Battery cell performance parameter prediction method and device and electronic equipment

Abstract

The invention discloses a cell performance parameter prediction method and apparatus, and an electronic device. The method comprises the following steps: obtaining target slurry which is used for constructing a target type of battery cell; corresponding test data of the target slurry under the test parameters are determined, and the test data comprise impedance test data; the impedance test data are input into an equivalent circuit model for fitting, a plurality of circuit parameter values are obtained, and the equivalent circuit model is constructed according to the target type of battery cell; and according to the plurality of circuit parameter values, predicting performance parameters of the battery cell prepared by using the target slurry under the test parameters. According to the invention, the technical problem that it is difficult to determine the performance parameters related to the battery cell according to the slurry conveniently in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the field of batteries, and in particular to a method and device for predicting battery cell performance parameters, and electronic equipment. Background Art

[0002] Lithium-ion batteries are composed of positive electrodes, negative electrodes, and electrolytes, and the conductivity of electrode slurry is an important indicator for evaluating electrode performance. Conductivity refers to the ability of an object to conduct current. The conductivity of each material in the battery is directly related to the battery capacity and rate performance.

[0003] Generally, the conductivity of the electrode slurry is measured to evaluate the conductive properties of the electrode slurry. Currently, for the resistivity test of the conductive slurry of the battery material, China's public patent CN108303592A discloses a method for testing the conductivity of the electrode dressing layer of a lithium-ion battery, and China's public patent CN108226641A discloses a method for testing the conductivity of the positive electrode material of a lithium-ion battery. However, the internal composition of the conductive slurry of the lithium-ion battery electrode is complex. The above-mentioned traditional methods cannot quickly obtain the internal conductive network data, resulting in the inability to determine the composition of the conductive network inside the slurry, and the inability to further screen the type and content of the conductive agent, and the type and content of the main material. This makes the screening of the electrode slurry formula cumbersome and inefficient, and there is a technical problem that it is difficult to conveniently determine the performance parameters related to the battery cell based on the slurry.

[0004] To address the above-mentioned problems, no effective solution has been proposed yet. Summary of the invention

[0005] The embodiments of the present invention provide a method, device and electronic device for predicting performance parameters of a battery cell, so as to at least solve the technical problem in the related art that it is difficult to conveniently determine performance parameters related to the battery cell based on the slurry.

[0006] According to one aspect of an embodiment of the present invention, a method for predicting performance parameters of a battery cell is provided, comprising: obtaining a target slurry, wherein the target slurry is used to construct a battery cell of a target type; determining test data corresponding to the target slurry under test parameters, wherein the test data includes impedance test data; inputting the impedance test data into an equivalent circuit model for fitting to obtain a plurality of circuit parameter values, wherein the equivalent circuit model is constructed based on the battery cell of the target type, and the equivalent circuit model includes four subcircuits, the first subcircuit includes a charge transfer resistor, the second subcircuit is a solution resistor connected in parallel with a first constant phase element, and the third subcircuit is The active material resistor is connected in parallel with the second constant phase element, the fourth sub-circuit is a double layer resistor and capacitor connected in parallel with the third constant phase element, the first constant phase element is a constant phase element representing the interface characteristics between the binder and the solvent, the second constant phase element is a constant phase element representing the interface characteristics between the binder and the active material, the third constant phase element is a constant phase element representing the interface characteristics between the conductive agent and the active material, the double layer resistor and capacitor are obtained by connecting the double layer resistor and the double layer capacitor in series, and the four sub-circuits are connected in series in sequence; based on the multiple circuit parameter values, the performance parameters of the battery cell made using the target slurry under the test parameters are predicted.

[0007] Optionally, predicting the performance parameters of the battery cell made using the target slurry under the test parameters based on the multiple circuit parameter values ​​includes: when the target slurry includes an electrode material, a conductive agent, and a solvent, and the electrode material includes an active substance, and the multiple circuit parameter values ​​include a fitted charge transfer resistance value, a fitted solution resistance value, a fitted active substance resistance value, a fitted double layer resistance value, and a fitted constant phase element value, determining the charge transfer efficiency performance of the solvent and the electrode material based on the fitted charge transfer resistance value; determining the conductive path impedance formed by the binder and the conductive substance based on the fitted solution resistance value; determining the active substance impedance of the active substance inside the electrode material based on the fitted active substance resistance value; determining the charge transfer performance between the conductive agent and the active substance based on the fitted double layer resistance value; determining the dispersion performance of each component inside the target slurry based on the fitted constant phase element value; predicting the performance parameters of the battery cell made using the target slurry under the test parameters based on the charge transfer efficiency performance, the conductive path impedance, the active substance impedance, the charge transfer performance and the dispersion performance.

[0008] Optionally, the method predicts the performance parameters of the battery cell made using the target slurry under the test parameters based on the charge transfer efficiency performance, the conductive path impedance, the active material impedance, the charge transport performance and the dispersion performance, including: when the electrode material also includes a binder, and the fitted constant-phase element value includes a first constant-phase element value, a second constant-phase element value, and a third constant-phase element value, determining a first sub-contact performance between the binder and the solvent based on the first constant-phase element value; determining a second sub-contact performance between the binder and the active material based on the second constant-phase element value; determining a third sub-contact performance between the conductive agent and the active material based on the third constant-phase element value; determining a contact performance corresponding to the electrode material based on the first sub-contact performance, the second sub-contact performance and the third sub-contact performance; predicting the performance parameters of the battery cell made using the target slurry under the test parameters based on the charge transfer efficiency performance, the conductive path impedance, the active material impedance, the charge transport performance, the dispersion performance and the contact performance.

[0009] Optionally, determining the test data corresponding to the target slurry under the test parameters includes: transferring the target slurry to a predetermined test tool, wherein the predetermined test tool includes a target test tube, a first conductive electrode, and a second conductive electrode, the first conductive electrode is located on a first side of the target test tube, and the second conductive electrode is located on a second side of the target test tube; starting the predetermined test tool under the test parameters to obtain the test data.

[0010] Optionally, a frequency band of the AC test current corresponding to the second subcircuit is greater than a frequency band of the AC test current corresponding to the third subcircuit, and a frequency band of the AC test current corresponding to the third subcircuit is greater than a frequency band of the AC test current corresponding to the fourth subcircuit.

[0011] Optionally, after predicting the performance parameters of the battery cell made using the target slurry under the test parameters based on the multiple circuit parameter values, the method further includes: determining the composition parameters of the target slurry when the performance parameters are less than a predetermined threshold; adjusting the composition parameters to obtain an updated slurry to determine the performance parameters corresponding to the updated slurry.

[0012] Optionally, before inputting the impedance test data into an equivalent circuit model for fitting to obtain multiple circuit parameter values, it also includes: obtaining a sample slurry and a sample battery constructed from the sample slurry, wherein the sample battery is a battery of the target type; determining sample performance parameters of the sample battery; determining a comparison relationship between the composition of the sample slurry and the sample performance parameters; and constructing the equivalent circuit model based on the comparison relationship.

