Energy-absorbing battery protection plate based on metal rubber filling and preparation method of energy-absorbing battery protection plate

Abstract

The invention relates to an energy-absorbing battery protection plate based on metal rubber filling and a preparation method thereof.The energy-absorbing battery protection plate comprises a first fiber-reinforced composite plate layer, a metal plate and a second fiber-reinforced composite plate layer which are sequentially arranged in the thickness direction, a plurality of through holes are vertically formed in the metal plate in a penetrating mode, and metal rubber columns are inserted into the through holes in an interference mode; according to the battery protection plate, the high-damping hysteretic energy absorption characteristic of metal rubber and the bearing diffusion capacity of the metal plate are fully utilized, the impact peak acceleration can be remarkably reduced on the premise that it is guaranteed that the mass per unit area is controlled, and the service life of the battery protection plate is prolonged. And meanwhile, the composite material has excellent electrical insulation and heat resistance, and is particularly suitable for the fields of bottom protection plates of battery packs of electric vehicles and the like.

Description

A metal-rubber filled energy-absorbing battery cover plate and its preparation method Technical Field

[0001] This invention relates to the field of composite material preparation technology, specifically to an energy-absorbing battery guard plate based on metal rubber filling and its preparation method. Background Technology

[0002] With the widespread adoption of electric vehicles, battery pack bottom protection plates need to meet multiple performance requirements under limited installation space and strict constraints on unit area mass, including resistance to stone impacts and falling objects, penetration resistance, vibration and noise reduction, heat resistance and electrical insulation, and weather and corrosion resistance. Vehicle operating conditions are characterized by multi-source random impacts and broadband vibrations, and long maintenance cycles place higher demands on the cyclic stability and damage tolerance of the protection plate structure. In existing technologies, common battery protection plate solutions include: 1. Single metal plate (steel or aluminum alloy): While convenient to form and assemble and with high load-bearing stiffness, it exhibits high peak acceleration, significant rebound, and poor noise control under impact. Furthermore, achieving penetration resistance often relies on increasing thickness, leading to increased overall weight and cost; 2. Traditional fiber-reinforced composite laminate structures: For example, the "GFRP / steel plate / GFRP" symmetrical laminate structure, while balancing stiffness and insulation to some extent, is prone to through-cracks or continuous tearing paths in the in-plane metal core layer under impact loads, and the interlayer bonding strength is limited. In contrast, the improvement in its specific energy absorption and cyclic energy dissipation stability (ΔW retention rate) is limited; therefore, there is an urgent need for a new type of protective plate structure that can synergistically leverage the high load-bearing capacity of metals and the energy absorption characteristics of damping materials to solve the above problems. Summary of the Invention

[0003] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is to provide an energy-absorbing battery guard plate based on metal rubber filling and its preparation method. The guard plate adopts a composite material laminate structure. This structure utilizes the high damping hysteresis energy absorption of metal rubber and the load-bearing diffusion capacity of metal plate to overcome the problem that existing guard plates are difficult to balance in terms of energy absorption and vibration reduction, impact resistance and interface reliability. Under the same unit area mass, it can significantly reduce the peak impact acceleration and improve the loss factor under broadband vibration, while meeting the requirements of structural stiffness, insulation and heat resistance.

[0004] To solve the above-mentioned technical problems, the technical solution of the present invention is: an energy-absorbing battery guard plate based on metal rubber filling and its preparation method, comprising a first fiber-reinforced composite plate layer, a metal plate and a second fiber-reinforced composite plate layer arranged sequentially along the thickness direction, wherein a plurality of through holes are vertically opened on the metal plate and metal rubber pillars are inserted into the through holes with interference fit, and the first fiber-reinforced composite plate layer, the metal plate and the second fiber-reinforced composite plate layer are glued and fixed together with adhesive.

[0005] Furthermore, the opening of the through hole is chamfered or rounded to facilitate the penetration of adhesive, which helps the resin form a flanged rivet at the opening and reduces stress concentration.

