Beam structure for battery pack, manufacturing method and battery pack

Abstract

The invention discloses a cross beam structure for a battery pack and a manufacturing method thereof.The cross beam structure comprises a core plate and a beam body, the core plate extends in the first direction and comprises a main core part, an upper edge part and a lower edge part, the plate face of the main core part is perpendicular to the second direction, and the upper edge part and the lower edge part are distributed at the upper end and the lower end of the main core part in the third direction; the first and second guide rails extend backwards along a second direction; the first direction, the second direction and the third direction are vertical in pairs; the beam body covers the core plate; the beam body and the core plate are made of different metal materials, and the material strength of the core plate is larger than that of the beam body. And a battery pack having the same. According to the beam structure, the beam body with low material strength wraps the core plate with high material strength, so that the beam structure meeting the requirements of structural strength and impact resistance can be manufactured by using fewer materials, and the requirement of lightweight design is met; meanwhile, the overall structure is relatively simple, the occupied space is small, and the installation freedom degree of the cross beam structure, other structures of the battery pack and a vehicle body can be effectively improved.

Description

Technical Field

[0001] This application relates to the technical field of battery box structures, and particularly to a crossbeam structure for a battery pack, a manufacturing method thereof, and a battery pack. Background Art

[0002] As a carrier and protection device for batteries, a battery pack not only needs to accommodate all battery cells and management systems, but also needs to meet various requirements involved in battery safety performance, such as vibration, extrusion, drop, water immersion, and fire. It can be seen that the structural advantages of the battery pack box can directly affect the safety and service life of the battery. With the continuous improvement of battery energy density, the volume and weight of the battery pack are also increasing continuously. After the size of the battery pack increases, the performance requirements such as the overall strength and stiffness of the battery pack also increase simultaneously. How to balance the weight, size, and strength performance requirements of the battery pack has become a major problem in the design and manufacture of the battery pack.

[0003] Currently, the battery packs of electric vehicles generally use steel or aluminum alloy structural boxes. Among them, the steel structural box is formed by sheet metal stamping, and the box body is relatively heavy in weight and not high in corrosion resistance; the aluminum alloy structural box is relatively light, but the comprehensive cost is high and the impact resistance is weak. And since the vehicle travels in the front-rear direction, when the vehicle moves forward or backward, the crossbeam structure of the battery pack is often prone to collision or impact. In this regard, in order to balance the performance requirements of the crossbeam structure, the common practice in related technologies is to reinforce the crossbeam in terms of structural design and material usage. Although this improves the anti-collision and safety performance of the battery pack, on the one hand, the newly added reinforcing structure and material usage increase the size and weight of the battery pack, affecting the lightweight of the whole vehicle; on the other hand, it also increases the structural complexity of the crossbeam and the installation freedom is relatively low. Summary of the Invention

[0004] In view of the above problems, the embodiments of this application provide a crossbeam structure for a battery pack, a manufacturing method thereof, and a battery pack, which can effectively improve the structural strength of the crossbeam structure while ensuring that the crossbeam has a relatively small size and a relatively simple structure.

[0005] According to one aspect of the embodiments of this application, a crossbeam structure for a battery pack is provided, including: a core plate, the core plate extends along a first direction, including a main core part, an upper edge part, and a lower edge part, the plate surface of the main core part is perpendicular to a second direction, the upper edge part and the lower edge part are distributed at the upper and lower ends of the main core part along a third direction, and respectively extend backward along the second direction; the first direction, the second direction, and the third direction are perpendicular to each other pairwise; a beam body, the beam body covers the core plate; wherein, the beam body and the core plate are made of different metal materials, and the material strength of the core plate is greater than the material strength of the beam body.

[0006] In an exemplary embodiment of the present application, the beam body includes a main beam portion, an upper beam portion, and a lower beam portion. The plate surface of the main beam portion is perpendicular to the second direction. The upper beam portion and the lower beam portion are distributed at the upper and lower ends of the main beam portion along the third direction and extend backward along the second direction respectively. Among them, the main beam portion covers the main core portion, the upper beam portion covers the upper edge portion, and the lower beam portion covers the lower edge portion.

[0007] In an exemplary embodiment of the present application, a plurality of first weight reduction holes are provided in the upper edge portion, and the plurality of first weight reduction holes are spaced along the first direction on the plate surface of the upper edge portion; and / or a plurality of second weight reduction holes are provided in the lower edge portion, and the plurality of second weight reduction holes are spaced along the first direction on the plate surface of the lower edge portion.

[0008] In an exemplary embodiment of the present application, a plurality of third weight reduction holes are provided in the main core portion, and the plurality of third weight reduction holes are spaced along the first direction on the plate surface of the main core portion; among them, at least one third weight reduction hole is configured as a mounting interface, and the mounting interface penetrates through the plate surfaces of the main beam portion and the main core portion along the second direction.

