Power battery sealing cover, battery pack and electric vehicle

Abstract

The utility model relates to the technical field of batteries, and discloses a power battery sealing cover, a battery pack and an electric vehicle, the power battery sealing cover comprises a cover body, the cover body comprises a composite board, the composite board comprises a first composite layer, a core layer and a second composite layer which are stacked in sequence, the first composite layer and the second composite layer respectively comprise at least one layer of continuous fiber reinforced thermoplastic resin prepreg sheet, the core layer comprises a plurality of glass fibers, and the plurality of glass fibers are woven in a criss-cross manner to form a net-shaped structure. The power battery sealing cover disclosed by the utility model has the advantages of high strength, light weight, high rigidity, better flame retardant property and the like, and conforms to the low-carbon and environment-friendly concept.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a power battery sealing cover, a battery pack and an electric vehicle. Background Art

[0002] Against the backdrop of increasingly severe global natural and oil resource constraints, new energy vehicles, led by electric vehicles, have emerged as a rising star. Compared to traditional fuel-powered vehicles, they use electricity and produce no harmful gases like carbon monoxide and carbon dioxide, thus reducing environmental pollution. The battery pack is the core of new energy vehicles, impacting their performance and safety. While increasing the battery pack's energy density increases driving range to a certain extent, it also increases safety and reliability risks. The sealing cap, located above the battery pack, isolates the battery, the vehicle cabin, and the external driving environment. It must protect the battery, improve driving range, and enhance safety. Therefore, material requirements are high for mechanical strength, lightweight, and fire resistance. Initially, the main materials used for sealing caps in new energy vehicles were metal (steel, aluminum alloy) and polypropylene (PP). However, the high density of metal significantly increases the overall weight of the battery pack, impacting battery life. While PP blister-formed sealing caps have a low density, contributing to weight reduction and good formability, they lack flame retardancy and are not fire-resistant. In the event of a collision or spontaneous battery combustion, they are unable to prevent the entry of fireworks, liquids, and gases into the vehicle cabin, posing a safety hazard.

[0003] Patent CN107452905A discloses a battery pack sealing cover, including a fiber layer containing a mesh structure. By filling the holes of the mesh structure with an adhesive, a sealable whole is formed. Under normal circumstances, the battery is waterproof, lightweight, low-cost, and insulated. In extreme cases, when the battery pack is short-circuited, overcharged, etc., causing a fire inside the battery pack, the adhesive on the sealing cover can melt or volatilize at high temperatures. The sealing cover has a mesh structure and is breathable, which can effectively discharge gas and avoid the rapid accumulation of gas generated by the battery under extreme conditions, causing the internal pressure of the battery pack to increase rapidly, resulting in explosion and other dangers. However, this method requires the attachment of adhesives and other functional additives to the fiber layer through methods such as impregnation and coating. It has many processes and is time-consuming. In addition, the adhesive is mainly thermosetting resin, has a strong odor, and is non-recyclable, which does not conform to the current low-carbon and environmental protection concept. Utility Model Content

[0004] The primary purpose of the utility model is to provide a power battery sealing cover that has good fire resistance and mechanical properties and is low-carbon and environmentally friendly.

[0005] Another object of the present utility model is to provide a battery pack using the power battery sealing cover;

[0006] Another object of the present utility model is to provide an electric vehicle using the above battery pack.

[0007] To solve the above technical problems, the present utility model provides the following technical solutions:

[0008] A power battery sealing cover includes a cover body, the cover body includes a composite plate, the composite plate includes a first composite layer, a core layer and a second composite layer which are laminated in sequence, the first composite layer and the second composite layer respectively include at least one layer of continuous fiber reinforced thermoplastic resin prepreg, the core layer includes a plurality of glass fibers, and the plurality of glass fibers are woven in a crisscross manner to form a net structure.

[0009] Preferably, the lay-up between the first composite layer and the second composite layer is symmetric. When both the first composite layer and the second composite layer include at least two layers of the continuous fiber reinforced thermoplastic resin prepreg, the lay-up angle difference between two adjacent layers of the continuous fiber reinforced thermoplastic resin prepreg in the first composite layer and the second composite layer is α, where 10° < α < 100°.

[0010] Preferably, at least one layer of the continuous fiber reinforced thermoplastic resin prepreg in the first composite layer and the second composite layer for being close to the battery contains a flame retardant.

