Electrochemical parameter determination method and device of battery, equipment, medium and product

Abstract

The invention discloses a method, a device and equipment for determining electrochemical parameters of a battery, a medium and a product. The method comprises the following steps: acquiring an electrochemical impedance frequency spectrum of the battery; constructing an electrochemical model, wherein the electrochemical model is obtained by adding an electric double-layer capacitance model on the basis of the pseudo two-dimensional model; inputting an electrochemical parameter initial value into the electrochemical model, applying a sinusoidal signal with a preset frequency, and simulating a battery electrochemical experiment process to obtain a simulation voltage value and a simulation current value; performing fitting calculation processing on the simulation voltage value and the simulation current value to obtain a simulation impedance value; and performing iterative adjustment on the initial value of the electrochemical parameter according to the test impedance value and the simulation impedance value to obtain a target value of the electrochemical parameter. According to the scheme, the electrochemical parameters of the battery can be directly obtained by using the pseudo two-dimensional model and the electric double-layer capacitance model, and influences of different physical and chemical processes are distinguished through impedance analysis, so that the accuracy of electrochemical parameter calculation is improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a method, device, equipment, medium and product for determining electrochemical parameters of a battery. Background Art

[0002] With the rapid development of modern electronic devices, batteries, as key components for energy storage and conversion, have been increasingly used in various fields. The electrochemical performance of batteries refers to the characteristics that describe the battery's ability to convert energy and store electrical energy in chemical reactions. By studying the electrochemical performance of batteries, it is easy to understand key parameters such as battery energy conversion efficiency, cycle life, and storage capacity. In order to optimize battery design, improve battery performance, and extend battery life, it is particularly important to study how to determine battery electrochemical parameters.

[0003] At present, one method in the related art is to use a physics-based pseudo-two-dimensions (P2D) model to calculate and fit the charge and discharge curve, thereby simulating the electrochemical behavior of the battery during the charge and discharge process to obtain the electrochemical parameters of the battery; however, this method only uses the change information of the time domain voltage, so that the determined electrochemical parameters are not unique, resulting in low accuracy of the determined electrochemical parameters. In another method, the model used to analyze the impedance frequency spectrum is mainly an equivalent circuit model, but the model has low accuracy and cannot directly obtain the electrochemical parameters of the battery. Summary of the invention

[0004] The purpose of this application is to provide a method, device, equipment, medium and product for determining the electrochemical parameters of a battery.

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

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

[0007] Obtaining an electrochemical impedance frequency spectrum of the battery; the electrochemical impedance frequency spectrum is obtained by applying a sinusoidal signal of a preset frequency to the battery under experimental conditions, and the electrochemical impedance frequency spectrum includes test impedance values ​​at different preset frequencies;

[0008] Constructing an electrochemical model of a battery; the electrochemical model is obtained by adding a double-layer capacitance model to a pseudo-two-dimensional model, and the electrochemical model is used to simulate the electrochemical reaction process inside the battery;

[0009] Inputting the initial value of the electrochemical parameter into the electrochemical model and applying the sinusoidal signal of the preset frequency to simulate the battery electrochemical experiment process to obtain the simulated voltage value and the simulated current value;

[0010] Performing fitting calculation processing on the simulated voltage value and the simulated current value to obtain a simulated impedance value;

[0011] The initial value of the electrochemical parameter is iteratively adjusted according to the test impedance value and the simulation impedance value to obtain a target value of the electrochemical parameter.

[0012] Optionally, the iterative adjustment of the initial value of the electrochemical parameter according to the test impedance value and the simulation impedance value to obtain a target value of the electrochemical parameter specifically includes:

[0013] Comparing the test impedance value with the simulated impedance value to obtain a comparison result;

[0014] The initial value of the electrochemical parameter is iteratively adjusted according to the comparison result until the error between the test impedance value and the simulation impedance value is less than a preset threshold value, and the electrochemical parameter value corresponding to the error being less than the preset threshold value is used as the electrochemical parameter target value.

[0015] Optionally, iteratively adjusting the initial value of the electrochemical parameter according to the comparison result until the error between the test impedance value and the simulation impedance value is less than a preset threshold, and taking the electrochemical parameter value corresponding to when the error is less than the preset threshold as the electrochemical parameter target value, specifically includes:

[0016] When the comparison result indicates that the error between the test impedance value and the simulation impedance value is not less than a preset threshold, the initial value of the electrochemical parameter is corrected by using a simulated annealing algorithm to obtain an updated value of the electrochemical parameter;

[0017] Inputting the electrochemical parameter update value into the electrochemical model and applying the sinusoidal signal of the preset frequency to simulate the battery electrochemical experiment process to obtain an updated voltage value and an updated current value;

[0018] Performing fitting calculation processing on the updated voltage value and the updated current value to obtain an updated impedance value;

[0019] When the error between the test impedance value and the updated impedance value is less than the preset threshold, the electrochemical parameter update value is used as the electrochemical parameter target value.

