Lower box body of composite material sandwich plate battery box

Abstract

The utility model provides a composite sandwich panel battery box lower box body, which comprises a bottom plate and a side plate, the bottom plate comprises a carbon fiber upper panel, an upper adhesive film, a honeycomb core, a lower adhesive film and a carbon fiber lower panel which are laminated in sequence, a plurality of I-shaped threaded inserts are pre-embedded in the periphery of the bottom plate and are used for being connected with an automobile chassis, a battery module mounting part is arranged on the bottom plate, and a battery module is arranged on the side plate. A plurality of II-type threaded inserts are pre-embedded in the shell and are used for being connected with a battery module; and the side plates and the bottom plate in multiple directions are encircled and fixedly connected to form a lower box body of the composite sandwich plate battery box. According to the scheme, the weight of the battery box can be reduced while the strength of the battery box is improved, so that the purposes of saving energy and reducing the manufacturing cost are achieved.

Description

Technical Field

[0001] The present application relates to the field of new energy vehicles, and more specifically, to a lower box body of a battery box made of a composite sandwich panel. Background Art

[0002] Traditional battery boxes are made of metal through welding or casting, making them bulky and heavy, which increases the weight of the vehicle. Studies have shown that every 1% reduction in vehicle weight can reduce fuel consumption by 6%, so research and manufacturing of lightweight battery boxes is of great significance.

[0003] Currently, there are composite battery boxes based on laminates on the market, which greatly reduce the weight of the battery box compared to metal battery boxes. Although the composite material has a high modulus in the fiber direction, the bending stiffness is relatively low. Therefore, in order to reduce the deformation of the battery box, the wall panels of the battery box need to be made very thick, which increases the weight of the battery box and increases the production cost of the battery box. Utility Model Content

[0004] The purpose of the embodiments of the present application is to provide a composite sandwich panel battery box lower box to improve the strength of the battery box while reducing the weight of the battery box, thereby achieving the purpose of energy saving and reducing manufacturing costs.

[0005] In order to achieve the above objectives, the embodiments of the present application are implemented in the following manner:

[0006] In the first aspect, an embodiment of the present application provides a lower box body of a composite sandwich panel battery box, comprising a bottom plate and side plates, the bottom plate comprising a carbon fiber upper panel, an upper adhesive film, a honeycomb core, a lower adhesive film and a carbon fiber lower panel laminated in sequence, and a number of type I threaded inserts are pre-embedded around the bottom plate for connecting to the chassis of a car, a battery module mounting portion is provided on the bottom plate, and a number of type II threaded inserts are pre-embedded for connecting to the battery module; the side plates in multiple directions are surrounded and fixedly connected to the bottom plate to form the lower box body of the composite sandwich panel battery box.

[0007] In combination with the first aspect, in a first possible implementation of the first aspect, the thickness of the carbon fiber upper panel and the carbon fiber lower panel is 1-3 mm.

[0008] In combination with the first aspect, in a second possible implementation of the first aspect, the honeycomb core is made of an aluminum alloy honeycomb material with a thickness of 15-25 mm.

[0009] In combination with the first aspect, in a third possible implementation of the first aspect, the side panels are made of a composite material structure with a thickness of 3-5 mm.

[0010] In combination with the first aspect, in a fourth possible implementation of the first aspect, a through-hole type mounting hole area is opened around the base plate, and the I-type threaded insert includes a resin-short carbon fiber composite material layer and a wire screw sleeve. The wire screw sleeve and the resin-short carbon fiber composite material layer are fixedly arranged in the through-hole type mounting hole area, and the resin-short carbon fiber composite material layer has an internal threaded through hole, and the wire screw sleeve is fixedly installed in the internal threaded through hole.

