Cold plate embedded battery box structure, preparation method and vehicle

Abstract

The present application relates to the technical field of automobiles, and in particular to a cold plate embedded battery box structure, a preparation method and a vehicle. A sandwich core configuration is adopted, and from top to bottom, the sandwich core configuration comprises: an upper skin layer, which is a fiber reinforced composite material; a core layer, which comprises an embedded liquid cooling component, a light core material and a metal reinforcing layer; and a lower skin layer, which is a fiber reinforced composite material; wherein the liquid cooling component, the light core material and the metal reinforcing layer are all wrapped between the upper skin layer and the lower skin layer, and are integrally formed with the upper skin layer and the lower skin layer. By deeply embedding the liquid cooling component in the sandwich core structure of the fiber reinforced composite material, the risk of high-voltage short circuit caused by leakage of the cooling liquid is eliminated, and even if leakage occurs, the cooling liquid will be limited in the closed core space or absorbed by the light core material, ensuring the extreme safety of the battery system.

Description

Technical Field

[0001] This invention relates to the field of automotive technology, and in particular to a cold plate embedded battery box structure, its manufacturing method, and a vehicle thereof. Background Technology

[0002] With the rapid development of the new energy vehicle industry, lightweighting and thermal management integration technologies for power battery packs have become core directions for improving vehicle range and safety. Currently, battery enclosures typically use aluminum alloy stamping and welding or single-layer composite material trays as load-bearing structures, coupled with independent liquid cooling systems. In existing liquid cooling arrangements, liquid cooling plates are mostly installed on the inner or outer surface of the tray base plate using thermally conductive adhesive or mechanical fasteners. Furthermore, to meet high-voltage insulation requirements, the surface of the liquid cooling plate needs to be additionally covered with an insulating film or thermally conductive insulating pad, and relies on a separate metal protective plate to withstand physical impacts from the bottom.

[0003] The aforementioned traditional solutions have significant limitations in practical applications. If a coolant leak occurs in a separately installed liquid cooling plate, the liquid can easily flow directly to the battery module or high-voltage connection area, causing a short circuit and potentially triggering thermal runaway. Furthermore, the multi-layered, independent structure consisting of the tray base plate, cold plate, and protective plate exhibits significant interfacial thermal resistance and structural redundancy, increasing both the overall weight and manufacturing costs due to the complex assembly process. In addition, the interfacial bonding between composite materials and dissimilar metal materials is weak, making them prone to delamination, peeling, or relative slippage under long-term vehicle vibration and complex temperature fluctuations, severely impacting the structural reliability of the battery system and the long-term stability of the heat dissipation path. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned shortcomings in the prior art by proposing a cold plate embedded battery box structure, manufacturing method, and vehicle.

[0005] To achieve the above objectives, the present invention provides a cold plate embedded battery box structure, which adopts a sandwich configuration and comprises, from top to bottom: The upper skin layer is a fiber-reinforced composite material; The sandwich layer includes an embedded liquid cooling component, a lightweight core material, and a metal reinforcement layer; The lower skin layer is a fiber-reinforced composite material; The liquid cooling component, the lightweight core material, and the metal reinforcing layer are all wrapped between the upper skin layer and the lower skin layer, and are integrally formed with the upper skin layer and the lower skin layer.

[0006] This technical solution integrates liquid cooling components, lightweight core materials, and metal reinforcement layers into a single unit, completely encasing them between upper and lower composite material skins. This not only achieves a high degree of integration of load-bearing, heat dissipation, and protection functions, reducing the overall weight, but more importantly, it completely isolates the cooling medium from the battery module and high-voltage connection area in physical space. Even if the liquid cooling component is damaged and leaks, the coolant will be confined within the closed sandwich space, fundamentally eliminating the risk of battery short circuits and thermal runaway caused by coolant overflow.

[0007] Preferably, the liquid cooling component is disposed adjacent to the upper skin layer, the metal reinforcing layer is disposed adjacent to the lower skin layer, and the lightweight core material is disposed between the liquid cooling component and the metal reinforcing layer. This specific stacking layout balances thermal management efficiency and physical safety. Distributing the liquid cooling component adjacent to the upper skin shortens the heat transfer path between it and the bottom of the battery cell, ensuring real-time response of heat dissipation performance. Distributing the metal reinforcing layer adjacent to the lower skin fully utilizes its impact and puncture resistance, providing the most direct physical protection barrier for the internal battery and liquid cooling system when the vehicle encounters bottom scraping or gravel impacts.

