Battery pack bottom protection plate and battery pack with bottom protection

Abstract

The utility model discloses a battery pack bottom protection plate and a battery pack with a bottom protection function, and belongs to the technical field of electric automobile battery packs. The battery pack bottom protection plate sequentially comprises an inner surface layer, a first hot melt adhesive bonding layer, an aramid fabric layer, a second hot melt adhesive bonding layer, a polycarbonate layer, a third hot melt adhesive bonding layer and an outer surface layer, the inner surface layer is selected from a continuous fiber reinforced thermoplastic sheet, a glass fiber fabric reinforced thermoplastic sheet, a long fiber reinforced thermoplastic sheet or a chopped fiber reinforced thermoplastic sheet; the outer surface layer is selected from a continuous fiber reinforced thermoplastic sheet, a glass fiber fabric reinforced thermoplastic sheet, a long fiber reinforced thermoplastic sheet or a chopped fiber reinforced thermoplastic sheet. The battery pack bottom protection plate is made of the composite material without a metal layer, and the aramid fabric layer and the polycarbonate layer are combined for use, so that the weight of the bottom protection plate is remarkably reduced while a good anti-impact effect is realized, the energy efficiency of a battery is improved, and the endurance mileage of an electric automobile is increased.

Description

Technical Field

[0001] The utility model relates to the technical field of electric vehicle battery packs, in particular to a battery pack bottom guard plate and a bottom-protected battery pack. Background Art

[0002] The battery pack bottom guard plate is an important component in electric vehicles to protect the battery pack from external physical impact and environmental corrosion. Its design and material selection directly affect the safety and service life of the battery.

[0003] The existing battery pack bottom guard plate is mainly made of metal plate (steel plate or aluminum alloy plate). Although it can protect the battery from slight to moderate bottom impact, the metal plate is heavy and energy-intensive, which seriously reduces the cruising range.

[0004] In order to solve the weight problem of the above-mentioned battery pack bottom guard plate, people have tried to prepare composite materials for the battery pack bottom guard plate, such as Chinese patent CN202121283364.7, which discloses a battery pack bottom guard plate, which is composed of two glass fiber layers and a metal layer sandwiched between the two glass fiber layers. The bottom guard plate adopts a combination of a high-strength glass fiber layer and a metal layer with high plastic deformation performance, so that the bottom guard plate has a good ability to resist external strong intermittent and high-speed impacts, so as to protect the battery pack from damage due to external bumps, bottoming and other working conditions to the greatest extent. At the same time, the glass fiber layer itself has good corrosion resistance, aging resistance, acid and alkali resistance, and oil resistance. By coating the metal layer surface with two layers of glass fiber layers, the metal surface treatment process can be omitted, which improves the corrosion resistance of the bottom guard plate and saves the cost of the surface treatment process of the bottom guard plate. In addition, the use of this lightweight material can reduce the overall weight of the bottom guard plate, increase the energy density of the battery pack, and reduce the energy consumption of the whole vehicle. However, this structure still requires the use of metal layers, which is still very heavy and affects the energy consumption and range of the vehicle. Utility Model Content

[0005] In view of this, the technical problem to be solved by the utility model is to provide a battery pack bottom guard plate and a battery pack with bottom protection. The battery pack bottom guard plate has the advantages of light weight, high strength, impact resistance, corrosion resistance, and flame retardancy, thereby improving the safety and durability of the battery pack.

[0006] In order to achieve the above purpose, the technical solution adopted by the utility model is as follows:

[0007] The utility model provides a battery pack bottom guard plate, which sequentially comprises an inner surface layer, a first hot melt adhesive layer, an aramid fabric layer, a second hot melt adhesive layer, a polycarbonate layer, a third hot melt adhesive layer, and an outer surface layer;

[0008] The inner surface layer is the contact surface with the battery pack, and the outer surface layer is the appearance surface;

[0009] The inner surface layer is selected from a continuous fiber reinforced thermoplastic sheet, a glass fiber fabric reinforced thermoplastic sheet, a long fiber reinforced thermoplastic sheet or a chopped fiber reinforced thermoplastic sheet;

[0010] The outer surface layer is selected from a continuous fiber reinforced thermoplastic sheet, a glass fiber fabric reinforced thermoplastic sheet, a long fiber reinforced thermoplastic sheet or a short fiber reinforced thermoplastic sheet.

