Battery bottom protection plate made of fiber-reinforced thermoplastic composite material and preparation method of battery bottom protection plate

Abstract

The invention provides a battery bottom protection plate made of a fiber-reinforced thermoplastic composite material and a preparation method thereof, and 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] The present application belongs to the technical field of battery bottom guard plates, and relates to a battery bottom guard plate of a fiber-reinforced thermoplastic composite material and a preparation method thereof. Background Art

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

[0003] In the field of battery bottom guard plate manufacturing, the bottom guard plate of the battery in the prior art is made of multiple layers of continuous fiber reinforced thermoplastic composite sheets and a middle layer of galvanized metal plate fixed by punching holes on all sides, wherein the middle layer of galvanized metal plate is surrounded by a frame made of continuous fiber reinforced thermoplastic composite sheet with the same thickness as the metal plate, and an adhesive film is provided between the galvanized metal plate and the upper and lower surface layers to bond the two.

[0004] The processing process of this structure is complicated. Since a "frame" needs to be made in advance around the galvanized metal plate, the thickness of this frame is the same as that of the metal plate, and it is made of multiple layers of continuous fiber-reinforced thermoplastic unidirectional prepreg tapes laid and compounded. During continuous production, this frame usually does not use a continuous frame, but uses two longitudinal unrolled edge strips as the two longitudinal edges of the frame and one transverse edge strip. The transverse edge strip is cut crosswise during continuous production, half of which is used as the rear transverse edge strip of the previous plate, and the other half is used as the front transverse edge strip of the next plate. Therefore, the manufacture of this frame requires the following process: first, continuous fiber-reinforced thermoplastic unidirectional prepreg tapes are made with glass fiber and thermoplastic resin, and the prepreg tapes are compounded twice. After the compounding is completed, it needs to be cut into rolls according to the width of the edge strips required by the product. Finally, the cut rolls for the longitudinal edge strips can be directly unrolled for use, while the transverse edge strips need to go through a process of cutting into pieces. For this reason, a lot of raw materials are needed when making the final bottom guard plate: upper and lower surfaces, upper and lower adhesive films, metal plates, horizontal edge strips, and several vertical edge strips, which leads to complicated production processes and equipment structures. In addition, the relative positions of the horizontal and vertical edge strips and the middle metal plates are difficult to control during production, resulting in insufficient airtightness and corrosion resistance. Summary of the invention

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

[0006] This application adopts the following technical solutions: The present application provides a fiber-reinforced thermoplastic composite battery bottom guard plate, comprising: an upper surface skin, a metal plate and a lower surface skin; The upper surface is formed by laminating the first hot melt adhesive layer on the first fiber reinforced composite board; The lower skin is formed by laminating the second hot melt adhesive layer on the second fiber reinforced composite board; The metal plate is located between the upper surface and the lower surface, and is seamlessly wrapped by hot pressing after the first hot melt adhesive layer and the second hot melt adhesive layer are melted.

[0007] Optionally, the first fiber-reinforced composite panel contains black masterbatch.

[0008] Optionally, the first fiber-reinforced composite plate and the second fiber-reinforced composite plate are both composited from unidirectional prepreg tapes formed by impregnating fibers with thermoplastic resin.

[0009] Optionally, the first fiber reinforced composite plate and the second fiber reinforced composite plate are both a multi-layer continuous fiber reinforced thermoplastic composite plate or a long fiber reinforced thermoplastic composite plate or a short fiber reinforced thermoplastic composite plate.

[0010] Optionally, the plying method of the unidirectional prepreg tape of the first fiber reinforced composite panel is one of XYXY, YXYX, XY, YX, XYX, YXY or any combination thereof.

[0011] Optionally, the upper skin and the lower skin are formed by compounding multiple layers of unidirectional prepreg tapes of preset thickness and then coating them with a hot melt adhesive layer on one side.

[0012] Optionally, the layup methods of the unidirectional prepreg tapes of the upper skin and the lower skin are consistent or inconsistent.

