Economic simulation calculation system and method for new energy vehicle battery management unit

Abstract

The invention discloses an economic simulation calculation system and method for a new energy vehicle battery management unit. The method comprises the following steps: obtaining a battery pack current according to a battery pack charging current, a battery pack discharging current, a real-time SOC of a battery pack and a temperature of the battery pack; obtaining the voltage of the battery pack according to the current of the battery pack, the real-time SOC of the battery pack, the open-circuit voltage of the battery cell, the charging resistance, the discharging resistance and the capacitance; obtaining the temperature of the battery pack according to the PTC heating power, the heat production power of the battery pack and the heat conduction power between the battery and the battery pack shell; the lowest temperature of the battery cell is obtained according to the current environment temperature of the battery pack, the changing temperature of the PTC during heating or cooling, the rising temperature of the battery cell during charging or the rising temperature of the battery cell during discharging; and obtaining the SOC of the battery pack according to the maximum available capacity of the battery cell, the initial SOC of the battery cell and the current of the battery pack. The economical efficiency and the development efficiency of the new energy vehicle battery management system can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of battery simulation, and in particular to an economic simulation calculation system and method for a battery management unit of a new energy vehicle. Background Art

[0002] At present, in the development process of new energy vehicles, the determination of the economy of the battery management unit is to use an ammeter to directly read the economy-related information of the battery management unit after the actual vehicle is produced, and then calibrate the gear shift speed of the new energy vehicle acceleration and deceleration, the maximum power curve points of the engine and motor based on the obtained economy-related information of the battery management unit. Although this method has real signals, it must rely on the actual vehicle, and the economy calculation cannot be performed before the vehicle is assembled. This reduces the calibration efficiency of relevant functional points of new energy vehicles.

[0003] As the development cycle of new energy vehicles continues to shorten, new energy vehicle simulation testing has been widely used in the industry. How to use new energy vehicle simulation testing technology to perform economic simulation of battery management units has become a technical problem that needs to be solved urgently. Summary of the invention

[0004] The purpose of the present invention is to provide an economic simulation calculation system and method for a battery management unit of a new energy vehicle. The present invention can use simulation calculations to accurately obtain the economic results of the battery management unit before the actual vehicle is produced, thereby improving the calibration efficiency of relevant functional points of new energy vehicles.

[0005] To achieve this purpose, the present invention designs an economic simulation calculation system for a new energy vehicle battery management unit, which includes:

[0006] The battery pack current acquisition module performs simulation calculation to obtain the battery pack current based on the battery pack charging current, battery pack discharging current, battery pack real-time SOC (State of Charge) and battery pack temperature;

[0007] The battery pack voltage acquisition module simulates and calculates the battery pack voltage based on the battery pack current, the real-time SOC of the battery pack, the open circuit voltage of the battery cell, the charging resistance of the battery cell, the discharging resistance of the battery cell and the capacitance of the battery cell;

[0008] The battery pack temperature acquisition module simulates and calculates the battery pack temperature based on the PTC (Positive Temperature Coefficient) heating power, the battery pack heat generation power, and the heat conduction power between the battery and the battery pack shell;

[0009] The battery cell minimum temperature acquisition module performs simulation calculation to obtain the battery cell minimum temperature based on the current ambient temperature of the battery pack, the temperature change during PTC heating or cooling, the temperature rise during battery cell charging, or the temperature rise during battery cell discharging.

[0010] The battery pack SOC acquisition module performs simulation calculation based on the maximum available capacity of the battery cell, the initial SOC of the battery cell and the battery pack current to obtain the battery cell SOC and thus the battery pack SOC.

[0011] Preferably, the battery pack current acquisition module is constructed using data modeling software, with the battery pack current calculation variables as the main body, and the vehicle, motor and battery status variables that are included in different vehicle models and have different values ​​in different vehicle models are used as global variables. The main body and the global variables are written into the same file, and a battery pack current calculation model is established and loaded before the battery pack current model is run. A battery pack current calculation unit is implanted in the battery pack current model, and the battery pack current calculation variables are the battery pack charging current, the battery pack discharging current, the real-time SOC of the battery pack and the temperature of the battery pack.

[0012] Preferably, the battery pack voltage acquisition module is built using data modeling software, with the battery pack voltage calculation variables as the main body, and the vehicle, motor and battery status variables that are included in different vehicle models and have different values ​​for different vehicle models are used as global variables. The main body and the global variables are written into the same file, a battery pack voltage calculation model is established and the battery pack voltage model is loaded before running. A battery pack voltage calculation unit is implanted in the battery pack voltage model, and the battery pack voltage calculation variables are the battery pack current, the battery pack real-time SOC, the cell open circuit voltage, the charging resistance, the discharging resistance and the capacitance.