[0011] The above-mentioned continuous fiber reinforced thermoplastic sheet, glass fiber fabric reinforced thermoplastic sheet, long fiber reinforced thermoplastic sheet or short fiber reinforced thermoplastic sheet have good tolerance and are not easy to corrode, so that the battery pack bottom guard plate has good corrosion resistance, aging resistance and high temperature resistance.

[0012] In the utility model, the first hot melt adhesive layer and the second hot melt adhesive layer completely infiltrate the aramid fabric layer therebetween and have good adhesion. When impacted, the aramid fabric layer is not easy to disperse and form an impact gap.

[0013] Preferably, in the present invention, the first hot melt adhesive layer, the second hot melt adhesive layer and the third hot melt adhesive layer are independently selected from polyamide hot melt adhesive film adhesive layer, copolyester hot melt adhesive film adhesive layer, polyurethane hot melt adhesive film adhesive layer or polyethylene hot melt adhesive film adhesive layer.

[0014] The aramid fabric layer has high specific strength and high specific modulus, and can provide excellent tensile and deformation resistance at a lighter weight, which enables the battery pack bottom guard plate of the structure to effectively absorb and disperse impact energy when impacted, thereby preventing structural damage caused by energy concentration.

[0015] Moreover, because the molecular chain of the aramid fabric in the aramid fabric layer contains a large number of benzene ring structures, the battery pack bottom guard plate is not easy to break at high temperatures and can form a stable carbonized layer. This carbonized layer has good thermal insulation properties and can prevent heat from being further transferred to the interior of the fiber, thereby playing a flame retardant role. The battery pack bottom guard plate can meet the UL-94V0 flame retardant requirements.

[0016] In addition, the benzene ring structure can absorb heat, slow down the temperature rise of the surrounding environment, and inhibit the spread of flames.

[0017] Preferably, in the present invention, the aramid fabric layer is selected from a para-aramid fabric layer;

[0018] Preferably, the texture of the para-aramid fabric layer is selected from plain weave, twill weave or satin weave.

[0019] Preferably, the surface density of the para-aramid fabric layer is 100-500 g / m 2More preferably 150-300g / m 2 ; More preferably 200-250g / m 2 In some specific embodiments of the present invention, 200 g / m 2 .

[0020] The polycarbonate (PC) layer in the battery pack bottom guard plate enables the battery pack bottom guard plate to absorb and disperse energy when impacted, and is not easily broken. This is because the main chain of the polycarbonate molecular structure is connected by a soft carbonate chain and a rigid benzene ring, which gives the polycarbonate (PC) layer both hard and soft properties.

[0021] The utility model adopts an aramid fabric layer and a polycarbonate (PC) layer to form a multi-layer composite battery pack bottom guard plate, which together enhances the impact resistance of the battery pack bottom guard plate, effectively prevents impact objects from penetrating and damaging, improves the safety of the battery, and prolongs the service life.

[0022] Preferably, the thickness of the polycarbonate layer is 1.0-5.0 mm; more preferably 3.0-4.0 mm; further preferably 3.0 mm.

[0023] Preferably, the thickness of the inner surface layer is 0.5-2.0 mm; more preferably 0.6-1.5 mm; further preferably 0.8 mm.

[0024] Preferably, the thickness of the outer surface layer is 1.0-3.0 mm; more preferably 1.5-2.0 mm; further preferably 1.6 mm.

