Method and device for calculating electrochemical impedance of battery

Abstract

The invention discloses an electrochemical impedance calculation method and device of a battery, and relates to the field of batteries, and the method comprises the steps: constructing a P2D model corresponding to the battery; acquiring electric potentials corresponding to different positions in the battery by the P2D model; acquiring polarization values corresponding to different positions in the battery according to the potentials corresponding to different positions in the battery; acquiring impedance values corresponding to different positions in the battery according to the polarization values corresponding to different positions in the battery; and finally outputting impedance values corresponding to different positions in the battery. According to the invention, the battery performance can be better evaluated.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a method and device for calculating electrochemical impedance of a battery. Background Art

[0002] In the field of lithium-ion battery technology, electrochemical impedance spectroscopy (EIS) is a key analytical method used to evaluate the internal resistance of batteries and the performance of electrode materials. EIS can provide information about charge transfer, ion migration, and electrode / electrolyte interface dynamics, which is essential for understanding and improving battery performance.

[0003] However, traditional EIS measurements obtain impedance values ​​in the frequency domain and cannot better evaluate battery performance. Summary of the invention

[0004] The purpose of this application is to provide a method and device for calculating the electrochemical impedance of a battery, which can better evaluate the battery performance.

[0005] To achieve the above objectives, this application provides the following solutions:

[0006] In a first aspect, the present application provides a method for calculating the electrochemical impedance of a battery, the method comprising:

[0007] Construct the P2D model corresponding to the battery;

[0008] Acquire the electric potential corresponding to different positions inside the battery according to the P2D model;

[0009] Obtaining polarization values ​​corresponding to different positions inside the battery according to the electric potentials corresponding to different positions inside the battery;

[0010] Obtaining impedance values ​​corresponding to different positions inside the battery according to polarization values ​​corresponding to different positions inside the battery;

[0011] The impedance values ​​corresponding to different positions inside the battery are output.

[0012] In a second aspect, the present application provides a battery electrochemical impedance calculation device, the battery electrochemical impedance calculation device comprising:

[0013] A construction module is used to construct a P2D model corresponding to the battery;

[0014] A first acquisition module, used for acquiring the electric potential corresponding to different positions inside the battery according to the P2D model;

[0015] A second acquisition module, used to acquire polarization values ​​corresponding to different positions inside the battery according to the electric potentials corresponding to different positions inside the battery;

[0016] A third acquisition module, used to acquire impedance values ​​corresponding to different positions inside the battery according to polarization values ​​corresponding to different positions inside the battery;

[0017] The output module is used to output the impedance values ​​corresponding to different positions inside the battery.

[0018] In a third aspect, the present application provides a computer device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the electrochemical impedance calculation method for a battery described in any one of the above.

[0019] In a fourth aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method for calculating the electrochemical impedance of a battery as described in any one of the above.

[0020] In a fifth aspect, the present application provides a computer program product, including a computer program, which, when executed by a processor, implements the steps of the electrochemical impedance calculation method of a battery as described in any one of the above.

[0021] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0022] The present application provides a method and device for calculating the electrochemical impedance of a battery, by constructing a P2D model corresponding to the battery; obtaining the electric potential corresponding to different positions inside the battery through the P2D model; obtaining the polarization value corresponding to different positions inside the battery according to the electric potential corresponding to different positions inside the battery; obtaining the impedance value corresponding to different positions inside the battery according to the polarization value corresponding to different positions inside the battery; and finally outputting the impedance value corresponding to different positions inside the battery. The present disclosure is based on the P2D model for impedance decomposition calculation. Since the P2D model is a high-precision electrochemical model, a more accurate decomposition result can be obtained after the impedance is decomposed, and since the P2D model is based on the impedance value obtained by time domain testing, the sum of the impedances of each part after decomposition is also equal to the overall impedance, which is in line with physical reality. Compared with the EIS technology based on frequency domain impedance decomposition, the obtained impedance has a stronger reference, and the battery performance can be better evaluated. In addition, the present disclosure is a non-destructive testing technology, which does not require destructive modification of the battery, reducing the cost of impedance testing. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 is a flow chart of a method for calculating electrochemical impedance of a battery according to an exemplary embodiment;

[0025] Figure 2 is a schematic diagram of battery pole piece thickness according to an exemplary embodiment;

[0026] Figure 3 A schematic diagram of functional modules of a battery electrochemical impedance calculation device provided in one embodiment of the present application;

[0027] Figure 4 A schematic diagram of the structure of a computer device provided in one embodiment of the present application. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0029] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0030] The electrochemical impedance spectroscopy of batteries is an important tool for studying battery performance and internal reaction mechanisms.