[0013] Optionally, the thickness of each layer of the unidirectional prepreg tape of the upper skin and the lower skin is consistent or inconsistent.

[0014] Optionally, the upper epidermis and the lower epidermis have the same size and are laid flat in an offset manner.

[0015] The present application also provides a method for preparing a battery bottom guard plate of a fiber-reinforced thermoplastic composite material, comprising: The unidirectional prepreg tape formed by impregnating the fibers with resin is composited into a first fiber-reinforced composite panel and a second fiber-reinforced composite panel.

[0016] A first hot melt adhesive layer of a preset thickness is laminated on the first fiber reinforced composite board to form an upper skin; in the same way, a second hot melt adhesive layer is laminated on the second fiber reinforced composite board to form a lower skin; wherein, the upper skin and the lower skin are respectively laminated on the surface of the first fiber reinforced composite board and the second fiber reinforced composite board by a laminating machine, and the process parameters of the laminating machine are: heating temperature of 100~300℃, laminating die gap of 0.5~5mm, line speed of 0.5~30m / min, and roller pressure of 0.1~3MPa.

[0017] After the hot melt adhesive layers of the upper and lower surfaces are bonded to the metal plate and heated and melted, the hot melt adhesive layers of the upper and lower surfaces are flow-sealed and wrapped around the metal plate by a given composite pressure until there is no gap and the three-layer structure of the upper surface, the metal plate and the lower surface is flush without protrusions or depressions.

[0018] Optionally, the resin melt index of the first hot melt adhesive layer or the second hot melt adhesive layer is 50-1000 g / 10 min.

[0019] Optionally, in parts by mass, the material composition of the first hot melt adhesive layer or the second hot melt adhesive layer is: PP resin: 100 parts, compatibilizer: 0.5-5 parts, coupling agent: 0.5-2 parts, antioxidant: 0.3-3 parts.

[0020] The compatibilizer is one or more of maleic anhydride grafted PP, maleic anhydride grafted PE, maleic anhydride grafted PEO, random ethylene-methyl acrylate-maleic anhydride terpolymer, and the like.

[0021] The coupling agent is one or more of an aminosilane coupling agent, an epoxysilane coupling agent, an acyloxysilane coupling agent, and a vinylsilane coupling agent.

[0022] The antioxidant is one or more of hindered phenol antioxidants, phosphite antioxidants, sulfur antioxidants, and salicylic acid esters.

[0023] The beneficial effects of this application are: 1. The battery bottom guard plate of the present application is formed by attaching the high-flow hot-melt adhesive layer of the upper and lower skins to the metal plate and heating and melting it. The hot-melt adhesive layer of the upper and lower skins is flowed and wrapped around the metal plate under a given composite pressure, and sealed in one step. Compared with the existing bottom guard plate, which pre-cuts the borders around the metal plate, then connects them in sequence, and fixes them together with the upper and lower skins at the four borders to protect the metal plate from being exposed, the manufacturing process of the present application is simpler and the structure is more airtight.

[0024] 2. The hot melt adhesive layer of the upper and lower surfaces of the battery bottom guard plate of the present application adopts pure resin with lower porosity, which has better air tightness than fiber-reinforced thermoplastic resin. Because the fiber has a siphon effect, it introduces air or water into the product. Good air tightness also brings better corrosion resistance, and even the requirements for metal plates will be reduced, without the need for special treatment such as galvanizing.

[0025] 3. In this application, the plying method of the unidirectional prepreg tapes of the upper and lower surfaces is an XYXY structure, and the upper and lower layers are bonded in different thicknesses. While saving materials, it ensures the optimal anti-puncture performance of the outer surface of the battery bottom guard plate as much as possible.

