Battery direct current internal resistance decomposition method, device, equipment and medium

Abstract

The embodiment of the invention discloses a battery direct-current internal resistance decomposition method, device and equipment and a medium, and relates to the technical field of batteries. The method comprises the following steps: establishing a battery geometric model according to battery design parameters, and inputting physical property parameters into the battery geometric model; performing discharge simulation according to the battery geometric model to obtain battery discharge simulation parameters, the battery discharge simulation parameters including a current density parameter and a potential parameter; and calculating decomposition internal resistance values according to the battery discharge simulation parameters, wherein the decomposition internal resistance values comprise ohmic internal resistance, electrochemical reaction internal resistance and diffusion internal resistance. In this way, a detailed battery geometric model is constructed, and high-precision calculation and decomposition of the direct-current internal resistance components of the lithium ion battery are achieved.

Description

Technical Field

[0001] The present invention relates to the field of batteries, and in particular, to a method, device, equipment and medium for decomposing the DC internal resistance of a battery. Background Art

[0002] With the continuous improvement of the requirements for battery performance, some limitations of traditional DC internal resistance measurement methods have gradually emerged. For example, although the constant current discharge method is simple and easy to implement, it can only obtain the total DC internal resistance value and cannot be further decomposed into internal resistance components from different sources; the electrochemical impedance spectroscopy (EIS) can provide more detailed frequency domain information, but the signal is weak in the low frequency band and it is difficult to accurately reflect the DC internal resistance characteristics under actual working conditions; while the experimental test method: usually takes a long time, has a high cost, and it is difficult to achieve real-time monitoring and online analysis.

[0003] Therefore, the traditional DC internal resistance measurement method has the disadvantages of low accuracy and long time consumption for the decomposition of DC internal resistance. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to overcome the deficiencies in the prior art and provide a method, device, equipment and medium for decomposing the DC internal resistance of a battery, which is used to decompose the DC internal resistance of a lithium-ion battery through a battery geometric model, achieve high-precision and fast real-time monitoring, and can also specifically decompose different components of the DC internal resistance.

[0005] The present invention provides the following technical solutions:

[0006] In a first aspect, the present invention proposes a method for decomposing the DC internal resistance of a battery, including:

[0007] Establish a battery geometric model according to the battery design parameters, and input the physical property parameters into the battery geometric model;

[0008] Perform a discharge simulation according to the battery geometric model to obtain battery discharge simulation parameters, where the battery discharge simulation parameters include current density parameters and potential parameters;

[0009] Calculate the decomposed internal resistance value according to the battery discharge simulation parameters, where the decomposed internal resistance value includes ohmic internal resistance, electrochemical reaction internal resistance and diffusion internal resistance.

[0010] In an embodiment, the calculating the decomposed internal resistance value according to the battery discharge simulation parameters includes:

[0011] Calculate the ohmic internal resistance according to the physical property parameters and the current density parameters;

[0012] Calculate the electrochemical reaction internal resistance according to the physical property parameters, the current density parameters and the potential parameters;

[0013] Calculate the diffusion resistance of lithium ions in the electrode material and the electrolyte according to the physical property parameters and the potential parameters to obtain the diffusion internal resistance.

[0014] In one embodiment, the ohmic internal resistance includes a positive electrode solid-phase ohmic internal resistance, a negative electrode solid-phase ohmic internal resistance, a positive electrode liquid-phase ohmic internal resistance, a negative electrode liquid-phase ohmic internal resistance, and a separator liquid-phase ohmic internal resistance. The current density parameters include a liquid-phase density parameter and a solid-phase density parameter. The physical property parameters include an operating current and a conductivity parameter. The conductivity parameter includes an electrode conductivity parameter and an electrolyte conductivity parameter.

[0015] The calculation of the ohmic internal resistance according to the physical property parameters and the current density parameters includes:

[0016] Based on the positive electrode domain and the negative electrode domain, perform integrations respectively according to the solid-phase density parameter and the electrode conductivity parameter to obtain a first positive electrode integration and a first negative electrode integration.

[0017] Calculate the positive electrode solid-phase ohmic internal resistance and the negative electrode solid-phase ohmic internal resistance according to the first positive electrode integration, the first negative electrode integration, and the operating current.

[0018] Based on the positive electrode domain, the negative electrode domain, and the separator domain, perform integrations respectively according to the liquid-phase density parameter and the electrolyte conductivity parameter to obtain a second positive electrode integration, a second negative electrode integration, and a second separator integration.

[0019] Calculate the positive electrode liquid-phase ohmic internal resistance, the negative electrode liquid-phase ohmic internal resistance, and the separator liquid-phase ohmic internal resistance according to the second positive electrode integration, the second negative electrode integration, the second separator integration, and the operating current.

[0020] In one embodiment, the electrochemical reaction internal resistance includes a positive electrode electrochemical reaction internal resistance and a negative electrode electrochemical reaction internal resistance. The physical property parameters further include the lithium ion transfer number, the gas constant, the temperature, the Faraday constant, and the activity coefficient. The potential parameters include the solid-phase potential, the liquid-phase potential, and the surface potential. The current density parameters include the electrochemical reaction density parameter.

[0021] The calculation of the electrochemical reaction internal resistance according to the physical property parameters, the current density parameters, and the potential parameters includes:

[0022] Based on the positive electrode domain and the negative electrode domain, perform integrations respectively according to the electrochemical reaction density parameter, the solid-phase potential, the liquid-phase potential, and the surface potential to obtain a third positive electrode integration and a third negative electrode integration.

[0023] Calculate the positive electrode electrochemical reaction internal resistance and the negative electrode electrochemical reaction internal resistance according to the third positive electrode integration, the third negative electrode integration, and the operating current.

[0024] In one embodiment, the diffusion internal resistance includes a positive solid-phase diffusion internal resistance, a negative solid-phase diffusion internal resistance, a positive liquid-phase diffusion internal resistance, a negative liquid-phase diffusion internal resistance, and a separator liquid-phase diffusion internal resistance. The potential parameter further includes an average potential. Calculating the diffusion resistance of lithium ions in the electrode material and the electrolyte according to the physical property parameter and the potential parameter to obtain the diffusion internal resistance includes:

[0025] Based on the positive electrode domain and the negative electrode domain, performing integrals respectively according to the electrochemistry reaction density parameter, the solid-phase potential, and the average potential to obtain a fourth positive electrode integral and a fourth negative electrode integral;

[0026] Calculating the positive solid-phase diffusion internal resistance and the negative solid-phase diffusion internal resistance according to the fourth positive electrode integral, the fourth negative electrode integral, and the working current;

[0027] Based on the positive electrode domain, the negative electrode domain, and the separator domain, performing integrals respectively according to the lithium ion transfer number, the gas constant, the temperature, the Faraday constant, the activity coefficient, and the liquid-phase density parameter to obtain a fifth positive electrode integral, a fifth negative electrode integral, and a fifth separator integral;

[0028] Calculating the positive liquid-phase diffusion internal resistance, the negative liquid-phase diffusion internal resistance, and the separator liquid-phase diffusion internal resistance according to the fifth positive electrode integral, the fifth negative electrode integral, the fifth separator integral, and the working current.

