Foamed metal plate, composite plate, method of manufacture and battery case

Abstract

The application relates to a foamed metal plate, a composite plate, a preparation method and a battery box, wherein the foamed metal plate comprises modified closed-cell foamed metal and a phase change material; the modified closed-cell foamed metal is provided with a plurality of closed cells and a plurality of semi-closed cells arranged on the surface of the modified closed-cell foamed metal; a plurality of holes are arranged on the cell walls of the closed cells and the semi-closed cells; the holes are used for connecting adjacent closed cells, adjacent semi-closed cells and adjacent closed cells and semi-closed cells; and the phase change material is filled in the closed cells, the semi-closed cells and the holes. The modified closed-cell foamed metal is used as a base material, the phase change material is filled in the connected closed cells and semi-closed cells in the modified closed-cell foamed metal, and the foamed metal plate has good energy absorption effect and heat conductivity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a foamed metal plate, a composite plate, a preparation method and a battery box. BACKGROUND

[0002] During the charging and discharging process of a power battery, heat is generated due to ohmic impedance, electrochemical impedance and diffusion impedance. In order to reduce the influence of these heat on the battery interface side reaction and avoid the problem of battery thermal runaway caused by excessive heat accumulation, the traditional technology is to integrate liquid cooling technology in the battery box. However, the cooling effect of the liquid cooling technology is not good under the high-energy battery large-rate charging and discharging working condition.

[0003] Based on the demand of the battery system of an electric vehicle for light weight and thermal management performance, foamed metal has the characteristics of structure and function, which provides a new way to reduce weight and improve impact energy absorption capacity. However, foamed metal has poor forming processing performance. It cannot be cast due to too low forming ability, it cannot be pressure processed due to layer-by-layer collapse of foamed holes, and it cannot be welded due to the disappearance of weld pores during welding.

[0004] Therefore, how to provide a plate with energy absorption and heat dissipation has become a technical problem that needs to be solved urgently at present. SUMMARY

[0005] Therefore, it is necessary to provide a foamed metal plate, a composite plate, a preparation method and a battery box, which use modified closed-cell foamed metal as a base material, fill phase change materials into the semi-closed cells, closed cells and holes that are interconnected in the modified closed-cell foamed metal, and have good energy absorption effect and thermal conductivity.

[0006] In a first aspect, the present application provides a foamed metal plate, which comprises modified closed-cell foamed metal and a phase change material.

[0007] The modified closed-cell foamed metal is provided with a plurality of closed cells and a plurality of semi-closed cells on the surface of the modified closed-cell foamed metal. A plurality of holes are arranged on the cell walls of the closed cells and the semi-closed cells. The holes are used to connect adjacent closed cells, adjacent semi-closed cells and adjacent closed cells and semi-closed cells.

[0008] The phase change material is filled in the closed cells, the semi-closed cells and the holes.

[0009] In some embodiments, the holes include at least one of a hole structure and a crack structure. Optionally, the equivalent diameter of the holes is 0.05mm-1.20mm.

[0010] In some embodiments, the phase change material comprises at least one of crystalline hydrated salt, fatty acid, polyol and paraffin.

[0011] In some embodiments, the material of the modified closed-cell foam metal comprises at least one of aluminum, aluminum alloy, copper, copper alloy, nickel and nickel alloy.

[0012] In a second aspect, the present application provides a method for preparing the foam metal plate as described in the first aspect, the method comprising:

[0013] modifying the closed-cell foam metal to form pores in the inner walls of the closed cells and the half-closed cells, the pores connecting adjacent closed cells, adjacent half-closed cells, and adjacent half-closed cells and closed cells, to obtain a modified closed-cell foam metal;

[0014] filling the phase change material into the closed cells, the half-closed cells and the pores.

[0015] In some embodiments, the porosity of the closed-cell foam metal is 70% to 90%.

[0016] In some embodiments, the equivalent diameter of the half-closed cells is 1.0 mm to 5.0 mm.

[0017] In some embodiments, the equivalent diameter of the closed cells is 1.0 mm to 5.0 mm.

[0018] In some embodiments, the modification comprises at least one of sandblasting, fracturing and etching.

[0019] In some embodiments, the method for filling the phase change material comprises at least one of dipping and casting. Optionally, the dipping comprises vacuum dipping.

[0020] In some embodiments, after the phase change material is filled into the modified closed-cell foam metal, surface cleaning is performed to remove the phase change material on the surface of the modified closed-cell foam metal.

[0021] In a third aspect, the present application provides a composite plate, comprising the foam metal plate as described in the first aspect, and a fixing plate arranged on opposite sides of the foam metal plate.

[0022] An inorganic adhesive layer is arranged between the fixing plate and the foam metal plate.

[0023] In some embodiments, the fixing plate is provided with a mechanical connecting structure for fixedly connecting the foam metal plate. Optionally, the mechanical connecting structure comprises a surrounding plate provided at the edge of the fixing plate.

