Lightweight integrated liquid cooling channel composite battery tray

Abstract

The present application relates to the field of racks, modules or assemblies for multiple batteries or multiple battery cells, and in particular to a lightweight integrated liquid cooling channel composite battery tray, comprising a framework, a bottom plate and a skin; wherein the framework is spliced from a profile; the bottom plate is fixedly connected to the framework, and the inside of the bottom plate is provided with a liquid cooling channel; the skin is wrapped on the outer surfaces of the framework and the bottom plate, and is tightly bonded with the framework and the bottom plate through a solidification process and is combined into an integral structure. The liquid cooling channel of the present application is directly integrated in the inside of the bottom plate, rather than using an independent liquid cooling plate, which significantly reduces the overall thickness of the bottom plate, and the bottom plate, the framework and the skin are integrally formed through the solidification process of the skin, without the need for welding, bolts and rivets, thereby simplifying the manufacturing process and reducing the manufacturing cost.

Description

Technical Field

[0001] This invention relates to the field of racks, modules or components for multiple batteries or multiple battery cells, and more specifically to a lightweight integrated liquid-cooled flow channel composite battery tray. Background Technology

[0002] Battery trays typically include a base plate for supporting battery modules and a frame surrounding the base plate. In the prior art, battery trays are mostly made of aluminum alloy extruded profiles that are welded or bolted together. In order to achieve thermal management functions, traditional battery trays usually adopt an independent liquid cooling plate design, that is, an additional metal plate with brazed flow channels is installed at the bottom of the battery tray, or the liquid cooling pipes are glued to the base plate with thermally conductive adhesive.

[0003] This traditional structure has significant drawbacks: the all-metal structure has a high density, which makes it difficult to meet the lightweight requirements of new energy vehicles; the independent liquid cooling system makes the overall structure of the battery tray complex, occupies a large space in the height direction, and there are assembly tolerances and contact gaps between the metal liquid cooling plate and the bottom plate of the battery tray, resulting in high contact thermal resistance and low heat exchange efficiency. Summary of the Invention

[0004] The purpose of this invention is to provide a lightweight integrated liquid-cooled flow channel composite material battery tray, which aims to solve the problems of complex structure, large space occupation, and low heat exchange efficiency of traditional battery tray independent liquid cooling systems.

[0005] To solve the above-mentioned technical problems, the present invention specifically provides the following technical solution: A lightweight integrated liquid-cooled flow channel composite battery tray, comprising: The frame is constructed by splicing together profiles. A base plate is fixedly connected to the frame, and the base plate has a liquid cooling channel inside; Skin, covering the outer surfaces of the skeleton and the base plate; The skin is tightly bonded to the frame and the base plate through a curing process and integrated into a single structure.

[0006] Furthermore, a flow channel groove is formed on the upper surface of the base plate; The liquid cooling channel is made of a metal tube, and the metal tube is embedded entirely in the channel groove. The space between the metal tube and the flow channel is filled with thermally conductive structural adhesive. The skin covers the upper surface of the base plate and the top of the metal tube.

[0007] Furthermore, a flow channel groove is formed on the upper surface of the base plate; The inner surface of the flow channel forms the bottom wall and side wall of the liquid cooling flow channel; The skin spans and closes the top opening of the flow channel, and the inner surface of the skin facing the flow channel forms the top wall of the liquid cooling flow channel.

[0008] Furthermore, the skin includes the substrate made of resin-based fiber-reinforced prepreg, and an inner liner adhered to the bottom wall of the substrate, the inner liner being an adhesive film or resin-rich felt, the inner liner forming the top wall of the liquid cooling channel.

[0009] Furthermore, the base plate is made of foamed material.

[0010] Furthermore, the base plate is made of foamed material; The bottom and side walls of the liquid cooling channel have a dense hardened layer, the density of which is higher than the overall density of the foamed material. The dense hardened layer is formed during the foaming process of the base plate by pre-applying a foaming inhibitor at the forming part of the liquid cooling channel.