[0008] Preferably, the liquid cooling component is an aluminum product with no insulating coating on its outer surface, and the outer surface of the liquid cooling component has a conversion film layer formed by passivation treatment. This technical solution completely seals the liquid cooling component inside a composite material skin with insulating properties, replacing the expensive and cumbersome insulating coating or PET film on the surface of aluminum liquid cooling components. This can significantly reduce material costs and processing steps while eliminating the additional thermal resistance caused by the insulating layer, significantly improving heat exchange efficiency. The conversion film layer formed by passivation treatment provides a chemically active basis for the subsequent high-strength bonding of dissimilar materials.

[0009] Preferably, the conversion film layer is a micro-rough structure layer with micron- or nano-sized pores, and the conversion film layer forms a mechanically interlocked structure with the resin matrix in the upper skin layer. This technical solution utilizes the micron- or nano-sized pore characteristics of the conversion film layer, allowing the resin matrix of the upper skin layer to fully penetrate and fill these microstructures during the molding process. This creates a deep physical anchoring and mechanical interlocking effect at the interface between the liquid-cooled component and the composite material, effectively solving the problem of peeling and delamination that easily occurs between aluminum alloy and resin materials under long-term vibration or temperature cycling due to the difference in thermal expansion coefficients, thus ensuring the long-term reliability of the structure.

[0010] Preferably, the lightweight core material is one or more of reinforced polyurethane foam, modified polyphenylene ether foam, or epoxy-modified polyamide foam; the metal reinforcing layer is a steel plate with a passivated surface. This technical solution uses rigid structural foams such as reinforced polyurethane, modified polyphenylene ether, or epoxy-modified polyamide, which can provide excellent compressive strength and energy absorption characteristics while maintaining extremely low density. Together with the passivated steel plate, they form a high-rigidity, high-toughness support matrix, enabling the battery tray to meet the modal requirements and load-bearing needs under complex road conditions while possessing excellent collapse energy absorption and bottom intrusion resistance.

[0011] Preferably, the reinforcing fibers in the upper and lower skin layers are continuous glass fibers, and the upper skin layer contains a high thermal conductivity modified filler. This technical solution uses continuous glass fibers as reinforcement, giving the skin layer tensile and flexural moduli far exceeding those of chopped fibers, ensuring the structural stability of the housing under heavy loads. By adding a high thermal conductivity modified filler to the upper skin layer, the low thermal conductivity of the resin matrix is ​​effectively compensated for, allowing the heat generated by the battery module to be rapidly transferred to the liquid cooling components below through the thin skin layer, achieving a dual improvement in mechanical properties and thermal management performance.

[0012] Preferably, the liquid cooling component, the lightweight core material, the metal reinforcing layer, and the two skin layers are separated by resin injected through a high-pressure resin transfer molding process, which fills the interfacial gaps and cures to form a physical-chemical bonded interface without adhesives. This technical solution utilizes the powerful penetration of the high-pressure resin transfer molding process, allowing the resin to completely fill the extremely small interfacial gaps between the pre-installed functional components. After curing, it forms a continuous and dense physical-chemical bonded network, completely eliminating the need for thermally conductive adhesives, structural adhesives, or mechanical fasteners used in traditional processes to connect the components. This eliminates interfacial thermal resistance, achieves truly seamless integrated manufacturing, simplifies the supply chain process, and improves mass production speed.

[0013] The second aspect of this invention provides a method for preparing a cold-plate embedded battery box structure, used to prepare the cold-plate embedded battery box structure described in the first aspect of this invention, specifically including the following steps: S1: The liquid cooling component, the lightweight core material, and the metal reinforcing layer after surface passivation treatment are combined in a predetermined order and placed in a mold together with the fiber preform used to form the upper skin layer and the lower skin layer. S2: After closing the mold, inject resin into the mold under high pressure, so that the resin impregnates the fiber preform and fills the interface gaps between the fiber preform and the liquid cooling plate, and between the fiber preform and the steel plate; and control the resin not to enter the gaps between the foam and the liquid cooling plate, and between the foam and the steel plate; S3: After the resin has cured, demold to obtain the cold plate embedded battery box structure.

[0014] The preparation method provided by this technical solution directly performs high-pressure injection molding of various dissimilar material functional components and fiber preforms in a mold after surface passivation treatment. This realizes one-step manufacturing from raw materials to complex integrated components, completely eliminating the cumbersome secondary bonding, sealing test and mechanical fastening processes in traditional processes. While improving the degree of production automation and product size consistency, it ensures that a continuous and gapless structured connection can be formed between the interfaces of each material layer.

