attenuation effect, and the voltage values ​​between the two times are closer, thereby improving the overall accuracy. Optionally, the first charge static relaxation voltage is defined as the first voltage difference ΔU1, and the second charge static relaxation voltage is defined as the second voltage difference ΔU2. The difference between the first voltage difference ΔU1 and the second voltage difference ΔU2 can be calculated, and then the difference between ΔU1 and ΔU2 can be compared with a preset threshold to determine whether the difference is greater than the preset difference threshold. See. Figure 3 , is an example diagram of a simulated voltage curve during a battery charging process provided in this application.

[0070] Optionally, the preset difference threshold value can be set according to actual needs, for example, it can be set to 0, 10mV, 20mV, 30mV, 40mV, 50mV and other values.

[0071] Optionally, the first voltage difference is calculated as follows:

[0072] ΔU1=U1-U0

[0073] Among them, ΔU1 is the first voltage difference, that is, the first charging static relaxation voltage, U1 is the first charging static balance voltage of the battery, that is, the first charging static balance voltage, and U0 is the first full charging cut-off voltage of the battery.

[0074] The second voltage difference is calculated as follows:

[0075] ΔU2=U4-U3

[0076] Among them, ΔU2 is the second voltage difference, that is, the second charging static relaxation voltage, U4 is the second charging static balance voltage of the battery, that is, the second charging static balance voltage, and U3 is the second full charging cut-off voltage of the battery.

[0077] Under the preset temperature, charging rate and electrode size parameter conditions, if |ΔU1-ΔU2|≤30mV, it is judged that the electrode size parameters at this time are reasonable.

[0078] Preferably, when |ΔU1-ΔU2| is smaller, a better solution for the corresponding pole piece size parameters under the current working conditions can be output; when |ΔU1-ΔU2| approaches zero, the optimal solution for the corresponding pole piece size parameters under the current working conditions can be output; the preset threshold can be configured as needed to take into account both the simulation efficiency and the accuracy of the pole piece size parameters.

[0079] S104: If it is unreasonable, adjusting the pole piece size parameter until the pole piece size parameter is judged to be reasonable based on two charging static relaxation voltages corresponding to the adjusted pole piece size parameter.

[0080] In this embodiment, the width of the pole piece size parameter can be increased or decreased, thereby adjusting the pole piece size parameter and obtaining a new simulated pole piece size parameter. By using the method provided in the embodiment of the present application, the pole piece size parameter can be continuously optimized iteratively according to the simulation results of the electrochemical mechanism model, and the pole piece size parameter that finally meets the conditions can be obtained, and the optimal pole piece size parameter under specific working conditions can be accurately determined.

[0081] It should be noted that if only the pole piece width needs to be adjusted, the pole piece length can be set to an equal length or a fixed value to adjust the pole piece width. If only the pole piece length is required, the pole piece width can be set to an equal width or a fixed value to adjust the pole piece length. If the pole piece length and width need to be adjusted, the pole piece length and width can be adjusted synchronously according to the above principle, which will not be repeated here.

[0082] In some embodiments, there may be multiple simulated operating condition information. In this case, the processes S102 to S104 may be performed for each simulated operating condition information respectively, so as to obtain the target pole piece size parameters of the battery under each simulated operating condition information.

[0083] In some embodiments, the step of inputting preset simulation operating condition information to determine at least two charging static relaxation voltages corresponding to the pole piece size parameters includes:

[0084] Input preset simulation working condition information, and determine the rest time corresponding to the simulation working condition information through the electrochemical mechanism model, wherein the simulation working condition information includes temperature and charging rate, and the rest time includes charging rest time and discharging rest time;

[0085] A simulation is performed based on the simulation operating condition information, the rest time corresponding to the simulation operating condition information and the current pole piece size parameters to obtain at least two charging rest relaxation voltages corresponding to the pole piece size parameters.

[0086] In this embodiment, different simulation working condition information may correspond to different resting times, and the resting time may include a charging resting time and a discharging resting time. Further, each charging resting relaxation voltage corresponds to a charging resting time and a discharging resting time.