[0011] Furthermore, the wall of the flow channel is covered with a continuous leak-proof layer, the leak-proof layer being a gel coat layer or a thermoplastic film layer, and the leak-proof layer is integrally bonded to the base plate; The leak-proof layer has an inwardly folded flange that extends horizontally toward the center of the flow channel at the top edge of the flow channel. The skin is pressed against the inner flange and forms a surface overlap seal with the leak-proof layer.

[0012] Furthermore, metal connectors are provided at the inlet and outlet of the flow channel; The metal joint includes a connecting section exposed outside the flow channel and an anchoring section embedded inside the flow channel. The anchoring section is flat, and the connecting section is provided with a thrust flange, which is embedded inside the base plate, and the skin covers the connecting section.

[0013] Furthermore, a positioning groove is provided on the upper surface of the base plate, and the bottom of the frame is fitted into the positioning groove.

[0014] Furthermore, the profile is a pultruded resin-based glass fiber composite material.

[0015] The advantages of this invention compared to the prior art include: The liquid cooling channels are directly integrated into the interior of the base plate, rather than using a separate liquid cooling plate, which significantly reduces the overall thickness of the base plate. Furthermore, the base plate, frame, and skin are integrally formed through the skin curing process, eliminating the need for welding, bolts, and rivets, thus simplifying the manufacturing process and reducing manufacturing costs. Attached Figure Description

[0016] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0017] Figure 1 This is an assembly diagram of the skeleton according to the first embodiment of the present invention; Figure 2 This is a perspective view of the skeleton of the first embodiment of the present invention; Figure 3 This is an assembly diagram of the first embodiment of the present invention; Figure 4 This is a perspective view of the first embodiment of the present invention, in which the skin is transparent; Figure 5 This is a top view of the first embodiment of the present invention; Figure 6 for Figure 5 A cross-sectional view along the AA direction; Figure 7 This is a perspective view of the base plate of the second embodiment of the present invention, and an enlarged view of its partial structure; Figure 8 This is a perspective view of the base plate of the third embodiment of the present invention, and an enlarged view of its partial structure; Figure 9 This is a perspective view of the base plate of the fourth embodiment of the present invention, and an enlarged view of its partial structure; The labels in the diagram represent the following: 1-Frame; 11-Profile; 2-Base plate; 21-Flow channel; 22-Leak-proof layer; 23-Inner flange; 24-Positioning groove; 3-Skin; 4-Metal tube; 5-Metal joint; 51-Connecting section; 52-Anchoring section; 53-Thrust flange; 6-Sacrificial core mold. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] (First Embodiment) To solve the problems of the conventional independent liquid cooling system of the traditional battery tray in the prior art, such as complex structure, large occupied space and low heat exchange efficiency, the present invention proposes a lightweight composite material battery tray with integrated liquid cooling flow channels, the core technology of which lies in: 1. The frame 1 of the battery tray is formed by splicing a plurality of profiles 11 made of pultruded resin-based glass fiber composite material.

[0020] 2. The liquid cooling flow channel is directly formed inside the bottom plate 2 of the battery tray.

[0021] 3. The skin 3 covers the surfaces of the frame 1 and the bottom plate 2 (including the top wall, the bottom wall and the peripheral wall), and is tightly bonded to the frame 1 and the bottom plate 2 through a curing process to form an integral structure.

[0022] The advantages of the above design lie in: 1. For the frame 1 manufactured by the pultrusion process, the fibers are oriented and arranged along the force direction, so that the frame 1 has high axial specific strength and specific modulus, which ensures the rigidity requirement of the battery tray under collision conditions while greatly reducing the weight (more than 40% weight reduction compared with aluminum alloy); in addition, the frame 1 made of composite material is naturally corrosion-resistant, insulating, and has a small thermal expansion coefficient, which improves the overall safety of the battery pack.

[0023] 2. The liquid cooling flow channel is directly integrated inside the bottom plate 2 instead of using an independent liquid cooling plate, which significantly reduces the overall thickness of the bottom plate 2.

[0024] 3. The bottom plate 2, the frame 1 and the skin 3 are integrally formed through a co-curing process, without the need for processes such as welding, bolts and rivets, which simplifies the manufacturing process and reduces the manufacturing cost on the premise of meeting the structural strength.

