Current simulation method, device, equipment, storage medium and program product

Abstract

An embodiment of the present application provides a current simulation method, device, equipment, storage medium and program product. Among them, the method includes: obtaining the current collector resistance between adjacent two nodes among multiple nodes on the current collector plane of the battery cell, the charge and discharge current of the battery cell, the initial equivalent resistance and initial equivalent electric potential of each node in the first direction; based on the Kirchhoff's current law, constructing a linear equation of the electric potential of each node based on the initial equivalent resistance, initial equivalent electric potential, charge and discharge current, and the current collector resistance between adjacent two nodes among multiple nodes; solving the linear equation of the electric potential of each node to obtain the node electric potential of each node; determining the node current between adjacent two nodes on the current collector plane based on the node electric potential of each node and the current collector resistance between adjacent two nodes. It can realize the simulation of the current distribution on the current collector plane during the charge and discharge process of the battery to locate the area with abnormal current density on the current collector plane.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of batteries, and relate to, but are not limited to, a current simulation method, device, equipment, storage medium, and program product. Background Art

[0002] Currently, due to characteristics such as high energy density, long cycle life, and low self-discharge, batteries represented by lithium-ion batteries have been widely used as energy storage carriers, such as mobile phones, laptops, medical devices, electric vehicles, energy storage power stations, signal base stations, etc. To ensure the safe and efficient operation of the battery, a battery management system (BMS) is used to manage the battery, such as state estimation, fault diagnosis, and charge equalization. Currently, many BMSs adopt model-based control technologies, which require the establishment of a simulation model for the battery to be controlled.

[0003] However, since the battery is an extremely complex system, there are still problems of insufficient understanding of the mechanism in aspects such as aging in related technologies. Currently, the most widely used battery model in battery simulation is the pseudo-two-dimensional (P2D) model. However, the P2D model only reflects the electrochemical reaction process in the thickness direction and the particle radius direction of the battery, ignoring the differences in the width and height of the battery current collector, and cannot determine the current distribution at different positions on the current collector plane. Summary of the Invention

[0004] To solve the problems existing in the related technologies, the embodiments of the present application provide a current simulation method, device, equipment, storage medium, and program product, which can realize the simulation of the current distribution on the current collector plane during the charging and discharging process of the battery to locate the area where the current density on the current collector plane is abnormal.

[0005] In a first aspect, the present application provides a current simulation method. The current simulation method includes: obtaining the current collector resistance between adjacent two nodes among multiple nodes on the current collector plane of the battery cell, the charging and discharging current of the battery cell, the initial equivalent resistance and the initial equivalent electric potential of each node in the first direction; wherein, the multiple nodes are determined based on the geometric structure of the battery cell, and the first direction is the thickness direction of the current collector; based on Kirchhoff's current law, constructing a linear equation of the electric potential of each node based on the initial equivalent resistance, the initial equivalent electric potential, the charging and discharging current, and the current collector resistance between adjacent two nodes among the multiple nodes; solving the linear equation of the electric potential of each node to obtain the node electric potential of each node; and determining the node current between adjacent two nodes on the current collector plane based on the node electric potential of each node and the current collector resistance between adjacent two nodes, so as to simulate the current distribution among multiple nodes during the charging and discharging process of the battery cell.

[0006] In the above embodiments, by dividing the current collector plane in the width and height directions, a plurality of nodes are obtained. Adjacent two nodes are connected by the current collector resistance. Using Kirchhoff's current law, through the charge and discharge current of the battery cell, and the resistances of adjacent nodes on the current collector in the thickness direction and the plane direction, the electric potential of each node during the charge and discharge process can be determined. Based on the current collector resistance between adjacent nodes, the current between adjacent nodes can be obtained, and then the current distribution on the current collector plane during the charge and discharge process of the battery can be obtained. In this way, the simulation of the current distribution on the current collector plane during the charge and discharge process of the battery can be realized, the regions with abnormal current density (such as the edges and near the welding points) can be located, and the risk of local aging of the battery cell can be warned in advance; and the design of the battery cell can be optimized based on the current distribution result to obtain the most uniform current distribution scheme to improve the battery life.

[0007] In some embodiments, the current simulation method further includes: determining the battery cell voltage of the battery cell based on the node electric potential of each node; the battery cell voltage is the electric potential difference between the positive electrode tab and the negative electrode tab on the current collector plane; comparing the battery cell voltage with the cut-off voltage of the battery cell during the charge and discharge process to obtain a comparison result; in response to the comparison result indicating that the battery cell voltage does not meet the cut-off condition, determining the current equivalent resistance and the current equivalent electric potential of each node in the first direction at the current moment based on the node current between adjacent two nodes on the current collector plane at the previous moment; calculating the battery cell voltage of the battery cell at the next moment based on the current equivalent resistance and the current equivalent electric potential; in response to the battery cell voltage meeting the cut-off condition, determining the node current between adjacent two nodes at each moment before the battery cell voltage meets the cut-off condition as the current distribution between a plurality of nodes during the charge and discharge process of the battery cell.

[0008] In the above embodiments, by comparing the battery cell voltage of the battery cell with the cut-off voltage at each moment, the simulation result of the current distribution on the current collector plane at each moment during the charge and discharge process of the battery cell can be obtained. Based on this result, the heat generation situation and aging situation of each position of the battery cell can be predicted, providing a direct basis for the design of the thermal management system, thereby avoiding local overheating and prolonging the battery life; at the same time, the design of the battery cell can be optimized through this simulation result to balance the current distribution, reduce the excessive consumption of local active materials, and prolong the battery life and performance.

[0009] In some embodiments, determining the current equivalent resistance and current equivalent electric potential of each node in the first direction at the current moment based on the node current between two adjacent nodes on the current collector plane at the previous moment includes: determining the terminal voltage of each node at the current moment based on the node current between two adjacent nodes at the previous moment and the node area of each node; in response to the terminal voltage not satisfying the cut-off condition, determining the current solid-phase resistance, current liquid-phase resistance, and current electrode surface charge transfer resistance of each node in the first direction; obtaining the current equivalent resistance based on the current solid-phase resistance, current liquid-phase resistance, and current electrode surface charge transfer resistance; and determining the current equivalent electric potential based on the terminal voltage of each node, the current equivalent resistance, and the node current at the previous moment.

[0010] In the above embodiments, when performing current simulation on the current collector plane, not only the electrochemical reaction process of the battery in the thickness direction and particle radius direction is considered, but also the differences in the width and height are considered, which can simulate the true geometric structure of the battery cell and reflect the aging phenomenon at different positions.

[0011] In some embodiments, determining the terminal voltage of each node at the current moment based on the node current between two adjacent nodes at the previous moment and the node area of each node includes: determining the plane current density of each node on the current collector plane based on the node current between two adjacent nodes at the previous moment and the node area of each node; the node area is determined based on the distribution of multiple nodes on the current collector plane; determining the solid-phase electric potential of each node on the positive and negative current collectors based on the plane current density and the distance between the positive and negative current collectors of the battery cell in the first direction; and determining the terminal voltage of each node at the current moment based on the solid-phase electric potential of each node on the positive and negative current collectors.

[0012] In some embodiments, the current simulation method further includes: obtaining the geometric structure parameters and regional grid parameters of the battery cell; the geometric structure parameters at least include the battery cell structure parameters and tab structure parameters; partitioning the current collector plane based on the battery cell structure parameters and tab structure parameters to obtain multiple current collector regions; performing grid division on each current collector region based on the regional grid parameters to obtain multiple grids and corresponding grid structure parameters of each current collector region; the regional grid parameters at least include the number of grids in each current collector region; determining the nodes connected by the grids as adjacent nodes, and determining the intersections of the multiple grids in each current collector region as multiple nodes.

[0013] In the above embodiments, by performing grid division on the current collector plane, the current collector resistance and node current density can be associated with the grid geometry, making the model have higher calculation accuracy and stronger physical interpretability.

[0014] In some embodiments, the grid structure parameters include the grid width and grid height of the grids corresponding to each current collector region, and the cell structure parameters include at least the current collector thickness; the current simulation method further includes: determining the current collector resistance between two adjacent nodes based on the current collector thickness, the resistivity of the current collector plane, the grid width and grid height of each current collector region.

[0015] In some embodiments, the current simulation method further includes: constructing virtual nodes for the nodes located at the edge of the current collector plane among the multiple nodes, so that each node has a target number of adjacent nodes; correspondingly, determining the node potential of each node based on the initial equivalent resistance, the initial equivalent potential, the charge and discharge current of the cell, and the current collector resistance between two adjacent nodes among the multiple nodes, including: determining the node potential of each node based on the initial equivalent resistance, the initial equivalent potential, the charge and discharge current of the cell, and the current collector resistance between each node and the corresponding target number of adjacent nodes.

[0016] In the above embodiments, by introducing virtual nodes, it is convenient to calculate data such as the current collector resistance and the coefficient matrix, and improves the readability, scalability and robustness of the program.

[0017] In a second aspect, an embodiment of the present application provides a current simulation device, including: an acquisition module, configured to acquire the current collector resistance between two adjacent nodes among multiple nodes on the current collector plane of the cell, the charge and discharge current of the cell, the initial equivalent resistance and the initial equivalent potential of each node in the first direction; wherein, the multiple nodes are determined based on the geometric structure of the cell, and the first direction is the thickness direction of the current collector; a construction module, configured to construct a potential linear equation for each node based on the initial equivalent resistance, the initial equivalent potential, the charge and discharge current, and the current collector resistance between two adjacent nodes among the multiple nodes through Kirchhoff's current law; a solution module, configured to solve the potential linear equation of each node to obtain the node potential of each node; a determination module, configured to determine the node current between two adjacent nodes on the current collector plane based on the node potential of each node and the current collector resistance between two adjacent nodes, so as to simulate the current distribution among multiple nodes during the charge and discharge process of the cell.

[0018] In a third aspect, an embodiment of the present application provides a current simulation method, including: a memory, configured to store executable instructions; a processor, configured to implement the above current simulation method when executing the executable instructions stored in the memory.

[0019] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, storing executable instructions, which are used to cause a processor to implement the above current simulation method when executing the executable instructions.

[0020] Fifthly, an embodiment of the present application provides a computer program product, which includes executable instructions stored in a computer-readable storage medium; when a processor of the current simulation method reads the executable instructions from the computer-readable storage medium and executes the executable instructions, the above-mentioned current simulation method is implemented.

