Power battery thermal disaster prevention and control system and method based on multi-level active and passive combination

Abstract

The invention discloses a multi-level active and passive combination-based power battery thermal disaster prevention and control system and method, and relates to the technical field of battery thermal disaster prevention and control, and the system comprises at least two first heat conduction structures, at least two second heat conduction structures, at least two heat insulation structures and at least one liquid cooling structure, the first heat conduction structure and the second heat conduction structure form a space for placing a battery cell, the space among the first heat conduction structure, the second heat conduction structure and the battery cell is filled with a phase change material to form a phase change structure, and a battery module is placed between the adjacent heat insulation structures; the heat insulation structure is located on the outer side of the phase change structure, the second heat conduction structure can stretch into a liquid cooling channel of the liquid cooling structure, and the liquid cooling channel is used for being filled with a cooling working medium. According to the invention, multi-level thermal safety protection can be provided for the battery module, and the contradiction between efficient heat dissipation under conventional working conditions and thermal runaway spreading directional heat insulation is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery thermal disaster prevention and control, in particular to a power battery thermal disaster prevention and control system and method based on multi-level active and passive combination. BACKGROUND

[0002] As the core carrier of intelligentization and electrification in the transportation field, the power battery module of the electric vehicle is iterating and upgrading towards high energy density and high safety. With the large-scale application of high-nickel ternary battery system and super-fast charging technology, the service life and consistency of the battery cell are required to be higher while improving the vehicle's range. Under this background, the large-size battery module not only needs to withstand the performance aging test of thousands of deep charge and discharge cycles in the life cycle, but also needs to prevent the risk of thermal runaway caused by lithium dendrite puncture and local overheating under fast charging and harsh working conditions, which will pose a double challenge to the thermal safety protection of the module system level.

[0003] The essence of power battery thermal runaway is a chain reaction of electrochemical-thermal-mechanical multi-field coupling: the Joule heat generated by local internal short circuit triggers the decomposition of SEI film, the oxygen release of the positive electrode and the vaporization of the electrolyte form a combustible gas, and finally a high-temperature jet flame and a three-dimensional heat spread at the module level are formed. More seriously, when the temperature of the single battery cell exceeds 120-150 ℃, a large amount of heat generated by irreversible reaction will quickly spread to adjacent battery cells, and then form a thermal runaway spread with a "domino effect", thereby inducing serious thermal runaway accidents, such as explosion and combustion. Therefore, using safe and reliable technology to effectively block the thermal runaway propagation path will be a feasible path to inhibit the spread of thermal runaway.

[0004] Liquid cooling technology has become the preferred thermal management solution for vehicle manufacturers due to its efficient and reliable temperature control performance. However, the current mainstream liquid cooling system has significant performance defects. On the one hand, in order to improve the intrinsic heat dissipation efficiency of the liquid cooling system, most studies tend to design too many unreasonable heat transfer paths, which will accelerate the heat propagation during the thermal runaway stage. On the other hand, the application of passive thermal barrier components can block the heat spread, but their independent design cannot be linked with the liquid cooling components, and even worsen the heat dissipation channel under normal operation. Therefore, how to balance the efficient heat dissipation under normal working conditions and the directional heat insulation under thermal runaway triggering, break through the existing technical bottlenecks, and improve the thermal safety protection level under extreme conditions while ensuring the temperature control performance of the system, will be a technical problem that needs to be solved urgently. SUMMARY

[0005] The purpose of the present application is to provide a power battery thermal disaster prevention and control system and method based on multi-level active and passive combination to solve the problems existing in the prior art, which can provide multi-level thermal safety protection for the battery module and solve the contradiction between efficient heat dissipation under normal working conditions and directional heat insulation under thermal runaway spread.

[0006] To achieve the above object, the present application provides the following scheme: The present application provides a power battery thermal disaster prevention and control system based on multi-level active and passive combination, comprising: at least two first heat-conducting structures, at least two second heat-conducting structures, at least two heat-insulating structures, and at least one liquid cooling structure, the first heat-conducting structures and the second heat-conducting structures form a space for placing battery cells, the space between the first heat-conducting structures, the second heat-conducting structures, and the battery cells is used to fill phase change materials to form a phase change structure, the heat-insulating structures are located outside the phase change structure, the second heat-conducting structures can extend into the liquid cooling channel of the liquid cooling structure, and the liquid cooling channel is used to fill cooling working medium.

