Battery bottom protection plate

Abstract

The utility model relates to the field of new energy, and discloses a battery bottom protection plate which comprises an impact release layer, a first fiber reinforced resin layer, a metal layer, an impact absorption layer and a second fiber reinforced resin layer, and the first fiber reinforced resin layer, the metal layer and the second fiber reinforced resin layer are all arranged between the impact release layer and the impact absorption layer. And the impact release layer, the first fiber reinforced resin layer, the metal layer, the second fiber reinforced resin layer and the impact absorption layer are laminated. The battery bottom guard plate has the beneficial effects that the battery bottom guard plate adopts the design concept of gradient energy absorption and has high impact resistance, and meanwhile, the multi-layer composite structure can be produced in different processes, so that the heat dissipation between layers is reduced, the interface bonding force is improved, the reliability of the bottom guard plate is improved, the protection function of the bottom guard plate is ensured, and the service life of the bottom guard plate is prolonged. And the battery pack can be well protected.

Description

Technical Field

[0001] The utility model relates to the field of new energy, in particular to a battery bottom guard plate. Background Art

[0002] With the rapid development of the new energy vehicle market, the safety performance of new energy electric vehicles has become the focus of consumer attention. Among them, the underbody guard, as an important component of electric vehicles, its safety is directly related to the overall performance of the vehicle and the safety of passengers. The underbody guard of new energy electric vehicles is a protective device installed at the bottom of the electric vehicle. It is mainly used to protect key components such as battery packs and motors from impact and damage from external objects. The existence of the underbody guard not only improves the safety performance of electric vehicles, but also improves driving stability, waterproof and dustproof capabilities, etc. to a certain extent. At present, the material scheme of the underbody guard has gradually changed from the traditional metal plate + PVC anti-corrosion coating scheme to a product scheme that combines metal plates with higher impact resistance and composite materials. Among them, steel-plastic composite panels are a typical representative. Steel-plastic composite panels can prevent the underbody guard from being penetrated by external impact, but there is still a large amount of deformation. It cannot avoid the deformation of the liquid cooling plate and battery cells above the underbody guard, and there is still a large safety hazard. Therefore, there is an urgent need for a new type of battery underbody guard to solve the above problems. Utility Model Content

[0003] The purpose of this application is to provide a battery bottom guard plate to improve the impact resistance and reliability of the bottom guard plate.

[0004] The purpose of this application is achieved through the following technical solutions:

[0005] A battery bottom guard plate includes: an impact release layer, a first fiber-reinforced resin layer, a metal layer, an impact absorbing layer and a second fiber-reinforced resin layer, wherein the first fiber-reinforced resin layer, the metal layer and the second fiber-reinforced resin layer are all arranged between the impact release layer and the impact absorbing layer, and the impact release layer, the first fiber-reinforced resin layer, the metal layer, the second fiber-reinforced resin layer and the impact absorbing layer are stacked.

[0006] In some embodiments of the present application, the first fiber-reinforced resin layer and the second fiber-reinforced resin layer are respectively disposed on both sides of the metal layer.

[0007] In some embodiments of the present application, a first adhesive layer and a second adhesive layer are further included, wherein the first adhesive layer is arranged between the first fiber-reinforced resin layer and the metal layer, and the second adhesive layer is arranged between the metal layer and the second fiber-reinforced resin layer.

[0008] In some embodiments of the present application, the impact-releasing layer is located above the impact-absorbing layer, and the thickness of the impact-releasing layer is no greater than the thickness of the impact-absorbing layer.

[0009] In some embodiments of the present application, the thickness of the impact-releasing layer is 0.1 mm to 1 mm, and the thickness of the impact-absorbing layer is 0.2 mm to 2 mm.

[0010] In some embodiments of the present application, the first fiber-reinforced resin layer is located above the second fiber-reinforced resin layer, and the thickness of the first fiber-reinforced resin layer is not greater than the thickness of the second fiber-reinforced resin layer.

[0011] In some embodiments of the present application, the thickness of the first fiber-reinforced resin layer is 0.1 mm-1 mm, and the thickness of the second fiber-reinforced resin layer is 0.2 mm-2 mm.

