Device and method for simulating performance of battery pack by battery cell based on heat transfer environment migration

Abstract

The invention provides a device and method for simulating the performance of a battery pack by a battery cell based on heat transfer environment migration, and relates to the technical field of battery pack performance simulation. The device comprises a wrapping structural part, a first compartment and at least two second compartments and third compartments adjacent to the first compartment are arranged in the wrapping structural part, and heat insulation materials are arranged between the first compartment and the second compartments and between the first compartment and the third compartments; the first compartment is used for placing a tested battery cell, and auxiliary battery cells are arranged in the second compartment and the third compartment; the tested battery cell is a basic unit forming the tested battery pack, and the performance of the tested battery cell is the same as that of the auxiliary battery cell. According to the invention, the performance of the tested battery pack is accurately simulated without actual measurement, and the problem of poor reference caused by the difference between the laboratory environment and the environment in the battery pack can be avoided.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of battery pack performance simulation and prediction, and particularly relates to a device and method for simulating battery pack performance of a battery cell based on heat transfer environment migration. BACKGROUND

[0002] Lithium ion batteries, as a driving force source of new energy vehicles, have been widely used in the field of new energy vehicles due to their green environmental protection, recyclability, small size and other characteristics. Testing and evaluating the performance of the battery is an important research and development activity in the battery development stage.

[0003] In the laboratory, a single battery cell is usually connected to a charge and discharge cabinet to perform specific charging and discharging, so as to evaluate various performances of the battery cell. Figure 1 As shown in the figure, it is a common laboratory test bench schematic diagram, wherein the positive and negative pole positions of the battery cell are welded with busbars for wiring, the busbars are connected with the charge and discharge cabinet wire harness through bolts or mechanical clamping, and the whole battery cell is placed in an environmental box, and the environmental box used for testing usually has a strong forced convection air.

[0004] The above test conditions in the laboratory will cause the measured battery cell to have a strong heat exchange with the surrounding environmental box, and these conduction paths include convective heat transfer between the surface of the battery cell and the flowing air, heat conduction between the battery cell and the connecting wire harness, and heat conduction between the environmental box support placed at the bottom of the battery cell. The above heat conduction process will cause the temperature of the battery cell in various tests to be strongly affected by the above factors.

[0005] However, the real performance of the battery cell in the pack is usually quite different from the laboratory test results, and the specific reason is that the heat dissipation environment of the battery cell in the pack is quite different from the laboratory test conditions, so that when the laboratory test results of the single battery cell are used for performance prediction of the pack, the reference is poor. SUMMARY

[0006] In order to overcome the above-mentioned deficiencies of the prior art, the application provides a device and a method for simulating the performance of a battery pack based on heat transfer environment migration, which applies the idea of analogy migration to a measured battery pack and a known performance battery pack with the same structure or similar structure, takes the temperature rise curves of the highest temperature cell and the lowest temperature cell in the known performance battery pack as calibration objects, applies the cell units in the known performance battery pack to the designed device, calibrates the parameter combination of the heat transfer device in the device based on the calibration objects, and applies the calibrated parameter combination to the cells in the measured battery pack, so as to simulate the performance of the measured battery pack and predict the temperatures of the highest temperature cell and the lowest temperature cell in the measured battery pack without actual measurement and the problem of reference difference caused by the difference between the laboratory environment and the environment in the battery pack.

[0007] In order to achieve the above-mentioned purpose, one or more embodiments of the application provide the following technical solutions: The first aspect of the application provides a device for simulating the performance of a battery pack based on heat transfer environment migration.

[0008] The device for simulating the performance of a battery pack based on heat transfer environment migration comprises a wrapping structure, a first compartment and at least two second compartments and third compartments adjacent to the first compartment are arranged inside the wrapping structure, and heat insulation materials are arranged between the first compartment and the second compartment and the third compartment; the first compartment is used for placing a measured cell, and auxiliary cells are arranged in the second compartment and the third compartment; the measured cell and the auxiliary cell are basic units constituting a measured battery pack.

