Multi-sealing composite case structure and battery pack

Abstract

Disclosed in the present application are a multi-sealing composite case body structure, comprising: a case body frame, which comprises an edge beam profile; a bottom protective plate layer, which is assembled and connected to the case body frame, the face of the case body frame assembled to the bottom protective plate layer being an assembly face; a liquid cooling plate layer, which is located between the case body frame and the bottom protective plate layer; a buffer layer, which is sandwiched between the bottom protective plate layer and the liquid cooling plate layer; at least two first edge sealing layers, which are connected between the case body frame and the edge of the liquid cooling plate layer in a sealing manner; and at least one second edge sealing layer, which is connected between the edge of the liquid cooling plate layer and the edge of the bottom protective plate layer in a sealing manner.

Description

A multi-sealed composite box structure and battery pack

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on December 8, 2023 with application number 202323353671X and the Chinese patent application filed with the China Patent Office on December 8, 2023 with application number 2023116850823. The entire contents of the above applications are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of battery technology, and in particular to a multi-sealed composite box structure and a battery pack. Background Art

[0003] The battery box in related technologies is mostly sealed by welding, and the bottom guard plate is composed of multiple metal plates spliced ​​and welded together. Specifically, the bottom guard plate is stir-friction welded to the outside of the frame and CMT welded inside. Under high-intensity working conditions of the vehicle, the battery pack may be twisted, causing weld cracks, resulting in airtight failure and causing safety accidents. Technical issues

[0004] This application aims to solve the following technical problems: how to improve the effectiveness and durability of the battery box sealing, reduce the friction between the bottom guard plate layer and the box frame, and increase the protection effect of the battery pack liquid cooling plate and battery cells during driving. Technical Solutions

[0005] In the first aspect, the present application provides a multi-sealed composite box structure, comprising: a box frame, the box frame including a side beam profile; a bottom guard plate layer, the bottom guard plate layer is assembled and connected to the box frame, and the side of the box frame and the bottom guard plate layer assembled is an assembly surface; a liquid cooling plate layer, the liquid cooling plate layer is located between the box frame and the bottom guard plate layer; a buffer layer, the buffer layer is sandwiched between the bottom guard plate layer and the liquid cooling plate layer; at least two layers of first edge sealing layers, the first edge sealing layers are sealed between the box frame and the edge of the liquid cooling plate layer; at least one layer of second edge sealing layer, the second edge sealing layer is sealed between the edge of the liquid cooling plate layer and the edge of the bottom guard plate layer.

[0006] In a second aspect, the present application provides a battery pack comprising a battery module and a multi-sealed composite box structure. Beneficial effects

[0007] 1. By setting at least one layer of sealing at the edge where the box frame 1 and the bottom guard plate layer 3 are assembled, and setting at least two layers of sealing at the edge where the box frame 1 and the liquid cooling plate layer 2 are assembled, at least three layers of sealing are achieved, which greatly improves the airtight reliability of the battery pack. At the same time, the at least two layers of sealing between the box frame 1 and the liquid cooling plate layer 2 are arranged horizontally at intervals, and there will be no stacking effect of the sealing layer height. Therefore, the longitudinal space of the sealing is reduced compared with the battery pack with the same number of sealing layers.

[0008] 2. By setting a buffer layer between the bottom guard plate layer and the liquid cooling plate layer, the liquid cooling plate can be protected from the impact of vibration amplitude during driving, achieving its own flexible buffering and greatly reducing the problem of extrusion deformation or breakage of the liquid cooling plate.

[0009] 3. The buffer layer combined with at least two sealing layers can achieve a flexible connection for the entire battery pack. Compared with the rigid connection of welding in the existing technology, it further enhances the protection effect of the liquid cooling plate and battery cells, thereby greatly improving the safety of the battery pack.