[0031] The electrochemical impedance of a battery refers to the resistance to current flow that the battery exhibits when a current signal is applied to the battery. It can be expressed in complex form, consisting of a real part (resistance) and an imaginary part (reactance).

[0032] By measuring the electrochemical impedance of a battery, battery evaluation, battery R&D, and battery fault detection can be performed.

[0033] In terms of battery evaluation, by measuring the electrochemical impedance at different frequencies, the battery performance, such as internal resistance, capacity, rate performance, etc., can be evaluated. For example, an increase in internal resistance may mean a decrease in battery performance. And because the electrochemical impedance of the battery changes as it is used and aged, by regularly measuring the impedance, the degree of battery aging can be understood and the battery life can be predicted.

[0034] In terms of battery research and development, different electrode materials have different electrochemical impedance characteristics. By measuring and analyzing the impedance of electrode materials, their electrochemical performance can be evaluated and the design and preparation methods of electrode materials can be optimized. Due to the structural design of the battery, such as the thickness and porosity of the electrode, the transmission of ions and electrons will be affected, which in turn affects the impedance of the battery. Adjusting the battery structure through electrochemical impedance can reduce impedance and improve battery performance. The properties of the electrolyte also have a great influence on the impedance of the battery. Measuring the battery impedance under different electrolyte compositions can optimize the electrolyte formulation and improve the performance and stability of the battery.

[0035] In terms of battery fault detection, when a battery fails, such as internal short circuit, electrode corrosion, etc., its electrochemical impedance will change significantly. By measuring the impedance, the type and location of the battery fault can be quickly diagnosed, providing a basis for maintenance and improvement.

[0036] The traditional EIS measurement steps are:

[0037] Prepare the battery: Make sure the battery is stable and can be measured. If it is a new battery, it may need some activation treatment.

[0038] Connect electrodes: Connect the positive and negative electrodes of the battery to the working electrode and the counter electrode respectively, and the reference electrode is also connected to the electrochemical workstation.

[0039] Set parameters: Set the frequency range, amplitude and other parameters of the AC signal on the electrochemical workstation. Generally speaking, the frequency range is from a few millihertz to several hundred kilohertz.

[0040] Take a measurement: Start the measurement program, and the electrochemical workstation will automatically apply an AC signal within the set frequency range and measure the impedance response of the battery. The measurement process usually takes a certain amount of time to ensure the accuracy of the data.

[0041] Data analysis: After the measurement is completed, the impedance data obtained can be analyzed using various software. Common analysis methods include drawing Nyquist diagrams (the relationship between the imaginary and real parts of impedance) and Bode diagrams (the change of impedance amplitude and phase angle with frequency).

[0042] Since EIS measurements obtain impedance values ​​in the frequency domain, the impedance values ​​in the time domain are often used more often in actual production. However, the result obtained by adding up the impedance values ​​of each part obtained by EIS is not equal to the impedance value in the time domain, so the reference value is weak. In addition, traditional EIS measurements usually require the use of special experimental equipment under laboratory conditions, which is not only time-consuming and labor-intensive, but also difficult to monitor the battery status online in real time.

[0043] In order to solve the above technical problems, the present disclosure proposes a battery impedance prediction method.

[0044] Figure 1 is a flow chart of a method for calculating electrochemical impedance of a battery according to an exemplary embodiment. Figure 1 As shown, the process includes the following steps S101-S105:

[0045] In step S101, a P2D model corresponding to the battery is constructed.

[0046] The P2D model, or Pseudo-Two-Dimensional model, is a mathematical model that simulates the thermal, electrical, and chemical processes of lithium-ion battery cells during the cycle. The model divides the battery cells into different control volumes and takes into account multiple factors such as the potential distribution, current distribution, concentration distribution, and electrochemical reaction kinetics within the electrode. Therefore, it can more accurately predict key performance indicators such as the battery's charge and discharge behavior and cycle life.

[0047] When constructing the P2D model corresponding to the battery, the following sub-steps A1-A2 may be included:

[0048] A1. Receive battery design information and battery material information;

[0049] A2. Build a P2D model based on design information and material information.

[0050] Among them, the design information includes at least the following information: the total thickness of the battery pole piece, the thickness of the negative pole piece, the total mass of the positive electrode, the total mass of the negative electrode and the thickness of the diaphragm; the material information includes at least the following information: the material radius, and the material lithium concentration-equilibrium voltage interpolation table. By inputting the above battery design information and battery material information into the original P2D model, a P2D model based on porous electrode theory can be constructed.