[0011] In combination with the first aspect, in a fifth possible implementation of the first aspect, a blind hole type mounting hole area is opened in the battery module mounting portion, and the Type II threaded insert includes a resin-short carbon fiber composite material layer and a wire screw sleeve. The wire screw sleeve and the resin-short carbon fiber composite material layer are fixedly arranged in the blind hole type mounting hole area, and the resin-short carbon fiber composite material layer has an internal threaded hole opened, and the wire screw sleeve is fixedly installed in the internal threaded hole.

[0012] In combination with the first aspect, in a sixth possible implementation of the first aspect, the battery module mounting portion is glued and cured with a carbon fiber laminate.

[0013] In combination with the first aspect, in the seventh possible implementation of the first aspect, the area where the battery module mounting portion is located is distributed along the edge of the internal area enclosed by the side panel and the bottom plate, and the battery module placement area is formed by the area where the battery module mounting portion is located, and the thickness of the bottom plate in the area where the battery module mounting portion is located is greater than the thickness in the battery module placement area.

[0014] In combination with the first aspect, in an eighth possible implementation manner of the first aspect, the carbon fiber upper panel of the bottom plate is integrally formed with the side panels in multiple directions.

[0015] Beneficial effects: 1. The lower body of the composite sandwich battery box in this solution includes a bottom plate and side plates. The bottom plate includes a carbon fiber upper panel, an upper adhesive film, a honeycomb core, a lower adhesive film and a carbon fiber lower panel laminated in sequence, and a number of type I threaded inserts are pre-embedded around the bottom plate for connection with the vehicle chassis. A battery module mounting portion is provided on the bottom plate, which is pre-embedded with a number of type II threaded inserts for connection with the battery module; the side panels in multiple directions are surrounded and fixedly connected to the bottom plate to form the lower body of the composite sandwich battery box. The lower body of the composite sandwich battery box is realized by a composite plate with a carbon fiber composite panel honeycomb sandwich core. The sandwich structure is composed of five parts: an upper panel, an adhesive layer between the upper panel and the core material, a core material, an adhesive layer between the lower panel and the core material, and a lower panel (i.e., a carbon fiber upper panel, an upper adhesive film, a honeycomb core, a lower adhesive film and a carbon fiber lower panel). The upper and lower panels are made of molded carbon fiber, and the interlayer is made of a low-density aluminum honeycomb core. The use of composite materials in battery boxes leverages their molding advantages, simplifying the process and enabling the creation of structures difficult to achieve with traditional machining methods. Utilizing composite curing and molding processes, the battery box can be integrally molded, reducing the number of components and joints, improving structural reliability, and reducing weight. The sandwich structure positions high-strength, high-modulus carbon fiber panels away from the neutral axis to withstand compressive and tensile forces. A lightweight aluminum honeycomb core separates the panels, increasing their bending stiffness. Threaded inserts embedded in the panels connect to the battery modules (i.e., the baseplate includes a battery module mounting area with several Type II threaded inserts embedded in the panels for connection). This ensures connection strength while significantly simplifying the manufacturing process and reducing costs. This composite design significantly reduces the weight of the battery box. Furthermore, the excellent flame retardancy of the carbon fiber panels significantly enhances the safety of the battery box. Several Type I threaded inserts embedded around the baseplate for connection to the vehicle chassis enhance the connection strength, reduce weight, and reduce processing costs.

[0016] 2. This solution glues and cures carbon fiber laminates at the battery module mounting part to strengthen the structure, avoid stress concentration at local joints, and improve the structural reliability of the battery box. The area where the battery module mounting part is located is distributed along the edge of the internal area enclosed by the side panels and the bottom panel. The battery module placement area is formed by the area where the battery module mounting part is located. The thickness of the bottom panel in the area where the battery module mounting part is located is greater than the thickness in the battery module placement area. By changing the proportion of local composite materials and honeycomb core materials, the thickness of the sandwich panel is increased in places with large loads, and the thickness of the sandwich panel is reduced in places with small loads, so that the materials can be reasonably distributed and arranged to maximize the utilization of the materials. By using carbon fiber laminates (upper and lower panels of the bottom panel, side panels, carbon fiber laminates glued and cured at the battery module mounting part, etc.) as the battery box body panels, the advantages of the good flame retardancy of carbon fiber materials can be brought into play, the phenomenon of battery box heating and fire can be reduced, and the safety of battery box use can be improved.