[0029] In one embodiment, the discharging simulation is performed according to the battery geometric model to obtain battery discharging simulation parameters, including:

[0030] Determining battery adjustment parameters according to the battery design parameters, and determining a plurality of simulation conditions according to the battery adjustment parameters;

[0031] Performing discharging simulations respectively according to the battery geometric model based on each of the simulation conditions to obtain battery discharging simulation parameters corresponding to each of the simulation conditions;

[0032] The method further includes:

[0033] Determining a target adjustment parameter from the battery adjustment parameters according to the decomposition internal resistance values corresponding to each of the simulation conditions;

[0034] Determining a battery adjustment strategy according to the target adjustment parameter, where the battery adjustment strategy is used to adjust the total value of the DC internal resistance of the battery.

[0035] In one embodiment, determining the target adjustment parameter from the battery adjustment parameters according to the decomposition internal resistance values corresponding to each of the simulation conditions includes:

[0036] Perform a sensitivity analysis on the decomposed internal resistance values corresponding to each of the simulation conditions to determine the target adjustment parameter from the battery adjustment parameters, where the target adjustment parameter is used to affect the total DC internal resistance of the battery.

[0037] In a second aspect, the present invention provides a device for decomposing the DC internal resistance of a battery, comprising:

[0038] A construction module for establishing a battery geometric model according to battery design parameters and inputting physical property parameters into the battery geometric model;

[0039] A simulation module for performing a discharge simulation according to the battery geometric model to obtain battery discharge simulation parameters, where the battery discharge simulation parameters include current density parameters and potential parameters;

[0040] A decomposition module for calculating a decomposed internal resistance value according to the battery discharge simulation parameters, where the decomposed internal resistance value includes ohmic internal resistance, electrochemical reaction internal resistance, and diffusion internal resistance.

[0041] In a third aspect, the present invention provides a computer device, comprising a memory and a processor, where the memory stores a computer program, and when the computer program is executed by the processor, it implements the method for decomposing the DC internal resistance of a battery as described in the first aspect.

[0042] In a fourth aspect, the present invention provides a computer-readable storage medium storing a computer program, and when the computer program is executed by a processor, it implements the method for decomposing the DC internal resistance of a battery as described in the first aspect.

[0043] The method, device, equipment, and medium for decomposing the DC internal resistance of a battery disclosed in the present invention establish a battery geometric model according to battery design parameters and input physical property parameters into the battery geometric model; perform a discharge simulation according to the battery geometric model to obtain battery discharge simulation parameters, where the battery discharge simulation parameters include current density parameters and potential parameters; calculate a decomposed internal resistance value according to the battery discharge simulation parameters, where the decomposed internal resistance value includes ohmic internal resistance, electrochemical reaction internal resistance, and diffusion internal resistance. In this way, a detailed battery geometric model is constructed, realizing high-precision calculation and decomposition of the components of the DC internal resistance of a lithium-ion battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] To more clearly illustrate the technical solutions of the present invention, the following will briefly introduce the drawings required for use in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as limiting the protection scope of the present invention. In each drawing, similar components are numbered similarly.

[0045] Figure 1 Shows a schematic flowchart of the method for decomposing the DC internal resistance of a battery proposed in this embodiment;

[0046] Figure 2 shows another schematic flowchart of the battery DC internal resistance decomposition method proposed in this embodiment;

[0047] Figure 3 shows a comparison schematic diagram of the ohmic internal resistance proposed in this embodiment;

[0048] Figure 4 shows a comparison schematic diagram of the electro-chemical reaction internal resistance proposed in this embodiment;

[0049] Figure 5 shows a comparison schematic diagram of the diffusion internal resistance proposed in this embodiment;

[0050] Figure 6 shows a schematic structural diagram of the battery DC internal resistance decomposition device proposed in this embodiment.

[0051] Explanation of the reference numerals in the drawings:

[0052] 600 - Battery DC internal resistance decomposition device; 601 - Construction module; 602 - Simulation module; 603 - Decomposition module. Detailed implementation manners

[0053] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0054] Generally, the components of the embodiments of the present invention described and illustrated herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0055] Hereinafter, the terms "including", "having" and their cognates that can be used in various embodiments of the present invention are only intended to indicate specific features, numbers, steps, operations, elements, components or combinations of the foregoing items, and should not be construed as first excluding the existence of one or more other features, numbers, steps, operations, elements, components or combinations of the foregoing items or increasing the possibility of one or more features, numbers, steps, operations, elements, components or combinations of the foregoing items.

[0056] In addition, the terms "first", "second", "third", etc. are only used for differentiating descriptions and cannot be understood as indicating or implying relative importance.

[0057] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which various embodiments of the present invention pertain. The terms (such as those defined in a commonly used dictionary) will be interpreted as having the same meaning as their contextual meaning in the relevant technical field and will not be interpreted as having an idealized or overly formal meaning, unless clearly defined in various embodiments of the present invention.

[0058] Embodiment 1

[0059] The embodiments of the present disclosure provide a method for decomposing the DC internal resistance of a battery, which is used to decompose the DC internal resistance of a lithium-ion battery through a battery geometric model, achieve high-precision and fast real-time monitoring, and can also specifically decompose different components of the DC internal resistance.

[0060] Please refer to Figure 1 , a method for decomposing the DC internal resistance of a battery includes steps S101 to S103, and the following is a detailed description of each step.

[0061] Step S101, establish a battery geometric model according to battery design parameters, and input physical property parameters into the battery geometric model.

[0062] In this embodiment, establishing a battery geometric model according to battery design parameters includes key components such as positive and negative electrode active material layers, separators, and current collectors. The battery geometric model adopts the most commonly used Pseudo Two-Dimensional (P2D) model for lithium-ion batteries, which can simulate the solid-phase diffusion process inside the electrode and the transport process in the liquid phase, and simultaneously consider the electrochemistry reaction kinetics. Among them, the battery design parameters are generally the actual design dimensions of the battery.