[0012] In some embodiments of the present application, the impact release layer is located above the impact absorption layer, the first fiber-reinforced resin layer is located above the second fiber-reinforced resin layer, a third adhesive layer is provided between the impact release layer and the first fiber-reinforced resin layer, or they are bonded by surface treatment, and a fourth adhesive layer is provided between the impact absorption layer and the second fiber-reinforced resin layer, or they are bonded by surface treatment.

[0013] In some embodiments of the present application, the thickness of the first adhesive layer and the second adhesive layer are both 0.04 mm-0.2 mm.

[0014] In some embodiments of the present application, the impact-releasing layer and the impact-absorbing layer are both made of polyurea.

[0015] The battery bottom guard plate of the present application is based on a steel-plastic composite plate composed of a metal layer and a fiber-reinforced resin layer, and an impact release layer and an impact absorption layer are added. The impact absorption layer is arranged on the outside and can absorb part of the impact force. The impact force passing through the impact absorption layer reaches the metal layer and the fiber-reinforced resin layer and is further absorbed. The remaining impact force reaches the impact release layer and is released, thereby realizing the design concept of gradient energy absorption of the battery bottom guard plate, which has high impact resistance. At the same time, the multi-layer composite structure can be produced through separate processes to reduce heat dissipation between layers, improve interface adhesion, improve the reliability of the bottom guard plate, ensure the protective function of the bottom guard plate, and play a good protective role for the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural diagram of the battery bottom guard plate of the present application;

[0017] Figure 2 It is a structural diagram of Comparative Example 1 of the present application.

[0018] In the figure, 1, impact release layer; 2, first fiber reinforced resin layer; 3, metal layer; 4, impact absorbing layer; 5, second fiber reinforced resin layer; 6, first adhesive layer; 7, second adhesive layer; 8, honeycomb buffer layer. DETAILED DESCRIPTION

[0019] The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0020] In the description of this application, it should be understood that the terms "upper," "lower," "top," "bottom," "inner," and "outer" used herein to indicate orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of the present invention and simplify the description. They are not intended to indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0021] In this utility model, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, indirect connection through an intermediate medium, internal connection between two components, or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0022] like Figure 1 As shown, the first aspect of an embodiment of the present application proposes a battery bottom guard plate, comprising: an impact release layer 1, a first fiber reinforced resin layer 2, a metal layer 3, an impact absorbing layer 4 and a second fiber reinforced resin layer 5, the first fiber reinforced resin layer 2, the metal layer 3 and the second fiber reinforced resin layer 5 are all arranged between the impact release layer 1 and the impact absorbing layer 4, and the impact release layer 1, the first fiber reinforced resin layer 2, the metal layer 3, the second fiber reinforced resin layer 5 and the impact absorbing layer 4 are stacked.

[0023] Based on the above technical solution, the battery bottom guard plate of the present application, on the basis of a steel-plastic composite plate comprising a metal layer 3 and a fiber-reinforced resin layer, adds an impact release layer 1 and an impact absorption layer 4. The impact absorption layer 4 is arranged on the outside and can absorb part of the impact force. The impact force passing through the impact absorption layer 4 reaches the metal layer 3 and the fiber-reinforced resin layer and is further absorbed, and the remaining impact force reaches the impact release layer 1 and is released, thereby realizing the design concept of gradient energy absorption of the battery bottom guard plate, which has high impact resistance. At the same time, the multi-layer composite structure can be produced through separate processes to reduce heat dissipation between layers, improve interface adhesion, improve the reliability of the bottom guard plate, and ensure the protective function of the bottom guard plate.