[0009] As an optional technical solution, the wrapping structure is externally provided with an air cover.

[0010] As an optional technical solution, the wrapping structure is a wooden board or a metal plate.

[0011] As an optional technical solution, the heat insulation material is foam or aerogel.

[0012] As an optional technical solution, a busbar row is further arranged in the wrapping structure, and the busbar row is used for connecting adjacent measured cells and auxiliary cells.

[0013] As an optional technical solution, the wrapping structure is a semi-closed structure with an open top, and the top of the first compartment, the second compartment and the third compartment is open.

[0014] The second aspect of the application provides a method for simulating the performance of a battery pack based on heat transfer environment migration.

[0015] The method for simulating the performance of a battery pack based on heat transfer environment migration comprises the following steps: Obtaining the temperature rise data of the No. 1 battery pack during the charging and discharging process, selecting the temperature rise curve of the highest temperature cell and the lowest temperature cell, and marking them as the first temperature rise curve and the second temperature rise curve respectively; Placing the No. 1 cell into the first compartment of the device for simulating the performance of the cell battery pack based on the heat transfer environment migration according to any one of claims 1-6; The thickness and thermal conductivity of the wrapping structure, and the thickness and thermal conductivity of the thermal insulation material are combined as parameters; Adjusting the parameter combination so that the temperature distribution of the No. 1 cell in the first compartment is close to the first temperature rise curve under the same current condition, and obtaining the first parameter combination; Similarly, the temperature distribution of the No. 1 cell in the first compartment is close to the second temperature rise curve, and the second parameter combination is obtained; Placing the No. 2 cell constituting the No. 2 battery pack into the first compartment, and applying the first parameter combination and the second parameter combination under the same current condition, and measuring the highest temperature and the lowest temperature of the No. 2 cell, which are the simulated highest temperature cell and the lowest temperature cell of the No. 2 battery pack.

[0016] As an optional technical solution, the structure of the No. 2 battery pack and the No. 1 battery pack is the same.

[0017] As an optional technology, obtaining the cell temperature rise data during the cyclic charging and discharging process of the No. 1 battery pack, specifically including: Applying a periodic pulse current to the No. 1 battery pack to perform cyclic charging and discharging, and the charge and discharge amounts are equal, and measuring the temperature rise data of the No. 1 cell during the process; When the temperature change rate of the No. 1 cell is less than the set value, it is considered that the system has reached an equilibrium state, and the charging and discharging cycle is stopped.

[0018] As an optional technology, applying the first parameter combination and the second parameter combination respectively, specifically: Respectively setting the thickness and thermal conductivity of the wrapping structure, and the thickness and thermal conductivity of the thermal insulation material according to the first parameter combination and the second parameter combination.

[0019] The above one or more technical solutions have the following beneficial effects: The application provides a device and method for simulating battery pack performance based on heat transfer environment migration, which applies the migration and analogy idea to unknown performance battery packs with the same or similar structure and known performance battery packs, takes the temperature rise curves of the highest temperature battery cell and the lowest temperature battery cell in the known performance battery pack as calibration objects, applies the battery cell unit in the known performance battery pack to the designed device, calibrates the parameter combination of the heat transfer device in the device based on the calibration objects, and applies the calibrated parameter combination to the battery cell of the unknown performance battery pack, so that the performance of the unknown performance battery pack can be simulated, and the temperatures of the highest temperature battery cell and the lowest temperature battery cell of the unknown performance battery pack can be predicted without actual measurement, and the problem of poor reference caused by the difference between the laboratory environment and the battery pack environment can be avoided.

[0020] The device for simulating battery pack performance based on heat transfer environment migration is designed, the second compartment and the third compartment adjacent to the first compartment are arranged in the wrapping structure, and the heat insulation material is arranged between the first compartment and the second compartment and the third compartment, the thickness and the thermal conductivity of the wrapping structure and the thickness and the thermal conductivity of the heat insulation material are taken as the parameter combination during subsequent parameter adjustment, and then the parameter combination is calibrated by using the calibration objects (the temperature rise curves of the highest temperature battery cell and the lowest temperature battery cell), the similarity migration of the heat transfer environment material in the internal temperature rise process of different battery packs with the same or similar structure is actually realized, and the performance of the unknown performance battery pack can be reasonably and scientifically simulated and predicted.