[0026] 4. After product testing, the air tightness of the battery bottom guard plate of this application can reach an intake pressure of 5±0.5kPa, voltage stabilization for 50s, and an air pressure of 3.5±0.3kPa after voltage stabilization; the test time is 60s, and the maximum leakage is ≤0.03kPa, meeting the IP67 requirements; the corrosion resistance can meet: GB / T 10125-2012, meeting the 50g / L neutral salt spray test for 720 hours, no red rust, bubbles, etc. appear on the surface, and the scratch line corrosion does not exceed 2mm. Referring to GB / T 6461, the corrosion evaluation is ≥ level 7, and the appearance level is ≥ level D, meeting the air tightness requirements and corrosion resistance level. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the positional relationship between the upper and lower skins and the metal plates before hot pressing provided in this application.

[0028] Figure 2 A schematic diagram of the upper and lower skin misalignment structure before hot pressing provided in this application.

[0029] Figure 3 A schematic structural diagram of a hot-pressed battery bottom guard plate provided in this application.

[0030] Figure 4 A schematic diagram of the steps of a method for preparing a battery bottom guard plate made of a fiber-reinforced thermoplastic composite material provided in the present application.

[0031] Wherein: 1. upper surface; 2. metal plate; 3. lower surface; 101. first fiber reinforced composite plate; 102. first hot melt adhesive layer; 201. second fiber reinforced composite plate; 202. second hot melt adhesive layer. DETAILED DESCRIPTION

[0032] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0033] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0034] The present application is further described in detail below with reference to the accompanying drawings: like Figure 1 As shown, the present application provides a battery bottom guard plate of a fiber reinforced thermoplastic composite material, which is mainly formed by bonding an upper skin 1, a metal plate 2 and a lower skin 3 together in a multilayer structure, wherein the upper skin 1 is formed by laminating a first hot-melt adhesive layer 102 on a first fiber reinforced composite plate 101; the lower skin 3 is formed by laminating a second hot-melt adhesive layer 202 on 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 hot-pressed to a seamless package after the first hot-melt adhesive layer 102 and the second hot-melt adhesive layer 202 are melted.

[0035] It should be noted that the metal plate 2 can be a plate with a certain hardness for puncture prevention, which can be an aluminum plate or a steel plate, etc., and is not limited here. The upper skin 1 and the lower skin 3 are both composed of multiple layers of fiber-reinforced thermoplastic composite materials and a layer of hot-melt adhesive layer. The hot-melt adhesive layer has good fluidity and can be modified to achieve good bonding with the metal plate 2. In the bonding process, through a one-time hot melt and a given certain composite pressure, the high-fluidity formed by the hot-melt adhesive layer flows into the surrounding of the metal plate 2 and forms a seamless wrapping layer. Among them, the hot-melt adhesive layer can be a resin layer or other colloids that can be melted and have high air tightness 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 need to prepare the longitudinal and transverse edge strips in advance, and the modified resin film layer and the steel plate have good adhesion, eliminating the process of adding another layer of adhesive film layer, greatly simplifying the product processing process, reducing manufacturing costs, and ensuring that the battery bottom guard plate has a certain degree of puncture resistance. In addition, the outer wrapping layer of the metal plate 2 has high air tightness and strong corrosion resistance, which increases the service life of the battery bottom guard plate.

[0036] Optionally, the first fiber reinforced composite plate 101 and the second fiber reinforced composite plate 201 are both a multi-layer continuous fiber reinforced thermoplastic composite plate or a long fiber reinforced thermoplastic composite plate or a short fiber reinforced thermoplastic composite plate.

[0037] Optionally, the first fiber reinforced composite plate 101 and the second fiber reinforced composite plate 201 are both composited from unidirectional prepreg tapes formed by impregnating fibers with thermoplastic resin.

[0038] Optionally, the first fiber-reinforced composite panel contains black masterbatch.

[0039] Optionally, the plying method of the unidirectional prepreg tape of the first fiber reinforced composite panel 101 is one of XYXY, YXYX, XY, YX, XYX, and YXY, or any combination thereof.

[0040] Optionally, the upper skin and the lower skin are formed by compounding multiple layers of unidirectional prepreg tapes of preset thickness and then coating them with a hot melt adhesive layer on one side.

