Method for determining current boundary of lithium battery and storage medium

Abstract

The invention discloses a method for determining a current boundary of a lithium battery and a storage medium. The method relates to the technical field of batteries, and comprises the following steps: acquiring a first current value corresponding to a target battery under a plurality of temperature values, the first current value being a maximum current value of the target battery under the condition of no lithium precipitation; under the condition of the first current value, simulation is carried out through a preset electrochemical-three-dimensional thermal model of the target battery, a target negative electrode potential is obtained, and the target negative electrode potential is the minimum negative electrode potential of the target battery under the condition that lithium is not separated out; and obtaining a charging current boundary value of the target battery according to the target open-circuit voltage-state-of-charge curve and the target cathode potential of the target battery. Through the method and the device, the problem that the fast charging performance boundary of charging after discharging cannot be determined in the prior art is solved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a method for determining a current boundary of a lithium battery and a storage medium. Background Art

[0002] For the calibration of the fast charging performance boundary of the battery, in existing studies, actual measurement or actual measurement combined with simulation methods are mostly used, and when calibrating the boundary, most of them only consider the fast charging performance boundary in the charging direction, and rarely consider the process of charging after discharge. There is a difference in the OCV (Open circuit voltage) of lithium-ion batteries at the same SOC (State of Charge) between charging and discharging, which is the voltage hysteresis phenomenon. In existing studies, in order to reduce the deviation caused by voltage hysteresis, methods such as charging / discharging average OCV and adjusting model parameters are usually used in the model. Although these methods have reduced the voltage estimation deviation caused by voltage hysteresis to a certain extent, there is still a certain deviation when evaluating the working conditions of charging after discharge, which cannot accurately reflect the true state of the battery, affecting the accuracy of the fast charging performance boundary evaluation of such working conditions as charging after discharge. Summary of the invention

[0003] The main purpose of the present application is to provide a method and storage medium for determining the current boundary of a lithium battery, so as to solve the problem in the related art that the fast charging performance boundary of charging after discharge cannot be determined.

[0004] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a method for determining the current boundary of a lithium battery is provided. The method comprises: obtaining a first current value corresponding to a target battery at multiple temperature values, wherein the first current value is the maximum current value of the target battery without lithium precipitation; in the case of the first current value, simulating the preset electrochemical-three-dimensional thermal model of the target battery to obtain a target negative electrode potential, wherein the target negative electrode potential is the minimum negative electrode potential of the target battery without lithium precipitation; according to the target open circuit voltage-state of charge curve of the target battery and the target negative electrode potential, obtaining the charging current boundary value of the target battery, wherein the target open circuit voltage-state of charge curve is obtained by discharging and then charging the target battery.

[0005] Further, under the condition of the first current value, simulation is performed through the preset electrochemical-three-dimensional thermal model of the target battery to obtain the target negative electrode potential, including: under the condition of the first current value, charging simulation is performed through the preset electrochemical-three-dimensional thermal model of the target battery to obtain the initial negative electrode potential; based on the initial negative electrode potential, multiple gradient negative electrode potentials are generated; under the multiple gradient negative electrode potentials, simulation is performed through the preset electrochemical-three-dimensional thermal model of the target battery to obtain the target negative electrode potential.

[0006] Furthermore, under the multiple gradient negative electrode potentials, simulation is performed through the preset electrochemical-three-dimensional thermal model of the target battery to obtain the target negative electrode potential, including: for each gradient negative electrode potential, at multiple temperature values, simulation calculation is performed through the electrochemical-three-dimensional thermal model to obtain multiple second current values ​​under charge states; charge and discharge cycle treatment is performed on the target battery according to the gradient negative electrode potential and the second current values ​​under the multiple charge states to obtain a treated target battery; state information of the treated target battery is obtained, and the target negative electrode potential is determined from the multiple gradient negative electrode potentials according to the state information, wherein the state information is used to characterize whether lithium deposition occurs in the target battery.

[0007] Furthermore, before simulating the target negative electrode potential through the preset electrochemical-three-dimensional thermal model of the target battery, the method also includes: constructing an electrochemical model based on the chemical reaction parameters of the target battery; constructing a three-dimensional thermal model based on the heat transfer parameters of the target battery; and coupling the electrochemical model and the three-dimensional thermal model to obtain the electrochemical-three-dimensional thermal model.

[0008] Furthermore, before obtaining the charging current boundary value of the target battery based on the target open circuit voltage-state of charge curve of the target battery and the target negative electrode potential, the method also includes: discharging the target battery to multiple states of charge to obtain the target battery in each state of charge; charging the target battery in each state of charge to obtain the open circuit voltage-state of charge curve of each state of charge; and determining the target open circuit voltage-state of charge curve based on the open circuit voltage-state of charge curve of each state of charge.

[0009] Furthermore, according to the target open circuit voltage-state of charge curve and the target negative electrode potential of the target battery, obtaining the charging current boundary value of the target battery includes: transmitting the data corresponding to the target open circuit voltage-state of charge curve to the electrochemical-three-dimensional thermal model; taking the target negative electrode potential as a control condition, performing charging simulation processing on the electrochemical-three-dimensional thermal model to obtain the maximum charging current value; and obtaining the charging current boundary value of the target battery according to the maximum charging current value.

[0010] Furthermore, obtaining the first current value corresponding to the target battery at multiple temperature values ​​includes: determining multiple temperature values ​​based on the working conditions of the target battery; charging the target battery at each temperature value; and obtaining the first current value during the charging process of the target battery.