[0013] Preferably, the battery pack temperature acquisition module is built using data modeling software, with the battery pack temperature calculation variables as the main body, and the vehicle, motor and battery status variables that are included in different models and have different values ​​for different models are used as global variables. The main body and the global variables are written into the same file, and a battery pack temperature calculation model is established and loaded before the battery pack temperature model is run. A battery pack temperature calculation unit is implanted in the battery pack temperature model, and the battery pack temperature calculation variables are PTC heating power, battery pack heat generation power, and thermal conductivity power between the battery and the battery pack shell.

[0014] Preferably, the battery cell minimum temperature acquisition module is built using data modeling software, with the battery cell minimum temperature calculation variable as the main body, and the vehicle, motor and battery status variables that are included in different models and have different values ​​for different models are used as global variables. The main body and the global variables are written into the same file, and a battery cell minimum temperature calculation model is established and loaded before the battery cell minimum temperature model is run. A battery cell minimum temperature calculation unit is implanted in the battery cell minimum temperature model, and the battery cell minimum temperature calculation variable is the current ambient temperature of the battery pack, the temperature that changes during heating or cooling of the PTC, the temperature that rises when the battery cell is charged, or the temperature that rises when the battery cell is discharged.

[0015] Preferably, the battery pack SOC acquisition module is built using data modeling software, with the battery pack SOC calculation variables as the main body, and the vehicle, motor and battery status variables that are included in different vehicle models and have different values ​​for different vehicle models are used as global variables. The main body and the global variables are written into the same file, a battery pack SOC calculation model is established and the battery pack SOC model is loaded before running. A battery pack SOC calculation unit is implanted in the battery pack SOC model, and the battery pack SOC calculation variables are the maximum available capacity of the battery cell, the initial SOC of the cell and the battery pack current.

[0016] Beneficial effects of the present invention:

[0017] The present invention provides a simulation environment, which simulates the working conditions of the battery pack under different working conditions by establishing data related to the operation conditions and economy of the actual vehicle. This calibration solution does not rely on the actual vehicle, but uses relevant detection equipment to directly read the economy-related information of the battery management unit, performs calibration work on relevant functional points of new energy vehicles, simulates the battery pack simulation test environment, and is used for the economy calculation of the battery management system. By establishing a simulation environment, the deficiencies of the economy calculation of the battery management system in the prior art are solved, and a method for performing a battery management system before the development of an actual vehicle is provided, which helps to improve the economy and development efficiency of the battery management system of new energy vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the present invention;

[0019] Figure 2 The battery pack SOC acquisition module and the battery pack voltage acquisition module are the battery pack model;

[0020] Figure 3 Thevenin model of battery equivalent circuit;

[0021] Figure 4 Get the charging resistance capacitance and the discharging resistance capacitance;

[0022] Figure 5It is a battery pack model. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0025] Example 1

[0026] An economic simulation calculation system for a battery management unit of a new energy vehicle, such as Figure 1 , which includes:

[0027] The battery pack current acquisition module performs simulation calculation to obtain the battery pack current based on the battery pack charging current, battery pack discharging current, real-time SOC of the battery pack and the temperature of the battery pack;

[0028] The battery pack voltage acquisition module simulates and calculates the battery pack voltage based on the battery pack current, battery pack real-time SOC, cell open circuit voltage, charging resistance, discharge resistance and capacitance, such as Figure 2 ;

[0029] The battery pack temperature acquisition module simulates and calculates the battery pack temperature based on the PTC heating power, the battery pack heat generation power, and the heat conduction power between the battery and the battery pack shell;

[0030] The battery cell minimum temperature acquisition module performs simulation calculation to obtain the battery cell minimum temperature based on the current ambient temperature of the battery pack, the temperature change during PTC heating or cooling, the temperature rise during battery cell charging, or the temperature rise during battery cell discharging.

[0031] The battery pack SOC acquisition module simulates and calculates the battery cell SOC based on the maximum available capacity of the battery cell, the initial SOC of the battery cell and the battery pack current to obtain the battery pack SOC, such as Figure 2 .