[0021] The advantages of the additional aspects of the application will be partially given in the following description, partially become obvious from the following description, or be understood by the practice of the application. BRIEF DESCRIPTION OF DRAWINGS

[0022] The accompanying drawings, which form a part of the present description, are included to provide a further understanding of the application, and are incorporated herein for explanation by illustrating a preferred embodiment of the present application.

[0023] Figure 1 It is a schematic diagram of the battery cell test bench in the prior art.

[0024] Figure 2 It is a schematic diagram of the internal structure of the traditional battery pack.

[0025] Figure 3 It is a schematic diagram of the top view and sectional structure of the device in embodiment one.

[0026] Figure 4 It is a schematic diagram of the structure of pack A and pack B in embodiment two.

[0027] Figure 5Temperature profile of the highest temperature cell and the lowest temperature cell in Pack A for Example 2.

[0028] Figure 6 Method flow chart for Example 2.

[0029] Figure 7 Periodic pulsed current profile applied to Pack A.

[0030] Figure 8 Temperature results of the pack A duty cycle test.

[0031] 1, cell; 2, connection harness; 3, busbar; 4, battery pack; 5, wrapping structure; 6, first compartment; 7, second compartment; 8, third compartment; 9, thermal insulation material; 10, air baffle. DETAILED DESCRIPTION

[0032] It should be noted that the following detailed description is merely exemplary and is intended to provide further description of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0033] It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the application.

[0034] In the case of no conflict, the embodiments in the application and the features in the embodiments can be combined with each other.

[0035] Example 1 It is an important means in the development stage to evaluate various performances of the cell by specific charging and discharging of the battery. In the laboratory, the battery is usually directly connected to the charging and discharging cabinet, and the battery is charged and discharged by the charging and discharging cabinet to simulate the working of the battery on the whole vehicle. However, this method of evaluating the temperature rise of the battery under the working condition of the battery has great disadvantages: Firstly, when the battery works on the whole vehicle, the battery is connected in series and parallel among multiple cells, and is assembled together through structural members and connecting structural glue. The cells do not have much heat transfer with other surrounding parts, such as Figure 2 As shown in the figure, the heat generated by the battery during work is basically absorbed by the battery body.

[0036] However, the test device built according to the prior art Figure 1 only a part of the heat generated by the battery during work is absorbed by the battery and shown as the temperature rise of the battery, and the other part of the heat (Q1 positive + Q1 negative + Q2 air + Q3 support) is transferred to the outside of the battery through the positive and negative connection harness and the environment convection.

[0037] As shown in the figure, the heat generated by the battery during work is basically absorbed by the battery body. Figure 1As shown, the heat transfer process described above can be expressed by the formula: Qprod = Qabs + (Q1pos + Q1neg + Q2air + Q3holder); ΔT = Qabs / (Cp * mcell).

[0038] Therefore, under the same working conditions, the temperature rise of the battery on the vehicle is different from that of the battery obtained by laboratory test. The temperature rise of the battery in the laboratory test is much smaller than that of the battery actually used on the vehicle, and the temperature of the battery is strongly related to the performance. Only by using the existing test bench in the laboratory to test the temperature rise of the battery cell and then simulate the actual temperature rise of the battery on the vehicle, there is often a large error and no reference.

[0039] Therefore, how to accurately evaluate the performance of the battery in the laboratory test stage has become a problem to be solved. In order to solve the drawbacks of the traditional test bench in testing performance, the embodiment of the present application comprehensively reforms the traditional test bench, and discloses a device for simulating battery pack performance of battery cell based on heat transfer environment migration.

[0040] The embodiment aims to improve the traditional test bench, so that the test bench for battery cell temperature rise experiment in the laboratory can fully simulate the heat transfer mode in the battery pack on the vehicle, and realize the purpose of accurately simulating the temperature rise performance of the battery pack in the actual operation of the vehicle by using the temperature rise condition of the battery cell in the laboratory.