[0024] In some embodiments, the fixing plate is provided with a reinforced connecting layer on the side surface close to the inorganic adhesive layer; optionally, the surface of the reinforced connecting layer is in a rough surface structure.

[0025] In some embodiments, the material of the inorganic adhesive layer comprises at least one of phosphate adhesive, silicate adhesive, sulfate adhesive and borate adhesive.

[0026] In a fourth aspect, the present application provides a preparation method of the composite board according to the third aspect, wherein the preparation method of the composite board comprises:

[0027] The fixing plate and the foam metal plate are connected by the inorganic adhesive to obtain the composite board.

[0028] In some embodiments, the side surface of the fixing plate and the foam metal plate to be bonded is subjected to surface treatment before the fixing plate and the foam metal plate are connected.

[0029] Optionally, the surface treatment comprises: using phosphoric acid to scrub the surface of the fixing plate to form a phosphate film with a rough surface on the surface of the fixing plate.

[0030] In a fifth aspect, the present application provides a battery box comprising the composite board according to the third aspect.

[0031] Compared with the prior art, the present application has the following beneficial effects:

[0032] The present application uses modified closed-cell foam metal as a substrate, and the closed cells and semi-closed cells in the modified closed-cell foam metal are connected to each other through holes, which not only facilitates the filling of phase change materials, but also increases the filling amount of the phase change materials. Therefore, the present application not only maintains the structural strength of the closed-cell foam metal, but also ensures the uniform filling of the phase change materials, and has the characteristics of high strength and high heat dissipation. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 A cross-sectional schematic view of the foam metal plate provided in an embodiment of the present application;

[0034] Figure 2 A physical diagram of the modified foam metal provided in an embodiment of the present application;

[0035] Figure 3 A physical diagram of the foam metal plate provided in an embodiment of the present application;

[0036] Figure 4 A structural schematic diagram of a composite board provided in an embodiment of the present application;

[0037] Figure 5 A physical diagram of a composite board provided in an embodiment of the present application;

[0038] Figure 6 A structural schematic diagram of a battery box provided in an embodiment of the present application;

[0039] Figure 7 A compression performance diagram of a closed-cell foam aluminum after a channel modification treatment provided in Example 1 of the present application;

[0040] Figure 8 A compression performance diagram of a foam metal plate provided in Example 1 of the present application.

[0041] Wherein, 110-foam metal plate; 111-modified closed-cell foam metal; 112-phase change material; 120-fixing plate; 130-inorganic adhesive layer; 200-battery box; 100-composite board. DETAILED DESCRIPTION

[0042] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The preferred embodiments of the present application are shown in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0044] In the conventional technology, a liquid cooling device is integrated in a battery box, but the cooling effect is not good under high-energy battery large-rate charging and discharging conditions. Foam metal has the characteristics of structure and function, providing a new way to reduce weight and improve impact energy absorption. However, the processing performance of foam metal is poor, and it cannot be processed by pressure and the weld pores disappear during welding, resulting in welding processing. Although organic glue can be used to composite foam metal and metal plate, the high-temperature resistance and corrosion resistance are low. The present application modifies the closed-cell foam metal and fills the phase change material, which has excellent heat dissipation effect and structural strength, and then composites with the fixing plate using inorganic adhesive, which has high stability.

[0045] The first aspect of the present application provides a foam metal plate, such as Figure 1 As shown, the foam metal plate 110 includes a modified closed-cell foam metal 111 and a phase change material 112;

[0046] like Figure 2 As shown, the modified closed-cell metal foam 111 is provided with a plurality of closed cells, and a plurality of semi-closed cells are provided on the surface of the modified closed-cell metal foam. The cell walls of the closed cells and the cell walls of the semi-closed cells are both provided with a plurality of holes, and the holes are used to connect adjacent closed cells, adjacent semi-closed cells, and adjacent closed cells and semi-closed cells;

[0047] like Figure 3 As shown, the phase change material 112 is filled in the closed cells, the semi-closed cells and the holes.

[0048] This application is based on modified closed-cell metal foam. The modified closed-cell metal foam has excellent structural strength compared to open-cell metal foam. Through modification, the relatively independent closed cells and semi-closed cells in the modified closed-cell metal foam are connected, so that while ensuring the structural strength of the metal foam, more phase change materials can be filled, thereby improving the compressive strength and elastic modulus of the modified closed-cell metal foam, and having characteristics such as high heat dissipation.

[0049] The foam metal material used in this application has the advantage of being lightweight compared to conventional plates, which can reduce the weight of the plates. Moreover, the foam metal plates of this application can effectively resist external mechanical damage and absorb a large amount of energy when subjected to impact, thus playing a protective role.