[0025] Reference Figure 1 and Figure 2 , the manufacturing process of the frame 1 includes the following steps: adopting a continuous pultrusion process, drawing the alkali-free glass fiber yarn or mat impregnated with a resin mixture (such as epoxy resin or polyurethane resin) through a heating mold (the temperature is usually controlled at 120-180°C), and curing and forming into a beam body with a preset cross-section (such as rectangular, double-frame shape or square shape).

[0026] Reference Figure 3 and Figure 4 , the co-curing process includes the following steps: after the frame 1 and the bottom plate 2 (including the liquid cooling flow channel) are assembled into a whole, covering the top surface and the bottom surface thereof with the skin 3 (resin-based fiber-reinforced prepreg), then placing the whole into a hot pressing mold, and connecting the frame 1, the bottom plate 2 and the skin 3 through hot pressing by co-curing, so as to form an integral body.

[0027] Reference Figure 5 and Figure 6 In this embodiment, the base plate 2 is made of foamed material, and the upper surface of the base plate 2 is provided with flow channel groove 21 and positioning groove 24 (e.g., milled). The bottom shape of the skeleton 1 matches the positioning groove 24.

[0028] The liquid cooling channel is made of a metal tube 4, which has a preset curved shape (such as a snake) and is embedded in the channel groove 21 opened on the upper surface of the foam material base plate 2. Thermally conductive structural adhesive is filled between the metal tube 4 and the channel groove 21. The thermally conductive structural adhesive is used to fix the metal tube 4 and eliminate the air gap between the metal tube 4 and the channel groove 21 to enhance heat conduction.

[0029] The two ends of the metal tube 4 extend to the edge or outer side of the base plate 2 and are processed into the shape of a circular metal connector 5. The part of the metal tube 4 located on the inner side of the base plate 2 is stamped into a flat shape.

[0030] The liquid cooling channel is fabricated through the following steps: Step 1, Metal Tube 4 Forming: The tube is processed into the preset flow channel shape by a CNC tube bending machine, and the tube end forming treatment (such as flaring) and tube body shaping treatment (such as pressing into a flat cross section) are carried out.

[0031] Step 2, milling: Use a CNC machine tool to mill a flow channel groove 21 on the upper surface of the base plate 2 to match the path of the metal tube 4. The depth of the flow channel groove 21 is equal to or slightly greater than the thickness of the metal tube 4 to ensure that the metal tube 4 does not protrude from the surface of the base plate 2 after being embedded.

[0032] Step 3, Embedding and Filling: Apply thermally conductive structural adhesive to the milled flow channel 21, press the formed metal tube 4 into the flow channel 21, and scrape off any overflowing adhesive.

[0033] Step 4, Skin 3 covering and co-curing molding: Assemble the frame 1 and the base plate 2 with the embedded metal tube 4. The frame 1 is pre-positioned and fixed by fitting into the positioning groove 24. Then, skin 3 is laid on the outer surface of the frame 1 and the base plate 2. The frame 1, the base plate 2 and skin 3 are sent into the molding equipment for hot pressing and curing. Skin 3 forms a hard shell, pressing the frame 1, the base plate 2 and the metal tube 4 inside into a whole.

[0034] In addition, refer to Figure 7 , Figure 8 and Figure 9 The liquid cooling channel can be formed inside the base plate 2 of the battery tray using the processes described in the other three embodiments.

[0035] (Second Embodiment) refer to Figure 7In this embodiment, the base plate 2 is made of foamed material, and the upper surface of the base plate 2 is provided with a flow channel groove 21 (e.g., milled). The flow channel groove 21 constitutes the bottom wall and side wall of the liquid cooling channel. The inner surface of the skin 3 covering the upper surface of the base plate 2 directly crosses and closes the top opening of the flow channel groove 21, thereby constituting the top wall of the liquid cooling channel.

[0036] Metal connectors 5 are provided at the inlet and outlet of the liquid cooling channel. The metal connectors 5 have a circular connecting section 51 (exposed outside the battery tray) and a flat anchoring section 52 (embedded in the battery tray). The anchoring section 52 is fixed to the port of the channel groove 21 by structural adhesive, and the skin 3 covers the connection between the connector and the channel to assist in sealing.