[0010] 4. Greatly improve the protection effect of the battery pack, with good self-buffering and adjustment capabilities, further enhance the anti-fall and shockproof properties, and at the same time have good sealing, increasing the safety and reliability of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG1 is a schematic diagram of the three-dimensional structure of an embodiment of the present application;

[0012] FIG2 is a schematic diagram of a partial explosion structure of an embodiment of the present application;

[0013] Figure 3 is an enlarged view of area A in Figure 2;

[0014] FIG4 is a schematic diagram of a partial cross-sectional structure in the Z-axis direction of an embodiment of the present application;

[0015] FIG5 is a schematic diagram of the disassembled structure of an embodiment of the present application;

[0016] FIG6 is a schematic diagram of the assembly surface structure of the box frame according to an embodiment of the present application;

[0017] FIG7 is a schematic diagram of a partial explosion structure of an embodiment of the present application;

[0018] Figure 8 is an enlarged view of area B in Figure 7;

[0019] FIG9 is a schematic diagram of a buffer layer installation structure according to an embodiment of the present application;

[0020] FIG10 is a schematic diagram of the disassembled structure of the bottom guard plate layer according to an embodiment of the present application;

[0021] FIG11 is a schematic diagram of a partial cross-sectional structure of a side beam profile according to an embodiment of the present application.

[0022] Among them, the meanings of the figure marks are as follows: 1. Box frame; 11. Assembly surface; 12. Connection surface; 13. Side beam profile; 131. First step surface; 132. Second step surface; 133. Third step surface; 14. Middle beam structure; 2. Liquid cooling plate layer; 3. Bottom guard plate layer; 31. Bottom guard plate body; 311. Boss; 312. Assembly table; 313. Groove; 314. Accommodation cavity; 32. Protective coating; 321. Notch; 4. Buffer layer; 41. Through hole; 5. First edge sealing layer; 51. First sealing layer; 52. Second sealing layer; 6. Second edge sealing layer; 7. Rivet nut; 8. Bolt; 9. FDS nail; 10. Reinforcement structure; 101. Reinforcement rib; 102. Assembly boss. Modes for Carrying Out the Invention

[0023] In one embodiment, the assembly surface of the side beam profile is provided with at least one descending stepped structure from the outer edge to the inner edge, at least two first edge sealing layers are spaced apart along the descending direction of the stepped structure, and the thickness of the first edge sealing layer of the assembly surface close to the inner edge is greater than the thickness of the first edge sealing layer close to the outer edge.

[0024] By adopting the above solution, a buffer layer is provided between the bottom guard plate layer and the liquid cooling plate layer, which can increase the flexible buffering of the liquid cooling plate, and at the same time form a multi-layer seal between the box frame, the bottom guard plate layer and the liquid cooling plate layer, thereby increasing the airtight reliability of the battery pack. At least two first edge sealing layers between the box frame and the liquid cooling plate layer are arranged horizontally, which increases the number of sealing layers but does not increase the sealing thickness between the box frame and the liquid cooling plate layer. Therefore, the longitudinal space of the battery pack is reduced while improving the sealing performance.

[0025] In one embodiment, the stepped structure includes a first step surface, a second step surface and a third step surface in sequence along the descending direction, and the first edge sealing layer is provided on the first step surface and / or the second step surface.

[0026] By adopting the above solution, the air tightness of the connection between the liquid cooling plate layer and the box frame can be improved, and each first edge sealing layer is not stacked, so the total sealing thickness will not be increased.

[0027] In one embodiment, the first edge sealing layer includes a first sealing layer, one surface of the first sealing layer is bonded along the first step surface, and the other surface of the first sealing layer is bonded to the liquid cooling plate layer.

[0028] By adopting the above solution, the first layer of sealing structure is achieved to ensure good air tightness of the battery pack.

[0029] In one embodiment, the first edge sealing layer includes a second sealing layer, one side of the second sealing layer is bonded along the second step surface, and the other side of the second sealing layer is bonded to the liquid cooling plate layer.

[0030] By adopting the above solution, the second sealing layer can improve the air tightness while increasing the flexible buffering effect between the high liquid cooling plate layer and the box frame.

[0031] In one embodiment, the bottom guard plate layer includes a bottom guard plate body and a protective coating, and the protective coating is assembled and connected to a side of the bottom guard plate body away from the box frame.