[0021] The above description is only an overview of the technical solution of the present application. In order to be able to understand the technical means of the present application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of the present application more obvious and understandable, the following specifically illustrates the specific implementation manners of the present application. Description of the Drawings

[0022] Figure 1 is a schematic structural diagram of the current simulation method provided by an embodiment of the present application;

[0023] Figure 2 is an optional process schematic of the current simulation method provided by an embodiment of the present application Figure 1 ;

[0024] Figure 3 is a simplified schematic diagram of the current collector plane nodes provided by an embodiment of the present application;

[0025] Figure 4 is an optional process schematic of the current simulation method provided by an embodiment of the present application Figure 2 ;

[0026] Figure 5 is a schematic diagram of node area calculation provided by an embodiment of the present application;

[0027] Figure 6 is an optional process schematic of the current simulation method provided by an embodiment of the present application Figure 3 ;

[0028] Figure 7 is a schematic diagram of regional grid division provided by an embodiment of the present application;

[0029] Figure 8 is a schematic diagram of the nodes of the current collector plane provided by an embodiment of the present application;

[0030] Figure 9 is a schematic design flow diagram of the current distribution model of the cell current collector provided by an embodiment of the present application;

[0031] Figure 10 is a schematic diagram of the unwound winding cell provided by an embodiment of the present application;

[0032] Figure 11 is a schematic diagram of node connection provided by an embodiment of the present application;

[0033] Figure 12 It is a flow chart of the coupling relationship between the electrochemical model and the current distribution model of the current collector provided by the embodiments of the present application;

[0034] Figure 13 It is a flow chart of the current distribution model of the current collector provided by the embodiments of the present application. Detailed implementation manners

[0035] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings. The described embodiments should not be construed as limiting the present application. All other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present application.

[0036] In the following description, reference is made to "some embodiments", which describe a subset of all possible embodiments. However, it can be understood that "some embodiments" can be the same subset or different subsets of all possible embodiments, and can be combined with each other without conflict. Unless otherwise defined, all technical and scientific terms used in the embodiments of the present application have the same meaning as commonly understood by those skilled in the technical field to which the embodiments of the present application belong. The terms used in the embodiments of the present application are only for the purpose of describing the embodiments of the present application and are not intended to limit the present application.

[0037] Currently, due to its high energy density, long cycle life and low self-discharge characteristics, lithium-ion batteries have become the most widely used battery type in the current new energy vehicle field. Although lithium battery technology is constantly breaking through, since lithium batteries are an extremely complex system, there is still insufficient understanding of the mechanism in aspects such as aging. In order to better explain phenomena such as local lithium deposition at different positions in lithium batteries and to improve this defect through design and process means, it is necessary to conduct in-depth research on lithium batteries through simulation means.

[0038] The most widely used battery model in related technologies for simulation is the pseudo-two-dimensional (P2D) model. The P2D model is a simplified model that describes the internal electrochemical process of the battery. Based on the porous electrode theory and the concentrated solution theory, the complex physical and chemical phenomena inside the battery are simplified into the concentration and potential distributions in the thickness direction of the battery electrode and the radius direction of the solid-phase particles. Through this simplification, the model can more efficiently describe the charge and discharge behavior of the battery while maintaining high accuracy, and is suitable for battery design and performance optimization.

[0039] However, the P2D model only reflects the electrochemical reaction process in the thickness direction and the particle radius direction of the battery, ignoring the differences in the width and height aspects, and cannot determine the current distribution at different positions on the current collector plane.

[0040] To alleviate the problems existing in the related technologies, the applicant constructed a P4D model to simulate the real geometric structure of the battery cell and reflect the aging phenomenon of the current collector plane at different positions. The P4D model is based on the P2D model, taking into account the differences in the width and height of the single cell, simulating the real geometric structure of the cell and reflecting the electrochemical phenomena at different positions. The first problem to be considered in the P4D model is the current distribution at different positions of the cell.

[0041] Based on the above considerations, through in-depth research, the inventor provided a current simulation method, which can obtain the current collector resistance between adjacent two nodes among multiple nodes on the current collector plane of the battery cell, the charge and discharge current of the battery cell, the initial equivalent resistance and the initial equivalent electric potential of each node in the thickness direction of the current collector. By Kirchhoff's current law, based on the initial equivalent resistance, the initial equivalent electric potential, the charge and discharge current and the current collector resistance between adjacent two nodes among multiple nodes, a linear electric potential equation of each node is constructed, and the linear electric potential equation of each node is solved to obtain the node electric potential of each node. Based on the node electric potential of each node and the current collector resistance between adjacent two nodes, the node current between adjacent two nodes on the battery current collector plane is determined to determine the current distribution among multiple nodes during the charge and discharge process of the battery cell.

[0042] In this way, in the embodiment of the present application, by dividing the current collector plane in the width and height directions, multiple nodes are obtained, and adjacent two nodes are connected by the current collector resistance. Through the charge and discharge current of the battery cell and the resistances of adjacent nodes on the current collector in the thickness direction and the plane direction, the electric potential of each node during the charge and discharge process can be determined. Based on the current collector resistance between adjacent nodes, the current between adjacent nodes can be obtained, and further the current distribution on the current collector plane during the charge and discharge process of the battery can be obtained. In this way, the simulation of the current distribution on the current collector plane of the battery during the charge and discharge process can be realized, the area where the current density abnormally increases (such as the edge, near the welding point) can be located, and the local aging risk of the battery cell can be warned in advance; and the design of the battery cell can be optimized based on the current distribution result to obtain the scheme with the most uniform current distribution to improve the battery life.

[0043] New energy batteries are increasingly widely used in life and industry. New energy batteries are not only applied to energy storage power systems such as hydraulic, thermal, wind and solar power stations, but also widely used in electric transportation such as electric bicycles, electric motorcycles, electric vehicles, and many other fields such as aerospace. With the continuous expansion of the application fields of power batteries, the market demand is also continuously increasing. In the embodiments of the present application, the battery involved may be a battery cell, also known as a cell. A battery cell refers to the basic unit that can realize the mutual conversion of chemical energy and electrical energy, and can be used to make a battery module or a battery pack, so as to supply power to the electrical device. The battery cell can be a secondary battery, which refers to a battery cell that can continue to be used after the battery cell discharges by means of charging to activate the active material. The battery cell can be a lithium-ion battery, a sodium-ion battery, a sodium-lithium-ion battery, a lithium metal battery, a sodium metal battery, a lithium-sulfur battery, a magnesium-ion battery, a nickel-metal hydride battery, a nickel-cadmium battery, a lead-acid battery, etc., and the embodiments of the present application do not limit this.

[0044] In the embodiments of the present application, the cell can refer to a cell of any shape such as a square cell or a round cell. And the cell usually refers to a battery cell, that is, one of the basic units that make up the battery. The cell is the core component of the battery and is responsible for storing and releasing electrical energy. The cell can be: a lithium-ion battery cell (Li-ion Cell), a lithium polymer battery cell (Li-polymer Cell), a nickel-metal hydride battery cell (NiMH Cell), etc. The embodiments of the present application do not limit the type of the cell, and can be specifically selected according to the actual application scenario. In the embodiments of the present application, the cell is the core component of the battery pack. A battery pack usually includes multiple cells, and these cells are combined together to provide the required electrical energy capacity and voltage. The components of the battery pack at least include: battery cells, a battery management system (BMS, Battery Management System), a housing, a connection harness, a connector and an interface, etc. These components work together to combine the battery cells into a fully functional battery pack for various application scenarios. For example, the battery pack can be applied to electric vehicles, energy storage systems, portable electrical devices, solar systems, wind energy systems, emergency backup power supplies, power tools or electric bicycles, etc. The embodiments of the present application do not limit this, and can be specifically selected according to the actual application scenario.

[0045] It should be noted that the battery pack can use different types of battery cells, such as lithium-ion batteries, nickel-metal hydride batteries, lithium polymer batteries, etc., which are specifically determined according to the actual application requirements and performance requirements.

[0046] In the embodiments of the present application, the battery may also be a single physical module including one or more battery cells to provide higher voltage and capacity. When there are multiple battery cells, the multiple battery cells are connected in series, parallel or in a hybrid connection through a busbar component.

[0047] The following describes an exemplary application of the current simulation method according to the embodiments of the present application. The current simulation method provided by the embodiments of the present application can be executed by a processor of a computer device. When implemented, the computer device can be any suitable device with data processing capabilities. It can be understood that in the battery industrial production, the computer device can refer to any one of a programmable logic controller (PLC), a single-chip microcomputer, a middle-level computer, and a host computer, or can also be a server, a notebook computer, a tablet computer, a desktop computer, a smart phone, etc. In some embodiments, the computer device may include a memory and a processor. Among them, the memory stores a computer program that can run on the processor, and the processor implements the current simulation method when executing the program.

[0048] Figure 1 is a schematic structural diagram of the current simulation method provided by the embodiments of the present application. Figure 1 The current simulation device 10 shown includes at least one processor 110, a memory 150, at least one network interface 120, and a user interface 130. Each component in the current simulation method is coupled together through a bus system 140. It can be understood that the bus system 140 is used to realize the connection and communication between these components. In addition to including a data bus, the bus system 140 also includes a power bus, a control bus, and a status signal bus. However, for the sake of clear description, in Figure 1 all kinds of buses are labeled as the bus system 140.

[0049] The processor 110 may be an integrated circuit chip with signal processing capabilities, such as a general-purpose processor, a digital signal processor (DSP, Digital Signal Processor), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. Among them, the general-purpose processor may be a microprocessor or any conventional processor, etc.

[0050] The user interface 130 includes one or more output devices 131 capable of presenting media content, and one or more input devices 132.

[0051] The memory 150 can be removable, non-removable, or a combination thereof. Exemplary hardware devices include solid-state memories, hard disk drives, optical disk drives, etc. The memory 150 optionally includes one or more storage devices that are physically remote from the processor 110. The memory 150 includes volatile memory, non-volatile memory, or both volatile and non-volatile memory. The non-volatile memory can be a read-only memory (ROM), and the volatile memory can be a random access memory (RAM). The memory 150 described in the embodiments of the present application is intended to include any suitable type of memory. In some embodiments, the memory 150 is capable of storing data to support various operations. Examples of such data include programs, modules, and data structures, or subsets or supersets thereof, which will be described exemplarily below.

