A battery bottom protection plate

Abstract

This application discloses a battery bottom protector, belonging to the technical field of battery bottom protector technology. The battery bottom protector of this application improves the impact strength and deformation resistance of the material by setting a continuous fiber-reinforced thermoplastic resin layer between the metal layer and the honeycomb core layer. Furthermore, the resulting material is lightweight, has good impact and deformation resistance, and is not prone to rust, making it suitable as a battery bottom protector material.

Description

Technical Field

[0001] This application belongs to the field of battery bottom protection plate technology, and specifically relates to a battery bottom protection plate. Background Technology

[0002] In recent years, the development of electric vehicles has attracted widespread attention, and people's concern and curiosity have extended to all aspects, with safety being a major focus. The safety of the battery pack significantly impacts the safety of electric vehicles. Theoretically, adding unlimited structural protection can guarantee safety, but this would result in a bulky and heavy vehicle that is difficult to use. Therefore, we strive for an engineering balance—to reduce weight as much as possible while achieving safety performance. This, of course, places higher demands on materials. Strong, lightweight materials that can insulate against heat and external impacts are crucial for the development of battery packs. Currently, the underbody protection plate, which protects the battery pack from damage by external conditions, is mainly made of metal. To reduce noise, a layer of foam material is usually added between the battery pack and the underbody protection plate. However, foam material is relatively soft and has poor resistance to deformation. When the metal is scraped or subjected to large impact energy, it often undergoes significant deformation, which can also damage the battery pack. Metal underbody protection plates are not only heavy, but their coating is also more prone to corrosion and rust after being scratched, creating weak points. Therefore, a lightweight, highly impact-resistant, and non-deformable / rust-resistant bottom protection plate was developed, making a significant contribution to improving the safety of the battery pack. Summary of the Invention

[0003] Based on the deficiencies of the existing technology, the purpose of this application is to provide a battery bottom protection plate that is lightweight, has high impact strength, and is not easily deformed or rusted, making it suitable as a battery bottom protection plate material.

[0004] To achieve the above objectives, in a first aspect, this application provides a battery bottom protection plate, which includes, from top to bottom, a first continuous fiber reinforced thermoplastic resin layer, a metal layer, a second continuous fiber reinforced thermoplastic resin layer, a honeycomb core layer, and a third continuous fiber reinforced thermoplastic resin layer.

[0005] A continuous fiber-reinforced thermoplastic resin layer is set between the metal layer and the honeycomb core layer. First, the fiber-reinforced thermoplastic resin layer itself has good impact resistance, so as to improve the impact resistance of the battery bottom cover plate. Second, the number of interfaces is increased to improve energy absorption and improve the impact resistance and deformation resistance of the battery bottom cover plate.

[0006] The battery bottom protection plate is lightweight, has good impact and deformation resistance, and is not prone to rust, making it suitable as a battery bottom protection plate material.

[0007] Preferably, the first, second, and third continuous fiber reinforced thermoplastic resin layers are each independent and each contains at least one set of continuous fiber reinforced thermoplastic resin prepreg sheets, with the distribution direction of the continuous fibers in each set of continuous fiber reinforced thermoplastic resin prepreg sheets being mirror-symmetrical. When each layer is not a set of prepreg sheets, the sets in each layer are bonded together by adhesive or adhesive film, creating an interface between the two sets. This increases the number of interfaces, improves energy absorption, and reduces the risk of warping of the first, second, and third continuous fiber reinforced thermoplastic resin layers, thereby improving the impact resistance and deformation resistance of the battery bottom protector.

[0008] Preferably, both the first continuous fiber reinforced thermoplastic resin layer and the third continuous fiber reinforced thermoplastic resin layer comprise a set of continuous fiber reinforced thermoplastic resin prepreg sheets.

[0009] Preferably, the second continuous fiber reinforced thermoplastic resin layer comprises two sets of continuous fiber reinforced thermoplastic resin prepreg sheets. More preferably, in the second continuous fiber reinforced thermoplastic resin layer, the two sets of continuous fiber reinforced thermoplastic resin prepreg sheets are bonded together by adhesive or by adhesive film. This results in a greater number of interfaces, increased energy absorption, and better impact and deformation resistance of the battery bottom protector. Furthermore, the preparation method of the battery bottom protector is also simpler.

[0010] Preferably, the number of continuous fiber reinforced thermoplastic resin prepreg sheets in each group is even, so as to reduce the risk of warping of each group of continuous fiber reinforced thermoplastic resin prepreg sheets and make the impact resistance and deformation resistance of the battery bottom cover better.

