A battery fast charging simulation method, system, device and medium

Abstract

The application relates to the technical field of batteries, in particular to a battery fast-charging simulation method, system, device and medium, the method comprising the following steps: acquiring a finite element model and simulation parameters of a battery; performing battery fast-charging simulation simulation according to the finite element model and the simulation parameters, and executing the following steps: acquiring a charging rate and a battery internal resistance by table lookup according to a battery state of charge and a battery temperature at the start of a current time step, and updating the battery state of charge and the battery temperature according to a step length of a time step, the charging rate and the battery internal resistance; repeating the simulation simulation steps until a simulation stop condition in the simulation parameters is reached. The application simulates the battery charging process by establishing a finite element model of the battery, and only needs to consider the influence of temperature change and the battery charging rate on the battery during the simulation. Compared with the prior art, the application reduces the difficulty of battery simulation process and performance analysis, and has good engineering practicability and universality.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and specifically to a simulation method, system, device, and medium for fast battery charging. Background Technology

[0002] As the power source of new energy vehicles, the power battery is one of the three core components of electric vehicles. Fast charging simulation of power batteries is an indispensable part of their research and development, and simulation analysis runs throughout the entire product development cycle. Simulation allows for numerical simulation of the fast charging process of power batteries, clarifying not only the real-time changes in important parameters such as charging power, battery temperature, and state of charge (SOC), but also shortening the development cycle and reducing costs. Furthermore, simulation can determine the charging time. Charging time is a crucial indicator for evaluating power battery performance, directly impacting the user experience and market competitiveness of electric vehicles. The existing patent "202111119758.3 A Simulation Method and System for Low-Temperature Charging Performance of Lithium-ion Batteries" simulates battery charging based on an electrochemical-thermal coupled transient model. Therefore, it requires establishing an internal electrochemical reaction model of the battery, considering internal chemical reactions and charge transport processes, and mastering the chemical parameters and reaction mechanisms within the battery pack. This method is challenging, requiring extensive knowledge of electrochemical theory, resulting in limited practicality and versatility. Summary of the Invention

[0003] The present invention provides a simulation method, system, device and medium for fast battery charging. It uses a heat transfer model combined with the influence of temperature changes on the charging rate during the battery charging process to simulate charging, thereby solving the problems of high technical difficulty and application challenges in existing battery simulation technologies.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A simulation method for fast battery charging includes:

[0006] Obtain the finite element model and simulation parameters of the battery;

[0007] Based on the finite element model and the simulation parameters, a fast charging simulation of the battery is performed.

[0008] Based on the battery state of charge and battery temperature at the start of the current time step, the charging rate and battery internal resistance are obtained by looking up a table.

[0009] The battery state of charge and battery temperature are updated based on the time step size, the charging rate, and the battery internal resistance.

[0010] Repeat the above simulation steps until the simulation cutoff condition in the simulation parameters is reached.

[0011] The simulation cutoff condition is when the battery state of charge reaches a preset threshold or the cumulative charging time reaches a preset time.

[0012] Furthermore, the finite element model is obtained through the following steps:

[0013] Obtain a three-dimensional model of the battery;

[0014] The three-dimensional model is then subjected to simplification, surface mesh generation, domain division, and volume mesh generation in sequence.

[0015] A physical connection body is established, and the physical connection body is associated with each domain of the three-dimensional model of the battery after volume meshing to obtain the finite element model of the battery.

[0016] Furthermore, the simulation parameters include the battery's boundary conditions, material properties, total battery capacity, simulation time step, and simulation cutoff condition.

[0017] Furthermore, the step of obtaining the charging rate and battery internal resistance by looking up a table based on the battery state of charge and battery temperature at the start of the current time step includes:

[0018] Based on the battery state of charge and battery temperature at the start of the current time step, the charging rate and battery internal resistance are determined by looking up a first characteristic table and a second characteristic table. The first characteristic table contains the relationship between the charging rate and the battery state of charge and the battery temperature, and the second characteristic table contains the relationship between the battery internal resistance and the battery temperature and the battery state of charge.

[0019] Furthermore, the step of determining the charging rate and the battery internal resistance by looking up the first characteristic table and the second characteristic table based on the battery state of charge and the battery temperature at the start of the current time step includes:

[0020] Get the highest, lowest, and average temperatures of the previous time step;

[0021] Based on the battery state of charge at the start of the current time step, the first characteristic table, the highest temperature, and the lowest temperature, determine the highest temperature charging rate and the lowest temperature charging rate.

[0022] The smaller of the highest temperature charging rate and the lowest temperature charging rate is selected as the charging rate.

[0023] The battery internal resistance is determined based on the second characteristic table, the average temperature, and the battery state of charge.