[0013] According to one aspect of an embodiment of the present invention, a device for predicting performance parameters of a battery cell is provided, comprising: an acquisition module for acquiring a target slurry, wherein the target slurry is used to construct a battery cell of a target type; a determination module for determining test data corresponding to the target slurry under test parameters, wherein the test data includes impedance test data; a fitting module for inputting the impedance test data into an equivalent circuit model for fitting to obtain a plurality of circuit parameter values, wherein the equivalent circuit model is constructed based on the battery cell of the target type, and the equivalent circuit model includes four sub-circuits, the first sub-circuit includes a charge transfer resistor, the second sub-circuit is a solution resistor connected in parallel with a first constant phase element, , the third sub-circuit is an active material resistor connected in parallel with a second constant phase element, the fourth sub-circuit is a double-layer resistor and capacitor connected in parallel with a third constant phase element, the first constant phase element is a constant phase element representing the interface characteristics between a binder and a solvent, the second constant phase element is a constant phase element representing the interface characteristics between a binder and an active material, the third constant phase element is a constant phase element representing the interface characteristics between a conductive agent and an active material, the double-layer resistor and capacitor are obtained by connecting a double-layer resistor and a double-layer capacitor in series, and the four sub-circuits are connected in series in sequence; a prediction module is used to predict the performance parameters of a battery cell made using the target slurry under the test parameters based on the multiple circuit parameter values.

[0014] According to one aspect of an embodiment of the present invention, there is provided an electronic device, comprising: a processor; and a memory for storing instructions executable by the processor; wherein the processor is configured to execute the instructions to implement any of the above-mentioned methods for predicting battery cell performance parameters.

[0015] According to one aspect of an embodiment of the present invention, a computer-readable storage medium is provided. When instructions in the computer-readable storage medium are executed by a processor of an electronic device, the electronic device is enabled to execute any of the above-mentioned methods for predicting battery cell performance parameters.

[0016] In an embodiment of the present invention, a target slurry is obtained, wherein the target slurry is used to construct a target type of battery cell. The test data corresponding to the target slurry under the test parameters is determined, wherein the test data includes impedance test data. The impedance test data is input into the equivalent circuit model for fitting to obtain multiple circuit parameter values, wherein the equivalent circuit model is constructed according to the target type of battery cell, and the equivalent circuit model includes four subcircuits, the first subcircuit includes a charge transfer resistance, the second subcircuit is a solution resistance in parallel with a first constant phase element, the third subcircuit is an active material resistance in parallel with a second constant phase element, and the fourth subcircuit is a double electric layer resistance and capacitance in parallel with a third constant phase element, the first constant phase element is a constant phase element representing the interface characteristics between the binder and the solvent, the second constant phase element is a constant phase element representing the interface characteristics between the binder and the active material material, the third constant phase element is a constant phase element representing the interface characteristics between the conductive agent and the active material material, and the double electric layer resistance and capacitance are obtained by connecting the double electric layer resistance and the double electric layer capacitance in series, and the four subcircuits are connected in series in sequence. According to multiple circuit parameter values, the performance parameters of the battery cell made using the target slurry under the test parameters are predicted. Since it determines the test data corresponding to the target slurry under the test parameters, and inputs the impedance test data into the equivalent circuit model for fitting, multiple circuit parameter values ​​are obtained. By fitting the circuit parameter values, the performance parameters of the battery cell are predicted, thereby solving the technical problem in the related technology that it is difficult to conveniently determine the performance parameters related to the battery cell based on the slurry. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0018] Figure 1 is a flow chart of a method for predicting battery cell performance parameters according to an embodiment of the present invention.

[0019] Figure 2 It is a schematic diagram of a test tool provided in an optional embodiment of the present invention.

[0020] Figure 3 It is a schematic diagram of a slurry internal impedance fitting circuit provided in an optional embodiment of the present invention.

[0021] Figure 4 It is a comparison chart of slurry impedance data with different conductive agent contents provided in an optional embodiment of the present invention.

[0022] Figure 5 It is the slurry internal impedance fitting data provided by an optional embodiment of the present invention.

[0023] Figure 64 is a structural block diagram of a device for predicting performance parameters of a battery cell according to an embodiment of the present invention. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

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

[0026] Example 1

[0027] According to an embodiment of the present invention, an embodiment of a method for predicting battery cell performance parameters is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0028] Figure 1 is a flow chart of a method for predicting cell performance parameters according to an embodiment of the present invention. Figure 1 As shown, the method comprises the following steps:

[0029] Step S102, obtaining a target slurry, wherein the target slurry is used to construct a target type of battery cell;

[0030] In step S102 provided in the present application, a target slurry for constructing a target type of battery cell is obtained.

[0031] Among them, the target slurry is involved. In the manufacture of lithium-ion batteries, electrode slurry is a fluid material prepared by mixing electrode active materials (main materials, such as lithium cobalt oxide, lithium iron phosphate, etc.), conductive agents, binders and other components with solvents. Target slurry refers to electrode slurry that is carefully formulated according to specific battery performance requirements or design standards. The formula, component ratio, preparation process, etc. of this slurry are optimized to meet the specific performance indicators of the target battery cell, such as increasing energy density, improving cycle stability, and increasing power output.

[0032] Among them, the target type of battery cell is involved, which refers to a battery cell designed for a specific application and with specific performance parameters, such as a high energy density battery cell for electric vehicles or a high cycle life battery cell for energy storage systems.

[0033] By obtaining a target slurry, it means that a slurry formula has been designed. This slurry will be used to build a target type of battery cell, that is, through a series of manufacturing processes, the slurry is transformed into a battery cell that meets the design standards.

[0034] Step S104, determining test data corresponding to the target slurry under the test parameters, wherein the test data includes impedance test data;

[0035] In step S104 provided in the present application, test data corresponding to the target slurry under test parameters is determined.

[0036] Among them, test parameters are involved. Test parameters refer to the conditions set during the test, including but not limited to temperature, frequency, disturbance voltage, test environment, etc. In electrochemical impedance testing, these parameters are crucial to the accuracy and reliability of the results. For example, the range of test frequency will affect the detection sensitivity of different parts of the slurry impedance (such as charge transfer resistance, diffusion resistance, etc.).

[0037] Among them, test data is involved, which is the result obtained through experimental measurement and contains key information about the performance of the target slurry. In this application, test data mainly refers to impedance test data, including information such as resistance (R), capacitance (C), inductance (L) and impedance phase angle.

[0038] In this step, the test data corresponding to the target slurry under the test parameters is determined, which means that after setting specific test conditions (such as temperature, frequency range, etc.), the target slurry is subjected to impedance testing, and the impedance test data are collected and recorded. These data will reflect the electrochemical properties of the slurry under given conditions, including the integrity of the internal conductive network, the resistance to charge transfer in the slurry, and the interaction between the slurry and the test electrode.

[0039] Step S106, input the impedance test data into the equivalent circuit model for fitting, and obtain multiple circuit parameter values, wherein the equivalent circuit model is constructed according to the target type of battery cell, and the equivalent circuit model includes four sub-circuits, the first sub-circuit includes a charge transfer resistance, the second sub-circuit is a solution resistance connected in parallel with a first constant phase element, the third sub-circuit is an active material resistance connected in parallel with a second constant phase element, and the fourth sub-circuit is a double-layer resistance and capacitance connected in parallel with a third constant phase element, the first constant phase element is a constant phase element representing the interface characteristics between the binder and the solvent, the second constant phase element is a constant phase element representing the interface characteristics between the binder and the active material, the third constant phase element is a constant phase element representing the interface characteristics between the conductive agent and the active material, the double-layer resistance and capacitance are obtained by connecting the double-layer resistance and the double-layer capacitance in series, and the four sub-circuits are connected in series in sequence;

[0040] In step S106 provided in the present application, the impedance test data is input into the equivalent circuit model for fitting, and a plurality of circuit parameter values ​​are obtained.