[0011] Furthermore, coupling the electrochemical model and the three-dimensional thermal model to obtain the electrochemical-three-dimensional thermal model includes: coupling the electrochemical model and the three-dimensional thermal model to obtain an initial electrochemical-three-dimensional thermal model; performing simulation verification on the initial electrochemical-three-dimensional thermal model to obtain a verification result; and optimizing and adjusting the initial electrochemical-three-dimensional thermal model based on the verification result to obtain the electrochemical-three-dimensional thermal model.

[0012] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a computer-readable storage medium is provided, wherein the storage medium stores a program, wherein when the program is running, the device where the storage medium is located is controlled to execute any one of the above-mentioned methods for determining the current boundary of a lithium battery.

[0013] In order to achieve the above-mentioned purpose, according to another aspect of the present application, an electronic device is also provided, the electronic device includes one or more processors and a memory, and the memory is used to store the method for determining the current boundary of a lithium battery described in any one of the above-mentioned methods implemented by one or more processors.

[0014] Through the present application, the following steps are adopted: obtaining a first current value corresponding to a target battery at multiple temperature values, wherein the first current value is the maximum current value of the target battery without lithium precipitation; under the first current value, simulating through a preset electrochemical-three-dimensional thermal model of the target battery to obtain a target negative electrode potential, wherein the target negative electrode potential is the minimum negative electrode potential of the target battery without lithium precipitation; obtaining a charging current boundary value of the target battery based on a target open circuit voltage-state of charge curve and a target negative electrode potential of the target battery, wherein the target open circuit voltage-state of charge curve is obtained by discharging and then charging the target battery, thereby solving the problem in the related art that the boundary of fast charging performance of charging after discharging cannot be determined. In this scheme, the minimum negative electrode potential of the target battery without lithium precipitation is obtained by the maximum current without lithium precipitation at different temperature values, and then the target open circuit voltage-state of charge curve and the target negative electrode potential are obtained by discharging and then charging the target battery to determine the charging current boundary value of the target battery. The target open circuit voltage-state of charge curve fully takes into account the influence of voltage hysteresis, and can more accurately evaluate the fast charging performance boundary of the battery in this case, providing a reference for improving the fast charging rate in actual battery applications, thereby achieving the effect of increasing the battery charging rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0016] Figure 1The process of the method for determining the current boundary of a lithium battery provided in the embodiment of the present application is as follows Figure 1 ;

[0017] Figure 2 The lithium battery simulation diagram provided in the embodiment of the present application is Figure 1 ;

[0018] Figure 3 is an OCV-SOC curve diagram of a lithium battery provided according to an embodiment of the present application;

[0019] Figure 4 The lithium battery simulation diagram provided in the embodiment of the present application is Figure 2 ;

[0020] Figure 5 The process of the method for determining the current boundary of a lithium battery provided in the embodiment of the present application is as follows Figure 2 ;

[0021] Figure 6 is a schematic diagram of a device for determining a current boundary of a lithium battery provided in an embodiment of the present application;

[0022] Figure 7 is a schematic diagram of an electronic device provided according to an embodiment of the present application. DETAILED DESCRIPTION

[0023] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0024] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings 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 should fall within the scope of protection of the present application.

[0025] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0026] It should be noted that the relevant information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for display, data for analysis, etc.) involved in this disclosure are all information and data authorized by the user or fully authorized by all parties. For example, an interface is set between this system and the relevant user or organization. Before obtaining relevant information, it is necessary to send an acquisition request to the aforementioned user or organization through the interface, and obtain relevant information after receiving the consent information fed back by the aforementioned user or organization.

[0027] The present invention is described below in conjunction with preferred implementation steps. Figure 1 The process of the method for determining the current boundary of a lithium battery provided in the embodiment of the present application is as follows Figure 1 ,like Figure 1 As shown, the method comprises the following steps:

[0028] Step S101, obtaining a first current value corresponding to a target battery at multiple temperature values, wherein the first current value is a maximum current value of the target battery without lithium deposition.

[0029] Optionally, multiple temperature values ​​are determined according to the working conditions of the target battery, and then the target battery is charged at each temperature value to obtain the maximum current value of the target battery without lithium deposition, that is, to obtain the above-mentioned first current value.

[0030] Step S102, under the condition of the first current value, a preset electrochemical-three-dimensional thermal model of the target battery is used for simulation to obtain a target negative electrode potential, wherein the target negative electrode potential is the minimum negative electrode potential of the target battery without lithium deposition.

[0031] Optionally, after obtaining the above-mentioned first current values, each first current value is used for electrochemical-three-dimensional thermal model charging simulation to obtain the minimum negative electrode potential of the above-mentioned target battery without lithium deposition.

[0032] Step S103, obtaining a charging current boundary value of the target battery according to a target open circuit voltage-state of charge curve and a target negative electrode potential of the target battery, wherein the target open circuit voltage-state of charge curve is obtained by discharging and then charging the target battery.

[0033] Optionally, the target battery is discharged to different SOCs and charged to 100% to obtain the above-mentioned target open circuit voltage-state of charge curve. SOC, State of Charge, is an indicator to measure the remaining power of a battery, usually expressed as a percentage. SOC represents the current state of charge of the battery, that is, the percentage of power in the battery when it is fully charged. The SOC range of the battery is usually 0% (fully discharged) to 100% (fully charged).