[0017] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 A top view of the lower box body of the composite sandwich panel battery box provided in an embodiment of the present application.

[0020] Figure 2 Schematic diagram of the lower box of the composite sandwich panel battery box provided in an embodiment of the present application.

[0021] Figure 3 Schematic diagram of installing a battery module in the lower box of a composite sandwich panel battery box provided in an embodiment of the present application.

[0022] Icons: 110-base plate; 111-Type I threaded insert; 112-carbon fiber laminate; 113-Type II threaded insert; 120-side panel; 200-battery module. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application.

[0024] In the description of this application, it should be noted that the terms "inner" and "outer" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or the orientations or positional relationships in which the product of this application is typically placed when in use. These terms are intended solely to facilitate the description of this application and simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first" and "second" and the like are used solely for distinction and should not be construed as indicating or implying relative importance.

[0025] It should also be noted that, unless otherwise expressly specified or limited, the terms "disposed" and "connected" should be understood broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0026] See also Figure 1-Figure 3 The lower box body of the composite sandwich panel battery box includes a bottom plate 110 and a side plate 120. The side plates 120 in multiple directions are surrounded and fixedly connected to the bottom plate 110 to form the lower box body of the composite sandwich panel battery box.

[0027] In this embodiment, the bottom plate 110 includes a carbon fiber upper panel, an upper adhesive film, a honeycomb core, a lower adhesive film, and a carbon fiber lower panel laminated in sequence.

[0028] The carbon fiber upper and lower panels have a thickness of 1-3mm, such as 1mm, 2mm, and 3mm. The upper and lower adhesive films are made of epoxy resin and have a thickness of 0.1mm to 0.2mm, such as 0.01mm. The honeycomb core is made of aluminum alloy honeycomb material and has a thickness of 15-25mm, such as 15mm, 18mm, and 25mm. These thickness parameters can be adjusted according to strength requirements.

[0029] Since the side panels 120 are mainly used to wrap the battery module 200 and connect the load-bearing upper box cover, the structure bears almost no load, and a composite material structure with a thickness of 3-5 mm (for example, 3 mm, 4 mm, 5 mm, etc.) can be used. The carbon fiber upper panel of the bottom plate 110 can be formed in one piece with the side panels 120 in multiple directions. Applying composite materials to battery boxes can give full play to the molding advantages of composite materials. The molding is simple and some structures that are difficult to achieve with traditional machining processes can be made. By utilizing the composite material curing molding process, the battery box can be integrally molded, the number of components and the connection structure can be reduced, the reliability of the battery box structure can be improved, and the weight of the battery box can be reduced to a certain extent.

[0030] In order to achieve the connection between the lower box of the composite sandwich panel battery box and the automobile chassis, this embodiment pre-embeds a number of I-type threaded inserts 111 around the bottom plate 110 (for example, this embodiment has 6 I-type threaded inserts 111, and the pre-embedded positions and quantities of the I-type threaded inserts 111 can be matched according to different vehicle models. The examples given in this embodiment should not be regarded as limitations on this application).

[0031] To pre-embed the I-shaped threaded insert 111, a through-hole mounting area (corresponding to the connection location on the vehicle chassis) is required around the base plate 110. The I-shaped threaded insert 111 comprises a resin-short carbon fiber composite material layer and a wire thread insert. The wire thread insert and the resin-short carbon fiber composite material layer are fixedly disposed within the through-hole mounting area. The resin-short carbon fiber composite material layer defines an internally threaded through-hole, and the wire thread insert is fixedly mounted within the internally threaded through-hole.

