Flame-retardant composite material and application thereof, liquid cooling plate and battery box body

Abstract

The invention discloses a flame-retardant composite material and application thereof, a liquid cooling plate and a battery box body, and relates to the technical field of macromolecular flame-retardant materials. At least two resin materials are compounded, and the main matrix resin provides low water absorption and good toughness basis for the flame-retardant composite material; the auxiliary matrix resin can overcome the defects of the main matrix resin in rigidity and strength, and the overall mechanical property of the material is improved; the main matrix resin and the auxiliary matrix resin are subjected to an in-situ reaction in a melting processing process through the compatilizer, and a block or grafted copolymer is generated on a two-phase interface, so that low-water-absorption and high-strength fusion of the flame-retardant composite material is realized, and the main matrix resin and the auxiliary matrix resin form advantage complementation. Furthermore, a phosphorus-nitrogen synergistic flame retardant is adopted, so that a two-phase synergistic flame-retardant system of gas-phase flame retardance and condensed-phase flame retardance is realized, and the use safety of the battery shell can be ensured while the addition amount of the flame retardant is reduced.

Description

Technical Field

[0001] This invention relates to the field of polymer flame retardant materials technology, and more specifically, to a flame retardant composite material and its application, a liquid cooling plate, and a battery box. Background Technology

[0002] With the rapid development of the new energy vehicle industry, the performance requirements for the structural components of power batteries, as core components, are becoming increasingly stringent. Battery casings, such as the battery case and battery cover, are key structural components of the battery module, not only needing to provide mechanical support and protect the battery cells, but also needing to maintain stable physical properties under complex operating conditions.

[0003] With the increasing global awareness of environmental protection and the advancement of sustainable development strategies, bio-based materials have received widespread attention as alternatives to traditional petroleum-based materials. In the field of engineering plastics, nylon (polyamide) materials are widely used in the automotive, electronics, and other industries due to their excellent mechanical properties, heat resistance, and processing performance. Currently, some companies have successfully applied bio-based nylon materials to components such as battery casings for new energy vehicles, initially verifying the feasibility of bio-based materials in this field.

[0004] Compared to traditional petroleum-based engineering plastics, bio-based nylon materials offer advantages such as renewability and low carbon emissions. However, they still face numerous technical challenges in practical applications. For instance, bio-based nylon materials expand in volume after absorbing water, leading to dimensional drift (warping, deformation) under humid and hot cycling conditions, directly affecting the sealing performance and long-term reliability of battery packs. Furthermore, bio-based nylon materials have a low flame retardancy rating. While adding flame retardant materials can improve their flame retardancy, achieving high flame retardancy necessitates adding a significant amount of these materials. This results in decreased impact strength and significantly deteriorated melt flow properties, severely impacting the injection molding process window.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a flame-retardant composite material and its application, a liquid cooling plate, and a battery box.

[0007] This invention is implemented as follows: In a first aspect, the present invention provides a flame-retardant composite material, comprising, by mass percentage, 20-35% main matrix resin, 30-50% auxiliary matrix resin, 0.1-2% compatibilizer, 20-30% fiber reinforcing agent, 3-10% chemical toughening agent and 3-8% phosphorus-nitrogen synergistic flame retardant.

[0008] The main matrix resin includes at least one of polyamide 1010 (PA1010), polyamide 511 (PA511), polyamide 512 (PA512) and polyamide 1012 (PA1012).

[0009] The auxiliary matrix resin includes at least one of polyamide 56 (PA56), polyamide 66 (PA66), and polyamide 46 (PA46).

[0010] Secondly, the present invention provides a liquid cooling plate made of a flame-retardant composite material according to any of the foregoing embodiments.

[0011] Thirdly, the present invention provides a battery housing, including a base plate, a housing body, a liquid cooling pipe, and a liquid cooling plate as described in the foregoing embodiments.

[0012] The liquid cooling pipe is coiled and embedded in the liquid cooling plate, and the inlet and outlet of the liquid cooling pipe both extend out of the liquid cooling plate; the liquid cooling plate is sealed to the bottom of the housing body, and a bottom plate is provided on the side of the liquid cooling plate away from the housing body, and the bottom plate is sealed to the housing body; the inlet and outlet of the liquid cooling pipe both extend out of the housing body and / or the bottom plate.

[0013] Fourthly, the present invention provides an application of the flame-retardant composite material as described in any of the foregoing embodiments in any of the fields of batteries and their packaging structures, engines and fuel systems, fast charging devices for new energy vehicles, or high-voltage power transmission structures.

[0014] The present invention has the following beneficial effects: This invention provides a flame-retardant composite material and its applications, a liquid-cooled plate, and a battery casing. It employs a compounding of at least two resin materials. The main matrix resin is at least one of long-chain PA1010, PA511, PA512, and PA1012, providing a foundation for low water absorption and good toughness in the flame-retardant composite material. The auxiliary matrix resin is at least one of PA56, PA66, and PA46, compensating for the deficiencies in rigidity and strength of the main matrix resin and improving the overall mechanical properties of the material. Furthermore, a compatibilizer allows the main and auxiliary matrix resins to react in situ during melt processing, forming block or graft copolymers at the two-phase interface. This achieves a fusion of low water absorption and high strength in the flame-retardant composite material, resulting in a complementary advantage between the main and auxiliary matrix resins. Furthermore, the use of a phosphorus-nitrogen synergistic flame retardant achieves a two-phase synergistic flame-retardant system combining gas-phase and condensed-phase flame retardancy. This reduces the amount of flame retardant required while ensuring the safety of the battery casing, avoiding the negative impact of excessive flame retardant on the melt performance and mechanical properties of the flame-retardant composite material. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, 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 the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is an exploded view of the battery housing provided in an embodiment of the present invention; Figure 2 A cross-sectional view showing the distribution of the liquid cooling plate and liquid cooling pipes provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure after the liquid cooling plate and the housing body are installed, as provided in an embodiment of the present invention. Figure 4 This is a side view of the structure after the liquid cooling plate and the housing body are installed, as provided in an embodiment of the present invention. Figure 5 This is a schematic diagram of the battery housing provided in an embodiment of the present invention; Figure 6 This is a structural side view of the battery box provided in an embodiment of the present invention.