[0011] Preferably, the thickness of the composite plate is 1.2 - 2.4 mm.

[0012] Preferably, the thickness of the core layer is 0.1 - 0.5 mm.

[0013] Preferably, the fiber in the continuous fiber reinforced thermoplastic resin prepreg is one or more of carbon fiber and glass fiber.

[0014] Preferably, the single filament bundle of the carbon fiber in the continuous fiber reinforced thermoplastic resin prepreg is 1000 - 50000, the linear density of the glass fiber bundle in the continuous fiber reinforced thermoplastic resin prepreg is 1200 tex, 2400 tex or 4800 tex; the filament density of the glass fiber in the core layer is 1200 tex, 2400 tex or 4800 tex, and the grammage of the glass fiber in the core layer is 200 - 1200 gsm.

[0015] Preferably, the thickness of the continuous fiber reinforced thermoplastic resin prepreg is 0.1 - 0.5 mm.

[0016] The present utility model also relates to a battery pack, including a box body, a battery pack and the above power battery sealing cover, the box body has an opening, the battery pack is arranged in the box body, and the power battery sealing cover seals the opening of the box body.

[0017] The present utility model also relates to an electric vehicle, including the battery pack described above.

[0018] Compared with the prior art, the beneficial effects of the power battery sealing cover in the embodiments of the present utility model are as follows:

[0019] In the present utility model, the cover body of the power battery sealing cover of the present application is made of a composite plate, and the composite plate includes a first composite layer and a second composite layer, and a core layer disposed between the first composite layer and the second composite layer. Each of the first composite layer and the second composite layer includes at least one layer of continuous fiber reinforced thermoplastic resin prepreg, and the content of continuous reinforcing fibers is 40%-60%. The composite layer prepared by using the continuous fiber reinforced thermoplastic resin prepreg not only has the advantages of high strength, high stiffness and flame retardancy of continuous fibers, but also has the advantages of low density and good formability of thermoplastic resin, so that the cover body of the battery sealing cover has the advantages of high strength, high stiffness and good flame retardancy while being lightweight. Further, a core layer formed by crisscrossing and weaving a plurality of glass fibers into a network structure is also disposed between the first composite layer and the second composite layer, further improving the flame retardancy and fire resistance, so as to effectively prevent the flame from burning through the power battery sealing cover. Description of the Drawings

[0020] Figure 1 is a schematic diagram of the overall structure of an embodiment of the present utility model;

[0021] Figure 2 is a schematic diagram of the first composite layer of an embodiment of the present utility model;

[0022] Figure 3 is a schematic diagram of the second composite layer of an embodiment of the present utility model.

[0023] In the figure, 1, the first composite layer; 2, the core layer; 3, the second composite layer; 4, the continuous fiber reinforced thermoplastic resin prepreg. Detailed Embodiments

[0024] The following will describe in further detail the specific embodiments of the present utility model in conjunction with the drawings and embodiments. The following embodiments are used to illustrate the present utility model, but are not used to limit the scope of the present utility model.

[0025] In the description of the present utility model, it should be understood that the term "comprising" used in the specification of the present utility model means the presence of the described features, integers, steps, operations, components and / or assemblies, but does not exclude the presence or addition of one or more other features, integers, steps, operations, components, assemblies and / or their groups. It should be understood that when we say that a component is "connected" to another component, it can be directly connected to the other component, or there may also be intermediate components. The term "and / or" used herein includes any and all combinations of one or more of the associated listed items.

[0026] As Figures 1 to 3 shown, the present utility model relates to a power battery sealing cover, which comprises a cover body. The cover body comprises a composite plate. The composite plate comprises a first composite layer 1, a core layer 2 and a second composite layer 3 which are laminated and hot-pressed together in sequence. The first composite layer 1 and the second composite layer 3 respectively comprise at least one layer of continuous fiber reinforced thermoplastic resin prepreg 4. The core layer 2 comprises a plurality of glass fibers. The plurality of glass fibers are woven in a crisscross pattern to form a net structure. Specifically, the core layer 2 is a glass fiber grid cloth.