[0009] In an exemplary embodiment of the present application, the beam body further includes a reinforcing rib portion. The reinforcing rib portion is connected between the upper beam portion and the lower beam portion and is connected to the main beam portion forward along the second direction. The reinforcing rib portion includes a plurality of first reinforcing ribs and a plurality of second reinforcing ribs. The plurality of first reinforcing ribs extend along the third direction and are spaced along the first direction. The upper end of the first reinforcing rib is connected to the upper beam portion, and the lower end is connected to the lower beam portion. The plurality of second reinforcing ribs extend along the first direction and are spaced along the third direction and are cross-connected with the second reinforcing ribs.

[0010] In an exemplary embodiment of the present application, the crossbeam structure further includes a support. The front end of the support is provided with a mounting structure for externally connecting to the vehicle body. The rear end of the support is connected to the beam body, and a plurality of third reinforcing ribs are formed along the circumferential direction of the support extending along the plate surface of the main beam portion. The orthographic projection of the third reinforcing ribs in the second direction coincides with the plate surface of the main core portion.

[0011] In an exemplary embodiment of the present application, the orthographic projection of the upper beam portion in the third direction coincides with the lower beam portion; the extension length of the lower edge portion in the second direction is less than that of the upper edge portion, so that a connection area suitable for external welding is formed between the end of the lower edge portion away from the main core portion and the end of the lower beam portion away from the main beam portion.

[0012] In an exemplary embodiment of the present application, end plates integrally formed with the beam body are provided at both ends of the beam body in the first direction. The plate surface of the end plate is perpendicular to the first direction, and the end plate covers the upper beam portion upward and the lower beam portion downward in the second direction; and covers the main beam portion forward in the third direction and covers the end of the upper beam portion away from the main beam portion and the end of the lower beam portion away from the main beam portion backward respectively.

[0013] According to a second aspect of the embodiments of the present application, a battery pack is provided, which includes an upper cover, a bottom plate, a front cross beam, a rear cross beam, and two side beams. Both ends of the front cross beam are respectively cooperated with the two ends of the rear cross beam through the side beams to enclose a receiving cavity; the upper cover is disposed above the receiving cavity, and the four sides of the upper cover are respectively fixedly connected to the front cross beam, the rear cross beam, and the two side beams; the bottom plate is attached to the lower side of the receiving cavity, and the four sides of the bottom plate are respectively fixedly connected to the front cross beam, the rear cross beam, and the two side beams; wherein, at least one of the front cross beam and the rear cross beam is the above-mentioned cross beam structure.

[0014] According to a third aspect of the embodiments of the present application, a manufacturing method for the above-mentioned cross beam structure is provided. The method includes: stamping a metal material plate with relatively high material strength and relatively high melting point into a core plate; placing the core plate in a die-casting mold for positioning and fixing; wherein, a die-casting cavity of the beam body is formed between the positioned and fixed core plate and the inner surface of the die-casting mold; melting a metal material with relatively low material strength and relatively low melting point into a metal liquid; injecting the metal liquid into the die-casting mold at a preset die-casting temperature for die-casting. After the die-cast part is solidified and cooled to form, it is demolded and taken out; the die-cast part is shaped and trimmed to obtain the cross beam structure.

[0015] By using a beam body with low material strength to cover a core plate with high material strength, the cross beam structure of the present application can use less materials to produce a cross beam structure that meets the requirements of structural strength and anti-impact performance, meeting the needs of lightweight design; at the same time, without adding additional reinforcement structures outside the beam body, the safety performance of the battery pack can be ensured, the structure is relatively simple and occupies less space, and the installation freedom between the cross beam structure and other structures of the battery pack and between the battery pack and the vehicle body can be effectively improved.

[0016] The above description is only an overview of the technical solutions of the embodiments of the present application. In order to be able to understand the technical means of the embodiments of the present application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features, and advantages of the embodiments of the present application more obvious and understandable, the following specifically illustrates the specific embodiments of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0018] Figure 1 The structural schematic diagram of the cross beam structure described in the embodiments of the present application is shown;

[0019] Figure 2Shows a cross-sectional view of the crossbeam structure described in the embodiments of the present application;

[0020] Figure 3 Shows a schematic structural diagram of the core plate described in the embodiments of the present application;

[0021] Figure 4 Shows the schematic structure of the beam body described in the embodiments of the present application Figure 1 ;

[0022] Figure 5 Shows the schematic structure of the beam body described in the embodiments of the present application Figure 2 ;

[0023] Figure 6 Shows a schematic connection diagram of the support and the beam body described in the embodiments of the present application;

[0024] Figure 7 Shows a schematic connection diagram of the crossbeam structure and the upper cover and the bottom plate described in the embodiments of the present application;

[0025] Figure 8 Shows a schematic connection diagram of the crossbeam structure and the side beam described in the embodiments of the present application;

[0026] Figure 9 Shows a schematic structural diagram of the battery pack described in the embodiments of the present application;

[0027] Figure 10 Shows a schematic flow diagram of the method described in the embodiments of the present application.