[0041] In one embodiment, the first fiber reinforced composite plate 101 and the second fiber reinforced composite plate 201 corresponding to the upper surface 1 and the lower surface 3 of the battery bottom guard plate in the present application are both composed of multiple layers of fiber reinforced thermoplastic composite materials and a layer of hot melt adhesive; Preferably, the fiber reinforced thermoplastic composite material is a sheet composited by multiple layers of continuous fiber reinforced thermoplastic prepreg tapes, and may also be a fiber woven cloth impregnated with thermoplastic resin sheet, a short fiber or long fiber reinforced thermoplastic composite sheet, a fiber felt impregnated with resin sheet, or a woven sheet woven from continuous fiber reinforced thermoplastic prepreg tapes, etc.

[0042] The fiber-reinforced thermoplastic composite material of the upper skin 1 and the lower skin 3 is preferably glass fiber and carbon fiber, and aramid fiber, basalt fiber, ultra-high molecular weight polyethylene fiber, etc. can also be selected.

[0043] The hot melt adhesive layer of the upper skin 1 and the lower skin 3 is preferably made of polypropylene (PP), and thermoplastic resins such as PE, PA, PET, PPS, ABS, POK, and PEEK may also be used.

[0044] Optionally, the laying methods of the unidirectional prepreg tapes of the upper skin 1 and the lower skin 3 are consistent or inconsistent.

[0045] Optionally, the thickness of each layer of the unidirectional prepreg tape of the upper skin 1 and the lower skin 3 is consistent or inconsistent.

[0046] Optionally, the upper surface 1 and the lower surface 3 have the same size and are laid flat in an offset manner up and down.

[0047] Specifically, in the process of making the battery bottom guard plate, the upper skin 1 and the lower skin 3 are first made, and the first hot melt adhesive layer 102 is coated on the first fiber reinforced composite plate 101 to form the upper skin 1; in the same way, the second hot melt adhesive layer 202 is coated on the second fiber reinforced composite plate 201 to form the lower skin 3. The first fiber reinforced composite plate 101 of the upper skin 1 is composed of four layers of unidirectional prepreg tapes with a preset thickness of 0.25 mm, which are composited in an XYXY structure in a ply manner, with a total thickness of 1.0 mm, and black masterbatch is added to the first fiber reinforced composite plate. The first hot melt adhesive layer 102 is a modified polypropylene resin with a melt index of 100g / 10min. The material used for the lower surface layer 3 is basically the same as that of the upper skin 1, except that the black masterbatch is removed, and it is the original color. In addition, the thickness of the single-layer unidirectional tape is 0.2 mm, and it is also a four-layer composite with a total thickness of 0.8 mm; metal plate: high-strength steel plate is used, 0.8 mm thick. It should be noted that the laying method of each layer of unidirectional prepreg tape of the upper skin 1 and the lower skin 3 in the present application is consistent or inconsistent, that is, if the laying method of the unidirectional prepreg tape of the upper skin 1 is XYXY, and the laying method of the unidirectional prepreg tape of the lower skin 3 can be XYXY, or a combination of XY and XYX or YXY (X represents longitudinal laying, Y represents transverse laying). This laying method is determined based on the optimal performance under different requirements as the selection criterion.

[0048] It should be noted that when the upper surface 1 and the lower surface 3 are manufactured as the finished product of the battery bottom guard plate, the upper and lower dimensions are consistent. However, during the manufacturing process, when the metal plate 2 is sandwiched between the upper surface 1 and the lower surface 3, they are misaligned up and down to ensure that the hot melt adhesive layers of the upper surface 1 and the lower surface 3 can be fully melted and contacted during the hot melting process. Figure 2 Shown and Figure 3 As shown, Figure 2 This is a schematic diagram of the positional relationship between the upper and lower skins and the metal plates before hot pressing; Figure 3 The schematic diagram of the structure of the battery bottom guard plate after hot pressing. The upper skin 1 and the lower skin 3 are heated to a given temperature and composite pressure until 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 are melted and flow to the surrounding of the metal plate 3, until there is no gap between the three layers of the upper skin 1, the metal plate 2 and the lower skin 3, and the three layers are sealed and flush without protrusions or depressions. Finally, the front and rear battery bottom guard plates are cut and separated. This method is more suitable for mass production and has a simple process.