[0063] The physical property parameters generally include the specific parameters of the positive and negative electrode active materials and the property parameters of the electrolyte. After establishing the battery geometric model, input the specific parameters of the positive and negative electrode active materials (such as particle size distribution, specific surface area, porosity), and property parameters such as electrolyte viscosity, conductivity, and concentration into the battery geometric model for subsequent simulation according to the corresponding design situation.

[0064] It should be noted that the boundary conditions and initial conditions of the battery geometric model can be defined. The boundary conditions are the voltage and current boundary conditions at both ends of the battery, as well as external conditions such as environmental temperature; the initial conditions are to set the initial state of the battery under a certain specific state of charge (SOC), such as initial voltage, current density, etc.

[0065] Step S102, perform a discharge simulation according to the battery geometric model to obtain battery discharge simulation parameters, where the battery discharge simulation parameters include current density parameters and potential parameters.

[0066] In this embodiment, a discharge simulation is performed according to a preset condition based on a battery geometric model, and battery discharge simulation parameters are recorded. The battery discharge simulation parameters generally include current density parameters and potential parameters.

[0067] Exemplarily, it is set that the battery geometric model performs a simulation discharge of a certain multiple current I for 30 seconds at a certain specific SOC level, and the corresponding battery discharge simulation parameters are recorded. The voltage V at the start of the discharge can also be recorded start and the voltage V at the end of the discharge end , so as to calculate the total DC internal resistance R tot . The total DC internal resistance R tot Calculation formula: The total DC internal resistance R tot can be used to verify whether the subsequent decomposed DC internal resistance value is correct.

[0068] Step S103, calculate the decomposed internal resistance value according to the battery discharge simulation parameters, and the decomposed internal resistance value includes ohmic internal resistance, electrochemical reaction internal resistance, and diffusion internal resistance.

[0069] In this embodiment, according to the kinetic process, the battery DC internal resistance is divided into ohmic internal resistance, electrochemical reaction internal resistance, and diffusion internal resistance. Therefore, the decomposed internal resistance value is calculated according to the simulation parameters, and the decomposed internal resistance value includes ohmic internal resistance, electrochemical reaction internal resistance, and diffusion internal resistance. In this way, by using efficient simulation calculation, fast and real-time internal resistance monitoring is realized, and the change of battery performance can be detected in time under complex working conditions; at the same time, through internal resistance decomposition, a deeper understanding of the internal state of the battery is provided, making the measurement results more accurate and reliable.

[0070] Please refer to Figure 2 , in a specific embodiment, step S103 includes steps S1031 to S1032, and the following is a detailed description of each step.

[0071] Step S1031, calculate the ohmic internal resistance according to the physical property parameters and the current density parameters.

[0072] In this embodiment, the electrolyte resistance, the current collector resistance, and the resistance generated by the conduction of electrons in the active particles are calculated according to the physical property parameters and the conductivity parameters to obtain the ohmic internal resistance.

[0073] In a specific embodiment, the ohmic internal resistance includes a positive solid-phase ohmic internal resistance, a negative solid-phase ohmic internal resistance, a positive liquid-phase ohmic internal resistance, a negative liquid-phase ohmic internal resistance, and a separator liquid-phase ohmic internal resistance. The current density parameter includes a liquid-phase density parameter and a solid-phase density parameter. The physical property parameter includes a working current and a conductivity parameter. The conductivity parameter includes an electrode conductivity parameter and an electrolyte conductivity parameter. Step S1031 includes: based on the positive electrode domain and the negative electrode domain, performing integration according to the solid-phase density parameter and the electrode conductivity parameter respectively to obtain a first positive electrode integration and a first negative electrode integration; calculating the positive solid-phase ohmic internal resistance and the negative solid-phase ohmic internal resistance according to the first positive electrode integration, the first negative electrode integration, and the working current; based on the positive electrode domain, the negative electrode domain, and the separator domain, performing integration according to the liquid-phase density parameter and the electrolyte conductivity parameter respectively to obtain a second positive electrode integration, a second negative electrode integration, and a second separator integration; calculating the positive liquid-phase ohmic internal resistance, the negative liquid-phase ohmic internal resistance, and the separator liquid-phase ohmic internal resistance according to the second positive electrode integration, the second negative electrode integration, the second separator integration, and the working current.

[0074] In this embodiment, according to the position, the ohmic internal resistance can be divided into a positive solid-phase ohmic internal resistance, a negative solid-phase ohmic internal resistance, a positive liquid-phase ohmic internal resistance, a negative liquid-phase ohmic internal resistance, and a separator liquid-phase ohmic internal resistance. Among them, the solid-phase density parameter includes a solid-phase electron current density, the electrode conductivity parameter includes a solid-phase effective conductivity, the liquid-phase density parameter includes a liquid-phase ion current density, and the electrolyte conductivity parameter includes a liquid-phase effective conductivity.

[0075] Based on the positive electrode domain and the negative electrode domain, performing integration according to the solid-phase density parameter and the electrode conductivity parameter respectively to obtain a first positive electrode integration and a first negative electrode integration; further calculating the positive solid-phase ohmic internal resistance and the negative solid-phase ohmic internal resistance according to the first positive electrode integration, the first negative electrode integration, and the working current. The calculation formula is: In the formula, I is the working current, i s is the solid-phase electron current density, v eff is the solid-phase effective conductivity, x ∈ positive is used to indicate that the integration region belongs to the positive electrode domain, x ∈ negative is used to indicate that the integration region belongs to the negative electrode domain, and i is the current density and belongs to the simulation parameter.

[0076] Based on the positive electrode domain, the negative electrode domain, and the separator domain, performing integration according to the liquid-phase density parameter and the electrolyte conductivity parameter respectively to obtain a second positive electrode integration, a second negative electrode integration, and a second separator integration. Further calculating the positive liquid-phase ohmic internal resistance, the negative liquid-phase ohmic internal resistance, and the separator liquid-phase ohmic internal resistance according to the second positive electrode integration, the second negative electrode integration, the second separator integration, and the working current. The calculation formula is: wherein, i l is the liquid-phase ionic current density, k eff is the effective liquid-phase conductivity, and x ∈ separator is used to indicate that the integration region belongs to the separator domain.

[0077] Step S1032: Calculate the internal resistance of the electrochemical reaction based on the physical property parameters, the current density parameters, and the potential parameters.

[0078] In this embodiment, the internal resistance of the electrochemical reaction is calculated based on the physical property parameters, the current density parameters, and the potential parameters to obtain the resistance caused by the charge transfer process at the electrode / electrolyte interface.