[0032] By adopting the above scheme, the protective coating has the characteristics of being waterproof, flame retardant, mildew-proof, cold-proof, corrosion-resistant, aging-resistant, UV-resistant, easy to clean, high-temperature-resistant, and having good thermal insulation. It can effectively protect the bottom guard plate layer and reduce the damage to the battery caused by scratches on the car chassis. At the same time, it can play a waterproof and mildew-proof effect when water enters the car chassis.

[0033] In one embodiment, the edge of the bottom guard plate body is provided with a boss protruding toward the box frame, one side of the second edge sealing layer is bonded along the surface of the boss, and the other side of the second edge sealing layer is bonded to the liquid cooling plate layer.

[0034] By adopting the above solution, the boss is conducive to the assembly between the bottom guard plate layer and the liquid cooling plate layer, achieving the effect of edge fitting, and at the same time provides a basis for edge sealing.

[0035] In one embodiment, an accommodating cavity is formed on the inner side of the boss of the bottom guard plate body, which is recessed away from the box frame. The buffer layer is located in the accommodating cavity. The edge of the outer side of the boss extends outward to form a number of staggered assembly platforms and grooves. The assembly platforms are aligned with the bosses, and the grooves are aligned with the bottom guard plate body on the inner side of the bosses.

[0036] By adopting the above solution, it is convenient to assemble the assembly platform and the box frame, and at the same time, the buffer layer is compressed to achieve sealing and buffering effects.

[0037] In one embodiment, the accommodating cavity of the bottom guard plate body is provided with a reinforcement structure, the reinforcement structure abuts against the buffer layer, and / or the reinforcement structure passes through the buffer layer and approaches the liquid cooling plate layer.

[0038] By adopting the above solution, the reinforcement structure can improve the strength of the bottom guard plate body itself, and / or improve the assembly strength between the bottom guard plate body, the liquid cooling plate layer and the frame assembly.

[0039] In one embodiment, a surface of the buffer layer close to the liquid cooling plate layer protrudes from the plane where the boss is located.

[0040] By adopting the above solution, the buffer layer can achieve a buffering effect in its own thickness direction.

[0041] In one embodiment, the protective coating is in contact with the surface of the bottom guard plate body in a direction away from the box frame, and the protective coating is provided with a notch at the assembly platform of the bottom guard plate body.

[0042] By adopting the above solution, the notch can be designed to reduce the weight of the part of the bottom guard plate body that is not easily damaged, thereby reducing the overall weight of the battery pack and realizing the lightweight concept.

[0043] In one embodiment, a plurality of rivet nuts are arranged at intervals on the assembly surface of the box frame, the bottom guard plate layer is fastened to the rivet nuts by bolts, the liquid cooling plate layer is provided with clearance holes for accommodating the bolts, and the liquid cooling plate layer is connected to the box frame by FDS nails.

[0044] In one embodiment, the FDS perforation spacing between the liquid cooling plate layer and the box frame does not exceed 85 mm; and / or the puncture thickness of the FDS nails between the liquid cooling plate layer and the box frame does not exceed 4.5 mm; and / or the rivet nut spacing on the assembly surface does not exceed 85 mm.

[0045] By adopting the above solution, the locking stability between the liquid cooling plate layer and the box frame, as well as the locking stability between the box frame and the bottom guard plate layer can be met. At the same time, the FDS puncture thickness between the liquid cooling plate layer and the box frame does not exceed 4.5mm, which can limit the thickness and height of the box frame. In addition, the FDS puncture can achieve a flexible compression effect on the first edge sealing layer. The height of the multiple layers of the first edge sealing layer after compression is consistent, achieving space saving in the height direction, thereby achieving the effect of reducing the overall height of the battery pack.