[0027] In the present utility model, the cover body of the power battery sealing cover of the present application is made of a composite plate. The composite plate comprises a first composite layer 1 and a second composite layer 3, and a core layer 2 disposed between the first composite layer 1 and the second composite layer 3. The first composite layer 1 and the second composite layer 3 respectively comprise at least one layer of continuous fiber reinforced thermoplastic resin prepreg 4, so that it has recyclability and conforms to low-carbon travel. The continuous fiber reinforced thermoplastic resin prepreg 4 is made by a melt impregnation method with continuous reinforcing fibers and thermoplastic resin, and the content of the continuous reinforcing fibers is 40%-60%, so that the continuous fiber reinforced thermoplastic resin prepreg 4 has better flame retardant performance. At the same time, the continuous fiber reinforced thermoplastic resin prepreg 4 also has the advantages of high strength, light weight and high stiffness. Furthermore, the power battery sealing cover has the advantages of high strength, light weight, high stiffness and better flame retardant performance. Then, a core layer 2 formed by weaving a plurality of glass fibers in a crisscross pattern is also disposed between the first composite layer 1 and the second composite layer 3, so as to effectively prevent the flame from burning through the power battery sealing cover and further improve the fire resistance of the power battery sealing cover.

[0028] It should be noted that the thermoplastic resin is PP, PA, PC, etc.

[0029] In this embodiment, a symmetric layup is provided between the first composite layer 1 and the second composite layer 3. When both the first composite layer 1 and the second composite layer 3 include at least two layers of the continuous fiber reinforced thermoplastic resin prepreg sheets 4, the layup angle difference between two adjacent layers of the continuous fiber reinforced thermoplastic resin prepreg sheets 4 in the first composite layer 1 and the second composite layer 3 is α, where 10° < α < 100°.

[0030] By making the layup angles of two adjacent layers of the continuous fiber reinforced thermoplastic resin prepreg sheets 4 greater than 10° and less than 100°, it is beneficial to form a dense structure for both the first composite layer 1 and the second composite layer 3, so that when exposed to fire, the layers can support each other and will not collapse.

[0031] In this embodiment, at least one layer of the continuous fiber reinforced thermoplastic resin prepreg sheet 4 in the first composite layer 1 and the second composite layer 3 that is close to the battery is added with a flame retardant, so that the side of the power battery seal cover close to the battery directly plays a flame retardant role, having a better flame retardant effect.

[0032] In this embodiment, the thickness of the composite board is 1.2 - 2.4 mm, so that the power battery seal cover has sufficient strength and sufficient flame retardant effect.

[0033] In this embodiment, the thickness of the core layer 2 is 0.1 - 0.5 mm to ensure certain fire resistance and certain structural strength.

[0034] In this embodiment, the fibers in the continuous fiber reinforced thermoplastic resin prepreg sheet 4 are one or more of carbon fibers and glass fibers.

[0035] The cost of carbon fibers is relatively high, while the cost of glass fibers is relatively low. Therefore, the continuous fiber reinforced thermoplastic resin prepreg sheet 4 is made of a mixture of carbon fibers and glass fibers, which can reduce the manufacturing cost. At the same time, the strength and stiffness of carbon fibers are higher than those of glass fibers, while the toughness of glass fibers is better than that of carbon fibers. Thus, the overall strength and stiffness of the continuous fiber reinforced thermoplastic resin prepreg sheet 4 can also be improved by mixing the two, thereby improving the overall strength and stiffness of the power battery seal cover.

[0036] Specifically, the single filament bundle of carbon fibers in the continuous fiber reinforced thermoplastic resin prepreg sheet 4 is 1,000 - 50,000, and the linear density of the fiber bundle of glass fibers is 1200 tex, 2400 tex or 4800 tex, which is conducive to the infiltration of the thermoplastic matrix to form a continuous fiber reinforced thermoplastic resin prepreg sheet 4 with good performance. Moreover, the thickness of the continuous fiber reinforced thermoplastic resin prepreg sheet 4 is 0.1 - 0.5 mm to more effectively achieve the sealing and protection effect of the power battery sealing cover under normal circumstances.

[0037] In this embodiment, the filament density of the glass fibers in the core layer 2 is 1200 tex, 2400 tex or 4800 tex, and the grammage of the glass fibers is 200 - 1200 gsm to ensure that the core layer 2 has certain fire resistance while achieving lightweight.

[0038] In this embodiment, the resin matrix in the continuous fiber reinforced thermoplastic resin prepreg sheet 4 is a combination of one or several of polypropylene resin, flame retardant, compatibilizer, antioxidant and filler in any ratio.