[0024] The impact-releasing layer 1 and the impact-absorbing layer 4 are polymer materials with a density ranging from 0.9 g / cm³ to 2.0 g / cm³, a tensile strength ≥5 MPa, a tear strength ≥60 N / mm, and an elongation at break ≥50%. The impact layer can be in the form of a film, sheet, or liquid before lamination. The thickness of the film and sheet ranges from 0.05 mm to 5.0 mm, the solid content of the liquid is ≥70%, and the volatile content is <250 g / L. The pull-out force between the impact layer and the adjacent fiber-reinforced resin layer is ≥5 MPa. Optional materials include, but are not limited to, polyurethane, polyurea, ethylene propylene diene monomer (EPDM), random copolymers of ethylene and vinyl acetate (EVA), styrene-butadiene-styrene block copolymers (SEBS), and thermoplastic elastomers (POE) of random copolymers of ethylene and octene. The processing temperature range of the film and plate is 80℃~250℃, and the liquid impact layer can be adhered to the upper fiber reinforced resin layer and the lower fiber reinforced resin layer by a spraying process, with a viscosity of ≤1000mPa.s (25℃) and a gel time of ≤168h. In addition, the metal plate is a steel plate, and the outer surface of the steel plate is provided with a galvanized layer, a galvanized iron alloy layer or an electrophoretic paint protective layer. The impact release layer 1 and the impact absorption layer 4 constructed in the above manner can better reduce the impact force sent to the battery pack, thereby realizing the protective function of the bottom guard plate.

[0025] In some embodiments of the present application, Figure 1As shown, the first fiber-reinforced resin layer 2 and the second fiber-reinforced resin layer 5 are respectively disposed on either side of the metal layer 3. The first fiber-reinforced resin layer 2 and the second fiber-reinforced resin layer 5 are thermoplastic composite materials, composed of a fiber product and a thermoplastic resin, wherein the fiber content is 30% to 85% by weight. The fiber product is a combination of one or more of alkali-free glass fiber, medium-alkali glass fiber, high-alkali glass fiber, carbon fiber, aramid fiber, basalt fiber, and silicon carbide fiber; the fiber product is in the form of one or more of a fiber mat, a woven woven fabric (plain, twill, or satin), or a multiaxial fabric, with a fiber diameter of 5 to 20 μm. The thermoplastic resin is composed of 15% to 70% (by mass) polyolefin resin, 0 to 20% additives, and 0 to 10% filler. The selected resin matrix has a melt index range of 10 to 100 g / 10 min. The polyolefin resin is one or more of polyethylene, polypropylene, recycled polyethylene, and recycled polypropylene, in any ratio. The additives include one or more combinations of functional additives such as compatibilizers, antioxidants, lubricants, anti-drip agents, plasticizers, coupling agents, anti-aging agents, and flame retardants. The combination of the first fiber-reinforced resin layer 2 and the second fiber-reinforced resin layer 5 using the above components can better absorb impact force.

[0026] Specifically, such as Figure 1 As shown, the chassis further includes a first adhesive layer 6 and a second adhesive layer 7. The first adhesive layer 6 is disposed between the first fiber-reinforced resin layer 2 and the metal layer 3, and the second adhesive layer 7 is disposed between the metal layer 3 and the second fiber-reinforced resin layer 5. The first adhesive layer 6 and the second adhesive layer 7 are used to stably and firmly connect the metal layer 3 to the upper and lower fiber-reinforced resin layers, thereby improving the reliability of the chassis.

[0027] In some embodiments of the present application, Figure 1 As shown, the impact-releasing layer 1 is located above the impact-absorbing layer 4, and its thickness is no greater than that of the impact-absorbing layer 4. One side of the impact-releasing layer 1 is close to the internal structure of the battery pack, while one side of the impact-absorbing layer 4 is close to the outside. Since the impact-absorbing layer 4 directly faces the impact force, it requires a greater thickness to resist the impact. However, the impact-releasing layer 1 located on the innermost side can be thinner to take into account the lightweighting of the bottom guard plate.

[0028] Specifically, such as Figure 1 As shown, the thickness of the impact-releasing layer 1 is 0.1 mm to 1 mm, and the thickness of the impact-absorbing layer 4 is 0.2 mm to 2 mm. While the thickness of the impact-releasing layer 1 is no greater than that of the impact-absorbing layer 4, employing these thicknesses can better balance impact resistance and lightweighting. More preferably, the thickness of the impact-releasing layer 1 is 0.5 mm, and the thickness of the impact-absorbing layer 4 is 1 mm.