[0020] Optionally, iteratively adjusting the initial value of the electrochemical parameter according to the comparison result until the error between the test impedance value and the simulation impedance value is less than a preset threshold, and taking the electrochemical parameter value corresponding to when the error is less than the preset threshold as the electrochemical parameter target value, comprises:

[0021] When the comparison result indicates that the error between the test impedance value and the simulation impedance value is less than a preset threshold, the initial value of the electrochemical parameter is used as the target value of the electrochemical parameter.

[0022] Optionally, the electrochemical parameter target value includes at least one of the following: electrochemical reaction rate, solid phase diffusion coefficient, electrolyte concentration distribution and double layer capacitance of the battery.

[0023] Optionally, the test impedance value includes an imaginary part of the test impedance and a real part of the test impedance; obtaining the electrochemical impedance frequency spectrum of the battery specifically includes:

[0024] Obtain the test voltage and current values ​​of the battery;

[0025] Performing fitting processing on the test voltage value to obtain a voltage phase value and a voltage amplitude corresponding to the test voltage value, and performing fitting processing on the test current value to obtain a current phase value and a current amplitude corresponding to the test current value;

[0026] The imaginary part of the test impedance and the real part of the test impedance are obtained according to the voltage phase value, the voltage amplitude, the current phase value and the current amplitude.

[0027] In a second aspect, the present application provides a device for determining electrochemical parameters of a battery, the device for determining electrochemical parameters of a battery comprising:

[0028] An acquisition module, used for acquiring an electrochemical impedance frequency spectrum of a battery; the electrochemical impedance frequency spectrum is obtained by applying a sinusoidal signal of a preset frequency to the battery under experimental conditions, and the electrochemical impedance frequency value includes test impedance values ​​at different preset frequencies;

[0029] A construction module, used to obtain and construct an electrochemical model; the electrochemical model is obtained by adding a double-layer capacitance model to the pseudo-two-dimensional model, and the electrochemical model is used to simulate the electrochemical reaction process inside the battery;

[0030] A determination module, used to input the initial value of the electrochemical parameter into the electrochemical model and apply the sinusoidal signal of the preset frequency to simulate the battery electrochemical experiment process to obtain a simulated voltage value and a simulated current value;

[0031] A processing module, used for performing fitting calculation processing on the simulated voltage value and the simulated current value to obtain a simulated impedance value;

[0032] The adjustment module is used to iteratively adjust the initial value of the electrochemical parameter according to the test impedance value and the simulation impedance value to obtain the target value of the electrochemical parameter.

[0033] 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 method for determining the electrochemical parameters of a battery described in any one of the above.

[0034] 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 determining the electrochemical parameters of a battery as described in any one of the above.

[0035] In a fifth aspect, the present application provides a computer program product, comprising a computer program, which, when executed by a processor, implements the steps of the method for determining the electrochemical parameters of a battery as described in any one of the above.

[0036] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0037] The present application provides a method, device, equipment, medium and product for determining the electrochemical parameters of a battery. The method obtains the electrochemical impedance frequency spectrum of the battery, which includes test impedance values ​​at different preset frequencies, and then constructs an electrochemical model of the battery. The electrochemical model is used to simulate the electrochemical reaction process inside the battery, and inputs the initial values ​​of the electrochemical parameters into the electrochemical model and applies a sinusoidal signal of a preset frequency to simulate the electrochemical experiment process of the battery to obtain simulated voltage values ​​and simulated current values. The simulated voltage values ​​and simulated current values ​​are fitted and calculated to obtain simulated impedance values. According to the test impedance values ​​and the simulated impedance values, the initial values ​​of the electrochemical parameters are iteratively adjusted to obtain target values ​​of the electrochemical parameters. Compared with the prior art, the present technical solution, on the one hand, obtains the electrochemical impedance frequency spectrum of the battery including the test impedance value, providing good reference information for the subsequent comparison process of the simulation impedance value; on the other hand, the electrochemical parameters of the battery can be directly obtained through the pseudo two-dimensional model, and the double-layer capacitance model is added to more accurately describe the electrochemical process of the battery. After applying a sinusoidal signal of a preset frequency, the electrochemical impedance frequency spectrum of the battery is fitted, which is convenient for determining the simulation impedance value, and then according to the test impedance value and the simulation impedance value, the initial value of the electrochemical parameter is iteratively adjusted to obtain a unique target value of the electrochemical parameter. The impedance information in the frequency domain is comprehensively considered, the effects of different parameters are distinguished, the situation of multiple parameter solutions is avoided, and the accuracy of the electrochemical parameter calculation is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] 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.

[0039] Figure 1 A system environment diagram of a system for determining electrochemical parameters of a battery in one embodiment of the present application;

[0040] Figure 2 A schematic diagram of a flow chart of a method for determining electrochemical parameters of a battery provided in one embodiment of the present application;

[0041] Figure 3 A flowchart of a method for determining an imaginary part of a test impedance and a real part of a test impedance provided by an embodiment of the present application;

[0042] Figure 4 A schematic diagram of a flow chart of a method for iteratively adjusting an initial value of an electrochemical parameter provided in one embodiment of the present application;

[0043] Figure 5 A schematic flow chart of a method for determining electrochemical parameters of a battery provided in another embodiment of the present application;

[0044] Figure 6 A schematic diagram of functional modules of a device for determining electrochemical parameters of a battery provided in one embodiment of the present application;

[0045] Figure 7 A schematic diagram of the structure of a computer device provided in one embodiment of the present application. DETAILED DESCRIPTION

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

[0047] In 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.