[0006] Furthermore, the through holes are at least one of round holes, oblong holes, or slits, and the through holes are arranged in an array on the metal plate. The center distance between adjacent through holes is 2–6 times the hole diameter, and the minimum distance from the through hole to the edge of the metal plate is not less than 2 times the hole diameter.

[0007] Furthermore, the metal rubber column has a diameter interference of 1-5% with respect to the through hole.

[0008] Furthermore, the metal plate is selected from one or more of steel, aluminum alloy, magnesium alloy, titanium alloy or copper alloy; the first fiber reinforced composite plate layer and the second fiber reinforced composite plate layer are selected from epoxy, vinyl ester, unsaturated polyester or phenolic resin-based composite materials.

[0009] Furthermore, the metal rubber column has a spatial network-like helical entanglement structure with a relative density of 0.18-0.5. After being filled into the through hole, the metal rubber column is in a radially pre-compressed state, and the radial constraint force of the hole wall is used to improve its dry friction damping energy dissipation efficiency. The wire material inside the metal rubber column is selected from one or more of stainless steel, nickel and their alloys, and the wire diameter is between 0.15-0.3 mm.

[0010] Furthermore, the height h of the metal-rubber column and the thickness t of the metal plate satisfy h=(1.05–1.20) t, preferably h=1.1t, so as to form axial pre-tightening and improve interfacial shear and peel strength during the lamination and curing process.

[0011] A method for preparing an energy-absorbing battery protective plate based on metal-rubber filling comprises the following steps: Step 1: Forming through holes in a metal plate, shaping and cleaning the hole openings; Step 2: Preparing metal-rubber pillars and filling them with an interference fit to the through holes; Step 3: Stacking a first fiber-reinforced composite board layer and a second fiber-reinforced composite board layer on the upper and lower sides of the metal plate respectively, and placing an adhesive between the layers, curing them through a hot-pressing process at a set temperature and pressure to achieve adhesive bonding between the layers; the adhesive forms through rivets in the holes and together with the metal-rubber pillars and the hole walls constitutes a three-dimensional locking key; Step 4: Trimming the edges of the cured plate and applying a sealing and protective coating.

[0012] Furthermore, the preparation method of the metal rubber column used to fill the through hole in step two includes the following steps: S1: Wire selection and pretreatment: Select stainless steel, nickel or its alloy metal wire, determine the wire diameter, and then degrease and dry it; S2: Spiral winding: Spiral wind the metal wire to form a coiled spring-like coil under a set pitch and winding diameter; S3: Stretching and unwinding: Apply axial stretching to the coiled spring-like coil to loosen and decouple it, obtaining a spatially entangled wire coil; S4: Blank shaping: Perform multi-directional kneading and light pressing on the wire coil to form a porous blank with a size approximately similar to the through hole specification; S5: Molding and densification: Place the blank in a limiting mold and press it into a columnar blank under pressure; S6: Post-treatment: Perform ultrasonic cleaning on the columnar blank and dry it in an electric heating blower dryer to obtain the finished metal rubber column.

[0013] Preferably, in step three, the hot-press curing process parameters are: curing temperature 80~150℃, pressure 0.3~0.8MPa, holding time 1 hour, and standing for 12 hours after curing.

[0014] Furthermore, after the edge trimming and sealing protective coating treatment of the board material in step four is completed, it enters the inspection process. After passing the inspection, the laminated composite board production is completed.

[0015] Compared with existing technologies, this invention has the following advantages: This invention employs a composite material laminate structure, which utilizes the high damping hysteresis energy absorption of metal rubber and the load-bearing diffusion capacity of the metal plate to overcome the difficulty of simultaneously achieving energy absorption and vibration reduction, impact resistance, and interface reliability in existing protective plates. Under the same unit area mass, it significantly reduces peak impact acceleration and improves the loss factor under broadband vibration, while simultaneously meeting structural stiffness, insulation, and heat resistance requirements. The manufacturing method is simple and easy to operate, requires no special or expensive equipment, is low-cost, and has significant value for industrial application.