[0034] The target open circuit voltage-state of charge curve and the target negative electrode potential of the target battery are used for model simulation to obtain the charging current boundary value of the target battery.

[0035] In summary, the minimum negative electrode potential of the target battery without lithium precipitation is obtained by the maximum current without lithium precipitation at different temperature values, and then the target open circuit voltage-state of charge curve and the target negative electrode potential are obtained by discharging and then charging the target battery, and the charging current boundary value of the target battery is determined. The target open circuit voltage-state of charge curve fully takes into account the influence of voltage hysteresis, and can more accurately evaluate the fast charging performance boundary of the battery in this case, providing a reference for improving the fast charging rate in actual battery applications, thereby achieving the effect of increasing the battery charging rate.

[0036] Optionally, in the method for determining the current boundary of a lithium battery provided in an embodiment of the present application, under a first current value, simulation is performed through a preset electrochemical-three-dimensional thermal model of the target battery to obtain a target negative electrode potential, including: under a first current value, charging simulation is performed through a preset electrochemical-three-dimensional thermal model of the target battery to obtain an initial negative electrode potential; based on the initial negative electrode potential, a plurality of gradient negative electrode potentials are generated; under a plurality of gradient negative electrode potentials, simulation is performed through a preset electrochemical-three-dimensional thermal model of the target battery to obtain a target negative electrode potential.

[0037] In an optional embodiment, the target negative electrode potential is obtained by the following steps: Under the first current value, the electrochemical-three-dimensional thermal model of the target battery is charged and simulated to obtain the corresponding initial negative electrode potential. Then, multiple gradient negative electrode potentials are generated with the initial negative electrode potential as the center. For example, if the initial negative electrode potential is 0mV, the corresponding gradient negative electrode potential may include: -5mV, 0mV, 5mV. Based on the above-mentioned gradient negative electrode potential, the electrochemical-three-dimensional thermal model of the target battery is simulated with a constant negative electrode potential as the control condition to obtain the lowest negative electrode potential U_neg_1 (i.e., the above-mentioned target negative electrode potential) without lithium precipitation.

[0038] By simulating the electrochemical-three-dimensional thermal model through the above-mentioned gradient negative electrode potential, the target negative electrode potential without lithium precipitation can be accurately obtained.

[0039] Optionally, in the method for determining the current boundary of a lithium battery provided in an embodiment of the present application, under multiple gradient negative electrode potentials, simulation is performed through a preset electrochemical-three-dimensional thermal model of the target battery to obtain the target negative electrode potential, including: for each gradient negative electrode potential, at multiple temperature values, simulation calculation is performed through an electrochemical-three-dimensional thermal model to obtain second current values ​​under multiple charge states; charge and discharge cycle treatment is performed on the target battery according to the gradient negative electrode potential and the second current values ​​under multiple charge states to obtain a treated target battery; status information of the treated target battery is obtained, and the target negative electrode potential is determined from the multiple gradient negative electrode potentials based on the status information, wherein the status information is used to characterize whether lithium deposition occurs in the target battery.

[0040] In an optional embodiment, the following steps are used to simulate the electrochemical-three-dimensional thermal model to obtain the above-mentioned target negative electrode potential: for each gradient negative electrode potential, the electrochemical-three-dimensional thermal model is simulated and calculated at multiple temperature values ​​to obtain the second current value of multiple charge states, such as Figure 2 The simulated fast charging current result diagram with the negative electrode potential as the control condition is shown, and the current curve diagram under multiple SOCs.

[0041] Then, the target battery is subjected to charge and discharge cycle treatment by using a gradient negative electrode potential and a second current value at multiple charge states, that is, by Figure 2 The curve graph shown is for charging and discharging the target battery for cycles. In an optional embodiment, the target battery may be charged and discharged for 10 cycles.

[0042] After the target battery charge and discharge cycle is completed, the state of the target battery is detected to determine whether the target battery has lithium deposition. Finally, the target negative electrode potential is determined from multiple gradient negative electrode potentials based on whether the target battery has lithium deposition.

[0043] The second current values ​​under multiple charge states are obtained through electrochemical-three-dimensional thermal model simulation, and then the lowest negative electrode potential U_neg_1 without lithium precipitation is obtained by verification based on the second current value through the target battery, thereby improving the accuracy of the lowest negative electrode potential.

[0044] Optionally, in the method for determining the current boundary of a lithium battery provided in an embodiment of the present application, before simulating the target negative electrode potential through the preset electrochemical-three-dimensional thermal model of the target battery, the method also includes: constructing an electrochemical model based on the chemical reaction parameters of the target battery; constructing a three-dimensional thermal model based on the heat transfer parameters of the target battery; and coupling the electrochemical model and the three-dimensional thermal model to obtain an electrochemical-three-dimensional thermal model.

[0045] In an optional embodiment, the above-mentioned electrochemical-three-dimensional thermal model is obtained by the following steps: the chemical reaction in the internal space of the battery is simplified to a one-dimensional reaction along the thickness direction, and then the above-mentioned electrochemical model is constructed based on the conservation of mass, conservation of charge and electrochemical kinetic equations.

[0046] Then, a three-dimensional thermal model is constructed based on the heat transfer (e.g., heat conduction, heat convection, and heat radiation) and energy conservation equations inside the battery. Finally, the electrochemical model and the three-dimensional thermal model are coupled to ensure that the interaction between the electrochemical model and the thermal model can be correctly described, for example, how the heat energy generated by the electrochemical reaction affects the temperature distribution of the battery, thereby obtaining the above-mentioned electrochemical-three-dimensional thermal model.

