Power battery thermal management system

Abstract

The invention relates to a power battery thermal management system, which comprises: an aluminum shell battery module, the aluminum shell battery module is provided with a plurality of battery cells and a plurality of cooling and buffering integrated units, and the cooling and buffering integrated units and the battery cells are alternately stacked; the cooling and buffering integrated unit comprises a heat-conducting substrate and a phase-change material composite layer, the heat-conducting substrate and the phase-change material composite layer are arranged on two sides of the cooling and buffering integrated unit, and the heat-conducting substrate and the phase-change material composite layer are respectively attached and contacted with the battery cell; a heat pipe is embedded in the heat conduction substrate, and the heat pipe is connected with a condensation section located outside the heat conduction substrate. By introducing a cooperative mechanism of passive heat absorption and active dredging, efficient, uniform and reliable heat management of the power battery can be realized, so that the fast charging performance, the cycle life and the intrinsic safety level of the battery are greatly improved.

Description

Technical Field

[0001] This application relates to the field of battery thermal management technology, and more specifically, to a power battery thermal management system. Background Technology

[0002] Currently, liquid-cooled plate-based thermal management systems for power batteries are widely used in electric vehicles, energy storage systems, and other fields. While these systems possess basic heat dissipation capabilities, they still face several technical challenges and limitations in addressing high-power fast charging, improving battery cycle life, and ensuring safety. The main problems with existing technologies in power battery thermal management are as follows: First, most mainstream liquid cooling systems use bottom cooling, which results in a long heat dissipation path, high thermal resistance, and a bottleneck in cooling efficiency. The heat generated by the battery must pass through multiple layers of media, including the cell body and thermally conductive adhesive, before it can be carried away by the bottom liquid cooling plate. This means that under conditions of high instantaneous heat generation, such as high-rate fast charging, the heat cannot be dissipated in time, and the core temperature of the battery can easily rise sharply. This not only accelerates battery aging but also poses a safety hazard of thermal runaway.

[0003] Secondly, existing cooling solutions suffer from poor temperature uniformity, severely impacting the overall performance and lifespan of the battery pack. Because cooling is concentrated only at the bottom of the battery module, heat dissipation is difficult for cells located further from the cold source, such as those at the top and center of the module, leading to significant temperature differences within the module. This inconsistency causes imbalances in the charge, internal resistance, and degradation rate of individual cells within the battery pack, creating a "weakest link" effect that severely restricts the usable capacity, cycle life, and output power of the entire battery pack.

[0004] Furthermore, existing liquid cooling systems are active cooling systems, whose efficient operation relies on external power components such as water pumps and cooling fans, resulting in high energy consumption and system lag. For instantaneous thermal shocks lasting seconds or even milliseconds, the system cannot respond quickly enough to effectively suppress temperature spikes.

[0005] Meanwhile, the complex active system also introduces potential failure points, affecting the overall reliability of the system. At the same time, to achieve efficient heat conduction, rigid thermally conductive adhesives are commonly used to connect the battery cells and liquid cooling plates. This structure cannot effectively manage the periodic expansion and contraction of the battery cells during charge-discharge cycles. Long-term accumulated mechanical stress may lead to deformation of the battery cell casing, aging or even detachment of the interface material, which in turn increases thermal resistance, creating a vicious cycle of continuously declining performance and reliability.

[0006] Finally, although some studies have attempted to introduce phase change materials (PCMs) to utilize their latent heat of phase change for thermal management, traditional bulk PCM materials have extremely low thermal conductivity. After absorbing heat, the heat cannot be dissipated in time, and they are prone to quickly reaching a "thermal saturation" state and failing, which cannot meet the thermal management requirements for continuous operation of power batteries. Summary of the Invention

[0007] The purpose of this application is to provide a power battery thermal management system that, by introducing a synergistic mechanism of passive heat absorption and active heat conduction, can achieve efficient, uniform and reliable thermal management of the power battery, thereby significantly improving the battery's fast charging performance, cycle life and intrinsic safety level.