[0050] It should be noted that foam metal refers to a metal material with a porous structure. Closed-cell foam metal refers to a metal material in which the closed cells in the foam metal are relatively closed and not connected to each other, wherein the closed cells refer to the independent bubble structure located inside the foam metal. In addition, there are semi-closed cells on the surface of the foam metal, and semi-closed cells refer to cells that are partially exposed to the surface. Furthermore, the holes in this application can be a pore structure or a crack structure, which can connect two adjacent semi-closed cells, two adjacent closed cells, and adjacent closed cells and semi-closed cells to achieve filling and circulation of phase change material.

[0051] In some embodiments, the closed-cell metal foam can be prepared by a liquid metal method or a powder metal method. Optionally, the liquid metal method includes a melt foaming method or a direct air blowing method; and the powder metal method includes a powder metallurgy method.

[0052] In some embodiments, the holes include at least one of a pore structure and a crack structure. Optionally, the holes have an equivalent diameter of 0.05mm to 1.20mm, such as 0.05mm, 0.10mm, 0.20mm, 0.30mm, 0.40mm, 0.50mm, 0.60mm, 0.70mm, 0.80mm, 0.90mm, 1.00mm, 1.10mm or 1.20mm.

[0053] The size of the holes is controlled in the present application to enable the phase change material to be filled into each closed cell and hole without affecting the structural strength of the closed-cell metal foam. The smaller the equivalent diameter of the holes, the better the energy absorption characteristics of the material can be guaranteed under the premise of enabling the phase change material to be filled. If the diameter of the connected holes is relatively large, there are problems of structural strength degradation and poor energy absorption capacity.

[0054] It should be noted that the shape of the holes is not specifically required or specially limited in the present application, and different shapes of holes can be formed according to different pore modification methods. For example, the holes can be connected pores, or can be connected cracks, i.e. the form of the holes can be straight holes, curved holes or crack channels, and the cross-sectional shape of the connected holes can be circular, regular polygonal or irregular polygonal.

[0055] In some embodiments, the phase change material includes at least one of a crystalline hydrated salt, a fatty acid, a polyol and a paraffin. Preferably, the phase change material includes paraffin, and the melting point of the paraffin is 30℃ to 60℃.

[0056] In some embodiments, the material of the modified closed-cell metal foam includes at least one of aluminum, aluminum alloy, copper, copper alloy, nickel and nickel alloy, i.e. it can be an aluminum alloy, a copper alloy, a nickel alloy, a copper-aluminum alloy, a copper-nickel alloy or an aluminum-nickel alloy. Preferably, the modified closed-cell metal foam includes a closed-cell aluminum foam. The aluminum foam has the advantage of low density, thereby reducing the weight of the product during use.

[0057] The second aspect of the present application provides a method for preparing the foam metal plate of the first aspect, and the method includes:

[0058] The closed-cell metal foam is modified to form holes in the inner walls of the closed cells and the semi-closed cells in the closed-cell metal foam, and the holes are connected to adjacent closed cells, adjacent semi-closed cells and adjacent semi-closed cells and closed cells, thereby obtaining a modified closed-cell metal foam;

[0059] The phase change material is filled into the closed cells, the semi-closed cells and the holes.

[0060] In some embodiments, the porosity of the closed-cell foam metal is 70% to 90%, for example, 70%, 72%, 74%, 76%, 78%, 80%, 82%, 84%, 86%, 88%, or 90%.

[0061] The present application controls the porosity of the closed-cell foam metal, so that the modified closed-cell foam metal has suitable structural strength and filling space of the phase change material, and has the advantages of balanced energy absorption capacity and lightweight. If the porosity is relatively high, the energy absorption strength may be insufficient; if the porosity is relatively low, the weight may not meet the requirement of lightweight.

[0062] In some embodiments, the equivalent diameter of the semi-closed cell is 1.0 mm to 5.0 mm, for example, 1.0 mm, 1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm, 3.5 mm, 4.0 mm, 4.5 mm, or 5.0 mm.

[0063] In some embodiments, the equivalent diameter of the closed cell is 1.0 mm to 5.0 mm, for example, 1.0 mm, 1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm, 3.5 mm, 4.0 mm, 4.5 mm, or 5.0 mm.

[0064] In some embodiments, the modification treatment includes at least one of sandblasting, fracturing, and etching. Optionally, the etching can be chemical etching.

[0065] The present application processes the inner wall of the closed cell and semi-closed cell of the closed-cell foam metal through channel modification treatment, forms connected pores or cracks, and facilitates uniform distribution and filling of the phase change material in the foam metal.

[0066] Exemplarily, a method for channel modification treatment is provided, including:

[0067] The closed-cell foam aluminum is subjected to channel modification by sandblasting, that is, sand is sprayed into the foam aluminum at a certain speed, the sand penetrates the bubble wall of the closed cell of the foam aluminum, and a modified closed-cell foam metal is obtained.

[0068] In some embodiments, the method for filling the phase change material includes at least one of dipping and pouring. Optionally, the dipping includes vacuum dipping.