[0041] Among them, the equivalent circuit model is involved. In electrochemical impedance spectroscopy (EIS) analysis, the equivalent circuit model is a method of simulating the impedance characteristics of an electrochemical cell or slurry using electronic circuit elements (such as resistors, capacitors, and inductors). By adjusting the parameters of the elements in the model, the output impedance of the model matches the actual measured impedance.

[0042] Among them, the charge transfer resistance is involved: it represents the resistance encountered when the charge moves inside the electrode slurry, which is usually related to the dispersion of the conductive agent and the active material.

[0043] Among them, solution resistance is involved. Inside the battery, the migration of ions in the electrolyte will also encounter resistance, which is called solution resistance. It is usually related to the type and concentration of the electrolyte and the operating temperature of the battery.

[0044] Among them, the first / second / third constant phase elements are involved. The constant phase element is an element used to simulate the behavior of a non-ideal capacitor or a combination of a capacitor and a resistor in parallel. In the equivalent circuit model of the battery slurry, the first constant phase element simulates the interface characteristics between the binder and the solvent, the second constant phase element simulates the interface characteristics between the binder and the active material, and the third constant phase element simulates the interface characteristics between the conductive agent and the active material.

[0045] Among them, double-layer resistance and capacitance are involved. The double layer refers to the electrochemical layer formed between the electrode surface and the electrolyte interface. It is composed of tightly adsorbed charges and countercharges to form a capacitor. The double-layer resistance and capacitance (part of the Randles circuit) includes a combination of double-layer resistance (Rdl) and double-layer capacitance (Cdl) to simulate the electrochemical behavior of the electrode / electrolyte interface.

[0046] Among them, multiple circuit parameter values ​​are involved: in electrochemical impedance spectroscopy (EIS) analysis, after the equivalent circuit model is fitted to the impedance test data, a series of circuit parameter values ​​will be obtained, for example, charge transfer resistance (Rct), solution resistance (Rs), active material resistance (Ractive), double layer resistance (Rdl), constant phase element (CPE) parameters, etc. These parameter values ​​reflect the electrochemical processes such as charge transfer inside the electrode slurry, solution conductivity, electrochemical reaction of active materials and material interface characteristics.

[0047] By inputting the impedance test data into an equivalent circuit model for fitting, multiple circuit parameter values ​​can be obtained. The parameter values ​​obtained during the fitting process can reveal the interaction between the components in the slurry and how they affect the conductivity and electrochemical stability of the electrode. And based on the analysis of the equivalent circuit model, it can guide the selection of battery materials and the optimization of slurry formulation to improve the efficiency and reliability of the battery.

[0048] Step S108 , predicting the performance parameters of a battery cell made of the target slurry under the test parameters according to the multiple circuit parameter values.

[0049] In step S108 provided in the present application, the performance parameters of the battery cell made using the target slurry under the test parameters are predicted based on multiple circuit parameter values.

[0050] Among them, the performance parameters of the battery cell are involved. The battery cell is the basic unit of the battery, and its performance parameters include energy density, power density, cycle life, impedance, charge / discharge efficiency, temperature stability and safety, etc. These parameters directly determine the comprehensive performance and application range of the battery.

[0051] In this step, the obtained multiple circuit parameter values ​​are input into the equivalent circuit model based on the target slurry characteristics, and the performance parameters of the battery cell made using the slurry under the set test parameters can be predicted. Based on the analysis of the circuit parameter values, more suitable slurry components and proportions can be screened, such as selecting a more efficient conductive agent, optimizing the type and content of active materials, to achieve ideal battery cell performance.

[0052] Through the above steps S102-S108, the target slurry is obtained, wherein the target slurry is used to construct the target type of battery. Determine the test data corresponding to the target slurry under the test parameters, wherein the test data includes impedance test data. The impedance test data is input into the equivalent circuit model for fitting to obtain multiple circuit parameter values, wherein the equivalent circuit model is constructed according to the target type of battery, and the equivalent circuit model includes four subcircuits, the first subcircuit includes a charge transfer resistance, the second subcircuit is a solution resistance in parallel with a first constant phase element, the third subcircuit is an active material resistance in parallel with a second constant phase element, and the fourth subcircuit is a double electric layer resistance and capacitance in parallel with a third constant phase element, the first constant phase element is a constant phase element representing the interface characteristics between the binder and the solvent, the second constant phase element is a constant phase element representing the interface characteristics between the binder and the active material material, the third constant phase element is a constant phase element representing the interface characteristics between the conductive agent and the active material material, and the double electric layer resistance and capacitance are obtained by connecting the double electric layer resistance and the double electric layer capacitance in series, and the four subcircuits are connected in series in sequence. Based on multiple circuit parameter values, the performance parameters of the battery cell made with the target slurry under the test parameters are predicted. Since the test data corresponding to the target slurry under the test parameters is determined, the impedance test data is input into the equivalent circuit model for fitting to obtain multiple circuit parameter values. By fitting the circuit parameter values, the performance parameters of the battery cell are predicted, thereby solving the technical problem in the related art that it is difficult to conveniently determine the performance parameters related to the battery cell based on the slurry.

[0053] As an optional embodiment, based on multiple circuit parameter values, the performance parameters of the battery cell made using the target slurry under the test parameters are predicted, including: when the target slurry includes an electrode material, a conductive agent, and a solvent, and the electrode material includes an active substance, and the multiple circuit parameter values ​​include a fitted charge transfer resistance value Rs, a fitted solution resistance value Rso, a fitted active substance resistance value Rp, a fitted double layer resistance value Rdl, and a fitted constant phase element value CPE, based on the fitted charge transfer resistance value Rs, the charge transfer efficiency performance of the solvent and the electrode material is determined; based on the fitted solution resistance value Rso, the conductive path impedance formed by the binder and the conductive substance is determined; based on the fitted active substance resistance value Rp, the active substance impedance of the active substance inside the electrode material is determined; based on the fitted double layer resistance value Rdl, the charge transfer performance between the conductive agent and the active substance is determined; based on the fitted constant phase element value CPE, the dispersion performance of each component inside the target slurry is determined; based on the charge transfer efficiency performance, conductive path impedance, active substance impedance, charge transfer performance and dispersion performance, the performance parameters of the battery cell made using the target slurry under the test parameters are predicted.

[0054] In this example, the steps of predicting the performance parameters of a battery cell made using a target slurry under test parameters are described.

[0055] Among them, electrode materials are involved, which include active substances and conductive agents. The active substances are responsible for the energy storage and conversion of the battery, while the conductive agents improve the efficiency of electron transmission inside the electrode.

[0056] Among them, conductive agents are involved: such as carbon nanotubes, graphene, conductive carbon black, etc., which are used to enhance the electronic conductivity inside the electrode and between the electrode and the current collector.

[0057] Among them, solvents are involved: liquid media used to prepare electrode slurry, such as N-methylpyrrolidone, water, ethanol, etc. Appropriate solvents are selected according to different battery types.

[0058] Among them, the fitted charge transfer resistance value Rs is involved: it reflects the resistance to charge movement inside the electrode material and at the interface, and is directly related to the charge transfer efficiency of the battery.

[0059] Among them, it involves fitting the solution resistance value Rso: it represents the resistance to ion migration in the electrolyte and determines the impedance of the conductive path formed by the binder and the conductive material.

[0060] Among them, it involves fitting the active material resistance value Rp: it represents the charge transfer resistance of the active material itself, and can determine the active material impedance of the active material inside the electrode material.