[0087] Optionally, simulation may be performed using an electrochemical mechanism model and simulation operating condition information to obtain a static time corresponding to the simulation operating condition information.

[0088] The rest time varies with the charging rate. Different rates have different diffusion capacities, and the corresponding rest time is also different. In this embodiment, the rest time is simulated by simulating the working condition information and the preset pole piece size parameters. Different rest times can be determined according to different time periods to improve the accuracy of the rest time. For example, assuming that 0.5h is to ensure that the lateral diffusion time of lithium ions is sufficient, the first equilibrium voltage value will be obtained at this time. This voltage value is the required static equilibrium voltage, and 0.5h is the rest time at this time; assuming that 0.6h is to ensure that the lateral diffusion time of lithium ions is sufficient, the second equilibrium voltage value will be obtained at this time. This voltage value is the required static equilibrium voltage, and 0.6h is the rest time at this time.

[0089] See also Figure 4 , is an example diagram of a simulated voltage curve of a battery charging and discharging process provided in an embodiment of the present application, wherein the duration of the equilibrium voltage appearing in the rate charging and charging resting stages can be recorded as the charging resting time (t ch ); that is, t ch =T2-T1. The duration of the equilibrium voltage during the rate discharge and the discharge rest period is recorded as the discharge rest time (t dch ). That is: t_dch = T4-T3. That is, each charge corresponds to a charge rest time, and each discharge corresponds to a discharge rest time, so that the first charge rest relaxation voltage corresponds to a charge rest time (no discharge rest time is required at this time), and the second charge rest relaxation voltage corresponds to a discharge rest time and another charge rest time.

[0090] By determining the charging standstill time through simulation, the static equilibrium voltage can be quickly and accurately determined to ensure the balance of chemical reactions, while by determining the discharge standstill time through simulation, the time for the second charge can be quickly and accurately determined, reducing the overall impact of battery polarization and improving the overall simulation efficiency. It should be noted that in the existing experiments, three different standstill time settings were set for the battery, namely 5 minutes, 10 minutes and 30 minutes. These settings are based on enterprise standard regulations, and the main purpose is to save experimental time and cost. However, the selected time length is not specifically optimized for whether the battery voltage has completely reached a static equilibrium state; that is, at the end of these specific time periods, the battery voltage may still be changing and has not yet reached the final steady-state value. In view of this, it is particularly important to use a simulation method in this embodiment to determine a more accurate standstill time, because the simulation can simulate the dynamic process inside the battery more carefully, helping to find an optimal standstill time that can ensure that the voltage is basically stable and take into account efficiency, thereby improving the accuracy and practicality of the experimental results.

[0091] In one embodiment provided in the present application, based on the above-mentioned implementation process, optionally, if it is judged to be reasonable, the current pole piece size parameter is determined as the target pole piece size parameter of the battery under the simulation working condition information, and stored in the simulation result database corresponding to the battery; the simulation result database is used to store the target pole piece size parameters of the battery under different simulation working conditions.

[0092] In this embodiment, the target pole piece size parameter is the optimal pole piece size parameter of the battery under the simulation working condition information. The target pole piece size parameter can be used as the design value of the battery.

[0093] Optionally, the simulation working condition information, simulation results and target electrode size parameters of the battery can be associated and stored in a simulation result database, wherein Table 1 is shown, which shows a record table between the simulation working condition information, simulation results and target Overhang of the battery, as follows:

[0094] Table 1

[0095]

[0096] Where T is temperature and C_rate is charge rate.