[0028] Explanation of the reference numerals in the drawings:

[0029] 1 - Core plate, 11 - Main core part, 111 - Third weight reduction hole, 112 - Installation interface, 1121 - Electrical interface structure, 1122 - Explosion-proof valve interface structure, 1123 - Thermal management liquid pipeline interface structure, 1124 - Cylinder, 12 - Upper edge part, 121 - First weight reduction hole, 13 - Lower edge part, 131 - Second weight reduction hole,

[0030] 2 - Beam body, 21 - Main beam part, 22 - Upper beam part, 23 - Lower beam part, 231 - Connection area, 24 - Reinforcement part, 241 - First reinforcement, 242 - Second reinforcement, 2421 - Bracket, 25 - End plate, 251 - Chamfered corner,

[0031] 3 - Support, 31 - Mounting structure, 32 - Third reinforcement,

[0032] 100 - Crossbeam structure, 200 - Upper cover, 201 - Sealant, 202 - FDS screw, 300 - Bottom plate, 400 - Side beam, 500 - Front crossbeam,

[0033] x - The first direction, y - The second direction, z - The third direction.

[0034] The realization of the purpose of this application, functional features and advantages will be further described in combination with embodiments with reference to the accompanying drawings. Detailed implementation manners

[0035] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in various forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this application will be more complete and comprehensive, and will fully convey the concept of the example embodiments to those skilled in the art.

[0036] In addition, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of the embodiments of this application. However, those skilled in the art will realize that the technical solutions of this application can be practiced without one or more of the specific details, or other methods, components, devices, steps, etc. may be used. In other cases, well-known methods, devices, implementations, or operations are not shown or described in detail to avoid obscuring aspects of this application.

[0037] The present application will be further described in detail below in combination with the accompanying drawings and specific embodiments. It should be noted here that the technical features involved in the various embodiments of the present application described below can be combined with each other as long as they do not conflict with each other. The embodiments described below by referring to the accompanying drawings are exemplary and are intended to explain the present application, and should not be construed as limiting the present application.

[0038] It should also be noted that in the description of this application, the first direction, the second direction, and the third direction are three mutually perpendicular directions in a three-dimensional coordinate system, and the terms "front", "rear", "left", "right", "up", "down", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings; in the shown accompanying drawings, the x direction is the first direction, where the direction of the arrow is "left" and the opposite is "right"; the y direction is the second direction, where the direction of the arrow is "front" and the opposite is "rear"; the z direction is the third direction, where the direction of the arrow is "up" and the opposite is "down". The "inside" and "outside" mentioned in the embodiments of this application are defined based on the contour of the corresponding component. It can be understood that the above-mentioned terms indicating the orientation or positional relationship are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the application.

[0039] Such as Figure 1 and Figure 2As shown in the figure, this embodiment provides a crossbeam structure for a battery pack, which includes a core plate 1 and a beam body 2. The core plate 1 extends along the first direction x and includes a main core part 11, an upper edge part 12, and a lower edge part 13. The plate surface of the main core part 11 is perpendicular to the second direction y. The upper edge part 12 and the lower edge part 13 are distributed at the upper and lower ends of the main core part 11 along the third direction z and extend backward along the second direction y respectively. Among them, the first direction x, the second direction y, and the third direction z are perpendicular to each other pairwise. The beam body 2 also extends along the first direction x and covers the core plate 1. At the same time, the beam body 2 and the core plate 1 are made of different metal materials, and the material strength of the core plate 1 is greater than that of the beam body 2. In this way, by using the beam body 2 with low material strength to cover the core plate 1 with high material strength, a crossbeam structure that meets the requirements of structural strength and anti-impact performance can be made with less material, meeting the requirements of lightweight design. At the same time, the safety performance of the battery pack can be ensured without adding additional reinforcement structures outside the beam body 2. The structure is relatively simple and occupies less space, which can effectively improve the installation freedom of the crossbeam structure with other structures of the battery pack and the battery pack with the vehicle body.

[0040] For example, in this embodiment, the core plate 1 is made of high-strength steel plate, and the beam body 2 is made of aluminum alloy, and the beam body 2 can be covered on the core plate 1 by die-casting. Specifically, after the core plate 1 is placed and fixed in the die-casting mold, the molten aluminum alloy liquid is injected into the die-casting mold for die-casting, so that the molten aluminum alloy liquid fully fills and wraps the core material. After the die-casting part is solidified and formed, a crossbeam structure with the beam body 2 covering the core plate 1 is obtained. At this time, the beam body 2 is an integrally formed part. At the same time, the core plate 1 can use the main core part 11 to improve the lateral structural strength and anti-impact performance of the beam body 2, and use the upper edge part 12 and the lower edge part 13 to improve the structural strength and connection strength on the upper and lower sides of the beam body 2 respectively, so that it can meet severe working conditions such as collision, impact, and extrusion, and achieve lightweight to a certain extent.