[0037] The liquid cooling channel is fabricated through the following steps: Step 1, Metal Joint 5 Formation: The pipe is formed into metal joint 5 by performing pipe end forming treatment (such as flaring one end and flattening the other end).

[0038] Step 2, milling: Use a CNC machine tool to mill a flow channel groove 21 with a preset pattern (such as a snake) on the upper surface of the base plate 2, and mill the mounting position of the metal connector 5 at the end of the flow channel groove 21.

[0039] Step 3, Install the connector: Apply thermally conductive structural adhesive to the milled flow channel groove 21, press the anchoring section 52 of the formed metal connector 5 into the flow channel groove 21, and scrape off any overflowing adhesive.

[0040] Step 4, Skin 3 covering and co-curing molding: Assemble the skeleton 1 and the base plate 2 with embedded metal joints 5. Then, lay the skin 3 on the outer surface of the skeleton 1 and the base plate 2. The skin 3 is laid directly above the top opening of the flow channel 21 (the skin 3 is preferably a high-viscosity prepreg to prevent collapse). Send the skeleton 1, the base plate 2 and the skin 3 into the molding equipment for hot pressing and curing. The skin 3 forms a hard shell, pressing the skeleton 1, the base plate 2 and the metal tube 4 inside into a whole. At the same time, the skin 3 is bonded to the base plate 2 and seals the top opening of the flow channel 21 to form a liquid cooling flow channel.

[0041] In a preferred embodiment, to further improve the smoothness and sealing of the top wall of the flow channel, the skin 3 used is a composite structure, comprising a substrate made of resin-based fiber-reinforced prepreg and an inner liner pre-attached to the bottom surface of the substrate (facing the flow channel 21). This inner liner can be a film or a resin-rich felt. During installation, the inner liner directly contacts the opening of the flow channel 21, forming the inner surface of the top wall of the liquid-cooled flow channel.

[0042] (Third embodiment) refer to Figure 8 The third embodiment differs from the second embodiment in that: The base plate 2 is made of foamed material. During the foaming process of the base plate 2, the upper surface directly forms a flow channel groove 21, which constitutes the bottom wall and side wall of the liquid cooling flow channel.

[0043] In addition, metal connectors 5 are provided at the inlet and outlet of the liquid cooling channel, and the inner surface of the skin 3 covering the upper surface of the base plate 2 directly crosses over and closes the top opening of the channel groove 21, thus forming the top wall of the liquid cooling channel.

[0044] The inner wall of the flow channel 21 is a dense hardened layer with a density significantly higher than that of the base plate 2, which strengthens the sidewall of the liquid cooling flow channel and prevents coolant from seeping into the foam pores.

[0045] The liquid cooling channel is fabricated through the following steps: Step 1, make sacrificial core mold 6: The shape of sacrificial core mold 6 corresponds to the shape of the liquid cooling channel, and sacrificial core mold 6 has water solubility or heat fusion properties.

[0046] Step 2, install metal connector 5: The pipe is formed by end forming (e.g., one end is flared and the other end is flattened) to form metal connector 5. Then the metal connector 5 is installed at the end of the sacrificial mandrel 6. In particular, the flattened end of the metal connector 5 is formed with a thrust flange 53.

[0047] Step 3, in-situ foaming and wrapping: A foaming inhibitor (one or more combinations of silicone defoamers, mineral oil defoamers, or polyether defoamers can be selected) is pre-placed on the outer surface of the sacrificial core mold 6; then the sacrificial core mold 6 with the metal connector 5 is placed into the mold for foaming. During the foaming process, the foaming inhibitor inhibits the foaming material, and a high-density, dense, hardened layer is formed by the foam closely adhering to the sacrificial core mold 6; after foaming is completed, a base plate 2 with the sacrificial core mold 6 and the metal connector 5 is formed.

[0048] Step 4, Surface milling and exposure of sacrificial core mold 6: Use milling equipment to flatten the upper surface of the foamed base plate 2, control the milling depth, grind away the foam layer covering the sacrificial core mold 6 until the top surface of the sacrificial core mold 6 is exposed, so that the upper surface of the base plate 2 and the top surface of the sacrificial core mold 6 form a continuous flat plane.