[0097] In this embodiment, the target electrode size parameters of the battery under each simulation condition information can be stored in the simulation result database, which is used to record the target electrode size parameters of the battery under different temperatures and different charging rates; the content recorded in the simulation result database can be shown in Table 2:

[0098] Table 2

[0099]

[0100]

[0101] In an embodiment provided by the present application, based on the above implementation process, optionally, after storing the target pole piece size parameter of the battery under the simulation working condition information in the simulation result database corresponding to the battery, it also includes:

[0102] Receive test instructions;

[0103] In response to the test instruction, obtaining test condition information of the application scenario corresponding to the test instruction; the test condition information includes scene temperature information and scene charging rate required by the application scenario;

[0104] According to the maximum scene charging rate and the scene temperature information in the test condition information, query the simulation result database to obtain the target electrode size parameter corresponding to the test condition information;

[0105] Output the target pole piece size parameters corresponding to the test condition information.

[0106] In this embodiment, the number of scenario charging rates required for the application scenario may be one or more.

[0107] In order to clearly introduce the solution of this application, the process of outputting the target pole piece size parameters corresponding to the test condition information is illustrated below by way of example:

[0108] For example, the battery is designed in the battery design stage, and the battery requirements include: battery size, test condition information of the battery in the application scenario, the scene temperature information in the test condition information is room temperature 25°C, and the scene charging rate includes 0.33C, 1C, 2C, etc. First, the simulation imports the design parameter information into the proofread model in the design stage, and inputs the scene temperature of the design application scenario of the battery, and inputs the working condition current 0.33C, 1C, and 2C respectively. According to the method of this application, the target electrode size parameters that meet the requirements of each working condition are calculated and stored in the simulation result database; if the battery is charged and discharged at a rate of 1C, the target electrode size parameters of 1C are selected in the simulation result database. When the battery is fast charged, the test rate range is between 0.33C and 2C. At this time, the maximum Overhang value of the three rate conditions is selected in the simulation result database as the design size, which can meet the size requirements and avoid the risk of lithium plating, and at the same time avoid the insufficiency and redundancy of the size design, saving costs and design cycle time.

[0109] In this embodiment, the simulation process can be: charging to the full charge cut-off voltage, then standing for a first charge standstill time, and using the voltage across the battery at this time as the first charge standstill balance voltage; discharging the battery to the discharge cut-off voltage, then standing for a discharge standstill time, then charging to the full charge cut-off voltage, and then standing for a second charge standstill time, and using the voltage across the battery at this time as the second charge standstill balance voltage.

[0110] Optionally, the full charge and discharge cut-off voltage is a value related to the battery system. The lithium insertion range potential of the ternary full battery is 2.5-4.35V, and that of iron lithium is 2-3.65V. It is the potential characteristic of the material itself. That is, the corresponding full charge cut-off voltage and full discharge cut-off voltage are determined according to the range potential corresponding to the battery system and input into the model in advance.

[0111] In this embodiment, the size of the pole piece is calculated by changing the pole piece size parameters to make the first charge static relaxation voltage and the second charge static relaxation voltage similar under the working condition. This scheme can be used for multiple working conditions to select the corresponding pole piece size parameters as the design input value based on the actual charging working condition. The lithium ion diffusion rate is different for charging at different rates, and the lateral diffusion distance is also different, so the voltage drop is also different. Therefore, the selection of the working current is based on the maximum working current of the three-pole piece data without lithium precipitation. The optimal pole piece size parameters corresponding to each other from the minimum rate charging working condition to the maximum rate working condition can be output, and the optimal solution under each working condition is used as the design value. In actual applications, under the maximum rate working condition, the corresponding size is the maximum optimal solution, and the solution obtained under the other working conditions is less than this value. The size can be applied to different working conditions, but it will increase the cost, but it can reduce the simulation workload.

[0112] In an embodiment provided in the present application, based on the above implementation process, optionally, before simulating and obtaining at least two charging static relaxation voltages, the method further includes:

[0113] Performing simulation according to the preset simulation working condition of the battery and the electrochemical mechanism model to obtain simulation voltage curve data;

[0114] Based on the simulated voltage curve data and the actual voltage curve data, the electrochemical mechanism model is corrected to obtain the target electrochemical mechanism model of the battery; the actual voltage curve data is the voltage curve data obtained by testing under actual operating conditions, and the actual operating conditions are the same as the preset simulation operating conditions.