[0052] The operating system 151 includes system programs for processing various basic system services and performing hardware-related tasks, such as the framework layer, the core library layer, the driver layer, etc., for implementing various basic services and processing hardware-based tasks;

[0053] The network communication module 152 is used to reach other computing devices via one or more (wired or wireless) network interfaces 120. Exemplary network interfaces 120 include: Bluetooth, Wi-Fi (Wireless Fidelity), and USB (Universal Serial Bus), etc.;

[0054] The input processing module 153 is used to detect one or more inputs or interactions from one of one or more input devices 132.

[0055] In some embodiments, the device provided by the embodiments of the present application can be implemented in software. Figure 1 Shown is a current simulation device 154 stored in the memory 150. The current simulation device 154 can be the current simulation device in the current simulation method. It can be software in the form of a program, a plug-in, etc., and includes the following software modules: an acquisition module 1541, a construction module 1542, a solution module 1543, and a determination module 1544. These modules are logical, and thus can be combined arbitrarily or further split according to the functions to be implemented. The functions of each module will be described below.

[0056] In some other embodiments, the device provided by the embodiments of the present application can be implemented in a hardware manner. As an example, the device provided by the embodiments of the present application can be a processor in the form of a hardware decoding processor, which is programmed to execute the current simulation method provided by the embodiments of the present application. For example, the processor in the form of a hardware decoding processor can adopt one or more application specific integrated circuits (ASICs), DSPs, programmable logic devices (PLDs), complex programmable logic devices (CPLDs), field programmable gate arrays (FPGAs) or other electronic components.

[0057] The technical solution of the present application will be elaborated in detail below with reference to the accompanying drawings.

[0058] Figure 2 It is an optional process schematic of the current simulation method provided by the embodiments of the present application Figure 1 , as Figure 2 shown, the current simulation method provided by the embodiments of the present application can be implemented through steps S201 to S204:

[0059] Step S201: Obtain the current collector resistance between two adjacent nodes among multiple nodes on the current collector plane of the battery cell, the charge and discharge current of the battery cell, the initial equivalent resistance and the initial equivalent potential of each node in the first direction; wherein, the multiple nodes are determined based on the geometric structure of the battery cell, and the first direction is the thickness direction of the current collector.

[0060] In the embodiments of the present application, in order to simulate the current collector plane of the battery cell, the battery cell can be unfolded and meshed. The battery cell can be composed of a spiral structure (i.e., JR) similar to a cylinder wound by a cathode, an anode and a separator. Each JR is composed of several small units of a positive electrode, a separator and a negative electrode, and each layer has an anode tab and a cathode tab respectively. Take any one layer and cut it along the middle position and unfold it to obtain a plane composed of a large surface, a corner and a tab, that is, the current collector plane.

[0061] Before meshing, the embodiments of the present application can perform zoning processing on the plane. Here, the entire plane can be divided into multiple regions, and the distance between adjacent nodes in each region can be the same or different.

[0062] In the embodiments of the present application, zoning and node division can be performed according to the geometric structure of the battery cell, such as JR width, JR thickness, JR height, tab width, tab height, and tab center distance, to obtain multiple nodes on the current collector plane.

[0063] In some embodiments, the current collector resistance between two adjacent nodes among the multiple nodes on the current collector plane can be calculated based on the resistivity of the current collector, the area of the current collector between the two nodes, and the thickness of the current collector.

[0064] In some embodiments, according to Thevenin's theorem, each battery cell can be regarded as a combination of an equivalent voltage source and an equivalent resistance. After each layer of JR is unfolded, the thickness direction is the positive current collector, the positive electrode, the separator, the negative electrode, and the negative current collector in sequence. Therefore, the initial equivalent resistance and the initial equivalent potential of each node in the first direction can refer to the initial resistance and the initial voltage source of each node in the thickness direction of the current collector (i.e., between the positive current collector and the negative current collector).

[0065] The initial equivalent resistance and the initial equivalent potential refer to the initial resistance and the initial potential at the initial moment (i.e., before the charge and discharge of the battery cell at each node), which can be obtained through the P2D model. For example, the initial equivalent resistance at each node at the initial moment can be the ohmic resistance value on the node area in the P2D model, and the initial equivalent potential can be determined according to the initial positive and negative balance potentials (which is the potential difference between the positive and negative electrodes) in the P2D model at the initial moment.

[0066] In some embodiments, the charge and discharge current refers to the current when charging or discharging the battery cell, which can be a fixed value.

[0067] Step S202: Based on the initial equivalent resistance, the initial equivalent potential, the charge and discharge current, and the current collector resistance between two adjacent nodes among the multiple nodes, construct a linear equation of the potential for each node according to Kirchhoff's current law.

[0068] In the embodiments of the present application, Figure 3 is a simplified schematic diagram of the nodes on the current collector plane provided by the embodiments of the present application. As Figure 3 shown, it can be the aluminum foil (positive electrode) or copper foil (negative electrode) current collector plane of the battery cell. Assume that there are 9 nodes connected to each other through the current collector resistance 301 on the current collector plane, such as nodes 1 to 9. The charge and discharge current flows in from node 9 and out from node 7. According to Kirchhoff's current law, the sum of the input current and the output current of each node is 0. Therefore, based on the initial equivalent resistance, the initial equivalent potential, the charge and discharge current, and the current collector resistance between two adjacent nodes among the multiple nodes, a linear equation of the potential can be listed for each node.

[0069] For example, Figure 3The current collector plane shown is an aluminum foil current collector plane. The adjacent nodes of node 6 on this plane are 3, 5, and 9. The node adjacent to node 6 in the first direction is node 6' on the copper foil current collector. Node 6 and node 6' are equivalent to an equivalent resistance 302 and an equivalent voltage source 303, and the corresponding initial equivalent resistance is R 66' , and the initial equivalent electric potential is Ueq, both of which can be obtained from the P2D model. Assume that the node electric potentials of nodes 3, 5, 6, 9, and 6' are , and a linear equation for node 6 can be constructed as shown in formula (1):

[0070] (1);

[0071] Based on the above method, a linear equation for the electric potential of each node can be obtained.

[0072] Step S203: Solve the linear equations of the electric potentials of each node to obtain the node electric potentials of each node.

[0073] Here, after obtaining the linear equation of each node, a system of linear equations corresponding to multiple nodes is obtained. Only the node electric potential is the unknown. After solving this system of equations, the node electric potentials of each node can be obtained.

[0074] Continue to refer to Figure 3 , according to Kirchhoff's current law, the sum of the input current and the output current of each node is 0. A linear equation can be listed for each node, and combining the linear equations listed for all nodes can construct a system of linear equations as shown in formula (2):

[0075] (2);

[0076] Among them, V1 to V9 are the node electric potentials of each node, R 12 is the current collector resistance between nodes 1 and 2, and U eq1 to U eq9 are the equivalent voltage sources (i.e., equivalent electric potentials) between the positive and negative current collectors of each node. The equivalent electric potentials of different nodes can be different at the same moment.

[0077] When solving the above system of linear equations, the above system of linear equations can be transformed into the form of a matrix equation, as shown in formula (3):

[0078] (3);

[0079] Among them, b is the current vector; V is the node electric potential vector; A is the coefficient matrix.

[0080] In the embodiment of the present application, for the convenience of description, it can be considered that the current collector resistance between the current collector nodes is equal to the equivalent resistance. Actually, it needs to be calculated according to the resistance formula.

[0081] Here, A and b are known, and the coefficient matrix is a square matrix and a diagonal matrix. Therefore, the LU decomposition method or the Gaussian elimination method can be used to solve the node potential vector V to obtain the node potentials of each node.

[0082] Step S204: Based on the node potentials of each node and the current collector resistance between two adjacent nodes, determine the node current between two adjacent nodes on the battery current collector plane to simulate the current distribution among multiple nodes during the charge and discharge process of the battery cell.

[0083] In the embodiment of the present application, after determining the node potentials of the current collector plane, the node current between adjacent nodes can be determined according to the potential difference and the current collector resistance between adjacent nodes. After obtaining the node currents between all adjacent nodes among multiple nodes, the current distribution on the current collector plane of the battery cell can be obtained.

[0084] In some embodiments, the aging area on the current collector plane can be determined according to the current distribution. For example, the larger the current, the higher the current density and the more serious the aging.

[0085] In the embodiment of the present application, by dividing the current collector plane in the width and height directions, multiple nodes are obtained. Two adjacent nodes are connected by the current collector resistance. Through the charge and discharge current of the battery cell and the resistances of adjacent nodes on the current collector in the thickness and plane directions, the potentials of each node during the charge and discharge process can be determined. Based on the current collector resistance between adjacent nodes, the current between adjacent nodes can be obtained, and then the current distribution on the current collector plane during the charge and discharge process of the battery can be obtained. In this way, the simulation of the current distribution on the current collector plane of the battery during the charge and discharge process can be realized, the area with abnormal increase in current density (such as the edge, near the welding point) can be located, and the local aging risk of the battery cell can be warned in advance; and the design of the battery cell can be optimized based on the current distribution result to obtain the most uniform current distribution scheme to improve the battery life.

[0086] In the embodiment of the present application, the charge and discharge of the battery is a continuous process, so the embodiment of the present application can determine the current distribution between each node at each moment during the charge and discharge process. Figure 4 This is an optional process schematic of the current simulation method provided by the embodiment of the present application Figure 2 , as Figure 4 shown, the current simulation method provided by the embodiment of the present application can also be implemented through steps S401 to S405:

[0087] Step S401: Based on the node potentials of each node, determine the cell voltage of the battery cell; the cell voltage is the potential difference between the positive terminal tab and the negative terminal tab on the current collector plane.

[0088] The current simulation method provided by the embodiments of the present application can simulate the current distribution at each moment during the charge and discharge process of a battery cell. Therefore, it is necessary to determine whether the cell voltage reaches the charge and discharge cut-off voltage of the battery. For example, during the simulation of the charging process, when the cell voltage is greater than the cut-off voltage for battery charging (e.g., 4 volts (V)), the simulation ends, and the current distribution on the current collector plane during the charging process is obtained.

[0089] Here, taking a single battery cell as an example, after determining the node potentials of each node, the potentials of the positive and negative current collectors are determined based on the node potentials corresponding to the nodes on the current collectors, and the difference between the positive current collector potential and the negative current collector potential is determined as the cell voltage of the cell.