[0079] In a specific embodiment, the internal resistance of the electrochemical reaction includes the internal resistance of the positive electrode electrochemical reaction and the internal resistance of the negative electrode electrochemical reaction. The potential parameters include the solid-phase potential, the liquid-phase potential, and the surface potential. The current density parameters include the electrochemical reaction density parameters. Step S1032 includes: Based on the positive electrode domain and the negative electrode domain, perform integrations respectively according to the electrochemical reaction density parameters, the solid-phase potential, the liquid-phase potential, and the surface potential to obtain a third positive electrode integration and a third negative electrode integration; Calculate the internal resistance of the positive electrode electrochemical reaction and the internal resistance of the negative electrode electrochemical reaction based on the third positive electrode integration, the third negative electrode integration, and the working current.

[0080] In this embodiment, based on the positive electrode domain and the negative electrode domain, perform integrations respectively according to the electrochemical reaction density parameters, the solid-phase potential, the liquid-phase potential, and the surface potential to obtain a third positive electrode integration and a third negative electrode integration; Calculate the internal resistance of the positive electrode electrochemical reaction and the internal resistance of the negative electrode electrochemical reaction based on the third positive electrode integration, the third negative electrode integration, and the working current. The calculation formula is:

[0081] wherein, is the solid-phase potential, is the liquid-phase potential, E surf is the surface potential of the active material.

[0082] Step S1033: Calculate the diffusion resistance of lithium ions in the electrode material and the electrolyte based on the physical property parameters and the potential parameters to obtain the diffusion internal resistance.

[0083] In this embodiment, the internal resistance corresponding to the potential drop caused by the diffusion of lithium ions inside the electrode active material and the internal resistance corresponding to the diffusion of ions in the electrolyte are calculated based on the physical property parameters and the potential parameters to obtain the diffusion internal resistance.

[0084] In a specific embodiment, the diffusion internal resistance includes a positive solid-phase diffusion internal resistance, a negative solid-phase diffusion internal resistance, a positive liquid-phase diffusion internal resistance, a negative liquid-phase diffusion internal resistance, and a separator liquid-phase diffusion internal resistance. The physical property parameters further include the lithium-ion transfer number, the gas constant, the temperature, the Faraday constant, and the activity coefficient. The potential parameter further includes the average potential. Step S1033 includes: based on the positive electrode domain and the negative electrode domain, performing integrations respectively according to the electrochemistry reaction density parameter, the solid-phase potential, and the average potential to obtain a fourth positive electrode integration and a fourth negative electrode integration; calculating the positive solid-phase diffusion internal resistance and the negative solid-phase diffusion internal resistance according to the fourth positive electrode integration, the fourth negative electrode integration, and the working current; based on the positive electrode domain, the negative electrode domain, and the separator domain, performing integrations respectively according to the lithium-ion transfer number, the gas constant, the temperature, the Faraday constant, the activity coefficient, and the liquid-phase density parameter to obtain a fifth positive electrode integration, a fifth negative electrode integration, and a fifth separator integration; calculating the positive liquid-phase diffusion internal resistance, the negative liquid-phase diffusion internal resistance, and the separator liquid-phase diffusion internal resistance according to the fifth positive electrode integration, the fifth negative electrode integration, the fifth separator integration, and the working current.

[0085] In this embodiment, based on the positive electrode domain and the negative electrode domain, integrations are performed respectively according to the electrochemistry reaction density parameter, the solid-phase potential, and the average potential to obtain a fourth positive electrode integration and a fourth negative electrode integration; the positive solid-phase diffusion internal resistance and the negative solid-phase diffusion internal resistance are calculated according to the fourth positive electrode integration, the fourth negative electrode integration, and the working current. The calculation formulas are as follows:

[0086] In the formula, E ave is the average potential of the active material, and j is the current source density, which also belongs to the simulation parameters.

[0087] Based on the positive electrode domain, the negative electrode domain, and the separator domain, integrations are performed respectively according to the lithium-ion transfer number, the gas constant, the temperature, the Faraday constant, the activity coefficient, and the current density parameter to obtain a fifth positive electrode integration, a fifth negative electrode integration, and a fifth separator integration; the positive liquid-phase diffusion internal resistance, the negative liquid-phase diffusion internal resistance, and the separator liquid-phase diffusion internal resistance are calculated according to the fifth positive electrode integration, the fifth negative electrode integration, the fifth separator integration, and the working current. The calculation formulas are as follows: t + is the lithium-ion transfer number, R is the gas constant, T is the temperature, F is the Faraday constant, C l is the electrolyte concentration, and f ± is the activity coefficient.

[0088] In a specific embodiment, step S102 includes: determining battery adjustment parameters according to the battery design parameters, and determining a plurality of simulation conditions according to the battery adjustment parameters; respectively performing discharge simulations based on each of the simulation conditions according to the battery geometric model to obtain battery discharge simulation parameters corresponding to each of the simulation conditions; the method further includes: determining target adjustment parameters from the battery adjustment parameters according to the decomposition internal resistance values corresponding to each of the simulation conditions; determining a battery adjustment strategy according to the target adjustment parameters, and the battery adjustment strategy is used to adjust the total value of the DC internal resistance of the battery.

[0089] In this embodiment, according to the requirements of battery design, key parameters affecting the DC internal resistance are selected as battery adjustment parameters, such as electrode thickness, particle size, electrolyte concentration, etc.

[0090] Further, a reasonable adjustment range is set for each battery adjustment parameter. For example, the electrode thickness ranges from 0.05 mm to 0.15 mm, the particle size ranges from 1 um to 10 um, and the electrolyte concentration ranges from 1 M to 2 M; and the battery adjustment parameters and their corresponding adjustment ranges are used as simulation conditions.

[0091] Respectively perform discharge simulations based on each of the simulation conditions according to the battery geometric model to obtain battery discharge simulation parameters corresponding to each of the simulation conditions.

[0092] Further, calculate the decomposition internal resistance values corresponding to each of the simulation conditions according to the battery discharge simulation parameters corresponding to each of the simulation conditions.

[0093] Further, determine the target adjustment parameters that have the greatest impact on the DC internal resistance from the battery adjustment parameters according to the decomposition internal resistance values corresponding to each of the simulation conditions; determine a battery adjustment strategy according to the target adjustment parameters, so that the total value of the DC internal resistance of the battery is minimized. In this way, by adjusting these design parameters, the DC internal resistance can be effectively reduced, and the battery performance and reliability can be improved.

[0094] In a specific embodiment, a sensitivity analysis is performed on the decomposition internal resistance values corresponding to each of the simulation conditions to determine the target adjustment parameters from the battery adjustment parameters, and the target adjustment parameters are used to affect the total value of the DC internal resistance of the battery.