[0011] Preferably, in each group of continuous fiber reinforced thermoplastic resin prepreg sheets, the number of continuous fiber reinforced thermoplastic resin prepreg sheets is two or more, such as a range of two, four, six, eight, ten or more layers. More preferably, in each group of continuous fiber reinforced thermoplastic resin prepreg sheets, the number of continuous fiber reinforced thermoplastic resin prepreg sheets is four to eight layers, such as a range of four, six, eight or more layers.

[0012] When the number of continuous fiber reinforced thermoplastic resin prepreg sheets in each group is more than 2 layers, especially when the number of continuous fiber reinforced thermoplastic resin prepreg sheets in each group is 4 to 8 layers, the warpage risk of each group of continuous fiber reinforced thermoplastic resin layers is lower, and the impact resistance and deformation resistance of the battery bottom protector are better.

[0013] Preferably, the angle difference between the surface and central axis (i.e., the upper surface to the central axis and the lower surface to the central axis) of each group of continuous fiber reinforced thermoplastic resin prepreg sheets, and the angle difference between the continuous fiber directions of adjacent layers of continuous fiber reinforced thermoplastic resin prepreg sheets, is 15° to 95°. By setting the angle difference between the surface and central axis of each group of continuous fiber reinforced thermoplastic resin prepreg sheets, and the angle difference between the continuous fiber directions of adjacent layers of continuous fiber reinforced thermoplastic resin prepreg sheets, within the range of 15° to 95°, such as 15°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, 90°, 95°, or any two of the above, the anisotropy of the battery bottom protection plate is improved, and the impact resistance is enhanced.

[0014] The thermoplastic resin in the continuous fiber reinforced thermoplastic resin prepreg can be any type commonly used in the field of battery bottom protectors. Preferably, the thermoplastic resin in each continuous fiber reinforced thermoplastic resin prepreg includes at least one of polypropylene, polyethylene, ABS, PA, PC, PET, etc. More preferably, the thermoplastic resin in each continuous fiber reinforced thermoplastic resin prepreg includes polypropylene.

[0015] Preferably, the thickness of each continuous fiber reinforced thermoplastic resin prepreg is 0.10~0.60 mm, such as 0.10 mm, 0.15 mm, 0.20 mm, 0.25 mm, 0.30 mm, 0.35 mm, 0.40 mm, 0.45 mm, 0.50 mm, 0.55 mm, 0.60 mm or any two of the above.

[0016] Preferably, the total thickness of each group of continuous fiber reinforced thermoplastic resin prepreg sheets (i.e., the sum of the thicknesses of the internal continuous fiber reinforced thermoplastic resin prepreg sheets in each group of continuous fiber reinforced thermoplastic resin prepreg sheets) is 0.2~2mm, such as 0.2mm, 0.5mm, 0.7mm, 1mm, 1.2mm, 1.5mm, 1.7mm, 2mm or any two of the above.

[0017] Preferably, the metal layer is bonded to the first continuous fiber reinforced thermoplastic resin layer and the second continuous fiber reinforced thermoplastic resin layer by an adhesive film.

[0018] Preferably, the thickness of the metal layer is 0.28mm to 4.0mm, such as 0.28mm, 0.30mm, 0.50mm, 0.70mm, 1.0mm, 1.5mm, 2.0mm, 2.5mm, 3.0mm, 3.5mm, 4.0mm or any two of the above.

[0019] Preferably, the thickness of the honeycomb core layer is 5mm to 25mm, such as 5mm, 7mm, 10mm, 13mm, 15mm, 17mm, 20mm, 22mm, 25mm or any combination thereof.

[0020] Preferably, the thickness of the battery bottom cover plate is 6~40mm.

[0021] Preferably, the metal layer comprises a metal substrate and a plating layer disposed on the surface of the metal substrate.

[0022] More preferably, the metal matrix includes at least one of steel plate, steel strip and steel mesh.

[0023] More preferably, the material of the coating includes at least one selected from metallic zinc, zinc-iron alloy, and zinc-magnesium alloy, and the weight of the coating is 20 g / m³. 2 ~300 g / m 2 The zinc content is 10% to 100% by mass. Controlling the zinc content in the coating within the range of 10% to 100% by mass can improve corrosion resistance.

[0024] Preferably, the material of the honeycomb core layer is a thermoplastic resin. The material of the honeycomb core layer preferably includes at least one of polypropylene and polyethylene, and more preferably polypropylene.