[0007] In some specific schemes, in the battery module, the first heat-conducting structures are arranged in parallel, the first heat-conducting structures are used to arrange battery cells between adjacent first heat-conducting structures, the second heat-conducting structures are arranged in parallel, the second heat-conducting structures are used to arrange battery modules between adjacent second heat-conducting structures, and the first heat-conducting structures are arranged perpendicularly to the second heat-conducting structures.

[0008] In some specific schemes, the first heat-conducting structure is a plate-shaped structure, one side of the first heat-conducting structure is provided with a first notch, the other side of the first heat-conducting structure is provided with a second notch, the first notch and the second notch are arranged in a staggered manner, and the first notch and the second notch are used to arrange the second heat-conducting structures.

[0009] In some specific schemes, in the battery module, two second heat-conducting structures are arranged in a staggered and parallel manner.

[0010] In some specific schemes, in the battery module, the second heat-conducting structures are arranged in a staggered and parallel manner.

[0011] In some specific schemes, the second heat-conducting structure has a larger thermal conductivity than the first heat-conducting structure.

[0012] In some specific schemes, the second heat-conducting structure is a heat pipe.

[0013] In some specific schemes, the heat-insulating structure is a heat-insulating layer prepared from a heat-insulating material, and the heat-insulating structures are arranged in parallel.

[0014] In some specific schemes, the liquid cooling structure is located at one end of the battery module, and one end of the second heat-conducting structure protrudes from the first heat-conducting structure of the end of the battery module and can extend into the liquid cooling channel.

[0015] The application provides a prevention and control method of the power battery thermal disaster prevention and control system based on the multi-level active and passive combination. In the thermal management mode, the heat generated in the charging and discharging process of the battery cell is stored in the phase change structure, thereby providing excellent temperature control performance for the battery module; the phase change structure transmits the stored heat to the liquid cooling structure through the first heat conduction structure and the second heat conduction structure, exchanges heat, and realizes passive heat dissipation. In the thermal runaway mode, the heat generated by the battery cell triggering thermal runaway is greater than that generated by the battery cell in the thermal management mode; the phase change structure transmits the stored heat to the liquid cooling structure through the first heat conduction structure and the second heat conduction structure, adjusts the flow rate of the cooling medium in the cooling channel of the liquid cooling structure, and realizes active heat dissipation.

[0016] The application has the following technical effects compared with the prior art: In the application, the phase change structure absorbs the heat generated by the battery, and the heat absorbed by the phase change structure is transmitted to the liquid cooling structure through the heat transfer path formed by the first heat conduction structure and the second heat conduction structure, and then is cooled, thereby realizing passive cooling; the flow rate of the cooling medium in the liquid cooling structure can be changed to realize active cooling; the heat insulation structure avoids the spread of thermal runaway, thereby realizing passive inhibition; while the heat insulation structure avoids the spread of thermal runaway, the flow rate of the cooling medium in the liquid cooling structure can be changed to realize active inhibition. The application constructs a multi-level active and passive combination of passive cooling-active cooling-passive inhibition-active inhibition heat safety strategy, reasonably strengthens heat transport and cuts off the key heat transfer path of the spread of thermal runaway, and can effectively solve the contradiction between heat dissipation under the normal operating condition of the large-size power battery module and heat insulation after the triggering of thermal runaway, and significantly improve the thermal safety protection level of the battery module. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed in the embodiments. Obviously, the drawings in the following description only constitute some embodiments of the application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0018] Figure 1 The application provides a prevention and control method of the power battery thermal disaster prevention and control system based on the multi-level active and passive combination. Figure 2 The application provides a prevention and control method of the power battery thermal disaster prevention and control system based on the multi-level active and passive combination. Figure 1 Figure 3 The application provides a prevention and control method of the power battery thermal disaster prevention and control system based on the multi-level active and passive combination. Figure 2 The application provides a prevention and control method of the power battery thermal disaster prevention and control system based on the multi-level active and passive combination.​Figure 4 Application diagram for composite phase change material module in some embodiments of the present application; Figure 5 Application diagram for composite phase change material module in some embodiments of the present application (remove phase change structure); Figure 6 Schematic diagram of the first heat conduction structure in some embodiments of the present application; Figure 7 Schematic diagram of the second heat conduction structure in some embodiments of the present application; Figure 8 Schematic diagram of the working process of the power battery thermal disaster prevention and control system based on multi-level active and passive combination in some embodiments of the present application; Figure 9 Temperature rise curve of each single cell in the battery module under severe operating conditions; Figure 10 Temperature rise curve of No. 7, No. 8 and No. 9 cells during thermal runaway process under local overheating condition of No. 9 cell; Figure 11 Temperature rise curve of the remaining cells during thermal runaway process under local overheating condition of No. 9 cell; Figure 12 Temperature rise curve of No. 7, No. 8 and No. 9 cells during thermal runaway process under needle puncture condition of No. 9 cell; Figure 13 Temperature rise curve of the remaining cells during thermal runaway process under needle puncture condition of No. 9 cell; Figure 14 Temperature rise curve of No. 7, No. 8 and No. 9 cells during thermal runaway process under local overheating and needle puncture condition of No. 9 cell; Figure 15 Temperature rise curve of the remaining cells during thermal runaway process under local overheating and needle puncture condition of No. 9 cell; Figure 16 Temperature curve of No. 9 cell under different flow rates; Figure 17 Temperature curve of No. 7 cell under different flow rates; Figure 18 Temperature curve of No. 8 cell under different flow rates; Figure 19 Bar chart of the number of cells induced by local overheating and needle puncture to cause thermal runaway; In the figure: 1-first heat conduction structure, 2-second heat conduction structure, 3-thermal insulation structure, 4-phase change structure, 5-liquid cooling structure, 6-first notch, 7-second notch, 8-cell, 9-inlet, 10-outlet, 11-connection row piece. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0020] The purpose of the present application is to provide a multi-level active and passive combined power battery thermal disaster prevention and control system and method to solve the problems existing in the prior art, which can provide multi-level thermal safety protection for the battery module and solve the contradiction between efficient heat dissipation under normal working conditions and directional heat insulation of thermal runaway spread.