[0024] Furthermore, the step of updating the battery state of charge and battery temperature based on the time step size, the charging rate, and the battery internal resistance includes:

[0025] The charging current at the start of the current time step of the battery is determined based on the total battery capacity and the charging rate.

[0026] The battery state of charge is updated based on the charging current and the step size of the time step;

[0027] The battery temperature is updated based on the charging current, the battery internal resistance, and the highest temperature.

[0028] Furthermore, the step of determining the charging current at the start of the current time step of the battery based on the total battery capacity and the charging rate includes:

[0029] Based on the battery state of charge at the start of the current time step, the open-circuit voltage is determined by looking up a third characteristic table, which contains the relationship between the battery's open-circuit voltage and the battery state of charge.

[0030] The charging voltage of the battery is obtained based on the charging current at the end of the previous time step, the battery internal resistance, and the open-circuit voltage.

[0031] The power limiting current is determined based on the charging power limit and the charging voltage;

[0032] Based on the total battery capacity and the charging rate, determine the first charging current of the battery at the current time step;

[0033] The smaller of the power limiting current and the first charging current is selected as the charging current at the start of the current time step.

[0034] Furthermore, the step of updating the battery temperature based on the charging current, the battery internal resistance, and the highest temperature includes:

[0035] The heat generation of the battery is calculated based on the charging current and the battery internal resistance.

[0036] Determine the coolant inlet flow rate based on the highest temperature;

[0037] The battery temperature is updated based on the battery heat generation and the coolant inlet flow rate.

[0038] A battery fast charging simulation system includes:

[0039] The acquisition module is used to acquire the finite element model and simulation parameters of the battery;

[0040] The simulation module is used to perform fast charging simulation of the battery based on the finite element model and the simulation parameters. It executes the following steps: based on the battery state of charge and battery temperature at the beginning of the current time step, it obtains the charging rate and battery internal resistance by looking up a table; and it updates the battery state of charge and battery temperature based on the time step size, the charging rate, and the battery internal resistance. The above simulation steps are repeated until the simulation cutoff condition in the simulation parameters is reached. The simulation cutoff condition is that the battery state of charge reaches a preset threshold or the cumulative charging time reaches a preset time.

[0041] An electronic device, the electronic device comprising:

[0042] One or more processors;

[0043] A storage device for storing one or more programs that, when executed by one or more processors, cause the electronic device to implement any of the battery fast charging simulation methods.

[0044] A computer-readable storage medium having a computer program stored thereon, which, when executed by a computer's processor, causes the computer to perform any of the battery fast charging simulation methods described above.

[0045] This invention simulates the battery charging process by establishing a finite element model of the battery. The finite element model is a transient heat transfer simulation model; the simulation does not require knowledge of the internal chemical reaction mechanism of the battery pack, nor does it require inputting chemical parameters. Only the temperature changes during charging and their impact on the battery charging rate need to be considered. Compared to existing technologies for simulating the battery charging process, this invention significantly reduces the difficulty of battery simulation and performance analysis, exhibiting good engineering practicality and versatility. Attached Figure Description

[0046] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. In the drawings:

[0047] Figure 1 This is a schematic diagram illustrating an application scenario of a battery fast charging simulation method provided by an embodiment of the present invention;

[0048] Figure 2 This is a detailed flowchart of a battery fast charging simulation method provided by an embodiment of the present invention;

[0049] Figure 3This is a schematic diagram comparing the simulated and measured current curves provided in the embodiments of the present invention;

[0050] Figure 4 This is a functional block diagram of a battery fast charging simulation method provided by an embodiment of the present invention;

[0051] Figure 5 This is a structural block diagram of the electronic device provided in an embodiment of the present invention. Detailed Implementation

[0052] The embodiments of the present invention will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention and not for limiting the scope of protection of the present invention.

[0053] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0054] In the following description, numerous details are explored to provide a more thorough explanation of embodiments of the invention. However, it will be apparent to those skilled in the art that embodiments of the invention may be practiced without these specific details. In other embodiments, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring embodiments of the invention.

[0055] Please see Figure 1 As shown, Figure 1 This is a schematic diagram illustrating an application scenario of the battery fast-charging simulation method provided by this invention. As the power source for new energy vehicles, simulating the fast-charging process of power batteries is an essential part of the research and development process. By simulating the fast-charging process of power batteries, the real-time changes of important parameters such as charging power, battery temperature, and state of charge (SOC) can be clearly understood. Based on the changes in these parameters, the charging performance of the power battery can be accurately grasped. This invention establishes a heat transfer model for the battery, considering the impact of internal heat generation and dissipation processes on battery charging for fast-charging simulation. It eliminates the need to input complex electrochemical parameters or understand the internal chemical reaction mechanisms of the battery, greatly reducing the analytical difficulty of the simulation and improving its practicality and versatility.