[0046] The present application, referring to Figures 1 to 11, discloses a composite box structure with multiple seals, including a box frame 1, a liquid cooling plate layer 2, a buffer layer 4, and a bottom guard plate layer 3 arranged in sequence from top to bottom. At least two layers of first edge sealing layers 5 are arranged between the edges of the box frame 1 and the liquid cooling plate layer 2, and at least one layer of second edge sealing layer 6 is arranged between the edges of the liquid cooling plate layer 2 and the edges of the bottom guard plate layer 3. The box frame 1 has an assembly surface 11, and a plurality of rivet screws are arranged at intervals on the assembly surface 11. Mother 7, the bottom guard plate layer 3 is locked on the rivet nut 7 by bolts 8, the liquid cooling plate layer 2 is provided with a clearance hole for avoiding the bolts 8, and the liquid cooling plate layer 2 is connected to the box frame 1 through the FDS process. By adopting the above-mentioned assembly method and at least two-layer sealing structure, and providing a buffer layer 4 between the bottom guard plate layer 3 and the liquid cooling plate layer 2, the flexible buffering of the liquid cooling plate can be increased, and at the same time, a multi-layer seal is formed between the box frame 1, the bottom guard plate layer 3 and the liquid cooling plate layer 2, thereby increasing the airtight reliability of the battery pack.

[0047] The height direction of the battery pack is set as the Z axis, the direction of the battery pack toward the front end of the car when placed is the X axis, and the direction perpendicular to the X axis is the Y axis. The box frame 1 includes a frame body and an intermediate beam structure 14. The side beam body is formed by splicing multiple side beam profiles 13 end to end. The joints between the frame body and the intermediate beam structure 14 and the joints between the side beam profiles 13 and the side beam profiles 13 include but are not limited to welding, bonding or integral connection. The intermediate beam structure 14 can connect two oppositely arranged side beam profiles 13, or two parallel intermediate beam structures 14, or an intermediate beam structure 14 and a variable profile parallel to the intermediate beam structure 14. The number of specific intermediate beam structures 14 is not specifically limited.

[0048] Specifically, in this embodiment 1, 2-4 intermediate beam structures 14 are provided along the Y-axis direction, a micro beam in the X-axis direction is provided between the two intermediate beam structures 14 in the middle, the bottom surface of the intermediate beam structure 14 in the Y-axis direction, that is, the assembly surface 11 is provided with rivet nuts 7 assembled with the bottom guard plate and several FDS through-holes assembled with the bottom guard plate, the bottom surface of the side beam profile 13, that is, the assembly surface 11 is provided with FDS through-holes and through-holes for the bolts 8 to pass through, and the FDS through-holes and the bolts 8 are staggered to realize the assembly connection of the box frame 1.

[0049] In the Z-axis direction, the box frame 1 includes an assembly surface 11 located at the bottom and a connection surface 12 located at the top, the assembly surface 11 is used to assemble with the liquid cooling plate layer 2 and the bottom guard plate layer 3, and the connection surface 12 is used to connect the cover structure of the battery pack, and the assembly surface 11 of the side beam profile 13 is provided with at least one descending stepped structure from the outer edge to the inner edge, which is used to horizontally lay at least two layers of the first edge sealing layer 5, and the thickness of the first edge sealing layer 5 near the inner edge of the assembly surface 11 is greater than the thickness of the first edge sealing layer 5 near the outer edge. At least two first edge sealing layers 5 between the frame 1 and the liquid-cooling plate layer 2 are arranged horizontally, which increases the number of sealing layers but does not increase the sealing thickness between the box frame 1 and the liquid-cooling plate layer 2. Therefore, while improving the sealing performance, the longitudinal space of the battery pack along the Z axis is reduced. Each of the stepped structures includes a first step surface 131, a second step surface 132, and a third step surface 133 in the descending direction. The first edge sealing layer 5 is arranged on the first step surface 131 and / or the second step surface 132, which can improve the airtightness of the connection between the liquid-cooling plate layer 2 and the box frame 1. In this embodiment 1, the side beam profile 13 arranged along the Y axis is provided with a stepped structure, and the side beam profile 13 arranged along the X axis is provided with two stepped structures. The stepped structure located on the outside is used for sealing the first edge sealing layer 5, and the stepped structure located on the inside is used for assembly and locking of the bottom guard plate layer 3 and / or the liquid-cooling plate layer 2.