[0041] Specifically, as shown in Figure 3 A device for simulating battery pack performance of battery cell based on heat transfer environment migration, comprising a wrapping structure 5, the wrapping structure 5 is internally provided with a first compartment 6 and at least two second compartments 7 and third compartments 8 adjacent to the first compartment 6, and heat insulation materials 9 are arranged between the first compartment 6 and the second compartment 7 and the third compartment 8; the first compartment 6 is used for placing the measured battery cell 1, and auxiliary battery cells are arranged in the second compartment 7 and the third compartment 8; the measured battery cell and the auxiliary battery cell are both basic units of the measured battery pack, and the measured battery cell and the auxiliary battery cell have the same performance.

[0042] Further, the wrapping structure 5 is externally provided with an air baffle 10, which further blocks the heat transfer between the measured battery cell 1 and the air.

[0043] The wrapping structure 5, the heat insulation material 9 and the air baffle 10 simulate the actual working internal environment of the battery pack, and the measured battery cell and the auxiliary battery cell adjacent thereto simulate the internal heat transfer environment of the battery pack.

[0044] It can be understood that, compared with the test bench of the prior art shown in Figure 1 the embodiment of the present application: By setting the wrapping structure 5, the heat transfer between the battery cell 1 and the air in the prior art test bench test process is blocked; By setting the first compartment 6, the second compartment 7 and the third compartment 8, and setting the auxiliary battery cell 1 in the second compartment 7 and the third compartment 8, and setting the measured battery cell 1 in the first compartment 6, the heat transfer between the internal battery cells 1 in the actual working process of the vehicle battery pack 4 and between the battery cells 1 and the battery pack 4 shell can be simulated. And by abandoning the connection between the positive and negative poles of the battery cell 1 and the busbar through the wire harness, the heat transfer between the battery cell 1 and the connecting wire harness 2 in the prior art test bench test process is blocked.

[0045] Through the above structure, the device for simulating the performance of the battery pack based on the heat transfer environment migration can accurately simulate the working environment of the battery cell 1 in the vehicle battery pack 4, and further provides a theoretical basis for accurately simulating the performance of the battery pack 4 through the performance test of the battery cell 1.

[0046] It can be understood that the wrapping structure 5 forms a semi-closed space wrapping the first compartment 6, the second compartment 7 and the third compartment 8. In this embodiment, the second compartment 7 and the third compartment 8 are arranged on both sides of the first compartment 6. In other embodiments, a compartment unit can also be arranged at the lower part, left side, right side, front side and rear side of the first compartment 6 based on the spatial position of the first compartment 6, for placing the auxiliary battery cell 1.

[0047] The wrapping structure 5 is a semi-closed space with a closed bottom and four sides and an open top. This arrangement can facilitate the placement of the measured battery cell and the auxiliary battery cell. In combination with the arrangement of the air isolation cover 10, the heat transfer in the running environment of the battery pack 4 can also be simulated.

[0048] In this embodiment, the measured battery cell 1 and the auxiliary battery cell are both basic units of the measured battery pack 4, and the performance of the measured battery pack 4 is accurately simulated by testing the performance of the measured battery cell 1. It can be understood that the auxiliary battery cell 1 mentioned in this embodiment refers to other battery cells 1 with the same performance as the measured battery cell 1, which is used to simulate the heat transfer environment of the measured battery cell 1 in the measured battery pack 4. Therefore, by the relative spatial position of the measured battery cell 1 and the auxiliary battery cell 1, the heat transfer environment between the battery cells 1 in the measured battery pack 4 can be fully simulated, and the performance of the battery pack 4 can be accurately simulated.

[0049] It can be understood that the wrapping structure 5 also has a busbar 3 arranged therein, which is used to connect adjacent measured battery cells 1 and auxiliary battery cells 1. Compared with the prior art, the busbar 3 in this embodiment is arranged inside the wrapping structure 5, rather than outside the battery cell 1. In combination with the arrangement of the air isolation cover 10, the heat transfer between the battery cell 1 and the connecting wire harness 2 can be blocked.