[0061] Among them, it involves fitting the double layer resistance value Rdl: simulating the charge resistance at the contact interface between the conductive agent and the active material, and evaluating the charge transfer performance.

[0062] Among them, the fitting constant phase element value CPE is involved: it is used to describe the behavior of non-ideal capacitors or parallel combinations of capacitors and resistors, and reflects the dispersion properties between materials, including the dispersion properties of interfaces such as binders and active substances, solvents and active substances.

[0063] When the target slurry contains electrode materials, conductive agents and solvents, and the equivalent circuit model successfully fits the values ​​of charge transfer resistance Rs, solution resistance Rso, active material resistance Rp, double layer resistance Rdl and constant phase element CPE, these parameters can correspond to different electrochemical processes inside the electrode slurry. By analyzing these circuit parameters, we can deeply understand the electrochemical behavior inside the slurry, and then predict the performance parameters of the battery cells made with the target slurry under the set test parameters (such as temperature, frequency range, etc.), such as energy density, power density, cycle life, impedance characteristics, etc. Through parameter analysis, the slurry formula can be optimized in a targeted manner, such as adjusting the type and content of the conductive agent to improve the electrochemical performance of the battery.

[0064] As an optional embodiment, based on the charge transfer efficiency performance, conductive path impedance, active material impedance, charge transport performance and dispersion performance, the performance parameters of the battery cell made using the target slurry under the test parameters are predicted, including: when the electrode material also includes a binder, and the fitted constant-phase element value includes a first constant-phase element value, a second constant-phase element value, and a third constant-phase element value, based on the first constant-phase element value CPEs, the first sub-contact performance between the binder and the solvent is determined; based on the second constant-phase element value CPEp, the second sub-contact performance between the binder and the active material is determined; based on the third constant-phase element value CPEdl, the third sub-contact performance between the conductive agent and the active material is determined; based on the first sub-contact performance, the second sub-contact performance and the third sub-contact performance, the contact performance corresponding to the electrode material is determined; based on the charge transfer efficiency performance, conductive path impedance, active material impedance, charge transport performance, dispersion performance and contact performance, the performance parameters of the battery cell made using the target slurry under the test parameters are predicted.

[0065] In this embodiment, the step of determining contact performance to determine performance parameters is described.

[0066] Among them, the constant phase element value CPE is involved. In electrochemical impedance spectroscopy analysis, CPE is used to describe the capacitance characteristics of complex systems, especially when the traditional capacitance model cannot accurately describe the non-ideal interface behavior. The size of the CPE value is related to the roughness and uniformity of the interface and the interaction between the electrode material and the electrolyte or binder.

[0067] Among them, the first constant phase element value CPEs is involved, which reflects the interfacial characteristics between the binder and the solvent and describes the complex capacitive behavior when the two are in contact, including charge distribution, adsorption and desorption processes.

[0068] Among them, the second constant phase element value CPEp is involved, which simulates the interface characteristics between the binder and the active material, especially the contact efficiency between the surface of the active material particles and the binder, which directly affects the mechanical strength of the electrode and the formation of the electronic conductive network.

[0069] Among them, the third constant phase element value CPEdl is involved, which represents the interface characteristics between the conductive agent and the active material, including the coverage of the conductive agent on the surface of the active material, the formation of the conductive network, and the charge transfer efficiency between the two.

[0070] Through the steps provided in this embodiment, the contact performance between materials inside the electrode slurry can also be evaluated hierarchically based on the CPE value obtained by fitting. Combining the first sub-contact performance, the second sub-contact performance and the third sub-contact performance, the internal contact performance of the electrode slurry, that is, the interaction and contact state between the components, can be comprehensively evaluated to better determine the performance parameters of the battery cell. This information plays a key role in understanding the internal structure and electrochemical process of the battery, and then optimizing the slurry formula and battery performance.

[0071] As an optional embodiment, determining the test data corresponding to the target slurry under the test parameters includes: transferring the target slurry to a predetermined test tool, wherein the predetermined test tool includes a target test tube, a first conductive electrode, and a second conductive electrode, the first conductive electrode is located on the first side of the target test tube, and the second conductive electrode is located on the second side of the target test tube; starting the predetermined test tool under the test parameters to obtain the test data.

[0072] In this embodiment, the steps of obtaining test data are described.

[0073] Among them, a predetermined test fixture is involved. The predetermined test fixture is a device specially designed and prepared for electrochemical impedance spectroscopy testing. It includes key components such as a target test tube, a first conductive electrode, and a second conductive electrode, and is used to accurately control the slurry state under test conditions.

[0074] Among them, a target test tube is involved. The target test tube is used to hold slurry. The target test tube can be a visualization test tube. The visualization test tube is a transparent or translucent container that allows an observer to see the state of the internal slurry directly or through an imaging device, including its distribution, contact and reaction, which helps to control the uniformity and content of the slurry.

[0075] Among them, the first conductive electrode and the second conductive electrode are involved. The electrodes in the test tooling are designed to contact the slurry and pass current to obtain electrochemical impedance data. These electrodes are usually made of good conductive materials such as copper, aluminum or gold.

[0076] In this way, in order to obtain the electrochemical impedance test data of the target slurry under specific conditions, the slurry is first transferred to a predetermined test fixture, which includes a target test tube, and a first conductive electrode and a second conductive electrode located on both sides of the test tube, which is also conducive to the fixation of the test tube. In the case where the target test tube is a visual test tube, the visual design allows researchers to intuitively observe the distribution of the slurry between the electrodes, which helps to ensure the uniformity and controllable content of the slurry. Then, the test fixture is started under the set test parameters (such as temperature, frequency range, etc.), and the impedance of the slurry is measured by the electrochemical impedance test system. The final result of this series of operations is to obtain a set of test data, which contains the impedance characteristics of the slurry in different electrochemical processes, such as charge transfer, solution resistance, active material resistance, and double layer resistance.

[0077] Among them, the design of the test fixture can ensure that the slurry maintains structural stability and consistency during the test, which is crucial to the accuracy and repeatability of the impedance test. The fixture can provide a standard environment to ensure the consistency of key parameters such as slurry thickness, contact area and pressure for each test, thereby reducing the variability of the test results and improving the reliability of the data. The conductive electrodes on both sides contained in the test fixture can ensure precise contact with the slurry. Good electrical contact is a prerequisite for obtaining accurate impedance data. If the electrode is in poor contact with the slurry, the impedance value in the test results may be too high, affecting the accurate evaluation of the electrochemical properties of the slurry. The test fixture can be tested within a specific temperature range, which helps to evaluate the impedance performance of the slurry under different temperature conditions, so as to better understand the behavior of the slurry in the actual battery working environment.

[0078] As an optional embodiment, the frequency band of the AC test current corresponding to the second subcircuit is greater than the frequency band of the AC test current corresponding to the third subcircuit, and the frequency band of the AC test current corresponding to the third subcircuit is greater than the frequency band of the AC test current corresponding to the fourth subcircuit.

[0079] In this embodiment, the frequency band of the AC test current is involved. In the electrochemical impedance spectroscopy (EIS) test, an AC signal is used. AC signals of different frequency bands can detect the electrochemical response of samples (such as electrode slurries) on different time scales. High-frequency signals (such as the MHz range) are usually related to fast electrochemical processes such as solution resistance, while low-frequency signals (such as the Hz range) are related to slower electrochemical processes such as charge transfer and diffusion.