[0008] To achieve the above objectives, the present invention provides a power battery thermal management system, comprising: an aluminum-cased battery module, wherein the aluminum-cased battery module is provided with multiple battery cells and multiple integrated cooling buffer units, wherein the integrated cooling buffer units and the battery cells are stacked alternately. The integrated cooling buffer unit includes a thermally conductive substrate and a phase change material composite layer. The thermally conductive substrate and the phase change material composite layer are disposed on both sides of the integrated cooling buffer unit, and the thermally conductive substrate and the phase change material composite layer are respectively in contact with the battery cell. A heat pipe is embedded inside the thermally conductive substrate, and the heat pipe is connected to a condensation section located outside the thermally conductive substrate.

[0009] In an optional embodiment, the heat pipe includes an evaporation section embedded in the thermally conductive substrate; The condensation section is located on the outer side of the thermally conductive substrate.

[0010] In an optional embodiment, the evaporation section includes a flat heat pipe or a loop heat pipe, and the evaporation section is fixedly connected to the thermally conductive substrate by welding or fitting.

[0011] In an optional embodiment, a heat sink is provided on the side of the aluminum-cased battery module. The heat sink includes heat dissipation fins and heat dissipation channels. The condensation section extends outside the thermally conductive substrate and is sealed to the heat dissipation channels.

[0012] In an optional embodiment, the condensation section includes a condenser steam outlet main pipe and a condenser liquid inlet main pipe, which are respectively sealed to the radiator.

[0013] In an optional embodiment, the aluminum-cased battery module is provided with a condenser steam outlet network, which includes a condenser section steam outlet branch pipe corresponding to the integrated cooling buffer unit. The condenser section steam outlet branch pipe is arranged side by side above the battery cell and the integrated cooling buffer unit, and the condenser section steam outlet branch pipe is sealed to the main condenser steam outlet pipe.

[0014] In an optional embodiment, the main liquid inlet pipe of the condenser tube is sealed to the evaporation section on the heat-conducting substrate through the liquid inlet branch pipe of the condenser section.

[0015] In an optional embodiment, the aluminum-cased battery module includes a square frame, the heat sink is attached to the end plate on the side of the square aluminum casing, and the battery cell, the integrated cooling buffer unit and the heat sink are fastened together by straps.

[0016] In an optional embodiment, the phase change material composite layer includes a polymer wall material and a core material encapsulated within the polymer wall material; The core material includes a phase change material and a thermally conductive filler. The phase change material includes paraffin wax, and the thermally conductive filler includes at least one of expanded graphite or graphene.

[0017] In an optional embodiment, the polymer wall material includes a flexible polymer wall material that is elastic and compressible, and the phase change material and the thermally conductive filler are sealed inside the flexible polymer wall material.

[0018] The power battery thermal management system based on microcapsule phase change material coupled with heat pipe in this invention achieves efficient, uniform and reliable thermal management of the power battery through a synergistic mechanism of passive heat absorption and active heat conduction.

[0019] To address the problems of low heat dissipation efficiency, poor temperature uniformity, slow response, lack of stress management, and easy thermal saturation of traditional phase change materials in existing power battery thermal management systems, the power battery thermal management system based on microcapsule phase change materials coupled with heat pipes in this invention introduces a synergistic mechanism of passive heat absorption and active heat conduction, which can achieve efficient, uniform, and reliable thermal management of power batteries, thereby significantly improving the battery's fast charging performance, cycle life, and intrinsic safety level.

[0020] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the overall structure of the power battery thermal management system of this application; Figure 2 This is a schematic diagram of the integrated cooling buffer unit of this application.

[0023] icon: 1-Aluminum-cased battery module; 11-End plate; 2-Battery cell; 3-Integrated cooling buffer unit; 31-Heat-conducting substrate; 32-Phase change material composite layer; 4-Condensing section; 41-Condensing tube steam outlet main pipe; 42-Condensing tube liquid inlet main pipe; 43-Condensing section steam outlet branch pipe; 44-Condensing section liquid inlet branch pipe; 5-Radiator; 51-Radiator fins; 52-Radiator channels; 6-Strap. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0025] In the description of this application, it should be noted that the terms "inner" and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of describing this application and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0026] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "setup" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0027] See Figures 1-2 The power battery thermal management system of the present invention is specifically a power battery thermal management system based on microcapsule phase change material coupled with heat pipe, mainly including: aluminum shell battery module 1, wherein the aluminum shell battery module 1 is provided with multiple battery cells 2 and multiple integrated cooling buffer units 3, wherein the integrated cooling buffer units 3 and the battery cells 2 are stacked alternately. The integrated cooling buffer unit 3 includes a thermally conductive substrate 31 and a phase change material composite layer 32. The phase change material composite layer 32 forms a microcapsule phase change material composite layer 32. The thermally conductive substrate 31 and the phase change material composite layer 32 are disposed on both sides of the integrated cooling buffer unit 3, and the thermally conductive substrate 31 and the phase change material composite layer 32 are respectively in contact with the battery cell 2. A heat pipe is embedded inside the thermally conductive substrate 31, and the heat pipe is connected to a condensation section 4 located outside the thermally conductive substrate 31.