[0050] 1-8, the first edge sealing layer 5 is provided with two layers, namely a first sealing layer 51 and a second sealing layer 52, the first sealing layer 51 is arranged along the first step surface 131 on one side, and the other side of the first sealing layer 51 is in contact with the liquid cooling plate layer 2, thereby forming a first sealing ring structure; the second sealing layer 52 is arranged along the second step surface 132 on one side, and the other side of the second sealing layer 52 is in contact with the liquid cooling plate layer 2, thereby forming a second sealing ring structure; the second edge sealing layer 6 is provided with one layer, the edge of the bottom guard plate layer 3 is provided with a circumferential boss 311 protruding toward the box frame 1, the second edge sealing layer 6 is arranged along the surface of the boss 311 on one side, and the other side of the second edge sealing layer 6 is in contact with the liquid cooling plate layer 2, thereby forming a third sealing ring structure; the first sealing ring structure can play a role in sealing the box frame 1 and the liquid cooling plate layer 2, and the first sealing ring structure itself has a small amount of deformation ability to achieve a first layer buffering effect; the thickness of the second sealing ring structure is greater than the thickness of the first sealing ring structure, and The second sealing ring structure protrudes from the first stepped surface 131, and can form a pre-tightening force when the box frame 1 and the liquid cooling plate layer 2 are locked and connected, further improving the air tightness of the connection. At the same time, the squeezed second sealing ring structure itself still has a certain deformation ability, so it also achieves a second layer of buffering effect; the third sealing ring structure can play a role in sealing the bottom guard plate layer 3 and the liquid cooling plate layer 2. When the bolt 8 passes through the bottom guard plate layer 3, the liquid cooling plate layer 2 and the rivet nut 7 on the box frame 1 are locked, the third sealing ring structure can form a pre-tightening force, further improving the bottom guard plate layer 3. The connection between the plate layer 3 and the liquid cooling plate layer 2 is airtight, and the third sealing ring structure itself has a certain deformation ability, thereby realizing the third layer buffering effect. By adopting the three-layer buffering effect, the flexible sealing effect of the battery pack as a whole is greatly improved. While meeting its own airtightness, it has a strong self-buffering ability, which can reduce the hardness of the battery cells and the liquid cooling plate layer 2 inside the battery pack caused by the vibration of the car itself during driving, and reduce the possibility of breakage and bending of the liquid cooling plate layer 2, effectively protecting the safety of the battery cells, thereby improving the overall safety performance of the battery pack.

[0051] It should be noted that the first, second, and third sealing ring structures include, but are not limited to, sealing glue, silicone foam sealing rings, or structural adhesive. In this embodiment 1, the first sealing ring structure is coated with sealing glue to form the first sealing layer 51, and the second and third sealing ring structures are both silicone foam sealing rings, which can provide excellent cushioning and sealing properties. The first and second sealing ring structures are spaced apart in the horizontal direction so that they are not stacked, thereby not increasing the total sealing thickness and reducing the Z-axis height of the battery pack.

[0052] In some embodiments, as shown in Figures 8 and 10, in order to ensure the performance of the bottom surface of the bottom guard plate layer 3 and improve its own protection ability, the bottom guard plate layer 3 is designed to be an integrally connected or integrally assembled bottom guard plate body 31 and a protective coating 32, and the protective coating 32 is assembled on the bottom surface of the bottom plate. In this embodiment 1, the protective coating 32 adopts a PVC coating structure. The PVC coating structure has the characteristics of being waterproof, flame retardant, mildew-proof, cold-proof, corrosion-resistant, aging-resistant, UV-resistant, easy to clean, high-temperature-resistant, and having good thermal insulation. It can effectively protect the bottom guard plate layer 3, reduce the damage to the battery caused by scratches on the car chassis, and at the same time, it can play a waterproof and mildew-proof effect when water enters the car chassis.