[0041] It can be understood that in other embodiments, the core plate 1 and the beam body 2 can also be made of other metal materials, as long as the material strength of the core plate 1 is greater than that of the beam body 2. In addition, the implementation method of covering the beam body 2 on the core plate 1 can also be to design the beam body 2 as a split type and clamp it on both sides of the core plate 1, and then through welding and composite forming (such as explosion welding, friction welding, etc.), cold rolling covering or CMT (cold metal transfer welding) connection process to realize the setting that the core plate 1 is covered inside the beam body 2. The specific connection method is the prior art and will not be elaborated here.

[0042] In some embodiments, such as Figure 2As shown in the figure, the beam body 2 includes a main beam portion 21, an upper beam portion 22, and a lower beam portion 23. The plate surface of the main beam portion 21 is perpendicular to the second direction y. The upper beam portion 22 and the lower beam portion 23 are distributed at the upper and lower ends of the main beam portion 21 along the third direction z and extend backward along the second direction y respectively. Among them, the main beam portion 21 covers the main core portion 11, the upper beam portion 22 covers the upper edge portion 12, and the lower beam portion 23 covers the lower edge portion 13. In this way, the shape of the beam body 2 can be further fixed, so that the overall force-bearing structure of the beam body 2 is the same as or consistent with the overall force-bearing structure of the core plate 1. Furthermore, the load / force received by the beam body 2 is transmitted and shared between the core plate 1 and the beam body 2 through an effective and continuous transmission path.

[0043] In some embodiments, as Figure 2 and Figure 3 shown in the figure, a plurality of first weight-reducing holes 121 are provided in the upper edge portion 12, and the plurality of first weight-reducing holes 121 are spaced along the first direction x on the plate surface of the upper edge portion 12; and / or a plurality of second weight-reducing holes 131 are provided in the lower edge portion 13, and the plurality of second weight-reducing holes 131 are spaced along the first direction x on the plate surface of the lower edge portion 13. In this way, the weight of the core plate 1 can be further reduced, and the light weight of the crossbeam structure can be ensured.

[0044] It can be understood that the first weight-reducing holes 121 and / or the second weight-reducing holes 131 can be blind holes provided along the third direction z, or through holes provided through along the third direction z. Preferably, they are through holes. In this way, the beam body parts constituting the upper beam portion 22 on the upper and lower sides of the upper edge portion 12 can be connected together through the first weight-reducing holes 121, and the beam body parts constituting the lower beam portion 23 on the upper and lower sides of the lower edge portion 13 can be connected together through the second weight-reducing holes 131, thereby further improving the connection stability between the core plate 1 and the beam body 2. At the same time, when the beam body 2 is covered on the core plate 1 by die-casting, the through design of the first weight-reducing holes 121 and / or the second weight-reducing holes 131 can act as a runner, enabling the molten aluminum alloy liquid to pass through it, guiding the flow direction of the molten liquid during die-casting, improving the filling uniformity of the thick and distal parts, effectively reducing the generation of defects such as air holes and shrinkage holes, and ensuring the structural strength and stiffness performance of the beam body 2.

[0045] In some embodiments, as Figure 4 and Figure 5As shown, a plurality of third weight-reducing holes 111 are formed in the main core part 11, and the plurality of third weight-reducing holes 111 are distributed at intervals along the first direction x on the plate surface of the main core part 11; in this way, the weight of the core plate 1 can be further reduced to ensure the light weight of the crossbeam structure 100; wherein, at least one third weight-reducing hole 111 is configured as an installation interface 112, and the installation interface 112 penetrates through the plate surfaces of the main beam part 21 and the main core part 11 along the second direction y and is configured as a corresponding interface structure according to specific functions. For example, an electrical interface structure 1121 provided on the left side of the main beam part 21 can meet the installation of charging terminals; an explosion-proof valve interface structure 1122 provided in the middle of the main beam part 21 can meet the installation of explosion-proof valves; a thermal management liquid pipeline interface structure 1123 provided on the right side of the main beam part 21 can meet the installation and sealing of coolant pipeline joints. In this way, through the arrangement of the installation interface 112, the installation of corresponding functional devices can be realized, and the number and structural form of the installation interface 112 can be selected and set according to specific functional requirements, which are not limited here and will not be elaborated further.

[0046] It can be understood that the third weight-reducing hole 111 can be a blind hole provided along the second direction y or a through hole provided through along the second direction y. Preferably, it is a through hole. In this way, the beam parts constituting the main beam part 21 on the front and back sides of the main core part 11 can be connected together through the third weight-reducing hole 111, thereby further improving the connection stability between the core plate 1 and the beam body 2. At the same time, when the beam body 2 is coated on the core plate 1 by die-casting, the through design of the third weight-reducing hole 111 can also play the role of a runner, which is the same as the function of the above-mentioned first weight-reducing hole 121 or second weight-reducing hole 131, and will not be elaborated here.