[0029] In some embodiments of the present application, Figure 1 As shown, the first fiber-reinforced resin layer 2 is located above the second fiber-reinforced resin layer 5, and the thickness of the first fiber-reinforced resin layer 2 is no greater than that of the second fiber-reinforced resin layer 5. Similar to the thickness settings of the impact-releasing layer 1 and the impact-absorbing layer 4, the first fiber-reinforced resin layer 2 is closer to the interior of the battery pack than the second fiber-reinforced resin layer 5. Therefore, the first fiber-reinforced resin layer 2 is thinner, achieving a better lightweight effect, while the second fiber-reinforced resin layer 5 is thicker, achieving better impact resistance.

[0030] Specifically, such as Figure 1 As shown, the thickness of the first fiber-reinforced resin layer 2 is 0.1 mm to 1 mm, and the thickness of the second fiber-reinforced resin layer 5 is 0.2 mm to 2 mm. While the thickness of the first fiber-reinforced resin layer 2 is no greater than that of the second fiber-reinforced resin layer 5, employing these thicknesses can better balance impact resistance and lightweighting. More preferably, the thickness of the first fiber-reinforced resin layer 2 is 0.6 mm, and the thickness of the second fiber-reinforced resin layer 5 is 1 mm.

[0031] In some embodiments of the present application, Figure 1 As shown, the impact-releasing layer 1 is positioned above the impact-absorbing layer 4, and the first fiber-reinforced resin layer 2 is positioned above the second fiber-reinforced resin layer 5. A third adhesive layer is provided between the impact-releasing layer 1 and the first fiber-reinforced resin layer 2, or the layers are bonded together through surface treatment. A fourth adhesive layer is provided between the impact-releasing layer 1 and the first fiber-reinforced resin layer 2, or the interfaces are treated with flame, sandblasting, plasma, or special reagents, thereby achieving a stable connection between the impact-releasing layer 1 and the first fiber-reinforced resin layer 2. A fourth adhesive layer is provided between the impact-absorbing layer 4 and the second fiber-reinforced resin layer 5, or the interfaces are treated with flame, sandblasting, plasma, or special reagents, thereby achieving a stable connection between the impact-releasing layer 1 and the first fiber-reinforced resin layer 2.

[0032] Specifically, such as Figure 1 As shown, the thickness of the first adhesive layer 6 and the second adhesive layer 7 are both 0.04 mm to 0.2 mm. More preferably, the thickness of the first adhesive layer 6 and the second adhesive layer 7 are both 0.1 mm, which can take into account both the bonding strength and the lightweight requirements.

[0033] In some embodiments of the present application, Figure 1As shown, the impact-releasing layer and the impact-absorbing layer are both made of polyurea. Polyurea is an elastomeric substance produced by the reaction of an isocyanate component and an amino compound component. It has properties such as corrosion resistance, water resistance, and wear resistance, and can effectively achieve the purpose of impact resistance.

[0034] A second aspect of the present application provides a battery pack comprising a battery body and the aforementioned battery bottom shield, disposed beneath the battery body. The battery bottom shield disposed beneath the battery body effectively prevents damage to the battery body from impact forces from below. Because the battery pack includes the aforementioned battery bottom shield, it possesses all the benefits of the aforementioned battery bottom shield, which will not be further elaborated here.

[0035] The preparation method of the bottom guard plate of the present application is described here, which includes the following steps:

[0036] 1. Composite of the first fiber-reinforced resin layer 2, the metal layer 3 and the second fiber-reinforced resin layer 5

[0037] 1. Preparation of fiber-reinforced resin layer: The fiber product is fully impregnated with a thermoplastic resin melt / solution, cooled and shaped, cut, and rolled to form a fiber-reinforced prepreg sheet. The fiber-reinforced resin layer is obtained by laying out multiple layers of fiber-reinforced prepreg sheets, performing high-temperature hot-pressing and laminating, and cooling and shaping.