[0025] Preferably, in the honeycomb core layer, the wall thickness of the honeycomb core is 0.2~1.0 mm, and the bulk density of the honeycomb core is 70 kg / m³. 3 ~200 kg / m 3 .

[0026] Preferably, the honeycomb core layer is connected to the second continuous fiber reinforced thermoplastic resin layer and the third continuous fiber reinforced thermoplastic resin layer by hot-pressing composite. Preferably, the hot-pressing composite loss is controlled within 2 mm, such as 2 mm, 1.8 mm, 1.6 mm, 1.4 mm, 1.2 mm, 1 mm, 0.8 mm, 0.6 mm, 0.4 mm, 0.2 mm, 0.1 mm, or any combination thereof.

[0027] Secondly, this application provides an application of the aforementioned battery bottom protector in a battery bottom protector. Typically, when the battery bottom protector is used in a battery bottom protector, the honeycomb core layer is closer to the ground than its metal layer.

[0028] Compared with the prior art, the beneficial effects of this application are as follows:

[0029] (1) This application provides a continuous fiber-reinforced thermoplastic resin layer between the metal layer and the honeycomb core layer. The fiber-reinforced thermoplastic resin layer itself has good impact resistance, which improves the impact resistance of the battery bottom protection plate. It also increases the number of interfaces, improves energy absorption, and improves the impact resistance and deformation resistance of the battery bottom protection plate.

[0030] (2) The battery bottom protection plate of this application is lightweight, has good impact resistance and deformation resistance, and is not easy to rust, making it suitable as a battery bottom protection plate material. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of the battery bottom cover plate in Example 1. 1-First continuous fiber reinforced thermoplastic resin layer, 2-Metal layer, 3-Second continuous fiber reinforced thermoplastic resin layer, 4-Honeycomb core layer, 5-Third continuous fiber reinforced thermoplastic resin layer, 31-First group of continuous fiber reinforced thermoplastic resin prepreg sheets, 32-Second group of continuous fiber reinforced thermoplastic resin prepreg sheets. Detailed Implementation

[0032] To better illustrate the purpose, technical solutions, and advantages of this application, the following description, in conjunction with specific embodiments and comparative examples, aims to provide a detailed understanding of the content of this application, rather than limiting it. All other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of this application. Unless otherwise specified, the experimental reagents and instruments involved in the implementation of this application are commonly used reagents and instruments. In this application, the technical features described in an open-ended manner include both closed-ended technical solutions composed of the listed features and open-ended technical solutions that include the listed features.

[0033] Example 1

[0034] This embodiment provides a battery bottom protection plate with a thickness of 12mm. From top to bottom, it includes a first continuous fiber reinforced thermoplastic resin layer 1, a metal layer 2, a second continuous fiber reinforced thermoplastic resin layer 3, a honeycomb core layer 4, and a third continuous fiber reinforced thermoplastic resin layer 5.

[0035] Both the first continuous fiber reinforced thermoplastic resin layer 1 and the third continuous fiber reinforced thermoplastic resin layer 5 include a set of continuous fiber reinforced thermoplastic resin prepreg sheets.

[0036] The second continuous fiber reinforced thermoplastic resin layer 3 includes, from top to bottom, a first group of continuous fiber reinforced thermoplastic resin prepreg sheets 31 and a second group of continuous fiber reinforced thermoplastic resin prepreg sheets 32, which are connected by adhesive.

[0037] The total thickness of each of the above groups of continuous fiber reinforced thermoplastic resin prepreg sheets is 1.2 mm, and each is obtained by hot pressing and composite of 8 layers of continuous fiber reinforced thermoplastic resin prepreg sheets with a layup design of 0° / 25° / 50° / 75° / 75° / 50° / 25° / 0°. The thickness of the continuous fiber reinforced thermoplastic resin prepreg sheets used is the same, which is 0.15 mm, and the thermoplastic resin contained is polypropylene.

[0038] Metal layer 2 is a galvanized steel sheet, with a zinc content of 100% by mass and a coating weight of 180g / m². 2 The thickness of the galvanized steel plate is 1.2mm, and the metal layer is bonded to the first continuous fiber reinforced thermoplastic resin layer 1 and the second continuous fiber reinforced thermoplastic resin layer 3 by an adhesive film.

[0039] The honeycomb core layer 4 is made of polypropylene, with a wall thickness of 0.7 mm and a bulk density of 120 kg / m³. 3 It has a thickness of 6mm and is connected to the second continuous fiber reinforced thermoplastic resin layer 3 and the third continuous fiber reinforced thermoplastic resin layer 5 by hot pressing.