[0032] In the above technical solution, the battery pack current acquisition module is built using MATLAB (Matrix Laboratory) software. During the construction, the battery pack current calculation variables are taken as the main body, and the vehicle, motor and battery state variables that are included in different models and have different values ​​for different models are used as global variables. The main body and the global variables are written into the same file, and a battery pack current calculation model is established and loaded before the battery pack current model is run. A battery pack current calculation unit is implanted in the battery pack current model, and the battery pack current calculation variables are the battery pack charging current, the battery pack discharging current, the real-time SOC of the battery pack and the temperature of the battery pack.

[0033] In the above technical solution, the battery pack voltage acquisition module is built using MATLAB software. During the construction, the battery pack voltage calculation variables are taken as the main body, and the vehicle, motor and battery status variables that are included in different models and have different values ​​for different models are taken as global variables. The main body and the global variables are written into the same file, and a battery pack voltage calculation model is established and loaded before the battery pack voltage model is run. A battery pack voltage calculation unit is implanted in the battery pack voltage model. The battery pack voltage calculation variables are the battery pack current, the battery pack real-time SOC, the cell open circuit voltage, the charging resistance, the discharging resistance and the capacitance.

[0034] In the above technical solution, the battery pack temperature acquisition module is built using MATLAB software. During the construction, the battery pack temperature calculation variables are taken as the main body. The vehicle, motor and battery status variables that are included in different models and have different values ​​for different models are used as global variables. The main body and the global variables are written into the same file, and a battery pack temperature calculation model is established and loaded before the battery pack temperature model is run. A battery pack temperature calculation unit is implanted in the battery pack temperature model. The battery pack temperature calculation variables are PTC heating power, battery pack heat generation power, and thermal conductivity power between the battery and the battery pack shell.

[0035] In the above technical scheme, the battery cell minimum temperature acquisition module is built using MATLAB software. During the construction, the battery cell minimum temperature calculation variable is taken as the main body, and the vehicle, motor and battery state variables that are included in different models and have different values ​​for different models are used as global variables. The main body and the global variables are written into the same file, and a battery cell minimum temperature calculation model is established and loaded before the battery cell minimum temperature model is run. A battery cell minimum temperature calculation unit is implanted in the battery cell minimum temperature model. The battery cell minimum temperature calculation variable is the current ambient temperature of the battery pack, the temperature that changes during heating or cooling of the PTC, the temperature that rises when the battery cell is charged, or the temperature that rises when the battery cell is discharged.

[0036] In the above technical scheme, the battery pack SOC acquisition module is built using MATLAB software. During the construction, the battery pack SOC calculation variables are taken as the main body, and the vehicle, motor and battery state variables that are included in different models and have different values ​​for different models are used as global variables. The main body and the global variables are written into the same file, and a battery pack SOC calculation model is established and loaded before the battery pack SOC model is run. A battery pack SOC calculation unit is implanted in the battery pack SOC model, and the battery pack SOC calculation variables are the maximum available capacity of the battery cell, the initial SOC of the cell and the battery pack current.

[0037] In the above technical solution, the battery pack current calculation formula included in the battery pack current calculation unit is:

[0038] Battery pack current = (battery pack charging current or battery pack discharging current) + correction value based on the real-time SOC of the battery pack and the temperature of the battery pack.

[0039] The correction value is obtained by looking up a table based on the real-time SOC of the battery pack, the temperature of the battery pack, the total charging capacity of the battery, and the total discharging capacity of the battery calculated by the whole vehicle model.

[0040] In the above technical solution, the vehicle economy is evaluated by calculating the battery SOC change. The battery pack current economy is reflected in the fact that the charging and discharging of the power battery pack during the driving of the vehicle are both expressed by current. The current at each moment is integrated over time to obtain the change in power at that time. Based on the vehicle battery pack SOC and power change, the power of the vehicle at the target moment is obtained to evaluate the vehicle economy.

[0041] In the above technical solution, there is loss when charging and discharging the battery pack. Accurately calculating the loss can promptly remind the owner to charge the power battery when the power is low during vehicle operation, to avoid the situation where the vehicle suddenly runs out of power or breaks down while driving on the road.

[0042] In the above technical solution, the battery pack voltage calculation formula included in the battery pack voltage calculation unit is:

[0043]

[0044] Among them, OCV, R0, R1 and C1 are obtained by looking up the table based on the current ambient temperature and the real-time SOC of the battery pack; U1 represents the voltage of the RC part, V Cell represents the cell terminal voltage, OCV represents the cell open circuit voltage, R0 represents the charging resistance, R1 represents the discharge resistance, C1 represents the battery cell capacitance, I represents the battery pack current, represents the voltage of the equivalent circuit RC, and T represents the average temperature of the battery cell. , where the table for OCV, R0, R1, and C1 is a two-dimensional table of temperature and soc based on experimental data.