[0048] The method for determining the electrochemical parameters of a battery provided in the embodiments of the present application can be applied to Figure 1In the application environment shown. Among them, the terminal 102 communicates with the server 104 through the network. The data storage system can store the data that the server 104 needs to process. The data storage system can be set up separately, integrated on the server 104, or placed on the cloud or other servers. The terminal 102 can send the electrochemical impedance frequency spectrum of the battery to the server 104. After receiving the electrochemical impedance frequency spectrum, the server 104 constructs an electrochemical model, and then inputs the initial value of the electrochemical parameter into the electrochemical model and applies a sinusoidal signal of a preset frequency to simulate the battery electrochemical experimental process to obtain a simulated impedance value, and then iteratively adjusts the initial value of the electrochemical parameter according to the test impedance value and the simulated impedance value to obtain the target value of the electrochemical parameter. The server 104 can feedback the obtained target value of the electrochemical parameter to the terminal 102. In addition, in some embodiments, the method for determining the electrochemical parameters of the battery can also be implemented separately by the server 104 or the terminal 102. For example, the terminal 102 can directly iteratively adjust the initial value of the electrochemical parameter for the test impedance value and the simulated impedance value of the battery to obtain the target value of the electrochemical parameter. The server 104 can also obtain the test impedance value and the simulated impedance value of the battery from the data storage system, and determine the electrochemical parameters for the test impedance value and the simulated impedance value of the battery. The above electrochemical model can be pre-stored in the server 104 or the terminal 102.

[0049] The terminal 102 may be, but is not limited to, various desktop computers, laptop computers, smart phones, tablet computers, IoT devices, and portable wearable devices. The IoT devices may be smart speakers, smart TVs, smart air conditioners, smart vehicle-mounted devices, etc. The portable wearable devices may be smart watches, smart bracelets, head-mounted devices, etc. The server 104 may be implemented as an independent server or a server cluster consisting of multiple servers, or may be a cloud server.

[0050] In an exemplary embodiment, Figure 2 As shown, a method for determining the electrochemical parameters of a battery is provided. The method is executed by a computer device, and can be executed by a computer device such as a terminal or a server alone, or by a terminal and a server together. In the embodiment of the present application, the method is applied to Figure 1 The server in the example is used to illustrate, including the following steps 201 to 205. Among them:

[0051] Step 201, obtaining an electrochemical impedance frequency spectrum of the battery; the electrochemical impedance frequency spectrum is obtained by applying a sinusoidal signal of a preset frequency to the battery under experimental conditions, and the electrochemical impedance frequency value includes test impedance values ​​at different preset frequencies.

[0052] It should be noted that the experimental conditions may include electrochemical impedance spectroscopy (EIS) test conditions. The above battery may be a lithium ion battery or other types of batteries.

[0053] It is understood that the electrochemical impedance spectroscopy (EIS) test is an important means of measuring battery performance. It analyzes the electrochemical performance of the battery by applying a series of sinusoidal voltage (or current) disturbance signals of preset frequencies to the battery system and recording the corresponding current (or voltage) response signals. The preset frequency may include multiple different frequencies, which may be customized according to actual needs, for example, 0.01Hz-1kHz.

[0054] During the experiment, an electrochemical workstation can usually be used to provide a sinusoidal excitation signal, and the positive electrode of the power battery is used as the working electrode, and the negative electrode is used as the counter electrode. The electrochemical impedance spectroscopy (EIS) test of the battery is performed using the two-electrode method. The test method may include a constant potential method and a constant current method, which is a composite voltage signal obtained by applying a constant voltage and a sinusoidal signal with a certain amplitude, and measuring the AC current response of the battery system at the same time. The constant current method is to apply a composite current signal composed of a DC current and a sinusoidal current signal with a certain amplitude as an excitation to the power battery, and measure the voltage signal response of the power battery system at the same time.

[0055] Optionally, a sinusoidal signal of a preset frequency is applied to the battery in an experimental environment to generate disturbance interference to the battery, thereby obtaining a test voltage value and a test current value of the battery and sending them to a computer device, so that the computer device obtains the test voltage value and the test current value of the battery, and performs fitting calculation processing on the test voltage value and the test current value to obtain a test impedance value.

[0056] The above test impedance value includes an imaginary part of the test impedance and a real part of the test impedance.

[0057] Specifically, after obtaining the test voltage value and the test current value, the Levenberg-Marquardt method can be used to fit the test voltage value and the test current value to obtain the corresponding voltage amplitude, voltage phase value, current amplitude and current phase value. Then, the voltage amplitude, voltage phase value, current amplitude and current phase value are calculated and processed to obtain the imaginary part of the test impedance and the real part of the test impedance.

[0058] In this embodiment, since the test voltage value and the test current value are fitted and calculated, the test impedance value can be accurately determined, which provides good data reference information for the subsequent comparison process of the simulation impedance value.