[0051] In step S102, the electric potentials corresponding to different positions inside the battery are obtained according to the P2D model.

[0052] In one embodiment, step S102 includes the following sub-steps B1-B2:

[0053] B1. Load current value into the P2D model.

[0054] B2. After loading the current value, the potential corresponding to different positions inside the battery is obtained by solving the liquid phase potential equation, solid phase potential equation and lithium ion diffusion equation in the electrode particles in the P2D model.

[0055] like Figure 2 As shown, in the P2D model, the total thickness of the battery electrode is L, the thickness of the negative electrode is Ln, the thickness of the diaphragm is Ls, and the thickness of the positive electrode is L-(Ln-Ls).

[0056] The liquid phase potential equation in the P2D model can be expressed as:

[0057] negative electrode:

[0058] Diaphragm:

[0059] positive electrode:

[0060] Boundary conditions: Negative electrode:

[0061] positive electrode:

[0062] Where x represents the coordinate in the thickness direction of the electrode sheet. When x is 0 to Ln, it represents the negative electrode sheet. When x is Ln to Ln+Ls, it represents the diaphragm. When x is Ln+Ls to L, it represents the positive electrode sheet. φe represents the electrolyte potential. j Li represents the electrochemical reaction current density, ce,n represents the lithium ion concentration of the negative electrode of the electrolyte, c e,se represents the lithium ion concentration of the electrolyte diaphragm, ce,p represents the lithium ion concentration of the electrolyte positive electrode, Represents the effective conductivity of lithium ions in the electrolyte of the negative electrode area, Represents the effective conductivity of lithium ions in the electrolyte in the diaphragm area, It represents the effective conductivity of lithium ions in the electrolyte of the positive electrode area. Represents the effective diffusion conductivity of lithium ions in the electrolyte of the negative electrode area, It represents the effective diffusion conductivity of lithium ions in the electrolyte of the diaphragm area. It represents the effective diffusion conductivity of lithium ions in the electrolyte in the positive electrode area.

[0063] The average value of the electrolyte potential in the negative electrode region is expressed as The electrolyte potential when x = 0 is the electrolyte potential on the negative electrode current collector side, expressed as When x = Ln, the electrolyte potential is the electrolyte potential on the negative electrode diaphragm side, expressed as

[0064] The average value of the electrolyte potential in the positive electrode region is expressed as When x = L, the electrolyte potential is the electrolyte potential on the positive electrode collector side, expressed as When x = Ln + Ls, the electrolyte potential is the electrolyte potential on the positive electrode diaphragm side, expressed as

[0065] The solid phase potential equation in the P2D model can be expressed as:

[0066] negative electrode:

[0067] positive electrode:

[0068] Boundary conditions: Negative electrode:

[0069] positive electrode:

[0070] Where I represents the charge and discharge current, A represents the effective area of ​​the electrode, φs represents the solid phase potential, represents the effective conductivity of the negative electrode particles, Represents the effective conductivity of the positive electrode particles;

[0071] The average value of φe-φs in the negative electrode region is η neg ; The average value of φe-φs in the positive electrode area is ηpo s ;

[0072] The diffusion equation of lithium ions in electrode particles is:

[0073]

[0074] Among them, c s is the lithium ion concentration of the electrode particles, r is the radius of the electrode particles, D s is the diffusion coefficient of lithium ions in the electrode particles.

[0075] Specifically, in the present disclosure, voltage probes are placed at different positions of the P2D model, and then current values ​​are loaded into the P2D model, so that the potentials corresponding to different positions inside the battery can be obtained through the probes.

[0076] For example, different positions of the P2D model may include: positive electrode current collector side, positive electrode separator side, negative electrode current collector side and negative electrode separator side, and then a particle center probe, a particle surface probe and a liquid phase probe are placed at each position to characterize the potential at different positions of the battery.

[0077] In the present disclosure, the potentials corresponding to different positions inside the battery obtained according to the P2D model include: the potentials corresponding to different positions of the positive electrode sheet and the potentials corresponding to different positions of the negative electrode sheet; the potentials corresponding to different positions of the positive electrode sheet include at least at least one of the following potentials: the potential average value of the electrolyte potential in the positive electrode region, the electrolyte potential on the positive electrode collector side, the electrolyte potential on the positive electrode diaphragm side, the average open circuit voltage on the surface of the positive electrode particles, the solid phase potential in the positive electrode region and the average open circuit voltage of the positive electrode particles; the potentials corresponding to different positions of the negative electrode sheet include at least at least one of the following potentials: the average value of the electrolyte potential in the negative electrode region, the electrolyte potential on the negative electrode collector side, the electrolyte potential on the negative electrode diaphragm side, the average open circuit voltage on the surface of the negative electrode particles, the solid phase potential in the negative electrode region and the average open circuit voltage of the negative electrode particles.