[0045] U1 is discretized by solving the differential equation as follows:

[0046]

[0047] Among them, U 1,K represents K time U1, U 1,K+1 represents U1 at time K+1, e is a natural constant, and Ts represents the sampling time of the controller.

[0048] In the above technical solution, the RC equivalent circuit battery model is a model used to simplify circuit analysis, such as Figure 3 , using an ideal voltage source and an internal resistance to represent the characteristics of the battery. This model has important applications in circuit analysis and battery performance evaluation, but it is important to note the differences between its simplified characteristics and actual batteries. By using the equivalent circuit battery model properly, it is easier to analyze circuit behavior and improve the efficiency of circuit design and battery management.

[0049] In the above technical solution, the battery pack temperature calculation formula included in the battery pack temperature calculation unit is:

[0050]

[0051] Among them, T battery Indicates the battery pack temperature; Q PTC Indicates PTC heating power; Q battery Indicates the heat generation power of the battery pack; Q conductive represents the heat transfer coefficient between the battery cell and the battery pack shell; C represents the heat transfer coefficient between the battery cell and the battery pack shell; battery Indicates the specific heat capacity of the battery pack; M battery Indicates the quality of the battery pack; T pack Indicates the battery pack shell temperature;

[0052] Battery pack shell temperature calculation:

[0053]

[0054] Among them, T pack is the battery pack temperature; h is the convection heat transfer coefficient between the battery cell and the battery cell shell; A represents the heat exchange area between the battery pack shell and the outside air; T air Indicates the ambient temperature of the battery pack; C pack Indicates the specific heat capacity of the battery pack; M pack Indicates the quality of the battery pack shell; T ini_pack Indicates the initial temperature of the battery pack shell;

[0055] Calculation of heat generation of battery cells:

[0056] Q battery =Q Cell =∑I 2 R(T,SOC)

[0057] Among them, I represents the current, R represents the internal resistance of the battery cell, T represents the temperature of the battery cell, SOC represents the battery cell charge, Q cell Indicates that the battery cell is generating heat.

[0058] In the above technical solution, the vehicle economy is evaluated by calculating the battery SOC change. The battery pack temperature economy is reflected in the fact that the temperature of the battery pack has a direct impact on the battery power. At normal temperature, the total power of the battery will be greater than the total power of the battery under the same conditions at low temperature.

[0059] In the above technical solution, temperature has a great impact on the power battery pack. For the same battery pack, the power at low temperature will be lower than that at normal temperature. When the temperature is too low, for example -40℃, there is no way to discharge to the outside world and provide power.

[0060] In the above technical solution, the battery cell minimum temperature calculation formula included in the battery cell minimum temperature calculation unit is:

[0061] The lowest temperature of the battery cell = min (the temperature of the first battery cell, the temperature of the second battery cell...the temperature of the 100th battery cell)

[0062] The temperature of each battery cell = the current ambient temperature of the battery pack + (the temperature of the battery cell rising during charging or the temperature of the battery cell rising during discharging) + the temperature change during heating or cooling of the PTC.

[0063] In the above technical solution, the vehicle economy is evaluated by calculating the battery SOC change. The economy of the battery cell minimum temperature is reflected in the direct impact of the battery cell minimum temperature on the battery power. A sensor is placed between every two battery cells, and the average temperature of the battery cell is used as the temperature of the battery pack. When the battery pack temperature is low, the total power will be lower than that of a normal temperature battery pack under the same conditions.

[0064] In the above technical solution, the battery pack SOC calculation formula included in the battery pack SOC calculation unit is:

[0065] SOC Pack =sum(SOC1(t),SOC2(t)……SOC 96 (t))

[0066] Among them, SOC Pack Indicates battery pack SOC, SOC 96 (t) represents the charge of the 96th cell, SOC pack Add up the power of all the batteries. The number of batteries in this test is 96. Sum refers to the sum operation.

[0067]

[0068] Among them, the value of I is specified as discharging current is positive and charging current is negative; Q(T) is the maximum available capacity of the battery cell obtained by temperature lookup based on the experimental data of the battery; SOC0 represents the initial SOC of the battery cell; ∫I dt represents the integral of the battery pack current per second in a driving cycle of the vehicle.