[0021] In order to make the above-mentioned purposes, features and advantages of the present application more apparent and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0022] Embodiment one As Figures 1 to 8As shown, the embodiment provides a multi-level active and passive combined power battery thermal disaster prevention and control system applied to a power battery. The battery module of the power battery includes a plurality of battery modules. Adjacent battery modules are connected through a connecting row piece 11. Each battery module includes a plurality of battery cells 8. The embodiment is applicable to cylindrical battery modules of different electrochemical systems and sizes, for example, a battery module of model NCM811-26650. The multi-level active and passive combined power battery thermal disaster prevention and control system of the embodiment includes at least two first heat conduction structures 1, at least two second heat conduction structures 2, at least two heat insulation structures 3, and at least one liquid cooling structure 5. The first heat conduction structure 1 and the second heat conduction structure 2 form a space for placing the battery cell 8. The space between the first heat conduction structure 1, the second heat conduction structure 2, and the battery cell 8 is used to fill a phase change material to form a phase change structure 4. Adjacent heat insulation structures 3 are used to place battery modules. The heat insulation structure 3 is located outside the phase change structure 4. The second heat conduction structure 2 can extend into the liquid cooling channel of the liquid cooling structure 5. The liquid cooling channel is used to fill a cooling working medium. In the embodiment, the phase change structure 4 absorbs the heat generated by the battery. The heat absorbed by the phase change structure 4 is transferred to the liquid cooling structure 5 through the heat transfer path formed by the first heat conduction structure 1 and the second heat conduction structure 2 to achieve passive cooling. Changing the flow rate of the cooling working medium in the liquid cooling structure 5 can achieve active cooling. The heat insulation structure 3 prevents the spread of thermal runaway to achieve passive inhibition. While the heat insulation structure 3 prevents the spread of thermal runaway, changing the flow rate of the cooling working medium in the liquid cooling structure 5 can achieve active inhibition. The embodiment constructs a multi-level active and passive combined thermal safety strategy of passive cooling-active cooling-passive inhibition-active inhibition. The heat transfer is scientifically and reasonably strengthened, and the key heat transfer path of thermal runaway spread is cut off. The heat dissipation under the normal operating condition of the large-size power battery module and the heat insulation after the triggering of thermal runaway can be effectively solved. The thermal safety protection level of the battery module is significantly improved.

[0023] In the detailed description of some embodiments, the first heat conduction structure 1, the second heat conduction structure 2, and the phase change structure 4 form a modularized composite phase change material module to form a modular structure.

[0024] In the detailed description of some embodiments, the phase change material is preferably a composite phase change material.