[0015] Furthermore, in step S2, the resin injection pressure is controlled between 10 bar and 60 bar, and the injection time is less than 1 minute; in step S3, the resin is rapidly cured and molded within 2 to 5 minutes. This technical solution, by precisely controlling the injection pressure between 10 bar and 60 bar and combining it with an extremely short injection and curing cycle, not only ensures that the resin can quickly and thoroughly impregnate high-density continuous fibers and expel air bubbles, eliminating microstructural defects, but also shortens the production cycle of a single product to within a few minutes. While ensuring that the product possesses extremely high interfacial bonding strength and thermal conductivity efficiency, it perfectly matches the large-scale, high-quality, and low-cost rapid mass production requirements of core components for new energy vehicles.

[0016] A third aspect of the present invention provides a vehicle in which the vehicle body battery pack is manufactured using the cold plate embedded battery box structure of the first aspect and / or the preparation method of the second aspect.

[0017] The vehicle provided by this technical solution achieves system-level lightweighting at the chassis level by integrating the cold plate embedded battery box structure, which can significantly improve the vehicle's range and power response performance. More importantly, thanks to the excellent leakage prevention safety, chassis impact resistance and efficient thermal management performance of this technical solution, the risk of thermal runaway under extreme conditions is greatly reduced, providing users with a green travel solution with a longer service life, higher safety level and better energy efficiency.

[0018] Compared with the prior art, the cold plate embedded battery box structure, manufacturing method, and vehicle disclosed in this invention have the following significant advantages: This invention eliminates the risk of high-voltage short circuits caused by coolant leakage by deeply embedding the liquid cooling component within a sandwich structure of fiber-reinforced composite material. Even if leakage occurs, the coolant is confined within the closed sandwich space or absorbed by the lightweight core material, ensuring the extreme safety of the battery system. At the same time, thanks to the high integration of the liquid cooling component with the upper skin layer and the elimination of the traditional insulating coating layer, the heat transfer path is significantly shortened. Combined with the application of highly thermally conductive modified fillers, the interfacial thermal resistance is reduced, improving the thermal management efficiency of the battery pack during high-speed charging and discharging.

[0019] On the other hand, this invention utilizes an integrated molding process and interface passivation technology to construct a nanoscale micro-rough structure on the surface of aluminum / steel metals, achieving strong mechanical interlocking and chemical bonding between dissimilar materials, effectively solving the problem of delamination and peeling under long-term vibration environment; this integrated design of skin-core material-reinforcing layer transforms the liquid cooling component from a single heat dissipation element into a structural component that participates in load-bearing, significantly improving the overall rigidity and impact resistance of the enclosure while achieving a weight reduction of more than 30%, and reducing the total manufacturing cost and production cycle by eliminating complex secondary assembly processes and auxiliary fasteners. Attached Figure Description

[0020] Figure 1 This is a structural diagram of the cold plate embedded battery box of the present invention; Figure 2 This is a three-dimensional view of the skin layer of the present invention; Figure 3 This is a perspective view of the lightweight foam of the present invention; Figure 4 This is a perspective view of the metal reinforcement layer of the present invention; Figure 5 This is a perspective view of the lower plate of the liquid cooling plate of the present invention; Figure 6 This is a perspective view of the liquid cooling plate of the present invention. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Example 1

[0022] Please see the appendix Figure 1-6 This embodiment provides a cold-plate embedded battery box structure, which is mainly used for bottom load-bearing and thermal management integration of power battery packs in new energy vehicles. This box structure adopts a sandwich core configuration and is integrally formed through high-pressure resin transfer molding (HP-RTM) process. Specifically, this box structure includes, from top to bottom: Upper skin layer 1: The upper skin layer is made of continuous glass fiber reinforced composite material.

[0023] Furthermore, in order to improve heat dissipation efficiency, a high thermal conductivity modified filler is added to the resin matrix of the upper skin layer. The high thermal conductivity modified filler can be one of alumina, boron nitride or graphite powder. Furthermore, the thickness of the upper skin layer is preferably controlled between 0.2 mm and 1.5 mm. This thin and highly thermally conductive design allows the heat generated by the upper battery cell to be transferred to the liquid cooling system below through a very short path.