[0028] By coupling microcapsule phase change materials with heat pipes, the problems of long and inefficient traditional bottom liquid cooling heat dissipation paths are solved. The microcapsule phase change materials directly contact the main heating surface of the battery cell 2, and use their latent heat of phase change to absorb a large amount of heat instantaneously, thus achieving the effect of "peak shaving" of battery temperature peaks; at the same time, the embedded heat pipe can quickly conduct heat to the far end for dissipation, just like a "superconducting thermal bridge".

[0029] The synergistic effect of the heat pipe and the microcapsule phase change material composite layer 32 fundamentally optimizes the heat dissipation path, significantly improves the overall heat dissipation efficiency of the system, and effectively suppresses the battery temperature rise under high-rate conditions such as fast charging.

[0030] By directly arranging the integrated cooling buffer unit 3 on the side of the battery cell 2, the effective heat dissipation area is increased. More importantly, the microcapsule phase change material can maintain a near-constant temperature during the phase change process, solving the problem of large temperature differences inside the module in existing technologies.

[0031] Combining the heat pipe's extremely high axial thermal conductivity, heat can be rapidly homogenized in a plane, thereby achieving a "smoothing" effect on the internal temperature of the battery module. This significantly reduces the temperature difference between cells 2 and within cells 2, avoiding inconsistent degradation of the battery pack and extending its overall lifespan.

[0032] The endothermic process of microencapsulated phase change materials is a completely passive physical phase change, with a response speed of milliseconds to instantaneous thermal shocks, providing unparalleled rapid initial protection for the system. Even if the active cooling components temporarily fail, this passive system can still provide valuable safety buffer time, greatly enhancing the reliability and safety of the system and solving the problems of sluggish response and reliance on external power for reliability in active cooling systems.

[0033] The integrated structural design of the aluminum-cased battery module 1 solves the problem of mechanical stress management caused by rigid connections. The microcapsule phase change material composite layer 32 has good elasticity and compressibility, which can adaptively absorb and release the expansion and contraction stress of the cell 2 during cycling, avoiding the risk of rigid interfaces detaching due to fatigue. This "compliant" connection method not only protects the structure of the cell 2, but also ensures the long-term stability of the thermal interface, achieving a unity of thermal management and stress management.

[0034] This application overcomes the technical bottleneck of traditional bulk phase change materials being prone to thermal saturation. By microencapsulating the phase change material composite layer 32 and combining it with a high thermal conductivity filler, the thermal conductivity of the composite material is significantly improved. At the same time, the continuous heat conduction of the heat pipe creates conditions for the "resetting" (i.e., heat release during solidification) of the microcapsules, enabling them to play a repeated and continuous role, thereby achieving long-term and stable thermal management capabilities.

[0035] In terms of further specific structural composition, the heat pipe includes an evaporation section (not shown in the figure), which is embedded in the heat-conducting substrate 31; and a condensation section 4 is disposed on the outer side of the heat-conducting substrate 31.

[0036] The evaporation section includes a flat heat pipe or a loop heat pipe, and the evaporation section is fixedly connected to the thermally conductive substrate 31 by welding or fitting.

[0037] In the above structure, when the evaporation section senses an increase in temperature, the internal working fluid rapidly vaporizes and carries heat to the condensation section 4 located on the outer side or outer end of the module.

[0038] In terms of the specific structure of the evaporation section, the evaporation section includes a flat heat pipe or a loop heat pipe, and the evaporation section is fixedly connected to the heat-conducting substrate 31 by welding or fitting.

[0039] Specifically, the condensing section 4 includes a condenser steam outlet main pipe 41 and a condenser liquid inlet main pipe 42, which are respectively sealed to the radiator 5.