[0017] Explanation of main component symbols: 100-Battery box; 110-Box body; 111-Side panel; 112-Internal partition; 120-Liquid cooling plate; 121-Connection area; 130-Liquid cooling pipe; 140-Bottom plate. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0019] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0020] With the increasing global awareness of environmental protection and the advancement of sustainable development strategies, bio-based materials have received widespread attention as alternatives to traditional petroleum-based materials. However, the inventors have discovered that current bio-based nylon materials face the following problems when replacing traditional petroleum-based materials in power batteries: First, single bio-based nylon materials may have excessive water absorption, causing them to easily absorb moisture and expand in humid environments after being manufactured into components, leading to dimensional drift (warping, deformation) and affecting the sealing accuracy and long-term reliability of the battery pack; or their mechanical properties may be insufficient to support the high load scenarios of the power battery. Furthermore, due to the macromolecular characteristics of bio-based nylon materials, the development of composite bio-based nylon materials is difficult, with poor compatibility, and some composite bio-based nylon materials even exhibit performance degradation.

[0021] Secondly, bio-based nylon materials have insufficient notched impact strength at low temperatures, making it difficult to meet the usage requirements in cold regions.

[0022] Furthermore, bio-based nylon materials have a low flame retardancy rating, making it difficult to meet UL94 V-0 or relevant standards for new energy batteries. Although its flame retardancy can be improved by adding flame retardant materials, a large amount of these materials must be added to ensure high flame retardancy. This leads to a decrease in the impact strength of bio-based nylon materials and a significant deterioration in melt flow properties, severely affecting the injection molding process window.

[0023] To solve any of the above problems, the inventors provide the following solution: In a first aspect, the present invention provides a flame-retardant composite material, comprising, by mass percentage, 20-35% main matrix resin, 30-50% auxiliary matrix resin, 0.1-2% compatibilizer, 20-30% fiber reinforcing agent, 3-10% chemical toughening agent and 3-8% phosphorus-nitrogen synergistic flame retardant.

[0024] The main matrix resin is a long-chain nylon with relatively low hydrophilicity, including at least one of PA1010, PA511, PA512, and PA1012. PA1010 is preferred. PA1010, as the main matrix resin, is a long-chain nylon with a low density of amide groups (-CONH-) in its molecular structure. Amide groups are hydrophilic groups; the lower their density, the lower the overall water absorption rate of the material. Therefore, by using PA1010 as the main matrix resin, this invention can reduce the material's hygroscopic tendency at the molecular level, significantly improve dimensional stability, and solve the problem of warping and deformation caused by high water absorption in the prior art.

[0025] In addition, PA1010 has a certain degree of toughness, but its rigidity and strength are relatively insufficient, and it needs to be compensated by other components. Therefore, the flame retardant composite material of the present invention is also compounded with auxiliary matrix resin and main matrix resin to form the macromolecular structure of flame retardant composite material.

[0026] Specifically, the auxiliary matrix resin has high rigidity and strength, including at least one of PA56, PA66 and PA46; preferably PA56.

[0027] That is, in a preferred embodiment of the present invention, the main matrix resin is PA1010 and the auxiliary matrix resin is PA56.

[0028] It should be noted that the main matrix resin and auxiliary matrix resin are not determined by their addition amount, but by their distribution in the flame-retardant composite material. PA1010 is the main polymer constituting the continuous phase in the flame-retardant composite material and is also the resin that bears the main functional properties. PA56 has a strong rigid structure, which can effectively improve the tensile strength and flexural strength of the composite material. Using PA56 as an auxiliary matrix resin can compensate for the deficiencies of PA1010 in rigidity and strength, and improve the overall mechanical properties of the material. However, PA56 has a high water absorption rate, and PA56 and PA1010 have different chemical structures. Direct blending can easily lead to phase separation and poor interfacial bonding, affecting the uniformity and mechanical properties of the material. Therefore, how to achieve structural compatibility and complementary advantages between the two is one of the problems that urgently needs to be solved in this field.

[0029] Therefore, this application incorporates a compatibilizer into the flame-retardant composite material. In optional embodiments, the compatibilizer includes at least one of a multifunctional epoxy polymer and an oxazoline polymer, preferably a multifunctional epoxy polymer.

[0030] In an optional embodiment, the multifunctional epoxy polymer includes at least one of phenoxy resin and epoxy-functionalized acrylate polymer.

[0031] By selecting the aforementioned compatibilizers, PA1010 and PA56 achieve reactive compatibility under the action of the compatibilizers, preventing performance degradation caused by phase separation. The multifunctional epoxy polymer can chemically react with the terminal amino (–NH2) or carboxyl (–COOH) groups of the two nylons during melt blending, forming block copolymers in situ. These copolymers act as molecular bridges, enhancing the interfacial adhesion between the two phases and achieving stable blending. This ensures that the composite resin material can leverage the low water absorption advantage of PA1010 while exhibiting the high strength of PA56, controlling the overall water absorption rate while maintaining a certain rigidity of the flame-retardant composite material.