[0038] 2. The first fiber-reinforced resin layer 2, the first adhesive layer 6, the metal layer 3, the second adhesive layer 7 and the second fiber-reinforced resin layer 5 are manually or automatically unwound and stacked together, and then subjected to high-temperature hot-pressing lamination, cooling and shaping, and fixed-length cutting to obtain a steel-plastic composite board;

[0039] 2. Surface treatment of the product in step 1

[0040] The steel-plastic composite panels are surface treated using continuous online treatment methods, including but not limited to flame treatment, sandblasting, plasma treatment, special reagent treatment, etc.

[0041] 3. Composite or Adhesion of the Impact-Releasing Layer 1 and the Impact-Absorbing Layer 4

[0042] If the buffer layer is a membrane or plate material, the upper and lower buffer layers are bonded to the surface-treated steel-plastic composite board by hot pressing; if the buffer layer is liquid, the impact layer is bonded to the steel-plastic composite board by spraying.

[0043] In order to specifically demonstrate the beneficial effects of the bottom guard plate of the present application, the following examples and comparative examples are provided:

[0044] Example 1:

[0045] like Figure 1As shown, the first fiber-reinforced resin layer 2 is continuous glass fiber reinforced polypropylene with a glass fiber content of 65% and a thickness of 0.6 mm. The second fiber-reinforced resin layer 5 is continuous glass fiber reinforced polypropylene with a glass fiber content of 65% and a thickness of 1.0 mm. The thickness of the first adhesive layer 6 and the second adhesive layer 7 is 0.1 mm. The metal plate is galvanized DP780 steel plate with a thickness of 0.8 mm. The impact absorbing layer 4 is made of slow-drying polyurea with a density of 1.1 g / cm 3 , tensile strength 8.0MPa, tear strength 70N / mm, elongation at break 350%, thickness 1.0mm. Recommended density 1.1g / cm 3 , tensile strength 8.0MPa, tear strength 70N / mm, elongation at break 350%, thickness 0.5mm. The viscosity of the upper and lower impact layers is 500mPa.s (25°C), and the gel time is 2h. Before spraying the upper and lower impact layers, the surface of the steel-plastic composite panel is treated with plasma.

[0046] The sample was subjected to a roller peel test and an impact test, and the impact energy of the material was evaluated based on a deformation of 6 mm.

[0047] Comparative Example 1:

[0048] like Figure 2 As shown, a protective plate with a buffer layer includes a first fiber reinforced resin layer 2, a first adhesive layer 6, a metal layer 3, a second adhesive layer 7, a honeycomb buffer layer 8 and a second fiber reinforced resin layer 5 stacked in sequence.

[0049] The upper fiber reinforcement layer is continuous glass fiber reinforced polypropylene (65% glass fiber content) and 1.0mm thick. The upper fiber reinforcement layer is continuous glass fiber reinforced polypropylene (65% glass fiber content) and 1.0mm thick. The thickness of the first and second resin bonding layers is 0.1mm. The metal plate is galvanized DP780 steel plate, 0.8mm thick. The honeycomb buffer layer is made of polypropylene, 7mm thick, and the honeycomb tube diameter is 8.0mm.

[0050] The sample was subjected to a roller peel test and an impact test. The roller peel test adopted the sandwich structure roller peel strength test method GB / T1457-2005, and the deformation of 6mm was used as the judgment to evaluate the impact energy of the material.

[0051] The specific test data comparison table is as follows:

[0052] Table 1 Data comparison table of Example 1 Comparative Example 1

[0053]

[0054] Impact layer test standards:

[0055] Solid content: GB / T 1725;

[0056] Density: GB / T6750;

[0057] Tensile strength: GB / T 5210

[0058] Impact resistance: GB / T 1732

[0059] Volatile matter content: GB / T 37884-2019

[0060] Tensile strength: GB / T 528

[0061] Tear strength: GB / T 529

[0062] Elongation at break: GB / T 528

[0063] Drop hammer impact: hammer head diameter d = 25 mm, base support area r = 30 mm (circular), 600 J impact energy, lower impact absorption layer, observe the deformation of the aluminum plate.