[0050] In this embodiment, the wrapping structure 5 is a wooden board or a metal board, and the heat insulating material 9 is foam or aerogel. In other embodiments, other materials may also be used.

[0051] Working process: Test bench for cell level simulation test pack performance such as Figure 3 As shown, the cell 2 under test is placed between two auxiliary cells, cell 1 and cell 3, and the cells 1 are connected by a busbar. The purpose of this construction is to simulate the heat dissipation environment of the cell 1 inside the pack as much as possible. The cells 1 are filled with insulation material 9, which can be foam or aerogel. The small module is wrapped with structural parts to simulate the crossbeams and module end plates inside the battery pack. The materials can be wood, aluminum, etc. In addition, a wind shield 10 is added to the outside of the entire test sample to isolate the sample from heat exchange caused by the airflow inside the test environment chamber.

[0052] Example 2 This embodiment discloses a method for simulating battery pack performance based on the migration of heat transfer environment of battery cells.

[0053] A method for simulating battery pack performance based on heat transfer environment migration of a cell, comprising the following steps: Obtain temperature rise data of a No. 1 battery cell constituting the No. 1 battery pack during the charge and discharge process of the No. 1 battery pack, select the temperature rise curves of the highest temperature battery cell and the lowest temperature battery cell, and calibrate them as a first temperature rise curve and a second temperature rise curve, respectively; Placing the No. 1 battery cell into the first compartment of the device for simulating battery pack performance based on thermal environment migration as described in any one of claims 1 to 6; The thickness and thermal conductivity of the wrapped structural member and the thickness and thermal conductivity of the insulation material are combined as parameters; Adjust the parameter combination so that under the same current operating condition, the temperature distribution of the first battery cell in the first compartment is close to the first temperature rise curve, thereby obtaining a first parameter combination; similarly, adjust the temperature distribution of the first battery cell in the first compartment so that it is close to the second temperature rise curve, thereby obtaining a second parameter combination; Place the No. 2 battery cell that makes up the No. 2 battery pack into the first compartment. Under the same current conditions, apply the first parameter combination and the second parameter combination respectively. The measured maximum temperature and minimum temperature of the No. 2 battery cell are the simulated temperatures of the highest temperature cell and the lowest temperature cell of the No. 2 battery pack.

[0054] The method described in this embodiment adopts a migration or analogy idea as a whole, considers that the heat transfer modes of the battery packs with the same or similar structures are similar, and the energy transfer modes and total amounts of heat transfer between the battery packs and the cells are the same. Thus, the temperature rise data of the cells in a battery pack with known performance are used to calibrate the environmental factors in the battery pack, and it is considered that the calibration results are also applicable to the battery pack with unknown performance. Then, when studying any battery pack with unknown performance, there is no need to actually build a real battery pack with unknown performance, and only based on the calibration results, the calibration results (i.e. the environmental factors in the battery pack) are applied to the cell units of the battery pack with unknown performance, and the performance of the cell units constituting the battery pack with unknown performance is tested, so that the overall performance of the battery pack with unknown performance can be reasonably speculated and simulated.

[0055] The known performance battery pack is a first battery pack, and the unknown performance battery pack is a second battery pack.

[0056] The environmental factors are related to the structure in the battery pack. Based on the device for simulating the performance of the battery pack by migrating the heat transfer environment in the first embodiment, the environmental factors considered in this embodiment are mainly located on the thickness and thermal conductivity of the wrapping structure and the thickness and thermal conductivity of the thermal insulation material.

[0057] It can be understood that, in order to more accurately simulate, the structure of the second battery pack and the first battery pack is the same or similar in this embodiment.

[0058] Further, the temperature rise data of the cells in the first battery pack during the cyclic charging and discharging process are obtained, and specifically include: The periodic pulse current is applied to the first battery pack to make the first battery pack perform cyclic charging and discharging, and the charging and discharging amounts are equal, and the temperature rise data of the first cell during the process are measured. When the temperature change rate of the first cell is less than a set value, it is considered that the system reaches an equilibrium state, and the charging and discharging cycle is stopped.