[0053] Specifically, in this embodiment 1, as shown in Figures 9 and 10, the edge of the bottom guard plate body 31 is provided with a circumferential boss 311 protruding toward the box frame 1, and the second edge sealing layer 6 is bonded along the surface of the boss 311 on one side and bonded to the liquid cooling plate layer 2 on the other side. The boss 311 is conducive to the assembly between the bottom guard plate layer 3 and the liquid cooling plate layer 2, achieving the effect of edge bonding, and at the same time providing a basis for edge sealing; the inner side of the boss 311 of the bottom guard plate body 31 forms a receiving cavity 314 recessed away from the box frame 1, and the buffer layer 4 is located in the receiving cavity 314, and the outer edge of the boss 311 extends outward to form a plurality of staggered assembly platforms 312 and grooves 313, the assembly platforms 312 are aligned with the boss 311, and the grooves 313 are aligned with the bottom guard plate body 31 inside the boss 311, so as to facilitate the assembly of the assembly platform 312 with the box frame 1, and at the same time press the buffer layer 4 to achieve sealing and buffering effects.

[0054] Referring to Figures 4 and 9, in order to enable the buffer layer 4 located in the accommodating cavity 314 to play a buffering role, the surface of the buffer layer 4 close to the liquid cooling plate layer 2 is raised above the plane where the boss 311 is located, so that the buffer layer 4 can achieve a buffering effect in the Z-axis direction. Therefore, the thickness of the buffer layer 4 needs to be greater than the depth of the accommodating cavity 314. If the buffer layer 4 is too thick, it will increase the overall weight of the battery pack. Therefore, in some embodiments, a reinforcement structure 10 is provided in the accommodating cavity 314 of the bottom guard plate body 31. The reinforcement structure 10 abuts against the buffer layer 4, and / or the reinforcement structure 10 passes through the buffer layer 4 and approaches the liquid cooling plate layer 2. The reinforcement structure 10 can increase the strength of the bottom guard plate body 31 itself, and / or improve the assembly strength between the bottom guard plate body 31, the liquid cooling plate layer 2 and the frame assembly.

[0055] Specifically, as shown in Figures 9 and 10, the reinforcement structure 10 includes a reinforcing rib 101 and an assembly projection. The reinforcing rib 101 projects upward along the Z axis, thereby reducing the thickness of the buffer layer 4 and allowing its upper surface to be elevated above the boss 311. The reinforcing rib 101 is not limited in structure or orientation, as long as it can stably support the buffer layer 4 on a flat surface. The assembly projection also projects upward along the Z axis and is used to approach the intermediate beam structure 14 disposed along the X axis, allowing a screw to pass through the assembly projection and assemble and lock with the rivet nut 7 on the bottom surface of the intermediate beam structure 14. The height of the assembly projection must meet the height of the protruding end of the bolt 8, so that the lower end of the bolt 8 does not protrude from the bottom surface of the bottom guard plate body 31. The buffer layer 4 is provided with a through hole 41 to avoid the assembly projection. When the screw passes through the assembly projection and is assembled and locked with the rivet nut 7 on the bottom surface of the intermediate beam structure 14, it does not affect the buffer layer 4. The shape of the assembly projection is not specifically limited. In this embodiment 1, the reinforcing rib 101 is in a strip shape, and the assembly boss 102 is in a truncated cone shape.

[0056] In some embodiments, as shown in Figures 3 and 10, in order to further improve the weight balance of the battery pack, appropriate weight reduction can be performed on the protective coating 32. Specifically, the protective coating 32 is in contact with the surface of the bottom guard plate body 31 away from the box frame 1 to protect the bottom surface of the bottom guard plate. In the upward protruding portion of the bottom surface of the bottom guard plate, the bottom surfaces of the assembly boss 102 and the assembly platform 312 are farther away from other planes, so the possibility of friction or collision is relatively small. Therefore, the protective coating 32 is provided with a notch 321 at the assembly platform 312 and the assembly boss 102 of the bottom guard plate body 31, thereby reducing the area of ​​the protective coating 32, saving raw materials, and having a weight reduction effect, thereby reducing the overall weight balance of the battery pack and realizing the concept of lightweighting.