[0090] In some embodiments, the potential of the current collector can be obtained by averaging the node potentials of multiple nodes in the current collector, or the potential of the current collector can be obtained by averaging the node potentials of the nodes on the upper edge of the current collector. The present application does not limit the method for determining the potential of the current collector.

[0091] Step S402: Compare the cell voltage with the cut-off voltage during the charge and discharge process of the cell to obtain a comparison result.

[0092] In some embodiments, if the charging process of the battery is simulated, the cut-off voltage is the charging cut-off voltage, e.g., 4V; if the discharging process of the battery is simulated, the cut-off voltage is the discharging cut-off voltage, e.g., 3V.

[0093] Comparing the cell voltage with the cut-off voltage is to determine whether the battery has been fully charged or discharged. When the charge and discharge are completed, the simulation of the embodiments of the present application stops. When it is not completed, the simulation of the next moment can be continued to obtain the current distribution at each moment during each charge and discharge process.

[0094] Step S403: In response to the comparison result indicating that the cell voltage does not meet the cut-off condition, based on the node current between two adjacent nodes on the current collector plane at the previous moment, determine the current equivalent resistance and the current equivalent potential of each node in the first direction at the current moment.

[0095] Here, the cell voltage not meeting the cut-off condition means that when the cell voltage does not reach the charging cut-off voltage or the discharging cut-off voltage, the current equivalent resistance and the current equivalent potential of each node in the first direction at the current moment can be determined through the node current between two adjacent nodes on the current collector plane at the previous moment. Here, the current equivalent potential and the current equivalent resistance at the current moment can be determined through the P2D model.

[0096] Step S404: Calculate the cell voltage of the cell at the next moment based on the current equivalent resistance and the current equivalent potential.

[0097] In an embodiment of the present application, after determining the current equivalent resistance and the current equivalent potential, the node potential of each node at the next moment can be determined based on the current equivalent resistance, the current equivalent potential, the charge and discharge current, and the current collector resistance between two adjacent nodes among multiple nodes. Based on this node potential, the cell voltage of the cell at the next moment can be calculated.

[0098] Based on the method in step S203, the node potential of each node at the next moment can be obtained, and then step S401 is repeated to obtain the cell voltage of the cell at the next moment.

[0099] Step S405: In response to the cell voltage satisfying the cut-off condition, the node current between two adjacent nodes at each moment before the cell voltage satisfies the cut-off condition is determined as the current distribution between multiple nodes during the charge and discharge process of the cell.

[0100] In an embodiment of the present application, after obtaining the potential of each node, the node current flowing between adjacent nodes can be calculated according to Ohm's law (for example, if calculating the current between nodes 7 and 8, it is obtained by dividing the potential difference between 7 and 8 by the equivalent resistance between 7 and 8, and thus the current distribution between each node can be calculated), so as to obtain the current distribution between multiple nodes at the current moment during the charge and discharge process of the cell.

[0101] Here, if the cell voltage at the current moment satisfies the cut-off condition, the node current between two adjacent nodes at each moment before the cell voltage satisfies the cut-off condition can be determined as the current distribution between multiple nodes during the charge and discharge process of the cell, so as to obtain the simulation result of the current distribution on the current collector plane at each moment during the charge and discharge process of the cell, which is used to optimize the design of the cell.

[0102] In an embodiment of the present application, by comparing the cell voltage of the cell with the cut-off voltage at each moment, the simulation result of the current distribution on the current collector plane at each moment during the charge and discharge process of the cell can be obtained. Based on this result, the heat generation situation and aging situation at each position of the cell can be predicted, which provides a direct basis for the design of the thermal management system, thereby avoiding local overheating and prolonging the battery life; at the same time, through this simulation result, the cell design can be optimized to balance the current distribution, reduce the excessive consumption of local active substances, and prolong the battery life and performance.

[0103] In some embodiments, in step S403, the current equivalent potential and the current equivalent resistance at the current moment are determined through the P2D model, which can be implemented through steps S4031 to S4034:

[0104] Step S4031: Based on the node current between two adjacent nodes at the previous moment and the node area of each node, the terminal voltage of each node is determined.

[0105] In the embodiments of the present application, the terminal voltage of each node may refer to the potential difference between the positive and negative current collectors of each node, and can be calculated based on the node current between two adjacent nodes at the previous moment and the node area of each node.

[0106] Here, the node current between two adjacent nodes at the previous moment can be obtained through step S204.

[0107] In some embodiments, determining the terminal voltage of each node can be achieved through steps S1 to S4:

[0108] Step S1: Based on the node current between two adjacent nodes at the previous moment and the node area of each node, determine the planar current density of each node in the plane of the current collector; the node area is determined based on the distribution of multiple nodes on the plane of the current collector.

[0109] In some embodiments, Figure 5 is a schematic diagram for calculating the node area provided by the embodiments of the present application. As Figure 5 shown, taking four representative nodes in the figure as an example, the node area of is S1 / 4; the node area of is S1 / 2; the node area of is S1; the node area of is (S1 + S2) / 4. The calculation of the planar current density corresponding to each node can be represented by formula (4):

[0110] (4);

[0111] Wherein, is the sum of the currents in different directions of node (1, 1) on the plane of the current collector, is the planar current density of node (1, 1).

[0112] Step S2: Based on the planar current density and the distance between the positive and negative current collectors of the battery cell in the first direction, determine the solid-phase potential of each node on the positive and negative current collectors.

[0113] In the embodiments of the present application, after determining the planar current density, the solid-phase potential and liquid-phase potential of each node on the positive and negative current collectors can be calculated through an electrochemical model (such as the P2D model), that is, the solid-phase potential and liquid-phase potential of each node on the positive current collector and the negative current collector respectively.

[0114] Here, taking the solid-phase potential of the negative current collector of the node as the starting point, and given the current density, the solid-phase potential of this node at the negative current collector can be calculated , the liquid-phase potential of the node at the negative current collector can be calculated from the liquid-phase lithium-ion concentration, and the equilibrium potential of the node at the negative current collector can be calculated from the solid-phase lithium-ion concentration. Finally, the overpotential of the node at the negative current collector is obtained, and the local current density of the interface reaction is calculated through this overpotential. Finally, the solid-phase current density is updated through this local current density, and the solid-phase potential value of the node at the positive current collector is obtained based on the solid-phase current density. 。

[0115] Step S3: Based on the solid-phase potentials of each node on the positive and negative current collectors, determine the terminal voltage of each node at the current moment.

[0116] In the embodiment of the present application, the terminal voltage of each node at the current moment can be the solid-phase potential difference between the node on the positive and negative current collectors, as shown in formula (5):

[0117] (5);

[0118] where L is the distance between the positive current collector and the negative current collector, that is, the distance between the positive and negative current collectors of the battery cell in the first direction.

[0119] Step S4032: In response to the terminal voltage not satisfying the cut-off condition, determine the current solid-phase resistance, current liquid-phase resistance, and current electrode surface charge transfer resistance of each node in the first direction.

[0120] In the embodiment of the present application, the terminal voltage not satisfying the cut-off condition may mean that the terminal voltage of each node has not reached the charging cut-off voltage or the discharging cut-off voltage either. The current solid-phase resistance of each node in the first direction can be obtained according to the P2D model 、current liquid-phase resistance and current electrode surface charge transfer resistance 。

[0121] Step S4033: Based on the current solid-phase resistance, current liquid-phase resistance, and current electrode surface charge transfer resistance, obtain the current equivalent resistance.

[0122] In some embodiments, the current equivalent resistance is as shown in formula (6):

[0123] (6);

[0124] Step S4034: Based on the terminal voltage of each node, the current equivalent resistance, and the node current at the previous moment, determine the current equivalent potential.

[0125] In some embodiments, the current equivalent potential is as shown in formula (7):

[0126] (7);

[0127] Wherein, I is the node current at the previous moment of the current moment.

[0128] When the current simulation of the current collector plane is carried out in the embodiments of the present application, not only the electrochemical reaction process of the battery in the thickness direction and the particle radius direction is considered, but also the differences in the width and height are considered, and the aging phenomenon of the current collector at different positions can be reflected.

[0129] In some embodiments, in order to implement the simulation of the current collector plane, taking the square shell wound battery cell as an example for illustration, which is also applicable to other forms of battery cells including but not limited to laminated ones. The winding structure in the square shell battery cell is called the battery jelly roll (JR). Each JR is composed of several small units of positive electrode, separator, and negative electrode, and each layer has an anode tab and a cathode tab respectively. In the embodiments of the present application, any layer can be taken and cut and unfolded along the middle position to obtain a plane composed of a large surface, a corner, and a tab, that is, the current collector plane. It should be noted that in the embodiments of the present application, any layer of the JR can be unfolded to simulate the electrochemical performance of different layers.

[0130] Figure 6 is an optional process schematic diagram of the current simulation method provided by the embodiments of the present application Figure 3 , as Figure 6 shown, the current simulation method provided by the embodiments of the present application can also be implemented through steps S601 to S604:

[0131] Step S601, obtain the geometric structure parameters and regional grid parameters of the battery cell; the geometric structure parameters at least include the battery cell structure parameters and the tab structure parameters.

[0132] In some embodiments, the battery cell structure parameters may include the JR width, JR thickness, and JR height, and the tab structure parameters may include the tab width, tab height, and tab center distance. The regional grid parameters may include the number of partitions of the current collector plane and the number of grids in the width and height directions of each region, that is, how many grids are divided in each region.

[0133] Step S602, based on the battery cell structure parameters and the tab structure parameters, partition the current collector plane to obtain a plurality of current collector regions.

[0134] Figure 7 is a schematic diagram of regional grid division provided by the embodiments of the present application, as Figure 7As shown, JR is cut along the dotted line to obtain the current collector plane, which is divided into seven regions, A1 to A7. It should be noted that additional regions can be added on this basis. For example, corner regions can be added longitudinally to regions A1 and A5, or a thinned region can be added laterally below the tab (corner regions and thinned regions have a greater impact on battery life). However, the following description uses the division of seven regions as an example.

[0135] like Figure 7 As shown, based on the cell structure parameters and the tab structure parameters, the current collector plane is partitioned to obtain 7 current collector areas.

[0136] Step S603 : Based on the regional grid parameters, each current collector region is gridded to obtain multiple grids and corresponding grid structure parameters of each current collector region; the regional grid parameters at least include the number of grids in each current collector region.