[0040] The function of the heat pipe is to efficiently transfer heat away from the heat source (cell 2), creating conditions for the solidification (resetting) of the phase change material, and mainly playing the role of heat pipe in conducting active heat dissipation.

[0041] Because heat pipes have extremely high axial thermal conductivity, they can quickly redirect heat from locally overheated areas within the module to cooler regions. Combined with the isothermal properties of the phase change material at its phase change temperature, this results in a more uniform temperature distribution throughout the battery module, reducing the maximum temperature difference (ΔT). During charge-discharge cycles, cell 2 undergoes thickness expansion (Δδ). The phase change material composite layer 32 in this system is compressible and can adaptively deform to absorb this mechanical stress, thus preventing interface detachment or damage to cell 2 that might occur with rigid connections. When cell 2 contracts, this elastic layer rebounds, maintaining good interface contact.

[0042] This embodiment employs a coupled structure of heat pipe and flexible composite layer to enhance the system's response speed and reliability. The heat pipe's activation is near instantaneous, and its thermal conductivity far exceeds that of metals, ensuring rapid heat dissipation. Meanwhile, the heat absorption process of the microencapsulated phase change material is a completely passive physical process, resulting in an extremely fast response to thermal shocks. This configuration allows the system to provide strong initial thermal protection even when active cooling components (such as fans) have not yet reached optimal operating conditions or have temporarily failed, solving the problem of lag in active system response and significantly improving the system's inherent reliability and safety.

[0043] Furthermore, a heat sink 5 is provided on the side of the aluminum-cased battery module 1. The heat sink 5 includes heat dissipation fins 51 and heat dissipation channels 52. The condensation section 4 extends outside the thermally conductive substrate 31 and is sealed to the heat dissipation channels 52.

[0044] In addition, the aluminum-cased battery module 1 includes a square frame, and the heat sink 5 is attached to the end plate 11 on the side of the square aluminum casing. The battery cell 2, the integrated cooling buffer unit 3 and the heat sink 5 are fastened together by straps 6. When heat is released in the condensation section 4, it is dissipated into the environment through the heat sink fins 51 by natural convection or an auxiliary fan.

[0045] Furthermore, the aluminum-cased battery module 1 is provided with a condenser steam outlet network, which includes a condenser section steam outlet branch pipe 43 corresponding to the integrated cooling buffer unit 3. The condenser section steam outlet branch pipe 43 is arranged side by side above the battery cell 2 and the integrated cooling buffer unit 3, and the condenser section steam outlet branch pipe 43 is sealed to the condenser steam outlet main pipe 41.

[0046] The aforementioned condenser inlet main pipe 42 is sealed to the evaporation section on the heat-conducting substrate through the condenser section inlet branch pipe 44. The reasonable arrangement of the condenser outlet pipe network can further improve the stability of the entire system.

[0047] The phase change material composite layer 32 in this embodiment may specifically include a polymer wall material and a core material wrapped inside the polymer wall material; The core material includes a phase change material and a thermally conductive filler. The phase change material includes paraffin wax, and the thermally conductive filler includes at least one of expanded graphite or graphene. The polymer wall material may include a flexible polymer wall material with elasticity and compressibility. The phase change material and the thermally conductive filler are sealed inside the flexible polymer wall material.

[0048] Specifically, the phase change material composite layer 32 in this application is a microcapsule phase change material composite layer 32, which integrates microcapsule phase change materials to achieve excellent temperature uniformity and thermal buffering capacity.

[0049] The microcapsule phase change material composite layer 32 consists of a phase change material (such as paraffin) with a phase change temperature matching the battery's optimal operating range (e.g., 45-50℃) as the core material, encapsulated by a polymer wall material to form microcapsules, which are then mixed and cured with high thermal conductivity fillers (such as expanded graphite and graphene). When localized overheating occurs within the battery module, the phase change material in that area preferentially melts and absorbs heat, while the high thermal conductivity of the heat pipe quickly directs excess heat to lower-temperature areas, promoting a more uniform temperature across the entire module. This mechanism effectively solves the problem of large internal temperature differences within the module in existing technologies, avoiding inconsistent battery degradation and thus extending the overall cycle life.

[0050] To further improve the stability of the system throughout its entire life cycle, this invention introduces a stress adaptive management mechanism through the microcapsule phase change material composite layer 32.