[0078] In step S103, polarization values ​​corresponding to different positions inside the battery are obtained according to the electric potentials corresponding to different positions inside the battery.

[0079] In the present disclosure, the polarization values ​​corresponding to different positions inside the battery include at least one of the following polarization values: the polarization value of the negative electrode liquid phase, the negative electrode electrochemical polarization value, the negative electrode diffusion polarization value, the polarization value of the diaphragm liquid phase, the polarization value of the positive electrode liquid phase, the positive electrode electrochemical polarization value and the positive electrode diffusion polarization value.

[0080] Specifically, the polarization value of the negative electrode liquid phase can be obtained according to the average value of the electrolyte potential in the negative electrode region and the electrolyte potential on the negative electrode current collector side. Specifically, the polarization value of the negative electrode liquid phase can be obtained by the following formula:

[0081]

[0082] Among them, L neg represents the polarization value of the negative electrode liquid phase, represents the average value of the electrolyte potential in the negative electrode region, represents the electrolyte potential on the negative electrode current collector side.

[0083] The polarization value of the positive electrode liquid phase can be obtained according to the average value of the electrolyte potential in the positive electrode region and the electrolyte potential on the positive electrode current collector side. Specifically, the polarization value of the positive electrode liquid phase can be obtained by the following formula:

[0084]

[0085] Among them, L pos represents the polarization value of the positive electrode liquid phase, represents the average electrolyte potential in the positive electrode region, represents the electrolyte potential on the positive electrode current collector side.

[0086] The polarization value of the diaphragm liquid phase can be obtained according to the electrolyte potential on the negative electrode diaphragm side and the electrolyte potential on the positive electrode diaphragm side. Specifically, the polarization value of the diaphragm liquid phase can be obtained by the following formula:

[0087]

[0088] Among them, L pos represents the polarization value of the diaphragm liquid phase, represents the electrolyte potential on the negative electrode diaphragm side, Represents the electrolyte potential on the positive electrode separator side.

[0089] The positive electrode electrochemical polarization value can be obtained according to the average potential of the positive electrode region and the average open circuit voltage on the surface of the positive electrode particles; wherein the average potential of the positive electrode region is the average value of the difference between the electrolyte potential of the positive electrode region and the solid phase potential of the positive electrode region. Specifically, the positive electrode electrochemical polarization value can be obtained by the following formula:

[0090]

[0091] Among them, LCT pos Represents the electrochemical polarization value of the positive electrode, η pos Indicates the positive electrode area φ e -φ s The average value of Represents the average open circuit voltage on the surface of the positive electrode particles.

[0092] The negative electrode electrochemical polarization value can be obtained according to the average potential of the negative electrode region and the average open circuit voltage on the surface of the negative electrode particles; wherein the average potential of the negative electrode region is the average value of the difference between the electrolyte potential of the negative electrode region and the solid phase potential of the negative electrode region. Specifically, the negative electrode electrochemical polarization value can be obtained by the following formula:

[0093]

[0094] Among them, LCT neg Represents the electrochemical polarization value of the negative electrode, η neg φ represents the negative electrode region e -φ s The average value of Represents the average open circuit voltage on the surface of negative electrode particles.

[0095] The negative electrode diffusion polarization value can be obtained according to the electrolyte potential on the negative electrode current collector side, the average open circuit voltage on the surface of the negative electrode particles, the average value of the electrolyte potential in the negative electrode region and the average open circuit voltage of the negative electrode particles. Specifically, the negative electrode diffusion polarization value can be obtained by the following formula:

[0096]

[0097] Among them, ds neg represents the negative electrode diffusion polarization value, represents the electrolyte potential on the negative electrode current collector side, represents the average open circuit voltage on the surface of negative electrode particles, represents the average value of the electrolyte potential in the negative electrode region, Represents the average open circuit voltage of the negative electrode particles.

[0098] The polarization value of the positive electrode liquid phase can be obtained according to the electrolyte potential on the positive electrode current collector side, the average open circuit voltage on the surface of the positive electrode particles, the average value of the electrolyte potential in the positive electrode region, and the average open circuit voltage of the positive electrode particles. Specifically, the polarization value of the positive electrode liquid phase can be obtained by the following formula:

[0099]

[0100] Among them, ds pos represents the positive electrode diffusion polarization value, represents the electrolyte potential on the positive electrode current collector side, represents the average open circuit voltage on the surface of the positive electrode particles, represents the average electrolyte potential in the positive electrode region, Represents the average open circuit voltage of the positive electrode particles.