[0049] Step 5, Skin 3 covering and co-curing molding: Assemble the skeleton 1 and the base plate 2 with the sacrificial core mold 6 embedded. Then, lay the skin 3 on the outer surface of the skeleton 1 and the base plate 2. The skin 3 is laid directly on top of the sacrificial core mold 6. Send the skeleton 1, the base plate 2 and the skin 3 into the molding equipment for hot pressing and curing. The skin 3 forms a hard shell, pressing the skeleton 1, the base plate 2 and the sacrificial core mold 6 inside into a whole.

[0050] Step 6, Liquid Cooling Channel Forming: After co-curing, water is injected or heated through the metal connector 5 to dissolve or melt the internal sacrificial core mold 6 and discharge it, forming a dense liquid cooling channel with an inner wall.

[0051] (Fourth embodiment) refer to Figure 9 The fourth embodiment differs from the third embodiment in that: The bottom and side walls of the flow channel 21 are covered with a continuous leak-proof layer 22 (such as a glass fiber gel coat layer or a thermoplastic film layer). The leak-proof layer 22 is integral with the base plate 2 and extends to the surface of the anchoring section 52 of the metal joint 5.

[0052] The leak-proof layer 22 forms an inwardly folded flange 23 extending horizontally towards the center of the liquid cooling channel at the top edge of the liquid cooling channel. The skin 3 covers the liquid cooling channel and presses against the inwardly folded flange 23, so that the skin 3 and the leak-proof layer 22 achieve a surface-to-surface overlapping seal.

[0053] The liquid cooling channel is fabricated through the following steps: Step 1, make sacrificial core mold 6: The shape of sacrificial core mold 6 corresponds to the shape of liquid cooling channel. Sacrificial core mold 6 is water-soluble or heat-meltable. In particular, an upward protruding boss is pre-designed at the middle position of the top of sacrificial core mold 6, and a step connecting the boss is formed at the edge of the top of sacrificial core mold 6.

[0054] Step 2, install metal connector 5: The pipe is formed by end forming (e.g., one end is flared and the other end is flattened) to form metal connector 5, and then the metal connector 5 is installed at the end of the sacrificial mandrel 6.

[0055] Step 3, Cover with leak-proof layer 22: Apply / cover the leak-proof layer 22 on the surface of the sacrificial core mold 6 and the surface of the anchoring section 52 of the metal joint 5. The leak-proof layer 22 not only covers the bottom and sides of the sacrificial core mold 6, but also extends to cover the side wall of the top boss of the core mold and the top edge of the boss.

[0056] Step 4, in-situ foaming: The sacrificial core mold 6 covered with the leak-proof layer 22 and the metal connector 5 are placed into the mold for foaming to form a base plate 2 with the sacrificial core mold 6 and the metal connector 5 fitted together.

[0057] Step 5, Surface milling and exposure of sacrificial core mold 6: The upper surface of the base plate 2 is milled and flattened, and the milling depth is set. After exposing the top surface of the sacrificial core mold 6, the boss of the sacrificial core mold 6 is ground away until the anti-leakage layer 22 on the step of the sacrificial core mold 6 is exposed, so that the anti-leakage layer 22 covering the bottom wall, side wall and step of the sacrificial core mold 6 forms an inwardly folded flange 23, and at the same time the top surface of the main body of the sacrificial core mold 6 is exposed.

[0058] Step 6, Skin 3 covering and co-curing molding: Assemble the skeleton 1 and the base plate 2 with the sacrificial core mold 6 embedded. Then, lay the skin 3 on the outer surface of the skeleton 1 and the base plate 2. The skin 3 is laid directly on top of the sacrificial core mold 6 and pressed on the newly formed inner flange 23 to form a reliable overlap seal. Send the skeleton 1, the base plate 2 and the skin 3 into the molding equipment for hot pressing and curing. The skin 3 forms a hard shell, pressing the skeleton 1, the base plate 2 and the sacrificial core mold 6 inside into a whole.