[0137] Continue to refer to Figure 7 For region A1, the regional grid parameters can be to divide the current collector region into 24 grids, the area of each grid can be the same or different, and each current collector region is grid-divided in turn to obtain multiple grids and corresponding grid structure parameters of each current collector region.

[0138] Here, the grid structure parameters may include the grid width and grid height of the grid corresponding to each current collector region. The number of grids in each region may be the same or different.

[0139] Step S604: determine the nodes connected by the grids as adjacent nodes, and determine the intersections of multiple grids in each current collector region as multiple nodes.

[0140] In the embodiment of the present application, nodes connected by a grid may be determined as adjacent nodes, for example Figure 7 Nodes 702, 703 and 704 in FIG are adjacent nodes of node 701, and intersections of multiple grids in each current collector region are determined as multiple nodes.

[0141] In the embodiment of the present application, by meshing the current collector plane, the current collector resistance and node current density can be associated with the grid geometry, so that the model has higher computational accuracy and stronger physical interpretability.

[0142] In some embodiments, the grid structure parameters include the grid width and grid height of the grid corresponding to each current collector area, and the battery cell structure parameters include at least the current collector thickness. The current simulation method may further include step S11:

[0143] Step S11: Determine the current collector resistance between two adjacent nodes based on the current collector thickness, the resistivity of the current collector plane, the grid width, and the grid height of each current collector region.

[0144] In some embodiments, taking the resistance in the width direction of the positive current collector as an example, the calculation of the current collector resistance is shown in Equation (8):

[0145] (8);

[0146] Where, is the conductivity, which is related to the material and is a fixed value; is the resistivity of the aluminum foil (positive current collector), is the thickness of the aluminum foil (i.e., the thickness of the aluminum foil current collector), is calculated from the grid width, is calculated from the grid height; A is a coefficient matrix constructed from the current collector resistance.

[0147] Where, continuing to refer to Figure 3 , if calculating the current collector resistance between nodes 7 and 8, L w is the width between 7 and 8, and L h is half of the width of 4 - 7; if calculating the current collector resistance between nodes 4 and 5, L w is the width between 4 and 5, and L h is half of the width of 4 - 7 plus half of the width of 1 - 4.

[0148] In some embodiments, since there may be multiple situations for the number and position of adjacent nodes of a node at the current collector boundary, dealing with them case - by - case will lead to a redundant structure and difficulty in standardization. Therefore, in the embodiments of the present application, the concept of virtual nodes is introduced. Taking a single - layer coating as an example, the maximum number of adjacent nodes of a node on the current collector is 5. Virtual nodes are introduced at nodes where the number of adjacent nodes is not equal to 5, so as to ensure the uniformity of the number of adjacent nodes of the current collector nodes.

[0149] Therefore, the current simulation method may further include Step S21:

[0150] Step S21: Construct virtual nodes for the nodes located at the edge of the current collector plane among multiple nodes, so that each node has a target number of adjacent nodes.

[0151] In the embodiments of the present application, based on the aforementioned grid division method, the target number may be 5. Here, for different grid division methods, the target number may be different.

[0152] Figure 8 is a schematic diagram of the nodes on the current collector plane provided by the embodiments of the present application, as shown in Figure 8As shown in the figure, there are various situations regarding the number and positions of the adjacent nodes of a node. For example, the number of adjacent nodes of node 1 at the origin of coordinates is 3, namely the right node, the upper node, and the opposite node; while the number of adjacent nodes of node 2 with coordinates (0, 1) is 4, namely the right node, the upper node, the lower node, and the opposite node; the number of adjacent nodes of node 801 is 5, namely the left node, the right node, the upper node, the lower node, and the opposite node. When writing a program, if different cases are discussed to construct the coefficient matrix A, the program will be very long and difficult to standardize.

[0153] Therefore, the embodiment of this application introduces the concept of virtual nodes, unifying the number of adjacent nodes of each node to 5. For example, a virtual node is introduced above node 802 to make its number of adjacent nodes 5, and the positions of the adjacent nodes are respectively the upper node, the lower node, the left node, the right node, and the opposite node. After such processing, all nodes of the grid have a unified structure. During actual calculation, only simple processing needs to be performed on the virtual nodes of each node, and then based on the node coordinates, the resistance value between adjacent nodes of the current collector can be calculated, thereby constructing the coefficient matrix A. This method of constructing the coefficient matrix is called the five-node method.

[0154] Correspondingly, step 201 can be implemented through step S2011:

[0155] Step S2011: Determine the node potential of each node based on the initial equivalent resistance, the initial equivalent potential, the charge and discharge current of the battery cell, and the current collector resistance between each node and the corresponding target number of adjacent nodes.

[0156] As shown in formula (2), after determining the adjacent resistance of each node, the node potential of each node can be determined based on the initial equivalent resistance, the initial equivalent potential, the charge and discharge current of the battery cell, and the current collector resistance between each node and the corresponding target number of adjacent nodes.

[0157] The embodiment of this application facilitates the calculation of data such as the current collector resistance and the coefficient matrix by introducing virtual nodes, improving the readability, scalability, and robustness of the program.

[0158] Next, an exemplary application of the embodiment of this application in an actual application scenario will be described.

[0159] An embodiment of the present application provides a current distribution model for a battery cell current collector. The model divides the current collector into several grids in width and height. At each grid node, there are planar adjacent nodes and vertically adjacent nodes. Planar adjacent nodes are connected by the current collector resistance, and vertically adjacent nodes are connected by the equivalent resistance and equivalent voltage calculated by the P2D model. At each grid node, a linear equation system can be constructed using Kirchhoff's current law, and the matrix equation can be solved using the matrix decomposition (LU, Lower-Upper Decomposition) method to obtain the potential of each node of the current collector, thereby obtaining the current distribution of the battery cell at different positions. Through this model, the current magnitude distributed at each node of the lithium battery can be quickly calculated, realizing the simulation design of the current collector tab. In this way, when the actual geometric structure of the battery cell, such as geometric dimensions and tab position, is known, based on the equivalent potential and equivalent resistance of the P2D model at the current moment, the current magnitude distributed at each node at the next moment can be quickly calculated through the current collector current distribution model, which serves as the input of the P2D model at each node. By using this current collector current distribution model, the current distribution of the battery cell can be effectively optimized and a high-performance current collector tab design can be achieved.

[0160] Since the number and position of adjacent nodes of the nodes at the boundary of the current collector may vary, if the situation is handled separately, the structure will be complicated and difficult to standardize. Therefore, this application introduces the concept of virtual nodes. Taking single-layer coating as an example, the maximum number of adjacent nodes of the nodes on the current collector is set to 5. Virtual nodes are introduced at nodes where the number of adjacent nodes is not equal to 5, thereby ensuring the uniformity of the number of adjacent nodes of the current collector nodes. At the same time, a coordinate system is introduced to facilitate the positioning and numbering of each node. In this way, by introducing virtual nodes and a coordinate system, the calculation of data such as the current collector resistance and coefficient matrix is facilitated, while improving the readability, scalability and robustness of the program.

[0161] In the embodiment of the present application, after JR is meshed, the width and height of each mesh can be calculated based on the width and height of the large surface and the tab, and the lateral and longitudinal spacing between the nodes can be obtained. When the conductivity and thickness of the collector are known, the lateral resistance and longitudinal resistance between the collector nodes can be obtained using the resistance calculation formula. Since the physical quantity of current density is usually required in the P2D model, after obtaining the current allocated to each node in the current distribution model, the node current needs to be converted into node current density through the node area. The node area can be calculated based on the lateral and longitudinal spacing between the nodes. In this way, by associating the collector resistance and node current density with the grid geometry, the model has higher calculation accuracy and stronger physical interpretability.

[0162] Figure 9 This is a schematic diagram of the design process of the current distribution model of the battery core collector provided in the embodiment of the present application.Figure 9 As shown, the process includes steps S901 to S903:

[0163] Step S901: unfolding the wound battery cell into a single layer and dividing the cell into a grid.

[0164] This application takes the geometric structure of a single-layer unfolded wound battery cell (i.e., battery cell) as the research object. The geometric structure includes two parts: the plane where the large surface is located and the pole ear. It can be divided into regions and grids according to the geometric grid parameters input by the user and preprocessed (for example, the width and height of each region and the width and height of each region grid are calculated). The preprocessed results are used for subsequent models.

[0165] Step S902: constructing a cell electrochemical model and a current collector current distribution model.

[0166] Here, the electrochemical model and the current collector current distribution model are bidirectionally coupled. The electrochemical model can calculate the equivalent resistance and equivalent potential at each node of the grid as the input of the current collector current distribution model, and the current collector current distribution model will calculate the current density at each node of the grid as the input of the electrochemical model, and the current at the grid node at each moment is obtained in sequence.

[0167] Step S903: Design a current distribution model for the current collector.

[0168] The embodiments of this application introduce the technical details of the program design of the collector current distribution model from the aspects of grid division, virtual node construction, and resistivity matrix construction.

[0169] Step S901 is Figure 10 The square shell wound battery cell is used as an example for description. The method provided in this application is also applicable to other forms of battery cells including but not limited to laminated cells.

[0170] Figure 10 Schematic diagram of the unfolding of the wound battery cell provided in the embodiment of the present application. Figure 10 As shown, there are two winding structures 1001 in the square shell battery cell. This winding structure is called JR. Each JR is composed of several layers of small units such as positive electrode, separator, and negative electrode, and each layer has an anode tab 1002 and a cathode tab 1003. Take any layer of the JR and cut and unfold it along the middle position to obtain a plan view consisting of a large surface 1004, a corner 1005 and tabs (anode tab 1002 and cathode tab 1003).

[0171] It should be noted that in the embodiments of the present application, any layer of the JR can be unfolded to simulate the electrochemical performance of different layers. However, this method can also unfold the entire JR to perform the simulation design of the current collector tab. After each layer is unfolded, the thickness direction is successively the positive electrode current collector 1006, the positive electrode 1007, the separator 1008, the negative electrode 1009, and the negative electrode current collector 1010, which reflects the situation of single-layer coating. However, this method is also applicable to the case of double-layer coating.

[0172] Before mesh generation, the unfolded plane needs to be partitioned. Please refer to Figure 7 , where the entire plane is divided into 7 regions from A1 to A7. It should be noted that regions can be added on this basis. For example, corner regions can be longitudinally added in the A1 region and the A5 region, or thinning regions can be horizontally added under the tabs (corner regions and thinning regions are regions that have a greater impact on the battery life). However, in the following description, the case of dividing into 7 regions is taken as an example for illustration.