[0069] Exemplarily, a method for filling the phase change material is provided, including:

[0070] The closed-cell foam metal and the phase change material after the modification of the pore are placed in a container, the container is vacuumized, the pressure in the container is 40Pa-50Pa, then the container is heated, the phase change material is heated and dissolved, the closed-cell foam metal is immersed for 0.5h-1.5h, then the vacuumization is stopped and the cooling is performed for 1h-2h.

[0071] In some embodiments, the phase change material filled into the modified closed-cell foam metal is surface cleaned, the phase change material on the surface of the modified closed-cell foam metal is removed, and the excess phase change material on the surface of the modified closed-cell foam metal is removed. For example, the method for removing the surface phase change material can be:

[0072] The modified closed-cell foam metal filled with the phase change material is cleaned by using a solvent to remove the phase change material on the surface of the modified closed-cell foam metal. Alternatively, the solvent has strong dissolving and removing ability to the phase change material, for example, the solvent can be aromatic hydrocarbon, long-chain alkane, and propylene oxide (PO) blocked fatty acid methyl ester ethoxylate and its sulfonate, wherein the aromatic hydrocarbon can be benzene, toluene or xylene; or, the excess phase change material on the surface of the modified closed-cell foam metal is directly cut off, cut away or wiped off by using a mechanical method.

[0073] The third aspect of the present application provides a composite board, as shown in Figure 4 and Figure 5 The composite board 100 comprises the foam metal plate 110 according to the first aspect, and the fixing plates 120 arranged on opposite sides of the foam metal plate 110.

[0074] An inorganic adhesive layer 130 is arranged between the fixing plates 120 and the foam metal plate 110.

[0075] In the present application, the inorganic adhesive is used to composite the foam metal plate and the fixing plate, which has stability at high and low temperatures, and the aging resistance is far better than that of the organic adhesive. Moreover, the method of riveting or welding in the traditional technology is avoided, and the present application has the characteristics of simple process, convenient use, high adhesive strength, good stability and the like. In addition, the composite board of the present application is water-resistant, oil-resistant and low in cost, the stress distribution at the connection is uniform, the linear expansion coefficient is small, the effect of the adhesive strength is 3-4 times that of the organic adhesive.

[0076] In some embodiments, the fixing plate comprises at least one of an aluminum plate, an aluminum alloy plate, a magnesium alloy plate, a steel plate and a fiber-reinforced plastic plate.

[0077] In some embodiments, the fixing plate is provided with a mechanical connection structure for fixedly connecting the foam metal plate.

[0078] The mechanical connecting mechanism is arranged to assist in connecting and fixing the fixed plate and the foam metal plate, which can realize the composite positioning of the fixed plate and the foam metal plate and strengthen the bonding effect of the inorganic adhesive.

[0079] It should be noted that the mechanical connecting structure in the present application refers to that the fixed plate and the foam metal plate can be connected only by the arranged mechanical connecting structure, for example, the fixed plate can be provided with a groove structure embedded with the foam metal plate, or a sleeve connecting piece is arranged to connect the fixed plate and the foam metal plate.

[0080] Optionally, the mechanical connecting structure comprises a surrounding plate arranged at the edge of the fixed plate. Further optionally, the height of the surrounding plate is half of the thickness of the foam metal plate. The surrounding plate structure is arranged at the edge of the fixed plate, and the groove structure is formed by the surrounding plate. During the composite process of the fixed plate and the foam metal plate, the foam metal plate is positioned and fixed by the surrounding plate, and a sleeve connecting piece structure can be further arranged on the fixed plate, so as to improve the composite stability of the fixed plate and the foam metal plate.

[0081] In some embodiments, a reinforcing connection layer is arranged on one side surface of the fixed plate. Optionally, the surface of the reinforcing connection layer is a rough surface structure.

[0082] The reinforcing connection layer is arranged on one side surface of the fixed plate, and can form a chemical bond with the inorganic adhesive layer, so as to effectively improve the bonding effect. Further, the one side of the fixed plate connected with the inorganic adhesive is arranged as a rough surface, and the surface of the foam metal plate is also a rough surface structure, so as to improve the bonding area and enhance the adhesion between the adhesive and the plate. The uneven parts on the rough surface can strengthen the "key", so that the adjacent parts on the surface are clamped, and the bonding strength is increased.

[0083] It should be noted that the rough surface refers to a structure with unevenness and certain roughness formed on the surface of the fixed plate, so as to improve the adhesive strength. For example, the rough surface can be formed by mechanical processing or chemical etching.

[0084] Further optionally, the material of the inorganic adhesive layer comprises at least one of a phosphate adhesive, a silicate adhesive, a sulfate adhesive and a borate adhesive. The phosphate adhesive is a kind of adhesive with concentrated phosphoric acid as a base material, which comprises at least one of a silicate-phosphate adhesive, an acid phosphate adhesive and an oxide-phosphate adhesive. For example, the inorganic adhesive can be a phosphoric acid-copper oxide adhesive, which is a high-strength, high-temperature-resistant chemical reaction type inorganic structure adhesive composed of phosphoric acid, copper oxide and aluminum oxide.