[0056] Figure 2 The following is a flowchart illustrating a simulation method for fast battery charging provided by an embodiment of the present invention, which may include the following steps:

[0057] Step S21: Obtain the finite element model and simulation parameters of the battery.

[0058] In one specific embodiment, the finite element model is obtained by the following steps: obtaining a three-dimensional model of the battery; performing simplification, surface meshing, domain division, and volume meshing on the three-dimensional model in sequence; establishing a physical connection body, and associating the physical connection body with each domain of the three-dimensional model of the battery after volume meshing, so as to obtain the finite element model of the battery.

[0059] Specifically, the process begins by acquiring a 3D model of the battery and simplifying it in 3D design software. This simplifies minor features that do not affect the simulation, primarily reducing the angles or fillets at corners and connections of battery components and equipment. Next, the battery pack modules, water-cooling plates, and casing are grouped and imported into the finite element model preprocessing program for surface mesh generation. The mesh generation graphics and dimensions can be automated by the software, ensuring the battery pack's geometric features are not distorted. Finally, the mesh generation results are checked to avoid T-shaped edges and free edges that could affect the simulation. The meshed model is then divided into domains according to the above groupings. A surface mesh repair tool is used to check the quality of the surface meshes, repairing any that do not meet the requirements until all surface meshes meet the requirements. Next, selective surface mesh reconstruction is performed, creating a mesh continuum of polyhedral and prism layer meshes. The mesh size is set according to requirements, and a boundary layer is generated for the fluid region. Volume mesh generation is then performed. Finally, the quality of the generated mesh is checked. If it does not meet the requirements, the mesh is regenerated; otherwise, the next step is performed. A physical connection body is established, and then associated with each domain of the model after volume mesh generation, finally yielding the finite element model of the battery. The simplified model can be exported as an STP file, which is the format (extension) of 3D graphics files used by computer-aided design and drafting software, containing data of the 3D objects. The model after surface mesh generation can be exported as a BDF (Bitmap Distribution Format) file, a highly readable text-based bitmap font file.

[0060] In one specific embodiment, the simulation parameters include the battery's boundary conditions, material properties, total battery capacity, simulation time step, and simulation cutoff condition.

[0061] Specifically, simulating fast charging of a battery requires not only obtaining the finite element model of the battery but also defining its simulation parameters. These parameters include the battery's boundary conditions, material properties, total battery capacity, simulation time step, and cutoff conditions. The battery's boundary conditions represent the connection relationships between its various components and are categorized as loads and constraints. Material properties can refer to the electrolyte's material properties; different electrolyte materials will have different thermal properties. During the simulation, the charging current needs to be determined based on the total battery capacity and charging rate; the battery's state of charge (SOC) needs to be determined based on the time step and charging current. Before the simulation, simulation cutoff conditions can be pre-set according to requirements. These cutoff conditions can be based on the battery's SOC reaching a certain threshold or specifying the simulated charging time. The time step can be set according to different charging durations. In the preferred scheme, when the charging duration is short, the time step is also set to short, and the time step increases as the charging duration increases. For example, if the charging duration is less than 4 seconds (s), the time step is set to 0.5s; if the charging duration is greater than or equal to 4s and less than 10s, the time step is set to 1s; if the charging duration is greater than or equal to 10s and less than 20s, the time step is set to 2s; if the charging duration is greater than or equal to 20s, the time step is set to 5s; and the number of iterations of the time step is set according to the charging time and the time step size.

[0062] Step S22: Perform battery fast charging simulation based on the finite element model and the simulation parameters. Execute the following steps: based on the battery state of charge and battery temperature at the start of the current time step, obtain the charging rate and battery internal resistance by looking up a table; and update the battery state of charge and battery temperature based on the time step size, the charging rate, and the battery internal resistance.

[0063] Specifically, when simulating the fast charging process of a battery based on its finite element model and simulation parameters, the following steps are taken: First, the corresponding charging rate and battery internal resistance are determined by looking up a table based on the battery's initial temperature and initial state of charge (SOC). Then, the charging current is determined based on the found charging rate and total battery capacity. Combining the initial temperature, charging current, and battery internal resistance, the temperature change during charging can be obtained. The SOC at the end of the current time step is determined based on the simulation time step and charging current. Based on the changed battery temperature and SOC, the corresponding charging rate and battery internal resistance can be determined again by looking up a table. These steps constitute the main process of fast charging simulation using the battery's finite element model. The simulation utilizes a preset thermal management strategy, which considers the impact of heat generation during charging on battery temperature, thereby affecting the charging rate.