[0040] Example 2

[0041] This embodiment provides a battery bottom protection plate, which differs from the battery bottom protection plate in embodiment 1 in that:

[0042] The second continuous fiber reinforced thermoplastic resin layer 3 consists of three groups of continuous fiber reinforced thermoplastic resin prepreg sheets, which are connected by adhesive. In these three groups, the total thickness of each group of unidirectional continuous fiber reinforced thermoplastic resin prepreg sheets is 0.8 mm, and they are obtained by hot pressing and bonding of 8 layers of continuous fiber reinforced thermoplastic resin prepreg sheets with a layup design of 0° / 25° / 50° / 75° / 75° / 50° / 25° / 0°. The thickness of the continuous fiber reinforced thermoplastic resin prepreg sheets used is the same, which is 0.1 mm.

[0043] Example 3

[0044] This embodiment provides a battery bottom protection plate, which differs from the battery bottom protection plate in embodiment 1 in that:

[0045] The second continuous fiber reinforced thermoplastic resin layer 3 is a group of continuous fiber reinforced thermoplastic resin prepreg sheets. The total thickness of this group of continuous fiber reinforced thermoplastic resin prepreg sheets is 2.4 mm. It is obtained by hot pressing and bonding of 8 layers of continuous fiber reinforced thermoplastic resin prepreg sheets with a layup design of 0° / 25° / 50° / 75° / 75° / 50° / 25° / 0°. The thickness of the continuous fiber reinforced thermoplastic resin prepreg sheets used is the same, which is 0.3 mm.

[0046] Example 4

[0047] This embodiment provides a battery bottom protection plate, which differs from the battery bottom protection plate in embodiment 1 in that:

[0048] The thickness of the first group of continuous fiber reinforced thermoplastic resin prepreg sheets 31 and the second group of continuous fiber reinforced thermoplastic resin prepreg sheets 32 is 1.2 mm. They are both obtained by hot pressing and composite of 4 layers of continuous fiber reinforced thermoplastic resin prepreg sheets with a layup design of 25° / 50° / 50° / 25° from top to bottom. The thickness of the continuous fiber reinforced thermoplastic resin prepreg sheets used is the same, which is 0.3 mm.

[0049] Example 5

[0050] This embodiment provides a battery bottom protection plate. The difference between the battery bottom protection plate in this embodiment and that in embodiment 4 is:

[0051] The first group of continuous fiber reinforced thermoplastic resin prepreg sheets 31 has a thickness of 1.2 mm and is obtained by hot pressing and bonding 4 layers of continuous fiber reinforced thermoplastic resin prepreg sheets in a layup design of 25° / 25° / 50° / 50° from top to bottom. The thickness of the continuous fiber reinforced thermoplastic resin prepreg sheets used is the same, which is 0.3 mm.

[0052] Example 6

[0053] This embodiment provides a battery bottom protection plate. The difference between the battery bottom protection plate in this embodiment and that in embodiment 4 is:

[0054] The second group of continuous fiber reinforced thermoplastic resin layers 32 has a thickness of 1.2 mm and is obtained by hot pressing and bonding of 4 layers of continuous fiber reinforced thermoplastic resin prepreg sheets in a layup design of 25° / 25° / 50° / 50° from top to bottom. The thickness of the continuous fiber reinforced thermoplastic resin prepreg sheets used is the same, which is 0.3 mm.

[0055] Example 7

[0056] This embodiment provides a battery bottom protection plate. The difference between the battery bottom protection plate in this embodiment and that in embodiment 4 is:

[0057] The thickness of the first group of continuous fiber reinforced thermoplastic resin layers 31 and the second group of continuous fiber reinforced thermoplastic resin layers 32 is 1.2 mm. They are both obtained by hot pressing and bonding of 6 layers of continuous fiber reinforced thermoplastic resin prepreg sheets in a layup design of 25° / 50° / 25° / 25° / 50° / 25° from top to bottom. The thickness of the continuous fiber reinforced thermoplastic resin prepreg sheets used is the same, which is 0.2 mm.

[0058] Comparative Example 1

[0059] This comparative example provides a battery bottom protection plate, which differs from Example 1 in that it does not contain the second continuous fiber reinforced thermoplastic resin layer 3, and the metal layer 2 and the honeycomb core layer 4 are bonded together by an adhesive film.