[0032] To improve connection strength, the through-hole mounting hole area includes an opening area and an inner layer area. The opening area is the opening portion of the through-hole mounting hole area on the carbon fiber upper panel and the carbon fiber lower panel, and the inner layer area is the opening portion of the mounting hole area formed on the honeycomb core. The aperture of each opening area is smaller than the aperture of the inner layer area. The outer diameter of the wire screw sleeve is less than or equal to the aperture of the opening area, and the ratio of the aperture of the inner layer area to the outer diameter of the wire screw sleeve does not exceed 2.

[0033] For example, when drilling holes in the middle honeycomb core (usually a hexagonal honeycomb structure), the surrounding honeycomb core structure will be damaged (making the pore diameter of the inner layer larger than the pore diameter of the open area). For example, if an M6 connecting bolt (with a 6mm outer diameter wire screw) is required, then a 9mm diameter hole can be drilled in the inner layer of the honeycomb core, which means that a 9mm diameter circle of the honeycomb core will be damaged during the drilling process.

[0034] After the punching is completed, there will be a through-hole type mounting hole area on the carbon fiber panel honeycomb sandwich structure for installing the threaded connection structure.

[0035] For example, the portion of the resin-short carbon fiber composite material layer that contacts the honeycomb core within the through-hole mounting hole area forms a resin honeycomb core bonding layer, while the remaining portion forms a co-cured resin layer of the short carbon fibers and resin. In conjunction with the above example, after the resin-short carbon fiber composite material is poured into the mounting hole area and formed, the damaged honeycomb core along a 9mm circle will form a resin honeycomb core bonding area (i.e., a resin honeycomb core bonding layer), while the carbon fiber-resin co-cured resin (i.e., a co-cured resin layer of the short carbon fibers and resin) will form from 6mm to 9mm. This helps to improve the connection strength of the I-type threaded insert 111.

[0036] According to actual needs, the proportion of short carbon fibers in the resin-short carbon fiber composite layer can be adjusted, generally between 10% and 60%. Specifically, the proportion of short carbon fibers can be adjusted according to strength requirements. The lower the proportion of short carbon fibers, the better the molding of the resin-short carbon fiber composite layer, but the strength will be reduced. Therefore, it is necessary to combine strength requirements and economic efficiency, and the specific ratio can be adjusted according to needs.

[0037] In order to install the battery module 200 , it is also necessary to design a battery module 200 installation portion on the base plate 110 and pre-embed a number of II-type threaded inserts 113 for connection with the battery module 200 .

[0038] like Figure 1 and Figure 2 As shown, the area where the battery module 200 mounting portion is located is distributed along the edge of the internal area enclosed by the side panels 120 and the bottom panel 110. The area where the battery module 200 mounting portion is located forms the battery module 200 placement area. The thickness of the bottom panel 110 in the area where the battery module 200 mounting portion is located is greater than the thickness in the battery module 200 placement area (this is achieved by adjusting the thickness of the honeycomb core in different areas. For example, the thickness of the honeycomb core in the battery module 200 placement area is 18 mm, and the thickness of the honeycomb core in the area where the battery module 200 mounting portion is located is 25 mm). By designing different thicknesses, the proportion of local composite materials and honeycomb core materials is changed, the thickness of the sandwich panels is increased in areas with high loads, and the thickness of the sandwich panels is reduced in areas with low loads, thereby achieving a reasonable distribution and arrangement of materials and maximizing material utilization.

[0039] To avoid stress concentration at local joints, a carbon fiber laminate 112 can be glued and cured at the mounting area of the battery module 200. The lower body of the battery box is structurally reinforced by gluing and curing the carbon fiber laminate 112 at the mounting area of the battery module 200, which can avoid stress concentration at local joints and improve the structural reliability of the battery box.