[0064] In one specific embodiment, the step of obtaining the charging rate and battery internal resistance by looking up tables based on the battery state of charge and battery temperature at the start of the current time step includes: determining the charging rate and battery internal resistance by looking up a first characteristic table and a second characteristic table based on the battery state of charge and battery temperature at the start of the current time step, wherein the first characteristic table contains the relationship between the charging rate and the battery state of charge and the battery temperature, and the second characteristic table contains the relationship between the battery internal resistance and the battery temperature and the battery state of charge.

[0065] Specifically, before simulating the battery, this invention pre-inputs a first characteristic table, a second characteristic table, and a third characteristic table. The first characteristic table contains the relationship between the charging rate and the battery's state of charge (SOC) and battery temperature. The lookup logic is that the charging rate is linearly interpolated with temperature and then stepped with voltage. The second characteristic table contains the relationship between the battery's internal resistance and battery temperature and SOC. The lookup logic is that the battery's internal resistance is linearly interpolated with temperature and then linearly interpolated with voltage. The third characteristic table determines the open-circuit voltage based on the battery's SOC, and the open-circuit voltage and SOC also have a linear interpolation relationship. Based on the known battery SOC and battery temperature, interpolation functions can be used in the first characteristic table to obtain the corresponding charging rate, battery internal resistance, and open-circuit voltage. As shown in Table 1 (first characteristic table), Table 2 (second characteristic table), and Table 3 (third characteristic table), the specific data corresponding to the SOC and battery temperature are pre-acquired and filled in according to the actual conditions of different battery cells.

[0066] Table 1

[0067] Temp 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.85 0.92 0.95 0.97 -20.1 -20 -15 -10 -5 0 5 10 15 20 25 30 35 40 45 50 55 55.1

[0068] Table 2

[0069]

[0070]

[0071] Table 3

[0072] SOC OCV 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 0.97

[0073] In one specific embodiment, the step of determining the charging rate and the battery internal resistance by looking up a first characteristic table and a second characteristic table based on the battery state of charge and the battery temperature at the start of the current time step includes: obtaining the highest temperature, lowest temperature, and average temperature of the previous time step; determining the highest temperature charging rate and the lowest temperature charging rate based on the battery state of charge at the start of the current time step, the first characteristic table, the highest temperature, and the lowest temperature; selecting the smaller of the highest temperature charging rate and the lowest temperature charging rate as the charging rate; and determining the battery internal resistance based on the second characteristic table, the average temperature, and the battery state of charge.

[0074] Specifically, this invention establishes and defines field functions corresponding to different parameters in the finite element model, and can obtain the parameters required for simulation in real time through the field functions. For example, by establishing field functions for maximum, minimum, and average values, the maximum, minimum, and average values ​​of the battery temperature at each time step can be monitored. When determining the battery charging rate and battery internal resistance based on the battery temperature and battery state of charge, it is necessary to first obtain the highest, lowest, and average temperatures of the battery at the previous time step through the field functions. Based on the highest and lowest temperatures and the battery state of charge at the beginning of the current time step, the corresponding highest temperature charging rate and lowest temperature charging rate are determined respectively through interpolation functions in the first characteristic table; the charging rates at the two temperature states are compared, and the smaller value is selected as the charging rate of the battery at the current time step; then, based on the average temperature and battery state of charge, the corresponding battery internal resistance is determined through interpolation functions in the second characteristic table. If it is the starting time step of the simulation, the charging rate and battery internal resistance corresponding to the starting time step are directly determined through interpolation functions in the first and second characteristic tables based on the initial temperature and initial state of charge of the battery.

[0075] In one specific embodiment, the step of updating the battery state of charge and battery temperature based on the time step size, the charging rate, and the battery internal resistance includes: determining the charging current at the start of the current time step based on the total battery capacity and the charging rate; updating the battery state of charge based on the charging current and the time step size; and updating the battery temperature based on the charging current, the battery internal resistance, and the highest temperature.

[0076] Specifically, in the finite element model, field functions for the battery's actual charging current (Current), state of charge (SOC), and battery temperature (Temp) are established and defined. Based on the product of the determined charging rate and the total battery capacity, the charging current (Current) can be obtained. After defining the product of the charging current and the time step (IT), the state of charge is further defined as the initial state of charge plus the integral of IT divided by the total battery capacity, i.e., SOC = initial SOC + ∫IT / total battery capacity. In this invention, the battery temperature is affected by the heat generated during battery charging and the cooling effect of the coolant flow rate at the battery water-cooling plate inlet. Therefore, field functions for the battery heat generation (Q) and coolant inlet flow rate (Vinlet) also need to be established. Based on the charging current, battery internal resistance, and the battery temperature at the start of the current time step, the battery heat generation (Q) and coolant inlet flow rate (Vinlet) are determined, and the battery temperature can then be updated.