[0039] The design of the continuous fiber reinforced thermoplastic resin prepreg sheet 4 enables the core layer 2 to be effectively bonded to the first composite layer 1 and the second composite layer 3 when the power battery sealing cover is not on fire; after being burned off, the core layer 2 can be automatically separated from the first composite layer 1 and the second composite layer 3, allowing air to exist among the three, reducing the thermal conductivity coefficient of the power battery sealing cover and improving its fire resistance and combustion performance.

[0040] It should be noted that the flame retardant is at least one of halogenated flame retardants and non - halogenated flame retardants.

[0041] The compatibilizer includes maleic anhydride grafted polypropylene, with a melt index of 30 - 200 g / 10 min at 190 °C and 2.16 kg, an odor grade of 2 - 3, and a melting point of 160 °C - 170 °C. The ratio of the compatibilizer to the thermoplastic resin is 1:8 - 20.

[0042] The antioxidant is a phosphorus - based antioxidant, and the ratio of the antioxidant to the thermoplastic resin is 1:40 - 90.

[0043] The filler includes one or a combination of fillers such as silicone masterbatch, calcium carbonate, mica powder, color powder, etc. Among them, the particle sizes of calcium carbonate and mica powder should be ≤ 70 microns.

[0044] In this embodiment, the difference between the core layer 2 formed by interweaving multiple glass fibers in a crisscross pattern to form a network structure and the first composite layer 1 and the second composite layer 3 is that the woven fibers of the core layer 2 are cross - crossed within the layer of fibers. When exposed to fire, it can form a better dense structure, ensuring that the product will not burn through during the fire and still maintaining its original structure after the fire. While the first composite layer 1 and the second composite layer 3 are both cross - crossed between layers of fibers, and the thermoplastic resin has good wettability with the fibers, so that the mechanical properties of the first composite layer 1 and the second composite layer 3 are relatively excellent. Therefore, in this application, the core layer 2 is combined with the first composite layer 1 and the second composite layer 3, so that the power battery sealing cover has good mechanical properties and fire - resistance performance.

[0045] The following takes the power battery sealing cover as an example and combines some specific embodiments to illustrate the fire - resistance performance and mechanical properties of the power battery sealing cover of this application.

[0046] Laying scheme: Scheme one, the composite board only includes the continuous fiber reinforced thermoplastic resin prepreg 4, and the laying angle of this composite board is 100° / 10° / 0° / 10° / 100°, and the thickness of a single - layer continuous fiber reinforced thermoplastic resin prepreg 4 is 0.3 mm; Schemes two and three, the composite board includes a first composite layer, a core layer of woven fibers, and a second composite layer stacked in sequence, and the laying angle is 100° / 10° / woven fiber / 10° / 100°, the thickness of a single - layer continuous fiber reinforced thermoplastic resin prepreg 4 is 0.3 mm, and the grammage of the woven fiber is 600 gsm.

[0047] It should be noted that the continuous fibers of the continuous fiber reinforced thermoplastic resin prepreg 4 are one or more of carbon fibers or glass fibers. The linear density of the fiber bundle of the glass fiber in the continuous fiber reinforced thermoplastic resin prepreg 4 is 1200 tex, 2400 tex or 4800 tex. The single - filament bundle of the carbon fiber in the continuous fiber reinforced thermoplastic resin prepreg 4 is 1000 - 50000 filaments. The resin is polypropylene resin. Among them, a flame retardant is also added to the V0 - flame - retardant continuous fiber reinforced thermoplastic resin prepreg, and no flame retardant is added to the non - flame - retardant continuous fiber reinforced thermoplastic resin prepreg. And the thickness and other factors of the composite boards in Schemes one to three are kept the same.