[0064] From the above data comparison table, it can be clearly seen that Example 1 can withstand greater impact energy and greater roller peel strength under the premise of smaller thickness, indicating that Example 1 can better achieve the bottom protection function of the battery pack compared with Comparative Example 1.

[0065] In summary, the battery bottom guard plate of the present application is based on a steel-plastic composite plate that adopts a metal layer 3 and a fiber-reinforced resin layer, and adds an impact release layer 1 and an impact absorption layer 4. The impact absorption layer 4 is arranged on the outside and can absorb part of the impact force. The impact force passing through the impact absorption layer 4 reaches the metal layer 3 and the fiber-reinforced resin layer and is further absorbed. The remaining impact force reaches the impact release layer 1 and is released, thereby realizing the design concept of gradient energy absorption of the battery bottom guard plate, with high impact resistance. At the same time, the multi-layer composite structure can be produced through separate processes, which reduces heat dissipation between layers, improves interface adhesion, improves the reliability of the bottom guard plate, ensures the protective function of the bottom guard plate, and can play a good protective role for the battery pack.

[0066] The above is only a preferred embodiment of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and replacements can be made without departing from the technical principles of the present application. These improvements and replacements should also be regarded as the scope of protection of the present application.

Claims

1. A battery bottom guard plate, characterized in that: include: An impact-releasing layer, a first fiber-reinforced resin layer, a metal layer, an impact-absorbing layer, and a second fiber-reinforced resin layer, wherein the first fiber-reinforced resin layer, the metal layer, and the second fiber-reinforced resin layer are all arranged between the impact-releasing layer and the impact-absorbing layer, and the impact-releasing layer, the first fiber-reinforced resin layer, the metal layer, the second fiber-reinforced resin layer, and the impact-absorbing layer are stacked.

2. The battery bottom guard plate according to claim 1, characterized in that: The first fiber-reinforced resin layer and the second fiber-reinforced resin layer are respectively disposed on both sides of the metal layer.

3. The battery bottom guard plate according to claim 2, characterized in that: The invention further comprises a first adhesive layer and a second adhesive layer, wherein the first adhesive layer is arranged between the first fiber-reinforced resin layer and the metal layer, and the second adhesive layer is arranged between the metal layer and the second fiber-reinforced resin layer.

4. The battery bottom guard plate according to claim 1, characterized in that: The impact-releasing layer is located above the impact-absorbing layer, and a thickness of the impact-releasing layer is no greater than a thickness of the impact-absorbing layer.

5. The battery bottom guard plate according to claim 4, characterized in that: The thickness of the impact-releasing layer is 0.1 mm to 1 mm, and the thickness of the impact-absorbing layer is 0.2 mm to 2 mm.

6. The battery bottom guard plate according to claim 2, characterized in that: The first fiber-reinforced resin layer is located above the second fiber-reinforced resin layer, and a thickness of the first fiber-reinforced resin layer is not greater than a thickness of the second fiber-reinforced resin layer.

7. The battery bottom guard plate according to claim 6, characterized in that: The thickness of the first fiber-reinforced resin layer is 0.1 mm to 1 mm, and the thickness of the second fiber-reinforced resin layer is 0.2 mm to 2 mm.

8. The battery bottom guard plate according to claim 2, characterized in that: The impact-releasing layer is located above the impact-absorbing layer, the first fiber-reinforced resin layer is located above the second fiber-reinforced resin layer, a third adhesive layer is provided between the impact-releasing layer and the first fiber-reinforced resin layer or they are bonded by surface treatment, and a fourth adhesive layer is provided between the impact-absorbing layer and the second fiber-reinforced resin layer or they are bonded by surface treatment.

9. The battery bottom guard plate according to claim 3, characterized in that: The thickness of the first adhesive layer and the second adhesive layer are both 0.04 mm to 0.2 mm.

10. The battery bottom guard plate according to claim 1, characterized in that: The impact-releasing layer and the impact-absorbing layer are both made of polyurea.

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