[0057] In order to ensure the locking stability between the liquid cooling plate layer 2 and the box frame 1, and the locking stability between the box frame 1 and the bottom guard plate layer 3, it is necessary to limit the spacing of the FDS perforations and / or the spacing of the rivet nuts 7. Specifically, the spacing of the FDS perforations between the liquid cooling plate layer 2 and the box frame 1 does not exceed 85 mm; and / or the spacing of the rivet nuts 7 on the assembly surface 11 does not exceed 85 mm, and / or the puncture thickness of the FDS nails 9 between the liquid cooling plate layer 2 and the box frame 1 does not exceed 4.5 mm, and the puncture thickness of the FDS nails 9 between the liquid cooling plate layer 2 and the box frame 1 does not exceed 4.5 mm. The thickness and height of the box frame 1 can be limited to achieve a spatial compression effect on the first edge sealing layer 5 and the second edge sealing layer 6 in the Z-axis direction, thereby achieving a flexible connection and space reduction effect. And within the specified range, the spacing of each of the rivet nuts 7 can be inconsistent or partially consistent; the spacing of each FDS perforation can be inconsistent or partially consistent, and can be designed according to actual conditions to achieve a staggered arrangement between the rivet nuts 7 and the FDS perforations.

[0058] The present application also relates to a battery pack, comprising a cover, a battery module and a composite box structure with multiple seals. The cover is assembled and connected to the connecting surface 12 of the box frame 1, and the battery module is limitedly assembled in the box frame 1 below the cover. The three-layer flexible sealing structure between the box frame 1, the bottom guard plate layer 3 and the liquid cooling plate layer 2 can be used to improve the resistance of the battery cells in the battery module, thereby greatly improving the protective effect of the battery pack, having good self-buffering and adjustment capabilities, and further enhancing the anti-fall and shockproof characteristics. At the same time, it has good sealing, increasing the safety and reliability of the battery pack.

[0059] In summary, the multi-sealed composite box structure and battery pack provided by this application have the following technical effects:

[0060] 1. By providing at least one layer of sealing at the edge where the box frame 1 and the bottom guard plate layer 3 are assembled, and at least two layers of sealing at the edge where the box frame 1 and the liquid cooling plate layer 2 are assembled, at least three layers of sealing are achieved, greatly improving the airtight reliability of the battery pack. At the same time, the at least two layers of sealing between the box frame 1 and the liquid cooling plate layer 2 are arranged horizontally at intervals, eliminating the stacking effect of the sealing layers. Therefore, the longitudinal space required for sealing is reduced compared to battery packs with the same number of sealing layers.

[0061] 2. By providing a buffer layer 4 between the bottom guard plate layer 3 and the liquid cooling plate layer 2, the liquid cooling plate can be protected from vibration during driving, achieving its own flexible buffering, greatly reducing the problem of extrusion deformation or fracture of the liquid cooling plate;

[0062] 3. The buffer layer 4, in combination with at least two sealing layers, can achieve a flexible connection for the entire battery pack. Compared with the rigid connection of welding in the prior art, it further enhances the protection effect of the liquid cooling plate and the battery cell, thereby greatly improving the safety of the battery pack.

Claims

1. A multi-sealed composite box structure, comprising: A box frame (1), the box frame (1) comprising a side beam profile (13); A bottom guard plate layer (3), wherein the bottom guard plate layer (3) is assembled and connected to the box frame (1), and a side where the box frame (1) and the bottom guard plate layer (3) are assembled is an assembly surface (11); A liquid cooling plate layer (2), the liquid cooling plate layer (2) being located between the box frame (1) and the bottom protective plate layer (3); A buffer layer (4), the buffer layer (4) being sandwiched between the bottom guard plate layer (3) and the liquid cooling plate layer (2); At least two first edge sealing layers (5), wherein the first edge sealing layers (5) are sealed between the edges of the box frame (1) and the liquid cooling plate layer (2); At least one second edge sealing layer (6), wherein the second edge sealing layer (6) is sealed between the edge of the liquid cooling plate layer (2) and the edge of the bottom protective plate layer (3).