[0024] The upper skin layer adopts a composition design of continuous glass fiber reinforced composite material combined with high thermal conductivity modified filler. Combined with a thin layer structure of 0.2mm to 1.5mm, while ensuring excellent structural strength and electrical insulation performance of the top of the box, the interfacial thermal resistance is significantly reduced and the heat transfer path is shortened through the synergistic effect of material thermophysical property modification and structural physical size reduction. This ensures that the heat of the cell can be quickly and evenly transferred to the liquid cooling system, effectively improving the thermal management response speed and temperature control reliability of the battery system under complex operating conditions.

[0025] Preferably, the resin matrix of the upper skin layer is a low-viscosity epoxy resin, and its reinforcing fibers are made of multi-layer continuous glass fiber woven fabric or multi-axial fabric with a thickness of 0.2 mm to 0.4 mm. The mass fraction of the high thermal conductivity modified filler is 15% to 35%, wherein the high thermal conductivity modified filler can be boron nitride. By using low-viscosity epoxy resin and specific multi-layer continuous fiber fabric, it is ensured that the resin can fully impregnate the fiber gaps and filler particles under high pressure, eliminating internal micropores, thereby achieving high structural strength and toughness while maintaining an ultra-thin thickness; combined with 15% to 35% high mass fraction of boron nitride filler, the composite material has excellent electrical insulation properties while obtaining good intrinsic thermal conductivity, providing an efficient material basis for the rapid heat dissipation of the battery system.

[0026] Preferably, to further optimize the interfacial thermal resistance, the surface of the upper skin layer near the cell has a micro-flatness structure formed by die pressing, wherein the micro-flatness structure has a flatness error of less than 0.1 mm / m. 2 Ideally, this significantly reduces the amount of thermal grease used. The surface of the upper skin layer, through high-precision molding with a micro-flat structure, improves the physical morphology of the contact and fit between the casing and the bottom of the battery cell, achieving a fit of less than 0.1 mm / m. 2 The control of flatness further reduces the interfacial contact thermal resistance; this not only significantly reduces the amount of expensive thermal grease used, lowers production costs and lightens system weight, but also avoids hot spot accumulation caused by uneven grease application, further ensuring the consistency and efficiency of the temperature control system.

[0027] By strictly controlling the thickness from 0.2 mm to 1.5 mm, the equivalent thermal conductivity of the upper skin layer can be effectively improved while maintaining the insulation strength. Combined with the elimination of the PET film, the total thermal resistance from the cell to the coolant can be reduced by at least 30% to 50%.

[0028] Sandwich layer: The sandwich layer is the core functional layer of this solution. It contains, from top to bottom, a liquid cooling component 2, a lightweight core material 3, and a metal reinforcing layer 4.

[0029] Liquid-cooled components: located at the top of the sandwich layer, closely attached to the upper skin layer.

[0030] Furthermore, the liquid cooling components are made of aluminum alloy, featuring a brazed upper and lower aluminum plate structure or a multi-channel harmonica tube structure. The liquid cooling components are completely encased in an insulating composite material skin, eliminating the need for traditional PET film or insulating coatings on their outer surface, thus removing additional thermal resistance. To enhance adhesion, the outer surface of the liquid cooling components undergoes passivation treatment, forming a conversion film layer with nanoscale pores.

[0031] This sandwich layer highly integrates aluminum liquid cooling components, lightweight core materials, and metal reinforcing layers, allowing the liquid cooling components to adhere tightly to the skin layer and be completely wrapped by insulating composite materials. This cleverly eliminates the need for traditional additional insulating films or coatings, removes redundant interfacial thermal resistance, and significantly improves the system's heat exchange efficiency. At the same time, the nanoscale porous conversion film layer on the surface of the liquid cooling components can form a strong micro-mechanical interlock with the injection molding resin, solving the problem of interfacial bonding between heterogeneous materials. This effectively avoids delamination failure that may occur under complex alternating hot and cold conditions, and significantly improves the long-term structural stability and operational reliability of the overall enclosure structure.

[0032] Preferably, the conversion film layer on the surface of the liquid-cooled component is formed by pickling with ferric chloride solution and impregnation with silane coupling agent, and the average pore size of the micropores is controlled between 100 nm and 500 nm. The 100 nm to 500 nm microporous conversion film prepared by the specific process can promote the resin to penetrate deep into the pores to form strong nanoscale mechanical interlocking and chemical bonding, thereby eliminating the risk of delamination between aluminum alloy and composite material under alternating hot and cold temperatures and improving the overall bonding stability.