[0085] In the present application, the inorganic adhesive is used, and chemical bonding and physical bonding can be realized in the bonding process, and the two bonding methods effectively improve the bonding strength between the foam metal plate and the fixing plate.

[0086] In some embodiments, the thickness of the fixing plate is 1.0 mm to 5.0 mm, for example, 1.0 mm, 1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm, 3.5 mm, 4.0 mm, 4.5 mm or 5.0 mm.

[0087] In some embodiments, the thickness of the foam metal plate is 3 mm to 20 mm, for example, 3 mm, 4 mm, 6 mm, 8 mm, 10 mm, 12 mm, 14 mm, 16 mm, 18 mm or 20 mm.

[0088] In some embodiments, the thickness of the inorganic adhesive layer is 0.05 mm to 2.00 mm, for example, 0.05 mm, 0.10 mm, 0.20 mm, 0.40 mm, 0.60 mm, 0.80 mm, 1.00 mm, 1.20 mm, 1.40 mm, 1.60 mm, 1.80 mm or 2.00 mm.

[0089] The fourth aspect of the present application provides a preparation method of the composite plate as described in the third aspect, and the preparation method of the composite plate comprises:

[0090] The fixing plate and the foam metal plate are connected by using the inorganic adhesive to prepare the composite plate.

[0091] It should be noted that the foam metal plate is pretreated before being connected, and the phase change material on the surface of the foam metal plate is removed. For example, the pretreatment can be solvent cleaning, and the phase change material on the surface of the foam metal plate is removed by using a solvent to dissolve.

[0092] In some embodiments, before the fixing plate and the foam metal plate are connected, the surface of the fixing plate and the foam metal plate on the side to be bonded is subjected to surface treatment.

[0093] In the present application, the surface treatment is used to form a bonding strengthening surface on the side of the fixing plate connected with the inorganic adhesive, and the surface treatment can modify the material properties of the surface of the fixing plate or modify the structural features of the surface of the fixing plate.

[0094] Optionally, the surface treatment method comprises: using phosphoric acid to scrub the surface of the fixing plate to form a phosphate film with a rough surface on the surface of the fixing plate. It should be noted that the phosphate film with a rough surface means that after the surface of the fixing plate is scrubbed and corroded by using phosphoric acid, not only a rough surface with concave-convex is formed on the surface of the fixing plate, but also a phosphate film is formed on the surface layer of the fixing plate.

[0095] In the present application, the surface of the fixing plate is scrubbed with phosphoric acid, and the surface of the fixing plate is corroded by the acidity of the phosphoric acid. In the process of corrosion, a rough concave-convex structure is formed on the surface of the fixing plate, and a phosphate film is also formed on the surface of the fixing plate. The phosphate film has a good adhesive effect with the inorganic adhesive.

[0096] Taking the phosphoric acid-copper oxide adhesive for bonding the foam aluminum and the aluminum plate as an example, the phosphoric acid component and the copper oxide component in the phosphoric acid-copper oxide adhesive react to generate Cu 2+ The ion substitution reaction occurs on the surface of the aluminum material, that is, the metal surface is partially dissolved, and copper deposition is generated, thereby improving the close bonding of the adhesive with the surface of the aluminum material. Moreover, as the adhesive gradually solidifies, the viscosity continuously increases, thereby realizing chemical bonding. The adhesive plays a bonding role by using the adsorption force between the surface molecules of the adhesive. Moreover, a large number of bubbles are generated in the reaction, and the volume of the adhesive slightly expands, thereby playing a solidification role on the fixing plate, for example, playing an expansion fixation role on the fixing plate with a surrounding plate structure, thereby realizing the effect of physical bonding. The fixing plate with a rough surface has a larger bonding area in the bonding process, thereby improving the bonding effect. Moreover, the solidified adhesive structure formed by the uneven surface after solidification is clamped by the adjacent surfaces, thereby effectively improving the bonding effect and realizing mechanical bonding. Therefore, in the present application, the foam metal plate is combined with the fixing plate under the action of the inorganic adhesive, and the physical, chemical and mechanical effects are synergistically improved to improve the composite effect.

[0097] Exemplarily, a preparation method of the composite plate is provided, and the preparation method comprises the following steps:

[0098] The foam metal plate is cleaned with a solvent to remove the phase change material on the surface of the foam metal plate;

[0099] The side of the fixing plate, on which the inorganic adhesive layer is arranged, is scrubbed with phosphoric acid to form a rough surface and a phosphate film;

[0100] The inorganic adhesive is coated on the surface of the fixing plate with the phosphate film, and the fixing plate is preheated. The preheating temperature is 10-15℃ higher than the operating temperature of the inorganic adhesive.

[0101] The fixing plate coated with the inorganic adhesive after preheating is combined with the foam metal plate, and the composite plate is prepared after cooling to room temperature.

