Battery bottom protection plate made of fiber reinforced thermoplastic composite material

Abstract

The utility model provides a battery bottom protection plate made of a fiber-reinforced thermoplastic composite material. The battery bottom protection plate comprises an upper skin, a metal plate and a lower skin, the upper skin is formed by laminating a first hot melt adhesive layer on a first fiber reinforced composite board; the lower skin is formed by laminating a second hot melt adhesive layer on a second fiber reinforced composite plate; the metal plate is located between the upper skin and the lower skin, and the metal plate is melted by the first hot melt adhesive layer and the second hot melt adhesive layer and then hot-pressed to be seamlessly wrapped. The technical problems that in the prior art, the battery bottom protection plate manufacturing process is complex, the airtight grade does not meet the requirement, and the anti-corrosion performance is poor are solved.

Description

Technical Field

[0001] This application belongs to the field of battery bottom protection plate technology, and relates to a battery bottom protection plate made of fiber reinforced thermoplastic composite material. Background Technology

[0002] The fiber-reinforced thermoplastic composites industry is developing rapidly, with more and more high-performance products or components being manufactured using fiber-reinforced thermoplastic composites. Due to their excellent impact resistance, corrosion resistance, and recyclability, they have been widely used in recent years, especially in the battery underbody protection plates of new energy vehicles, to replace traditional pure plastic underbody protection plates, steel underbody protection plates, and fiber-reinforced thermosetting composite underbody protection plates. Other application areas include: cold chain logistics containers, bus roofs, floors, and aviation containers.

[0003] In the field of battery bottom protection plate manufacturing, the existing battery bottom protection plate is made of multiple layers of continuous fiber reinforced thermoplastic composite sheet and a middle layer of galvanized metal sheet, which is fixed by perforation around the perimeter. The middle layer of galvanized metal sheet is surrounded by a frame made of continuous fiber reinforced thermoplastic composite sheet with the same thickness as the metal sheet. An adhesive film is set between the galvanized metal sheet and the upper and lower skin layers to bond the two together.

[0004] The manufacturing process for this structure is complex. A "frame" with the same thickness as the galvanized metal sheet needs to be prefabricated around its perimeter. This frame is composed of multiple layers of continuous fiber-reinforced thermoplastic unidirectional prepreg tape. During continuous production, this frame is typically not a single continuous frame. Instead, it uses two longitudinally unwound edge strips as the two longitudinal sections and one transverse section. The transverse strip is cut during continuous production, with one half serving as the rear transverse edge strip of the previous sheet and the other half as the front transverse edge strip of the next sheet. Therefore, manufacturing this frame requires the following steps: first, continuous fiber-reinforced thermoplastic unidirectional prepreg tape is manufactured using glass fiber and thermoplastic resin; the prepreg tape undergoes two lamination processes; after lamination, it needs to be slit into rolls according to the required edge strip width. The rolls used for the longitudinal edge strips can be directly unwound and used, while the rolls used for the transverse edge strips require a further cutting process. Therefore, a lot of raw materials are required when making the final bottom protection plate: upper and lower skins, upper and lower adhesive films, metal plates, horizontal edge strips, and several vertical edge strips. This results in a complex manufacturing process and equipment structure. Furthermore, the relative positions of the horizontal and vertical edge strips and the middle metal plate are difficult to control during production, leading to insufficient airtightness and inadequate corrosion resistance. Utility Model Content

[0005] This application provides a battery bottom cover plate made of fiber-reinforced thermoplastic composite material, which solves the technical problems of complex manufacturing process, non-compliance with airtightness requirements, and poor corrosion resistance in the prior art.

[0006] The following technical solution is adopted in this application:

[0007] This application provides a battery bottom cover plate made of fiber-reinforced thermoplastic composite material, comprising: an upper skin, a metal plate, and a lower skin;

[0008] The upper skin is formed by laminating a first hot melt adhesive layer onto a first fiber-reinforced composite board;

[0009] The lower skin is formed by laminating a second hot melt adhesive layer onto a second fiber-reinforced composite board;

[0010] The metal plate is located between the upper and lower skins and is seamlessly wrapped by hot pressing after the first and second hot melt adhesive layers are melted.

[0011] Optionally, the first fiber-reinforced composite board contains black masterbatch.

[0012] Optionally, both the first fiber-reinforced composite board and the second fiber-reinforced composite board are made of unidirectional prepreg tape formed by impregnating fibers with thermoplastic resin.

[0013] Optionally, both the first fiber-reinforced composite board and the second fiber-reinforced composite board are multi-layer continuous fiber-reinforced thermoplastic composite boards, long fiber-reinforced thermoplastic composite boards, or short fiber-reinforced thermoplastic composite boards.