[0173] In the embodiments of the present application, standardized input parameters are introduced. One type is geometric parameters, and the other type is mesh parameters. The geometric parameters mainly include the JR width, JR thickness, JR height, tab width, tab height, and tab center distance. The mesh parameters mainly include the number of meshes in the width and height directions of each region from A1 to A7. Given these parameters, the width and height of each region and the region meshes can be obtained.

[0174] Node numbers and node coordinates are also introduced. The purpose of node numbers is to facilitate positioning when processing nodes, and the purpose of node coordinates is to facilitate the calculation process of the current collector resistance. The setting of node numbers has strong flexibility. It can start numbering from the tab regions A6 and A7, or start numbering from the current collector regions A1 to A5. In each region, it can be numbered sequentially from left to right or from right to left, or sequentially from bottom to top or from top to bottom. Here, it is numbered sequentially from bottom to top in the regions from A1 to A7, and then the node with node number 1 is used as the coordinate origin to establish the coordinate axes. The width direction is the x-axis direction, and the height direction is the y-axis direction, so that the specific coordinate values of each node can be determined for subsequent model use.

[0175] Figure 11 is the schematic diagram of node connection provided by the embodiments of the present application. As Figure 11 shown, the nodes 1102 in the current collector plane 1101 are connected to each other by resistors 1103. The aluminum foil current collector node 1104 (i.e., the positive electrode current collector node) and the copper foil current collector node 1105 (i.e., the negative electrode current collector node) are connected by the equivalent resistance and equivalent voltage source calculated by the P2D model. Therefore, for any node on a current collector plane, there are at most 5 nodes connected to it.

[0176] In an embodiment of the present application, the equivalent resistance at each node at the initial moment can be set to the ohmic resistance value of the node area in the P2D model, and the equivalent potential at the initial moment is determined based on the positive and negative electrode equilibrium potential at the initial moment in the P2D model.

[0177] Figure 12 This is a flow chart of the coupling relationship between the electrochemical model and the current collector current distribution model provided in the embodiment of the present application, such as Figure 12 As shown, bidirectional coupling of the electrochemical model and the current collector current distribution model can be achieved through steps S1201 to S1206:

[0178] Step 1201: Calculate the equivalent resistance and equivalent potential of the node at the initial moment.

[0179] The equivalent resistance at each node at the initial moment can be set to the ohmic resistance value of the node area in the P2D model, and the equivalent potential at the initial moment is determined according to the positive and negative electrode equilibrium potentials in the P2D model at the initial moment.

[0180] Step 1202: Calculate node current and potential based on the current collector current distribution model.

[0181] Here, the current of the battery cell flows into the aluminum foil tab and flows out of the copper foil tab. The equivalent resistance and equivalent potential at the initial moment are input into the current collector current distribution model, and the input current density of the P2D model at each node at the next moment and the potential distribution on the current collector can be obtained. If the potential of the aluminum foil tab of the current collector (which can be the average value of the top few nodes of the tab) reaches the cut-off voltage (if it is a charging process, the charging voltage can be from 2.5v to 3.65v, at this time 3.65v is the cut-off voltage; if it is a discharge process, the cut-off voltage is the lowest voltage), the calculation ends; if the cut-off voltage is not reached, the concentration equation and potential equation of the P2D model are solved at each node to obtain the terminal voltage of each node. If the solution meets the cut-off condition (that is, the terminal voltage of a node meets the cut-off voltage), the calculation ends, otherwise the equivalent resistance and equivalent potential are updated and input into the current collector current distribution model for the next iterative calculation.

[0182] Step 1203: Determine whether the potential meets the cut-off condition.

[0183] In the embodiment of the present application, the node potential can be calculated using an electrochemical model (i.e., a P2D model). When the node potential meets the cutoff condition, the calculation ends; otherwise, step S1204 is executed.

[0184] The potential here can be obtained from the node terminal voltage, current and equivalent resistance at the initial moment.

[0185] Step 1204: Calculate the terminal voltage of each node.

[0186] The P2D model of the battery takes into account the physical phenomena and chemical reactions inside the battery, involving many physical and chemical principles at the microscopic level. Therefore, the description of the battery is more accurate, and more physical quantities reflecting the internal electrochemical changes of the battery can be obtained, such as the solid-liquid phase concentration and potential. The P2D model consists of partial differential equations and algebraic equations. In order to improve the calculation speed during use, the equations are simplified, but only the most original equation form is introduced here, and the specific simplification methods and solution means are not discussed.

[0187] The solid-phase diffusion equation describes the diffusion process of lithium ions in the solid-phase active particles by using Fick's second law, reflecting the change of the solid-phase lithium-ion concentration with time and position. The solid-phase diffusion equation is shown in Equation (9):

[0188] (9);

[0189] where is the solid-phase diffusion coefficient, is the solid-phase lithium-ion concentration, t is time, and r is the position of the radius of the solid-phase active particle.

[0190] The liquid-phase diffusion equation means that the mass transfer process of lithium ions in the electrolyte satisfies the Nernst-Planck equation. Ignoring the effect of convection and considering the influence of diffusion and electromigration, the liquid-phase diffusion equation is shown in Equation (10):

[0191] (10);

[0192] where is the porosity, is the liquid-phase lithium-ion concentration, x is the position in the thickness direction, is the effective diffusion coefficient, is the lithium-ion transference number, j is the interfacial reaction volume current density, is the liquid-phase current.

[0193] The solid-phase potential is the potential on the electronic conductor. The change of the solid-phase potential of the battery is described by Ohm's law, as shown in Equation (11):

[0194] (11);

[0195] where is the solid-phase potential, is the solid-phase current, is the effective conductivity.

[0196] The liquid-phase potential is the potential on the ionic conductor and can also be derived from the Nernst-Planck equation. The liquid-phase potential consists of two parts: the potential difference caused by the ionic current and the potential difference caused by the concentration difference, as shown in Equation (12):

[0197] (12);

[0198] Wherein, is the liquid-phase potential, is the effective ionic conductivity, f is the activity coefficient, R is the gas constant, and T is the temperature.

[0199] The insertion-extraction reaction on the particle surface conforms to the Butler-Volmer equation, which is derived from the transition state theory and describes the electrochemical reaction at the solid-liquid interface. The interfacial electrochemical reaction equation is as shown in Equation (13):

[0200] (13);

[0201] Wherein, is the local current density of the interfacial reaction, is the transfer coefficient, is the overpotential = , is the equilibrium potential, which can be obtained according to the solid-phase lithium-ion concentration; is the exchange current density, reflects the ability of an electrode reaction to gain and lose electrons and the ease of the electrode reaction, as shown in Equation (14):

[0202] (14);

[0203] Wherein, k is the reaction rate constant, is the maximum solid-phase lithium-ion concentration, is the solid-phase surface lithium-ion concentration.

[0204] Based on the above equations, the battery terminal voltage , that is, the calculation formula for the potential difference between the positive and negative current collectors of the node is as shown in Equation (15):

[0205] (15);

[0206] Wherein, L is the distance between the positive current collector and the negative current collector.

[0207] Here, taking the solid phase potential of the negative electrode current collector as the starting point, when the current density is known, the solid phase potential of the adjacent grid in the thickness direction of the current collector (that is, the node at the negative electrode current collector) can be calculated according to formula (11). The liquid phase potential of the adjacent grid can be calculated by the liquid phase lithium ion concentration (such as formulas 10 and 12), and the equilibrium potential can be calculated by the solid phase lithium ion concentration. Finally, the overpotential of the adjacent grid is obtained, and then the local current density is reflected through the overpotential calculation interface (formulas 13 and 14). Finally, the solid phase current density is updated by this local current density, and the solid phase potential of the next adjacent node is calculated. This process is repeated, and finally the solid phase potential value at the positive electrode current collector can be calculated, thereby calculating the terminal voltage.

[0208] Step 1205: Determine whether the terminal voltage meets the cut-off condition.

[0209] In some embodiments, after determining the node terminal voltage, it is determined whether the terminal voltage meets the cutoff condition, that is, compared with the cutoff voltage. If the cutoff condition is met, the process ends; otherwise, step S1206 is executed.

[0210] Step 1206: Update the equivalent resistance and equivalent potential of the node at the current moment.

[0211] Equivalent resistance Solid phase resistance , liquid phase resistance and electrode surface charge transfer resistance These resistors can be calculated based on the variable parameters in the P2D model, as shown in formula (16):

[0212] (16);

[0213] Equivalent potential The terminal voltage , current I (value calculated at the previous moment) and equivalent resistance The calculation is as shown in formula (17):

[0214] (17);

[0215] Please refer to Figure 3, There are 9 nodes on the plane that are interconnected through the current collector resistance 301, such as nodes 1 to 9. The current flows in from node 9 and out from node 7. According to Kirchhoff's current law, the sum of the input current and the output current at each node is 0. Here, the principle of calculating the potential of each node is introduced. To simplify the calculation difficulty, only the nodes on the current collector plane are used in the formula for calculation, and the resistance and potential between the positive and negative current collectors are not considered. In this way, a linear equation can be listed for each node, and combining all the linear equations listed for the nodes can construct a linear equation system as shown in formula (18):

[0216] (18);

[0217] where, V1 to V9 are the potentials of each node, and R 12 is the current collector resistance between nodes 1 and 2.

[0218] Taking the resistance in the width direction of the aluminum foil as an example, the calculation of the current collector resistance is as shown in formula (19):

[0219] (19);

[0220] where, is the conductivity, which is related to the material and is a fixed value; is the resistivity of the aluminum foil, is the thickness of the aluminum foil (i.e., the thickness of the aluminum foil current collector), is calculated from the grid width, is calculated from the grid height; A is the coefficient matrix constructed by the current collector resistance.

[0221] When solving the above linear equation system, the above linear equation system can be transformed into the form of a matrix equation, as shown in formula (20):

[0222] (20);

[0223] where, b is the current vector.

[0224] In the embodiments of the present application, for the convenience of description, it can be considered that the resistances between the current collector nodes are all equal. In fact, it needs to be calculated according to the resistance formula. In the case of considering the resistances to be equal, A can be expressed as in formula (21):

[0225] (21);

[0226] B and V can be as shown in formula (22):

[0227] (22);

[0228] Here, A and b are known, and the coefficient matrix is a square matrix and a diagonal matrix. Therefore, the LU decomposition method or the Gaussian elimination method can be used to solve for V.