[0032] Furthermore, to further improve the toughness of the flame-retardant composite material at low temperatures, a chemical toughening agent is added in this invention. In optional embodiments, the chemical toughening agent includes at least one of maleic anhydride-grafted polyolefin elastomer (POE-g-MAH) and core-shell elastomer; wherein, the maleic anhydride-grafted polyolefin elastomer (POE-g-MAH) may be, for example, maleic anhydride-grafted ethylene-vinyl acetate copolymer (EVA-g-MAH), and the core-shell elastomer may be, for example, methyl methacrylate-butadiene-styrene copolymer (MBS); preferably, the chemical toughening agent is maleic anhydride-grafted polyolefin elastomer (POE-g-MAH).

[0033] In maleic anhydride-grafted polyolefin elastomer (POE-g-MAH), the maleic anhydride (MAH) functional groups can chemically react with the terminal amino groups of nylon to form covalent bonds, allowing the elastomer phase to be uniformly dispersed in the nylon matrix without aggregation or precipitation. Under external impact, the elastomer particles can induce energy dissipation mechanisms such as crazes and shear bands, absorbing a large amount of impact energy and preventing rapid crack propagation. Especially at temperatures as low as -40℃, it maintains good toughening effects, solving the problem of low-temperature brittleness in existing materials.

[0034] Furthermore, the present invention also adds fiber reinforcing agents to help enhance the mechanical properties of flame-retardant composite materials.

[0035] In an optional embodiment, the fiber reinforcing agent includes at least one selected from basalt fiber, glass fiber, and aramid fiber. The fiber reinforcing agent can improve the impact resistance and stress cracking resistance of the flame-retardant composite material.

[0036] Preferably, the fiber reinforcement is composed of chopped basalt fiber and glass fiber in a mass ratio of (1:1) to (1:2). Basalt fiber has a high elongation at break and good energy absorption capacity, effectively preventing crack propagation and improving the notched impact strength of the material under impact loads, especially at low temperatures. Glass fiber has high tensile strength and elastic modulus, significantly improving the rigidity, dimensional stability, and heat resistance of the composite material. While its use alone may increase brittleness, its combination with the tougher basalt fiber achieves a balanced optimization of strength and toughness, resulting in a "hybrid effect" between the chopped basalt fiber and glass fiber. This synergistic effect of different fiber properties balances the material's strength, modulus, and toughness, particularly beneficial for improving the tensile strength of localized stress areas such as the bolt hole area of ​​the battery cover.

[0037] Furthermore, this invention solves the compatibility problem of composite bio-based nylon materials and the complementary advantages of various bio-based nylon materials. So how can we further improve the flame retardant properties of bio-based nylon materials without affecting the mechanical properties of composite bio-based nylon materials? This invention solves this problem by adding a phosphorus-nitrogen synergistic flame retardant to the flame retardant composite material.

[0038] In an optional embodiment, the phosphorus-nitrogen synergistic flame retardant comprises a DOPO derivative and melamine polyphosphate in a mass ratio of (1:1) to (1:1.5). The DOPO derivative is a derivative of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

[0039] The DOPO derivative includes at least one of DOPO-HQ, DOPO-ITA, or DOPO-PN. Preferably, the DOPO derivative is DOPO-ITA.

[0040] DOPO derivatives, as phosphorus-based flame retardant components, participate in the construction of efficient halogen-free flame retardant systems. DOPO derivatives are phosphorus-containing organic compounds that can play a role in capturing gaseous free radicals during combustion (such as capturing H· and OH· free radicals), thus inhibiting flame propagation. Simultaneously, DOPO derivatives can also promote char formation in the condensed phase, forming a dense char layer that isolates oxygen and heat transfer.

[0041] Melamine polyphosphate (MPP), as a key component in the nitrogen-phosphorus synergistic flame retardant system, provides a phosphorus source and foaming and charring functions. When heated, MPP decomposes to produce non-flammable gases (such as NH3, N2, and H2O), thereby diluting the concentration of flammable gases and exerting a gas-phase flame retardant effect. At the same time, MPP releases phosphoric acid substances, catalyzing the dehydration and carbonization of the nylon matrix to form an intumescent char layer, thus exerting a condensed-phase flame retardant effect. Furthermore, MPP can be combined with DOPO derivatives in a specific ratio to form a "phosphorus-nitrogen synergistic" mechanism, which improves flame retardant performance, reduces the total amount of flame retardant, and mitigates the damage to the mechanical properties of flame retardant composite materials caused by the addition of flame retardants. This allows the flame retardant composite material to achieve a UL94 V-0 (1.6mm) rating with a lower amount of flame retardant added.

[0042] In an optional embodiment, at least one of the following is added, based on the mass percentage of the flame-retardant composite material: 0.1-1% antioxidant, 0.1-1% lubricant, and 0.5-3% silane coupling agent modified nano-silica.

[0043] The antioxidants, lubricants, and silane coupling agents used to modify nano-silica can all be commercially available conventional materials, and this invention does not impose any restrictions on them. For example, hindered phenolic antioxidants can be used as antioxidants; and at least one of calcium stearate, zinc stearate, or ethylene bis-stearamide can be used as lubricant.

[0044] Preferably, the components in the flame-retardant composite material, by mass percentage, include PA1010: 20-35%, PA56: 30-50%, compatibilizer: 0.1-2%, fiber reinforcement: 20-30%, chemical toughening agent: 3-10%, phosphorus-nitrogen synergistic flame retardant: 3-8%, antioxidant: 0.1-1%, lubricant: 0.1-1%, and silane coupling agent modified nano-silica: 0.5-3%.