[0014] Optionally, the unidirectional prepreg tape of the first fiber reinforced composite board is laid up in one or any combination of XYXY, YXYX, XY, YX, XYX, and YXY.

[0015] Optionally, the upper and lower skins are made of multiple layers of unidirectional prepreg tape of preset thickness, which are then coated with a hot melt adhesive layer on one side.

[0016] Optionally, the layup methods of the unidirectional prepreg tapes of the upper and lower skins may be the same or different.

[0017] Optionally, the thickness of each unidirectional prepreg layer of the upper and lower skin may be the same or different.

[0018] Optionally, the upper and lower skins are the same size, but are laid out in a staggered manner.

[0019] The beneficial effects of this application are:

[0020] 1. The battery bottom cover of this application is formed by bonding a metal plate with a high-flowability hot melt adhesive layer on the upper and lower skins. After heating and melting, a composite pressure is applied to flow and wrap the metal plate with the hot melt adhesive layer on the upper and lower skins, sealing it in one step. Compared with existing bottom covers that pre-cut the edges of the metal plate, connect them one end to the other, and fix them to the upper and lower skins at the four edges to protect the metal plate from exposure, the manufacturing process of this application is simpler and the airtightness of the structure is higher.

[0021] 2. The hot melt adhesive layer of the upper and lower skins of the battery bottom cover of this application uses pure resin with lower porosity, which has better air tightness than fiber-reinforced thermoplastic resin. This is because the fiber has a siphon effect, which introduces air or water into the product. The good air tightness also brings better corrosion resistance and even reduces the requirements for metal plates, eliminating the need for special treatments such as galvanizing.

[0022] 3. In this application, the unidirectional prepreg tape of the upper and lower skins is laid up in an XYXY structure, with multiple layers of different thicknesses bonded together. This saves materials while ensuring the best possible puncture resistance of the outer surface of the battery bottom protector.

[0023] 4. After product testing, the airtightness of the battery bottom cover plate of this application can reach an inlet pressure of 5±0.5kPa, stabilized for 50s, and the stabilized air pressure is 3.5±0.3kPa; the test time is 60s, and the maximum leakage is ≤0.03kPa, which meets the IP67 requirements; in terms of corrosion resistance, it can meet the following: GB / T 10125-2012, after 720 hours of 50g / L neutral salt spray test, no red rust, bubbles or other phenomena appear on the surface, the corrosion of the scratch line does not exceed 2mm, referring to GB / T 6461, the corrosion evaluation is ≥7 level, the appearance grade is ≥D level, which meets the airtightness requirements and corrosion resistance level. Attached Figure Description

[0024] Figure 1 This application provides a schematic diagram showing the positional relationship between the upper and lower skins and the metal plate before hot pressing.

[0025] Figure 2 This application provides a schematic diagram of a misaligned upper and lower skin structure before hot pressing.

[0026] Figure 3 This is a schematic diagram of the structure of a battery bottom protection plate after hot pressing, as provided in this application.

[0027] Wherein: 1. Upper skin; 2. Metal plate; 3. Lower skin; 101. First fiber reinforced composite board; 102. First hot melt adhesive layer; 201. Second fiber reinforced composite board; 202. Second hot melt adhesive layer. Detailed Implementation

[0028] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0029] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0030] The present application will now be described in further detail with reference to the accompanying drawings:

[0031] like Figure 1 As shown, this application provides a battery bottom cover made of fiber-reinforced thermoplastic composite material, which is mainly composed of an upper skin 1, a metal plate 2 and a lower skin 3 bonded together in a multi-layer structure. The upper skin 1 is formed by laminating a first hot melt adhesive layer 102 onto a first fiber-reinforced composite plate 101; the lower skin 3 is formed by laminating a second hot melt adhesive layer 202 onto a second fiber-reinforced composite plate 201; the metal plate 2 is located between the upper skin 1 and the lower skin 3, and is formed by hot-pressing the first hot melt adhesive layer 102 and the second hot melt adhesive layer 202 together to form a seamless cover.