[0033] Preferably, the inlet and outlet of the liquid cooling component are pre-installed with metal bushings or flanges. The outer surface of the bushing also has a conversion film, which is completely sealed by resin during the molding process. The pre-installed membrane-coated metal bushings at the inlet and outlet are seamlessly wrapped with resin, which not only avoids the aging and stress concentration risks of traditional mechanical seals, but also cuts off the coolant leakage path at the source, achieving system-level leak prevention.

[0034] Preferably, the internal flow channels of the liquid cooling component are designed with a directional reinforcement structure, and the channel wall thickness is adaptively thickened in areas of concentrated stress, allowing it to function as both a heat dissipation element and a transverse reinforcing beam for the housing. This localized thickening design in the stress-bearing areas of the internal flow channels enables the liquid cooling plate to function as both a heat sink and a transverse reinforcing beam. This ensures safe high-pressure fluid circulation while eliminating the need for additional structural components, achieving significant weight reduction of the housing and freeing up internal space.

[0035] The nanoscale conversion film and the high-pressure resin injected during molding form a mechanical interlock. Verified results show a peel strength exceeding 15 MPa, completely solving the delamination problem caused by alternating hot and cold temperatures between aluminum alloys and composite materials. Simultaneously, the integrated wrapping of the inlet and outlet achieves a zero-leakage system seal. Lightweight core material: placed between the liquid cooling component and the metal reinforcement layer.

[0036] Furthermore, the lightweight core material is made of rigid reinforced polyurethane (RPU) foam. This foam not only reduces weight and provides thermal insulation, but also provides energy-absorbing cushioning when compressed, protecting the liquid cooling components above from damage.

[0037] Preferably, the density of the RPU foam is 150 kg / m³. 3 Up to 300 kg / m 3 It features a closed-cell structure with a closed-cell ratio greater than 95%. Drainage collection channels are pre-installed within the foam layer in high-risk areas such as near liquid-cooled component joints. A density of 150 kg / m³ is used. 3 Up to 300 kg / m 3 Furthermore, the rigid polyurethane foam with a closed-cell rate of over 95%, combined with the local drainage collection tank design, not only achieves system lightweighting and bottom insulation, but also effectively protects the upper liquid cooling components from compression damage through its excellent energy absorption and buffering performance, and provides a safety net for leakage diversion in high-risk areas such as joints.

[0038] Preferably, the thickness of the foam core material is designed with a gradient based on the stress distribution in different parts of the battery box, with a thinner central load-bearing area and a thicker perimeter for collision protection. By thickening the perimeter to enhance the edge's resistance to side impacts and absorb energy, while thinning the central area to maximize internal space utilization and reduce overall weight, this gradient thickness design based on stress distribution achieves a balance between lightweight design, spatial arrangement, and collision safety performance of the battery box.

[0039] The closed-cell structure not only provides excellent structural rigidity, but also acts as a secondary defense: even if the liquid cooling components leak through microcracks, the high-density closed-cell foam can block the coolant in a local area, delaying or even preventing the liquid from penetrating towards the battery cell; at the same time, the low thermal conductivity of the foam layer effectively blocks the conduction of high temperature from the bottom road surface to the battery pack.

[0040] Metal reinforcement layer: Located at the bottom of the core layer, adjacent to the lower skin layer.

[0041] Preferably, the metal reinforcement layer is made of high-strength steel plate with a passivated surface. This steel plate, as the first line of impact protection at the bottom of the pallet, combined with the composite material skin, can effectively resist point load impacts from road gravel or bottom scraping.

[0042] Preferably, the high-strength steel plate has a tensile strength of not less than 1000 MPa and a thickness of 0.6 mm to 1.2 mm. While occupying minimal chassis space and achieving extreme lightweighting, it provides excellent puncture resistance and high load-bearing capacity for the bottom of the enclosure.

[0043] Preferably, the passivation layer on the surface of the high-strength steel plate can be one or more of a zinc-rich coating and a phosphate layer, which can form a strong chemical bond with the resin matrix. Specific passivation layers such as zinc-rich coatings or phosphate layers not only significantly improve the corrosion resistance life of the underlying metal, but also form a strong chemical bond with the resin matrix, effectively preventing the risk of delamination at the metal-non-metal interface under harsh working conditions.

[0044] Preferably, the high-strength steel plate adopts a locally reinforced mesh or a thin plate structure with reinforcing ribs, thereby increasing the overall vehicle energy density by reducing weight. While ensuring that the underbody protection plate has excellent structural rigidity and bending and torsional strength, the aforementioned structure can reduce the weight of the metal layer to the greatest extent, thereby significantly improving the mass packing efficiency of the battery system and the overall vehicle energy density.