[0102] The fifth aspect of the present application provides a battery box, which comprises the composite plate according to the third aspect.

[0103] In one embodiment, as Figure 6As shown, the battery box 200 includes a bottom plate, two oppositely arranged side plates, two oppositely arranged end plates, and a cross beam connecting the two side plates, and the bottom plate, the two end plates and the two side plates are combined to form the battery box. Among them, the composite board 100 as the bottom plate of the battery box can effectively resist mechanical damage from the outside world and absorb a large amount of energy when impacted. When the power battery system is impacted by external force, the box will deform under the action of impact force. Compared with the traditional battery box, after filling the composite board of the application at the bottom of the box, it can absorb more impact energy under the condition that the external force remains unchanged, and play a protective role in the collision impact.

[0104] In some embodiments, the battery box is provided with a liquid cooling device located above the bottom plate.

[0105] The composite board in the application has the functions of light weight, energy absorption and thermal management, and is further coupled with the active liquid cooling for the thermal management system of the battery system, effectively solving the problem of large rate charge and discharge temperature rise. Moreover, the active cooling "integrated liquid cooling" and the passive cooling "foamed metal plate" are used in the structural design, and the battery system has good heat dissipation effect. After the battery cells in the battery system generate heat during charging and discharging, the battery first transfers the heat to the liquid cooling plate in the form of heat conduction. While the liquid cooling reduces the temperature, the phase change material can absorb part of the heat, reduce the cooling power of the battery system, and reduce the energy consumption. At the same time, when the battery system needs to be heated, the heat stored in the phase change material can also contribute to the battery system.

[0106] Embodiment 1

[0107] (1) Foamed metal plate

[0108] The closed-cell foamed aluminum plate prepared by the melt foaming method has a porosity of 84.5%, a thickness of 14 mm, a length of 700 mm, and a width of 300 mm;

[0109] The closed-cell foamed aluminum plate is subjected to channel modification treatment by physical modification method. Specifically, 30 mesh sand is used for sandblasting modification. After treatment, the semi-closed cell equivalent of the closed-cell foamed aluminum and the equivalent diameter of the closed cell are 2.0 mm to 4.0 mm, the holes include cracks and connected holes, and the equivalent diameter of the holes is 0.5 mm to 0.8 mm. Three modified closed-cell foamed aluminum plates prepared in the above manner are subjected to compression performance test, and the numbers are 1#, 2# and 3# respectively. The test results are shown in Figure 7

[0110] ​The modified closed-cell aluminum foam is placed in a container filled with paraffin wax having a melting point of 54°C, the container is sealed and vacuumized to below 45 Pa, the container is heated at 80°C to melt the paraffin wax and fill the closed-cell aluminum foam, the vacuumization is stopped after 60 min of continuous heating, and the container is cooled with cold water for 100 min;

[0111] After cooling, the excess phase change material on the surface of the foam metal plate is removed by mechanical cutting to obtain the foam metal plate (i.e. the closed-cell aluminum foam plate filled with phase change material), three foam metal plates obtained are numbered as 4#, 5# and 6# for compression performance test, and the test results are shown in Figure 8

[0112] (2) Composite plate

[0113] The foam metal plate is immersed in toluene for 30 s to further remove the paraffin wax on the surface of the foam metal plate;

[0114] The fixed plate is made of 6061 aluminum profile having a length of 700.4 mm, a width of 300.4 mm and a thickness of 3 mm, and the edge of the aluminum profile is provided with a surrounding plate having a height of 7.2 mm;

[0115] The surface of the aluminum profile with the surrounding plate is scrubbed with phosphoric acid to form a phosphoric acid aluminum film having a rough structure on the surface of the aluminum profile;

[0116] The phosphoric acid-copper oxide adhesive is coated on the side of the aluminum profile having a rough surface, and the aluminum profile is heated at a temperature of 12°C higher than the operating temperature of the phosphoric acid-copper oxide adhesive (82°C);

[0117] The aluminum profile coated with the phosphoric acid-copper oxide adhesive is adhered to both sides of the foam metal plate, and the composite plate is obtained after cooling after pressing.

[0118] Example 2

[0119] The foam metal plate and the composite plate are prepared according to the method of Example 1, except that the porosity of the closed-cell aluminum foam is 88.9%, and the equivalent diameter of the pores is 0.05 mm to 0.50 mm.

[0120] Example 3

[0121] The foam metal plate and the composite plate are prepared according to the method of Example 1, except that the porosity of the closed-cell aluminum foam is 74.1%, and the equivalent diameter of the pores is 0.50 mm to 1.20 mm.

[0122] Example 4 ​

[0123] A foamed metal plate and a composite plate were prepared according to the method of Example 1, with the difference being that the porosity of the closed-cell foamed metal was 92.6%.

[0124] Example 5

[0125] A foamed metal plate and a composite plate were prepared according to the method of Example 1, with the difference being that the porosity of the closed-cell foamed metal was 65%.