[0069] In the above technical solution, the vehicle economy is evaluated by calculating the battery SOC change, and the battery pack SOC calculation directly reflects the battery economy.

[0070] In the above technical solution, the precise power of each battery cell is added together to know the power of the entire power battery pack more accurately. This method can simulate in real time the economic decline of the battery pack after the vehicle has been running for 5-10 years. The power is less when it is fully charged than when it is just out of the factory, which means that the storage SOC of some battery cells has decreased. For commercial vehicles, the SOC stored in different battery cells becomes smaller, and the output current will also be different. If a circulation current is formed between battery cells, it will also affect the branch current output in the entire battery pack. All these effects need to be simulated using the SOC of the power battery cell.

[0071] In the above technical solution, the temperature calculation of the battery pack includes two parts: the heat generated by the battery pack under different working conditions and the heat transfer between the cells. The two work together and are calculated based on the initial temperature T of the battery pack. ini_battery , calculate the real-time temperature of the battery pack.

[0072] Battery pack temperature calculation formula:

[0073]

[0074] Among them, T battery Indicates the battery pack temperature; Q PTC Indicates PTC heating power; Q battery Indicates the heat generation power of the battery; Q conductive represents the heat transfer power between the battery and the battery pack shell; H is the heat transfer coefficient between the battery and the battery pack shell; C battery : specific heat capacity of the battery; M battery :Battery quality; T pack is the battery pack shell temperature; Tini_battery represents the initial battery temperature.

[0075] In the above technical solution, the accurate temperature calculation of the power battery pack has an impact on the estimation of the power battery pack's actual power. Therefore, it is of great significance to calculate the real-time temperature of the battery pack. Among them, Tini_battery is a calibration value. During simulation, it is necessary to simulate the environment of the vehicle. This variable is taken out separately. Each time the simulation is performed, only the value needs to be assigned, which will not cause major changes to the simulation model and improve the platform portability of the simulation model.

[0076] In the above technical solution, the calculation of charging resistance and capacitance and discharging resistance and capacitance is based on test data, and parameter identification is performed, and the resistance and capacitance in the charging state and the resistance and capacitance in the discharging state are obtained by looking up tables respectively.

[0077] In the above technical solution, the specific calculation method of the charging resistance, discharging resistance and capacitance is:

[0078] Average value of charging resistance or discharging resistance = AVG (battery pack 1 resistance, battery pack 2 resistance, ... battery pack N resistance)

[0079] Average value of charging resistance or discharging capacitance = AVG (resistance of battery pack 1, resistance of battery pack 2, ... resistance of battery pack N)

[0080] Get the experimental parameters of resistance and capacitance, calculate the average value of N groups of experimental data (AVG stands for average) through the test of N battery packs, and correct the battery's charging resistance, discharge resistance and capacitance according to the actual vehicle data to obtain the final charging resistance, discharge resistance and capacitance.

[0081] Get the experimental parameters of resistance and capacitance, such as Figure 4 Through the test of N battery packs, the battery packs are fully left to stand at different ambient temperatures to make the battery cell temperature consistent with the ambient temperature. After charging and discharging tests, N groups of test data are obtained, and the average value of the N groups of experimental data is calculated. The difference between each test data and the average value is compared. The first 80% of the data with the smallest difference is taken as valid data, and the other 20% of the data is discarded as invalid data.

[0082] Take the mileage from 0 to the first maintenance mileage of the vehicle as the first correction interval, and the vehicle's cruising range to the first maintenance mileage of the vehicle as a node. Use the actual vehicle charging and discharging data of the same battery as the first basic unit of calculation, and test the charging resistance, discharge resistance, and capacitance of N actual vehicle samples to obtain a normal distribution graph. First, take the data value with the largest distribution as the center axis, remove the 20% of the data farthest from the center axis, and take the remaining 80% of the data as the second basic unit of calculation, and take the average of these 80% of the data as the charging resistance, discharge resistance and capacitance of the power battery of the vehicle to the first maintenance mileage. Repeat the operation to obtain other charging resistances, discharge resistances, and capacitances.

[0083] In the above technical solution, the vehicle variables include acceleration time, climbing grade, driving resistance, and transmission ratio of the transmission system; the motor variables include motor speed, motor torque, and motor power; the battery state variables include charging resistance, discharge resistance, capacitance, charging current, and discharge current at different temperatures.