[0101] The above open circuit voltage can be obtained by looking up the lithium ion concentration of the electrode particles of the particles and the material lithium concentration-equilibrium voltage interpolation table.

[0102] In step S104, impedance values ​​corresponding to different positions inside the battery are obtained according to polarization values ​​corresponding to different positions inside the battery.

[0103] The impedance values ​​corresponding to different positions inside the battery can be obtained according to the polarization values ​​and current values ​​corresponding to different positions inside the battery. Specifically, the impedance values ​​corresponding to different positions inside the battery are obtained by the following formula:

[0104] R neg =L neg / I;

[0105] R pos =L pos / I;

[0106] R sep =L sep / I;

[0107] RCT pos =LCT pos / I;

[0108] RCT neg =LCT pos / I;

[0109] Rds neg =ds neg / I;

[0110] Rds pos =ds pos / I;

[0111] Among them, R neg , R pos , R sep , RCT pos , RCT neg 、Rds neg 、Rds pos They respectively represent the negative electrode liquid phase impedance value, the positive electrode liquid phase impedance value, the diaphragm liquid phase impedance value, the negative electrode electrochemical impedance value, the positive electrode electrochemical impedance value, the negative electrode solid phase impedance value and the positive electrode solid phase impedance value.

[0112] Some or all of the impedance values ​​may be obtained according to actual needs, and the present disclosure does not impose any limitation thereto, and the impedance values ​​may be adjusted according to actual application scenarios.

[0113] In step S105, the impedance values ​​corresponding to different positions inside the battery are output.

[0114] In the present disclosure, after obtaining the impedance values ​​corresponding to different positions inside the battery, the following sub-steps C1-C3 may also be included:

[0115] C1. Calculate the sum of the impedance values ​​corresponding to different positions inside the battery as the total impedance value.

[0116] C2. According to the ratio of the impedance values ​​corresponding to different positions inside the battery to the total impedance value, the proportion of the impedance values ​​corresponding to different positions inside the battery in the total impedance value is obtained.

[0117] C3. Output the proportion of impedance values ​​corresponding to different positions inside the battery in the total impedance value.

[0118] After obtaining the impedance values ​​corresponding to different positions inside the battery, they can be added together to obtain the total impedance value, and then the proportion of the impedance values ​​corresponding to different positions inside the battery in the total impedance value can be obtained.

[0119] For example:

[0120]

[0121] Among them, R neg％ Represents the proportion of the polarization value of the negative electrode liquid phase.

[0122] The traditional method of obtaining time domain impedance through three-electrode testing requires battery modification, which has a long modification cycle. It is also a destructive testing technology, and the accuracy of the final measured impedance value depends on the modification level, so the distribution range of the results obtained is relatively large.

[0123] Although the EIS impedance decomposition technology does not require battery modification, the EIS test obtains impedance values ​​in the frequency domain. However, in actual production, it is often more often used in the time domain, which is closer to constant current testing. The result of adding up the impedance of each part obtained by EIS is not equal to the impedance of the constant current test, so it is less useful as a reference.

[0124] In the present disclosure, a P2D model corresponding to a battery is constructed; the electric potential corresponding to different positions inside the battery is obtained according to the P2D model; the polarization value corresponding to different positions inside the battery is obtained according to the electric potential corresponding to different positions inside the battery; the impedance value corresponding to different positions inside the battery is obtained according to the polarization value corresponding to different positions inside the battery; and finally the impedance value corresponding to different positions inside the battery is output. The present disclosure is based on the P2D model for impedance decomposition calculation. Since the P2D model is a high-precision electrochemical model, a more accurate decomposition result can be obtained after the impedance is decomposed. Moreover, since the P2D model is based on the impedance value obtained by time domain testing, the sum of the impedances of each part after decomposition is also equal to the overall impedance, which is in line with physical reality. Compared with the EIS technology based on frequency domain impedance decomposition, the obtained impedance has a stronger reference, and the battery performance can be better evaluated. Moreover, the present disclosure is a non-destructive testing technology, which does not require destructive modification of the battery, and reduces the cost of impedance testing.