[0126] Example 6

[0127] A foamed metal plate and a composite plate were prepared according to the method of Example 1, with the difference being that the equivalent diameter of the pores was 0.02 mm.

[0128] Example 7

[0129] A foamed metal plate and a composite plate were prepared according to the method of Example 1, with the difference being that the equivalent diameter of the pores was 1.40 mm.

[0130] Example 8

[0131] A foamed metal plate and a composite plate were prepared according to the method of Example 1, with the difference being that the surface of the aluminum profile was not phosphoric acid scrubbed, and the inorganic adhesive was directly coated.

[0132] Comparative Example 1

[0133] A foamed metal plate and a composite plate were prepared according to the method of Example 1, with the difference being that the closed-cell foamed aluminum was replaced by an open-cell foamed aluminum with the same porosity, and the equivalent diameter of the pores was 3 mm to 3.5 mm.

[0134] Comparative Example 2

[0135] A foamed metal plate and a composite plate were prepared according to the method of Example 1, with the difference being that the closed-cell foamed aluminum was not subjected to a pore modification treatment, i.e., the closed-cell foamed aluminum did not have the pores with the communication function.

[0136] Comparative Example 3

[0137] A foamed metal plate and a composite plate were prepared according to the method of Example 1, with the difference being that the foamed metal plate was not filled with paraffin.

[0138] Comparative Example 4

[0139] A foamed metal plate and a composite plate were prepared according to the method of Example 1, with the difference being that the inorganic adhesive in the composite plate was replaced by an organic adhesive epoxy resin.

[0140] The modified closed-cell aluminum foam sheets and metal foam sheets prepared in the above examples and comparative examples were subjected to compression performance tests, and the composite sheets were subjected to adhesion and heat absorption performance tests. The test methods include:

[0141] Compression performance test: The compression test is a test to determine the mechanical properties of materials under axial static pressure. The equipment is an MTS E45 testing machine. The lower platen is fixed and the upper platen is loaded at a speed of 1 mm / min until the material is compacted. The compressive strength, elastic modulus, and energy absorption at 0.5 strain are obtained according to the stress-strain curve to characterize the energy absorption characteristics of the modified closed-cell aluminum foam plate and the foam metal plate. The test results are shown in Table 1.

[0142] Verification of bonding effectiveness: This can be verified through a three-point bending test. This involves placing a cross-section specimen on a bending device, adjusting the span, and applying load until the specimen reaches the specified bending degree or fracture occurs. The equipment used is an MTS E45 testing machine. The two support points at the bottom of the specimen are spaced 100 mm apart, with the loading end positioned at the center of the upper portion of the specimen. Loading is performed at a rate of 1 mm / min. During the test, if the composite sheet first debonds between the fixed plate and the foam metal plate, this indicates poor bonding. The test results are shown in Table 2.

[0143] Heat absorption performance test: The prepared composite sheet was applied to a battery case and tested at a high rate (average 3.6C) fast charge condition to measure the maximum temperature of the battery cells within the battery system at the end of the charge cycle. The test results are shown in Table 3. The maximum operating temperature of a lithium battery should not exceed 55°C. If the temperature remains above 55°C for a long time, the battery's cycle and calendar life will deteriorate, affecting its usability.

[0144] Table 1

[0145]

[0146]

[0147] Table 2

[0148]

[0149] Table 3

[0150] Numbering Fast charging end cell maximum temperature T max ]]> Example 1 46.2℃ Example 2 43.9℃ Example 3 48.4℃ Example 4 41.7℃ Example 5 49.3℃ Example 6 57.6℃ Example 7 44.2℃ Example 8 47.1℃ Comparative Example 1 44.9℃ Comparative Example 2 60.4℃ Comparative Example 3 65.7℃ Comparative Example 4 45.8℃

[0151] From the table above we can see that:

[0152] (1) Compared with Examples 4-5, it can be seen that in this application, by controlling the porosity of the foam metal, the composite plate has both weight advantage and energy absorption effect (≥1.5MJ / m 3 ).

[0153] (2) Example 1 compared with Examples 6-7, it can be seen that the present application has both energy absorption effect and heat dissipation capacity by controlling the equivalent diameter of the hole.

[0154] (3) Example 1 compared with Example 8, it can be seen that the present application effectively improves the bonding effect by phosphoric acid scrubbing on the side of the fixed plate coated with inorganic adhesive.

[0155] (4) Example 1 compared with Comparative Example 1, it can be seen that the present application is based on closed-cell foam metal, which has excellent structural strength compared to open-cell foam metal. Then by modification, the relatively independent semi-closed cells and closed cells in the closed-cell foam metal are connected, so that more phase change materials can be filled under the premise of ensuring the structural strength of the foam metal, thereby improving the compressive strength and elastic modulus of the closed-cell foam metal, and having high heat dissipation and other characteristics.