[0025] In the detailed description of some embodiments, in the battery module, each first heat conduction structure 1 is arranged in parallel. Adjacent first heat conduction structures 1 are used to arrange battery cells 8. Each second heat conduction structure 2 is arranged in parallel. Adjacent second heat conduction structures 2 are used to arrange battery modules. The first heat conduction structure 1 and the second heat conduction structure 2 are arranged perpendicularly.

[0026] In some specific embodiments, the first heat-conducting structure 1 is a plate-like structure. A first notch 6 is provided on one side of the first heat-conducting structure 1, and a second notch 7 is provided on the other side. The first notch 6 and the second notch 7 are staggered, i.e., asymmetrically arranged. Both the first notch 6 and the second notch 7 are used to house the second heat-conducting structure 2. In this embodiment, after the first heat-conducting structure 1 has the first notch 6 and the second notch 7, the protruding portions on both sides of the first heat-conducting structure 1 can be embedded inside the phase change structure 4, forming a heat transfer path and transferring the heat generated by the cell 8 to the phase change material more quickly. Furthermore, the second heat-conducting structure 2 is located at the first notch 6 and the second notch 7, enabling the second heat-conducting structure 2 to provide a more uniform temperature distribution for the battery.

[0027] In some specific embodiments, in a battery module, two second heat-conducting structures 2 are staggered and arranged in parallel; in a battery module, each second heat-conducting structure 2 is staggered and arranged in parallel. The staggered arrangement of the second heat-conducting structures 2 allows different second heat-conducting structures 2 on multiple battery modules to form a structure with varying heights after the second heat-conducting structures 2 are inserted into the liquid cooling structure 5, thereby enhancing the flow state of the cooling medium in the cooling channel and optimizing heat transfer efficiency.

[0028] In some specific embodiments, the thermal conductivity of the second heat-conducting structure 2 is greater than that of the first heat-conducting structure 1; the second heat-conducting structure 2 is a heat pipe; the first heat-conducting structure 1 is a heat-conducting plate, preferably an aluminum plate or a copper plate, and the material of the first heat-conducting structure 1 can be selected according to requirements.

[0029] In some specific embodiments, each heat insulation structure 3 is arranged in parallel. The heat insulation structure 3 is a heat insulation layer made of heat insulation material. The heat insulation material is preferably aerogel, and the material of the heat insulation layer can be selected according to the requirements.

[0030] In some specific embodiments, the liquid cooling structure 5 is located at one end of the battery module, and there is a gap between the liquid cooling structure 5 and the first heat-conducting structure 1 at one end of the battery module. One end of the second heat-conducting structure 2 protrudes from the first heat-conducting structure 1 at the end of the battery module and can extend into the liquid cooling channel. The liquid cooling structure 5 is provided with an inlet 9 and an outlet 10 for the passage of the cooling working fluid.

[0031] The fabrication process of the multi-layered active-passive combined power battery thermal disaster prevention and control system in this embodiment when applied to a battery module is as follows: First, a first thermal conductive structure 1 is set at the front and back of each cell 8, with the first notch 6 of each first thermal conductive structure 1 located on the same side and the second notch 7 of each first thermal conductive structure 1 located on the same side; then, a second thermal conductive structure 2 is inserted into each first notch 6 and another second thermal conductive structure 2 is inserted into each second notch 7; then, phase change material is encapsulated in the space between the cell 8, the first thermal conductive structure 1 and the second thermal conductive structure 2 to form a phase change structure 4; finally, thermal insulation structures 3 are set on both sides of the battery module, and a thermal insulation structure 3 is set between two adjacent battery modules to assemble them into a battery module.

[0032] Taking each battery module as an example, which includes three cells 8, and each battery module as an example, there are a total of twelve cells 8.

[0033] Simulations are performed using this embodiment, such as... Figure 9 As shown in the figure, different curves represent different temperature curves of cell 8. For example, C1 corresponds to the temperature curve of cell 1. The simulation results show that even under harsh conditions with an ambient temperature of 40 ℃ and a discharge rate of 3 C, the maximum temperature of the battery module can still be controlled within 50 ℃, and the maximum temperature difference is 3.4 ℃, which is sufficient to prove that the system constructed in this embodiment has efficient temperature control performance.