[0125] Furthermore, the method disclosed in the present invention directly extracts electrochemical impedance information from the P2D model by means of numerical simulation, without the need for experimental measurement, so that the state of the battery can be monitored in real time. Moreover, since the impedance results obtained are more accurate, the battery management strategy can be better optimized and the battery life can be extended.

[0126] In the present disclosure, since there is no need to disassemble the battery for analysis, it can be non-destructive. Since the results are obtained directly through time domain analysis, they are more accurate, so that the calculation method can be applied in real time in electric vehicle management systems or large energy storage systems. In addition, the calculation method can also help researchers to have a deeper understanding of the complex physical and chemical processes inside the battery, and provide a theoretical basis for battery design optimization.

[0127] Based on the same inventive concept, the present application also provides an electrochemical impedance calculation device for implementing the above-mentioned battery. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above-mentioned method, so the specific limitations in the embodiments of the electrochemical impedance calculation device for one or more batteries provided below can refer to the limitations of the electrochemical impedance calculation method for the battery above, and will not be repeated here.

[0128] In an exemplary embodiment, Figure 3 As shown, a battery electrochemical impedance calculation device is provided, comprising:

[0129] A construction module 11 is used to construct a P2D model corresponding to the battery;

[0130] A first acquisition module 12, used to acquire the electric potential corresponding to different positions inside the battery according to the P2D model;

[0131] A second acquisition module 13, used to acquire polarization values ​​corresponding to different positions inside the battery according to the electric potentials corresponding to different positions inside the battery;

[0132] A third acquisition module 14 is used to acquire impedance values ​​corresponding to different positions inside the battery according to polarization values ​​corresponding to different positions inside the battery;

[0133] The first output module 15 is used to output impedance values ​​corresponding to different positions inside the battery.

[0134] As an optional implementation manner, the first acquisition module 12 is specifically configured to:

[0135] Loading current value to the P2D model;

[0136] After the current value is loaded, the potentials corresponding to different positions inside the battery are obtained by solving the liquid phase potential equation, the solid phase potential equation and the diffusion equation of lithium ions in the electrode particles in the P2D model.

[0137] As an optional implementation manner, the third acquisition module 14 is specifically configured to:

[0138] The impedance values ​​corresponding to different positions inside the battery are obtained according to the polarization values ​​corresponding to different positions inside the battery and the current values.

[0139] As an optional embodiment, the electrochemical impedance calculation device of the battery further includes:

[0140] A calculation module, used to calculate the sum of impedance values ​​corresponding to different positions inside the battery as a total impedance value;

[0141] A fourth acquisition module, configured to acquire a proportion of the impedance values ​​corresponding to different positions inside the battery in the total impedance value according to a ratio of the impedance values ​​corresponding to different positions inside the battery to the total impedance value;

[0142] The second output module is used to output the proportion of the impedance values ​​corresponding to different positions inside the battery in the total impedance value.

[0143] As an optional implementation, the construction module 11 is specifically used for:

[0144] Receiving design information of the battery and material information of the battery;

[0145] The P2D model is constructed according to the design information and the material information.

[0146] As an optional embodiment, the potentials corresponding to different positions inside the battery include: the potentials corresponding to different positions of the positive electrode sheet and the potentials corresponding to different positions of the negative electrode sheet; the potentials corresponding to different positions of the positive electrode sheet include at least at least one of the following potentials: the potential average of the electrolyte potential in the positive electrode region, the electrolyte potential on the positive electrode collector side, the electrolyte potential on the positive electrode diaphragm side, the average open circuit voltage on the surface of the positive electrode particles, the solid phase potential in the positive electrode region and the average open circuit voltage of the positive electrode particles; the potentials corresponding to different positions of the negative electrode sheet include at least at least one of the following potentials: the average of the electrolyte potential in the negative electrode region, the electrolyte potential on the negative electrode collector side, the electrolyte potential on the negative electrode diaphragm side, the average open circuit voltage on the surface of the negative electrode particles, the solid phase potential in the negative electrode region and the average open circuit voltage of the negative electrode particles.

[0147] As an optional embodiment, the polarization values ​​corresponding to different positions inside the battery include at least one of the following polarization values: the polarization value of the negative electrode liquid phase, the negative electrode electrochemical polarization value, the negative electrode diffusion polarization value, the polarization value of the diaphragm liquid phase, the polarization value of the positive electrode liquid phase, the positive electrode electrochemical polarization value and the positive electrode diffusion polarization value.