[0047] In some embodiments, such as Figure 2 and Figure 4As shown, the beam body 2 further includes a reinforcing rib portion 24. The reinforcing rib portion 24 is connected between the upper beam portion 22 and the lower beam portion 23 and is connected to the main beam portion 21 forward along the second direction y. The reinforcing rib portion 24 includes a plurality of first reinforcing ribs 241 and a plurality of second reinforcing ribs 242. The plurality of first reinforcing ribs 241 extend along the third direction z and are arranged at intervals along the first direction x. The upper ends of the first reinforcing ribs 241 are connected to the upper beam portion 22, and the lower ends of the first reinforcing ribs 241 are connected to the lower beam portion 23. In this way, on the one hand, the first reinforcing ribs 241 can provide support between the upper beam portion 22 and the lower beam portion 23, realize the force transmission between the upper beam portion 22 and the lower beam portion 23 in the third direction z, and improve the bearing capacity of the cross beam structure 100 in the third direction z. On the other hand, the upper beam portion 22 and the lower beam portion 23 at the rear end in the second direction y can be connected to the main beam portion 21, improving the structural strength of the main beam portion 21 in the second direction y. At the same time, the plurality of second reinforcing ribs 242 extend along the first direction x and are arranged at intervals along the third direction z and are cross-connected with the second reinforcing ribs 242. The second reinforcing ribs 242 can connect the plurality of first reinforcing ribs 241 into one body, thereby improving the structural strength of the reinforcing rib portion 24.

[0048] It can be understood that the corresponding interface structure of the aforementioned installation interface 112 can be a column 1124 designed on the rear side of the main beam portion 21 to meet the installation of threaded fasteners. The column extends backward along the second direction y and provides a threaded installation point after being processed and tapped. At the same time, the column can be arranged close to the reinforcing rib portion 24 to improve its bending and shear resistance performance and can perform torque transmission with the reinforcing rib portion 24 to ensure the structural strength and connection stability of the column.

[0049] Optionally, as Figure 3 shown, the second reinforcing rib 242 arranged lower in the third direction z can be integrally provided with a bracket 2421 to meet the fixation of functional components such as battery cable copper bars and liquid cooling plates inside the battery pack.

[0050] In some embodiments, as Figure 5 and Figure 6 shown, the cross beam structure 100 further includes a support 3. The front end of the support 3 is provided with a mounting structure 31 for externally connecting to the vehicle body. The rear end of the support 3 is connected to the beam body 2, and a plurality of third reinforcing ribs 32 are formed along the circumferential direction at the rear end of the support 3 and extend along the plate surface of the main beam portion 21. The positive projection of the third reinforcing ribs 32 in the second direction y coincides with the plate surface of the main core portion 11. In this way, the force of the support 3 can be transmitted to the core plate 1, further improving the connection stability between the support 3 and the beam body 2 and having a better force-bearing effect.

[0051] It can be understood that the above-mentioned mounting structure 31 can be to set mounting holes at the front end part of the support 3 and correspondingly install steel riveting bushings to be used as the mounting points for connecting the battery pack to the vehicle body. This is a common connection structure in related technologies and will not be elaborated here.

[0052] In some embodiments, as Figure 7 shown, the positive projection of the upper beam part 22 of the beam body 2 in the third direction z coincides with the lower beam part 23, that is, the upper beam part 22 and the lower beam part 23 of the beam body 2 are of equal length in the second direction y, or the extension length of the upper beam part 22 in the second direction y is less than that of the lower beam part 23; and the extension length of the lower edge part 13 of the core plate 1 in the second direction y is less than that of the upper edge part 12. In this way, a connection area 231 suitable for external welding can be formed between the end of the lower edge part 13 far from the main core part 11 and the end of the lower beam part 23 far from the main beam part 21. This connection area 231 can provide sufficient operating space when externally connecting the bottom plate 300 of the battery pack. Especially when connecting by welding (such as the FSW friction stir welding connection process), the bonding strength between the lower beam part 23 and the bottom plate 300 can be higher.

[0053] In some embodiments, as Figure 4 and Figure 8 shown, end plates 25 integrally formed with the beam body 2 are respectively provided at both ends of the beam body 2 in the first direction x. The plate surface of the end plate 25 is perpendicular to the first direction x, and the end plate 25 covers the upper beam part 22 upward and the lower beam part 23 downward in the second direction y; and covers the main beam part 21 forward in the third direction z, and covers the end of the upper beam part 22 far from the main beam part 21 and the end of the lower beam part 23 far from the main beam part 21 backward respectively. Through the setting of the end plates 25, on the one hand, the ends of the beam body 2 can be closed at both ends in the first direction x to improve the structural strength of the ends of the beam body 2, and on the other hand, an operating surface for external connection can be provided at the ends of the beam body 2. This operating surface can provide sufficient operating space when externally connecting the side beam 400 of the battery pack. Especially when connecting by welding (such as the CMT cold metal transfer welding connection process), the bonding strength between the beam body 2 and the side beam 400 can be higher.