[0034] Simulations are performed using this embodiment, such as... Figures 10 to 15 As shown in the figure, different curves represent different temperature curves of cell 8. For example, C1 corresponds to the temperature curve of cell 1. Figure 10 and Figure 11 The simulation conditions were based on localized overheating of cell number 9 in the battery module. Figure 10 Temperature profiles for cells 7, 8, and 9 of the battery module. Figure 11 Temperature profiles for the remaining cells 8 of the battery module; Figure 12 and Figure 13 The simulation conditions involved puncturing cell number 9 in the battery module. Figure 12 Temperature profiles for cells 7, 8, and 9 of the battery module. Figure 13 Temperature profiles for the remaining cells 8 of the battery module; Figure 14 and Figure 15 The simulation conditions were based on localized overheating and needle puncture in cell No. 9 of the battery module. Figure 14 Temperature profiles for cells 7, 8, and 9 of the battery module. Figure 15The temperature curves of the remaining cells 8 in the battery module are shown. The simulation results show that even when thermal runaway is triggered under multiple abuse conditions, thanks to the multi-level active and passive power battery thermal disaster prevention and control system constructed in this embodiment, the spread of thermal runaway in the battery module is effectively suppressed, and the propagation of thermal runaway between modules is avoided.

[0035] Simulations are performed using this embodiment, such as... Figures 16 to 18 As shown in the figure, different curves represent different temperature curves of cell 8. For example, C1 corresponds to the temperature curve of cell 1. Figures 16 to 18 Performance of the battery module in suppressing thermal runaway at different flow rates: Figure 16 The temperature profiles of cell No. 9 at different flow rates are shown. Figure 17 Temperature curves of cell No. 7 at different flow rates; Figure 18 Temperature curves of cell No. 8 at different flow rates; Figure 19 The number of cells 8 affected by thermal runaway induced by localized overheating and needle puncture is represented by the horizontal axis, which represents the cooling fluid flow rate at the inlet 9 of the liquid cooling structure 5, and the vertical axis represents the number of cells experiencing thermal runaway. Simulation results show that by appropriately adjusting the inlet 9 velocity of the liquid cooling channel, thermal runaway can be suppressed at the individual cell level, demonstrating excellent thermal disaster prevention and control capabilities.

[0036] This embodiment is based on a modularly assembleable composite phase change material module coupled with a liquid cooling structure 5, formed by a first thermally conductive structure 1, a second thermally conductive structure 2, and a phase change structure 4. Utilizing the high latent heat of the phase change material and the efficient heat dissipation of the liquid cooling structure 5, the performance of the hybrid battery thermal management system is significantly improved. Furthermore, the modular assembly approach makes the system highly flexible, allowing for modification and design based on the actual size and scale of the battery module, expanding its practical application scenarios. The addition of the first thermally conductive structure 1 and the second thermally conductive structure 2 creates a horizontally and vertically distributed enhanced heat transfer path within the composite phase change material module, effectively improving the heat transport efficiency of the battery module in different operating modes. Based on the aforementioned battery thermal management system, a thermal insulation structure 3 is assembled, proposing a passive-active cooling-passive suppression-active suppression battery thermal runaway suppression strategy. This constructs a multi-layered active-passive combined power battery thermal disaster prevention and control system, providing all-weather thermal safety protection for the battery module.

[0037] The modular assembly design of this embodiment enables the constructed thermal management system to have high assembly flexibility and compatibility. The proposed thermal runaway suppression strategy based on passive cooling-active cooling-passive suppression-active suppression can provide multi-level thermal safety protection for battery modules and resolve the contradiction between efficient heat dissipation under normal operating conditions and directional thermal insulation for thermal runaway propagation. Based on the multi-level active and passive battery thermal disaster prevention and control system, after appropriately adjusting the cooling fluid flow rate, battery thermal runaway can be suppressed at the single cell level, demonstrating excellent thermal disaster prevention and control capabilities.