[0016] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0017] Figure 1 is a structural schematic diagram of an embodiment of the present invention; Figure 2 is a three-dimensional perspective structural schematic diagram of an embodiment of the present invention; Figure 3 is a schematic diagram of the cooperation between the metal plate and the metal rubber column in an embodiment of the present invention; Figure 4 is a force principle diagram of an embodiment of the present invention under impact; Figure 5 is an impact test data curve of an embodiment of the present invention and a comparative example.

[0018] In the figure: 1-First fiber-reinforced composite board layer, 2-Metal plate, 3-Second fiber-reinforced composite board layer, 4-Metal rubber column, 5-Adhesive, 6-Through hole. Detailed Implementation

[0019] To enhance understanding of the present invention, it will be further described in detail below with reference to embodiments and accompanying drawings. These embodiments are for illustrative purposes only and do not constitute a limitation on the scope of protection of the present invention.

[0020] Traditional metal veneer structures, while strong, have limited energy absorption and vibration damping capabilities. When subjected to impact, they are prone to high peak acceleration and rebound, resulting in significant stress concentration and making it difficult to achieve effective energy dissipation.

[0021] To address the aforementioned shortcomings, this embodiment provides a laminated protective plate with perforated metal plates filled with metal rubber that combines energy absorption, vibration reduction, impact resistance, and interface reliability, as well as its preparation method. As shown in Figures 1-5, an energy-absorbing battery protective plate based on metal rubber filling includes, in sequence, a first glass fiber reinforced resin layer 1, a metal plate 2 with through holes 6, metal rubber pillars 4 filled in the through holes, and a second glass fiber reinforced resin layer 3; the height of the metal rubber pillars is greater than the thickness of the metal plate.

[0022] The specific material selection is as follows: the metal plate 2 is made of 304 stainless steel; the first and second fiber reinforced composite plate layers (1, 3) are made of epoxy resin glass fiber board (FR-4) (or epoxy, vinyl ester, unsaturated polyester or phenolic resin-based composite materials); the metal rubber column 4 is a porous body with entangled metal wires, the wire material is made of 304 stainless steel wire (or nickel and its alloys), the relative density is 0.35, and the wire diameter is preferably 0.15–0.30 mm.

[0023] In this embodiment of the invention, the preparation method of the battery guard plate includes the following steps: Step 1, processing of the metal plate: 304 stainless steel is selected and cut according to the design dimensions. Through holes are processed on the steel plate according to the preset hole layout parameters, burrs are removed and the hole openings are rounded or chamfered to reduce stress concentration. Finally, the steel plate is cleaned and dried with anhydrous ethanol or acetone to remove surface oil stains.

[0024] Step 2: Prepare the metal rubber column and form an interference fit with the through hole. The metal rubber column is a wound metal porous body with a 1-5% diameter interference between the metal rubber column and the through hole. The prepared metal rubber column is inserted into the through hole according to the design position. During assembly, the prepared metal rubber column is pressed into the through hole according to the design position. Structural adhesive can be applied thinly to the hole wall to assist in positioning. The specific preparation of the metal rubber column is as follows: S1, select 304 stainless steel wire with a wire diameter of 0.15 mm, and degrease and dry it by ultrasonication; S2, wind it into a coiled spring wire bundle on a winding machine with a pitch of 1.0-3.0 mm and a coil diameter of 0.8-1.5 mm; S3, in order to reduce the internal stress of the coiled spring wire bundle and form a spatial network, stretch the coiled spring axially to 1.3-2.0 mm of its original length. The metal rubber column is formed into a three-dimensional entangled filament on a winding machine; S4, the filament is kneaded in multiple directions and lightly pressed into a near-cylindrical blank. The blank is placed in a limiting circular hole mold that matches the target aperture and pressed for 10–60 s under a pressure of 100–300 MPa to obtain a columnar blank. The outer diameter of the blank is controlled to be 1%–5% larger than the aperture, and the column height satisfies h=(1.05–1.20) t (t is the thickness of the steel plate); S5, the metal rubber columnar blank is placed in an ultrasonic cleaner for three cleanings, and the cleaned product is placed in an electric heating blower dryer for drying to obtain the finished metal rubber column.