[0054] Optionally, as Figure 8 shown, the circumferential edge of the end plate 25 can be rounded to form a rounded corner 251 at the circumferential edge of the end plate 25. In this way, on the one hand, the corners at the ends of the beam body 2 can have a continuous and smooth transition, and on the other hand, when the beam body 2 is matched with the side beam 400, a groove can be formed between the rounded corner 251 of the end plate 25 and the inner side surface of the side beam 400. When connecting by welding, especially the CMT connection process, it can provide sufficient welding space for convenient welding and make the bonding strength higher.

[0055] In another embodiment, asFigure 9 As shown, a battery pack is further provided, which includes an upper cover 200, a bottom plate 300, a front cross member 500, a rear cross member (not shown in the figure), and two side beams 400. Both ends of the front cross member 500 are respectively fitted to both ends of the rear cross member through the side beams 400 to enclose a receiving cavity; the upper cover 200 is disposed above the receiving cavity, and the four peripheries of the upper cover 200 are respectively fixedly connected to the front cross member 500, the rear cross member, and the two side beams 400; the bottom plate 300 is attached to the lower side of the receiving cavity, and the four peripheries of the bottom plate 300 are respectively fixedly connected to the front cross member 500, the rear cross member, and the two side beams 400; wherein, at least one of the front cross member 500 and the rear cross member is the cross member structure 100 in any of the above embodiments. It can be understood that, in the above battery pack, for other structures and working principles of the cross member structure 100, please refer to the description of the embodiments of the cross member structure 100 above. Since the cross member structure 100 has the above technical effects, the battery pack having the cross member structure 100 should also have corresponding technical effects, which will not be elaborated here.

[0056] Specifically, in this embodiment, the upper cover 200 of the battery pack can be made of a steel stamping part, an aluminum alloy plate stamping part, an SMC composite material molded plate, etc. according to the configuration. The bottom plate 300 of the battery pack can be made of a large-width aluminum alloy profile welded plate. The side beam 400 can be made of an aluminum profile. Both the front cross member 500 and the rear cross member of the battery pack are the cross member structure 100 in the above embodiments. Taking the connection at the front cross member 500 of the battery pack as an example, as Figure 9As shown in the figure, both ends of the front crossbeam 500, i.e., the crossbeam structure 100, are respectively attached to the relative inner sides of the two side beams 400, and are welded and fixed to the side beams 400 through the CMT (Cold Metal Transfer welding) connection process when the end plates 25 are provided; the upper beam part 22 of the front crossbeam 500, i.e., the crossbeam structure 100, is attached to the lower end surface of the upper cover 200 through the sealant 201 and is connected and fixed to the upper cover 200 through the FDS (Flow Drill Screwing) connection process. At this time, the FDS screws 202 are correspondingly passed through the upper cover 200, the upper beam part 22, and the upper edge part 12, which can make the connection tight and stable; the lower beam part 23 of the crossbeam structure 100 is attached to the upper end surface of the bottom plate 300 and is welded and fixed to the bottom plate 300 through the FSW (Friction Stir Welding) connection process. The welding area is located in the connection area 231 of the lower beam part 23. Since the beam body 2 and the bottom plate 300 are of the same material, the combination of the beam body 2 and the bottom plate 300 is realized through the mechanical friction and plastic flow of the FSW connection process, which can make the weld continuous and the connection quality better; the connection method between the side beam 400 and the upper cover 200 can refer to the connection method between the front crossbeam 500 and the upper cover 200, that is, through the FDS connection process, and the connection method between the side beam 400 and the bottom plate 300 can also refer to the connection method between the front crossbeam 500 and the bottom plate 300, that is, through the FSW connection process. By selecting materials and making connections in the above way, not only can the mechanical and safety performance of the battery pack be effectively improved to meet the strength and stiffness requirements, but also the weight of the battery pack can be reduced, and then the number of battery cells arranged can be increased accordingly, and the energy density of the whole pack can be improved.

[0057] It can be understood that the connection at the rear crossbeam of the battery pack is the same as the connection method at the above-mentioned front crossbeam 500, and will not be elaborated here. In other embodiments, when the size of the battery pack is large, a middle crossbeam will be provided in the middle area of the battery pack to improve the structural strength and provide mounting points for connection with the vehicle body. At this time, the middle crossbeam can be made of aluminum profiles, and its connection methods with the upper cover 200, the bottom plate 300, and the two side beams 400 can refer to the prior art and will not be elaborated here.

[0058] In yet another embodiment, a manufacturing method for the above-mentioned crossbeam structure 100 is also provided. As Figure 10 shown, the method includes:

[0059] S100, stamping a metal material plate with relatively high material strength and relatively high melting point into the core plate 1;

[0060] S200, placing the core plate 1 in a die-casting mold for positioning and fixing. Among them, a die-casting cavity for the beam body 2 is formed between the positioned and fixed core plate 1 and the inner surface of the die-casting mold;

[0061] S300, melting a metal material with relatively low material strength and relatively low melting point into a metal liquid;

[0062] S400, inject the molten metal into the die-casting mold at a preset die-casting temperature for die-casting. After the die-casting part is solidified, cooled and formed, demold and take it out.