[0045] In an optional embodiment, the present invention also provides a method for preparing a flame-retardant composite material according to any of the foregoing embodiments, comprising weighing each raw material in proportion and mixing them evenly.

[0046] In an optional implementation, depending on the application scenario of the flame-retardant composite material, the composite melt obtained by weighing and mixing the raw materials in proportion can be molded by injection molding, mold forming, or other conventional molding methods.

[0047] With the rapid development of electric vehicles and large-scale energy storage systems, power battery systems are constantly evolving towards higher energy density, higher charge and discharge rates, and higher integration efficiency. This trend presents more severe and complex technical challenges to battery thermal management. As the core support and protection structure of the battery module, the battery casing not only needs to bear multiple functions such as mechanical load-bearing, impact resistance, and sealing protection, but also needs to integrate efficient temperature management functions to ensure that the cells operate within a safe and suitable temperature range, effectively delay the risk of thermal runaway, and ensure the reliability and safety of the system throughout its entire life cycle.

[0048] The flame-retardant composite material provided by this invention can be effectively applied in power batteries. For specific application methods, please refer to the following content.

[0049] Secondly, the present invention provides a liquid cooling plate made of a flame-retardant composite material according to any of the foregoing embodiments.

[0050] In an optional embodiment, the liquid cooling plate is prepared by melting and mixing the raw materials of the flame-retardant composite material in proportion, and then injection molding.

[0051] Since the flame-retardant composite material provided by this invention is a polymer material with strong comprehensive performance, its characteristics of light weight, corrosion resistance and high degree of design freedom show great potential in the integration of lightweight materials and cooling systems.

[0052] Thirdly, please refer to Figure 1 The present invention provides a battery housing 100, including a base plate 140, a housing body 110, a liquid cooling pipe 130 and a liquid cooling plate 120 as described in the above embodiments.

[0053] Please refer to Figure 2 The liquid cooling pipe 130 is coiled and embedded within the liquid cooling plate 120, with both the inlet and outlet of the liquid cooling pipe 130 extending outside the liquid cooling plate 120. Please refer to... Figure 3 and Figure 4 The liquid cooling plate 120 is sealed to the bottom of the housing body 110. Please refer to... Figure 5 and Figure 6 A base plate 140 is provided on the side of the liquid cooling plate 120 away from the housing body 110, and the base plate 140 is fixedly connected to the liquid cooling plate 120; the inlet and outlet of the liquid cooling pipe 130 extend out of the housing body 110 and / or the base plate 140 to ensure that the liquid cooling pipe 130 can be connected to the external fluid transport pipeline.

[0054] This invention applies the liquid cooling plate 120 made of the flame-retardant composite material described in the aforementioned embodiments to the battery case 100. The battery case 100 has a built-in liquid cooling plate 120, and liquid cooling pipes 130 are directly embedded inside the liquid cooling plate 120, forming a cooling channel network directly inside the liquid cooling plate 120. This embedded design eliminates the interfacial contact thermal resistance between the traditional metal cold plate and the bottom plate 140 of the case, improving heat conduction efficiency. At the same time, the application of flame-retardant composite material can significantly reduce the weight of the case, improve battery bulging, and has excellent chemical corrosion resistance and insulation properties.

[0055] Furthermore, existing battery enclosures 100 typically use sheet metal such as aluminum alloy and steel for their enclosure body 110. These enclosures rely on stamping and welding processes to divide the interior into multiple spaces, resulting in numerous processing and assembly steps during production, leading to long production cycles and high costs. Welding operations can easily cause structural deformation and residual stress, affecting dimensional accuracy and sealing integrity. This not only increases the risk of coolant leakage but also enhances the complexity of the assembly process.

[0056] In an optional embodiment, the side panels 111 and the internal partitions 112 of the housing body 110 are integrally formed. By manufacturing an integrally formed housing body 110, the present invention completely avoids the welding process between the battery housing 100 and the vertical partitions in traditional manufacturing, significantly simplifying the production process, improving heat dissipation efficiency and the consistency and airtightness of the overall structure, while also improving the space utilization of the battery pack.

[0057] In an optional embodiment, the housing body 110 is divided into at least two small areas by side panels 111 and internal partitions 112, each small area being used to accommodate at least one of a battery, a high-voltage box, and a battery management system.

[0058] Furthermore, the flame-retardant composite material provided by this invention has excellent strength, low water absorption, and excellent flame-retardant properties. This structure can adapt to volume changes during battery charging and discharging to a certain extent, thereby effectively alleviating the battery bulging problem and improving the safety and reliability of the system in long-term use.

[0059] Since the liquid cooling pipe 130 is embedded in the liquid cooling plate 120, during the molding process of the liquid cooling plate 120, the liquid cooling pipe 130 can be pre-embedded in the mold and integrally molded with the uniformly molten flame-retardant composite material.

[0060] In an optional embodiment, the liquid cooling pipe 130 is wound in an S-shape in the horizontal direction of the liquid cooling plate 120. This arrangement of the liquid cooling pipe 130 can further ensure the temperature uniformity of the liquid cooling plate 120 in the horizontal direction and reduce the risk of battery bulging.

[0061] In optional embodiments, the inlet and outlet of the liquid cooling pipe 130 may both extend out of the outer surface of the housing body 110; or the inlet and outlet of the liquid cooling pipe 130 may both extend out of the outer surface of the base plate 140; or the inlet of the liquid cooling pipe 130 may extend out of the outer surface of the housing body 110 and the outlet of the liquid cooling pipe 130 may extend out of the outer surface of the base plate 140; or the inlet of the liquid cooling pipe 130 may extend out of the outer surface of the base plate 140 and the outlet of the liquid cooling pipe 130 may extend out of the outer surface of the housing body 110.