[0229] After obtaining the electric potential of each node, the current flowing between nodes can be calculated according to Ohm's law (for example, if calculating the current between nodes 7 and 8, it is obtained by dividing the potential difference between 7 and 8 by the equivalent resistance between 7 and 8. Thus, the current distribution between each node can be calculated to complete the calculation of the current distribution model of the current collector.

[0230] The above is only to show the calculation principle of the current distribution model of the current collector. In the actual planar expansion diagram of the wound battery cell, the structure will be more complex due to the presence of the tabs. Please refer to Figure 8 , there are various situations for the number and positions of the adjacent nodes of a node. For example, the number of adjacent nodes of node 1 at the coordinate origin is 3, namely the right node, the upper node, and the opposite node; while the number of adjacent nodes of node 2 with coordinates (0, 1) is 4, namely the right node, the upper node, the lower node, and the opposite node; the number of adjacent nodes of node 801 is 5, namely the left node, the right node, the upper node, the lower node, and the opposite node. If different cases are discussed to construct the coefficient matrix A when writing the program, the program will be very long and difficult to standardize.

[0231] Therefore, the embodiment of the present application innovatively introduces the concept of virtual nodes, unifying the number of adjacent nodes of each node to 5. For example, a virtual node is introduced above node 802 to make the number of its adjacent nodes 5, and the positions of the adjacent nodes are the upper node, the lower node, the left node, the right node, and the opposite node respectively. After such processing, all nodes of the grid have a unified structure. During actual calculation, only simple processing needs to be performed on the virtual nodes of each node, and then the resistance between adjacent nodes of the current collector can be calculated according to the node coordinates, thereby constructing the coefficient matrix A. This method of constructing the coefficient matrix is called the five-node method.

[0232] In some embodiments, the input in the electrochemical model is the current density of each node, and what is calculated by the current distribution model of the current collector is the current value allocated to each node. Therefore, it is necessary to convert the current into the current density through the node area corresponding to each node.

[0233] Please refer to Figure 5 , taking four representative nodes in the figure as an example, the node area of is S1 / 4; the node area of is S1 / 2; the node area of is S1; the node area of is (S1 + S2) / 4. The calculation of the current density corresponding to each node can be expressed by formula (23):

[0234] (23);

[0235] Figure 13 is a flowchart of the current distribution model of the current collector provided by the embodiment of the present application. As Figure 13 shown, the determination of the current distribution between nodes can be achieved through steps S131 to S139:

[0236] Step S131, obtain the three-dimensional geometric parameters and the number of meshes of the current collector plane.

[0237] Here, the user can input the three-dimensional geometric parameters and the number of meshes of the battery cell. The user can input the geometric dimensions of the battery cell JR and the number of meshes divided in each region in the data file, and the program will read the parameters in the data file for subsequent model calculations.

[0238] Step S132, perform regional data preprocessing and construct regional arrays.

[0239] Preprocess the data input by the user, including calculating the width and height of each region and the width and height of the meshes in each region. Based on the input and preprocessed data, regional arrays can be constructed, including arrays formed by the starting row and column numbers and coordinates of each region, arrays formed by the number and length of horizontal and vertical meshes in each region, and arrays formed by the horizontal and vertical boundary coordinates of each region.

[0240] Step S133, determine whether the current region Ai is greater than A7.

[0241] After data preprocessing, start constructing the coefficient matrix using the five-node method, starting from region A1 and constructing until region A7 is completed. When the region number is between A1 and A7, execute the loop steps of S134 to S137. When the region number exceeds A7, execute the end steps of S138 to S139.

[0242] Step S134, determine the coordinates of each node within the region.

[0243] The node numbers within the region can be recorded in sequence from bottom to top and from left to right. The coordinates of each node within the region can be calculated based on the starting row and column coordinate array of the region and the horizontal and vertical mesh length array of the region.

[0244] Step S135, establish virtual nodes.

[0245] The introduction of virtual nodes in this application facilitates the unification of the data structure of each node. However, since virtual nodes do not actually exist, certain processing of the coordinates of virtual nodes is required. Specifically, when processing, it is first necessary to determine whether a node is a virtual node through the horizontal and vertical boundary coordinate arrays of the region. If the node coordinates exceed the boundary values, the coordinate values of this virtual node need to be set to the coordinate values of its connected nodes (in this way, the distance between the virtual node and the connected node is 0, and the calculation of the current collector resistance between the two nodes is also 0).

[0246] Step S136: Calculate the current collector resistance.

[0247] Substitute the current collector resistivity, current collector thickness, and node coordinates into the current collector resistance calculation formula to obtain the resistance value between adjacent nodes of the current collector.

[0248] Step S137: Construct the coefficient matrix.

[0249] Based on the serial numbers of the nodes and adjacent nodes, the position of the reciprocal of the resistance on the coefficient matrix can be determined, and based on the current collector resistance, equivalent resistance, and equivalent potential, the specific value of the reciprocal of the resistance can be determined. When the entire region is traversed, a complete coefficient matrix can be constructed.

[0250] Step S138: Solve the matrix equation using LU decomposition.

[0251] After calculating the complete coefficient matrix, the matrix equation can be solved to obtain the potential value of each node. Since the coefficient matrix is a standard diagonal square matrix, the LU decomposition method can be used to decompose the coefficient matrix into an upper triangular matrix and a lower triangular matrix, thereby converting the matrix equation into two triangular equations for solution.

[0252] Step S139: Output the current distribution.

[0253] Through the solution of the matrix equation, the potential value of each node can be obtained. Therefore, it is necessary to calculate the current value based on the equivalent resistance and equivalent potential between the node and the opposite node, and convert this current value into current density through the node area, which can be used as the input current density of the P2D model. Then, the simulation calculation of the current distribution model of the cell current collector is terminated.

[0254] When the actual geometric structure of the cell, such as geometric dimensions, tab position, etc., is known in the embodiments of this application, based on the equivalent potential and equivalent resistance of the P2D model at the current moment, the current magnitude allocated to each node at the next moment can be quickly calculated through this current distribution model of the current collector, so as to be used as the input of the P2D model at each node. Using this current distribution model of the current collector, the simulation design of the current collector tab can be realized.

[0255] In the embodiments of the present application, by introducing virtual nodes and a coordinate system, it is convenient to calculate data such as the current collector resistance and the coefficient matrix, and at the same time, the readability, scalability, and robustness of the program are improved.

[0256] In the embodiments of the present application, by associating the current collector resistance and the node current density with the grid geometry, the model has higher calculation accuracy and stronger physical interpretability.

[0257] Based on Figure 1 Given the current simulation device 154, the current simulation device 154 may include an acquisition module 1541, a construction module 1542, a solution module 1543, and a determination module 1544. Among them, the acquisition module 1541 is used to acquire the current collector resistance between two adjacent nodes among multiple nodes on the current collector plane of the battery cell, the charge and discharge current of the battery cell, the initial equivalent resistance and the initial equivalent electric potential of each node in the first direction; wherein, the multiple nodes are determined based on the geometric structure of the battery cell, and the first direction is the thickness direction of the current collector; the construction module 1542 is used to construct a linear equation of the electric potential of each node based on the Kirchhoff's current law, the initial equivalent resistance, the initial equivalent electric potential, the charge and discharge current, and the current collector resistance between two adjacent nodes among the multiple nodes; the solution module 1543 is used to solve the linear equation of the electric potential of each node to obtain the node electric potential of each node; the determination module 1544 is used to determine the node current between two adjacent nodes on the current collector plane based on the node electric potential of each node and the current collector resistance between two adjacent nodes, so as to simulate the current distribution among multiple nodes during the charge and discharge process of the battery cell.

[0258] In some embodiments, the current simulation device further includes: a third determination module, configured to determine the battery cell voltage of the battery cell based on the node electric potential of each node; the battery cell voltage is the potential difference between the positive electrode tab and the negative electrode tab on the current collector plane; a comparison module, configured to compare the battery cell voltage with the cut-off voltage during the charge and discharge process of the battery cell to obtain a comparison result; a second determination module, configured to, in response to the comparison result indicating that the battery cell voltage does not meet the cut-off condition, determine the current equivalent resistance and the current equivalent electric potential of each node in the first direction at the current moment based on the node current between two adjacent nodes on the current collector plane at the previous moment; a calculation module, configured to calculate the battery cell voltage of the battery cell at the next moment based on the current equivalent resistance and the current equivalent electric potential; a fifth determination module, configured to, in response to the battery cell voltage meeting the cut-off condition, determine the node current between two adjacent nodes at each moment before the battery cell voltage meets the cut-off condition as the current distribution among multiple nodes during the charge and discharge process of the battery cell.

[0259] In some embodiments, the second determination module is further configured to determine the terminal voltage of each node at the current moment based on the node current between two adjacent nodes at the previous moment and the node area of each node; in response to the terminal voltage not satisfying the cut-off condition, determine the current solid-phase resistance, the current liquid-phase resistance, and the current electrode surface charge transfer resistance of each node in the first direction; obtain the current equivalent resistance based on the current solid-phase resistance, the current liquid-phase resistance, and the current electrode surface charge transfer resistance; and determine the current equivalent electric potential based on the terminal voltage of each node, the current equivalent resistance, and the node current at the previous moment of the current moment.

[0260] In some embodiments, the second determination module is further configured to determine the planar current density of each node in the current collector plane based on the node current between two adjacent nodes at the previous moment and the node area of each node; the node area is determined based on the distribution of multiple nodes in the current collector plane; determine the solid-phase electric potential of each node on the positive and negative current collectors based on the planar current density and the distance between the positive and negative current collectors of the battery cell in the first direction; and determine the terminal voltage of each node at the current moment based on the solid-phase electric potential of each node on the positive and negative current collectors.

[0261] In some embodiments, the current simulation device further includes: a first acquisition module, configured to acquire the geometric structure parameters and regional grid parameters of the battery cell; the geometric structure parameters at least include the battery cell structure parameters and the tab structure parameters; a partitioning module, configured to partition the current collector plane based on the battery cell structure parameters and the tab structure parameters to obtain a plurality of current collector regions; a grid division module, configured to perform grid division on each current collector region based on the regional grid parameters to obtain a plurality of grids and corresponding grid structure parameters of each current collector region; the regional grid parameters at least include the number of grids in each current collector region; and a third determination module, configured to determine the nodes connected by the grids as adjacent nodes, and determine the intersections of the plurality of grids in each current collector region as a plurality of nodes.