[0045] The combination of high-strength steel plates and the lower skin layer forms a composite protection system similar to bulletproof vest. When the enclosure is impacted by a sharp object at the bottom, the steel plates are responsible for puncture resistance, the composite skin is responsible for absorbing impact energy, and the foam layer is responsible for cushioning. This triple protection ensures that the internal liquid cooling system and battery module are not mechanically damaged.

[0046] Lower skin layer 5: The lower skin layer is also made of glass fiber reinforced composite material, which together with the upper skin layer forms the outer shell of the box and completely seals the three components of the sandwich layer inside.

[0047] In this embodiment, the liquid cooling component, lightweight core material, and metal reinforcing layer are not connected by traditional adhesives or bolts, but are integrated using resin injected in the HP-RTM process. During the molding process, the high-pressure injected resin fully impregnates the fiber fabric of the skin layer and fills the pores of the passivation film on the surface of the liquid cooling component, the pore structure of the lightweight core material, and the rough surface structure of the metal reinforcing layer.

[0048] After curing, the resin matrix and the conversion film layer on the surface of the liquid cooling component form a microscopic mechanical interlocking structure, and physical-chemical bonding forces are generated at the interface. This connection method makes the box structure appear as an inseparable whole on a macroscopic scale, and even under severe vibration or frequent thermal cycling, the layers of material will not peel off or shift relative to each other.

[0049] When the enclosure is put into use, the bottom of the battery cell is placed directly above the upper skin layer. Heat is transferred directly to the embedded aluminum liquid cooling component through the thin, thermally conductive upper skin layer, and the heat is carried away by the coolant inside the liquid cooling component. Because the liquid cooling component is embedded in the middle of the closed sandwich structure, even if the liquid cooling component leaks coolant due to quality defects or extreme impacts, the leaked liquid will be confined within the cavity sealed by the upper and lower skins, or absorbed by the foam core material in the middle layer, and will not come into contact with the high-voltage battery cell and connector above, thus physically eliminating the risk of short circuits.

[0050] Furthermore, since the liquid cooling component itself participates in the overall stress as part of the sandwich structure, it is no longer just a heat dissipation accessory, but a reinforcing component that enhances the longitudinal stiffness of the tray. Together with the bottom steel plate and composite material skin, it achieves a synergistic integration of load-bearing, protection and heat dissipation. Example 2

[0051] This embodiment provides an integrated fabrication method for a cold-plate embedded battery box structure based on HPRTM (High Voltage Resin Transfer Molding) technology. This method integrates load-bearing, heat dissipation, and bottom protection functions in the same molding process, specifically including the following steps: S1: The liquid cooling component, the lightweight core material, and the metal reinforcing layer, after surface passivation treatment, are combined in a predetermined order and placed in a mold together with the fiber preform used to form the upper skin layer and the lower skin layer.

[0052] Specifically, the core insert undergoes surface treatment. Liquid-cooled components employing an aluminum top and bottom plate brazed structure or a harmonica tube structure have their surface insulating materials (such as PET film or thermally conductive insulating pads) removed, and their outer surface is chemically passivated to form a conversion film with micro-roughness and chemical activity. Simultaneously, a high-strength steel plate with impact-resistant bottom is selected as a metal reinforcement layer, and its surface is also passivated.

[0053] The layers are laid up in a predetermined order within the HPRTM molding die. At the bottom of the die, a lower fiberglass preform for forming the lower skin layer, a passivated steel plate, a rigid structural foam, and a passivated liquid cooling component are placed sequentially. Finally, an upper fiberglass preform for forming the upper skin layer is placed on top. The rigid structural foam is one or more of RPU, MPPE, and EPA.

[0054] By performing surface passivation treatment on liquid cooling components and metal reinforcement layers, and combining them with specific in-mold preset combinations, traditional insulating media are eliminated from the source to significantly improve thermal management efficiency and simplify assembly processes. At the same time, a strong physical-mechanical interlocking and chemical bonding between dissimilar materials is constructed by utilizing the micro-rough chemically active conversion film formed on the metal surface. This lays a solid foundation for the subsequent realization of high-strength integrated integration of battery box structure load-bearing, heat dissipation and protection functions.