[0040] In this embodiment, a plurality of Type II threaded inserts 113 are pre-embedded in the mounting portion of the battery module 200 for connection to the battery module 200. The Type II threaded inserts 113 include a resin-short carbon fiber composite material layer and a wire screw insert. The wire screw insert and the resin-short carbon fiber composite material layer are fixedly disposed in the blind hole region. The resin-short carbon fiber composite material layer defines an internal threaded hole, and the wire screw insert is fixedly mounted in the internal threaded hole.

[0041] The pre-embedded Type II threaded insert 113 is similar to the pre-embedded Type I threaded insert 111 described above, except that the Type II threaded insert 113 is provided with a blind hole mounting hole region corresponding to the battery module 200 mounting portion of the base plate 110. The blind hole mounting hole region penetrates the carbon fiber upper panel, the upper adhesive film, and a portion of the honeycomb core (without penetrating). The blind hole mounting hole region also does not involve the lower adhesive film and the carbon fiber lower panel. Using similar technology, a wire screw insert (generally of a different size than that of the Type I threaded insert 111) is fixedly mounted within the blind hole mounting hole region through a resin-short carbon fiber composite material layer, completing the pre-embedding of the Type II threaded insert 113 for use in the installation of the battery module 200.

[0042] A type II threaded insert 113 is embedded in the base plate 110 to fix the battery module 200. The embedded part is embedded in the sandwich structure and does not require secondary assembly processing, thereby reducing process costs. Since the connecting embedded part is embedded in the panel, the integrity of the outer wall of the battery box is maintained, so that the battery box can easily achieve the IP67 waterproof standard.

[0043] As well as Figure 1 As shown, the position and number of the type II threaded inserts 113 can be adjusted according to the design of different battery modules 200. The exemplary solution given in this embodiment is a battery box design for installing four battery modules 200. Taking into account the installation area of the chip, the pre-embedded positions of the two groups of type II threaded inserts 113 corresponding to one battery module 200 are different from the pre-embedded positions of the type II threaded inserts 113 corresponding to the other three battery modules 200, which is not limited here.

[0044] In summary, the embodiment of the present application provides a composite sandwich panel battery box lower box, which is realized by a composite material sandwich panel battery box lower box using a composite material panel with a honeycomb sandwich core of carbon fiber composite material panels. The sandwich structure is composed of five parts: an upper panel, a bonding layer between the upper panel and the core material, a core material, a bonding layer between the lower panel and the core material, and a lower panel (i.e., a carbon fiber upper panel, an upper adhesive film, a honeycomb core, a lower adhesive film, and a carbon fiber lower panel). The upper and lower panels are made of molded carbon fiber, and the interlayer is made of a low-density aluminum honeycomb core. Applying composite materials to battery boxes can give full play to the molding advantages of composite materials. The molding is simple and some structures that are difficult to achieve with traditional machining processes can be made. By utilizing the composite material curing molding process, the battery box can be integrally molded, the number of components and the connection structure can be reduced, the reliability of the battery box structure can be improved, and the weight of the battery box can be reduced to a certain extent. The sandwich structure withstands extrusion and tension by moving the high-strength, high-modulus carbon fiber panels away from the neutral axis position. The lightweight aluminum honeycomb sandwich separates the panels from each other, thereby improving the bending stiffness of the panels. By embedding threaded inserts in the panel to connect to the battery module 200 (i.e., a battery module 200 mounting portion is provided on the bottom plate 110, and a number of Type II threaded inserts 113 are pre-embedded for connection to the battery module 200), the processing technology can be greatly simplified while ensuring the connection strength, reducing processing costs. The battery box adopts this composite material structure design to greatly reduce the weight of the battery box. At the same time, the carbon fiber panel has good flame retardancy, which can greatly improve the safety performance of the battery box. Several Type I threaded inserts 111 are pre-embedded around the bottom plate 110 for connection to the vehicle chassis, which can enhance the connection strength of the inserts, reduce weight, and reduce process costs.