[0049] It should be noted that, in addition to this, in the prior art of making a battery bottom guard plate, multiple holes are opened on the metal plate 2 for fixing or other purposes. If the four frames of the metal plate 2 are made by the prior art and connected end to end, the bottom guard plate is packaged by combining the upper and lower skins. At this time, the holes on the metal plate 2 need to be sealed separately, which makes the operation cumbersome and there is a risk of poor sealing effect. However, by adopting the technical solution provided by the present application, the metal plate 2 is wrapped by hot-melt adhesive layers of the upper and lower skins and sealed at one time, which reduces many production processes and has better sealing performance.

[0050] The present application also provides a method for preparing a battery bottom guard plate of a fiber-reinforced thermoplastic composite material, comprising steps S1-S3, such as Figure 4 shown.

[0051] S1: A unidirectional prepreg tape formed by impregnating fibers with resin is composited into a first fiber-reinforced composite panel and a second fiber-reinforced composite panel.

[0052] In one embodiment, a continuous glass fiber reinforced polypropylene unidirectional prepreg tape is laid flat in the X and Y directions and compounded by a compounding machine to obtain a first fiber reinforced composite plate. Compounding is performed in the same manner to obtain a second fiber reinforced composite plate. The first fiber reinforced composite plate and the second fiber reinforced composite plate are made by a compounding machine, and the process parameters of the compounding machine are: heating temperature of 200~250℃, cooling temperature of 0~50℃, line speed of 0.5~5m / min, pressure of 0.1~5MPa, and compound gap of 0.5~4mm.

[0053] S2: Laminating a first hot melt adhesive layer of a preset thickness on the first fiber reinforced composite board to form an upper skin; in the same way, laminating a second hot melt adhesive layer on the second fiber reinforced composite board to form a lower skin; wherein, the upper skin and the lower skin are respectively made by laminating the surfaces of the first fiber reinforced composite board and the second fiber reinforced composite board by a laminating machine, and the process parameters of the laminating machine are: heating temperature of 100~300℃, laminating die gap of 0.5~5mm, line speed of 0.5~30m / min, and roller pressure of 0.1~3MPa.

[0054] S3: After the hot melt adhesive layers of the upper and lower surfaces are bonded to the metal plate and melted, the hot melt adhesive layers of the upper and lower surfaces are flowed and wrapped around the metal plate by a given composite pressure until there is no gap and the three-layer structure of the upper surface, the metal plate and the lower surface is flush without protrusions or depressions.

[0055] It should be noted that the upper skin, metal plate and lower skin are processed into the entire battery bottom guard plate by a composite machine. The process parameters of the composite machine are: heating temperature of 220~250℃, cooling temperature of 0~30℃, line speed of 0.5~3m / min, pressure of 0.1~5MPa, and composite gap of 1~4mm.

[0056] Optionally, the resin melt index of the first hot melt adhesive layer or the second hot melt adhesive layer is 50-1000 g / 10 min.

[0057] Optionally, in parts by mass, the material composition of the first hot melt adhesive layer or the second hot melt adhesive layer is: PP resin: 90~98 parts, compatibilizer: 1~5 parts, coupling agent: 0.5~2 parts, antioxidant: 0.5~3 parts.

[0058] In one embodiment, PP resin: 90 parts, compatibilizer: 5 parts, coupling agent: 2 parts, antioxidant: 3 parts In one embodiment, PP resin: 98 parts, compatibilizer: 1 part, coupling agent: 0.5 parts, antioxidant: 0.5 parts.