[0055] S2: After closing the mold, high pressure is applied to inject resin into the mold to impregnate the fiber preform and fill the interface gaps between the fiber preform and the liquid cooling plate, and between the fiber preform and the steel plate; while controlling the resin not to enter the gaps between the foam and the liquid cooling plate, and between the foam and the steel plate.

[0056] The mold is fully closed and locked, and then the resin matrix is ​​injected into the mold cavity under high pressure. In this embodiment, the process parameters are precisely controlled by the HPRTM injection equipment: the resin injection pressure is controlled between 10 bar and 60 bar, and the injection time is strictly controlled to be less than 1 minute.

[0057] Under this high pressure and extremely short injection time, the resin can rapidly and thoroughly impregnate the upper and lower layers of fiberglass preforms, while controlling the resin not to fill between the liquid-cooled component and the foam, nor between the foam and the steel plate. During this process, the polar resin forms nanoscale mechanical interlocks and strong chemical bonds with the passivated aluminum liquid-cooled component and steel plate surfaces within the filled area; simultaneously, the foam itself directly adheres to the passivated aluminum liquid-cooled component and steel plate surfaces, forming a strong interface layer between them.

[0058] By precisely controlling the high-pressure injection from 10 bar to 60 bar within an extremely short injection time, not only is rapid and thorough impregnation of the resin into the glass fiber preform and seamless filling of the interface gaps achieved, but the polar resin is also more effectively driven to deeply fuse with the passivated metal surface, forming nanoscale mechanical interlocking and strong chemical bonding. This significantly improves production efficiency while ensuring the structural integrity and anti-peeling reliability of the multi-layer dissimilar material interface under complex working conditions.

[0059] S3: After the resin has cured, demold to obtain the cold plate embedded battery box structure.

[0060] After the resin is injected, the mold temperature is maintained to allow the resin to undergo a rapid cross-linking reaction. Thanks to the characteristics of the HPRTM process, the resin can be rapidly cured and molded within 2 to 5 minutes.

[0061] After the resin has fully cured, open the mold and demold to obtain a complete sandwich-shaped cold plate embedded battery box structure.

[0062] The housing manufactured using the above process completely encapsulates the liquid-cooled components and embeds them between the upper and lower skins and the foam core. This integrated molding process eliminates the need for attaching an insulating layer to the surface of the liquid-cooled components, as well as the fasteners and seals required for subsequent assembly, significantly reducing manufacturing costs. Simultaneously, the production cycle is extremely short, making it suitable for the mass production needs of new energy vehicles; furthermore, integrated molding effectively ensures the long-term bonding reliability of dissimilar material interfaces, completely resolving the issue of delamination under long-term vibration or alternating hot and cold temperatures. Example 3

[0063] This embodiment provides a vehicle, preferably a pure electric passenger vehicle or commercial vehicle. The vehicle includes a chassis frame and a cold-plate embedded battery box structure installed at the bottom of the chassis frame. Specifically, the cold-plate embedded battery box structure is a sandwich composite material tray formed by high-pressure resin transfer molding as described in the previous embodiment.

[0064] In terms of assembly structure, the pallet is fixed to the longitudinal and transverse beams of the vehicle chassis via peripheral mounting flanges and high-strength bolts. Because the pallet adopts an integrated configuration that completely encapsulates aluminum liquid-cooled components, rigid structural foam, and steel reinforcement layers within the upper and lower skin layers of glass fiber reinforced composite material, its overall torsional stiffness is increased by 20% to 30% compared to traditional split-assembly aluminum alloy pallets. This highly integrated structure eliminates the mechanical connection gap between the liquid-cooled plate and the pallet base plate in traditional solutions, allowing the battery pack to participate in chassis load-bearing as a structural component when traveling on tortuous roads or cornering at high speeds, significantly reducing the dynamic deformation of the chassis.

[0065] Compared to the traditional aluminum alloy frame + external liquid cooling plate solution, the embedded tray used in this vehicle reduces the tray's weight by approximately 15% to 25% while maintaining the same or even higher impact protection strength. Based on a weight reduction of 15 kg to 25 kg per passenger vehicle tray, this can increase the overall vehicle range by approximately 2% to 3%. In terms of thermal management, by eliminating the PET insulating film on the surface of the liquid cooling components, heat from the bottom of the battery cells only needs to pass through the extremely thin and highly thermally conductive fiberglass skin to enter the cooling circuit, reducing interface thermal resistance by more than 40%. In high-power fast charging scenarios, the maximum temperature rise of the battery pack in this vehicle is also effectively reduced compared to traditional solutions, shortening charging waiting time and extending cell cycle life.