[0148] As an optional implementation manner, the second acquisition module 13 is specifically configured to:

[0149] Obtaining a polarization value of the negative electrode liquid phase according to an average value of the electrolyte potential in the negative electrode region and the electrolyte potential on the negative electrode current collector side;

[0150] Obtaining the polarization value of the positive electrode liquid phase according to the average value of the electrolyte potential in the positive electrode region and the electrolyte potential on the positive electrode current collector side;

[0151] Obtaining a polarization value of the diaphragm liquid phase according to the electrolyte potential on the negative electrode diaphragm side and the electrolyte potential on the positive electrode diaphragm side;

[0152] The positive electrode electrochemical polarization value is obtained according to the average potential of the positive electrode region and the average open circuit voltage on the surface of the positive electrode particles; wherein the average potential of the positive electrode region is the average value of the difference between the electrolyte potential of the positive electrode region and the solid phase potential of the positive electrode region;

[0153] The negative electrode electrochemical polarization value is obtained according to the average potential of the negative electrode region and the average open circuit voltage on the surface of the negative electrode particles; wherein the average potential of the negative electrode region is the average value of the difference between the electrolyte potential of the negative electrode region and the solid phase potential of the negative electrode region;

[0154] Obtaining the negative electrode diffusion polarization value according to the electrolyte potential on the negative electrode current collector side, the average open circuit voltage on the surface of the negative electrode particles, the average value of the electrolyte potential in the negative electrode region, and the average open circuit voltage of the negative electrode particles;

[0155] Obtaining the polarization value of the positive electrode liquid phase according to the electrolyte potential on the positive electrode current collector side, the average open circuit voltage on the surface of the positive electrode particles, the average value of the electrolyte potential in the positive electrode region, and the average open circuit voltage of the positive electrode particles;

[0156] As an optional implementation,

[0157] The design information includes at least the following information: total thickness of battery pole pieces, thickness of negative pole pieces, total mass of positive electrode, total mass of negative electrode and thickness of separator;

[0158] The material information includes at least the following information: material radius, and a material lithium concentration-equilibrium voltage interpolation table.

[0159] In an exemplary embodiment, a computer device is provided. The computer device may be a server or a terminal. The internal structure diagram thereof may be as follows: Figure 4 As shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, referred to as I / O) and a communication interface. Among them, the processor, the memory and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store data required for the electrochemical impedance calculation of the battery. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, the electrochemical impedance calculation method of the battery is implemented.

[0160] Those skilled in the art will understand that Figure 4 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0161] In an exemplary embodiment, a computer device is further provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above-mentioned method embodiments when executing the computer program.

[0162] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program, and when the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0163] In an exemplary embodiment, a computer program product is provided, including a computer program, and when the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0164] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0165] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM may be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0166] The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. The non-relational database may include a distributed database based on blockchain, etc., but is not limited thereto. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but is not limited thereto.

[0167] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0168] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A method for calculating electrochemical impedance of a battery, characterized in that: The electrochemical impedance calculation method of the battery includes: Construct the P2D model corresponding to the battery; Acquire the electric potential corresponding to different positions inside the battery according to the P2D model; Obtaining polarization values ​​corresponding to different positions inside the battery according to the electric potentials corresponding to different positions inside the battery; Obtaining impedance values ​​corresponding to different positions inside the battery according to polarization values ​​corresponding to different positions inside the battery; The impedance values ​​corresponding to different positions inside the battery are output.

2. The method for calculating the electrochemical impedance of a battery according to claim 1, characterized in that: The obtaining the electric potentials corresponding to different positions inside the battery according to the P2D model includes: Loading current value to the P2D model; After the current value is loaded, the potentials corresponding to different positions inside the battery are obtained by solving the liquid phase potential equation, the solid phase potential equation and the diffusion equation of lithium ions in the electrode particles in the P2D model.

3. The method for calculating the electrochemical impedance of a battery according to claim 2, characterized in that: The obtaining the impedance values ​​corresponding to different positions inside the battery according to the polarization values ​​corresponding to different positions inside the battery includes: The impedance values ​​corresponding to different positions inside the battery are obtained according to the polarization values ​​corresponding to different positions inside the battery and the current values.

4. The method for calculating the electrochemical impedance of a battery according to claim 1, characterized in that: The electrochemical impedance calculation method of the battery also includes: Calculating the sum of the impedance values ​​corresponding to different positions inside the battery as the total impedance value; According to the ratio of the impedance values ​​corresponding to different positions inside the battery to the total impedance value, obtaining the proportion of the impedance values ​​corresponding to different positions inside the battery in the total impedance value; The proportion of the impedance values ​​corresponding to different positions inside the battery in the total impedance value is output.