[0038] Example 2 This embodiment provides a prevention and control method for thermal disaster prevention and control of power batteries based on a multi-level active and passive combined system as described in Embodiment 1, including: In the conventional thermal management mode, the heat generated during the charging and discharging process of the battery cell 8 is stored by the phase change structure 4 using its high latent heat, providing excellent temperature control performance for the battery module. Subsequently, the phase change structure 4 transfers the heat stored in the phase change structure 4 to the cooling working medium of the liquid cooling channel of the liquid cooling structure 5 through the enhanced heat transfer path constructed by the first heat conduction structure 1 and the second heat conduction structure 2, thereby carrying out rapid heat exchange and achieving passive heat dissipation. In thermal runaway mode, the heat generated by the cell 8 that triggers thermal runaway is greater than the heat generated by the cell 8 in thermal management mode, and it quickly spreads to the entire battery module. The composite phase change material module and the liquid cooling structure 5 work simultaneously to dissipate heat from the cell 8. The phase change structure 4 transfers the heat stored in the phase change structure 4 to the liquid cooling structure 5 through the horizontal and vertical heat transfer paths constructed by the first heat conduction structure 1 and the second heat conduction structure 2, thereby improving the heat transport efficiency of the battery module that has experienced thermal runaway and rapidly reducing the temperature of the thermal runaway cell 8. The heat insulation structure 3 pre-assembled between the composite phase change material modules will cut off the heat transfer path of thermal runaway in time, effectively blocking the spread of heat and firmly locking the thermal runaway inside a single battery module. On this basis, increasing the flow rate of the cooling medium in the cooling channel of the liquid cooling structure 5 can further suppress the thermal runaway at the single cell level and achieve active heat dissipation.

[0039] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A multi-level active and passive combined thermal disaster prevention and control system for power batteries, characterized in that: include: The device includes at least two first thermally conductive structures, at least two second thermally conductive structures, at least two thermal insulation structures, and at least one liquid cooling structure. The first and second thermally conductive structures form a space for placing a battery cell. The space between the first and second thermally conductive structures and the battery cell is used to fill a phase change material to form a phase change structure. The adjacent thermal insulation structures are used to place a battery module. The thermal insulation structures are located outside the phase change structure. The second thermally conductive structures can extend into the liquid cooling channel of the liquid cooling structure. The liquid cooling channel is used to fill a cooling medium.

2. The power battery thermal disaster prevention and control system based on multi-level active and passive combination as described in claim 1, characterized in that: In the battery module, each of the first heat-conducting structures is arranged in parallel, and the space between adjacent first heat-conducting structures is used to arrange battery cells. Each of the second heat-conducting structures is arranged in parallel, and the space between adjacent second heat-conducting structures is used to arrange battery modules. The first heat-conducting structures and the second heat-conducting structures are arranged perpendicularly.

3. The power battery thermal disaster prevention and control system based on multi-level active and passive combination as described in claim 1, characterized in that: The first heat-conducting structure is a plate-shaped structure. A first notch is provided on one side of the first heat-conducting structure, and a second notch is provided on the other side of the first heat-conducting structure. The first notch and the second notch are staggered and are both used to set the second heat-conducting structure.

4. The power battery thermal disaster prevention and control system based on multi-level active and passive combination as described in claim 3, characterized in that: In the battery module, the two second heat-conducting structures are staggered and arranged in parallel.

5. The power battery thermal disaster prevention and control system based on multi-level active and passive combination as described in claim 3, characterized in that: In the battery module, each of the second heat-conducting structures is staggered and arranged in parallel.

6. The power battery thermal disaster prevention and control system based on multi-level active and passive combination as described in claim 1, characterized in that: The thermal conductivity of the second thermally conductive structure is greater than that of the first thermally conductive structure.

7. The power battery thermal disaster prevention and control system based on multi-level active and passive combination as described in claim 1, characterized in that: The second heat-conducting structure is a heat pipe.

8. The power battery thermal disaster prevention and control system based on multi-level active and passive combination as described in claim 1, characterized in that: The heat insulation structure is a heat insulation layer made of heat insulation material, and the heat insulation structures are arranged in parallel.

9. The power battery thermal disaster prevention and control system based on multi-level active and passive combination as described in claim 1, characterized in that: The liquid cooling structure is located at one end of the battery module, and one end of the second heat-conducting structure protrudes from the first heat-conducting structure at the end of the battery module and can extend into the liquid cooling channel.

10. A method for preventing and controlling thermal disasters in power batteries using a multi-level active-passive combined system as described in any one of claims 1-9, characterized in that: include: In thermal management mode, the heat generated during the charging and discharging process of the battery cell is stored by the phase change structure, providing excellent temperature control performance for the battery module. The phase change structure transfers the stored heat to the liquid cooling structure through the first thermal conduction structure and the second thermal conduction structure for heat exchange, thereby achieving passive heat dissipation. In thermal runaway mode, the heat generated by the cell that triggers thermal runaway is greater than the heat generated by the cell in thermal management mode. The phase change structure transfers the stored heat to the liquid cooling structure through the first and second thermal conductive structures, thereby adjusting the flow rate of the cooling medium in the cooling channel of the liquid cooling structure to achieve active heat dissipation.

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