[0059] Step 202, constructing an electrochemical model; the electrochemical model is obtained by adding a double-layer capacitance model to the pseudo-two-dimensional model, and the electrochemical model is used to simulate the electrochemical reaction process inside the battery.

[0060] It should be noted that after obtaining the electrochemical impedance frequency spectrum of the battery, an electrochemical model of the battery is constructed. The electrochemical model is used to characterize the physical and chemical process of the battery. It can include a pseudo-two-dimensions (P2D) model and a double-layer capacitance model. The electrochemical reaction process inside the battery is simulated by these two models. The equation of the constructed double-layer capacitance model can be expressed by the following formula:

[0061]

[0062] Where a is the surface area to volume ratio of the electrode particles, F is the Faraday constant, and i n，f is the particle surface ion flux, C is the double layer capacitance, Φ1 is the solid phase potential, Φ2 is the liquid phase potential, ∈ is the liquid phase volume fraction, D eff is the effective diffusion coefficient, is the transfer coefficient and i2 is the electrolyte current.

[0063] The function of the double-layer capacitor model is mainly to simulate the impedance frequency spectrum test more accurately. The principle of double-layer capacitor is based on inserting two electrodes in the electrolyte and applying a voltage between them that is less than the decomposition voltage of the electrolyte solution. This process allows the positive and negative particles of the electrolyte to quickly run toward the electrodes under the action of the electric field and form a tight charge layer on the surface of the electrode, namely the double layer. The double layer is a phenomenon, and the size of the double-layer capacitor may affect the voltage and power of instantaneous discharge.

[0064] The electrochemical model constructed according to the battery property parameters in this step can describe the physical and chemical processes in the battery. By fitting the electrochemical impedance power spectrum, the electrochemical parameters of the battery can be directly obtained without the need for additional charge and discharge curve fitting steps.

[0065] Step 203 , inputting initial values ​​of electrochemical parameters into the electrochemical model and applying a sinusoidal signal of a preset frequency to simulate the battery electrochemical experiment process to obtain a simulated voltage value and a simulated current value.

[0066] After the electrochemical model is constructed, the initial values ​​of the electrochemical parameters can be obtained, and then the initial values ​​of the electrochemical parameters can be input into the electrochemical model to obtain the electrochemical model after the electrochemical parameters are input, so as to simulate the electrochemical experimental process of the battery through the electrochemical model after the electrochemical parameters, and then a sinusoidal signal of a preset power is applied to the battery to output the simulated voltage value and simulated current value of the battery. Among them, the sinusoidal signal can be a sinusoidal voltage signal of a preset frequency, or it can be a sinusoidal current signal, and the preset frequency can be different frequencies, which are customized according to actual needs.

[0067] It can be understood that the above-mentioned simulated voltage value refers to the value obtained by simulating the battery electrochemical experimental process through an electrochemical model and applying a sinusoidal voltage signal of a preset frequency, and the simulated current value refers to the value obtained by simulating the battery electrochemical experimental process through an electrochemical model and applying a sinusoidal current signal of a preset frequency.

[0068] Among them, the target value of electrochemical parameters includes at least one of the following: the electrochemical reaction rate, solid phase diffusion coefficient, electrolyte concentration distribution and double layer capacitance of the battery. The electrochemical reaction rate of the battery is easily affected by many factors, including the properties of the electrolyte solution, electrode materials, and reaction conditions. The electrochemical reaction rate directly affects the performance of the battery, such as charging and discharging speed, energy conversion efficiency, etc. The solid phase diffusion coefficient reflects the mobility of lithium ions in the positive and negative electrode materials of the battery, which directly affects the battery's charge and discharge efficiency, energy density and overall performance.

[0069] Step 204, performing fitting calculation processing on the simulated voltage value and the simulated current value to obtain a simulated impedance value.

[0070] Specifically, the above-mentioned simulated impedance value may include an imaginary part of the simulated impedance and a real part of the simulated impedance. After obtaining the simulated voltage value and the simulated current value, the Levenberg-Marquardt method may be used to fit the simulated voltage value and the simulated current value to obtain the corresponding voltage amplitude, voltage phase value, current amplitude, and current phase value. Then, calculation processing is performed based on the voltage amplitude, voltage phase value, current amplitude, and current phase value to obtain the imaginary part of the simulated impedance and the real part of the simulated impedance.

[0071] In this embodiment, since the simulated voltage value and the simulated current value are subjected to fitting calculation processing, the simulated impedance value can be accurately determined, thereby improving the accuracy of parameter determination.

[0072] Step 205, iteratively adjusting the initial value of the electrochemical parameter according to the test impedance value and the simulation impedance value to obtain the target value of the electrochemical parameter.

[0073] Specifically, after obtaining the test impedance value and the simulation impedance value, the test impedance value can be compared with the simulation impedance value to obtain a comparison result, and then check whether the comparison result meets the preset conditions. If it does not meet the preset conditions, the initial value of the electrochemical parameter is adjusted; if it meets the preset conditions, the current electrochemical parameter value is used as the electrochemical parameter target value.