[0095] In this embodiment, a sensitivity analysis is performed on the decomposition internal resistance values corresponding to each of the simulation conditions, analyze the influence of different battery adjustment parameters on each decomposition internal resistance value, and determine which parameters have the greatest impact on the total value of the DC internal resistance.

[0096] First, taking the battery geometric model of a lithium iron phosphate battery as an example, simulations of discharging are carried out at three temperature points of 0 °C, 20 °C, and 40 °C respectively, and the state of charge (SOC) ranges from 10% to 100%, with an interval of 10% for each SOC point; meanwhile, the constant current discharge method is adopted for the simulation method, and discharging at a certain rate is carried out for 30 seconds at each SOC point, and the initial voltage V start and the end voltage of discharge V end are recorded. The total value of the DC internal resistance and its various components (decomposed internal resistance values) are obtained through simulation calculations.

[0097] As Figure 3 、 Figure 4 and Figure 5 shown, it is known that the ohmic internal resistance is mainly composed of the electrolyte resistance and the electrode resistance, so it is less affected by temperature, but it slightly increases under low temperature conditions; the electrochemistry internal resistance is mainly caused by the charge transfer process at the electrode / electrolyte interface, and temperature has an obvious influence on it; under low temperature conditions, the electrochemistry reaction rate slows down, resulting in an increase in the electrochemistry internal resistance; under low SOC, the electrochemistry internal resistance increases with the increase of temperature due to the influence of the diffusion process; the diffusion internal resistance is mainly caused by the potential drop caused by the diffusion of lithium ions inside the electrode active material, and temperature has a very obvious influence on it; under low temperature conditions, the diffusion rate slows down, and the diffusion internal resistance increases significantly.

[0098] To further verify the accuracy of the simulation model, a detailed decomposition of the DC internal resistance was carried out under the condition of 50% SOC, and the results are shown in Table 1 below:

[0099] T(℃) 0 20 40 Ohmic internal resistance (mΩ) 0.089 0.088 0.085 Solid-phase ohmic internal resistance (mΩ) 0.017 0.017 0.016 Liquid-phase ohmic resistance (mΩ) 0.072 0.071 0.069 Solid-phase ohmic resistance - negative electrode (mΩ) 0 0 0 Solid-phase ohmic resistance - positive electrode (mΩ) 0.017 0.017 0.016 Liquid-phase ohmic resistance - negative electrode (mΩ) 0.012 0.012 0.012 Liquid-phase ohmic resistance - separator (mΩ) 0.04 0.039 0.037 Liquid-phase ohmic resistance - positive electrode (mΩ) 0.021 0.02 0.021 Electrochemical reaction internal resistance (mΩ) 2.104 2.032 1.947 Electrochemical reaction internal resistance - positive electrode (mΩ) 0.916 1.046 1.168 Electrochemical reaction internal resistance - negative electrode (mΩ) 1.189 0.985 0.779 Diffusion internal resistance (mΩ) 1.105 0.923 0.274 Solid-phase diffusion resistance (mΩ) 0.03 0.008 0.001 Liquid-phase diffusion resistance (mΩ) 1.075 0.915 0.273 Solid-phase diffusion resistance - positive electrode (mΩ) 0 0 0 Solid-phase diffusion resistance - negative electrode (mΩ) 0.03 0.008 0.001 Positive electrode liquid-phase diffusion resistance (mΩ) 0.233 0.23 0.078 Separator liquid-phase diffusion resistance (mΩ) 0.595 0.498 0.142 Negative electrode liquid-phase diffusion resistance (mΩ) 0.247 0.188 0.053 DC internal resistance (mΩ) 3.299 3.043 2.306

[0100] It can be seen from the table that the influence of temperature on each part of the internal resistance: with the increase of temperature, all types of internal resistance decrease, especially the decrease of the diffusion internal resistance is the most obvious, and the ohmic internal resistance is less affected by temperature, but there are still slight changes.

[0101] Therefore, temperature has a significant influence on the DC internal resistance of the lithium iron phosphate battery. Under low temperature conditions, the total DC internal resistance increases significantly, mainly due to the increase of the electrochemistry internal resistance and the diffusion internal resistance. This is consistent with the slowdown of the electrochemistry reaction rate and the lithium ion diffusion rate under low temperature conditions.

[0102] The influence of SOC on the DC internal resistance The change trend of the DC internal resistance at different SOC levels is also clearly shown. Especially at low SOC and high SOC, the change of the total DC internal resistance is more obvious, reflecting the changes of the internal physical and chemical processes of the battery in these states.

[0103] Second, by way of example, taking the battery geometric model of a lithium iron phosphate battery as an example, the rated capacity is 12 Ah; at room temperature (20 °C), the SOC is fixed at 50% for discharge simulation. Simulation conditions: The cathode porosity and its adjustment range are from 0.3 to 0.7, and the simulation is carried out at a growth rate of 0.1 (i.e., 0.3, 0.4, 0.5, 0.6, 0.7).

[0104] The internal resistance decomposition table is as follows in Table 2:

[0105] Positive electrode porosity 0.3 0.4 0.5 0.6 0.7 Ohmic internal resistance (mΩ) 0.087 0.088 0.088 0.088 0.088 Solid-phase ohmic internal resistance (mΩ) 0.018 0.017 0.017 0.016 0.016 Liquid-phase ohmic resistance (mΩ) 0.069 0.071 0.071 0.072 0.072 Solid-phase ohmic resistance - negative electrode (mΩ) 0 0 0 0 0 Solid-phase ohmic resistance - positive electrode (mΩ) 0.018 0.017 0.016 0.016 0.016 Liquid-phase ohmic resistance - negative electrode (mΩ) 0.012 0.012 0.012 0.012 0.012 Liquid-phase ohmic resistance - separator (mΩ) 0.039 0.039 0.039 0.039 0.039 Liquid-phase ohmic resistance - positive electrode (mΩ) 0.019 0.02 0.021 0.022 0.022 Electrochemical reaction internal resistance (mΩ) 2.063 2.032 2.016 2.008 2.002 Electrochemical reaction internal resistance - positive electrode (mΩ) 1.078 1.046 1.031 1.023 1.018 Electrochemical reaction internal resistance - negative electrode (mΩ) 0.986 0.985 0.985 0.985 0.984 Diffusion internal resistance (mΩ) 1.019 0.923 0.866 0.827 0.8 Solid-phase diffusion resistance (mΩ) 0.008 0.008 0.008 0.008 0.008 Liquid-phase diffusion resistance (mΩ) 1.011 0.915 0.858 0.819 0.792 Solid-phase diffusion resistance - positive electrode (mΩ) 0 0 0 0 0 Solid-phase diffusion resistance - negative electrode (mΩ) 0.008 0.008 0.008 0.008 0.008 Positive electrode liquid-phase diffusion resistance (mΩ) 0.325 0.23 0.172 0.135 0.109 Separator liquid-phase diffusion resistance (mΩ) 0.498 0.498 0.498 0.497 0.496 Negative electrode liquid-phase diffusion resistance (mΩ) 0.188 0.188 0.188 0.187 0.187 DC internal resistance (mΩ) 3.169 3.043 2.97 2.923 2.89

[0106] It can be seen that the simulation results show that as the cathode porosity increases, the total DC internal resistance gradually decreases, especially the decrease in the cathode liquid-phase diffusion internal resistance in the diffusion resistance is the most obvious.