[0060] The thicknesses of the first continuous fiber reinforced thermoplastic resin layer 1, the metal layer 2, the honeycomb core layer 4, and the third continuous fiber reinforced thermoplastic resin layer 5 are all the same as in Example 1.

[0061] The following performance tests were conducted on the battery bottom protection plates of the above embodiments and comparative examples:

[0062] Drop hammer impact strength test: The test was conducted in accordance with ASTM D7136-2005, with a hammer diameter d=16mm and a base support area r=30mm (circular). The maximum drop hammer impact strength corresponding to the breakage of the plate and the amount of deformation under the maximum drop hammer impact strength were recorded.

[0063] Table 1

[0064]

[0065] As can be seen from the above data, the battery bottom protection plate of this application has good impact resistance, with a maximum drop hammer impact strength of over 300J.

[0066] Comparative Example 1 showed a deviation in the material's impact resistance because a continuous fiber-reinforced thermoplastic resin layer was not provided between the metal layer and the honeycomb core layer.

[0067] A comparison of Examples 1-3 shows that when the number of continuous fiber reinforced thermoplastic resin prepreg sheets in the second continuous fiber reinforced thermoplastic resin layer is more than 2, the material has better impact resistance.

[0068] A comparison of Examples 4-6 shows that when the distribution direction of the continuous fibers in each group of continuous fiber reinforced thermoplastic resin prepregs in the second continuous fiber reinforced thermoplastic resin layer is mirror-symmetrical, the material has better impact resistance.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit the scope of protection of this application. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the substance and scope of the technical solutions of this application.

Claims

1. A battery undertray characterized by, From top to bottom, it includes a first continuous fiber reinforced thermoplastic resin layer, a metal layer, a second continuous fiber reinforced thermoplastic resin layer, a honeycomb core layer, and a third continuous fiber reinforced thermoplastic resin layer; the first continuous fiber reinforced thermoplastic resin layer, the second continuous fiber reinforced thermoplastic resin layer, and the third continuous fiber reinforced thermoplastic resin layer are each independent and each contains at least one set of continuous fiber reinforced thermoplastic resin prepreg sheets.

2. The battery undertray of claim 1, wherein, The distribution direction of continuous fibers in each group of continuous fiber reinforced thermoplastic resin prepregs is mirror symmetrical.

3. The battery undertray of claim 1, wherein, The first continuous fiber reinforced thermoplastic resin layer and the third continuous fiber reinforced thermoplastic resin layer each contain a set of continuous fiber reinforced thermoplastic resin prepreg sheets, and the second continuous fiber reinforced thermoplastic resin layer contains two sets of continuous fiber reinforced thermoplastic resin prepreg sheets.

4. The battery undertray of claim 3, wherein, In the second continuous fiber reinforced thermoplastic resin layer, the two sets of continuous fiber reinforced thermoplastic resin prepreg sheets are bonded together by adhesive or by adhesive film.

5. The battery undertray of claim 1, wherein, In each group of continuous fiber reinforced thermoplastic resin prepreg sheets, the number of continuous fiber reinforced thermoplastic resin prepreg sheets is always an even number.

6. The battery undertray of claim 1, wherein, At least one of the following conditions must be met: A. The angle difference between the surface of each group of continuous fiber reinforced thermoplastic resin prepreg sheets and the central axis, and between adjacent layers of continuous fiber reinforced thermoplastic resin prepreg sheets, is 15°~95°. B. The thickness of each continuous fiber reinforced thermoplastic resin prepreg is 0.10~0.60mm; C. The total thickness of each group of continuous fiber reinforced thermoplastic resin prepreg sheets is 0.2~2mm.

7. The battery undertray of claim 1, wherein, The metal layer is bonded to the first continuous fiber reinforced thermoplastic resin layer and the second continuous fiber reinforced thermoplastic resin layer by an adhesive film.

8. The battery undertray of claim 1, wherein, At least one of the following conditions must be met: S1. The metal layer includes a metal substrate and a plating layer disposed on the surface of the metal substrate; S2, in the honeycomb core layer, the wall thickness of the honeycomb core is 0.2-1.0 mm, and the bulk density of the honeycomb core is 70 kg / m 3 ~200 kg / m 3 ; S3. The honeycomb core layer is connected to the second continuous fiber reinforced thermoplastic resin layer and the third continuous fiber reinforced thermoplastic resin layer by hot pressing composite method. S4. The thickness of the metal layer is 0.28 mm to 4.0 mm. S5. The thickness of the honeycomb core layer is 5mm~25mm; S6. The thickness of the battery bottom protection plate is 6~40mm.

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