[0063] S500, shape and trim the die-casting part to obtain the crossbeam structure 100.

[0064] The crossbeam structure 100 obtained by the above method realizes the effective coating of the core plate 1 inside the beam body 2, improves the structural strength and stiffness, breaks through the single material strength limit of the existing battery pack crossbeam, and thus realizes the structural design combining high strength and light weight overall.

[0065] It can be understood that the equipment, structure, materials, process parameters, etc. adopted in the above method can be obtained through CAE simulation analysis, physical experiments, solid modeling and casting simulation software, and combined with the developed numerical model. Then, casting specimens under different casting conditions are obtained by using orthogonal experiments, and the casting process suitable for mass production is preferably designed by detecting the dimensional accuracy and performance data of the specimens.

[0066] Specifically, in this embodiment, the following equipment, structure, materials and process parameters are adopted to manufacture and form the crossbeam structure 100:

[0067] In step S100, a high-strength steel plate with a relatively thin thickness is used as the core plate 1 after stamping and forming for standby.

[0068] In step S200, switch the die-casting mold to the open mold state to put in the core plate 1. There are support parts for positioning and fixing the core plate 1 formed in the cavity of the die-casting mold to position, support and fix the core plate 1. A die-casting cavity for die-casting the beam body 2 is formed between the positioned and fixed core plate 1 and the inner surface of the die-casting mold cavity. Then, switch the die-casting mold to the closed mold state and control the temperature of the die-casting mold at 160°C to 190°C.

[0069] In step S300, put aluminum alloy ingots into the melting furnace, control the temperature in the melting furnace at 710°C to 755°C to melt the aluminum alloy ingots into aluminum alloy liquid, and let it stand and heat up to the preset die-casting temperature. In this embodiment, the preset die-casting temperature is 745°C to 750°C.

[0070] In step S400, when the aluminum alloy liquid is heated up to the preset die-casting temperature (such as the temperature is 748°C), inject the aluminum alloy liquid into the die-casting mold and use the low-pressure casting method for die-casting. At this time, the temperature of the aluminum alloy liquid in the holding furnace of the die-casting machine is controlled at 695°C to 715°C, the pressure holding time is 190s to 210s, and the cooling time is 120s to 140s. After the die-casting part is solidified, cooled and formed, take out the formed blank part.

[0071] In step S500, a special shaping tooling is installed, the temperature of the blank is maintained at 100°C to 105°C and the mold is pressed and closed, with a pressure of 20 MPa to 25 MPa, and after pressing for 5 minutes, it is demolded and cooled to obtain the shaped die-casting; subsequently, the shaped die-casting is trimmed. Preferably, the special shaping tooling can adopt a trimming die with a shaping function to cut off the flash while performing the shaping pressing; thus, the required crossbeam structure 100 with the beam body 2 covering the core plate 1 is obtained.

[0072] It can be understood that the crossbeam structure 100 obtained by the above process is a rough blank in the casting state, which realizes the preliminary surface treatment of the crossbeam structure 100 and the effective covering of the core plate 1 inside the beam body 2, and further precision machining is required, including but not limited to removing the reverse gate and flash, machining the corresponding mounting interfaces 112, and performing surface roughness treatment, etc., so as to obtain the crossbeam structure 100 product that meets the functions of the front / rear crossbeams of the battery pack. The specific precision machining method is the prior art, which is not limited here and will not be elaborated.

[0073] It can also be understood that after die-casting, holes corresponding to the parts where the core plate 1 is positioned and fixed by the support parts will be formed on the beam body 2. Generally, these holes can be blocked by welding or embedding in subsequent processes, or left untreated, with little impact on the strength of the crossbeam structure 100; optionally, the support parts in the above die-casting mold can also be set at the design positions corresponding to the mounting interfaces 112 of the core plate 1, and the holes left on the beam body 2 caused by the support parts can be used as bolt connection holes for the corresponding interface structures (such as electrical interface structures, etc.) of the mounting interfaces 112 during the subsequent precision machining process to ensure the integrity of the beam body 2 structure without secondary blocking treatment of the holes.

[0074] It can be understood that in this application, unless otherwise clearly specified and limited, terms such as "assembly" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0075] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. The meaning of "a plurality" is two or more, unless otherwise specifically defined. Also, descriptions such as "some embodiments" and "exemplarily" mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application.

[0076] The illustrative representations of the above terms do not necessarily refer to the same embodiments or examples. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0077] Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting the present application. Those of ordinary skill in the art may modify, replace, and vary the above embodiments within the scope of the present application. Therefore, any changes or modifications made in accordance with the claims and the description of the present application shall fall within the scope covered by the patent of the present application.