[0107] Therefore, the battery adjustment strategy suggests that choosing an appropriate cathode porosity can improve the electrolyte permeability and the lithium-ion transport efficiency, thereby effectively reducing the DC internal resistance.

[0108] Third, by way of example, taking the change of the DC internal resistance of an NCA ternary lithium battery under different cathode particle diameters at 50% SOC as an example, at room temperature (20 °C), the SOC is fixed at 50% for simulation; the simulation conditions are: the cathode particle diameter and its adjustment range are from 4 um to 28 um, and the simulation is carried out at a growth rate of 4 um (i.e., 4 um, 8 um, 12 um, 16 um, 20 um, 24 um, 28 um).

[0109] The internal resistance decomposition table is as follows in Table 3:

[0110] Positive electrode particle radius (mm) 4 8 12 16 20 24 28 Ohmic internal resistance (mΩ) 0.114 0.114 0.114 0.114 0.114 0.114 0.114 Solid-phase ohmic internal resistance (mΩ) 0.041 0.041 0.041 0.04 0.04 0.04 0.04 Liquid-phase ohmic resistance (mΩ) 0.073 0.073 0.073 0.073 0.073 0.073 0.073 Solid-phase ohmic resistance - negative electrode (mΩ) 0 0 0 0 0 0 0 Solid-phase ohmic resistance - positive electrode (mΩ) 0.041 0.04 0.04 0.04 0.04 0.04 0.04 Liquid-phase ohmic resistance - negative electrode (mΩ) 0.012 0.012 0.012 0.012 0.012 0.012 0.012 Liquid-phase ohmic resistance - separator (mΩ) 0.039 0.039 0.039 0.039 0.039 0.039 0.039 Liquid-phase ohmic resistance - positive electrode (mΩ) 0.023 0.023 0.023 0.023 0.023 0.023 0.023 Electrochemical reaction internal resistance (mΩ) 2.747 4.35 5.705 6.825 7.749 8.525 9.186 Electrochemical reaction internal resistance - positive electrode (mΩ) 1.762 3.365 4.72 5.84 6.765 7.54 8.201 Electrochemical reaction internal resistance - negative electrode (mΩ) 0.985 0.985 0.985 0.985 0.985 0.985 0.985 Diffusion internal resistance (mΩ) 3.719 6.304 8.174 9.322 10.158 10.728 11.109 Solid-phase diffusion resistance (mΩ) 2.783 5.365 7.235 8.382 9.218 9.787 10.168 Liquid-phase diffusion resistance (mΩ) 0.936 0.939 0.939 0.94 0.941 0.941 0.941 Solid-phase diffusion resistance - positive electrode (mΩ) 2.775 5.357 7.227 8.373 9.21 9.779 10.16 Solid-phase diffusion resistance - negative electrode (mΩ) 0.008 0.008 0.008 0.008 0.008 0.008 0.008 Positive electrode liquid-phase diffusion resistance (mΩ) 0.253 0.257 0.257 0.258 0.259 0.259 0.259 Separator liquid-phase diffusion resistance (mΩ) 0.496 0.495 0.495 0.495 0.495 0.495 0.495 Negative electrode liquid-phase diffusion resistance (mΩ) 0.187 0.187 0.187 0.187 0.187 0.187 0.187 DC internal resistance (mΩ) 6.58 10.768 13.993 16.26 18.021 19.366 20.408

[0111] It can be seen that the simulation results show that as the particle diameter continues to increase, the DC internal resistance gradually rises, and the main reasons are the cathode electrochemical reaction internal resistance and the cathode solid-phase diffusion internal resistance.

[0112] Therefore, the battery adjustment strategy is to choose an appropriate cathode particle diameter to optimize the electrochemical reaction rate and the lithium-ion diffusion path, thereby effectively reducing the DC internal resistance.

[0113] The method for decomposing the DC internal resistance of the battery proposed in this embodiment establishes a battery geometric model according to the battery design parameters, and inputs the physical property parameters into the battery geometric model; performs a discharge simulation according to the battery geometric model to obtain battery discharge simulation parameters, and the battery discharge simulation parameters include current density parameters and potential parameters; calculates the decomposed internal resistance value according to the battery discharge simulation parameters, and the decomposed internal resistance value includes ohmic internal resistance, electrochemical reaction internal resistance and diffusion internal resistance. In this way, a detailed battery geometric model is constructed, realizing high-precision calculation and decomposition of the components of the DC internal resistance of the lithium-ion battery.

[0114] Example 2

[0115] In addition, an embodiment of the present disclosure provides a device 600 for decomposing the DC internal resistance of a battery. Please refer to Figure 6 , which includes:

[0116] A construction module 601, configured to establish a battery geometric model according to battery design parameters and input physical property parameters into the battery geometric model;

[0117] A simulation module 602, configured to perform a discharge simulation according to the battery geometric model to obtain battery discharge simulation parameters, where the battery discharge simulation parameters include current density parameters and potential parameters;

[0118] A decomposition module 603, configured to calculate a decomposed internal resistance value according to the battery discharge simulation parameters, where the decomposed internal resistance value includes an ohmic internal resistance, an electro-chemical reaction internal resistance, and a diffusion internal resistance.

[0119] Optionally, the decomposition module 603 is configured to calculate the ohmic internal resistance according to the physical property parameters and the current density parameters; calculate the electro-chemical reaction internal resistance according to the physical property parameters, the current density parameters, and the potential parameters; calculate the diffusion resistance of lithium ions in the electrode material and the electrolyte according to the physical property parameters and the potential parameters to obtain the diffusion internal resistance.