[0051] The microcapsule phase change material composite layer 32 not only possesses high thermal conductivity but also good elasticity and compressibility. When the battery cell 2 expands and contracts during charge-discharge cycles, this composite layer can deform like a spring, absorbing and releasing mechanical stress. This avoids the risk of interface delamination or increased thermal resistance caused by stress fatigue in rigid connections (such as thermally conductive adhesives). This technical solution solves the stress management problem, achieving efficient thermal management while ensuring long-term stable contact of the thermal interface and improving the system's durability.

[0052] In this embodiment, the core of the thermal management system lies in the design and application of the integrated cooling buffer unit 3. It consists of a thermally conductive substrate 31, a microcapsule phase change material composite layer 32, and an embedded heat pipe. Its workflow is as follows: When the battery is operating, the heat generated is conducted to the thermally conductive substrate 31. On one hand, the heat is rapidly absorbed by the microcapsule phase change material composite layer 32, which is in close contact with the substrate. The phase change material undergoes a solid-liquid phase change, storing a large amount of latent heat during this process, thereby effectively suppressing the instantaneous peak temperature of the battery. On the other hand, the heat is simultaneously captured by the evaporation section of the heat pipe embedded in the thermally conductive substrate 31, and through the phase change cycle of the working fluid inside the heat pipe, the heat is efficiently transferred to the condensation section 4, which is far from the heat source, and finally dissipated into the environment in the heat dissipation area (such as with heat sink fins and a fan).

[0053] The aforementioned synergistic process of "instant absorption - rapid transport - remote dissipation" fundamentally solves the problems of long and inefficient traditional bottom liquid cooling paths, significantly improves the overall heat dissipation capacity of the system, and ensures the thermal safety of the battery under high-rate conditions.

[0054] The thermal management system of this invention possesses anti-thermal saturation and self-reset capabilities. By microencapsulating the phase change material and combining it with a highly thermally conductive filler, the overall thermal conductivity of the material is significantly improved, preventing localized heat accumulation. More importantly, the continuous and efficient heat dissipation of the heat pipe creates conditions for the microencapsulated phase change material to solidify (release latent heat) when heating stops or under low-power conditions, allowing it to recover from a "thermal saturation" state and thus possess the ability to withstand the next thermal shock. This characteristic overcomes the technical bottleneck of traditional bulk phase change materials being prone to thermal saturation, enabling the system to operate long-term and stably in a cyclical manner.

[0055] This embodiment successfully solves the problems of incomplete thermal management, slow response, and poor temperature uniformity of power batteries in the prior art by adopting technologies such as heat absorption by microcapsule phase change materials, efficient heat conduction by heat pipes, flexible stress buffering, and synergistic anti-saturation. It significantly improves the fast charging capability, safety, reliability, and service life of the power battery system, and has broad application prospects and good social benefits.

[0056] In practical applications, the power battery thermal management system based on microcapsule phase change material and heat pipe coupling in this application mainly relies on the physical properties of the material itself and the structural relationship between components to achieve automatic and passive thermal management and stress management.

[0057] The system is constructed using a typical square aluminum-cased battery module 1 as an example. Multiple cells 2 are stacked alternately with an integrated cooling buffer unit 3 through a "sandwich" structure, that is, an integrated cooling buffer unit 3 is sandwiched between the two large surfaces of each cell 2.

[0058] The unit consists of three parts: a thermally conductive substrate 31 directly bonded to the surface of the battery cell 2; a microcapsule phase change material composite layer 32 fabricated on the other side of the substrate; and a heat pipe embedding the evaporation section within the thermally conductive substrate 31. The entire module is secured to the battery by end plates 11 and straps 6. At room temperature or when the battery is operating at low power, the microcapsule phase change material is in a solid state, and the composite layer acts as a highly thermally conductive solid interface.

[0059] Next is the system's passive response to heat load. When the battery enters fast charging or high-rate discharging mode, the heat generation increases sharply.

[0060] Heat transfer: The heat generated by the battery cell 2 is first conducted to the thermally conductive substrate 31.