[0074] The present application provides a method for determining the electrochemical parameters of a battery, by obtaining an electrochemical impedance frequency spectrum of the battery, the electrochemical impedance frequency spectrum including test impedance values ​​at different preset frequencies, and then constructing an electrochemical model; the electrochemical model is used to simulate the electrochemical reaction process inside the battery, and the initial values ​​of the electrochemical parameters are input into the electrochemical model and a sinusoidal signal of a preset frequency is applied to simulate the electrochemical experimental process of the battery, to obtain simulated voltage values ​​and simulated current values, and the simulated voltage values ​​and simulated current values ​​are fitted and calculated to obtain simulated impedance values; the initial values ​​of the electrochemical parameters are iteratively adjusted according to the test impedance values ​​and the simulated impedance values ​​to obtain target values ​​of the electrochemical parameters. Compared with the prior art, the present technical solution, on the one hand, obtains the electrochemical impedance frequency spectrum of the battery including the test impedance value, providing good reference information for the subsequent comparison process of the simulation impedance value; on the other hand, the electrochemical parameters of the battery can be directly obtained through the pseudo two-dimensional model, and the double-layer capacitance model is added to more accurately describe the electrochemical process of the battery. After applying a sinusoidal signal of a preset frequency, the electrochemical impedance frequency spectrum of the battery is fitted, which is convenient for determining the simulation impedance value, and then according to the test impedance value and the simulation impedance value, the initial value of the electrochemical parameter is iteratively adjusted to obtain a unique target value of the electrochemical parameter. The impedance information in the frequency domain is comprehensively considered, the effects of different parameters are distinguished, the situation of multiple solutions is avoided, and the accuracy of the electrochemical parameter calculation is improved.

[0075] In another exemplary embodiment of the present application, in order to accurately determine the test impedance value of the battery, the electrochemical impedance frequency spectrum of the battery can be obtained, such as Figure 3 As shown, the above step 201 is replaced by the following steps 301 to 303:

[0076] Step 301, obtaining a test voltage value and a test current value of a battery.

[0077] Step 302, performing fitting processing on the test voltage value to obtain the voltage phase value and voltage amplitude corresponding to the test voltage value, and performing fitting processing on the test current value to obtain the current phase value and current amplitude corresponding to the test current value.

[0078] Step 303, obtaining the imaginary part of the test impedance and the real part of the test impedance according to the voltage phase value, the voltage amplitude, the current phase value and the current amplitude.

[0079] The test voltage value of the battery is obtained after a sinusoidal voltage signal of a preset frequency is applied to the battery in an experimental environment, and the test current value of the battery is obtained after a sinusoidal current signal of a preset frequency is applied to the battery in an experimental environment. The test voltage value and test current value of the battery can be obtained by the computer device from an external device, or through a blockchain or a database.

[0080] Specifically, after obtaining the test voltage value and the test current value, a voltage sine function can be constructed according to the frequency and time corresponding to the test voltage value in the frequency domain, thereby obtaining the voltage phase value and voltage amplitude corresponding to the test voltage value, and a current sine function can be constructed according to the frequency and time corresponding to the test current value in the frequency domain, thereby obtaining the current phase value and current amplitude corresponding to the test current value. The constructed sine function can be expressed by the following formula:

[0081] I = A sin(2πft+φ)+C

[0082] Among them, A is the amplitude, f is the frequency, t is the time, φ is the phase value, and C is the reference value, which is a constant. When the voltage sine function is constructed, A in the above formula is the voltage amplitude A V , φ is the voltage phase value φ V ; When the current sine function is constructed, A in the above formula is the current amplitude A I , φ is the current phase value φ I .

[0083] Furthermore, after obtaining the voltage phase value, voltage amplitude, current phase value and current amplitude, the test impedance value of the preset frequency can be calculated by the following formula:

[0084]

[0085] Among them, Z real is the real part of the test impedance, Z imag A is the imaginary part of the test impedance. V is the voltage amplitude, A I is the current amplitude, φ V is the voltage phase value, φ I is the current phase value.

[0086] Optionally, in the process of fitting the test voltage value and the test current value, the LM method may be used for fitting, and the fast Fourier transform method may be used to implement the fitting.

[0087] In this embodiment, by fitting the test voltage value and the test current value, the voltage phase value, voltage amplitude, current phase value and current amplitude can be accurately obtained, and based on the voltage phase value, voltage amplitude, current phase value and current amplitude, the imaginary part of the test impedance and the real part of the test impedance can be determined in a finer granularity, thereby improving the accuracy of the test impedance parameters and providing good reference information for the subsequent comparison process of the simulation impedance values.

[0088] In another exemplary embodiment of the present application, in order to maximize the use of the discharge capacity of the charging and discharging equipment, the target device and the maximum discharge power value corresponding to each target device can be determined from the key devices based on the load power value, the maximum sub-discharge power value and the number of key devices, such as Figure 4 As shown, the above step 206 may include the following steps 401 to 402. Among them:

[0089] Step 401, compare the test impedance value with the simulation impedance value to obtain a comparison result.

[0090] Step 402, iteratively adjust the initial value of the electrochemical parameter according to the comparison result until the error between the test impedance value and the simulation impedance value is less than a preset threshold, and use the electrochemical parameter value corresponding to the error less than the preset threshold as the electrochemical parameter target value.