[0077] In one specific embodiment, the step of determining the charging current at the start of the current time step based on the total battery capacity and the charging rate includes: determining the open-circuit voltage by looking up a third characteristic table based on the battery state of charge at the start of the current time step, the third characteristic table containing the relationship between the battery's open-circuit voltage and the battery state of charge; obtaining the battery's charging voltage based on the charging current at the end of the previous time step, the battery's internal resistance, and the open-circuit voltage; determining the power limiting current based on the charging power limit and the charging voltage; determining the first charging current for the current time step based on the total battery capacity and the charging rate; and selecting the smaller of the power limiting current and the first charging current as the charging current at the start of the current time step.

[0078] Specifically, the third characteristic table, which includes the battery's state of charge and open-circuit voltage, input during the establishment of the finite element model, can be interpolated in the third characteristic table using an interpolation function based on the battery's state of charge during simulation to determine the corresponding open-circuit voltage. Furthermore, this invention also establishes and defines field functions for the battery's open-circuit voltage OCV, charging voltage Voltage, and battery internal resistance R, where charging voltage Voltage = open-circuit voltage OCV + charging current Current * battery internal resistance R. This invention can also simulate the battery under power-limited charging conditions such as charging piles through the field function functionality. A field function for the battery's power-limiting current Current_Power is established. Before simulation, the battery's charging power limit is input, and the power-limiting current Current_Power is defined based on the charging power limit and charging voltage Voltage. The charging current determined by the product of the charging rate and the battery's total capacity is used as the first charging current. The values ​​of the first charging current and the power-limiting current are compared, and the smaller one is selected as the battery's charging current.

[0079] In one specific embodiment, the step of updating the battery temperature based on the charging current, the battery internal resistance, and the highest temperature includes: calculating the battery heat generation based on the charging current and the battery internal resistance; determining the coolant inlet flow rate based on the highest temperature; and updating the battery temperature based on the battery heat generation and the coolant inlet flow rate.

[0080] Specifically, the battery temperature Temp in the simulation process of this invention is mainly determined by the battery heat generation Q during fast charging and the coolant inlet velocity Vinlet. The battery heat generation Q and coolant inlet velocity Vinlet are loaded into the finite element model, and then the battery temperature can be obtained in real time through the field function. The battery heat generation Q is defined as the square of the charging current Current multiplied by the battery internal resistance R, with units of watts (W). The coolant inlet velocity Vinlet is defined based on the highest temperature; for example, when the highest temperature is greater than or equal to 25°C, the coolant inlet velocity is 1.38 m / s; when the highest temperature is less than or equal to 20°C, the coolant inlet velocity is 0.001 m / s; and when the highest temperature is greater than 20°C but less than 25°C, the coolant inlet velocity remains unchanged. The instantaneous heat generation of the battery during real-time temperature acquisition can be obtained by multiplying the square of the instantaneous current by the instantaneous internal resistance.

[0081] Step S23: Repeat the above simulation steps until the simulation cutoff condition in the simulation parameters is reached; wherein, the simulation cutoff condition is that the battery state of charge reaches a preset threshold or the cumulative charging time reaches a preset time.

[0082] Specifically, after inputting the simulation cutoff condition before the simulation, the above steps are executed to simulate battery charging. These steps are cyclical steps involving the interaction of battery temperature, charging current, and battery internal resistance. This invention determines the charging rate and battery internal resistance at the simulation start time step based on the initial temperature and initial state of charge applied to the finite element model, and further determines the charging current. Then, the heat generated by the battery under fast charging conditions at this charging current and battery internal resistance is applied to the finite element model in real time, affecting the battery temperature and updating the state of charge. At the next time step of the simulation, the corresponding charging rate and battery internal resistance are determined again based on the updated battery temperature and state of charge, and the charging current is further determined. These steps are repeated until the simulation cutoff condition is met. The cutoff condition can be that the battery state of charge reaches a preset threshold, for example, the simulation ends when the state of charge reaches 80%-100%; or it can be that the specified charging time for the battery simulation is reached, for example, the simulation ends when the charging time reaches 3600s. The battery state of charge or charging time can be monitored by a field function. This invention can also set the convective heat transfer coefficient and ambient temperature for all surfaces in the finite element model that come into contact with the environment, thus considering the influencing factors of battery temperature more comprehensively. To facilitate the analysis of battery fast-charging performance, this invention can also create simulation reports in the finite element model before simulation, such as maximum temperature, minimum temperature, average temperature, state of charge, or charging current, etc. All simulation reports can be defined and obtained through field functions, and plots can be generated after the simulation is completed for easy viewing or data analysis.

[0083] The following are examples of the main parameter definitions used in this embodiment:

[0084] The battery consists of 168 cells with a cell capacity of 150Ah, a charging power limit of 120kW, and an initial SOC of 0.03.