[0084] In the above technical solution, the temperature lookup table is: solidify the experimental data, and obtain a two-dimensional table based on the weighted average of multiple experiments. The weighting principle is determined according to the results of the sample test: if 8 experimental results are consistent among 10 samples, the weight of this result is 0.8 higher, and the weight of the values ​​of the other two samples is 0.2 lower, and the experimental data is obtained.

[0085] Example 2

[0086] A method for simulating the economic performance of a battery management unit for a new energy vehicle, such as Figure 5 The battery pack current acquisition module is built using MATLAB software. During the construction, the battery pack current calculation variables are taken as the main body. The vehicle, motor and battery state variables that are included in different models and have different values ​​for different models are used as global variables. The main body and the global variables are written into the same file, and a battery pack current calculation model is established and loaded before the battery pack current model is run. A battery pack current calculation unit is implanted in the battery pack current model. The battery pack current calculation variables are the battery pack charging current, the battery pack discharging current, the real-time SOC of the battery pack and the temperature of the battery pack.

[0087] The battery pack voltage acquisition module is built using MATLAB software. During the construction, the battery pack voltage calculation variables are taken as the main body. The vehicle, motor and battery status variables that are included in different models and have different values ​​for different models are used as global variables. The main body and the global variables are written into the same file, and a battery pack voltage calculation model is established and loaded before the battery pack voltage model is run. A battery pack voltage calculation unit is implanted in the battery pack voltage model. The battery pack voltage calculation variables are the battery pack current, the battery pack real-time SOC, the battery cell open circuit voltage, the battery cell charging resistance, the battery cell discharge resistance and the battery cell capacitance.

[0088] The battery pack temperature acquisition module is built using MATLAB software. During the construction, the battery pack temperature calculation variables are taken as the main body. The vehicle, motor and battery status variables that are included in different models and have different values ​​for different models are used as global variables. The main body and the global variables are written into the same file, and a battery pack temperature calculation model is established and loaded before the battery pack temperature model is run. A battery pack temperature calculation unit is implanted in the battery pack temperature model. The battery pack temperature calculation variables are PTC heating power, battery pack heat generation power, and thermal conductivity power between the battery and the battery pack shell.

[0089] The battery cell minimum temperature acquisition module is built using MATLAB software. During the construction, the battery cell minimum temperature calculation variable is taken as the main body, and the vehicle, motor and battery state variables that are included in different models and have different values ​​for different models are used as global variables. The main body and the global variables are written into the same file, and a battery cell minimum temperature calculation model is established and loaded before the battery cell minimum temperature model is run. A battery cell minimum temperature calculation unit is implanted in the battery cell minimum temperature model. The battery cell minimum temperature calculation variable is the current ambient temperature of the battery pack, the temperature that changes during heating or cooling of the PTC, the temperature that rises when the battery cell is charged, or the temperature that rises when the battery cell is discharged.

[0090] The battery pack SOC acquisition module is built using MATLAB software. During the construction, the battery pack SOC calculation variables are taken as the main body. The vehicle, motor and battery status variables that are included in different models and have different values ​​for different models are used as global variables. The main body and the global variables are written into the same file, and a battery pack SOC calculation model is established and loaded before the battery pack SOC model is run. A battery pack SOC calculation unit is implanted in the battery pack SOC model. The battery pack SOC calculation variables are the maximum available capacity of the battery cell, the initial SOC of the cell and the battery pack current.

[0091] The specific calculation unit of economic simulation includes the following steps:

[0092] The battery pack current is obtained by simulation calculation based on the battery pack charging current, battery pack discharging current, real-time SOC of the battery pack and the temperature of the battery pack;

[0093] The battery pack voltage is obtained by simulation calculation based on the battery pack current, battery pack real-time SOC, cell open circuit voltage, charging resistance, discharge resistance and capacitance;

[0094] The battery pack temperature is obtained by simulation calculation based on the PTC heating power, the heat generation power of the battery pack, and the heat conduction power between the battery and the battery pack shell;

[0095] The lowest temperature of the battery cell is obtained by simulation calculation based on the current ambient temperature of the battery pack, the temperature change during heating or cooling of the PTC, the temperature rise during charging of the battery cell, or the temperature rise during discharging of the battery cell.

[0096] The battery cell SOC is obtained by simulation calculation based on the maximum available capacity of the battery cell, the initial SOC of the battery cell and the battery pack current, thereby obtaining the battery pack SOC.

[0097] Example 3

[0098] A computer program product includes a computer program, and when the computer program is executed by a processor, the system described in Example 2 is implemented.