5. The method for calculating the electrochemical impedance of a battery according to claim 1, characterized in that: The construction of the P2D model corresponding to the battery specifically includes: Receiving design information of the battery and material information of the battery; The P2D model is constructed according to the design information and the material information.

6. The method for calculating the electrochemical impedance of a battery according to any one of claims 1 to 5, characterized in that: The potentials corresponding to different positions inside the battery include: the potentials corresponding to different positions of the positive electrode sheet and the potentials corresponding to different positions of the negative electrode sheet; the potentials corresponding to different positions of the positive electrode sheet include at least one of the following potentials: the potential average value of the electrolyte potential in the positive electrode region, the electrolyte potential on the positive electrode collector side, the electrolyte potential on the positive electrode diaphragm side, the average open circuit voltage on the surface of the positive electrode particles, the solid phase potential in the positive electrode region and the average open circuit voltage of the positive electrode particles; the potentials corresponding to different positions of the negative electrode sheet include at least one of the following potentials: the average value of the electrolyte potential in the negative electrode region, the electrolyte potential on the negative electrode collector side, the electrolyte potential on the negative electrode diaphragm side, the average open circuit voltage on the surface of the negative electrode particles, the solid phase potential in the negative electrode region and the average open circuit voltage of the negative electrode particles.

7. The method for calculating the electrochemical impedance of a battery according to claim 6, characterized in that: The polarization values ​​corresponding to different positions inside the battery include at least one of the following polarization values: the polarization value of the negative electrode liquid phase, the negative electrode electrochemical polarization value, the negative electrode diffusion polarization value, the polarization value of the diaphragm liquid phase, the polarization value of the positive electrode liquid phase, the positive electrode electrochemical polarization value and the positive electrode diffusion polarization value.

8. The method for calculating the electrochemical impedance of a battery according to claim 7, characterized in that: The obtaining polarization values ​​corresponding to different positions inside the battery according to the electric potentials corresponding to different positions inside the battery includes: Obtaining the polarization value of the negative electrode liquid phase according to the average value of the electrolyte potential in the negative electrode region and the electrolyte potential on the negative electrode current collector side; and / or, Obtaining the polarization value of the positive electrode liquid phase according to the average value of the electrolyte potential in the positive electrode region and the electrolyte potential on the positive electrode current collector side; and / or, Obtaining the polarization value of the diaphragm liquid phase according to the electrolyte potential on the negative electrode diaphragm side and the electrolyte potential on the positive electrode diaphragm side; and / or, The positive electrode electrochemical polarization value is obtained according to the average potential of the positive electrode region and the average open circuit voltage on the surface of the positive electrode particles; wherein the average potential of the positive electrode region is the average value of the difference between the electrolyte potential of the positive electrode region and the solid phase potential of the positive electrode region; and / or, The negative electrode electrochemical polarization value is obtained according to the average potential of the negative electrode region and the average open circuit voltage on the surface of the negative electrode particles; wherein the average potential of the negative electrode region is the average value of the difference between the electrolyte potential of the negative electrode region and the solid phase potential of the negative electrode region; and / or, Obtaining the negative electrode diffusion polarization value according to the electrolyte potential on the negative electrode current collector side, the average open circuit voltage on the surface of the negative electrode particles, the average value of the electrolyte potential in the negative electrode region and the average open circuit voltage of the negative electrode particles; and / or, The polarization value of the positive electrode liquid phase is obtained according to the electrolyte potential on the positive electrode current collector side, the average open circuit voltage on the surface of the positive electrode particles, the average value of the electrolyte potential in the positive electrode region and the average open circuit voltage of the positive electrode particles.

9. The method for calculating the electrochemical impedance of a battery according to claim 8, characterized in that: The design information includes at least the following information: total thickness of battery pole pieces, thickness of negative pole pieces, total mass of positive electrode, total mass of negative electrode and thickness of diaphragm; The material information includes at least the following information: material radius, and a material lithium concentration-equilibrium voltage interpolation table.

10. A battery electrochemical impedance calculation device, characterized in that: The electrochemical impedance calculation device of the battery comprises: A construction module is used to construct a P2D model corresponding to the battery; A first acquisition module, used for acquiring the electric potential corresponding to different positions inside the battery according to the P2D model; A second acquisition module, used to acquire polarization values ​​corresponding to different positions inside the battery according to the electric potentials corresponding to different positions inside the battery; A third acquisition module, used to acquire impedance values ​​corresponding to different positions inside the battery according to polarization values ​​corresponding to different positions inside the battery; The output module is used to output the impedance values ​​corresponding to different positions inside the battery.

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