[0059] In one embodiment, PP resin: 95 parts, compatibilizer: 3 parts, coupling agent: 1 part, antioxidant: 1 part.

[0060] The compatibilizer is one or more of maleic anhydride grafted PP, maleic anhydride grafted PE, maleic anhydride grafted PEO, random ethylene-methyl acrylate-maleic anhydride terpolymer, and the like.

[0061] The coupling agent is one or more of an aminosilane coupling agent, an epoxysilane coupling agent, an acyloxysilane coupling agent, and a vinylsilane coupling agent.

[0062] The antioxidant is one or more of hindered phenol antioxidants, phosphite antioxidants, sulfur antioxidants, and salicylic acid esters.

[0063] Embodiment 1: Product material design: The first fiber-reinforced composite plate of the upper skin adopts continuous fiber-reinforced thermoplastic prepreg tape with 60% by mass glass fiber and 40% by mass polypropylene resin, among which the glass fiber adopts Jushi's EDR17-2400-362A (U). The polypropylene resin adopts Sinopec's EP100N and related compatibilizers and antioxidants, and black masterbatch is added. The compatibilizer is mainly grafted maleic anhydride PP, and the antioxidant is mainly 1010 and 168 system; the upper skin is composed of four layers of 0.25mm thick unidirectional prepreg tapes in an XYXY structure, with a total thickness of 1.0mm.

[0064] The first hot melt adhesive layer: modified polypropylene resin, the melt index is 100g / 10min.

[0065] The second fiber reinforced composite plate of the lower skin uses continuous fiber prepreg tape, which is basically the same as the material used for the upper skin, but the black masterbatch is removed, leaving the original color. In addition, the single layer thickness is 0.2mm, and it is also a four-layer composite, with a total thickness of 0.8mm. Metal plate: high-strength steel plate, 0.8mm thick.

[0066] Product size design: bottom guard plate size 2000*1000mm*3.0mm; metal plate (steel plate) size: 1800*900mm*0.8mm; the first hot melt adhesive layer and the second hot melt adhesive layer (resin film layer): the coating thickness is 0.25mm. After hot pressing and compounding, 0.2mm will remain in the steel plate area, and the remaining 0.05mm will be pressed around the steel plate to form a protective shell for the steel plate. The shell fits tightly with the steel plate without holes or gaps.

[0067] Product manufacturing process route: S1: 0.25 mm thick black continuous glass fiber reinforced polypropylene unidirectional prepreg tape is compounded, and the layering method is XYXY to obtain the first fiber reinforced composite plate; 0.2 mm thick natural color continuous glass fiber reinforced polypropylene unidirectional prepreg tape is compounded, and the layering method is XYXY to obtain the second fiber reinforced composite plate; S2: coating is performed on the first fiber reinforced composite plate and the second fiber reinforced composite plate after the above two composites, and the coating thickness is 0.25 mm to obtain an upper skin and a lower skin respectively; the resin film layer is a modified pp resin, which has good adhesion to the steel plate.

[0068] S3: The upper and lower skins and the steel plate are hot-pressed and composited, with the steel plate in the middle, and the upper and lower skins are bonded to the side of the steel plate as a resin film layer. Composite finished product: During composite production, the line speed, temperature, pressure and gap are adjusted so that the overflow of the resin film layer fills the surrounding of the steel plate. Finished product processing equipment: The working parameter settings of the continuous Teflon composite machine are: heating temperature: 235°C, cooling temperature: 5°C, line speed: 1.5m / min, pressure: 0.5MPa, and composite gap: 3mm. It should be noted that according to the different materials of the hot melt adhesive layer used in the upper skin 1 and the lower skin 3, different heating temperatures, cooling temperatures, line speeds, pressures and composite gaps are set, which can strictly control the generation of bubbles during the melting process and control the flow rate of the high-fluid body, so as to ensure that the hot melt adhesive layer and the metal plate 2 are bonded and formed with high air tightness.