Claims

1. A crossbeam structure for a battery pack, characterized in that, Comprising: A core plate, the core plate is arranged to extend along a first direction, including a main core part, an upper edge part and a lower edge part. The plate surface of the main core part is perpendicular to a second direction. The upper edge part and the lower edge part are distributed at the upper and lower ends of the main core part along a third direction and respectively extend backward along the second direction. Among them, the first direction, the second direction and the third direction are perpendicular to each other pairwise; A beam body, the beam body is coated on the core plate; among them, the beam body and the core plate are made of different metal materials, and the material strength of the core plate is greater than the material strength of the beam body.

2. The crossbeam structure according to claim 1, wherein, The beam body includes a main beam part, an upper beam part and a lower beam part. The plate surface of the main beam part is perpendicular to the second direction. The upper beam part and the lower beam part are distributed at the upper and lower ends of the main beam part along the third direction and respectively extend backward along the second direction. Among them, the main beam part is coated on the main core part, the upper beam part is coated on the upper edge part, and the lower beam part is coated on the lower edge part.

3. The crossbeam structure according to claim 2, wherein, The upper edge part is provided with a plurality of first weight-reducing holes, and the plurality of first weight-reducing holes are spaced along the first direction on the plate surface of the upper edge part; and / or the lower edge part is provided with a plurality of second weight-reducing holes, and the plurality of second weight-reducing holes are spaced along the first direction on the plate surface of the lower edge part.

4. The crossbeam structure according to claim 2, characterized in that, The main core part is provided with a plurality of third weight-reducing holes, and the plurality of third weight-reducing holes are spaced along the first direction on the plate surface of the main core part; among them, at least one of the third weight-reducing holes is configured as a mounting interface, and the mounting interface penetrates through the plate surfaces of the main beam part and the main core part along the second direction.

5. The crossbeam structure according to claim 2, characterized in that, The beam body further includes a reinforcing rib part, the reinforcing rib part is connected between the upper beam part and the lower beam part and is connected forward to the main beam part along the second direction; the reinforcing rib part includes a plurality of first reinforcing ribs and a plurality of second reinforcing ribs. The plurality of first reinforcing ribs extend along the third direction and are spaced along the first direction. The upper end of the first reinforcing rib is connected to the upper beam part, and the lower end is connected to the lower beam part; the plurality of second reinforcing ribs extend along the first direction and are spaced along the third direction and are cross-connected with the second reinforcing ribs.

6. The crossbeam structure according to claim 2, characterized in that, The cross beam structure further includes a support, the front end of the support is provided with a mounting structure for externally connecting to a vehicle body, the rear end of the support is connected to the beam body, and a plurality of third reinforcing ribs are formed along the circumferential direction of the support extending along the plate surface of the main beam part, and the positive projection of the third reinforcing ribs in the second direction coincides with the plate surface of the main core part.

7. The crossbeam structure according to any one of claims 2-6, characterized in that, The positive projection of the upper beam part in the third direction coincides with the lower beam part; the extension length of the lower edge part in the second direction is less than that of the upper edge part, so that a connection area suitable for external welding is formed between the end of the lower edge part far from the main core part and the end of the lower beam part far from the main beam part.

8. The crossbeam structure according to claim 7, characterized in that, End plates integrally formed with the beam body are provided at both ends of the beam body in the first direction. The plate surface of the end plate is perpendicular to the first direction, and the end plate covers the upper beam portion upward and the lower beam portion downward in the second direction; and covers the main beam portion forward in the third direction, and covers the end of the upper beam portion away from the main beam portion and the end of the lower beam portion away from the main beam portion backward respectively.

9. A battery pack, characterized in that, It includes an upper cover, a bottom plate, a front cross beam, a rear cross beam and two side beams. The two ends of the front cross beam are respectively cooperated with the two ends of the rear cross beam through the side beams to form an accommodation cavity; the upper cover is arranged above the accommodation cavity, and the four sides of the upper cover are respectively fixedly connected with the front cross beam, the rear cross beam and the two side beams; the bottom plate is attached to the lower part of the accommodation cavity, and the four sides of the bottom plate are respectively fixedly connected with the front cross beam, the rear cross beam and the two side beams; wherein, at least one of the front cross beam and the rear cross beam is the cross beam structure described in any one of claims 1-8.

10. A manufacturing method for the crossbeam structure according to claim 1, characterized in that, The method includes: Using a metal material plate with relatively high material strength and relatively high melting point to be formed into the core plate by stamping; Placing the core plate in a die-casting mold for positioning and fixing, wherein a die-casting cavity of the beam body is formed between the positioned and fixed core plate and the inner surface of the die-casting mold; Melting a metal material with relatively low material strength and relatively low melting point into a metal liquid; Injecting the metal liquid into the die-casting mold at a preset die-casting temperature for die-casting. After the die-casting part is solidified and cooled to form, demold and take it out; Performing shaping and trimming on the die-casting part to obtain the cross beam structure.

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