[0059] Further, the first parameter combination and the second parameter combination are applied respectively, and specifically include: The thickness and thermal conductivity of the wrapping structure and the thickness and thermal conductivity of the thermal insulation material are set according to the first parameter combination and the second parameter combination respectively.

[0060] In order to better describe the technical scheme of this embodiment, the following will be explained and described in combination with the drawings. In the following description, in order to facilitate the description, the first battery pack and the second battery pack are marked as Pack A and pack B respectively. The cells in Pack A are called cell A, and the cells in pack B are called cell B.

[0061] Pack A and pack B are similar in structure, as shown in Figure 4 Both are CTP structures, and the battery cells are directly bonded to the bottom plate with structural members, and the series connection between the battery cells is realized by busbar connection. As shown in Figure 5 , the highest temperature cell and the lowest temperature cell in pack A are located at the geometric center of the pack, and the highest temperature generally appears at the geometric center of the pack because the heat exchange of the peripheral components is difficult, and the lowest temperature generally appears at the edge of the pack because the heat exchange with the peripheral components is easier.

[0062] As shown in Figure 6 , the battery pack pack A with existing test data is selected, and the test conditions of pack A are as follows: The ambient temperature is 25°C, the initial SOC of the pack is 50%, and the periodic pulse current condition is applied to the pack, specifically, the charging rate is 5C for 10s, and the discharging rate is 5C for 10s, as shown in Figure 7 , so the cycle, the charge and discharge capacity is equal, which ensures that the SOC of the pack fluctuates in a small range during the test, avoiding the situation that the test temperature is not controlled due to the change of SOC.

[0063] The final test results of pack A are shown in Figure 8 , under the periodic pulse condition, the heat generation of the battery and the heat exchange of the surrounding system reach a balance, and the temperature finally balances to a specific temperature. In the experiment, when the temperature change rate of the battery cell is less than 0.5℃ / 30min, it is considered that the system reaches a balanced state. The temperature rise data and temperature rise curve of the two battery cells with the highest temperature and the lowest temperature in pack A are selected (i.e. the first temperature rise curve and the second temperature rise curve).

[0064] The temperatures of the highest temperature cell and the lowest temperature cell measured in the above test conditions of pack A are the calibration objects, and the cell A battery cell level calibration test bench is built according to the embodiment one Figure 3 , as shown. In this embodiment, the thermal insulation material is selected as foam, and the wrapping structure is selected as wood board. The thickness and thermal conductivity of foam and wood board are used as parameter combinations. Adjust the parameter combinations until the temperature rise curve of cell A in the device shown in Figure 3 of embodiment one is infinitely close to the temperature rise curves of the two battery cells with the highest temperature and the lowest temperature in pack A, and then two sets of parameter combinations are obtained, i.e. the first parameter combination and the second parameter combination.

[0065] The final calibrated parameters are shown in Table 1: Table 1 Cell A calibration parameters of pack A

[0066] So far, we have obtained the parameter combination of the heat insulation material and the wrapping structure component of the test bench in the two cases of the highest temperature and the lowest temperature of the cells in pack A. Applying this parameter combination to cell B, we can predict the temperature of the highest temperature and the lowest temperature of the cells in pack B, thereby completing the performance prediction of pack B based on the test data performance of cell B.

[0067] The embodiment applies the idea of migration and analogy to the unknown performance battery pack and the known performance battery pack with the same or similar structure, takes the temperature rise curves of the highest temperature cell and the lowest temperature cell in the known performance battery pack as the calibration object, calibrates the parameter combination of the cell and the heat transfer device based on the calibration object and the known performance battery pack, and applies the calibrated parameter combination to the cells of the unknown performance battery pack, so as to simulate the performance of the unknown performance battery pack and predict the temperature of the highest temperature cell and the lowest temperature cell of the unknown performance battery pack without actual measurement and the problem of reference difference caused by the difference between the laboratory environment and the battery pack environment.