[0080] In the electrochemical impedance spectroscopy test, the AC test currents of different frequency bands correspond to different sub-circuits in the circuit model. The frequency band of the AC test current corresponding to the second sub-circuit is higher than that of the third sub-circuit, which means that the second sub-circuit mainly reflects the faster electrochemical process inside the electrode slurry, while the third sub-circuit corresponds to a relatively slow electrochemical process. Similarly, the frequency band of the third sub-circuit is higher than that of the fourth sub-circuit, indicating that the fourth sub-circuit simulates the slowest electrochemical process. This correspondence between the frequency band and the sub-circuit helps to distinguish and identify the time scale of the electrochemical process, thereby more accurately analyzing the electrochemical mechanism in the slurry.

[0081] By using AC test currents of different frequency bands, the fast, medium and slow electrochemical processes inside the slurry can be distinguished. This correspondence enables more accurate allocation and optimization of circuit parameters, such as resistance and capacitance values, when fitting the electrochemical impedance spectrum to reflect the characteristics of different electrochemical processes.

[0082] The processes in electrochemical systems often have different kinetic speeds. Fast processes (such as solution resistance) are usually reflected in high frequency bands, while slow processes (such as charge transfer resistance and diffusion processes) are more significant in low frequency bands. By associating the various components of the equivalent circuit with a specific frequency range, the impedance contribution of different processes in the electrochemical system can be analyzed one by one, thereby obtaining a deeper understanding of the mechanism. Because the impedance characteristics of different components vary at different frequencies. For example, the capacitor component exhibits obvious capacitance characteristics at high frequencies, while the low frequency band may be masked by the characteristics of other impedance components. Therefore, dividing the circuit into multiple orders, each order is optimized and fitted for a specific frequency range, which can improve the accuracy and reliability of the entire impedance spectrum fitting and ensure that each electrochemical process is accurately reflected. By distinguishing these frequency bands, various physical and chemical parameters in the electrochemical system can be more clearly identified and quantified. Understanding the frequency response of different electrochemical processes helps to optimize the performance of battery materials.

[0083] As an optional embodiment, after predicting the performance parameters of a battery cell made using a target slurry under test parameters based on multiple circuit parameter values, it also includes: when the performance parameters are less than a predetermined threshold, determining the composition parameters of the target slurry; adjusting the composition parameters to obtain an updated slurry to determine the performance parameters corresponding to the updated slurry.

[0084] In this embodiment, a process of obtaining a renewed slurry to determine performance parameters corresponding to the renewed slurry is described.

[0085] Among them, the predetermined threshold is involved, which is the minimum or maximum allowable value of a series of parameters set in the battery design stage to achieve the expected battery performance. For example, in order to meet the application requirements of electric vehicles, the energy density threshold of the battery cell may be set above a specific value.

[0086] Among them, composition parameters are involved, which are the material composition and proportion in the electrode slurry, such as the types and contents of active substances, conductive agents, binders, and solvents.

[0087] Among them, it involves updating the slurry, which is the slurry newly prepared after adjusting the composition parameters based on the comparison between the performance prediction results and the predetermined threshold value.

[0088] After predicting the performance parameters of the battery cell made with the target slurry based on the electrochemical impedance spectroscopy test data, if these performance parameters do not reach or fall below the predetermined thresholds set in advance, it is necessary to further analyze the circuit parameter values ​​to determine which composition parameters (such as material type, content or proportion) need to be adjusted. By purposefully changing the composition parameters of the slurry, an updated slurry is prepared and the electrochemical impedance spectroscopy test is performed again. Based on the new test data, the performance parameters of the battery cell are re-predicted until the performance parameters meet or exceed the predetermined thresholds. This process may require multiple iterations until the best slurry formula is found. The feedback loop of electrochemical impedance spectroscopy testing and performance parameter prediction can accelerate the optimization process of the slurry formula, avoiding the time-consuming and resource-wasting traditional test methods. Based on the analysis of the circuit parameter values, the composition parameters of the slurry can be adjusted more accurately to achieve refined control of battery performance.

[0089] As an optional embodiment, before inputting the impedance test data into the equivalent circuit model for fitting to obtain multiple circuit parameter values, it also includes: obtaining a sample slurry, and a sample battery constructed from the sample slurry, wherein the sample battery is a target type of battery; determining sample performance parameters of the sample battery; determining the comparison relationship between the composition of the sample slurry and the sample performance parameters; and constructing an equivalent circuit model based on the comparison relationship.

[0090] In this embodiment, a process of constructing an equivalent circuit is described.

[0091] Among them, sample slurry is involved. Sample slurry is a slurry with a specific formula used for the preparation of battery electrodes. Its composition and proportion reflect the preliminary or optimized selection of electrode materials in battery design.

[0092] Among them, sample batteries are involved. The sample batteries are cells prepared from sample slurries according to the battery structure and process requirements of the target type, and are used to evaluate the performance of specific slurry formulations in actual batteries.

[0093] Among them, sample performance parameters are involved. Sample performance parameters are performance indicators shown by sample batteries under various test conditions (such as charge and discharge cycles, temperature, current, etc.), including energy density, power density, cycle life, impedance characteristics, etc.

[0094] Among them, a control relationship is involved, which is the relationship between the composition of the sample slurry obtained through experiments and the performance parameters of the sample battery. This relationship can be used to guide the construction of equivalent circuit models and parameter fitting.

[0095] In the process of battery research and development, it is first necessary to prepare sample slurry and prepare sample batteries according to the type and requirements of the target battery. Next, a series of performance tests are performed to determine the performance parameters of the sample battery, such as energy density and charge and discharge efficiency. Then, based on the comparative relationship between the components of the slurry (such as the type and proportion of active materials, conductive agents, binders, and solvents) and the measured performance parameters, the influence of each component on battery performance can be deeply understood. Finally, based on these comparative relationships, an equivalent circuit model of the electrochemical impedance spectroscopy is constructed or optimized to more accurately simulate the electrochemical processes inside the battery and the electrochemical properties of the slurry.

[0096] In this way, through the analysis of the control relationship, it can be determined which slurry components have a significant impact on battery performance, so as to adjust the slurry formula in a targeted manner and optimize battery performance. The construction and fitting of the equivalent circuit model enables researchers to have an in-depth understanding of the electrochemical processes inside the battery, including ion migration, charge transfer, diffusion, etc., providing a theoretical basis for battery design. Based on the feedback of sample performance parameters, unnecessary slurry component use or process testing can be reduced, reducing R&D costs and time consumption.

[0097] Based on the above embodiments and optional embodiments, an optional implementation is provided, which is described in detail below.

[0098] In an optional embodiment of the present invention, a test and analysis method for the impedance of lithium-ion battery electrode slurry and its application, as well as an internal conductive network analysis system for lithium-ion positive electrode slurry are provided, including a test and analysis method for the impedance of lithium-ion battery electrode slurry and a test tool.

[0099] (I) Test method for impedance of lithium-ion battery electrode slurry:

[0100] S1: The main material, binder, conductive agent, dispersant, and functional additive are mixed with a solvent in a ratio of 50-100%, 0-20%, 0-20%, 0-10%, and 0-10% respectively, but not limited to this ratio range, to form a mixed slurry, and the total ratio is 100%.

[0101] Optionally, the main material, binder, conductive agent, dispersant, and functional additive may be mixed with a solvent in proportions of 50-100%, 0-20%, 0-20%, 0-10%, and 0-10%, respectively, but not limited to this ratio range, to form a mixed slurry, and the total ratio is 100%.