[0025] Step 3: Lay fiberglass reinforced resin layers on both sides of the metal plate, using epoxy resin fiberglass board (FR-4). Apply polyurethane structural adhesive to the contact surface between the epoxy resin fiberglass board (FR-4) and the steel plate, using a flat plate hot pressing process with process parameters set at 80–150 °C, 0.5 MPa, and 60 min. During this process, because the metal rubber columns are slightly higher than the metal plate, the pressure will generate a pre-tightening force, while the adhesive flows and fills the gaps, forming a stable three-dimensional connection.

[0026] Step 4: After curing, demold and trim the laminated protective board, and apply a sealing / protective coating to the outer surface to meet the requirements for weather resistance and insulation.

[0027] Referring to Figure 4 in the instruction manual, when subjected to impact, the metal plate provides rigid support to limit overall deformation; at the same time, the metal rubber column, which is tightly constrained by the hole wall, uses the microscopic misalignment and dry friction (hysteresis effect) of the internal spiral metal wire to convert the impact kinetic energy into heat energy dissipation, and the microscopic rivets formed by the adhesive prevent interlayer separation during the energy absorption process.

[0028] To verify the superiority of the protective plate structure described in this invention in terms of impact resistance and energy absorption and vibration reduction, a set of comparative tests were set up in this embodiment.

[0029] 1. Sample Preparation: Plates with the same planar dimensions (150 mm × 100 mm) were selected as test objects, and the specific groupings are as follows: Example (Structure of the Invention): Prepared using the method described in this invention. The panel is a 2.0 mm thick epoxy resin fiberglass board (FR-4), the core layer is a 2.0 mm thick 304 stainless steel perforated plate (hole diameter 25 mm), the holes are filled with metal rubber pillars with a relative density of 0.35, and a micro-riveting structure is formed by adhesive.

[0030] Comparative example (traditional metal plate): using solid 304 stainless steel plates of equal thickness (2.0 mm), representing traditional heavy-duty protection solutions.

[0031] 2. Test Method: Low-speed impact testing was conducted using a drop weight impact tester. Test Standard: Refer to ASTM D7136 standard. Operating Conditions: Impact energy set to 27 J, hemispherical punch with a diameter of 16 mm, and fixed on all four sides.

[0032] The test results are shown in Figure 5. Compared with Comparative Example 1 (solid steel plate), the peak impact force of the present invention (Example 1) was reduced by 63.25% while the areal density was reduced by approximately 26%. This indicates that the present invention utilizes a sandwich structure that combines soft and hard materials to effectively avoid the rigid impact effect of pure metal plates when subjected to impact, and significantly improves the buffer protection capability for objects behind it.

[0033] The perforated metal plate filled with metal rubber laminate structure prepared by the method of the present invention can effectively overcome the problem that existing protective plates are difficult to balance in terms of energy absorption and vibration reduction, impact resistance and interface reliability. In this way, it can significantly reduce the peak impact acceleration and improve the loss factor under broadband vibration with the same unit area mass, while meeting the requirements of structural stiffness, insulation and heat resistance.

[0034] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

[0035] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A metal-rubber filled energy-absorbing battery protective plate, characterized in that: It includes a first fiber-reinforced composite board layer, a metal plate and a second fiber-reinforced composite board layer arranged sequentially along the thickness direction. The metal plate has several through holes vertically formed and metal rubber pillars are inserted into the through holes with an interference fit. The first fiber-reinforced composite board layer, the metal plate and the second fiber-reinforced composite board layer are glued and fixed together with adhesive.