[0085] Define the time step as: ($Time<4)? 0.5:(($Time<10)? 1:(($Time<20)? 2:5));

[0086] Develop a report on the simulated charging current;

[0087] Establish and define the following field functions: current-time step product IT, state of charge SOC, open circuit voltage OCV, cell voltage Voltage, current corresponding to the highest temperature Current_Tmax_jier, current corresponding to the lowest temperature Current_Tmin_jier, actual charging current Current, power limit current Current_Power120kW, cell internal resistance R, battery heat generation Q, and coolant inlet velocity Vinlet;

[0088] IT is defined as: ${Current} * ${TimeStep};

[0089] SOC is defined as: 0.03 + ${Sum of IT} / 3600 / 150;

[0090] OCV is defined as being determined by interpolation of SOC in the third characteristic table: interpolateTable(@Table("OCV"),"SOC",LINEAR,"OCV",${SOC});

[0091] Voltage is defined as: ${OCV} + ${Current} * ${R};

[0092] Current_Tmax_jier is defined as follows: Based on the highest temperature and SOC, the highest temperature charging rate is determined by interpolation in the first characteristic table, and the highest temperature charging rate is then multiplied by the total capacity to obtain Current_Tmax_jier.

[0093] Current_Tmin_jier is defined as follows: Based on the lowest temperature and SOC, the lowest temperature charging rate is determined by interpolation in the first characteristic table, and the lowest temperature charging rate is then multiplied by the total capacity to obtain Current_Tmin_jier;

[0094] Current is defined as: 150*min(${Current_Tmax_jier},${Current_Tmin_jier});

[0095] If the maximum charging power is limited to 120kW, then the power limit current Current_Power120kW is: 120000 / (168*${Voltage'Report});

[0096] At this time, the Current is defined as:

[0097] min(${Current_Power120kW},(150*min(${Current_Tmax_jier},${Current_Tmin_jier})));

[0098] R is defined as: determined by interpolation in the second characteristic table based on the average temperature and SOC;

[0099] Q is defined as: 168 * ${Current} * ${Current} * ${R};

[0100] Vinlet is defined as:

[0101] ${TmaxjierReport}-273.15>=25?1.38:(${TmaxjierReport}-273.15<=20?0.001:(${VinletReport}>0.1?1.38:0.001));

[0102] After setting the time step and simulation cutoff conditions as needed, click "Calculate" to obtain a fast-charging simulation of the power battery. Compare the charging current extracted from the simulation with the measured data value to obtain a consistency comparison curve between the simulation and the measurement, as shown in the figure. Figure 3 The diagram shows a comparison of simulated and measured current curves provided by an embodiment of the present invention. Figure 3 As can be seen from the figure, the simulation method provided by the present invention has high accuracy, and therefore can efficiently and accurately simulate the fast charging process of power batteries.

[0103] This invention simulates the battery charging process by establishing a finite element model of the battery. In the finite element model, the heat generated during battery charging is applied to the model as a heat source. Then, based on the state of charge and battery temperature, interpolation is performed in the first, second, and third characteristic tables to obtain the real-time charging rate, internal resistance, and open-circuit voltage of the battery, further influencing the actual heat generation. The finite element model is a transient heat transfer simulation model; the simulation does not require knowledge of the internal chemical reaction mechanism of the battery pack, nor does it require inputting chemical parameters. Only the temperature change during charging and its impact on the battery charging rate need to be considered. Compared to existing technologies for simulating the battery charging process, this invention significantly reduces the difficulty of battery simulation and performance analysis, exhibiting good engineering practicality and versatility.

[0104] It should be noted that the steps of the various methods described above are only for clarity. In practice, they can be combined into one step or some steps can be split into multiple steps. As long as they contain the same logical relationship, they are all within the protection scope of this invention. Adding insignificant modifications or introducing insignificant designs to the algorithm or process, without changing the core design of the algorithm and process, are also within the protection scope of this invention.

[0105] Figure 4 This is a functional block diagram of a battery fast charging simulation system provided in an embodiment of the present invention. This system can be applied to… Figure 1 The implementation environment shown is not limited to this system. This system can also be applied to other exemplary implementation environments and specifically configured in other devices. This embodiment does not limit the implementation environment to which the system is applicable.

[0106] like Figure 4 As shown, the system includes an acquisition module 41 and a simulation module 42;

[0107] The acquisition module 41 is used to acquire the finite element model and simulation parameters of the battery;

[0108] The simulation module 42 is used to perform battery fast charging simulation based on the finite element model and the simulation parameters. It executes the following steps: based on the battery state of charge and battery temperature at the start of the current time step, it obtains the charging rate and battery internal resistance by looking up a table; and it updates the battery state of charge and battery temperature based on the time step size, the charging rate, and the battery internal resistance. The simulation steps are repeated until the simulation cutoff condition in the simulation parameters is reached. The simulation cutoff condition is that the battery state of charge reaches a preset threshold or the cumulative charging time reaches a preset time.