[0025] Preferably, the thickness of the first hot melt adhesive layer and the second hot melt adhesive layer are independently selected from 80-200 μm, more preferably 90-150 μm, and preferably 100 μm in some specific embodiments of the present invention.

[0026] Preferably, the thickness of the third hot melt adhesive layer is 50-200 μm, more preferably 60-150 μm, and in some specific embodiments of the present invention, preferably 75 μm.

[0027] The battery pack bottom guard plate described in the utility model has a certain molding flexibility and can be designed to obtain the required geometric structure, such as flange edge, protrusion or reinforcing rib structure, etc., thereby optimizing the overall design of the battery pack with the bottom guard plate.

[0028] More preferably, the battery pack bottom guard plate includes, from inside to outside, a first continuous fiber reinforced thermoplastic sheet layer, a first polyamide hot melt adhesive film bonding layer, a plain para-aramid fabric layer, a second polyamide hot melt adhesive film bonding layer, a polycarbonate layer, a third polyamide hot melt adhesive film bonding layer, and a second continuous fiber reinforced thermoplastic sheet layer.

[0029] Further preferably, the surface density of the plain weave para-aramid fabric layer is 200 g / m 2 ;

[0030] The thickness of the polycarbonate layer is 3.0 mm;

[0031] The thickness of the first continuous fiber reinforced thermoplastic sheet layer is 0.8 mm;

[0032] The thickness of the second continuous fiber reinforced thermoplastic sheet layer is 1.6 mm;

[0033] The thickness of the first polyamide hot melt adhesive film adhesive layer and the second polyamide hot melt adhesive film adhesive layer is 100 μm;

[0034] The thickness of the third polyamide hot melt adhesive film bonding layer is 75 μm.

[0035] The utility model also provides a bottom-protected battery pack, comprising a battery pack and a battery pack bottom guard plate arranged at the bottom of the battery pack;

[0036] The battery pack bottom protective plate is selected from the above-mentioned battery pack bottom protective plates.

[0037] The configuration includes but is not limited to fixing the battery pack bottom guard plate to the bottom of the battery pack by bolts.

[0038] Compared with the prior art, the battery pack bottom guard plate provided by the utility model includes an inner surface layer, a first hot melt adhesive layer, an aramid fabric layer, a second hot melt adhesive layer, a polycarbonate layer, a third hot melt adhesive layer, and an outer surface layer in sequence; the inner surface layer is selected from continuous fiber reinforced thermoplastic sheet, glass fiber fabric reinforced thermoplastic sheet, long fiber reinforced thermoplastic sheet or short fiber reinforced thermoplastic sheet; the outer surface layer is selected from continuous fiber reinforced thermoplastic sheet, glass fiber fabric reinforced thermoplastic sheet, long fiber reinforced thermoplastic sheet or short fiber reinforced thermoplastic sheet. The battery pack bottom guard plate described in the utility model is a composite material without a metal layer. It adopts an aramid fabric layer and a polycarbonate (PC) layer in combination, which achieves a good impact resistance effect while significantly reducing the weight of the bottom guard plate, improving the energy efficiency of the battery and the cruising range of the electric vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a structural schematic diagram of the battery pack bottom guard plate of the present utility model. DETAILED DESCRIPTION

[0040] In order to further illustrate the present invention, the battery pack bottom guard plate and the bottom-protected battery pack provided by the present invention are described in detail below in conjunction with the embodiments.

[0041] Figure 1 The battery pack bottom guard plate prepared by the utility model has a structure as follows Figure 1 As shown, 1 is the inner surface layer, 2 is the first hot melt adhesive layer, 3 is the aramid fabric layer, 4 is the second hot melt adhesive layer, 5 is the polycarbonate layer, 6 is the third hot melt adhesive layer, and 7 is the outer surface layer.

[0042] Example 1

[0043] The battery pack bottom guard plate is made of multiple layers of materials through hot pressing and compounding by a composite material continuous lamination machine (equipment manufacturer: Mayer Company, Germany, equipment model: KFK-P-1800);

[0044] The composite material continuous lamination machine consists of five parts: automatic feeding system, heating section, central pressure roller, cooling section and automatic cutting machine.