[0156] Example 1 compared with Comparative Examples 2-3, it can be seen that the phase change material effectively reduces the temperature rise under the condition of fast charging of the battery, so that the temperature at the end of charging does not exceed the upper limit of the use temperature of the battery.

[0157] (5) Example 1 compared with Comparative Example 4, it can be seen that in the present application, inorganic adhesive is used, which can realize chemical bonding and physical bonding during bonding, and the two bonding methods effectively improve the bonding strength between the foam metal plate and the fixed plate.

[0158] The technical features of the above-described embodiments can be combined arbitrarily. In order to make the description simple, all possible combinations of the technical features in the above-described embodiments are not described, but as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the present application.

[0159] The above-described embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, some modifications and improvements can be made, which are all within the scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A foam metal plate, characterized in that: The foam metal plate includes modified closed-cell foam metal and phase change material; The modified closed-cell metal foam is provided with a plurality of closed cells and a plurality of semi-closed cells provided on the surface of the modified closed-cell metal foam. A plurality of holes are provided on the cell walls of the closed cells and the cell walls of the semi-closed cells. The holes are formed by at least one of sandblasting, fracturing, and etching. The equivalent diameter of the holes is 0.05 mm to 1.20 mm. The holes are used to connect adjacent closed cells, adjacent semi-closed cells, and adjacent closed cells and semi-closed cells. The phase change material is filled in the closed cells, the semi-closed cells and the holes.

2. The foam metal plate according to claim 1, wherein The pores include at least one of a hole structure and a crack structure.

3. The foam metal plate according to claim 1 or 2, characterized in that: The foam metal plate also satisfies at least one of the following conditions: (1) The phase change material comprises at least one of a crystalline hydrated salt, a fatty acid, a polyol, and a paraffin; (2) The material of the modified closed-cell foam metal includes at least one of aluminum, aluminum alloy, copper, copper alloy, nickel and nickel alloy.

4. A method for preparing the foam metal plate according to any one of claims 1 to 3, characterized in that: The preparation method of the foam metal plate comprises: performing a modification treatment on the closed-cell metal foam, the modification treatment comprising at least one of a sandblasting method, a fracturing method, and an etching method, forming holes on the inner walls of the closed cells and the inner walls of the semi-closed cells in the closed-cell metal foam, the holes connecting adjacent closed cells, adjacent semi-closed cells, and adjacent semi-closed cells and closed cells, the equivalent diameter of the holes being 0.05 mm to 1.20 mm, to obtain a modified closed-cell metal foam; The phase change material is filled into the closed cells, the semi-closed cells and the holes.

5. The method for preparing the foam metal plate according to claim 4, wherein: The method for preparing the foam metal plate satisfies at least one of the following conditions: (1) The porosity of the closed-cell metal foam is 70% to 90%; (2) The equivalent diameter of the semi-closed cells is 1.0 mm to 5.0 mm; (3) The equivalent diameter of the closed cells is 1.0 mm to 5.0 mm; (4) The method of filling the phase change material includes at least one of an impregnation method and a casting method; optionally, the impregnation method includes a vacuum impregnation method; (5) After the phase change material is filled into the modified closed-cell metal foam, the surface is cleaned to remove the phase change material on the surface of the modified closed-cell metal foam.

6. A composite board, characterized in that: The composite plate comprises the foam metal plate according to any one of claims 1 to 3, and fixing plates arranged on opposite sides of the foam metal plate; An inorganic adhesive layer is provided between the fixing plate and the foam metal plate.

7. The composite plate according to claim 6, wherein: The composite plate meets at least one of the following conditions: (1) The fixing plate is provided with a mechanical connection structure, and the mechanical connection structure is used to fix the foam metal plate; (2) A strengthening connection layer is provided on the surface of the fixing plate on one side close to the inorganic adhesive layer; (3) The material of the inorganic adhesive layer includes at least one of phosphate adhesive, silicate adhesive, sulfate adhesive and borate adhesive.

8. The composite plate according to claim 7, wherein: The mechanical connection structure includes a surrounding plate arranged at the edge of the fixed plate.

9. The composite plate according to claim 7, wherein: The surface of the strengthening connection layer has a rough surface structure.

10. A method for preparing the composite board according to any one of claims 6 to 9, characterized in that: The preparation method of the composite plate comprises: The fixing plate and the foam metal plate are connected by using an inorganic adhesive to prepare the composite plate.

11. The method for preparing a composite plate according to claim 10, wherein: Before connecting the fixing plate to the foam metal plate, a surface treatment is performed on a surface of the fixing plate on which the fixing plate and the foam metal plate are bonded.

12. The method for preparing a composite plate according to claim 11, wherein: The surface treatment method includes: scrubbing the surface of the fixing plate with phosphoric acid to form a phosphate film with a rough surface on the surface of the fixing plate.

13. A battery box, characterized in that: The battery case comprises the composite plate material according to any one of claims 6 to 9.

Images