[0109] The system's modules can include all the technical features of the aforementioned battery fast charging simulation method, and the usage methods correspond one-to-one. It should be noted that the battery fast charging simulation system provided in the above embodiments and the battery fast charging simulation method provided in the above embodiments belong to the same concept. The specific methods by which each module and unit performs its operations have been described in detail in the method embodiments and will not be repeated here. In practical applications, the battery fast charging simulation method system provided in the above embodiments can, as needed, allocate the above functions to different functional modules, that is, divide the internal structure of the system into different functional modules to complete all or part of the functions described above. This is not a limitation here.

[0110] Embodiments of this application also provide an electronic device, including: one or more processors; and a storage device for storing one or more programs, which, when executed by the one or more processors, cause the electronic device to implement the battery fast charging simulation method provided in the above embodiments.

[0111] Figure 5 A schematic diagram of a computer system suitable for implementing the embodiments of this application is shown. It should be noted that... Figure 5 The computer system 500 of the electronic device shown is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments of this application.

[0112] like Figure 5As shown, the computer system 500 includes a Central Processing Unit (CPU) 501, which can perform various appropriate actions and processes based on programs stored in Read-Only Memory (ROM) 502 or programs loaded from storage portion 508 into Random Access Memory (RAM) 503, such as performing the methods described in the above embodiments. The RAM 503 also stores various programs and data required for system operation. The CPU 501, ROM 502, and RAM 503 are interconnected via a bus 504. An input / output (I / O) interface 505 is also connected to the bus 504.

[0113] The following components are connected to I / O interface 505: an input section 506 including a keyboard, mouse, etc.; an output section 507 including a cathode ray tube (CRT), liquid crystal display (LCD), etc., and speakers, etc.; a storage section 508 including a hard disk, etc.; and a communication section 509 including a network interface card such as a LAN (Local Area Network) card, modem, etc. The communication section 509 performs communication processing via a network such as the Internet. A drive 510 is also connected to I / O interface 505 as needed. Removable media 511, such as a disk, optical disk, magneto-optical disk, semiconductor memory, etc., are installed on drive 510 as needed so that computer programs read from them can be installed into storage section 508 as needed.

[0114] Specifically, according to embodiments of this application, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of this application include a computer program product comprising a computer program carried on a computer-readable medium, the computer program including a computer program for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via communication section 509, and / or installed from removable medium 511. When the computer program is executed by central processing unit (CPU) 501, it performs various functions defined in the system of this application.

[0115] It should be noted that the computer-readable medium shown in the embodiments of this application can be a computer-readable signal medium or a computer-readable storage medium, or any combination of the two. A computer-readable storage medium can be, for example, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of a computer-readable storage medium may include, but are not limited to: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), flash memory, optical fiber, portable compact disc read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this application, a computer-readable signal medium may include a data signal propagated in baseband or as part of a carrier wave, carrying a computer-readable computer program. Such propagated data signals can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. Computer-readable signal media can also be any computer-readable medium other than computer-readable storage media, which can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. The computer program contained on the computer-readable medium can be transmitted using any suitable medium, including but not limited to wireless, wired, etc., or any suitable combination thereof.

[0116] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. Each block in a flowchart or block diagram may represent a module, segment, or portion of code, which contains one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram or flowchart, and combinations of blocks in a block diagram or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0117] The units described in the embodiments of this application can be implemented in software or hardware, and the described units can also be located in a processor. The names of these units do not necessarily limit the specific unit itself.

[0118] Another aspect of this application provides a computer-readable storage medium storing a computer program that, when executed by a computer's processor, causes the computer to perform the battery fast charging simulation method as described above. This computer-readable storage medium may be included in the electronic device described in the above embodiments, or it may exist independently and not incorporated into the electronic device.

[0119] Another aspect of this application provides a computer program product or computer program including computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the computer device to perform the battery fast charging simulation method provided in the various embodiments described above.