[0059] Step 7, Liquid Cooling Channel Forming: After co-curing, water is injected or heated through the metal connector 5 to dissolve or melt the internal sacrificial core mold 6 and discharge it, forming a liquid cooling channel with a leak-proof layer 22.

[0060] The above embodiments are merely exemplary embodiments of the present invention and are not intended to limit the present invention. The scope of protection of the present invention is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to the present invention within its spirit and scope of protection, and such modifications or equivalent substitutions should also be considered as falling within the scope of protection of the embodiments of the present invention.

Claims

1. A lightweight integrated liquid-cooled flow channel composite material battery tray, characterized in that, include: The frame (1) is assembled from profiles (11); The base plate (2) is fixedly connected to the frame (1), and the interior of the base plate (2) is provided with liquid cooling channels; Skin (3) covers the outer surfaces of the skeleton (1) and the base plate (2); The skin (3) is tightly bonded to the frame (1) and the base plate (2) through a curing process and combined into an integrated structure.

2. The lightweight integrated liquid-cooled flow channel composite material battery tray according to claim 1, characterized in that, The upper surface of the base plate (2) is provided with a flow channel groove (21); The liquid cooling channel is composed of a metal tube (4), which is embedded entirely in the channel groove (21); The space between the metal tube (4) and the flow channel (21) is filled with thermally conductive structural adhesive; The skin (3) covers the upper surface of the base plate (2) and the top of the metal tube (4).

3. The lightweight integrated liquid-cooled flow channel composite material battery tray according to claim 1, characterized in that, The upper surface of the base plate (2) is provided with a flow channel groove (21); The inner surface of the flow channel (21) forms the bottom wall and side wall of the liquid cooling flow channel; The skin (3) spans and closes the top opening of the flow channel (21), and the inner surface of the skin (3) facing the flow channel (21) forms the top wall of the liquid cooling flow channel.

4. The lightweight integrated liquid-cooled flow channel composite material battery tray according to claim 3, characterized in that, The skin (3) includes a substrate made of resin-based fiber-reinforced prepreg and an inner liner adhered to the bottom wall of the substrate, the inner liner being a film or resin-rich felt, the inner liner forming the top wall of the liquid cooling channel.

5. The lightweight integrated liquid-cooled flow channel composite material battery tray according to claim 1 or 2, characterized in that, The base plate (2) is made of foam material.

6. The lightweight integrated liquid-cooled flow channel composite material battery tray according to claim 3 or 4, characterized in that, The base plate (2) is made of foam material; The bottom and side walls of the liquid cooling channel have a dense hardened layer, the density of which is higher than the overall density of the foamed material. The dense hardened layer is formed during the foaming process of the base plate (2) by pre-placing a foaming inhibitor in the molding part of the liquid cooling channel.

7. The lightweight integrated liquid-cooled flow channel composite material battery tray according to claim 3 or 4, characterized in that, The wall of the flow channel (21) is covered with a continuous leak-proof layer (22), the material of the leak-proof layer (22) is a gel coat layer or a thermoplastic film layer, and the leak-proof layer (22) is integrally combined with the base plate (2); The leak-proof layer (22) has an inwardly folded flange (23) that extends horizontally toward the center of the channel groove (21) at the top edge of the channel groove (21). The skin (3) presses against the inner flange (23) and forms a surface overlap seal with the leak-proof layer (22).

8. The lightweight integrated liquid-cooled flow channel composite material battery tray according to claim 3, characterized in that, The inlet and outlet of the flow channel (21) are provided with metal connectors (5); The metal connector (5) includes a connecting section (51) exposed outside the flow channel (21) and an anchoring section (52) embedded inside the flow channel (21). The anchoring section (52) is flat and is provided with a thrust flange (53). The thrust flange (53) is embedded inside the base plate (2), and the skin (3) covers the connecting section (51).

9. The lightweight integrated liquid-cooled flow channel composite material battery tray according to claim 1, characterized in that, The upper surface of the base plate (2) is provided with a positioning groove (24), and the bottom of the frame (1) is fitted into the positioning groove (24).

10. The lightweight integrated liquid-cooled flow channel composite material battery tray according to claim 1, characterized in that, The profile (11) is a pultruded resin-based glass fiber composite material.

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