[0091] After obtaining the test impedance value and the simulation impedance value, the test impedance value is compared with the simulation impedance value to obtain a comparison result, which is used to indicate whether the error between the test impedance value and the simulation impedance value is less than a preset threshold.

[0092] Specifically, the computer device can execute the specified operation in a loop until the error between the test impedance value and the simulation impedance value is less than a preset threshold. The specified operation includes: determining the current simulation impedance value according to the current value of the electrochemical parameter; wherein, when the specified operation is executed for the first time, the current value of the electrochemical parameter is the initial value of the electrochemical parameter, and when the specified operation is not executed for the first time, the current value of the electrochemical parameter is the electrochemical parameter adjustment value obtained when the specified operation was executed before; judging whether the error between the current simulation impedance value and the test impedance value is less than a preset threshold; when the error between the current impedance value and the test impedance value is not less than the preset threshold, adjusting the current value of the electrochemical parameter to obtain the electrochemical parameter adjustment value, and controlling to enter the next specified operation; when the error between the current simulation impedance value and the test impedance value is less than the preset threshold, controlling not to enter the next specified operation, and using the current value of the electrochemical parameter as the target value of the electrochemical parameter.

[0093] As an implementable method, when the comparison result indicates that the error between the test impedance value and the simulation impedance value is not less than a preset threshold, the simulated annealing algorithm is used to correct the initial value of the electrochemical parameter to obtain an updated value of the electrochemical parameter, and the updated value of the electrochemical parameter is input into the electrochemical model and a sinusoidal signal of a preset frequency is applied to simulate the electrochemical experimental process of the battery to obtain an updated voltage value and an updated current value, and the updated voltage value and the updated current value are fitted and calculated to obtain an updated impedance value, and then when the error between the test impedance value and the updated impedance value is less than a preset threshold, the updated value of the electrochemical parameter is used as the target value of the electrochemical parameter. When the comparison result indicates that the error between the test impedance value and the simulation impedance value is less than a preset threshold, the initial value of the electrochemical parameter is used as the target value of the electrochemical parameter. Among them, the updated impedance value is customized according to actual needs and can be the electrochemical parameter value obtained during the previous execution.

[0094] For example, see Figure 5 As shown, an experimental workstation is built, and sinusoidal voltage or current disturbance signals of different frequencies are applied to the battery through the experimental workstation to obtain the test voltage value and test current value output by the battery, and the test voltage value and test current value are fitted respectively to obtain the corresponding current phase value, current amplitude, voltage phase value and voltage amplitude. Then, according to the current phase value, current amplitude, voltage phase value and voltage amplitude, the real part of the test impedance and the imaginary part of the test impedance are calculated to obtain the test impedance value.

[0095] On the basis of the P2D model, a P2D model with double-layer capacitance is added to construct an electrochemical model, and then the initial values ​​of the electrochemical parameters are input into the electrochemical model and a sinusoidal signal of a preset frequency is applied to simulate the battery electrochemical experimental process to obtain the simulated voltage value and the simulated current value, and the simulated voltage value and the simulated current value are fitted to obtain the corresponding current phase value, current amplitude, voltage phase value and voltage amplitude. Then, according to the current phase value, current amplitude, voltage phase value and voltage amplitude, the real part of the simulated impedance and the imaginary part of the simulated impedance are calculated to obtain the simulated impedance value. The test impedance value obtained by the experiment is compared with the simulated impedance value obtained by simulation to determine whether the error between the test impedance value and the simulated impedance value is less than a preset threshold. When it is not less than the preset threshold, a new input value is obtained through an optimization algorithm such as a simulated annealing algorithm, and the new input value is input into the electrochemical model to simulate the experimental process to obtain a new simulated current value and a simulated voltage value, and a new simulated impedance value is obtained based on the new simulated current value and the simulated voltage value, so as to continue to determine the size of the test impedance value and the new simulated impedance value until the error is less than the preset threshold, and the corresponding input value at this time is determined as the final electrochemical parameter target value, which may include reaction rate, diffusion coefficient, double layer capacitance, etc.

[0096] In this embodiment, the initial value of the electrochemical parameter can be iteratively adjusted according to the comparison result between the test impedance value and the simulation impedance value until the error between the test impedance value and the simulation impedance value is less than a preset threshold value, and the electrochemical parameter value corresponding to the error being less than the preset threshold value is used as the electrochemical parameter target value, so that the determined electrochemical parameter target value is a unique value, avoiding the situation of multiple solutions, improving the accuracy of the electrochemical parameter calculation, and facilitating the subsequent battery design optimization based on the parameter, and accurate prediction of performance and life. For example, it can deeply analyze and optimize the battery's charge and discharge performance, and accurately predict the battery's state of charge (SOC), state of health (SOH) and remaining useful life (RUL).

[0097] Based on the same inventive concept, the embodiment of the present application also provides a battery electrochemical parameter determination device for implementing the above-mentioned battery electrochemical parameter determination method. 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 one or more battery electrochemical parameter determination devices provided below can refer to the limitations of the battery electrochemical parameter determination method above, and will not be repeated here.