[0045] The automatic loading system includes a conveyor belt, an upper unwinding device, a lower unwinding device, an automatic loading robot 1, an automatic loading robot 2, and an automatic loading robot 3 (after startup, the automatic loading robots 1, 2, and 3 are arranged in sequence along the running direction of the equipment).

[0046] Before starting the machine, the first polyamide hot melt adhesive film bonding layer, the aramid fabric layer, and the second polyamide hot melt adhesive film bonding layer are sequentially installed on the three unwinding rollers of the upper unwinding device; the third polyamide hot melt adhesive film bonding layer is installed on the unwinding roller of the lower unwinding device.

[0047] The equipment is turned on, and the conveyor belt linear speed is set to 4.0m / min. The conveyor belt starts, and the automatic feeding robot clamps the second continuous fiber reinforced thermoplastic sheet with a thickness of 1.6mm, places it on the conveyor belt and transports it forward. The lower unwinding mechanism is started to overlap the third polyamide hot melt adhesive film bonding layer on the second continuous fiber reinforced thermoplastic sheet, and then the automatic feeding robot 2 clamps the polycarbonate layer and places it on the above material, and continues to transport it forward; the upper unwinding device is started to successively overlap the second polyamide hot melt adhesive film bonding layer, the aramid fabric layer (purchased from Taihe New Materials Group Co., Ltd.), and the first polyamide hot melt adhesive film bonding layer on top of the PC board, and finally the automatic feeding robot 3 clamps the first continuous fiber reinforced thermoplastic sheet layer (inner surface layer) with a thickness of 0.8mm and places it on top of the above material to complete the material overlapping and transport it into the heating section of the equipment along the conveyor belt.

[0048] The temperature of the heating section is set at 220℃. After the polyamide hot melt adhesive layer in the multi-layer material is heated and melted, it is pressed by the central pressure roller to achieve full infiltration and bonding. The pressure of the central pressure roller is set to 4.0Mpa. The cooling zone is cooled by circulating water. The water temperature is controlled at 10℃ by a chiller. After the bonded material is fully cooled and solidified, it is cut into shape by an automatic cutting machine to obtain the final battery pack bottom guard plate.

[0049] The battery pack bottom guard plate includes, from inside to outside, a first continuous fiber reinforced thermoplastic sheet layer (inner surface layer) with a thickness of 0.8 mm, a first polyamide hot melt adhesive film bonding layer (first hot melt adhesive bonding layer) with a thickness of 100 μm, and a surface density of 200 g / m 2 A plain woven para-aramid fabric layer (aramid fabric layer), a second polyamide hot melt adhesive film bonding layer (second hot melt adhesive bonding layer) with a thickness of 100 μm, a polycarbonate layer with a thickness of 3.0 mm (polycarbonate layer), a third polyamide hot melt adhesive film bonding layer (third hot melt adhesive bonding layer) with a thickness of 75 μm, and a second continuous fiber reinforced thermoplastic sheet layer (outer surface layer) with a thickness of 1.6 mm.

[0050] Finally, the performance test of the battery pack bottom guard plate was carried out. The impact test was carried out in accordance with the bottom impact test method provided in 8.2.16 of GB 38031-Safety Requirements for Power Batteries for Electric Vehicles to evaluate the protective effect of the battery pack bottom guard plate on the battery pack. The energy of mild, moderate and severe impacts were 120J, 300J and 400J respectively. The experimental requirement was that after the battery pack with the battery pack bottom guard plate installed was subjected to the impact test, the impact deformation of the aluminum shell of the battery pack tray was ≤4mm.

[0051] The results are shown in Table 1, which shows the density, impact resistance and flame retardancy of the battery pack bottom guard plate.