[0048] And specifically form the following multiple combined schemes:

[0049] Scheme one: V0 - flame - retardant / V0 - flame - retardant / V0 - flame - retardant / V0 - flame - retardant / V0 - flame - retardant;

[0050] Scheme two: V0 - flame - retardant / V0 - flame - retardant / woven fiber / V0 - flame - retardant / V0 - flame - retardant;

[0051] Scheme three: V0 - flame - retardant / non - flame - retardant / woven fiber / V0 - flame - retardant / V0 - flame - retardant;

[0052] Description of the material combination plan:

[0053] For Plan 1, Plan 2, and Plan 3, they are to verify the influence of replacing the middle layer of the composite board with a core layer of woven fibers on the performance of the composite board;

[0054] For Plan 2 and Plan 3, they are to verify the influence of the proportion of the flame-retardant continuous fiber-reinforced thermoplastic resin prepreg on the performance of the composite board with a core layer containing woven fibers;

[0055] Test results:

[0056] Fire test (burn for 2 hours under the condition that the flame temperature is 1200 °C)

[0057]

[0058] It is determined whether the sealing cover is burned through by whether it is light-transmitting, indicating that the core layer of woven fibers can effectively prevent the flame from burning through the fabric composite;

[0059] Tensile test (GB / T1040-2006, dumbbell-shaped tensile specimen)

[0060]

[0061]

[0062] The composite board adopted by the power battery sealing cover of the present application is the plan shown in Plan 2 or Plan 3 above. Therefore, from the above test results, it can be known that the present application combines the core layer 2 of woven fibers with the first composite layer 1 and the second composite layer 3, so that the power battery sealing cover can have good mechanical properties and fire resistance.

[0063] It should be noted that the first composite layer 1 and the second composite layer 3 can design the laying structure, number of layers, thickness, etc. of the continuous fiber-reinforced thermoplastic resin prepreg 4 according to the requirements of the product to meet the usage requirements of various products.

[0064] The present utility model also relates to a battery pack, including a box body, a battery pack, and the power battery sealing cover. The box body has an opening, the battery pack is arranged in the box body, and the power battery sealing cover seals the opening of the box body.

[0065] By adopting the power battery sealing cover, when a fire occurs inside the battery pack, the power battery cover can prevent the flame from burning through the power battery sealing cover and prevent the flame from escaping, improving safety.

[0066] The present utility model also relates to an electric vehicle, including the battery pack. By adopting the battery pack, it is possible to prevent the flame from spreading when the battery pack catches fire, so as to ensure the safety of the electric vehicle during use.

[0067] The above are only the preferred embodiments of the present utility model. It should be noted that for those of ordinary skill in the art of the present technology, without departing from the technical principle of the present utility model, several improvements and substitutions can be made, and these improvements and substitutions should also be regarded as the protection scope of the present utility model.

Claims

1. A power battery sealing cover, characterized in that It includes a cover body, and the cover body includes a composite board. The composite board includes a first composite layer, a core layer, and a second composite layer which are laminated in sequence. The first composite layer and the second composite layer each include at least one layer of continuous fiber reinforced thermoplastic resin prepreg. The core layer includes multiple glass fibers, and the multiple glass fibers are woven in a criss-cross pattern to form a network structure. The thickness of the composite board is 1.2 - 2.4 mm, and the thickness of the core layer is 0.1 - 0.5 mm.

2. The power battery sealing cover according to claim 1, wherein, There is a symmetric ply between the first composite layer and the second composite layer. When both the first composite layer and the second composite layer include at least two layers of the continuous fiber reinforced thermoplastic resin prepreg, the ply angle difference between two adjacent layers of the continuous fiber reinforced thermoplastic resin prepreg in the first composite layer and the second composite layer is α, where 10° < α < 100°.

3. The power battery sealing cover according to claim 1, wherein, The fibers in the continuous fiber reinforced thermoplastic resin prepreg are carbon fibers or glass fibers.

4. The power battery sealing cover according to claim 3, characterized in that, The single filament bundle of the carbon fibers in the continuous fiber reinforced thermoplastic resin prepreg is 1000 - 50000, and the linear density of the glass fiber bundle of the continuous fiber reinforced thermoplastic resin prepreg is 1200 tex, 2400 tex, or 4800 tex; the linear density of the glass fiber bundle of the core layer is 1200 tex, 2400 tex, or 4800 tex, and the grammage of the glass fiber of the core layer is 200 - 1200 gsm.

5. The power battery sealing cover according to claim 1, characterized in that, The thickness of the continuous fiber reinforced thermoplastic resin prepreg is 0.1 - 0.5 mm.

6. A battery pack, characterized in that, It includes a box body, a battery pack, and the power battery sealing cover according to any one of claims 1 - 5. The box body has an opening, the battery pack is arranged in the box body, and the power battery sealing cover seals the opening of the box body.

7. An electric vehicle, characterized in that, It includes the battery pack according to claim 6.

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