[0262] In some embodiments, the grid structure parameters include the grid width and grid height of the grids corresponding to each current collector region, and the battery cell structure parameters at least include the current collector thickness; the current simulation device further includes: a fourth determination module, configured to determine the current collector resistance between two adjacent nodes based on the current collector thickness, the resistivity of the current collector plane, the grid width, and the grid height of each current collector region.

[0263] In some embodiments, the current simulation device further includes: a construction module, configured to construct virtual nodes for the nodes located at the edge of the current collector plane among the plurality of nodes, so that each node has a target number of adjacent nodes; correspondingly, the first determination module is further configured to determine the node electric potential of each node based on the initial equivalent resistance, the initial equivalent electric potential, the charge and discharge current of the battery cell, and the current collector resistance between each node and the corresponding target number of adjacent nodes.

[0264] It should be noted that the description of the device in the embodiments of the present application is similar to the description of the above method embodiments and has similar beneficial effects as the method embodiments. Therefore, it will not be elaborated here. For the technical details not disclosed in the embodiments of this device, please refer to the description of the method embodiments of the present application for understanding.

[0265] The embodiments of the present application provide a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, some or all of the steps in the above method are implemented. The computer-readable storage medium can be transient or non-transient.

[0266] The embodiments of the present application provide a computer program, including computer-readable code. When the computer-readable code runs in a computer device, the processor in the computer device executes to implement some or all of the steps in the above method.

[0267] The embodiments of the present application provide a computer program product. The computer program product includes a non-transient computer-readable storage medium storing a computer program. When the computer program is read and executed by a computer, some or all of the steps in the above method are implemented. The computer program product can be specifically implemented in a manner of hardware, software, or a combination thereof. In some embodiments, the computer program product is specifically embodied as a computer storage medium. In other embodiments, the computer program product is specifically embodied as a software product, such as a Software Development Kit (SDK), etc.

[0268] It should be understood that the "one embodiment" or "an embodiment" mentioned throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of the present application. Therefore, the "in one embodiment" or "in an embodiment" that appears throughout the specification does not necessarily refer to the same embodiment. In addition, these specific features, structures, or characteristics can be combined in one or more embodiments in any suitable manner. It should be understood that in various embodiments of the present application, the size of the serial numbers of the above steps / processes does not mean the order of execution. The order of execution of each step / process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application. The serial numbers of the embodiments of the present application above are only for description and do not represent the advantages or disadvantages of the embodiments.

[0269] The present application uses descriptions of orientation or positional relationships indicated by "upper", "lower", "top", "bottom", "front", "rear", "inner", and "outer", etc. This is only for the convenience of describing the present application and does not indicate or imply that the device referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the protection scope of the present application.

[0270] In the description of the present application, it should also be noted that, unless otherwise clearly specified and defined, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0271] It should be noted that in the present application, the term "comprising", "including" or any other variant thereof is intended to cover a non-exclusive inclusion, such that a process, method, article or device comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the phrase "comprising a..." does not exclude the presence of additional identical elements in the process, method, article or device comprising that element.

[0272] In several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. The device embodiments described above are merely illustrative. For example, the division of units is only a logical function division, and there may be other division methods in actual implementation. For example, multiple units or components can be combined, or integrated into another system, or some features can be ignored, or not executed. In addition, the couplings, direct couplings or communication connections between the various components shown or discussed may be through some interfaces, and the indirect couplings or communication connections of devices or units may be electrical, mechanical or other forms.

[0273] The units described above as separate components may or may not be physically separated, and the components shown as units may or may not be physical units; they can be located in one place or distributed to multiple network units; some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment. In addition, the various functional units in the embodiments of the present application can all be integrated into one processing unit, or each unit can be separately used as a unit, or two or more units can be integrated into one unit; the above integrated units can be implemented in the form of hardware, or in the form of hardware plus software functional units.

[0274] The above are only the embodiments of the present application and are not intended to limit the protection scope of the present application. Any modifications, equivalent replacements, and improvements made within the spirit and scope of the present application are all included in the protection scope of the present application.

Claims

1. A current simulation method, characterized in that, The current simulation method includes: Obtaining the current collector resistance between adjacent two nodes among multiple nodes on the current collector plane of the battery cell, the charge and discharge current of the battery cell, the initial equivalent resistance and initial equivalent potential of each node in the first direction; wherein, the multiple nodes are determined based on the geometric structure of the battery cell, and the first direction is the thickness direction of the current collector; Based on the Kirchhoff's current law, constructing a linear equation of the potential of each node based on the initial equivalent resistance, the initial equivalent potential, the charge and discharge current, and the current collector resistance between adjacent two nodes among the multiple nodes; Solving the linear equation of the potential of each node to obtain the node potential of each node; Based on the node potential of each node and the current collector resistance between adjacent two nodes, determining the node current between adjacent two nodes on the current collector plane to simulate the current distribution among multiple nodes of the battery cell during charge and discharge.

2. The current simulation method according to claim 1, characterized in that, The current simulation method further includes: Determining the battery cell voltage of the battery cell based on the node potential of each node; the battery cell voltage is the potential difference between the positive electrode tab and the negative electrode tab on the current collector plane; Comparing the battery cell voltage with the cut-off voltage of the battery cell during charge and discharge to obtain a comparison result; In response to the comparison result indicating that the battery cell voltage does not meet the cut-off condition, determining the current equivalent resistance and current equivalent potential of each node in the first direction at the current moment based on the node current between adjacent two nodes on the current collector plane at the previous moment; Calculating the battery cell voltage of the battery cell at the next moment based on the current equivalent resistance and the current equivalent potential; In response to the battery cell voltage meeting the cut-off condition, determining the node current between adjacent two nodes at each moment before the battery cell voltage meets the cut-off condition as the current distribution among multiple nodes of the battery cell during charge and discharge.

3. The current simulation method according to claim 2, characterized in that, The determining the current equivalent resistance and current equivalent potential of each node in the first direction at the current moment based on the node current between adjacent two nodes on the current collector plane at the previous moment includes: Determining the terminal voltage of each node at the current moment based on the node current between adjacent two nodes at the previous moment and the node area of each node; In response to the terminal voltage not meeting the cut-off condition, determining the current solid-phase resistance, current liquid-phase resistance and current electrode surface charge transfer resistance of each node in the first direction; Obtaining the current equivalent resistance based on the current solid-phase resistance, the current liquid-phase resistance and the current electrode surface charge transfer resistance; Determining the current equivalent potential based on the terminal voltage of each node, the current equivalent resistance, and the node current at the previous moment.

4. The current simulation method according to claim 3, characterized in that The determining the terminal voltage of each node at the current moment based on the node current between adjacent two nodes at the previous moment and the node area of each node includes: Determining the planar current density of each node on the current collector plane based on the node current between adjacent two nodes at the previous moment and the node area of each node; the node area is determined based on the distribution of the multiple nodes on the current collector plane; Determine the solid-phase potential of each node on the positive and negative current collectors based on the planar current density and the distance between the positive and negative current collectors of the battery cell in the first direction; Determine the terminal voltage of each node at the current moment based on the solid-phase potential of each node on the positive and negative current collectors.

5. The current simulation method according to any one of claims 1 to 4, characterized in that The current simulation method further includes: Obtain the geometric structure parameters and regional grid parameters of the battery cell; the geometric structure parameters at least include the battery cell structure parameters and the tab structure parameters; Partition the current collector plane based on the battery cell structure parameters and the tab structure parameters to obtain a plurality of current collector regions; Perform grid division on each current collector region based on the regional grid parameters to obtain a plurality of grids of each current collector region and the corresponding grid structure parameters; the regional grid parameters at least include the number of grids of each current collector region; Determine the nodes connected by the grids as adjacent nodes, and determine the intersections of the plurality of grids of each current collector region as the plurality of nodes.

6. The current simulation method according to claim 5, wherein The grid structure parameters include the grid width and grid height of the grids corresponding to each current collector region, and the battery cell structure parameters at least include the current collector thickness; The current simulation method further includes: Determine the current collector resistance between two adjacent nodes based on the current collector thickness, the resistivity of the current collector plane, the grid width and grid height of each current collector region.

7. The current simulation method according to claim 5, wherein The current simulation method further includes: Construct virtual nodes for the nodes located at the edge of the current collector plane among the plurality of nodes so that each node has a target number of adjacent nodes; Correspondingly, the step of determining the node potential of each node based on the initial equivalent resistance, the initial equivalent potential, the charge and discharge current of the battery cell, and the current collector resistance between two adjacent nodes among the plurality of nodes includes: Determine the node potential of each node based on the initial equivalent resistance, the initial equivalent potential, the charge and discharge current of the battery cell, and the current collector resistance between each node and the corresponding target number of adjacent nodes.

8. A current simulation device, characterized in that, The current simulation device includes: An acquisition module, configured to acquire the current collector resistance between two adjacent nodes among a plurality of nodes on the current collector plane of the battery cell, the charge and discharge current of the battery cell, the initial equivalent resistance and the initial equivalent potential of each node in the first direction; wherein, the plurality of nodes are determined based on the geometric structure of the battery cell, and the first direction is the thickness direction of the current collector; A construction module, configured to construct a potential linear equation of each node based on the initial equivalent resistance, the initial equivalent potential, the charge and discharge current, and the current collector resistance between two adjacent nodes among the plurality of nodes through Kirchhoff's current law; A solution module, configured to solve the potential linear equation of each node to obtain the node potential of each node; A determination module, configured to determine the node current between two adjacent nodes on the current collector plane based on the node potential of each node and the current collector resistance between two adjacent nodes, so as to simulate the current distribution among a plurality of nodes during the charge and discharge process of the battery cell.

9. An apparatus for simulating the current of a battery, characterized in that, The current simulation device includes: A memory for storing executable instructions; a processor for implementing the current simulation method according to any one of claims 1 to 7 when executing the executable instructions stored in the memory.

10. A computer-readable storage medium, characterized in that, Stored with executable instructions for causing a processor to implement the current simulation method according to any one of claims 1 to 7 when executing the executable instructions.

11. A computer program product, characterized in that, The computer program product includes executable instructions stored in a computer-readable storage medium; When a processor of a current simulation device reads the executable instructions from the computer-readable storage medium and executes the executable instructions, the current simulation method according to any one of claims 1 to 7 is implemented.

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