[0047] The electrochemical-three-dimensional thermal model can be used to accurately analyze the electrochemical performance and thermal behavior of the battery at different temperatures, thereby improving the accuracy of the subsequent determination of the charging current boundary value.

[0048] Optionally, in the method for determining the current boundary of a lithium battery provided in an embodiment of the present application, before obtaining the charging current boundary value of the target battery based on the target open circuit voltage-state of charge curve and the target negative electrode potential of the target battery, the method also includes: discharging the target battery to multiple states of charge to obtain a target battery in each state of charge; charging the target battery in each state of charge to obtain an open circuit voltage-state of charge curve for each state of charge; and determining the target open circuit voltage-state of charge curve based on the open circuit voltage-state of charge curve for each state of charge.

[0049] In an optional embodiment, the target open circuit voltage-state of charge curve is obtained by the following steps: first, the target battery is discharged to multiple states of charge, for example, the target battery is discharged to 10% SOC, 20% SOC, 30% SOC, etc., and then the target battery at each state of charge is charged to obtain the open circuit voltage-state of charge curve of each state of charge, and finally, the target open circuit voltage-state of charge curve is determined according to the open circuit voltage-state of charge curve of each state of charge. For example, Figure 3The OCV-SOC curves (i.e., the above-mentioned open circuit voltage-state of charge curves) of charging after discharging to different SOCs are shown. The influence of voltage hysteresis can be fully considered through the open circuit voltage-state of charge curves of each state of charge, thereby improving the accuracy of determining the boundary value of the charging current.

[0050] Optionally, in the method for determining the current boundary of a lithium battery provided in an embodiment of the present application, obtaining the charging current boundary value of the target battery based on the target open circuit voltage-state of charge curve and the target negative electrode potential of the target battery includes: transmitting the data corresponding to the target open circuit voltage-state of charge curve to an electrochemical-three-dimensional thermal model; performing charging simulation processing on the electrochemical-three-dimensional thermal model with the target negative electrode potential as a control condition to obtain the maximum charging current value; and obtaining the charging current boundary value of the target battery based on the maximum charging current value.

[0051] In an optional embodiment, data corresponding to the target open circuit voltage-state of charge curve is transmitted to the electrochemical-three-dimensional thermal model, and the electrochemical-three-dimensional thermal model is charged and simulated with the U_neg_1 control condition to obtain the maximum charging current value MAP, and then the fast charging non-lithium deposition boundary current (i.e., the above-mentioned charging current boundary value) under the corresponding temperature conditions after discharging to different SOCs is obtained based on the maximum charging current value MAP.

[0052] For example, Figure 4 As shown in the figure, taking the working condition after discharging to 20% SOC as an example, the simulation results are respectively the model adjusted by 0-100% SOC OCV-SOC and the model adjusted by 20-100% SOC OCV-SOC after discharging to 20% SOC. Both use the same negative electrode potential as the control condition to determine the maximum current fast charge MAP without lithium precipitation, and the charging current of 25°C and 20-100% is measured according to MAP. It can be seen that the evaluation current considering the voltage hysteresis effect is larger than that without considering the voltage hysteresis, which can give full play to the battery capacity.

[0053] Optionally, in the method for determining the current boundary of a lithium battery provided in an embodiment of the present application, obtaining a first current value corresponding to a target battery at multiple temperature values ​​includes: determining multiple temperature values ​​based on the operating conditions of the target battery; charging the target battery at each temperature value; and obtaining a first current value during the charging process of the target battery.

[0054] In an optional embodiment, the first current value mentioned above is obtained by the following steps: a plurality of temperature values ​​are determined according to the working conditions of the target battery, and then the target battery is charged at each temperature value, so as to obtain the maximum current value of the target battery without lithium deposition, that is, to obtain the first current value mentioned above.

[0055] In an optional embodiment, the Figure 5 The flowchart shown realizes the determination of the charging current boundary value of the target battery, which specifically includes the following steps: establishing a one-dimensional electrochemical-three-dimensional thermal model based on the target lithium-ion battery; setting a temperature gradient to test the maximum current that prevents lithium precipitation in the target battery; using the current for model simulation to obtain the corresponding negative electrode potential U_neg_0; under isothermal conditions, selecting a typical temperature, setting a negative electrode potential gradient based on U_neg_0, and calculating the corresponding current with a constant negative electrode potential as the control condition, and verifying the minimum negative electrode potential U_neg_1 without lithium precipitation by actual measurement; under temperature T conditions, testing the OCV-SOC of charging after discharging to different SOCs (10 / 20 / 30%...) considering voltage hysteresis; importing OCV-SOC data for adjusting the model, and determining the maximum charging current MAP under different temperatures and SOCs with U_neg_1 as the control condition; based on the fast charging current MAP, using temperature and SOC to control the current, and obtaining the non-lithium precipitation boundary current of fast charging under certain temperature conditions after discharging to different SOCs.

[0056] Optionally, in the method for determining the current boundary of a lithium battery provided in an embodiment of the present application, the electrochemical model and the three-dimensional thermal model are coupled to obtain an electrochemical-three-dimensional thermal model, which includes: coupling the electrochemical model and the three-dimensional thermal model to obtain an initial electrochemical-three-dimensional thermal model; simulating and verifying the initial electrochemical-three-dimensional thermal model to obtain a verification result; and optimizing and adjusting the initial electrochemical-three-dimensional thermal model based on the verification result to obtain an electrochemical-three-dimensional thermal model.