[0115] In this embodiment, the preset simulation working conditions may include a preset temperature and a preset charging rate. The measured voltage curve data of the same preset temperature and charging rate are input and fitted with the high and low temperature voltage curve data calculated by the electrochemical mechanism model. The fitting method is based on the parameter estimation method of the least squares method. By calibrating the voltage curves at different temperatures and charging rates, the capacity, voltage, positive and negative electrode concentrations, and temperature-related activation energy, solid and liquid phase diffusion coefficients, and positive and negative electrode exchange current density calculated by the electrochemical mechanism model are calibrated, so that the capacity output by the electrochemical mechanism model is consistent with the actual designed capacity value, and appropriate activation energy, diffusion coefficient, and exchange current density are selected at different temperatures.

[0116] Optionally, to calibrate the voltage curve, first use the 0.05C small rate discharge data of the positive and negative electrode materials as the baseline of the voltage curve, assuming that the voltage polarization calculated at this time is extremely small and is regarded as a state of negligible polarization, and then input the battery size, positive and negative electrode gram capacity, density, active material ratio, and test temperature and other parameters, input the existing actual test to obtain 0.33C, 1C high and low temperature voltage curves, and adjust the capacity, diffusion coefficient, tortuosity and other parameters to make the electrochemical mechanism model reach the design accuracy. The choice of discharge rate should be calibrated according to the rate range provided by the design. For example, if the charging rate range of the battery to be calculated is 0.33C~2C, then the voltage curve under the corresponding rate needs to be benchmarked during calibration to ensure the rationality of the battery parameter correction under different working conditions within the accuracy range.

[0117] and Figure 1 Corresponding to the method described above, the embodiment of the present application also provides a device for determining the size of a pole piece, for determining the size of a pole piece Figure 1 The specific implementation of the method in the embodiment of the present invention is shown in the structural diagram of the device. Figure 5 As shown, including:

[0118] An acquisition unit 501 is used to acquire the electrode size parameters of the battery to be designed and construct a corresponding electrochemical mechanism model, wherein the electrode size parameters at least include the difference between the width of the positive electrode and the width of the negative electrode;

[0119] An input unit 502, used to input preset simulation operating condition information to determine at least two charging static relaxation voltages corresponding to the pole piece size parameters;

[0120] A judging unit 503, configured to judge the rationality of the pole piece size parameters according to the two charging static relaxation voltages;

[0121] The adjusting unit 504 is used to adjust the pole piece size parameter if it is unreasonable, until the pole piece size parameter is judged to be reasonable based on two charging static relaxation voltages corresponding to the adjusted pole piece size parameter.

[0122] In an embodiment provided in the present application, based on the above solution, optionally, the judging unit 503 includes:

[0123] A judgment subunit is used to judge that the corresponding pole piece size parameters are reasonable if the difference between the two charging static relaxation voltages is less than a preset threshold; otherwise, it is judged to be unreasonable, wherein the two charging static relaxation voltages include a first charging static relaxation voltage and a second charging static relaxation voltage.

[0124] In an embodiment provided in the present application, based on the above solution, optionally, it further includes:

[0125] A storage unit, for determining the current pole piece size parameter as the target pole piece size parameter of the battery under the simulation working condition information if the judgment is reasonable, and storing it in the simulation result database corresponding to the battery;

[0126] The simulation result database is used to store the target pole piece size parameters of the battery under different simulation conditions.

[0127] In an embodiment provided in the present application, based on the above solution, optionally, the input unit 502 includes:

[0128] An input subunit, used to input preset simulation condition information, and determine the rest time corresponding to the simulation condition information through the electrochemical mechanism model, wherein the simulation condition information includes temperature and charging rate, and the rest time includes charging rest time and discharging rest time;

[0129] The simulation subunit is used to perform simulation based on the simulation working condition information, the static time corresponding to the simulation working condition information and the current pole piece size parameters to obtain at least two charging static relaxation voltages corresponding to the pole piece size parameters.