[0102] S2: Transfer the mixed slurry to the designed test fixture;

[0103] S3: The slurry impedance is then tested using an electrochemical impedance testing system.

[0104] Prepare lithium-ion positive electrode slurry samples with different proportions of conductive agent content, use a new test tool to test the conductivity of the slurry samples, analyze the conductivity performance of the slurry at different conductive agent contents, evaluate the structure and connection of the conductive network inside the slurry based on the corresponding equivalent circuit, and screen out the best positive electrode conductive agent material and the best conductive agent content based on the analysis results.

[0105] Specifically, the fitting method includes: conducting a power-on test on the conductive paste to obtain impedance test data of the conductive paste; using impedance analysis software to fit the initial value of component impedance in the electrochemical impedance test equivalent circuit based on the impedance test data; using impedance analysis software to fit the electrochemical impedance spectrum of the conductive paste based on the initial value of component impedance.

[0106] Optionally, in step S3, the electrochemical impedance testing system includes a first-order equivalent circuit, a second-order equivalent circuit and a third-order equivalent circuit connected in series in sequence, and the first-order equivalent circuit is connected in series with a charge transfer resistor; impedance analysis software: based on the impedance test data, the initial value of the element impedance in the electrochemical impedance test equivalent circuit is fitted to obtain the electrochemical impedance spectrum of the conductive slurry.

[0107] Optionally, the slurry preparation and impedance testing in steps S1, S2, and S3 may be performed at -20-100°C.

[0108] Optionally, in step S3, the frequency range of the impedance test is 0.01 Hz-8 MHz.

[0109] Optionally, in step S3, the disturbance voltage range of the impedance test is 10mV-1V.

[0110] Optionally, the solvent includes but is not limited to lithium battery solvents such as N-methylpyrrolidone, water, ethanol, and isopropanol.

[0111] Optionally, the solid content of the mixed slurry is 10%-100%, wherein the solid content refers to the content of solid matter.

[0112] Optionally, the conductive agent (conductive paste) includes any one of conductive carbon black, carbon nanotubes, carbon nanorods, carbon fibers or graphene, or a combination of at least two of them.

[0113] Optionally, the main material includes any one of lithium cobalt oxide, lithium manganese oxide, lithium nickel manganese cobalt oxide, lithium iron phosphate, lithium manganese iron phosphate, lithium nickel cobalt aluminum oxide, lithium titanate, graphite, and silicon, or a combination of at least two of them.

[0114] Optionally, the binder includes any one of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), carboxymethyl cellulose (CMC), styrene-butadiene rubber (SBR), polyacrylic acid (PAA), polyacrylonitrile (PAN), polyimide (PI), perfluorosulfonic acid ionomer (Nafion), natural extract binder, conductive binder, self-healing binder, and thermoplastic polymer, or a combination of at least two thereof.

[0115] Optionally, the dispersant includes an oily system dispersant and an aqueous system dispersant.

[0116] Optionally, other functional additives include wetting agents, thickeners, anti-cracking agents, etc. Among them, wetting agents are functional additives used to reduce the viscosity of the slurry and promote the slurry to form a stable suspension. Thickeners are functional additives used to increase the viscosity of the slurry and improve the stability of the slurry. Anti-cracking agents are functional additives used to prevent cracking during the slurry coating process.

[0117] (II) Test tooling:

[0118] Figure 2 is a schematic diagram of a test tool provided in an optional embodiment of the present invention, such as Figure 2 As shown, it includes electrodes on both sides and a content visualization test tube for conducting a conductivity test on a lithium-ion positive electrode slurry sample, including a test fixture with a specific structure and function, a test instrument, and a third-order equivalent circuit fitting method for an electrochemical impedance spectroscopy.

[0119] Optional, test kit including electrodes on both sides and cuvette for content visualization.

[0120] Optionally, the electrodes on both sides of the test fixture include at least one metal selected from the following: iron (Fe), copper (Cu), gold (Au), silver (Ag), aluminum (Al), cobalt (Co), chromium (Cr), manganese (Mn), molybdenum (Mo), titanium (Ti), zirconium (Zr), tin (Sn), vanadium (V), niobium (Nb), tantalum (Ta), hafnium (Hf) or a combination of these metals.

[0121] Optionally, the test tool content visualization test tube materials include but are not limited to polyvinyl chloride PVC, unplasticized polyvinyl chloride UPVC, polypropylene PP, polyethylene PE, polypropylene random copolymer PPR, cross-linked polyethylene PEX, glass, mica sheets, inorganic ceramic materials, etc.

[0122] (III) Third-order equivalent circuit of electrochemical impedance spectroscopy:

[0123] Figure 3 is a schematic diagram of a slurry internal impedance fitting circuit provided in an optional embodiment of the present invention, such as Figure 3As shown in FIG. 1 , the conductive paste equivalent circuit model is constructed based on the chemical composition analysis in the electrode paste. The third-order equivalent circuit includes a first-order equivalent circuit, a second-order equivalent circuit, and a third-order equivalent circuit connected in series in sequence. The first-order equivalent circuit is connected in series with the charge transfer resistor. The frequency band of the AC test current corresponding to the first-order equivalent circuit is greater than the frequency band of the AC test current corresponding to the second-order equivalent circuit, and the frequency band of the AC test current corresponding to the second-order equivalent circuit is greater than the frequency band of the AC test current corresponding to the third-order equivalent circuit.

[0124] Among them, Rso represents the solution resistance, Rp represents the transmission path resistance, Rdl represents the double layer resistance between the conductive agent and the main material, CPE (not involved in the figure, used to introduce CPES) is a component used to fit the non-ideal capacitance behavior in the impedance spectrum. It can describe the phase change characteristics of the dielectric material at different frequencies. This is because the capacitance of the real material usually does not show the 90-degree phase of the ideal capacitance at all frequencies. CPEs is used to describe the constant phase element of the interface between the binder and the solvent. It describes the capacitance behavior at the contact interface between the solution and the solute, which helps to understand the interaction and dispersion state between the two. CPEp usually represents the constant phase element of the interface between the binder and the main material (such as the active material of the lithium-ion battery), reflecting the surface electrochemical properties of the active material and the formation of the double layer. CPEdl represents the constant phase element of the interface between the conductive agent and the main material. It describes the capacitance behavior at the contact interface between the conductive agent and the active material, which helps to understand the interaction and dispersion state between the two. Cdl usually refers to the "double layer capacitance" (Double Layer Capacitance), which is an important parameter in the electrochemical system. In electrochemical impedance spectroscopy (EIS) analysis, Cdl is a measure of the capacitive properties of the double layer structure formed at the electrochemical interface (usually the electrode / electrolyte interface). When the ions in the electrolyte contact the charged electrode surface, a double layer consisting of the electrode surface charge and the electrolyte ions that counteract it is formed. The formation and change of this double layer has an important influence on the rate and efficiency of the electrochemical reaction.

[0125] As an optional implementation, the test tool content visualization test tube materials include but are not limited to PVC, UPVC, PP, PE, PPR, PEX, glass, mica sheets, inorganic ceramic materials, etc. In the following examples, lithium manganese iron phosphate is used as the main material, conductive carbon black SP is used as the conductive agent, copper wire is used as the tooling electrode, and PVC is used as the test tube material. The designed electrochemical impedance spectroscopy third-order equivalent circuit is adopted, 10mV is used as the disturbance voltage, and the measurement frequency range is 0.01Hz-1MHz, and the application of the test and analysis method of the impedance of the lithium-ion battery electrode slurry is described in more detail.