[0057] In an optional embodiment, coupling the electrochemical model and the three-dimensional thermal model to obtain the electrochemical-three-dimensional thermal model includes the following steps: coupling the electrochemical model and the three-dimensional thermal model to obtain an initial electrochemical-three-dimensional thermal model. In order to improve the accuracy of the initial electrochemical-three-dimensional thermal model for the electrochemical performance and thermal behavior of the battery at different temperatures, the initial electrochemical-three-dimensional thermal model is simulated and verified, and the initial electrochemical-three-dimensional thermal model is optimized and adjusted based on the verification results, thereby obtaining the above-mentioned electrochemical-three-dimensional thermal model.

[0058] The method for determining the current boundary of a lithium battery provided in an embodiment of the present application obtains a first current value corresponding to a target battery at multiple temperature values, wherein the first current value is the maximum current value of the target battery without lithium precipitation; under the first current value, a preset electrochemical-three-dimensional thermal model of the target battery is used to simulate to obtain a target negative electrode potential, wherein the target negative electrode potential is the minimum negative electrode potential of the target battery without lithium precipitation; based on a target open circuit voltage-state of charge curve and a target negative electrode potential of the target battery, a charging current boundary value of the target battery is obtained, wherein the target open circuit voltage-state of charge curve is obtained by discharging and then charging the target battery, thereby solving the problem in the related art that the fast charging performance boundary of charging after discharging cannot be determined. In this scheme, the minimum negative electrode potential of the target battery without lithium precipitation is obtained by the maximum current without lithium precipitation at different temperature values, and then the target open circuit voltage-state of charge curve and the target negative electrode potential are obtained by discharging and then charging the target battery to determine the charging current boundary value of the target battery. The target open circuit voltage-state of charge curve fully takes into account the influence of voltage hysteresis, and can more accurately evaluate the fast charging performance boundary of the battery in this case, providing a reference for improving the fast charging rate in actual battery applications, thereby achieving the effect of increasing the battery charging rate.

[0059] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0060] The embodiment of the present application also provides a device for determining the current boundary of a lithium battery. It should be noted that the device for determining the current boundary of a lithium battery in the embodiment of the present application can be used to execute the method for determining the current boundary of a lithium battery provided in the embodiment of the present application. The device for determining the current boundary of a lithium battery provided in the embodiment of the present application is introduced below.

[0061] Figure 6 Schematic diagram of a device for determining a current boundary of a lithium battery according to an embodiment of the present application. Figure 6 As shown, the device includes: an acquisition unit 601, a simulation unit 602 and a first determination unit 603.

[0062] An acquisition unit 601 is used to acquire a first current value corresponding to a target battery at multiple temperature values, wherein the first current value is a maximum current value of the target battery without lithium deposition;

[0063] The simulation unit 602 is used to simulate the target negative electrode potential by using the preset electrochemical-three-dimensional thermal model of the target battery under the condition of the first current value, wherein the target negative electrode potential is the minimum negative electrode potential of the target battery without lithium precipitation;

[0064] The first determination unit 603 is used to obtain a charging current boundary value of the target battery according to a target open circuit voltage-state of charge curve and a target negative electrode potential of the target battery, wherein the target open circuit voltage-state of charge curve is obtained by discharging and then charging the target battery.

[0065] The device for determining the current boundary of a lithium battery provided in an embodiment of the present application obtains a first current value corresponding to a target battery at multiple temperature values ​​through an acquisition unit 601, wherein the first current value is the maximum current value of the target battery without lithium precipitation; the simulation unit 602 performs simulation through a preset electrochemical-three-dimensional thermal model of the target battery under the condition of the first current value to obtain a target negative electrode potential, wherein the target negative electrode potential is the minimum negative electrode potential of the target battery without lithium precipitation; the first determination unit 603 obtains a charging current boundary value of the target battery based on a target open circuit voltage-state of charge curve and a target negative electrode potential of the target battery, wherein the target open circuit voltage-state of charge curve is obtained by discharging and then charging the target battery, thereby solving the problem in the related art that the fast charging performance boundary of charging after discharging cannot be determined. In this scheme, the minimum negative electrode potential of the target battery without lithium precipitation is obtained by the maximum current without lithium precipitation at different temperature values, and then the target open circuit voltage-state of charge curve and the target negative electrode potential are obtained by discharging and then charging the target battery to determine the charging current boundary value of the target battery. The target open circuit voltage-state of charge curve fully takes into account the influence of voltage hysteresis, and can more accurately evaluate the fast charging performance boundary of the battery in this case, providing a reference for improving the fast charging rate in actual battery applications, thereby achieving the effect of increasing the battery charging rate.

[0066] Optionally, in the device for determining the current boundary of a lithium battery provided in an embodiment of the present application, the simulation unit includes: a first simulation module, which is used to perform charging simulation under a first current value through a preset electrochemical-three-dimensional thermal model of a target battery to obtain an initial negative electrode potential; a generation module, which is used to generate a plurality of gradient negative electrode potentials based on the initial negative electrode potential; and a second simulation module, which is used to perform simulation under a plurality of gradient negative electrode potentials through a preset electrochemical-three-dimensional thermal model of a target battery to obtain a target negative electrode potential.