[0099] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An economic simulation calculation system for a new energy vehicle battery management unit, characterized in that: It includes: The battery pack current acquisition module performs simulation calculation to obtain the battery pack current based on the battery pack charging current, battery pack discharging current, real-time SOC of the battery pack and the temperature of the battery pack; The battery pack voltage acquisition module simulates and calculates the battery pack voltage based on the battery pack current, the real-time SOC of the battery pack, the open circuit voltage of the battery cell, the charging resistance of the battery cell, the discharging resistance of the battery cell and the capacitance of the battery cell; The battery pack temperature acquisition module simulates and calculates the battery pack temperature based on the PTC heating power, the battery pack heat generation power, and the heat conduction power between the battery and the battery pack shell; The battery cell minimum temperature acquisition module performs simulation calculation to obtain the battery cell minimum temperature based on the current ambient temperature of the battery pack, the temperature change during PTC heating or cooling, the temperature rise during battery cell charging, or the temperature rise during battery cell discharging. The battery pack SOC acquisition module performs simulation calculation based on the maximum available capacity of the battery cell, the initial SOC of the battery cell and the battery pack current to obtain the battery cell SOC and thus the battery pack SOC.

2. The economic calculation system of the new energy vehicle battery management unit according to claim 1 is characterized in that: The battery pack current acquisition module is built using data modeling software. During the construction, the battery pack current calculation variables are taken as the main body. The vehicle, motor and battery status variables that are included in different models and have different values ​​in different models are used as global variables. The main body and the global variables are written into the same file, and a battery pack current calculation model is established and loaded before the battery pack current model is run. A battery pack current calculation unit is implanted in the battery pack current model. The battery pack current calculation variables are the battery pack charging current, the battery pack discharging current, the real-time SOC of the battery pack and the temperature of the battery pack.

3. The economic calculation system of the new energy vehicle battery management unit according to claim 1 is characterized in that: The battery pack voltage acquisition module is built using data modeling software. During the construction, the battery pack voltage calculation variables are taken as the main body. The vehicle, motor and battery status variables that are included in different models and have different values ​​for different models are taken as global variables. The main body and the global variables are written into the same file, and a battery pack voltage calculation model is established and loaded before the battery pack voltage model is run. A battery pack voltage calculation unit is implanted in the battery pack voltage model. The battery pack voltage calculation variables are the battery pack current, the battery pack real-time SOC, the cell open circuit voltage, the charging resistance, the discharging resistance and the capacitance.

4. The economic calculation system of the new energy vehicle battery management unit according to claim 1, characterized in that: The battery pack temperature acquisition module is built using data modeling software. During the construction, the battery pack temperature calculation variables are taken as the main body. The vehicle, motor and battery status variables that are included in different models and have different values ​​for different models are used as global variables. The main body and the global variables are written into the same file, and a battery pack temperature calculation model is established and loaded before the battery pack temperature model is run. A battery pack temperature calculation unit is implanted in the battery pack temperature model. The battery pack temperature calculation variables are PTC heating power, battery pack heat generation power, and thermal conductivity power between the battery and the battery pack shell.

5. The economic calculation system of the new energy vehicle battery management unit according to claim 1, characterized in that: The battery cell minimum temperature acquisition module is built using data modeling software. During the construction, the battery cell minimum temperature calculation variable is taken as the main body, and the vehicle, motor and battery state variables that are included in different models and have different values ​​for different models are used as global variables. The main body and the global variables are written into the same file, and a battery cell minimum temperature calculation model is established and loaded before the battery cell minimum temperature model is run. A battery cell minimum temperature calculation unit is implanted in the battery cell minimum temperature model. The battery cell minimum temperature calculation variable is the current ambient temperature of the battery pack, the temperature that changes during heating or cooling of the PTC, the temperature that rises when the battery cell is charged, or the temperature that rises when the battery cell is discharged.

6. The economic calculation system of the new energy vehicle battery management unit according to claim 1, characterized in that: The battery pack SOC acquisition module is built using data modeling software. During the construction, the battery pack SOC calculation variables are taken as the main body. The vehicle, motor and battery status variables that are included in different models and have different values ​​for different models are used as global variables. The main body and the global variables are written into the same file, and a battery pack SOC calculation model is established and loaded before the battery pack SOC model is run. A battery pack SOC calculation unit is implanted in the battery pack SOC model. The battery pack SOC calculation variables are the maximum available capacity of the battery cell, the initial SOC of the cell and the battery pack current.