2. A multi-sealed composite box structure according to claim 1, wherein: The assembly surface (11) of the side beam profile (13) is provided with at least one descending step-like structure from the outer edge to the inner edge, at least two of the first edge sealing layers (5) are arranged at intervals along the descending direction of the step-like structure, and the thickness of the first edge sealing layer (5) near the inner edge of the assembly surface (11) is greater than the thickness of the first edge sealing layer (5) near the outer edge.

3. A multi-sealed composite box structure according to claim 2, wherein: The stepped structure comprises a first step surface (131), a second step surface (132) and a third step surface (133) in sequence along the descending direction, and the first edge sealing layer (5) is arranged on the first step surface (131) and / or the second step surface (132).

4. A multi-sealed composite box structure according to claim 3, wherein: The first edge sealing layer (5) comprises a first sealing layer (51), one side of the first sealing layer (51) is bonded along the first step surface (131), and the other side of the first sealing layer (51) is bonded to the liquid cooling plate layer (2).

5. A multi-sealed composite box structure according to claim 4, wherein: The first edge sealing layer (5) comprises a second sealing layer (52), one side of the second sealing layer (52) is bonded along the second step surface (132), and the other side of the second sealing layer (52) is bonded to the liquid cooling plate layer (2).

6. A multi-sealed composite box structure according to claim 5, wherein: The bottom guard plate layer (3) comprises a bottom guard plate body (31) and a protective coating (32), wherein the protective coating (32) is assembled and connected to a side of the bottom guard plate body (31) away from the box frame (1).

7. A multi-sealed composite box structure according to claim 6, wherein: The edge of the bottom guard plate body (31) is provided with a circumferential boss (311) protruding in the direction of the box frame (1); one side of the second edge sealing layer (6) is bonded along the surface of the boss (311); and the other side of the second edge sealing layer (6) is bonded to the liquid cooling plate layer (2).

8. A multi-sealed composite box structure according to claim 6, wherein: The inner side of the boss (311) of the bottom guard plate body (31) forms a receiving cavity (314) which is recessed in a direction away from the box frame (1); the buffer layer (4) is located in the receiving cavity (314); the outer edge of the boss (311) extends outward to form a plurality of staggered assembly platforms (312) and grooves (313); the assembly platforms (312) are aligned with the boss (311); and the grooves (313) are aligned with the bottom guard plate body (31) on the inner side of the boss (311).

9. A multi-sealed composite box structure according to claim 8, wherein: The accommodating cavity (314) of the bottom guard plate body (31) is provided with a reinforcing structure (10), the reinforcing structure (10) is in contact with the buffer layer (4), and / or the reinforcing structure (10) passes through the buffer layer (4) and approaches the liquid cooling plate layer (2).

10. A multi-sealed composite box structure according to claim 8 or 9, wherein: The surface of the buffer layer (4) close to the liquid cooling plate layer (2) protrudes from the plane where the boss (311) is located.

11. A multi-sealed composite box structure according to claim 6, wherein: The protective coating (32) is in contact with the surface of the bottom guard plate body (31) in a direction away from the box frame (1), and the protective coating (32) is provided with a notch (321) at the assembly platform (312) of the bottom guard plate body (31).

12. A multi-sealed composite box structure according to claim 1, wherein: The assembly surface (11) of the box frame (1) is provided with a plurality of rivet nuts (7) at intervals, the bottom guard plate layer (3) is fastened to the rivet nuts (7) by bolts (8), the liquid cooling plate layer (2) is provided with clearance holes for evading the bolts (8), and the liquid cooling plate layer (2) is connected to the box frame (1) by FDS nails (9).

13. A multi-sealed composite box structure according to claim 12, wherein: The FDS perforation spacing between the liquid cooling plate layer (2) and the box frame (1) does not exceed 85 mm; and / or the puncture thickness of the FDS nail (9) between the liquid cooling plate layer (2) and the box frame (1) does not exceed 4.5 mm; and / or the spacing between the rivet nuts (7) on the assembly surface (11) does not exceed 85 mm.

14. A battery pack, comprising a battery module and a multi-sealed composite box structure according to any one of claims 1 to 13.

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