[0067] Optionally, in the device for determining the current boundary of a lithium battery provided in an embodiment of the present application, the second simulation module includes: a calculation submodule, which is used to perform simulation calculations through an electrochemical-three-dimensional thermal model at multiple temperature values ​​for each gradient negative electrode potential to obtain second current values ​​under multiple charge states; a processing submodule, which is used to perform charge and discharge cycle processing on the target battery according to the gradient negative electrode potential and the second current values ​​under multiple charge states to obtain a processed target battery; a determination submodule, which is used to obtain status information of the processed target battery, and determine the target negative electrode potential from multiple gradient negative electrode potentials based on the status information, wherein the status information is used to characterize whether lithium plating occurs in the target battery.

[0068] Optionally, in the device for determining the current boundary of a lithium battery provided in an embodiment of the present application, the device also includes: a first construction unit, used to construct an electrochemical model based on the chemical reaction parameters of the target battery before simulating the preset electrochemical-three-dimensional thermal model of the target battery to obtain the target negative electrode potential; a second construction unit, used to construct a three-dimensional thermal model based on the heat transfer parameters of the target battery; and a coupling unit, used to couple the electrochemical model and the three-dimensional thermal model to obtain an electrochemical-three-dimensional thermal model.

[0069] Optionally, in the device for determining the current boundary of a lithium battery provided in an embodiment of the present application, the device also includes: a discharging unit, used to discharge the target battery to multiple charge states before obtaining the charging current boundary value of the target battery based on the target open circuit voltage-state of charge curve and the target negative electrode potential of the target battery, so as to obtain the target battery in each charge state; a charging unit, used to charge the target battery in each charge state to obtain the open circuit voltage-state of charge curve of each charge state; and a second determination unit, used to determine the target open circuit voltage-state of charge curve based on the open circuit voltage-state of charge curve of each charge state.

[0070] Optionally, in the device for determining the current boundary of a lithium battery provided in an embodiment of the present application, a first determination unit includes: a transmission module, used to transmit data corresponding to the target open circuit voltage-state of charge curve to an electrochemical-three-dimensional thermal model; a third simulation module, used to perform charging simulation processing on the electrochemical-three-dimensional thermal model with the target negative electrode potential as a control condition to obtain a maximum charging current value; and a first determination module, used to obtain a charging current boundary value of a target battery based on the maximum charging current value.

[0071] Optionally, in the device for determining the current boundary of a lithium battery provided in an embodiment of the present application, an acquisition unit includes: a second determination module, used to determine multiple temperature values ​​based on the working conditions of the target battery; a charging module, used to charge the target battery at each temperature value; and an acquisition module, used to acquire a first current value during the charging process of the target battery.

[0072] The device for determining the current boundary of a lithium battery includes a processor and a memory. The above-mentioned acquisition unit 601, simulation unit 602 and first determination unit 603 are all stored in the memory as program units, and the processor executes the above-mentioned program units stored in the memory to implement corresponding functions.

[0073] The processor includes a kernel, which calls the corresponding program unit from the memory. One or more kernels can be set to determine the charging current boundary of the lithium battery by adjusting the kernel parameters.

[0074] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0075] An embodiment of the present invention provides a computer-readable storage medium having a program stored thereon, and when the program is executed by a processor, a method for determining a current boundary of a lithium battery is implemented.

[0076] An embodiment of the present invention provides a processor, which is used to run a program, wherein the program executes a method for determining a current boundary of a lithium battery when the program is running.

[0077] like Figure 7 As shown, an embodiment of the present invention provides an electronic device, the device includes a processor, a memory, and a program stored in the memory and executable on the processor, and the processor implements the following steps when executing the program: obtaining a first current value corresponding to a target battery at multiple temperature values, wherein the first current value is a maximum current value of the target battery without lithium precipitation; under the first current value, simulating through a preset electrochemical-three-dimensional thermal model of the target battery to obtain a target negative electrode potential, wherein the target negative electrode potential is a minimum negative electrode potential of the target battery without lithium precipitation; obtaining a charging current boundary value of the target battery based on a target open circuit voltage-state of charge curve and a target negative electrode potential of the target battery, wherein the target open circuit voltage-state of charge curve is obtained by discharging and then charging the target battery.

[0078] Optionally, under the condition of a first current value, simulation is performed through a preset electrochemical-three-dimensional thermal model of the target battery to obtain a target negative electrode potential, including: under the condition of a first current value, charging simulation is performed through a preset electrochemical-three-dimensional thermal model of the target battery to obtain an initial negative electrode potential; based on the initial negative electrode potential, a plurality of gradient negative electrode potentials are generated; under a plurality of gradient negative electrode potentials, simulation is performed through a preset electrochemical-three-dimensional thermal model of the target battery to obtain a target negative electrode potential.

[0079] Optionally, under multiple gradient negative electrode potentials, simulation is performed through a preset electrochemical-three-dimensional thermal model of the target battery to obtain the target negative electrode potential, including: for each gradient negative electrode potential, at multiple temperature values, simulation calculation is performed through the electrochemical-three-dimensional thermal model to obtain second current values ​​under multiple charge states; charge and discharge cycle treatment is performed on the target battery according to the gradient negative electrode potential and the second current values ​​under multiple charge states to obtain a treated target battery; state information of the treated target battery is obtained, and the target negative electrode potential is determined from the multiple gradient negative electrode potentials based on the state information, wherein the state information is used to characterize whether lithium deposition occurs in the target battery.