[0126] Figure 4is a comparison chart of slurry impedance data with different conductive agent contents provided in an optional embodiment of the present invention. The test results are as follows Figure 4 As shown. 095-2 represents method 1, 250-2 represents method 2, and 450-2 represents method 3. The "fit" represents the curve fitted by the Zview software combined with the third-order equivalent circuit. The fit curve is very close to the original actual curve, which is used to illustrate the accuracy of the third-order equivalent circuit. The difference between the three methods is that the content of the conductive agent is changed, and the other formulas are unchanged. 095 represents 0.95% conductive agent.

[0127] 1) Method 1:

[0128] Add appropriate amount of PVDF and N-methylpyrrolidone (NMP) to a vacuum mixer and stir into a glue solution for use. Add 0.95% conductive slurry (calculated according to the conductive agent SP content) to the homogenizer, then add a glue solution containing 1.5% PVDF, stir with a homogenizer at 850rpm for 10min, slowly add 97.55% lithium manganese iron phosphate, stir with a homogenizer at 850rpm for 10min, and prepare a mixture with a total weight of 80g and a total solid content of about 50%. After stirring, transfer the mixed slurry to the test fixture and test it with an impedance tester. The test results are as follows: Figure 4 shown.

[0129] 2) Method 2:

[0130] Add appropriate amount of PVDF and NMP to the vacuum mixer and stir into glue for use. Add 2.5% conductive slurry (calculated according to the conductive agent SP content) to the homogenizer, then add glue containing 1.5% PVDF, stir with a homogenizer at 850rpm for 10min, slowly add 96% lithium manganese iron phosphate, stir with a homogenizer at 850rpm for 10min, and prepare a mixture with a total weight of 80g and a total solid content of about 50%. After stirring, transfer the mixed slurry to the test fixture and test it with an impedance tester. The test results are as follows: Figure 4 shown.

[0131] 3) Method 3:

[0132] Add appropriate amount of PVDF and NMP to the vacuum mixer and stir into glue for use. Add 4.5% conductive slurry (calculated according to the conductive agent SP content) to the homogenizer, then add glue containing 1.5% PVDF, stir with a homogenizer at 850rpm for 10min, slowly add 94% lithium manganese iron phosphate, stir with a homogenizer at 850rpm for 10min, and prepare a mixture with a total weight of 80g and a total solid content of about 50%. After stirring, transfer the mixed slurry to the test fixture and test it with an impedance tester. The test results are as follows: Figure 4 shown.

[0133] The results of methods 1 to 3 were imported into the impedance analysis software, and the third-order equivalent circuit of electrochemical impedance spectroscopy was used for fitting, and the following conclusions were obtained.

[0134] in conclusion: Figure 5 is the slurry internal impedance fitting data provided by the optional embodiment of the present invention, such as Figure 4 , Figure 5 As shown, the curves 095-2-fit, 250-2-fit, and 450-2-fit fitted by the designed fitting circuit are very close to the actual curves, indicating that the equivalent circuit accurately presents the state of the conductive network inside the slurry. Furthermore, with the increase of the SP content of the conductive slurry, the Rso solution resistance and the Rp transmission path resistance decrease significantly, that is, the increase of the conductive agent improves the conductivity of the electrode slurry and reduces the resistance. The Rdl double-layer resistance between the conductive agent and the main material first decreases and then increases, which illustrates the dispersion condition between the conductive agent and the main material. The CPEp and CPEdl data further illustrate the dispersion condition between the conductive agent, the main material, and the PVDF binder.

[0135] Through the above optional implementation, at least the following beneficial effects can be achieved:

[0136] (1) An optional embodiment of the present invention provides a tool that can be directly used to test the slurry impedance. Content visualization can be used to control the slurry content. Fixed tooling and unified variables make data results more accurate and reduce random errors. The test electrodes on both sides facilitate the mixing and transfer of the slurry.

[0137] (2) An optional embodiment of the present invention provides an electrochemical impedance testing system and analysis method based on the analysis of the chemical composition in the electrode slurry, which can accurately and quickly obtain the composition of the internal slurry conductive network, can quickly and accurately reveal the situation of the internal conductive network of the slurry, and can be used to screen positive electrode conductive agent materials.

[0138] (3) An optional embodiment of the present invention provides a method for quickly screening the types and contents of conductive agents and the types and contents of main materials, and a method for evaluating and screening slurries with different contents of conductive agents using the above-mentioned analysis system. This solves the problem that the screening of electrode slurry formulas is cumbersome and inefficient, and achieves the purpose of quickly and accurately evaluating the conductive network inside the slurry under different formulas. It can provide a more comprehensive understanding of the conductive network structure inside the electrode slurry, providing an important reference for the design and optimization of lithium-ion electrode materials, thereby optimizing battery performance.

[0139] It should be noted that, for the above-mentioned method embodiments, for the sake of simplicity, they are all described as a series of action combinations, but those skilled in the art should know that the present invention is not limited by the described action sequence, because according to the present invention, certain steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present invention.

[0140] Through the description of the above implementation methods, those skilled in the art can clearly understand that the method according to the above embodiment can be implemented by means of software plus a necessary general hardware platform, and of course can also be implemented by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, a magnetic disk, or an optical disk), and includes a number of instructions for a terminal device (which can be a mobile phone, a computer, a server, or a network device, etc.) to execute the methods of various embodiments of the present invention.

[0141] Example 2

[0142] According to an embodiment of the present invention, a device for implementing the above-mentioned method for predicting performance parameters of a battery cell is also provided. Figure 6 is a structural block diagram of a device for predicting performance parameters of a battery cell according to an embodiment of the present invention. Figure 6 As shown, the device includes: an acquisition module 602, a determination module 604, a fitting module 606 and a prediction module 608. The device is described in detail below.

[0143] An acquisition module 602 is used to acquire a target slurry, wherein the target slurry is used to construct a target type of battery cell; a determination module 604 is connected to the acquisition module 602, and is used to determine the test data corresponding to the target slurry under the test parameters, wherein the test data includes impedance test data; a fitting module 606 is connected to the determination module 604, and is used to input the impedance test data into an equivalent circuit model for fitting to obtain a plurality of circuit parameter values, wherein the equivalent circuit model is constructed according to the target type of battery cell, and the equivalent circuit model includes four sub-circuits, the first sub-circuit includes a charge transfer resistor, the second sub-circuit is a solution resistor connected in parallel with a first constant phase element, and the third sub-circuit is a circuit diagram of ... The fourth sub-circuit is a parallel connection between an active material resistor and a second constant phase element, the fourth sub-circuit is a parallel connection between a double-layer resistor and a capacitor and a third constant phase element, the first constant phase element is a constant phase element representing the interface characteristics between a binder and a solvent, the second constant phase element is a constant phase element representing the interface characteristics between a binder and an active material, the third constant phase element is a constant phase element representing the interface characteristics between a conductive agent and an active material, the double-layer resistor and the capacitor are obtained by connecting the double-layer resistor and the double-layer capacitor in series, and the four sub-circuits are connected in series in sequence; a prediction module 608 is connected to the above-mentioned fitting module 606, and is used to predict the performance parameters of a battery cell made using a target slurry under test parameters based on multiple circuit parameter values.