[0032] It should be noted that the metal plate 2 can be a plate with a certain degree of hardness for puncture resistance, such as an aluminum plate or a steel plate, etc., without limitation. Both the upper skin 1 and the lower skin 3 are composed of multi-layer fiber-reinforced thermoplastic composite material and a hot melt adhesive layer. The hot melt adhesive layer has good fluidity and, after modification, can achieve good adhesion with the metal plate 2. During the bonding process, through one-time hot melting and under a certain composite pressure, the high-flow-rate body formed by the hot melt adhesive layer flows into the periphery of the metal plate 2, forming a seamless wrapping layer. The hot melt adhesive layer can be a resin layer or other fusible colloid with high airtightness and adhesion. Taking the hot melt adhesive layer as a resin layer and the metal layer 2 as a steel plate as an example, this process directly eliminates the step of preparing longitudinal and transverse edge strips in advance. Moreover, the modified resin film layer has good adhesion to the steel plate, eliminating the need to add another adhesive film layer, greatly simplifying the product processing process, reducing manufacturing costs, and ensuring that the battery bottom cover has a certain degree of puncture resistance. In addition, the outer wrapping layer of the metal plate 2 has high airtightness and strong corrosion resistance, which improves the service life of the battery bottom protection plate.

[0033] Optionally, both the first fiber-reinforced composite board 101 and the second fiber-reinforced composite board 201 are multi-layer continuous fiber-reinforced thermoplastic composite boards, long fiber-reinforced thermoplastic composite boards, or short fiber-reinforced thermoplastic composite boards.

[0034] Optionally, both the first fiber-reinforced composite board 101 and the second fiber-reinforced composite board 201 are made of unidirectional prepreg tape formed by impregnating fibers with thermoplastic resin.

[0035] Optionally, the first fiber-reinforced composite board contains black masterbatch.

[0036] Optionally, the unidirectional prepreg tape of the first fiber reinforced composite board 101 is laid up in one or any combination of XYXY, YXYX, XY, YX, XYX, and YXY.

[0037] Optionally, the upper and lower skins are made of multiple layers of unidirectional prepreg tape of preset thickness, which are then coated with a hot melt adhesive layer on one side.

[0038] In one embodiment, the first fiber-reinforced composite plate 101 and the second fiber-reinforced composite plate 201 corresponding to the upper skin 1 and lower skin 3 of the battery bottom cover plate in this application are both composed of multi-layer fiber-reinforced thermoplastic composite material and a layer of hot melt adhesive. Preferably, the fiber-reinforced thermoplastic composite material is a sheet made of multi-layer continuous fiber-reinforced thermoplastic prepreg tape. Alternatively, fiber woven fabric impregnated with thermoplastic resin sheet, short fiber or long fiber reinforced thermoplastic composite sheet, fiber felt impregnated with resin sheet, or woven sheet made of continuous fiber-reinforced thermoplastic prepreg tape may be selected.

[0039] The fiber-reinforced thermoplastic composite material of the upper skin 1 and the lower skin 3 preferably uses glass fiber and carbon fiber, but aramid fiber, basalt fiber, ultra-high molecular weight polyethylene fiber, etc. can also be used. The hot melt adhesive layer of the upper skin 1 and the lower skin 3 is preferably polypropylene (PP), but thermoplastic resins such as PE, PA, PET, PPS, ABS, POK, and PEEK can also be used.

[0040] Optionally, the layup methods of the unidirectional prepreg tapes of the upper skin 1 and the lower skin 3 may be the same or different.

[0041] Optionally, the thickness of each unidirectional prepreg layer of the upper skin 1 and the lower skin 3 may be the same or different.

[0042] Optionally, the upper skin 1 and the lower skin 3 are the same size, but are laid flat with their positions staggered.

[0043] Specifically, in the battery bottom cover manufacturing process, an upper skin 1 and a lower skin 3 are first manufactured. The upper skin 1 is formed by laminating a first hot melt adhesive layer 102 onto a first fiber-reinforced composite plate 101. Similarly, the lower skin 3 is formed by laminating a second hot melt adhesive layer 202 onto the second fiber-reinforced composite plate 201. The first fiber-reinforced composite plate 101 of the upper skin 1 is composed of four layers of unidirectional prepreg tape with a preset thickness of 0.25mm, arranged in an XYXY layup structure, totaling 1.0mm in thickness. Black masterbatch is added to the first fiber-reinforced composite plate. The first hot melt adhesive layer 102 is modified polypropylene resin with a melt flow index of 100g / 10min. The lower skin 3 uses essentially the same material as the upper skin 1, but the black masterbatch is removed, leaving it in its natural color. Additionally, the single-layer unidirectional tape is 0.2mm thick, also composed of four layers, totaling 0.8mm in thickness; the metal plate is made of high-strength steel, 0.8mm thick. It should be noted that the layup of each layer of unidirectional prepreg tape in the upper skin 1 and lower skin 3 in this application may be the same or different. That is, if the layup of the unidirectional prepreg tape of the upper skin 1 is XYXY, the layup of the unidirectional prepreg tape of the lower skin 3 may be XYXY, or it may be a combination of XY and XYX or YXY (X represents longitudinal laying and Y represents transverse laying). The layup method is determined based on the optimal performance under different requirements.