[0130] In an embodiment provided in the present application, based on the above solution, optionally, it further includes:

[0131] A receiving unit, used for receiving a test instruction;

[0132] An execution unit, configured to obtain, in response to the test instruction, test condition information of an application scenario corresponding to the test instruction; the test condition information includes scene temperature information and scene charging rate required by the application scenario;

[0133] A query unit, configured to query the simulation result database according to the maximum scene charging rate and the scene temperature information in the test condition information, and obtain a target electrode size parameter corresponding to the test condition information;

[0134] The output unit is used to output the target pole piece size parameters corresponding to the test condition information.

[0135] In an embodiment provided in the present application, based on the above solution, optionally, it further includes:

[0136] A simulation unit, used to perform simulation according to a preset simulation operating condition of the battery and the electrochemical mechanism model to obtain simulation voltage curve data;

[0137] A correction unit is used to correct the electrochemical mechanism model based on the simulated voltage curve data and the actual voltage curve data to obtain a target electrochemical mechanism model of the battery; the actual voltage curve data is voltage curve data obtained by testing under actual operating conditions, and the actual operating conditions are the same as the preset simulation operating conditions.

[0138] The specific principles and execution processes of each unit and module in the pole piece size determination device disclosed in the above-mentioned embodiment of the present application are the same as the pole piece size determination method disclosed in the above-mentioned embodiment of the present application. Please refer to the corresponding parts of the pole piece size determination method provided in the above-mentioned embodiment of the present application, and will not be repeated here.

[0139] An embodiment of the present application further provides a storage medium, which includes stored instructions, wherein when the instructions are executed, the device where the storage medium is located is controlled to execute the above-mentioned method for determining the size of the pole piece.

[0140] The present application also provides an electronic device, whose structural diagram is as follows: Figure 6 As shown, it specifically includes a memory 601 and one or more instructions 602, wherein the one or more instructions 602 are stored in the memory 601 and are configured to be executed by one or more processors 603 to perform the following operations:

[0141] Obtaining the electrode size parameters of the battery to be designed and constructing a corresponding electrochemical mechanism model, wherein the electrode size parameters at least include the difference between the width of the positive electrode and the width of the negative electrode;

[0142] Inputting preset simulation operating condition information to determine at least two charging static relaxation voltages corresponding to the pole piece size parameters;

[0143] Judging the rationality of the pole piece size parameters according to the two charging static relaxation voltages;

[0144] If it is unreasonable, the pole piece size parameter is adjusted until the pole piece size parameter is judged to be reasonable based on two charging static relaxation voltages corresponding to the adjusted pole piece size parameter.

[0145] It should be noted that each embodiment in this specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other. For the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0146] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.

[0147] For the convenience of description, the above device is described in various units according to their functions. Of course, when implementing the present application, the functions of each unit can be implemented in the same or multiple software and / or hardware.

[0148] It can be known from the description of the above implementation methods that those skilled in the art can clearly understand that the present application can be implemented by means of software plus a necessary general hardware platform. Based on such an understanding, the technical solution of the present application can be essentially or partly contributed to the prior art in the form of a software product, which can be stored in a storage medium such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in the various embodiments of the present application or certain parts of the embodiments.

[0149] The above is a detailed introduction to a method for determining the size of a pole piece provided in the present application. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea; at the same time, for general technical personnel in this field, based on the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A method for determining the size of a pole piece, characterized in that: include: Obtaining the electrode size parameters of the battery to be designed and constructing a corresponding electrochemical mechanism model, wherein the electrode size parameters at least include the difference between the width of the positive electrode and the width of the negative electrode; Inputting preset simulation operating condition information to determine at least two charging static relaxation voltages corresponding to the pole piece size parameters; Judging the rationality of the pole piece size parameters according to the two charging static relaxation voltages; If it is unreasonable, the pole piece size parameter is adjusted until the pole piece size parameter is judged to be reasonable based on two charging static relaxation voltages corresponding to the adjusted pole piece size parameter.