[0098] In an exemplary embodiment, Figure 6 As shown, a device for determining electrochemical parameters of a battery is provided, comprising:

[0099] An acquisition module 710 is used to acquire an electrochemical impedance frequency spectrum of a battery. The electrochemical impedance frequency spectrum is obtained by applying a sinusoidal signal of a preset frequency to the battery under experimental conditions. The electrochemical impedance frequency value includes test impedance values ​​at different preset frequencies.

[0100] A construction module 720 is used to obtain and construct an electrochemical model; the electrochemical model is obtained by adding a double-layer capacitor model to the pseudo-two-dimensional model, and the electrochemical model is used to simulate the electrochemical reaction process inside the battery;

[0101] The determination module 730 is used to input the initial value of the electrochemical parameter into the electrochemical model and apply a sinusoidal signal of a preset frequency to simulate the battery electrochemical experiment process to obtain a simulated voltage value and a simulated current value;

[0102] The processing module 740 is used to perform fitting calculation processing on the simulated voltage value and the simulated current value to obtain a simulated impedance value;

[0103] The adjustment module 750 is used to iteratively adjust the initial value of the electrochemical parameter according to the test impedance value and the simulation impedance value to obtain the target value of the electrochemical parameter.

[0104] As an optional implementation, the adjustment module 750 is specifically configured to:

[0105] Compare the test impedance value with the simulated impedance value to obtain a comparison result;

[0106] The initial value of the electrochemical parameter is iteratively adjusted according to the comparison result until the error between the test impedance value and the simulation impedance value is less than a preset threshold value, and the electrochemical parameter value corresponding to the error less than the preset threshold value is used as the electrochemical parameter target value.

[0107] As an optional implementation, the adjustment module 750 is further configured to:

[0108] When the comparison result indicates that the error between the test impedance value and the simulation impedance value is not less than a preset threshold, the initial value of the electrochemical parameter is corrected by a simulated annealing algorithm to obtain an updated value of the electrochemical parameter;

[0109] Input the updated value of the electrochemical parameter into the electrochemical model and apply a sinusoidal signal of a preset frequency to simulate the battery electrochemical experimental process to obtain an updated voltage value and an updated current value;

[0110] Perform fitting calculation on the updated voltage value and the updated current value to obtain an updated impedance value;

[0111] When the error between the test impedance value and the updated impedance value is less than a preset threshold, the updated value of the electrochemical parameter is used as the target value of the electrochemical parameter.

[0112] As an optional implementation, the adjustment module 750 is further configured to:

[0113] When the comparison result indicates that the error between the test impedance value and the simulation impedance value is less than a preset threshold, the initial value of the electrochemical parameter is used as the target value of the electrochemical parameter.

[0114] As an optional implementation, the target value of the electrochemical parameter includes at least one of the following: the electrochemical reaction rate of the battery, the solid phase diffusion coefficient, the electrolyte concentration distribution and the double layer capacitance.

[0115] As an optional implementation, the acquisition module 710 is specifically configured to:

[0116] Obtain the test voltage and current values ​​of the battery;

[0117] Performing fitting processing on the test voltage value to obtain a voltage phase value and a voltage amplitude corresponding to the test voltage value, and performing fitting processing on the test current value to obtain a current phase value and a current amplitude corresponding to the test current value;

[0118] The imaginary part of the test impedance and the real part of the test impedance are obtained according to the voltage phase value, the voltage amplitude, the current phase value and the current amplitude.

[0119] Among them, by implementing this embodiment, the device obtains the electrochemical impedance frequency spectrum of the battery including the test impedance value, which provides good reference information for the subsequent comparison process of the simulation impedance value; on the other hand, the electrochemical parameters of the battery can be directly obtained through the pseudo two-dimensional model, and the double-layer capacitance model is added to more accurately describe the electrochemical process of the battery. After applying a sinusoidal signal of a preset frequency, the electrochemical impedance frequency spectrum of the battery is fitted to facilitate the determination of the simulation impedance value, and then according to the test impedance value and the simulation impedance value, the initial value of the electrochemical parameter is iteratively adjusted to obtain a unique target value of the electrochemical parameter. The impedance information in the frequency domain is comprehensively considered, the effects of different parameters are distinguished, the situation of multiple solutions is avoided, and the accuracy of the electrochemical parameter calculation is improved.

[0120] In an exemplary embodiment, a computer device is provided. The computer device may be a computer device, a server or a terminal. The internal structure diagram thereof may be as follows: Figure 7 As shown. The computer device may include 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 for determining the electrochemical parameters 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, a method for determining the electrochemical parameters of a battery is implemented.

[0121] Those skilled in the art will understand that Figure 7 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.

[0122] 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.

[0123] 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.

[0124] 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.

[0125] 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.

[0126] Those of ordinary skill 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), magnetic 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).

[0127] 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.

[0128] 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.