[0144] It should be noted here that the above-mentioned acquisition module 602, determination module 604, fitting module 606 and prediction module 608 correspond to steps S102 to S108 in implementing the battery cell performance parameter prediction method, and the instances and application scenarios implemented by the multiple modules are the same as the corresponding steps, but are not limited to the contents disclosed in the above-mentioned embodiment 1.

[0145] Example 3

[0146] According to another aspect of an embodiment of the present invention, there is also provided an electronic device, comprising: a processor; and a memory for storing instructions executable by the processor, wherein the processor is configured to execute instructions to implement any of the above-mentioned methods for predicting battery cell performance parameters.

[0147] Example 4

[0148] According to another aspect of an embodiment of the present invention, a computer-readable storage medium is provided. When instructions in the computer-readable storage medium are executed by a processor of an electronic device, the electronic device can execute any of the above-mentioned methods for predicting battery cell performance parameters.

[0149] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0150] In the above embodiments of the present invention, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0151] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of the units can be a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0152] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0153] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0154] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, RandomAccess Memory), mobile hard disk, magnetic disk or optical disk and other media that can store program codes.

[0155] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for predicting battery cell performance parameters, characterized in that: include: Obtaining a target slurry, wherein the target slurry is used to construct a target type of battery cell; Determining test data corresponding to the target slurry under test parameters, wherein the test data includes impedance test data; The impedance test data is input into an equivalent circuit model for fitting to obtain multiple circuit parameter values, wherein the equivalent circuit model is constructed according to the target type of battery cell, and the equivalent circuit model includes four subcircuits, the first subcircuit includes a charge transfer resistance, the second subcircuit is a solution resistance connected in parallel with a first constant phase element, the third subcircuit is an active material resistance connected in parallel with a second constant phase element, and the fourth subcircuit is a double-layer resistance and capacitance connected in parallel with a third constant phase element, the first constant phase element is a constant phase element representing the interface characteristics between a binder and a solvent, the second constant phase element is a constant phase element representing the interface characteristics between a binder and an active material, the third constant phase element is a constant phase element representing the interface characteristics between a conductive agent and an active material, the double-layer resistance and capacitance are obtained by connecting a double-layer resistance and a double-layer capacitance in series, and the four subcircuits are connected in series in sequence; According to the multiple circuit parameter values, performance parameters of a battery cell made using the target slurry under the test parameters are predicted.

2. The method according to claim 1, characterized in that The method of predicting the performance parameters of the battery cell made of the target slurry under the test parameters based on the multiple circuit parameter values ​​includes: In the case where the target slurry includes an electrode material, a conductive agent, and a solvent, the electrode material includes an active substance, and the multiple circuit parameter values ​​include a fitted charge transfer resistance value, a fitted solution resistance value, a fitted active substance resistance value, a fitted double layer resistance value, and a fitted constant phase element value, determining the charge transfer efficiency performance of the solvent and the electrode material according to the fitted charge transfer resistance value; Determining the impedance of the conductive path formed by the binder and the conductive material according to the resistance value of the fitting solution; Determining the active material impedance of the active material inside the electrode material according to the fitted active material resistance value; Determining the charge transfer performance between the conductive agent and the active material according to the fitted double-layer resistance value; Determining the dispersion performance of each component in the target slurry according to the fitted constant phase element value; The performance parameters of the battery cell made using the target slurry under the test parameters are predicted based on the charge transfer efficiency performance, the conductive path impedance, the active material impedance, the charge transport performance and the dispersion performance.

3. The method according to claim 2, characterized in that The method of predicting the performance parameters of the battery cell made of the target slurry under the test parameters based on the charge transfer efficiency performance, the conductive path impedance, the active material impedance, the charge transport performance and the dispersion performance includes: In the case where the electrode material further includes a binder, and the fitted constant phase element value includes a first constant phase element value, a second constant phase element value, and a third constant phase element value, determining a first sub-contact property between the binder and the solvent according to the first constant phase element value; determining a second sub-contact property between the binder and the active material according to the second constant phase element value; Determining a third sub-contact property between the conductive agent and the active material according to the third constant phase element value; Determining a contact performance corresponding to the electrode material according to the first sub-contact performance, the second sub-contact performance, and the third sub-contact performance; The performance parameters of the battery cell made using the target slurry under the test parameters are predicted based on the charge transfer efficiency performance, the conductive path impedance, the active material impedance, the charge transport performance, the dispersion performance and the contact performance.

4. The method according to claim 1, characterized in that: The determining of the test data corresponding to the target slurry under the test parameters includes: Transferring the target slurry to a predetermined test fixture, wherein the predetermined test fixture comprises a target test tube, a first conductive electrode, and a second conductive electrode, wherein the first conductive electrode is located on a first side of the target test tube, and the second conductive electrode is located on a second side of the target test tube; The predetermined test tool is started under the test parameters to obtain the test data.

5. The method according to claim 1, characterized in that: The frequency band of the AC test current corresponding to the second subcircuit is greater than the frequency band of the AC test current corresponding to the third subcircuit, and the frequency band of the AC test current corresponding to the third subcircuit is greater than the frequency band of the AC test current corresponding to the fourth subcircuit.

6. The method according to claim 1, characterized in that After predicting the performance parameters of the battery cell made of the target slurry under the test parameters according to the multiple circuit parameter values, the method further includes: When the performance parameter is less than a predetermined threshold, determining the composition parameter of the target slurry; The composition parameters are adjusted to obtain a renewal slurry to determine the performance parameters corresponding to the renewal slurry.

7. The method according to any one of claims 1 to 6, characterized in that: Before inputting the impedance test data into an equivalent circuit model for fitting to obtain a plurality of circuit parameter values, the method further includes: Obtaining a sample slurry and a sample battery constructed from the sample slurry, wherein the sample battery is a battery of the target type; determining sample performance parameters of the sample battery; Determining the relationship between the composition of the sample slurry and the sample performance parameters; The equivalent circuit model is constructed according to the control relationship.

8. A battery cell performance parameter prediction device, characterized in that: include: An acquisition module, used for acquiring a target slurry, wherein the target slurry is used for constructing a target type of battery cell; A determination module, used to determine the test data corresponding to the target slurry under the test parameters, wherein the test data includes impedance test data; A fitting module, for inputting the impedance test data into an equivalent circuit model for fitting to obtain a plurality of circuit parameter values, wherein the equivalent circuit model is constructed according to the target type of battery cell, and the equivalent circuit model includes four subcircuits, the first subcircuit includes a charge transfer resistor, the second subcircuit is a solution resistor connected in parallel with a first constant phase element, the third subcircuit is an active material resistor connected in parallel with a second constant phase element, and the fourth subcircuit is a double-layer resistor and capacitor connected in parallel with a third constant phase element, the first constant phase element is a constant phase element representing the interface characteristics between a binder and a solvent, the second constant phase element is a constant phase element representing the interface characteristics between a binder and an active material, the third constant phase element is a constant phase element representing the interface characteristics between a conductive agent and an active material, the double-layer resistor and capacitor are obtained by connecting a double-layer resistor and a double-layer capacitor in series, and the four subcircuits are connected in series in sequence; The prediction module is used to predict the performance parameters of the battery cell made by using the target slurry under the test parameters according to the multiple circuit parameter values.

9. An electronic device, characterized in that: include: processor; a memory for storing instructions executable by the processor; Wherein, the processor is configured to execute the instructions to implement the battery cell performance parameter prediction method as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: When the instructions in the computer-readable storage medium are executed by a processor of an electronic device, the electronic device is enabled to execute the method for predicting battery cell performance parameters as described in any one of claims 1 to 7.

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