[0120] Optionally, the ohmic internal resistance includes a positive electrode solid-phase ohmic internal resistance, a negative electrode solid-phase ohmic internal resistance, a positive electrode liquid-phase ohmic internal resistance, a negative electrode liquid-phase ohmic internal resistance, and a separator liquid-phase ohmic internal resistance. The current density parameters include a liquid-phase density parameter and a solid-phase density parameter. The physical property parameters include a working current and conductivity parameters, and the conductivity parameters include electrode conductivity parameters and electrolyte conductivity parameters. The decomposition module 603 is configured to, based on a positive electrode domain and a negative electrode domain, perform integration according to the solid-phase density parameter and the electrode conductivity parameters respectively to obtain a first positive electrode integration and a first negative electrode integration; calculate the positive electrode solid-phase ohmic internal resistance and the negative electrode solid-phase ohmic internal resistance according to the first positive electrode integration, the first negative electrode integration, and the working current; based on the positive electrode domain, the negative electrode domain, and the separator domain, perform integration according to the liquid-phase density parameter and the electrolyte conductivity parameters respectively to obtain a second positive electrode integration, a second negative electrode integration, and a second separator integration; calculate the positive electrode liquid-phase ohmic internal resistance, the negative electrode liquid-phase ohmic internal resistance, and the separator liquid-phase ohmic internal resistance according to the second positive electrode integration, the second negative electrode integration, the second separator integration, and the working current.

[0121] Optionally, the internal resistance of the electrochemical reaction includes the internal resistance of the positive electrode electrochemical reaction and the internal resistance of the negative electrode electrochemical reaction. The physical property parameters further include the lithium ion transfer number, the gas constant, the temperature, the Faraday constant, and the activity coefficient. The potential parameters include the solid phase potential, the liquid phase potential, and the surface potential. The current density parameter includes the electrochemical reaction density parameter. The decomposition module 603 is configured to perform integration based on the positive electrode domain and the negative electrode domain respectively according to the electrochemical reaction density parameter, the solid phase potential, the liquid phase potential, and the surface potential to obtain a third positive electrode integration and a third negative electrode integration; and calculate the internal resistance of the positive electrode electrochemical reaction and the internal resistance of the negative electrode electrochemical reaction based on the third positive electrode integration, the third negative electrode integration, and the working current.

[0122] Optionally, the diffusion internal resistance includes the positive electrode solid phase diffusion internal resistance, the negative electrode solid phase diffusion internal resistance, the positive electrode liquid phase diffusion internal resistance, the negative electrode liquid phase diffusion internal resistance, and the separator liquid phase diffusion internal resistance. The potential parameters further include the average potential. The decomposition module 603 is configured to perform integration based on the positive electrode domain and the negative electrode domain respectively according to the electrochemical reaction density parameter, the solid phase potential, and the average potential to obtain a fourth positive electrode integration and a fourth negative electrode integration; calculate the positive electrode solid phase diffusion internal resistance and the negative electrode solid phase diffusion internal resistance based on the fourth positive electrode integration, the fourth negative electrode integration, and the working current; perform integration based on the positive electrode domain, the negative electrode domain, and the separator domain respectively according to the lithium ion transfer number, the gas constant, the temperature, the Faraday constant, the activity coefficient, and the liquid phase density parameter to obtain a fifth positive electrode integration, a fifth negative electrode integration, and a fifth separator integration; and calculate the positive electrode liquid phase diffusion internal resistance, the negative electrode liquid phase diffusion internal resistance, and the separator liquid phase diffusion internal resistance based on the fifth positive electrode integration, the fifth negative electrode integration, the fifth separator integration, and the working current.

[0123] Optionally, the simulation module 602 is configured to determine battery adjustment parameters according to the battery design parameters, and determine a plurality of simulation conditions according to the battery adjustment parameters; perform discharge simulation respectively according to the battery geometric model based on each of the simulation conditions to obtain battery discharge simulation parameters corresponding to each of the simulation conditions;

[0124] The device further includes a processing module configured to determine target adjustment parameters from the battery adjustment parameters according to the decomposition internal resistance values corresponding to each of the simulation conditions; and determine a battery adjustment strategy according to the target adjustment parameters, where the battery adjustment strategy is used to adjust the total value of the DC internal resistance of the battery.

[0125] Optionally, the processing module is configured to perform a sensitivity analysis on the decomposition internal resistance values corresponding to each of the simulation conditions to determine the target adjustment parameters from the battery adjustment parameters, where the target adjustment parameters are used to affect the total value of the DC internal resistance of the battery.

[0126] The device provided by an embodiment of the present disclosure can execute the steps of the battery DC internal resistance decomposition method provided in Embodiment 1. To avoid repetition, details are not elaborated herein.

[0127] The battery DC internal resistance decomposition device proposed in this embodiment establishes a battery geometric model according to battery design parameters, and inputs physical property parameters into the battery geometric model; performs a discharge simulation according to the battery geometric model to obtain battery discharge simulation parameters, where the battery discharge simulation parameters include current density parameters and potential parameters; calculates a decomposed internal resistance value according to the battery discharge simulation parameters, and the decomposed internal resistance value includes ohmic internal resistance, electrochemical reaction internal resistance, and diffusion internal resistance. In this way, a detailed battery geometric model is constructed, realizing high-precision calculation and decomposition of the components of the DC internal resistance of a lithium-ion battery.

[0128] Embodiment 3

[0129] In addition, an embodiment of the present disclosure provides a computer device, including a memory and a processor. The memory stores a computer program, and when the computer program is executed by the processor, it implements the battery DC internal resistance decomposition method described in Embodiment 1.

[0130] The device provided by an embodiment of the present disclosure can execute the steps of the battery DC internal resistance decomposition method provided in Embodiment 1. To avoid repetition, details are not elaborated herein.

[0131] Embodiment 4

[0132] An embodiment of the present disclosure proposes a computer-readable storage medium that stores a computer program, and when the computer program is executed by a processor, it implements the battery DC internal resistance decomposition method described in Embodiment 1 of this disclosure.

[0133] In this embodiment, the computer-readable storage medium can be a read-only memory (ROM for short), a random access memory (RAM for short), a magnetic disk, or an optical disc, etc.

[0134] The computer-readable storage medium provided in this embodiment can implement the battery DC internal resistance decomposition method provided in Embodiment 1. To avoid repetition, details are not elaborated herein.

[0135] In all the examples shown and described here, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values.

[0136] It should be noted that: similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0137] The above-described embodiments merely represent several implementation manners of the present invention. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all fall within the protection scope of the present invention.

Claims

1. A method for decomposing the DC internal resistance of a battery, characterized in that: include: Establishing a battery geometric model according to battery design parameters, and inputting physical property parameters into the battery geometric model; Perform discharge simulation according to the battery geometric model to obtain battery discharge simulation parameters, wherein the battery discharge simulation parameters include current density parameters and potential parameters; The decomposition internal resistance value is calculated according to the battery discharge simulation parameters, and the decomposition internal resistance value includes ohmic internal resistance, electrochemical reaction internal resistance and diffusion internal resistance.