[0129] 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 determining electrochemical parameters of a battery, characterized in that: The method for determining the electrochemical parameters of the battery comprises: Obtaining an electrochemical impedance frequency spectrum of the battery; the electrochemical impedance frequency spectrum is obtained by applying a sinusoidal signal of a preset frequency to the battery under experimental conditions, and the electrochemical impedance frequency value includes test impedance values ​​at different preset frequencies; Constructing an electrochemical model of a battery; the electrochemical model is obtained by adding a double-layer capacitance model to a pseudo-two-dimensional model, and the electrochemical model is used to simulate the electrochemical reaction process inside the battery; Inputting the initial value of the electrochemical parameter into the electrochemical model and applying the sinusoidal signal of the preset frequency to simulate the battery electrochemical experiment process to obtain the simulated voltage value and the simulated current value; Performing fitting calculation processing on the simulated voltage value and the simulated current value to obtain a simulated impedance value; The initial value of the electrochemical parameter is iteratively adjusted according to the test impedance value and the simulation impedance value to obtain a target value of the electrochemical parameter.

2. The method for determining the electrochemical parameters of a battery according to claim 1, characterized in that: The iterative adjustment of the initial value of the electrochemical parameter according to the test impedance value and the simulation impedance value to obtain the target value of the electrochemical parameter specifically includes: Comparing the test impedance value with the simulated impedance value to obtain a comparison result; The initial value of the electrochemical parameter is iteratively adjusted according to the comparison result until the error between the test impedance value and the simulation impedance value is less than a preset threshold value, and the electrochemical parameter value corresponding to the error being less than the preset threshold value is used as the electrochemical parameter target value.

3. The method for determining the electrochemical parameters of a battery according to claim 2, characterized in that: Iteratively adjusting the initial value of the electrochemical parameter according to the comparison result until the error between the test impedance value and the simulation impedance value is less than a preset threshold, and taking the electrochemical parameter value corresponding to when the error is less than the preset threshold as the electrochemical parameter target value, specifically including: When the comparison result indicates that the error between the test impedance value and the simulation impedance value is not less than a preset threshold, the initial value of the electrochemical parameter is corrected by using a simulated annealing algorithm to obtain an updated value of the electrochemical parameter; Inputting the electrochemical parameter update value into the electrochemical model and applying the sinusoidal signal of the preset frequency to simulate the battery electrochemical experiment process to obtain an updated voltage value and an updated current value; Performing fitting calculation processing on the updated voltage value and the updated current value to obtain an updated impedance value; When the error between the test impedance value and the updated impedance value is less than the preset threshold, the electrochemical parameter update value is used as the electrochemical parameter target value.

4. The method for determining the electrochemical parameters of a battery according to claim 2, characterized in that: Iteratively adjusting the initial value of the electrochemical parameter according to the comparison result until the error between the test impedance value and the simulation impedance value is less than a preset threshold, and taking the electrochemical parameter value corresponding to when the error is less than the preset threshold as the electrochemical parameter target value, including: When the comparison result indicates that the error between the test impedance value and the simulation impedance value is less than a preset threshold, the initial value of the electrochemical parameter is used as the target value of the electrochemical parameter.

5. The method for determining the electrochemical parameters of a battery according to claim 1, characterized in that: The electrochemical parameter target value includes at least one of the following: electrochemical reaction rate, solid phase diffusion coefficient, electrolyte concentration distribution and double layer capacitance of the battery.

6. The method for determining the electrochemical parameters of a battery according to claim 1, characterized in that: The test impedance value includes the test impedance imaginary part and the test impedance real part; obtaining the electrochemical impedance frequency spectrum of the battery specifically includes: Obtain the test voltage and current values ​​of the battery; Performing fitting processing on the test voltage value to obtain a voltage phase value and a voltage amplitude corresponding to the test voltage value, and performing fitting processing on the test current value to obtain a current phase value and a current amplitude corresponding to the test current value; The imaginary part of the test impedance and the real part of the test impedance are obtained according to the voltage phase value, the voltage amplitude, the current phase value and the current amplitude.

7. A device for determining electrochemical parameters of a battery, characterized in that: The electrochemical parameter determination device of the battery comprises: An acquisition module, used for acquiring an electrochemical impedance frequency spectrum of a battery; the electrochemical impedance frequency spectrum is obtained by applying a sinusoidal signal of a preset frequency to the battery under experimental conditions, and the electrochemical impedance frequency value includes test impedance values ​​at different preset frequencies; A construction module, used to obtain and construct an electrochemical model; the electrochemical model is obtained by adding a double-layer capacitance model to the pseudo-two-dimensional model, and the electrochemical model is used to simulate the electrochemical reaction process inside the battery; A determination module, used to input the initial value of the electrochemical parameter into the electrochemical model and apply the sinusoidal signal of the preset frequency to simulate the battery electrochemical experiment process to obtain a simulated voltage value and a simulated current value; A processing module, used for performing fitting calculation processing on the simulated voltage value and the simulated current value to obtain a simulated impedance value; The adjustment module is used to iteratively adjust the initial value of the electrochemical parameter according to the test impedance value and the simulation impedance value to obtain the target value of the electrochemical parameter.

8. 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 method for determining the electrochemical parameters of a battery according to any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for determining the electrochemical parameters of a battery according to any one of claims 1 to 6 are implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method for determining the electrochemical parameters of a battery according to any one of claims 1 to 6 are implemented.

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