[0069] Embodiment 2: Product material design: The first fiber reinforced composite plate of the upper skin adopts three layers of composite sheets composed of continuous fiber reinforced thermoplastic prepreg. The continuous fiber reinforced thermoplastic prepreg tape adopts 50% by weight of glass fiber and 50% by weight of polypropylene resin, wherein the glass fiber adopts ECER17-1200-612A.

[0070] The first hot melt adhesive layer uses polypropylene resin (650-2 polypropylene material) and related compatibilizers and antioxidants. The compatibilizer is mainly grafted maleic anhydride PP, and the antioxidant is mainly 1010 and 168 systems. The upper skin is composed of three layers of 0.33mm thick unidirectional prepreg tapes in an XYX structure, with a total thickness of 1.0mm.

[0071] The first hot melt adhesive layer or the second hot melt adhesive layer is a resin coating layer, which is a modified polypropylene resin with a melt index of 60g / 10min.

[0072] The second fiber-reinforced composite panel of the lower surface is a fiber-reinforced sheet composed of glass fiber woven cloth and two layers of PP film, with a thickness of 0.5 mm.

[0073] Metal plate: Aluminum plate, 1.0mm thick.

[0074] Product size design: The size of the bottom guard plate is 1500*900mm*3.0mm, the size of the metal plate (aluminum plate) is: 1300*800mm*1.0mm, the first hot melt adhesive layer or the second hot melt adhesive layer is a resin film layer, and the coating thickness is 0.32mm. After hot pressing and compounding, 0.25mm will remain in the steel plate area, and the remaining 0.07mm will be pressed around the steel plate to form a protective shell of the aluminum plate.

[0075] Product manufacturing process route: S1: 0.33mm black continuous glass fiber reinforced polypropylene unidirectional prepreg tape is compounded to obtain the first fiber reinforced composite plate; wherein the 0.33mm thick unidirectional prepreg tape is laid in the manner of XYX. Glass fiber woven cloth and two layers of PP film are compounded to obtain the second fiber reinforced composite plate; the thickness is 0.5mm.

[0076] S2: coating is performed on the first fiber reinforced composite plate and the second fiber reinforced composite plate after the above two composites, and the coating thickness is 0.32 mm to obtain an upper skin and a lower skin respectively; the resin film layer is a modified pp resin, which has good adhesion to the steel plate.

[0077] S3: The upper and lower skins are hot-pressed and laminated with the aluminum plate, with the aluminum plate in the middle and the side of the skin that is attached to the aluminum plate as the resin film layer, to form a composite finished product. During the composite production, the line speed, temperature, pressure and gap are adjusted so that the overflow of the resin film layer fills the surrounding of the aluminum plate. Finished product processing equipment: Working parameter settings of the continuous Teflon laminating machine: Heating temperature (resin film layer, preferably PP as an example): 210℃, cooling temperature: 5℃, line speed: 2m / min, pressure: 0.3MPa, composite gap: 3mm.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present application rather than to limit it. Although the present application has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present application can still be modified or replaced by equivalents, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present application should be included in the scope of protection of the claims of the present application.

Claims

1. A battery bottom guard plate made of fiber-reinforced thermoplastic composite material, characterized in that: include: An upper skin (1), a metal plate (2) and a lower skin (3); The upper surface (1) is formed by laminating a first hot melt adhesive layer (102) on a first fiber reinforced composite plate (101); The lower skin (3) is formed by laminating a second hot melt adhesive layer (202) on a second fiber reinforced composite plate (201); The metal plate (2) is located between the upper surface (1) and the lower surface (3), and is seamlessly wrapped by hot pressing after the first hot melt adhesive layer (102) and the second hot melt adhesive layer (202) are melted.

2. The fiber-reinforced thermoplastic composite battery bottom guard plate according to claim 1, characterized in that: The first fiber-reinforced composite plate (101) contains black masterbatch.