2. The energy-absorbing battery guard plate based on metal-rubber filling according to claim 1, characterized in that: The opening of the through hole is chamfered or rounded.

3. The energy-absorbing battery guard plate based on metal-rubber filling according to claim 2, characterized in that: The through holes are at least one of round holes, oblong holes, or slots. The through holes are arranged in an array on the metal plate. The center distance between adjacent through holes is 2 to 6 times the hole diameter. The minimum distance from the through hole to the edge of the metal plate is not less than 2 times the hole diameter.

4. The energy-absorbing battery guard plate based on metal-rubber filling according to claim 1, characterized in that: The metal rubber column has a diameter interference of 1-5% with the through hole.

5. The energy-absorbing battery guard plate based on metal-rubber filling according to claim 1, characterized in that: The metal plate is selected from one or more of steel, aluminum alloy, magnesium alloy, titanium alloy or copper alloy; the first fiber reinforced composite plate layer and the second fiber reinforced composite plate layer are selected from epoxy, vinyl ester, unsaturated polyester or phenolic resin-based composite materials.

6. The energy-absorbing battery guard plate based on metal-rubber filling according to claim 1, characterized in that: The metal rubber column has a spatial network-like helical entanglement structure with a relative density of 0.18-0.

5. After being filled into the through hole, the metal rubber column is in a radial pre-compression state, and the radial constraint force of the hole wall is used to improve its dry friction damping energy dissipation efficiency. The wire material in the metal rubber column is selected from one or more of stainless steel, nickel and their alloys, and the wire diameter is between 0.15-0.3 mm.

7. The energy-absorbing battery guard plate based on metal-rubber filling according to claim 1, characterized in that: The height h of the metal rubber column and the thickness t of the metal plate satisfy h = (1.05 – 1.20) t.

8. A method for preparing an energy-absorbing battery protective plate based on metal-rubber filling, characterized in that, The energy-absorbing battery cover plate based on metal rubber filling as described in any one of claims 1-7 is adopted and the following steps are performed: Step 1: Forming through holes in the metal plate, shaping and cleaning the hole openings; Step 2: Preparing metal rubber pillars and filling them with an interference fit to the through holes; Step 3: Stacking a first fiber-reinforced composite board layer and a second fiber-reinforced composite board layer on the upper and lower sides of the metal plate respectively, and setting adhesive between the layers, and curing them through a hot pressing process at a set temperature and pressure to achieve adhesive bonding between the layers; Step 4: Trimming the edges of the cured plate and applying a sealing and protective coating.

9. A method for preparing an energy-absorbing battery guard plate based on metal-rubber filling according to claim 8, characterized in that: The preparation method of the metal-rubber column used to fill the through hole in step two includes the following steps: S1: Wire selection and pretreatment: Select stainless steel, nickel or its alloy metal wire, determine the wire diameter, and then degrease and dry it; S2: Spiral winding: Spiral wind the metal wire to form a coiled spring-like coil under a set pitch and winding diameter; S3: Stretching and unwinding: Apply axial tension to the coiled spring-like coil to loosen and decouple it, and obtain a spatially entangled wire coil; S4: Blank shaping: The filament ball is kneaded and lightly pressed in multiple directions to form a porous blank with a size similar to that of a through hole; S5: Molding and densification: The blank is placed in a limiting mold and pressed into a columnar blank under pressure; S6: Post-processing: The columnar blank is ultrasonically cleaned and dried in an electric heating blower to obtain the finished metal rubber column.

10. A method for preparing an energy-absorbing battery guard plate based on metal-rubber filling according to claim 8, characterized in that: In step three, the process parameters for hot pressing curing are: curing temperature 80~150℃, pressure 0.3~0.8MPa, holding time 1 hour, and standing for 12 hours after curing.

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