[0062] In an optional implementation, the inlet and outlet of the liquid cooling pipe 130 can be interchanged, as long as the two ends of the liquid cooling pipe 130 are an outlet and an inlet, respectively.

[0063] In an optional embodiment, the base plate 140 is made of at least one of aluminum and stainless steel to enhance the lightweight advantage of the battery housing 100 of the present invention. In other embodiments, if the application scenario does not require lightweighting, a steel base plate 140 may also be used.

[0064] In an optional embodiment, the bottom plate 140 is approximately the same size as the bottom of the box body 110 to ensure that the bottom plate 140 and the box body 110 form a structurally regular whole.

[0065] In an optional embodiment, the base plate 140 and the housing body 110 can be connected by a connector, which can be at least two of screws, bolts and nuts.

[0066] In an optional embodiment, the base plate 140 is fixedly connected to the liquid cooling plate 120, for example, by bonding, to ensure the structural stability of the battery box 100.

[0067] In an optional embodiment, the liquid cooling plate 120 is horizontal with the bottom of the housing body 110 to reduce the volume of the battery box. Preferably, the shape of the liquid cooling plate 120 is the same as the bottom shape of the housing body 110. When the bottom plate 140 is fixed to the housing body 110 by a connector, in order to facilitate the connection between the bottom plate 140 and the housing body 110, a connection area 121 can be pre-formed in the liquid cooling plate 120 during the forming process to ensure that the connector can pass through the liquid cooling plate 120 to connect and fix the bottom plate 140 and the housing body 110.

[0068] In an optional embodiment, the liquid cooling plate 120 and the bottom of the housing body 110 can be connected by threads, and thermal conductive gel can be used for sealing connection to ensure the structural stability of the battery housing 100.

[0069] Fourthly, the present invention provides an application of the flame-retardant composite material as described in any of the foregoing embodiments in any of the fields of batteries and their packaging structures, engines and fuel systems, fast charging devices for new energy vehicles, or high-voltage power transmission structures.

[0070] In an optional embodiment, the application of flame-retardant composite materials in the field of batteries and their packaging structures includes using flame-retardant composite materials to prepare battery cases or battery covers.

[0071] And / or, the application of flame-retardant composite materials in engine and fuel systems includes using flame-retardant composite materials to prepare engine housings or engine transmission structures.

[0072] And / or, the application of flame-retardant composite materials in fast charging devices or high-voltage power transmission structures for new energy vehicles includes using flame-retardant composite materials to prepare fast charging interface modules and high-voltage connectors, etc.

[0073] The raw materials used in the following examples and comparative examples were sourced as follows: PA1010 was purchased from Suzhou Akoma, brand name: TZM 30BK; PA56 was purchased from Kaisai Biotechnology, brand name: E-1273; phenoxy resin was purchased from Jitsugyo Chemical, brand name: YP-50; chopped basalt fiber was purchased from Zhejiang Shijin Basalt Fiber Co., Ltd.; glass fiber was purchased from Jushi Group, model ECS301CL; POE-g-MAH was purchased from Jiayirong (Shanghai) Chemical, brand name: CMG5805-L; DOPO-ITA was purchased from Hanfeng Technology; melamine polyphosphate was purchased from BASF (China) Co., Ltd., brand name: Melapur® 200 / 70; silane coupling agent modified nano-SiO2 was purchased from Nanjing Qizheng Chemical Co., Ltd.; antioxidant was purchased from Songwon's antioxidant 1010, brand name: SONGNOX® 1010; calcium stearate was purchased from Hangzhou Zanyu Oils Technology Co., Ltd.

[0074] Example 1 This embodiment provides a flame-retardant composite material, the components of which, by mass percentage, include PA1010: 26.4%, PA56: 40.6%, phenoxy resin: 1.0%, chopped basalt fiber: 10.2%, glass fiber: 10.2%, POE-g-MAH: 5.1%, DOPO-ITA: 2.0%, melamine polyphosphate: 3.0%, silane coupling agent modified nano-SiO2: 1.0%, antioxidant 1010: 0.3%, and calcium stearate: 0.2%.

[0075] Example 2 This embodiment provides a flame-retardant composite material, the components of which, by mass percentage, include PA1010: 22.0%, PA56: 45.0%, phenoxy resin: 1.5%, chopped basalt fiber: 7.0%, glass fiber: 14.0%, POE-g-MAH: 4.0%, DOPO-ITA: 2.0%, melamine polyphosphate: 3.0%, silane coupling agent modified nano-SiO2: 1.0%, antioxidant 1010: 0.2%, and calcium stearate: 0.3%.

[0076] Example 3 This embodiment provides a flame-retardant composite material, the components of which, by mass percentage, include PA1010: 28%, PA56: 38%, phenoxy resin: 1.2%, chopped basalt fiber: 18%, glass fiber: 0%, POE-g-MAH: 8.0%, DOPO-ITA: 2.5%, melamine polyphosphate: 2.5%, silane coupling agent modified nano-SiO2: 1.3%, antioxidant 1010: 0.3%, and calcium stearate: 0.2%.

[0077] Example 4 like Figure 1 As shown, this embodiment provides a battery housing 100, including a housing body 110, a liquid cooling plate 120, a liquid cooling pipe 130, and a base plate 140. The liquid cooling plate 120 is made of the flame-retardant composite material provided in Embodiment 1 of this invention.