3. The fiber-reinforced thermoplastic composite battery bottom guard plate according to claim 1, characterized in that: The first fiber-reinforced composite plate (101) and the second fiber-reinforced composite plate (201) are both composited from unidirectional prepreg tapes formed by fibers impregnated with thermoplastic resin.

4. The fiber-reinforced thermoplastic composite battery bottom guard plate according to claim 1, characterized in that: The first fiber-reinforced composite plate (101) and the second fiber-reinforced composite plate (201) are both 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.

5. The battery bottom guard plate made of any fiber-reinforced thermoplastic composite material according to claim 1 or claim 3, characterized in that: The plying method of the unidirectional prepreg tape of the first fiber reinforced composite plate (101) is any one of XYXY, YXYX, XY, YX, XYX, and YXY, or any combination thereof.

6. The fiber-reinforced thermoplastic composite battery bottom guard plate according to claim 1, characterized in that: The upper skin (1) and the lower skin (3) are formed by compounding multiple layers of unidirectional prepreg tapes of preset thickness and then coating them with a hot melt adhesive layer on one side.

7. The fiber-reinforced thermoplastic composite battery bottom guard plate according to claim 1, characterized in that: The plying method of the unidirectional prepreg tapes of the upper skin (1) and the lower skin (3) is consistent or inconsistent.

8. The fiber-reinforced thermoplastic composite battery bottom guard plate according to claim 1, characterized in that: The thickness of each layer of the unidirectional prepreg tape of the upper skin (1) and the lower skin (3) is consistent or inconsistent.

9. The battery bottom guard plate made of any fiber-reinforced thermoplastic composite material according to claim 1 or claim 8, characterized in that: The upper surface (1) and the lower surface (3) have the same size and are laid flat with an offset position up and down.

10. A method for preparing a battery bottom guard plate of a fiber-reinforced thermoplastic composite material, characterized in that: include: Composite a first fiber-reinforced composite plate and a second fiber-reinforced composite plate by using a unidirectional prepreg tape formed by impregnating the fiber with resin; The first hot melt adhesive layer of a preset thickness is laminated on the first fiber reinforced composite board to form an upper skin; the second hot melt adhesive layer is laminated on the second fiber reinforced composite board in the same manner to form a lower skin; wherein the upper skin and the lower skin are respectively laminated on the surface of the first fiber reinforced composite board and the second fiber reinforced composite board by a laminating machine, and the process parameters of the laminating machine are: heating temperature of 100-300°C, laminating die gap of 0.5-5mm, line speed of 0.5-30m / min, and roller pressure of 0.1-3MPa; After the hot melt adhesive layers of the upper and lower surfaces are bonded to the metal plate and heated and melted, the hot melt adhesive layers of the upper and lower surfaces are flow-sealed and wrapped around the metal plate by a given composite pressure until there is no gap and the three-layer structure of the upper surface, the metal plate and the lower surface is flush without protrusions or depressions.

11. A method for preparing a battery bottom guard plate made of a fiber-reinforced thermoplastic composite material as claimed in claim 10, characterized in that: The resin melt index of the first hot melt adhesive layer or the second hot melt adhesive layer is 50-1000 g / 10 min.

12. A method for preparing a battery bottom guard plate made of a fiber-reinforced thermoplastic composite material as claimed in claim 11, characterized in that: In parts by mass, the material composition of the first hot melt adhesive layer or the second hot melt adhesive layer is: PP resin: 90-98 parts, compatibilizer: 1-5 parts, coupling agent: 0.5-2 parts, antioxidant: 0.5-3 parts; The compatibilizer is one or more of maleic anhydride grafted PP, maleic anhydride grafted PE, maleic anhydride grafted PEO, random ethylene-methyl acrylate-maleic anhydride terpolymer, etc.; The coupling agent is one or more of an aminosilane coupling agent, an epoxysilane coupling agent, an acyloxysilane coupling agent, and a vinylsilane coupling agent; The antioxidant is one or more of hindered phenol antioxidants, phosphite antioxidants, sulfur antioxidants, and salicylic acid esters.

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