[0061] Phase change endothermic effect (passive peak clipping): When the substrate temperature rises to the melting point of the phase change material (e.g., 45°C), the microcapsule phase change material composite layer 32 in contact with it begins to absorb heat and melts from a solid to a liquid state. This phase change process absorbs a large amount of latent heat (Q = m•L, where m is the material mass and L is the latent heat of phase change) at a nearly constant temperature, thereby effectively suppressing the sharp rise in temperature at the interface with the cell 2 and achieving the "peak clipping" effect on temperature spikes. This process is entirely driven by material properties and thermodynamic laws, requiring no external control.

[0062] Heat pipe conduction (active heat dissipation): Almost simultaneously, the evaporation section of the heat pipe embedded in the substrate senses the temperature rise, and the internal working fluid rapidly vaporizes, carrying heat to the condensation section 4 located on the side or end of the module. The heat is released in the condensation section 4 and dissipated into the environment through the heat dissipation fins 51 via natural convection or an auxiliary fan. The role of the heat pipe is to efficiently transfer heat away from the heat source (cell 2), creating conditions for the solidification (resetting) of the phase change material.

[0063] At the same time, the system achieves temperature uniformity and stress buffering.

[0064] Temperature equalization mechanism: Due to the extremely high axial thermal conductivity of the heat pipe, it can quickly guide heat from locally overheated areas in the module to areas with lower temperatures. Combined with the isothermal characteristics of the phase change material at the phase change temperature, the combined effect makes the temperature distribution of the entire battery module more uniform and reduces the maximum temperature difference (ΔT).

[0065] Stress buffering mechanism: During charge-discharge cycles, cell 2 undergoes thickness expansion (Δδ). The elastic porous thermally conductive layer in this system, namely the microcapsule phase change material composite layer 32 comprising the core material and highly thermally conductive filler, is compressible and can adaptively deform to absorb this mechanical stress, thereby avoiding interface delamination or damage to cell 2 that may be caused by rigid connections. When cell 2 contracts, the elastic layer rebounds, maintaining good contact at the interface.

[0066] Finally, the system is reset and prepared. When high-rate operation ends, the battery's heat generation decreases. The heat pipe continuously removes residual heat, causing the temperature of the phase change material composite layer 32 to gradually decrease. When the temperature falls below the phase change point, the liquid phase change material re-solidifies, releasing latent heat which is then dissipated through the heat pipe. At this point, the system completes one operating cycle, returns to its initial state, and prepares to cope with the next thermal shock.

[0067] In summary, this embodiment clearly demonstrates how this thermal management system, through its unique structural design, achieves completely passive, highly efficient, and reliable thermal and stress management based on physical principles. Its effectiveness does not depend on complex control algorithms, but rather on the inherent properties of the materials and the mechanical structure.

[0068] The thermal management system of this invention has the following technical effects: Cooling buffer integrated unit 3: By integrating the thermally conductive substrate 31, the microcapsule phase change material composite layer 32 and the heat pipe evaporation section into an independent standardized component, the cooling buffer integrated unit 3 can be flexibly sandwiched between adjacent cells 2 like a "sandwich", forming the basic skeleton of the entire thermal management system. This realizes the plug-and-play functionality of the thermal management module, simplifies the module assembly process, and improves the consistency and reliability of the system.

[0069] Microcapsule phase change material composite layer 32: The passive heat absorption characteristics of the microcapsule phase change material composite layer 32 are synergistically coupled with the active and efficient heat conduction characteristics of the heat pipe. The microcapsule phase change material composite layer 32 is responsible for absorbing a large amount of heat instantaneously to "shaving off the peak," while the heat pipe is responsible for quickly dissipating heat to avoid "heat saturation." The two are deeply integrated in terms of physics and function, which solves the inherent defects of single technologies (pure microcapsule phase change material composite layer 32 or pure heat pipe) and achieves good thermal management effect.

[0070] Passive thermal management methods: Through a completely passive thermal management approach, an efficient heat absorption, temperature equalization, and conduction process can be achieved. This process does not rely on external active control signals but is driven solely by the physicochemical properties of the material itself (latent heat of phase change, capillary force, etc.) and the laws of thermodynamics. This method offers extremely fast response times (milliseconds), high reliability, and no additional energy consumption, providing intrinsically safe thermodynamic protection for the battery.