[0078] Please refer to Figure 2 In this embodiment, the liquid cooling pipe 130 is embedded in the liquid cooling plate 120. Therefore, during the molding process of the liquid cooling plate 120, the liquid cooling pipe 130 can be pre-embedded in the mold and integrally molded with the uniformly molten flame-retardant composite material.

[0079] In this embodiment, the liquid cooling pipe 130 is arranged in an S-shape, winding back and forth in the horizontal direction of the liquid cooling plate 120, and both the inlet and outlet of the liquid cooling pipe 130 extend outside the liquid cooling plate 120. The inlet and outlet of the liquid cooling pipe 130 can be interchanged, as long as each end of the liquid cooling pipe 130 has an outlet and an inlet respectively.

[0080] Please refer to Figure 1 In this embodiment, the side plate 111 and the internal partition 112 of the housing body 110 are integrally formed. The housing body 110 is divided into 10 small areas by the side plate 111 and the internal partition 112, which can be used to accommodate at least one of the following: battery, high voltage box and battery management system.

[0081] Please refer to Figure 3 and Figure 4The liquid cooling plate 120 is threaded to the bottom of the housing body 110 and sealed with thermally conductive gel. The bottom of the liquid cooling plate 120 and the housing body 110 are horizontal to reduce the volume of the battery box. In addition, in this embodiment, to facilitate the connection between the bottom plate 140 and the housing body 110, a connection area 121 can be pre-formed during the molding process of the liquid cooling plate 120 to ensure that the connector can pass through the liquid cooling plate 120 and connect and fix the bottom plate 140 to the housing body 110.

[0082] Please refer to Figure 5 and Figure 6 A base plate 140 is provided on the side of the liquid cooling plate 120 away from the housing body 110. The bottom size of the base plate 140 is similar to that of the housing body 110 to ensure that the base plate 140 is tightly connected to the housing body 110. In this embodiment, the base plate 140 is connected and fixed to the housing body 110 by screws and nuts, or the base plate 140 is bonded and fixed to the liquid cooling plate 120. The inlet and outlet of the liquid cooling pipe 130 both extend out of the outer surface of the housing body 110.

[0083] Furthermore, in this embodiment, the base plate 140 is an aluminum base plate 140 to enhance the lightweight advantage of the battery box 100 of the present invention.

[0084] Comparative Example 1 This comparative example provides a flame-retardant composite material, the components of which, by mass percentage, include PA1010: 67.0%, phenoxy resin: 1.0%, chopped basalt fiber: 10.2%, glass fiber: 10.2%, POE-g-MAH: 5.1%, DOPO-ITA: 2.0%, melamine polyphosphate: 3.0%, silane coupling agent modified nano-SiO2: 1.0%, antioxidant 1010: 0.3%, and calcium stearate: 0.2%.

[0085] Comparative Example 2 This comparative example provides a flame-retardant composite material, the components of which, by mass percentage, include PA56: 67.0%, phenoxy resin: 1.0%, chopped basalt fiber: 10.2%, glass fiber: 10.2%, POE-g-MAH: 5.1%, DOPO-ITA: 2.0%, melamine polyphosphate: 3.0%, silane coupling agent modified nano-SiO2: 1.0%, antioxidant 1010: 0.3%, and calcium stearate: 0.2%.

[0086] Comparative Example 3 This comparative example provides a flame-retardant composite material, the components of which, by mass percentage, include PA1010: 30.6%, PA56: 35.4%, phenoxy resin: 1.0%, chopped basalt fiber: 10.2%, glass fiber: 10.2%, POE-g-MAH: 5.1%, DOPO-ITA: 2.0%, melamine polyphosphate: 3.0%, silane coupling agent modified nano-SiO2: 1.0%, antioxidant 1010: 0.3%, and calcium stearate: 0.2%.

[0087] Comparative Example 4 This comparative example provides a flame-retardant composite material, the components of which, by mass percentage, include PA1010: 16%, PA56: 51%, phenoxy resin: 1.0%, chopped basalt fiber: 10.2%, glass fiber: 10.2%, POE-g-MAH: 5.1%, DOPO-ITA: 2.0%, melamine polyphosphate: 3.0%, silane coupling agent modified nano-SiO2: 1.0%, antioxidant 1010: 0.3%, and calcium stearate: 0.2%.

[0088] Comparative Example 5 This comparative example provides a flame-retardant composite material, the components of which, by mass percentage, include PA1010: 26%, PA56: 41%, phenoxy resin: 1.0%, glass fiber: 20.4%, POE-g-MAH: 5.1%, DOPO-ITA: 2.0%, melamine polyphosphate: 3.0%, silane coupling agent modified nano-SiO2: 1.0%, antioxidant 1010: 0.3%, and calcium stearate: 0.2%.

[0089] Comparative Example 6 This comparative example provides a flame-retardant composite material, the components of which, by mass percentage, include PA1010: 26%, PA56: 41%, phenoxy resin: 1.0%, chopped basalt fiber: 20.4%, POE-g-MAH: 5.1%, DOPO-ITA: 2.0%, melamine polyphosphate: 3.0%, silane coupling agent modified nano-SiO2: 1.0%, antioxidant 1010: 0.3%, and calcium stearate: 0.2%.

[0090] Comparative Example 7 This comparative example provides a flame-retardant composite material, the components of which, by mass percentage, include PA1010: 26%, PA56: 41%, phenoxy resin: 1.0%, chopped basalt fiber: 5.1%, glass fiber: 15.3%, POE-g-MAH: 5.1%, DOPO-ITA: 2.0%, melamine polyphosphate: 3.0%, silane coupling agent modified nano-SiO2: 1.0%, antioxidant 1010: 0.3%, and calcium stearate: 0.2%.