[0068] The above describes the specific embodiments of the present application in combination with the drawings, but is not a limitation on the protection scope of the present application. Those skilled in the art should understand that various modifications or changes made by those skilled in the art on the basis of the technical solutions of the present application without creative labor are still within the protection scope of the present application.

Claims

1. A device for simulating battery pack performance based on thermal environment migration, characterized in that: It includes a wrapping structure, wherein a first compartment and at least two second compartments and a third compartment adjacent to the first compartment are arranged inside the wrapping structure, and heat insulation materials are arranged between the first compartment and the second compartment and the third compartment; the first compartment is used to place the battery cell under test, and auxiliary batteries are arranged in the second compartment and the third compartment; the battery cell under test and the auxiliary batteries are both basic units that constitute the battery pack under test.

2. The device for simulating battery pack performance based on thermal environment migration of a battery cell according to claim 1, characterized in that: A wind shield is provided on the outside of the wrapping structure.

3. The device for simulating battery pack performance based on thermal environment migration of a battery cell according to claim 1, characterized in that: The wrapping structure is a wooden board or a metal board.

4. The device for simulating battery pack performance based on thermal environment migration of a battery cell according to claim 1, characterized in that: The thermal insulation material is foam or aerogel.

5. The device for simulating battery pack performance based on thermal environment migration of a battery cell according to claim 1, characterized in that: A busbar is also provided in the wrapping structure, and the busbar is used to connect adjacent tested cells and auxiliary cells.

6. The device for simulating battery pack performance based on thermal environment migration of a battery cell according to claim 1, characterized in that: The wrapping structure is a semi-closed structure with an open top, and the tops of the first compartment, the second compartment and the third compartment are open.

7. A method for simulating battery pack performance based on thermal environment migration, characterized in that: The following steps are involved: Obtain temperature rise data of a No. 1 battery cell constituting the No. 1 battery pack during the charge and discharge process of the No. 1 battery pack, select the temperature rise curves of the highest temperature battery cell and the lowest temperature battery cell, and calibrate them as a first temperature rise curve and a second temperature rise curve, respectively; Placing the No. 1 battery cell into the first compartment of the device for simulating battery pack performance based on thermal environment migration as described in any one of claims 1 to 6; The thickness and thermal conductivity of the wrapped structural member and the thickness and thermal conductivity of the insulation material are combined as parameters; Adjusting the parameter combination so that, under the same current operating condition, the temperature distribution of the first battery cell in the first compartment is close to the first temperature rise curve, thereby obtaining a first parameter combination; Similarly, the temperature distribution of the first cell in the first compartment is made close to the second temperature rise curve to obtain the second parameter combination; Place the No. 2 battery cell that makes up the No. 2 battery pack into the first compartment. Under the same current conditions, apply the first parameter combination and the second parameter combination respectively. The measured maximum temperature and minimum temperature of the No. 2 battery cell are the simulated temperatures of the highest temperature cell and the lowest temperature cell of the No. 2 battery pack.

8. The method for simulating battery pack performance based on heat transfer environment migration of a battery cell according to claim 7, characterized in that: The structure of the No. 2 battery pack is the same as that of the No. 1 battery pack.

9. The method for simulating battery pack performance based on heat transfer environment migration according to claim 7, characterized in that: Obtain the cell temperature rise data during the charge and discharge cycle of the No. 1 battery pack, including: Apply a periodic pulse current to the D1 battery pack to cycle charge and discharge, with equal charge and discharge amounts, and measure the temperature rise of the D1 battery cell during this process. When the temperature change rate of cell 1 is observed to be less than the set value, the system is considered to have reached a state of equilibrium and the charge and discharge cycle is stopped.

10. The method for simulating battery pack performance based on heat transfer environment migration of a battery cell according to claim 7, characterized in that: The first parameter combination and the second parameter combination are applied respectively, specifically: The thickness and thermal conductivity of the wrapping structure, and the thickness and thermal conductivity of the thermal insulation material are set according to the first parameter combination and the second parameter combination, respectively.

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