[0045] This solution glues and cures carbon fiber laminates 112 at the battery module 200 mounting area to strengthen the structure, avoid stress concentration at local joints, and improve the structural reliability of the battery box. The area where the battery module 200 mounting area is located is distributed along the edge of the internal area enclosed by the side panels 120 and the bottom panel 110. The area where the battery module 200 mounting area is located forms the battery module 200 placement area. The thickness of the bottom panel 110 in the area where the battery module 200 mounting area is located is greater than the thickness in the area where the battery module 200 is placed. By changing the proportion of local composite materials and honeycomb core materials, the thickness of the sandwich panel is increased in areas with high load and reduced in areas with low load, thereby achieving a reasonable distribution and arrangement of materials and maximizing material utilization. By using carbon fiber laminates 112 (such as the upper and lower panels of the bottom panel 110, the side panels 120, and the carbon fiber laminates 112 glued and cured at the battery module 200 mounting area) as the battery box body panels, the flame retardancy of carbon fiber materials can be utilized to reduce the phenomenon of battery box heating and fire, and improve the safety of battery box use.

[0046] The above description is merely an embodiment of the present application and is not intended to limit the scope of protection of the present application. For those skilled in the art, various modifications and variations of the present application are possible. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A composite sandwich panel battery box lower box, characterized in that: Including bottom plate and side plate, The bottom plate includes a carbon fiber upper panel, an upper adhesive film, a honeycomb core, a lower adhesive film, and a carbon fiber lower panel laminated in sequence, and a plurality of I-type threaded inserts are pre-embedded around the bottom plate for connection with the vehicle chassis. The bottom plate is provided with a battery module mounting portion, which is pre-embedded with a plurality of II-type threaded inserts for connection with the battery module; The side panels in multiple directions are surrounded and fixedly connected to the bottom panel to form a lower box body of the composite sandwich panel battery box.

2. The lower box of the composite sandwich panel battery box according to claim 1, characterized in that: The thickness of the carbon fiber upper panel and the carbon fiber lower panel is 1-3 mm.

3. The lower box of the composite sandwich panel battery box according to claim 1, characterized in that: The honeycomb core is made of aluminum alloy honeycomb material with a thickness of 15-25mm.

4. The lower box of the composite sandwich panel battery box according to claim 1, characterized in that: The side panels are made of composite material with a thickness of 3-5mm.

5. The lower box of the composite sandwich panel battery box according to claim 1, characterized in that: A through-hole type mounting hole area is opened around the base plate, and the I-type threaded insert includes a resin-short carbon fiber composite material layer and a wire screw sleeve. The wire screw sleeve and the resin-short carbon fiber composite material layer are fixedly arranged in the through-hole type mounting hole area. The resin-short carbon fiber composite material layer has an internal threaded through hole, and the wire screw sleeve is fixedly installed in the internal threaded through hole.

6. The lower box of the composite sandwich panel battery box according to claim 1, characterized in that: A blind hole type mounting hole area is opened in the battery module mounting portion, and the Type II threaded insert includes a resin-short carbon fiber composite material layer and a wire screw sleeve. The wire screw sleeve and the resin-short carbon fiber composite material layer are fixedly arranged in the blind hole type mounting hole area, and an internal threaded hole is opened in the resin-short carbon fiber composite material layer, and the wire screw sleeve is fixedly installed in the internal threaded hole.

7. The lower box of the composite sandwich panel battery box according to claim 1, characterized in that: The battery module installation part is glued and cured with carbon fiber laminate.

8. The lower box of the composite sandwich panel battery box according to claim 1, characterized in that: The area where the battery module mounting portion is located is distributed along the edge of the internal area enclosed by the side panel and the bottom plate, and the battery module placement area is formed by the area where the battery module mounting portion is located. The thickness of the bottom plate in the area where the battery module mounting portion is located is greater than the thickness in the battery module placement area.

9. The lower box of the composite sandwich panel battery box according to claim 1, characterized in that: The carbon fiber upper panel of the base plate is integrally molded with the side panels in multiple directions.

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