[0071] Integrated design of thermal management and stress management The thermal management function and mechanical stress management function are integrated through an elastic porous thermal conductive layer. While serving as an efficient heat conduction path, the inherent elasticity and compressibility of this composite layer can adaptively absorb and release the expansion and contraction stress generated by the cell 2 during cycling, avoiding the risk of interface failure caused by rigid connection, and realizing the coordinated management of thermo-mechanical dual physical fields.

[0072] Side-facing thermal management interface layout: This invention breaks through the limitations of traditional bottom cooling layouts by placing the main thermal management interface on the side of cell 2 where heat generation is more concentrated and the surface area is larger. This side layout greatly increases the effective heat dissipation area, optimizes the heat transfer path from the heat-generating core to the cooling unit, and structurally lays the foundation for efficient heat dissipation and excellent temperature uniformity.

[0073] The system's resistance to thermal saturation and self-reset capability: The system of this invention possesses inherent resistance to thermal saturation and periodic self-reset capability. The continuous heat dissipation of the heat pipe creates conditions for the solidification and recrystallization of the microcapsule phase change material after the heat load is reduced, enabling the system to recover from an endothermic state. This allows it to repeatedly and continuously cope with multiple intermittent high-power thermal shocks, ensuring the long-term stability of thermal management performance.

[0074] It should be noted that, where there is no conflict, the features in the embodiments of this application can be combined with each other.

[0075] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A power battery thermal management system, characterized in that, include: An aluminum-cased battery module, wherein the aluminum-cased battery module is provided with multiple battery cells and multiple integrated cooling buffer units, wherein the integrated cooling buffer units and the battery cells are stacked alternately; The integrated cooling buffer unit includes a thermally conductive substrate and a phase change material composite layer. The thermally conductive substrate and the phase change material composite layer are disposed on both sides of the integrated cooling buffer unit, and the thermally conductive substrate and the phase change material composite layer are respectively in contact with the battery cell. A heat pipe is embedded inside the thermally conductive substrate, and the heat pipe is connected to a condensation section located outside the thermally conductive substrate.

2. The power battery thermal management system according to claim 1, characterized in that, The heat pipe includes an evaporation section, which is embedded in the heat-conducting substrate. The condensation section is located on the outer side of the thermally conductive substrate.

3. The power battery thermal management system according to claim 2, characterized in that, The evaporation section includes a flat heat pipe or a loop heat pipe, and the evaporation section is fixedly connected to the thermally conductive substrate by welding or embedding.

4. The power battery thermal management system according to claim 2, characterized in that, A heat sink is provided on the side of the aluminum-cased battery module. The heat sink includes heat dissipation fins and heat dissipation channels. The condensation section extends outside the thermally conductive substrate and is sealed to the heat dissipation channels.

5. The power battery thermal management system according to claim 4, characterized in that, The condensation section includes a condenser tube steam outlet main pipe and a condenser tube liquid inlet main pipe, which are respectively sealed to the radiator.

6. The power battery thermal management system according to claim 5, characterized in that, The aluminum-cased battery module is provided with a condenser steam outlet network. The condenser steam outlet network includes a condenser section steam outlet branch pipe that is provided corresponding to the integrated cooling buffer unit. The condenser section steam outlet branch pipe is arranged side by side above the battery cell and the integrated cooling buffer unit, and the condenser section steam outlet branch pipe is sealed to the main condenser steam outlet pipe.

7. The power battery thermal management system according to claim 5, characterized in that, The liquid inlet main pipe of the condenser tube is sealed to the evaporation section on the heat-conducting substrate through the liquid inlet branch pipe of the condenser section.

8. The power battery thermal management system according to claim 5, characterized in that, The aluminum-cased battery module includes a square frame, and the heat sink is attached to the end plate on the side of the square aluminum casing. The battery cell, the integrated cooling buffer unit, and the heat sink are fastened together by straps.

9. The power battery thermal management system according to any one of claims 1-8, characterized in that, The phase change material composite layer includes a polymer wall material and a core material encased inside the polymer wall material; The core material includes a phase change material and a thermally conductive filler. The phase change material includes paraffin wax, and the thermally conductive filler includes at least one of expanded graphite or graphene.

10. The power battery thermal management system according to claim 9, characterized in that, The polymer wall material includes a flexible polymer wall material that is elastic and compressible, and the phase change material and the thermally conductive filler are sealed inside the flexible polymer wall material.

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