[0080] Optionally, before simulating the preset electrochemical-three-dimensional thermal model of the target battery to obtain the target negative electrode potential, the method also includes: constructing an electrochemical model based on the chemical reaction parameters of the target battery; constructing a three-dimensional thermal model based on the heat transfer parameters of the target battery; and coupling the electrochemical model and the three-dimensional thermal model to obtain an electrochemical-three-dimensional thermal model.

[0081] Optionally, before obtaining the charging current boundary value of the target battery based on the target open circuit voltage-state of charge curve and the target negative electrode potential of the target battery, the method also includes: discharging the target battery to multiple states of charge to obtain the target battery in each state of charge; charging the target battery in each state of charge to obtain the open circuit voltage-state of charge curve of each state of charge; and determining the target open circuit voltage-state of charge curve based on the open circuit voltage-state of charge curve of each state of charge.

[0082] Optionally, obtaining the charging current boundary value of the target battery based on the target open circuit voltage-state of charge curve and the target negative electrode potential of the target battery includes: transmitting data corresponding to the target open circuit voltage-state of charge curve to the electrochemical-three-dimensional thermal model; performing charging simulation processing on the electrochemical-three-dimensional thermal model with the target negative electrode potential as the control condition to obtain the maximum charging current value; and obtaining the charging current boundary value of the target battery based on the maximum charging current value.

[0083] Optionally, obtaining a first current value corresponding to a target battery at multiple temperature values ​​includes: determining multiple temperature values ​​according to an operating condition of the target battery; charging the target battery at each temperature value; and obtaining the first current value during the charging process of the target battery.

[0084] Optionally, coupling the electrochemical model and the three-dimensional thermal model to obtain an electrochemical-three-dimensional thermal model includes: coupling the electrochemical model and the three-dimensional thermal model to obtain an initial electrochemical-three-dimensional thermal model; simulating and verifying the initial electrochemical-three-dimensional thermal model to obtain a verification result; and optimizing and adjusting the initial electrochemical-three-dimensional thermal model based on the verification result to obtain an electrochemical-three-dimensional thermal model.

[0085] The devices in this article can be servers, PCs, PADs, mobile phones, etc.

[0086] The present application also provides a computer program product, which, when executed on a data processing device, is suitable for executing a program that initializes the following method steps: obtaining a first current value corresponding to a target battery at multiple temperature values, wherein the first current value is the maximum current value of the target battery without lithium precipitation; under the first current value, simulating through a preset electrochemical-three-dimensional thermal model of the target battery to obtain a target negative electrode potential, wherein the target negative electrode potential is the minimum negative electrode potential of the target battery without lithium precipitation; obtaining a charging current boundary value of the target battery based on a target open circuit voltage-state of charge curve and a target negative electrode potential of the target battery, wherein the target open circuit voltage-state of charge curve is obtained by discharging and then charging the target battery.

[0087] Optionally, under the condition of a first current value, simulation is performed through a preset electrochemical-three-dimensional thermal model of the target battery to obtain a target negative electrode potential, including: under the condition of a first current value, charging simulation is performed through a preset electrochemical-three-dimensional thermal model of the target battery to obtain an initial negative electrode potential; based on the initial negative electrode potential, a plurality of gradient negative electrode potentials are generated; under a plurality of gradient negative electrode potentials, simulation is performed through a preset electrochemical-three-dimensional thermal model of the target battery to obtain a target negative electrode potential.

[0088] Optionally, under multiple gradient negative electrode potentials, simulation is performed through a preset electrochemical-three-dimensional thermal model of the target battery to obtain the target negative electrode potential, including: for each gradient negative electrode potential, at multiple temperature values, simulation calculation is performed through the electrochemical-three-dimensional thermal model to obtain second current values ​​under multiple charge states; charge and discharge cycle treatment is performed on the target battery according to the gradient negative electrode potential and the second current values ​​under multiple charge states to obtain a treated target battery; state information of the treated target battery is obtained, and the target negative electrode potential is determined from the multiple gradient negative electrode potentials based on the state information, wherein the state information is used to characterize whether lithium deposition occurs in the target battery.

[0089] Optionally, before simulating the target negative electrode potential through the preset electrochemical-three-dimensional thermal model of the target battery, the method also includes: constructing an electrochemical model based on the chemical reaction parameters of the target battery; constructing a three-dimensional thermal model based on the heat transfer parameters of the target battery; and coupling the electrochemical model and the three-dimensional thermal model to obtain an electrochemical-three-dimensional thermal model.

[0090] Optionally, before obtaining the charging current boundary value of the target battery based on the target open circuit voltage-state of charge curve and the target negative electrode potential of the target battery, the method also includes: discharging the target battery to multiple states of charge to obtain the target battery in each state of charge; charging the target battery in each state of charge to obtain the open circuit voltage-state of charge curve of each state of charge; and determining the target open circuit voltage-state of charge curve based on the open circuit voltage-state of charge curve of each state of charge.

[0091] Optionally, obtaining the charging current boundary value of the target battery based on the target open circuit voltage-state of charge curve and the target negative electrode potential of the target battery includes: transmitting data corresponding to the target open circuit voltage-state of charge curve to the electrochemical-three-dimensional thermal model; performing charging simulation processing on the electrochemical-three-dimensional thermal model with the target negative electrode potential as the control condition to obtain the maximum charging current value; and obtaining the charging current boundary value of the target battery based on the maximum charging current value.