[0052] Table 1 Density, impact resistance and flame retardancy of the battery pack bottom guard plate

[0053] Serial number Test items Test Results 1 density <![CDATA[1450g / cm 3 ]]> 2 Low impact - 120J Deformation: 0.96mm 3 Medium impact - 300J Deformation: 1.85mm 4 Severe impact - 400J Deformation: 3.75mm 5 Flame retardant UL-94 V0

[0054] The results in Table 1 show that the density of the battery pack bottom guard plate prepared by the utility model is much lower than that of the bottom guard plate made of metal. In addition, the impact resistance meets the requirements of moderate and severe impact tests.

[0055] The above embodiments are only used to help understand the method and core idea of ​​the utility model. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made to the utility model without departing from the principle of the utility model, and these improvements and modifications also fall within the scope of protection of the claims of the utility model.

Claims

1. A battery pack bottom guard plate, characterized in that: It includes, in sequence, an inner surface layer, a first hot melt adhesive layer, an aramid fabric layer, a second hot melt adhesive layer, a polycarbonate layer, a third hot melt adhesive layer, and an outer surface layer; The inner surface layer is selected from a continuous fiber reinforced thermoplastic sheet, a glass fiber fabric reinforced thermoplastic sheet, a long fiber reinforced thermoplastic sheet or a chopped fiber reinforced thermoplastic sheet; The outer surface layer is selected from a continuous fiber reinforced thermoplastic sheet, a glass fiber fabric reinforced thermoplastic sheet, a long fiber reinforced thermoplastic sheet or a short fiber reinforced thermoplastic sheet.

2. The battery pack bottom guard plate according to claim 1, characterized in that: The first hot melt adhesive layer, the second hot melt adhesive layer and the third hot melt adhesive layer are independently selected from polyamide hot melt adhesive film adhesive layer, copolyester hot melt adhesive film adhesive layer, polyurethane hot melt adhesive film adhesive layer or polyethylene hot melt adhesive film adhesive layer.

3. The battery pack bottom guard plate according to claim 1, characterized in that: The aramid fabric layer is selected from a para-aramid fabric layer; The texture of the para-aramid fabric layer is selected from plain weave, twill weave or satin weave.

4. The battery pack bottom guard plate according to claim 1, characterized in that: The thickness of the polycarbonate layer is 1.0-5.0 mm.

5. The battery pack bottom guard plate according to claim 1, characterized in that: The thickness of the inner surface layer is 0.5-2.0 mm; The thickness of the outer surface layer is 1.0-3.0 mm.

6. The battery pack bottom guard plate according to claim 1, characterized in that: The thickness of the first hot melt adhesive layer and the second hot melt adhesive layer are independently selected from 80-200 μm; The thickness of the third hot melt adhesive layer is 50-200 μm.

7. The battery pack bottom guard plate according to any one of claims 1 to 6, characterized in that: It includes in sequence a first continuous fiber reinforced thermoplastic sheet layer, a first polyamide hot melt adhesive film bonding layer, a plain para-aramid fabric layer, a second polyamide hot melt adhesive film bonding layer, a polycarbonate layer, a third polyamide hot melt adhesive film bonding layer, and a second continuous fiber reinforced thermoplastic sheet layer.

8. The battery pack bottom guard plate according to claim 7, characterized in that: The thickness of the polycarbonate layer is 3.0 mm; The thickness of the first continuous fiber reinforced thermoplastic sheet layer is 0.8 mm; The thickness of the second continuous fiber reinforced thermoplastic sheet layer is 1.6 mm; The thickness of the first polyamide hot melt adhesive film adhesive layer and the second polyamide hot melt adhesive film adhesive layer is 100 μm; The thickness of the third polyamide hot melt adhesive film bonding layer is 75 μm.

9. A bottom-protected battery pack, characterized in that: It includes a battery pack and a battery pack bottom guard plate arranged at the bottom of the battery pack; The battery pack bottom protective plate is selected from the battery pack bottom protective plate according to any one of claims 1-8.

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