2. The method for decomposing the DC internal resistance of a battery according to claim 1, characterized in that: The step of calculating the decomposed internal resistance value according to the battery discharge simulation parameter includes: Calculate the ohmic internal resistance according to the physical property parameter and the current density parameter; The electrochemical reaction internal resistance is calculated according to the physical property parameter, the current density parameter and the potential parameter; The diffusion resistance of lithium ions in the electrode material and the electrolyte is calculated according to the physical property parameters and the potential parameters to obtain the diffusion internal resistance.

3. The method for decomposing the DC internal resistance of a battery according to claim 2, characterized in that: The ohmic internal resistance includes the positive electrode solid phase ohmic internal resistance, the negative electrode solid phase ohmic internal resistance, the positive electrode liquid phase ohmic internal resistance, the negative electrode liquid phase ohmic internal resistance and the diaphragm liquid phase ohmic internal resistance, the current density parameter includes the liquid phase density parameter and the solid phase density parameter, the physical property parameters include the working current and the conductivity parameter, and the conductivity parameter includes the electrode conductivity parameter and the electrolyte conductivity parameter; The step of calculating the ohmic internal resistance according to the physical property parameter and the current density parameter comprises: Based on the positive electrode domain and the negative electrode domain, integrating according to the solid phase density parameter and the electrode conductivity parameter respectively to obtain a first positive electrode integral and a first negative electrode integral; The positive electrode solid phase ohmic internal resistance and the negative electrode solid phase ohmic internal resistance are calculated according to the first positive electrode integral, the first negative electrode integral and the working current; Based on the positive electrode domain, the negative electrode domain and the separator domain, integrating according to the liquid phase density parameter and the electrolyte conductivity parameter respectively to obtain a second positive electrode integral, a second negative electrode integral and a second separator integral; The positive electrode liquid phase ohmic internal resistance, the negative electrode liquid phase ohmic internal resistance and the diaphragm liquid phase ohmic internal resistance are calculated according to the second positive electrode integral, the second negative electrode integral, the second diaphragm integral and the working current.

4. The method for decomposing the DC internal resistance of a battery according to claim 3, characterized in that: The electrochemical reaction internal resistance includes the positive electrode electrochemical reaction internal resistance and the negative electrode electrochemical reaction internal resistance, the physical property parameters also include the lithium ion transfer number, gas constant, temperature, Faraday constant and activity coefficient, the potential parameters include solid phase potential, liquid phase potential and surface potential, and the current density parameters include electrochemical reaction density parameters; The step of calculating the electrochemical reaction internal resistance according to the physical property parameter, the current density parameter and the potential parameter comprises: Based on the positive electrode domain and the negative electrode domain, integrating the electrochemical reaction density parameter, the solid phase potential, the liquid phase potential and the surface potential respectively to obtain a third positive electrode integral and a third negative electrode integral; The positive electrode electrochemical reaction internal resistance and the negative electrode electrochemical reaction internal resistance are calculated according to the third positive electrode integral, the third negative electrode integral and the working current.

5. The method for decomposing the DC internal resistance of a battery according to claim 4, characterized in that: The diffusion internal resistance includes the positive electrode solid phase diffusion internal resistance, the negative electrode solid phase diffusion internal resistance, the positive electrode liquid phase diffusion internal resistance, the negative electrode liquid phase diffusion internal resistance and the diaphragm liquid phase diffusion internal resistance, the potential parameter also includes the average potential, and the diffusion resistance of lithium ions in the electrode material and the electrolyte is calculated according to the physical property parameters and the potential parameters to obtain the diffusion internal resistance, including: Based on the positive electrode domain and the negative electrode domain, integrating according to the electrochemical reaction density parameter, the solid phase potential and the average potential, respectively, to obtain a fourth positive electrode integral and a fourth negative electrode integral; The positive electrode solid phase diffusion internal resistance and the negative electrode solid phase diffusion internal resistance are calculated according to the fourth positive electrode integral, the fourth negative electrode integral and the working current; Based on the positive electrode domain, the negative electrode domain and the separator domain, integrating the lithium ion transfer number, the gas constant, the temperature, the Faraday constant, the activity coefficient and the liquid phase density parameter respectively to obtain a fifth positive electrode integral, a fifth negative electrode integral and a fifth separator integral; The positive electrode liquid phase diffusion internal resistance, the negative electrode liquid phase diffusion internal resistance and the membrane liquid phase diffusion internal resistance are calculated according to the fifth positive electrode integral, the fifth negative electrode integral, the fifth diaphragm integral and the working current.

6. The method for decomposing the DC internal resistance of a battery according to claim 1, characterized in that: The performing discharge simulation according to the battery geometric model to obtain battery discharge simulation parameters includes: Determining a battery adjustment parameter according to the battery design parameter, and determining a plurality of simulation conditions according to the battery adjustment parameter; Based on each of the simulation conditions, discharge simulation is performed according to the battery geometric model to obtain battery discharge simulation parameters corresponding to each of the simulation conditions; The method further comprises: Determining a target adjustment parameter from the battery adjustment parameters according to the decomposed internal resistance value corresponding to each of the simulation conditions; A battery adjustment strategy is determined according to the target adjustment parameter, and the battery adjustment strategy is used to adjust the total DC internal resistance of the battery.

7. The method for decomposing the DC internal resistance of a battery according to claim 6, characterized in that: The step of determining a target adjustment parameter from the battery adjustment parameters according to the decomposed internal resistance value corresponding to each of the simulation conditions includes: A sensitivity analysis is performed on the decomposed internal resistance values ​​corresponding to each of the simulation conditions to determine the target adjustment parameter from the battery adjustment parameters, and the target adjustment parameter is used to influence the total DC internal resistance value of the battery.

8. A battery DC internal resistance decomposition device, characterized in that: include: A construction module, used to establish a battery geometric model according to battery design parameters, and input physical property parameters into the battery geometric model; A simulation module, used to perform discharge simulation according to the battery geometric model to obtain battery discharge simulation parameters, wherein the battery discharge simulation parameters include current density parameters and potential parameters; The decomposition module is used to calculate the decomposition internal resistance value according to the battery discharge simulation parameters, and the decomposition internal resistance value includes ohmic internal resistance, electrochemical reaction internal resistance and diffusion internal resistance.

9. A computer device, characterized in that: The method comprises a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the method for decomposing the direct current internal resistance of a battery according to any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium, characterized in that: A computer program is stored therein, and when the computer program is executed by a processor, the method for decomposing the direct current internal resistance of a battery as claimed in any one of claims 1 to 7 is implemented.

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