[0091] Comparative Example 8 This comparative example provides a flame-retardant composite material, the components of which, by mass percentage, include PA1010: 27%, PA56: 43%, phenoxy resin: 1.2%, chopped basalt fiber: 10.8%, glass fiber: 10.8%, DOPO-ITA: 2.2%, melamine polyphosphate: 3.2%, silane coupling agent modified nano-SiO2: 1.1%, antioxidant 1010: 0.4%, and calcium stearate: 0.3%.

[0092] Comparative Example 9 This embodiment provides a flame-retardant composite material, the components of which, by mass percentage, include PA1010: 27%, PA56: 43.1%, phenoxy resin: 1.0%, chopped basalt fiber: 10.7%, glass fiber: 10.7%, POE-g-MAH: 1.0%, DOPO-ITA: 2.0%, melamine polyphosphate: 3.0%, silane coupling agent modified nano-SiO2: 1.0%, antioxidant 1010: 0.3%, and calcium stearate: 0.2%.

[0093] Comparative Example 10 This embodiment provides a flame-retardant composite material, the components of which, by mass percentage, include PA1010: 23.6%, PA56: 36.5%, phenoxy resin: 1.0%, chopped basalt fiber: 10.2%, glass fiber: 10.2%, POE-g-MAH: 12%, DOPO-ITA: 2.0%, melamine polyphosphate: 3.0%, silane coupling agent modified nano-SiO2: 1.0%, antioxidant 1010: 0.3%, and calcium stearate: 0.2%.

[0094] Comparative Example 11 This comparative example provides a flame-retardant composite material, the components of which, by mass percentage, include PA1010: 27.2%, PA56: 43.2%, phenoxy resin: 1.1%, chopped basalt fiber: 10.8%, glass fiber: 10.8%, POE-g-MAH: 5.3%, silane coupling agent modified nano-SiO2: 1.1%, antioxidant 1010: 0.3%, and calcium stearate: 0.2%.

[0095] Comparative Example 12 This comparative example provides a flame-retardant composite material, the components of which, by mass percentage, include PA1010: 26%, PA56: 41%, phenoxy resin: 1.0%, chopped basalt fiber: 10.2%, glass fiber: 10.2%, POE-g-MAH: 5.1%, DOPO-ITA: 5.0%, silane coupling agent modified nano-SiO2: 1.0%, antioxidant 1010: 0.3%, and calcium stearate: 0.2%.

[0096] Comparative Example 13 This comparative example provides a flame-retardant composite material, the components of which, by mass percentage, include PA1010: 26%, PA56: 41%, phenoxy resin: 1.0%, chopped basalt fiber: 10.2%, glass fiber: 10.2%, POE-g-MAH: 5.1%, melamine polyphosphate: 5.0%, silane coupling agent modified nano-SiO2: 1.0%, antioxidant 1010: 0.3%, and calcium stearate: 0.2%.

[0097] Experimental Example 1 The flame-retardant composite materials provided in Examples 1-3 and Comparative Examples 1-13 were melt-blended and granulated, and then prepared into specimens that met various performance test standards by injection molding machine. Their performance was tested according to the corresponding standards, and the results are shown in Table 1.

[0098] The water absorption rate was determined according to ISO 62 standard, by immersing the sample in water at 23°C for 24 hours and measuring the weight change.

[0099] The low-temperature notched impact strength is tested at -40°C according to ISO 179-1 standard.

[0100] The flame retardancy rating is based on the UL94 standard, and the vertical flammability rating of a 1.6mm thick sample is tested.

[0101] Tensile strength was tested according to ISO 527 standard.

[0102] Bending strength was tested according to ISO 178 standard.

[0103] Table 1 Performance of Flame-Retardant Composite Materials

[0104] As shown in Table 1, the flame-retardant composite material provided in this embodiment of the invention has a low water absorption rate and is not prone to water absorption and swelling during use. When it is made into battery components, the battery is not prone to bulging, thus ensuring the sealing accuracy and long-term reliability of the battery.

[0105] Example 1, representing the optimized formulation provided by this invention, exhibits excellent and balanced water absorption, low-temperature toughness, flame retardancy rating, and mechanical strength. This demonstrates that the formulation successfully achieves comprehensive performance of low water absorption, high toughness, high strength, and reliable flame retardancy, fully meeting the stringent service requirements of battery housings. Example 2, by increasing the ratio of PA56 to glass fiber, further enhances tensile and flexural strength, highlighting its formulation advantages in pursuing ultimate rigidity. Although its low-temperature toughness and water resistance are slightly sacrificed, it still maintains a V-0 flame retardancy rating, making it suitable for scenarios with extremely high structural strength requirements. Example 3, by increasing the content of PA1010, basalt fiber, and POE-g-MAH, demonstrates excellent low-temperature toughness and the lowest water absorption. Its impact resistance is the most outstanding, fully reflecting the formulation's targeted design for coping with the challenges of cold and humid environments.

[0106] Comparative Example 1, lacking PA56, resulted in components with low low-temperature notched impact strength, tensile strength, and flexural strength, failing to meet the service requirements of complex operating conditions. Comparative Example 2, lacking PA1010, exhibited significantly increased water absorption, leading to moisture absorption and bulging during battery cycling, affecting battery reliability. It also lacked low-temperature toughness, and its flame retardant rating dropped to V-1. Comparative Example 3 increased the proportion of PA1010 while reducing the amount of PA56, resulting in decreased material rigidity. Both tensile and flexural strengths were lower than in Example 1, failing to achieve optimal strength. Comparative Example 4 further increased the proportion of PA56, achieving higher strength, but its water absorption increased sharply, low-temperature impact performance deteriorated, and its flame retardant rating dropped to V-1, demonstrating a severe imbalance in the resin ratio.