[0044] It should be noted that after the upper skin 1 and lower skin 3 are finished with the battery bottom protection plate, their dimensions are identical. However, during the manufacturing process, when the metal plate 2 is sandwiched between the upper skin 1 and lower skin 3, they are misaligned vertically to ensure that the hot melt adhesive layers of the upper skin 1 and lower skin 3 can fully melt and contact each other during the hot-melt process. Figure 2 As shown and Figure 3 As shown, Figure 2 This is a schematic diagram showing the positional relationship between the upper and lower skins and the metal plate before hot pressing. Figure 3This is a schematic diagram of the battery bottom protector after hot pressing. By applying a given heating temperature and combined pressure to the upper skin 1 and lower skin 3, the first hot melt adhesive layer 102 of the upper skin 1 and the second hot melt adhesive layer 202 of the lower skin 2 melt and flow to the periphery of the metal plate 2 until the three layers of the upper skin 1, metal plate 2, and lower skin 3 are seamless, sealed, and flush, without any protrusions or depressions. Finally, the front and rear battery bottom protectors are cut and separated. This method is more suitable for mass production and has a simpler process.

[0045] It should be noted that, in addition to the above, existing technologies for manufacturing battery bottom protectors involve creating multiple holes in the metal plate 2 for fixing or other purposes. If the four edges of the metal plate 2 are made using existing technology and then connected end to end, the bottom protector is encapsulated by combining the upper and lower skins. In this case, the holes on the metal plate 2 also need to be sealed separately, which is cumbersome and carries the risk of poor sealing performance. However, the technical solution provided in this application uses hot melt adhesive layers on the upper and lower skins to wrap the metal plate 2, sealing it in one step, reducing many manufacturing steps and providing better sealing.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and not to limit them. Although this application has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of this application. Any modifications or equivalent substitutions that do not depart from the spirit and scope of this application should be covered within the protection scope of the claims of this application.

Claims

1. A battery undertray of fiber reinforced thermoplastic composite material, characterized in that, The application relates to a metal plate composite board, which comprises an upper skin (1), a metal plate (2) and a lower skin (3). The upper skin (1) is composed of a first thermofusible adhesive layer (102) and a first fiber-reinforced composite plate (101). The lower skin (3) is composed of a second thermofusible adhesive layer (202) and a second fiber-reinforced composite plate (201). The metal plate (2) is located between the upper skin (1) and the lower skin (3) and is fused and hot-pressed by the first thermofusible adhesive layer (102) and the second thermofusible adhesive layer (202) to be seamlessly wrapped. The first fiber-reinforced composite plate (101) and the second fiber-reinforced composite plate (201) are both composed of unidirectional prepreg tapes formed by thermoplastic resin impregnated fibers.

2. A fiber reinforced thermoplastic composite battery floor pan as in claim 1, wherein, The first fiber-reinforced composite plate (101) and the second fiber-reinforced composite plate (201) are one of a multi-layer continuous fiber-reinforced thermoplastic composite plate, a long fiber-reinforced thermoplastic composite plate or a short fiber-reinforced thermoplastic composite plate.

3. A fiber reinforced thermoplastic composite battery floor pan as in claim 1, wherein, The laying mode of the unidirectional prepreg tapes of the first fiber-reinforced composite plate (101) is any one of XYXY, YXYX, XY, YX, XYX or YXY or any combination mode.

4. The fiber reinforced thermoplastic composite battery foot shield of any one of claims 1 or 2, wherein, The X represents laying along the longitudinal direction of the first fiber-reinforced composite plate (101), and the Y represents laying along the transverse direction of the first fiber-reinforced composite plate (101). The upper skin (1) and the lower skin (3) are composed of multiple layers of unidirectional prepreg tapes with a preset thickness and then are single-sidedly coated with a thermofusible adhesive layer.

5. A fiber reinforced thermoplastic composite battery floor pan as defined in claim 1, wherein, The laying mode of the unidirectional prepreg tapes of the upper skin (1) and the lower skin (3) is consistent or inconsistent.

6. A fiber reinforced thermoplastic composite battery floor pan as defined in claim 1, wherein, The thickness of each layer of the unidirectional prepreg tapes of the upper skin (1) and the lower skin (3) is consistent or inconsistent.

7. A fiber reinforced thermoplastic composite battery floor pan as defined in claim 1, wherein, The size of the upper skin (1) and the lower skin (3) is the same, and the upper skin and the lower skin are laid in a staggered manner.

8. The fiber reinforced thermoplastic composite battery foot shield of any one of claims 1 or 7, wherein, ​

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