7. The economic calculation system of the new energy vehicle battery management unit according to claim 2, characterized in that: The battery pack current calculation formula included in the battery pack current calculation unit is: Battery pack current = (battery pack charging current or battery pack discharging current) + correction value based on the real-time SOC of the battery pack and the temperature of the battery pack.

8. The economic calculation system of the new energy vehicle battery management unit according to claim 3 is characterized in that: The battery pack voltage calculation formula included in the battery pack voltage calculation unit is: Among them, OCV, R0, R1 and C1 are obtained by looking up the table based on the current ambient temperature and the real-time SOC of the battery pack; U1 represents the voltage of the RC part, V Cell represents the cell terminal voltage, OCV represents the cell open circuit voltage, R0 represents the charging resistance, R1 represents the discharge resistance, C1 represents the battery cell capacitance, I represents the battery pack current, represents the voltage of RC in the equivalent circuit, and T represents the average temperature of the battery cell.

9. The economic calculation system of the new energy vehicle battery management unit according to claim 4, characterized in that: The battery pack temperature calculation formula included in the battery pack temperature calculation unit is: Among them, T battery Indicates the battery pack temperature; Q PTC Indicates PTC heating power; Q battery Indicates the heat generation power of the battery pack; Q conductive represents the heat transfer coefficient between the battery cell and the battery pack shell; C represents the heat transfer coefficient between the battery cell and the battery pack shell; battery Indicates the specific heat capacity of the battery pack; M battery Indicates the quality of the battery pack; T pack Indicates the battery pack case temperature.

10. The economic calculation system of the new energy vehicle battery management unit according to claim 5, characterized in that: The battery cell minimum temperature calculation unit includes a battery cell minimum temperature calculation formula as follows: The lowest temperature of the battery cell = min (the temperature of the first battery cell, the temperature of the second battery cell...the temperature of the Nth battery cell) The temperature of each battery cell = the current ambient temperature of the battery pack + (the temperature of the battery cell rising during charging or the temperature of the battery cell rising during discharging) + the temperature change during heating or cooling of the PTC.

11. The economic calculation system of the new energy vehicle battery management unit according to claim 6, characterized in that: The battery pack SOC calculation formula included in the battery pack SOC calculation unit is: SOC Peck =sum(SOC1(t),SOC2(t)……SOC m (t)) Among them, SOC pack Indicates battery pack SOC, SOC m (t) represents the SOC of the mth cell; Wherein, Q(T) represents the maximum available capacity of the battery cell obtained by temperature lookup based on the experimental data of the battery; SOC0 represents the initial SOC of the battery cell; ∫Idt represents the integral of the battery pack current per second during a driving cycle of the vehicle.

12. The economic calculation system of the new energy vehicle battery management unit according to claim 4, characterized in that: The battery pack temperature calculation formula included in the battery pack temperature calculation unit is: Among them, T battery Indicates the battery pack temperature; Q PTC Indicates PTC heating power; Q battery Indicates the heat generation power of the battery pack; Q conductive represents the heat transfer coefficient between the battery cell and the battery pack shell; C represents the heat transfer coefficient between the battery cell and the battery pack shell; battery Indicates the specific heat capacity of the battery pack; M battert Indicates the quality of the battery pack; T pack Indicates the battery pack shell temperature; Tini_battery indicates the initial battery temperature.

13. An economic simulation calculation method for a new energy vehicle battery management unit according to the system of claim 1, characterized in that: It follows the steps: The battery pack current is obtained by simulation calculation based on the battery pack charging current, battery pack discharging current, real-time SOC of the battery pack and the temperature of the battery pack; The battery pack voltage is obtained by simulation calculation based on the battery pack current, the real-time SOC of the battery pack, the open circuit voltage of the battery cell, the charging resistance of the battery cell, the discharging resistance of the battery cell and the capacitance of the battery cell; The battery pack temperature is obtained by simulation calculation based on the PTC heating power, the heat generation power of the battery pack, and the heat conduction power between the battery and the battery pack shell; The lowest temperature of the battery cell is obtained by simulation calculation based on the current ambient temperature of the battery pack, the temperature change during heating or cooling of the PTC, the temperature rise during charging of the battery cell, or the temperature rise during discharging of the battery cell. The battery cell SOC is obtained by simulation calculation based on the maximum available capacity of the battery cell, the initial SOC of the battery cell and the battery pack current, thereby obtaining the battery pack SOC.

14. A computer program product comprising a computer program, characterized in that The computer program implements the steps of the method according to claim 13 when executed by a processor.

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