[0092] Optionally, obtaining a first current value corresponding to a target battery at multiple temperature values ​​includes: determining multiple temperature values ​​according to an operating condition of the target battery; charging the target battery at each temperature value; and obtaining the first current value during the charging process of the target battery.

[0093] Optionally, coupling the electrochemical model and the three-dimensional thermal model to obtain an electrochemical-three-dimensional thermal model includes: coupling the electrochemical model and the three-dimensional thermal model to obtain an initial electrochemical-three-dimensional thermal model; simulating and verifying the initial electrochemical-three-dimensional thermal model to obtain a verification result; and optimizing and adjusting the initial electrochemical-three-dimensional thermal model based on the verification result to obtain an electrochemical-three-dimensional thermal model.

[0094] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0095] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0096] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0097] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0098] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0099] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0100] Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.

[0101] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including 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, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0102] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0103] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included within the scope of the claims of the present application.

Claims

1. A method for determining the current boundary of a lithium battery, characterized in that: include: Acquire a first current value corresponding to a target battery at multiple temperature values, wherein the first current value is a maximum current value of the target battery without lithium deposition; Under the first current value, a target negative electrode potential is obtained by simulating a preset electrochemical-three-dimensional thermal model of the target battery, wherein the target negative electrode potential is the minimum negative electrode potential of the target battery without lithium deposition; The charging current boundary value of the target battery is obtained according to the target open circuit voltage-state of charge curve of the target battery and the target negative electrode potential, wherein the target open circuit voltage-state of charge curve is obtained by discharging and then charging the target battery.

2. The method according to claim 1, characterized in that In the case of the first current value, the target negative electrode potential is obtained by simulating the preset electrochemical-three-dimensional thermal model of the target battery, including: Under the first current value, a charging simulation is performed using a preset electrochemical-three-dimensional thermal model of the target battery to obtain an initial negative electrode potential; Generating a plurality of gradient negative electrode potentials according to the initial negative electrode potential; Under the multiple gradient negative electrode potentials, the target negative electrode potential is obtained by performing simulation using a preset electrochemical-three-dimensional thermal model of the target battery.

3. The method according to claim 2, characterized in that Under the multiple gradient negative electrode potentials, the target negative electrode potential is obtained by simulating the preset electrochemical-three-dimensional thermal model of the target battery, including: For each gradient negative electrode potential, at multiple temperature values, a simulation calculation is performed using the electrochemical-three-dimensional thermal model to obtain second current values ​​at multiple charge states; Performing charge-discharge cycle processing on the target battery according to the gradient negative electrode potential and the second current values ​​of the multiple states of charge to obtain a processed target battery; Acquire the state information of the processed target battery, and determine the target negative electrode potential from the multiple gradient negative electrode potentials according to the state information, wherein the state information is used to characterize whether lithium deposition occurs in the target battery.

4. The method according to claim 1, characterized in that: Before simulating the target negative electrode potential by using a preset electrochemical-three-dimensional thermal model of the target battery, the method further includes: Constructing an electrochemical model according to the chemical reaction parameters of the target battery; Constructing a three-dimensional thermal model according to the heat transfer parameters of the target battery; The electrochemical model and the three-dimensional thermal model are coupled to obtain the electrochemical-three-dimensional thermal model.

5. The method according to claim 1, characterized in that Before obtaining the charging current boundary value of the target battery according to the target open circuit voltage-state of charge curve of the target battery and the target negative electrode potential, the method further includes: Discharging the target battery to multiple states of charge to obtain a target battery at each state of charge; Charging the target battery at each state of charge to obtain an open circuit voltage-state of charge curve at each state of charge; The target open circuit voltage-state of charge curve is determined according to the open circuit voltage-state of charge curve of each state of charge.

6. The method according to claim 1, characterized in that Obtaining the charging current boundary value of the target battery according to the target open circuit voltage-state of charge curve of the target battery and the target negative electrode potential includes: Transmitting data corresponding to the target open circuit voltage-state of charge curve to the electrochemical-three-dimensional thermal model; Taking the target negative electrode potential as a control condition, performing charging simulation processing on the electrochemical-three-dimensional thermal model to obtain a maximum charging current value; A charging current boundary value of the target battery is obtained according to the maximum charging current value.

7. The method according to claim 1, characterized in that Obtaining a first current value corresponding to a target battery at multiple temperature values ​​includes: Determining a plurality of temperature values ​​according to the operating condition of the target battery; At each temperature value, charging the target battery; The first current value is obtained during the charging process of the target battery.

8. The method according to claim 4, characterized in that The electrochemical model and the three-dimensional thermal model are coupled to obtain the electrochemical-three-dimensional thermal model, comprising: coupling the electrochemical model and the three-dimensional thermal model to obtain an initial electrochemical-three-dimensional thermal model; Performing simulation verification on the initial electrochemical-three-dimensional thermal model to obtain verification results; The initial electrochemical-three-dimensional thermal model is optimized and adjusted according to the verification result to obtain the electrochemical-three-dimensional thermal model.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a stored program, wherein when the program is executed, the storage medium is controlled to execute the method for determining the current boundary of a lithium battery according to any one of claims 1 to 7 on a device.

10. An electronic device, characterized in that: It includes one or more processors and a memory, wherein the memory is used to store one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors implement the method for determining the current boundary of a lithium battery as described in any one of claims 1 to 7.

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