2. The method according to claim 1, characterized in that The step of judging the rationality of the pole piece size parameters according to the two charging static relaxation voltages comprises: If the difference between the two charging static relaxation voltages is less than a preset threshold, the corresponding pole piece size parameters are judged to be reasonable; otherwise, they are judged to be unreasonable, wherein the two charging static relaxation voltages include a first charging static relaxation voltage and a second charging static relaxation voltage.

3. The method according to claim 1, characterized in that The step of inputting preset simulation operating condition information to determine at least two charging static relaxation voltages corresponding to the pole piece size parameters includes: Input preset simulation working condition information, and determine the rest time corresponding to the simulation working condition information through the electrochemical mechanism model, wherein the simulation working condition information includes temperature and charging rate, and the rest time includes charging rest time and discharging rest time; A simulation is performed based on the simulation operating condition information, the rest time corresponding to the simulation operating condition information and the current pole piece size parameters to obtain at least two charging rest relaxation voltages corresponding to the pole piece size parameters.

4. The method according to claim 1, characterized in that: If the judgment is reasonable, the current pole piece size parameter is determined as the target pole piece size parameter of the battery under the simulation working condition information, and stored in the simulation result database corresponding to the battery; The simulation result database is used to store the target pole piece size parameters of the battery under different simulation conditions.

5. The method according to claim 4, characterized in that After storing the target pole piece size parameters of the battery under the simulation working condition information in the simulation result database corresponding to the battery, the method further includes: Receive test instructions; In response to the test instruction, obtaining test condition information of the application scenario corresponding to the test instruction; the test condition information includes scene temperature information and scene charging rate required by the application scenario; According to the maximum scene charging rate and the scene temperature information in the test condition information, query the simulation result database to obtain the target electrode size parameter corresponding to the test condition information; Output the target pole piece size parameters corresponding to the test condition information.

6. The method according to claim 3, characterized in that Before simulating to obtain at least two charge rest relaxation voltages, the method further includes: Performing simulation according to the preset simulation working condition of the battery and the electrochemical mechanism model to obtain simulation voltage curve data; Based on the simulated voltage curve data and the actual voltage curve data, the electrochemical mechanism model is corrected to obtain the target electrochemical mechanism model of the battery; the actual voltage curve data is the voltage curve data obtained by testing under actual operating conditions, and the actual operating conditions are the same as the preset simulation operating conditions.

7. A device for determining the size of a pole piece, characterized in that: include: An acquisition unit, used to acquire the electrode size parameters of the battery to be designed and construct a corresponding electrochemical mechanism model, wherein the electrode size parameters at least include the difference between the width of the positive electrode and the width of the negative electrode; An input unit, used for inputting preset simulation operating condition information to determine at least two charging static relaxation voltages corresponding to the pole piece size parameters; A judging unit, used for judging the rationality of the pole piece size parameters according to the two charging static relaxation voltages; The adjusting unit is used to adjust the pole piece size parameter if it is unreasonable, until the pole piece size parameter is judged to be reasonable based on two charging static relaxation voltages corresponding to the adjusted pole piece size parameter.

8. The device according to claim 6, characterized in that The judging unit comprises: A judgment subunit is used to judge that the corresponding pole piece size parameters are reasonable if the difference between the two charging static relaxation voltages is less than a preset threshold; otherwise, it is judged to be unreasonable, wherein the two charging static relaxation voltages include a first charging static relaxation voltage and a second charging static relaxation voltage.

9. The device according to claim 7, characterized in that Also includes: A storage unit, for determining the current pole piece size parameter as the target pole piece size parameter of the battery under the simulation working condition information if the judgment is reasonable, and storing it in the simulation result database corresponding to the battery; The simulation result database is used to store the target pole piece size parameters of the battery under different simulation conditions.

10. A storage medium, characterized in that: The storage medium includes stored instructions, wherein when the instructions are executed, the device where the storage medium is located is controlled to execute the method for determining the size of the pole piece according to any one of claims 1 to 6.

Images