[0120] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A simulation method for fast battery charging, characterized in that, include: The finite element model and simulation parameters of the battery are obtained. In the finite element model, field functions for the actual charging current, state of charge (SOC), and battery temperature are established and defined. The actual heat generated during battery charging is applied to the finite element model as a heat source. Based on the SOC and battery temperature, the real-time charging rate, internal resistance, and open-circuit voltage of the battery are obtained through interpolation in the first, second, and third characteristic tables, which also affect the actual heat generated. The finite element model is a transient heat transfer simulation model. Based on the finite element model and the simulation parameters, a fast charging simulation of the battery is performed. Based on the battery state of charge and battery temperature at the start of the current time step, the charging rate and battery internal resistance are obtained by looking up a table. The battery state of charge and battery temperature are updated based on the time step size, the charging rate, and the battery internal resistance. Repeat the above simulation steps until the simulation cutoff condition in the simulation parameters is reached. The simulation cutoff condition is when the battery state of charge reaches a preset threshold or the cumulative charging time reaches a preset time. The step of obtaining the charging rate and battery internal resistance by looking up a table based on the battery state of charge and battery temperature at the start of the current time step includes: Based on the battery state of charge and battery temperature at the start of the current time step, the charging rate and battery internal resistance are determined by looking up a first characteristic table and a second characteristic table. The first characteristic table contains the relationship between the charging rate and the battery state of charge and the battery temperature, and the second characteristic table contains the relationship between the battery internal resistance and the battery temperature and the battery state of charge.

2. The battery fast charging simulation method according to claim 1, characterized in that, The finite element model is obtained through the following steps: Obtain a three-dimensional model of the battery; The three-dimensional model is then subjected to simplification, surface mesh generation, domain division, and volume mesh generation in sequence. A physical connection body is established, and the physical connection body is associated with each domain of the three-dimensional model of the battery after volume meshing to obtain the finite element model of the battery.

3. The battery fast charging simulation method according to claim 1, characterized in that, The simulation parameters include the battery's boundary conditions, material properties, total battery capacity, simulation time step, and simulation cutoff condition.

4. The battery fast charging simulation method according to claim 1, characterized in that, The step of determining the charging rate and battery internal resistance by looking up the first characteristic table and the second characteristic table based on the battery state of charge and the battery temperature at the start of the current time step includes: Get the highest, lowest, and average temperatures of the previous time step; Based on the battery state of charge at the start of the current time step, the first characteristic table, the highest temperature, and the lowest temperature, determine the highest temperature charging rate and the lowest temperature charging rate. The smaller of the highest temperature charging rate and the lowest temperature charging rate is selected as the charging rate. The battery internal resistance is determined based on the second characteristic table, the average temperature, and the battery state of charge.

5. The battery fast charging simulation method according to claim 4, characterized in that, The step of updating the battery state of charge and battery temperature based on the time step size, the charging rate, and the battery internal resistance includes: The charging current at the start of the current time step of the battery is determined based on the total battery capacity and the charging rate. The battery state of charge is updated based on the charging current and the step size of the time step; The battery temperature is updated based on the charging current, the battery internal resistance, and the highest temperature.

6. The battery fast charging simulation method according to claim 5, characterized in that, The step of determining the charging current at the start of the current time step of the battery based on the total battery capacity and the charging rate includes: Based on the battery state of charge at the start of the current time step, the open-circuit voltage is determined by looking up a third characteristic table, which contains the relationship between the battery's open-circuit voltage and the battery state of charge. The charging voltage of the battery is obtained based on the charging current at the end of the previous time step, the battery internal resistance, and the open-circuit voltage. The power limiting current is determined based on the charging power limit and the charging voltage; Based on the total battery capacity and the charging rate, determine the first charging current of the battery at the current time step; The smaller of the power limiting current and the first charging current is selected as the charging current at the start of the current time step.

7. The battery fast charging simulation method according to claim 5, characterized in that, The step of updating the battery temperature based on the charging current, the battery internal resistance, and the highest temperature includes: The heat generation of the battery is calculated based on the charging current and the battery internal resistance. Determine the coolant inlet flow rate based on the highest temperature; The battery temperature is updated based on the battery heat generation and the coolant inlet flow rate.

8. A battery fast charging simulation system, characterized in that, The simulation system, which applies the battery fast charging simulation method as described in any one of claims 1 to 7, comprises: The acquisition module is used to acquire the finite element model and simulation parameters of the battery; The simulation module is used to perform fast charging simulation of the battery based on the finite element model and the simulation parameters. It executes the following steps: based on the battery state of charge and battery temperature at the beginning of the current time step, it obtains the charging rate and battery internal resistance by looking up a table; and it updates the battery state of charge and battery temperature based on the time step size, the charging rate, and the battery internal resistance. The above simulation steps are repeated until the simulation cutoff condition in the simulation parameters is reached. The simulation cutoff condition is that the battery state of charge reaches a preset threshold or the cumulative charging time reaches a preset time.

9. An electronic device, characterized in that, The electronic device includes: One or more processors; A storage device for storing one or more programs that, when executed by one or more processors, cause the electronic device to implement the battery fast charging simulation method as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, It stores a computer program that, when executed by the computer's processor, causes the computer to perform a simulation method for fast battery charging as described in any one of claims 1 to 7.

Images