[0107] Comparative Example 5, using only glass fiber, achieved the highest flexural strength but also exhibited the worst low-temperature impact toughness, displaying brittleness and a decreased flame retardancy rating, demonstrating that glass fiber alone cannot achieve a balance between toughness and flame retardancy. Comparative Example 6, using only basalt fiber, showed superior impact toughness compared to the pure glass fiber solution, but its rigidity and strength were not optimal, highlighting the limitations of using only basalt fiber. Comparative Example 7, with its excessively low basalt fiber content and high glass fiber content, resulted in significantly lower impact toughness than Example 1 and a decreased flame retardancy rating, demonstrating the crucial role of the fiber blending ratio in achieving performance balance in this invention.

[0108] Comparative Example 8, without the addition of POE-g-MAH, exhibited a sharp deterioration in low-temperature toughness and a minimum impact strength, failing to meet the multi-scenario application requirements of batteries. Comparative Example 9, with an excessively low POE-g-MAH content, showed insufficient toughening effect, still exhibiting poor low-temperature impact strength, and a flame retardant rating dropping to V-1. Comparative Example 10, with an excessively high POE-g-MAH content, severely compromised the material's rigidity and strength, leading to a surge in water absorption and a flame retardant rating dropping to V-2, demonstrating that the toughening agent content must be strictly controlled within the optimal range. Comparative Example 11, without any flame retardant, exhibited relatively good toughness and mechanical properties, but completely burned during the flame retardant test, failing to pass any rating and failing to meet the flame retardant safety requirements for battery use. Comparative Examples 12 and 13, each using a single flame retardant, maintained V-0 flame retardancy, but their mechanical properties and low-temperature toughness declined, demonstrating the superiority of the phosphorus-nitrogen synergistic flame retardant system in this application in maintaining the overall performance of the material while ensuring flame retardant effects.

[0109] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A flame retardant composite material, characterized by, by mass percentage, including main base resin 20-35%, auxiliary base resin 30-50%, compatibilizer 0.1-2%, fiber reinforcing agent 20-30%, chemical toughening agent 3-10%, and phosphorus-nitrogen synergistic flame retardant 3-8%; The main base resin includes at least one of PA1010, PA511, PA512 and PA1012; The auxiliary base resin includes at least one of PA56, PA66 and PA46.

2. The flame retardant composite of claim 1, wherein, The phosphorus-nitrogen synergistic flame retardant includes DOPO derivative and melamine polyphosphate in a mass ratio of (1:1) to (1:1.5); The DOPO derivative includes at least one of DOPO-HQ, DOPO-ITA or DOPO-PN.

3. The flame retardant composite of claim 1, wherein, Each raw material satisfies at least one of the following characteristics: Characteristic 1: the main base resin is PA1010, and the auxiliary base resin is PA56; Characteristic 2: the chemical toughening agent includes at least one of maleic anhydride grafted polyolefin elastomer and core-shell structure elastomer; Characteristic 3: the compatibilizer includes at least one of multifunctional epoxy polymer and oxazoline polymer; The multifunctional epoxy polymer includes at least one of phenoxy resin and epoxy functionalized acrylate polymer.

4. The flame retardant composite of claim 1, wherein, The fiber reinforcing agent includes at least one of basalt fiber, glass fiber and aramid fiber; And / or, the fiber reinforcing agent is composed of short basalt fiber and glass fiber in a mass ratio of (1:1) to (1:2).

5. The flame retardant composite of claim 1, wherein, Further including at least one of antioxidant 0.1-1%, lubricant 0.1-1% and silane coupling agent modified nano silicon dioxide 0.5-3% by mass percentage of the flame-retardant composite.

6. A liquid cold plate comprising: Prepared from the flame-retardant composite of any one of claims 1-5.

7. A battery case characterized by comprising: Including a bottom plate, a box body, a liquid cooling pipe and a liquid cooling plate as claimed in claim 6; The liquid cooling pipe is coiled and embedded in the liquid cooling plate, and the inlet and outlet of the liquid cooling pipe both extend out of the liquid cooling plate; the liquid cooling plate is sealingly connected to the bottom of the box body, and the side of the liquid cooling plate away from the box body is provided with the bottom plate, which is fixedly connected to the liquid cooling plate; the inlet and outlet of the liquid cooling pipe both extend out of the box body and / or the bottom plate.

8. The battery pack of claim 7, wherein, Including at least one of the following characteristics: Characteristic 4: the side plate and the internal partition plate of the box body are integrally formed; Characteristic 5: the liquid cooling pipe is coiled in an S shape in the horizontal direction of the liquid cooling plate; Characteristic 6: the liquid cooling plate is embedded in the bottom of the box body; Characteristic 7: the material of the bottom plate includes at least one of aluminum and stainless steel.

9. Application of the flame-retardant composite of any one of claims 1-5 in any field of battery and its packaging structure, engine and fuel system, new energy vehicle fast charging device or high-voltage power transmission structure.

10. Use according to claim 9, characterized in that, The application of the flame-retardant composite in the field of battery includes using the flame-retardant composite to prepare a battery shell or a battery cover plate; And / or, the application of the flame-retardant composite in the engine and fuel system includes using the flame-retardant composite to prepare an engine shell or an engine transmission structure.

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