[0066] In terms of safety, thanks to the energy-absorbing effect of the steel reinforcement layer at the bottom and the rigid foam structure, the vehicle's external impact force is gradually dissipated by the sandwich structure during standard bottom scraping or pole impact tests, leaving the internal liquid cooling pipes intact. Even in the event of extreme fatigue cracking of the liquid cooling components, leaked coolant is firmly locked within the sandwich cavity composed of sealed foam and resin sealing, preventing it from overflowing into the high-voltage battery cell area above. This completely eliminates the risk of electrical short circuits caused by coolant, ensuring the safety of the occupants.

[0067] By integrating the aforementioned cold plate-embedded battery box structure, this vehicle not only achieves significant weight reduction and range improvement at the overall vehicle level, but also greatly optimizes thermal management efficiency with its insulation-free design, solving the problem of temperature rise during fast charging. At the same time, its unique embedded encapsulation structure achieves a high degree of unity between structural load-bearing capacity, physical protection, and failure safety (leakage prevention), providing new energy vehicles with a chassis system solution that integrates efficient heat dissipation, ultimate safety, and excellent structural efficiency.

[0068] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A cold-plate embedded battery box structure, characterized in that, It adopts a sandwich structure, which includes, from top to bottom: The upper skin layer is a fiber-reinforced composite material; The sandwich layer includes an embedded liquid cooling component, a lightweight core material, and a metal reinforcement layer; The lower skin layer is a fiber-reinforced composite material; The liquid cooling component, the lightweight core material, and the metal reinforcing layer are all wrapped between the upper skin layer and the lower skin layer, and are integrally formed with the upper skin layer and the lower skin layer.

2. The cold-plate embedded battery box structure according to claim 1, characterized in that, Within the sandwich layer, the liquid cooling component is disposed adjacent to the upper skin layer, the metal reinforcing layer is disposed adjacent to the lower skin layer, and the lightweight core material is disposed between the liquid cooling component and the metal reinforcing layer.

3. The cold-plate embedded battery box structure according to claim 1, characterized in that, The liquid cooling component is made of aluminum and has no insulating coating on its outer surface. The outer surface of the liquid cooling component has a conversion film layer formed by passivation treatment.

4. The cold plate embedded battery box structure according to claim 3, characterized in that, The conversion film layer is a micro-rough structure layer with micron- or nano-sized pores, and the conversion film layer forms a mechanically interlocked structure with the resin matrix in the upper skin layer.

5. The cold-plate embedded battery box structure according to claim 1, characterized in that, The lightweight core material is one or more of reinforced polyurethane foam, modified polyphenylene ether foam, or epoxy-modified polyamide foam; the metal reinforcing layer is a steel plate with a passivated surface.

6. The cold-plate embedded battery box structure according to claim 1, characterized in that, The reinforcing fibers in the upper skin layer and the lower skin layer are continuous glass fibers, and the upper skin layer contains a highly thermally conductive modified filler.

7. The cold plate embedded battery box structure according to claim 1, characterized in that, The liquid cooling component, the lightweight core material, the metal reinforcing layer, and the two skin layers are connected by resin injected through a high-pressure resin transfer molding process to fill the interface gaps and cure, forming a physical-chemical bonding interface without adhesives.

8. A method for preparing a cold-plate embedded battery box structure as described in any one of claims 1 to 7, characterized in that, Specifically, the following steps are included: S1: The liquid cooling component, the lightweight core material, and the metal reinforcing layer after surface passivation treatment are combined in a predetermined order and placed in a mold together with the fiber preform used to form the upper skin layer and the lower skin layer. S2: After closing the mold, high pressure is applied to inject resin into the mold to impregnate the fiber preform and fill the interface gaps between the fiber preform and the liquid cooling plate, and between the fiber preform and the steel plate; and the resin is controlled to not enter the gaps between the foam and the liquid cooling plate, and between the foam and the steel plate. S3: After the resin has cured, demold to obtain the cold plate embedded battery box structure.

9. The preparation method according to claim 8, characterized in that, In S2, the resin injection pressure is controlled between 10 bar and 60 bar, and the injection time is less than 1 minute; in S3, the resin is rapidly cured and molded within 2 to 5 minutes.

10. A vehicle, characterized in that, The device includes a vehicle body and a battery pack mounted on the vehicle body, the battery pack including the cold plate embedded battery box structure as described in any one of claims 1 to 7.

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