Liquid cooling tray and forming process thereof

Abstract

The application discloses a liquid cooling tray and a forming process thereof, and relates to the field of battery accessory preparation. The forming process comprises the following steps: an initial plate is made of high-strength steel material, and then the initial plate is subjected to pretreatment and cutting treatment respectively to obtain a preformed material and a bottom plate material. A preformed structure is formed at the connecting position of the preformed material. The preformed material is subjected to continuous roll forming treatment to obtain various beam structure parts. The bottom plate material is subjected to shaping treatment to obtain a bottom structure with an assembly reference. Then, the various beam structure parts are positioned and assembled according to the assembly reference to obtain an assembly framework structure on the bottom structure. The beam structure parts in the assembly framework structure are fixedly welded to obtain a connecting framework structure. The connecting framework structure is continuously welded, and the connecting framework structure and the bottom structure are sealed and welded to obtain the liquid cooling tray. The application solves the problem that assembly precision and welding deformation are difficult to be compatible.

Description

Technical Field

[0001] This invention relates to the field of battery accessory manufacturing, and in particular to a liquid-cooled tray and its molding process. Background Technology

[0002] With the rapid development of new energy vehicles, the power battery system, as the core component of the vehicle, has been subject to higher requirements in terms of safety, structural strength and lightweighting. As an important structural component that carries the battery module, the battery tray not only needs to have good load-bearing capacity and impact resistance, but also needs to meet the comprehensive requirements of vehicle lightweighting and cost control.

[0003] Currently, battery trays are mostly made of high-strength steel and manufactured through roll forming and welding processes. Low-heat-input welding to reduce welding deformation and improve structural flatness has become the mainstream technical approach. However, in practical applications, this method suffers from the problem of incompatibility between assembly accuracy and welding deformation. Specifically, battery trays with a grid-like structure featuring multiple intersecting beams have complex structures due to the convergence of longitudinal and transverse beams forming multiple connection nodes. These structures are prone to positioning deviations during assembly, and uneven heating at each node during welding leads to significant differences in local shrinkage. While the aforementioned methods primarily reduce deformation by lowering welding heat input, they struggle to effectively control the overall shrinkage path of the multi-node structure. This results in a trade-off between assembly accuracy and welding deformation, ultimately causing overall structural deformation and reduced surface flatness, affecting the installation accuracy and safety of the battery module.

[0004] In addition, liquid cooling trays usually need to contact and cooperate with liquid cooling plates or cooling pipes to achieve heat conduction and heat dissipation control of battery modules. Therefore, the flatness and structural stability of the bottom structure of the tray not only affect the assembly accuracy, but also further affect the heat transfer efficiency and sealing reliability of the cooling medium. When the tray is deformed during the welding process, it is easy to cause uneven contact or local gaps between it and the liquid cooling structure, thereby reducing the thermal management effect.

[0005] Therefore, a liquid-cooled tray and its molding process are proposed to solve the problem of incompatibility between assembly accuracy and welding deformation. Summary of the Invention

[0006] The purpose of this invention is to provide a liquid-cooled tray and its molding process, which solves the problem of incompatibility between assembly accuracy and welding deformation.

[0007] To achieve this objective, the present invention adopts the following technical solution: A molding process for a liquid-cooled tray, the molding process comprising the following steps: Step S1: The high-strength steel material is made into an initial plate, and then the initial plate is pre-treated and cut to obtain precast material and base plate material respectively; wherein, the connection position of the precast material forms a precast structure; the precast structure includes a through opening, a step structure formed in the edge area of ​​the through opening, and a welding guide edge located at the edge of the precast material, and the through opening and the step structure cooperate with each other. Step S2: The prefabricated material is subjected to continuous roll forming to obtain various beam structural components; Step S3: Shape the base plate material to obtain a bottom structure with assembly reference; then position and assemble various beam structural components according to the assembly reference to obtain an assembly skeleton structure on the bottom structure, wherein the assembly skeleton structure forms an interlocking connection through prefabricated structures. Step S4: Fix the beam structural components in the assembly frame structure by welding to obtain the connecting frame structure; then continuously weld the connecting frame structure and seal the connecting frame structure with the bottom structure to obtain the liquid-cooled tray.

[0008] The prefabricated material is obtained according to the following steps: The initial sheet material is subjected to stamping, partial forming and trimming to obtain prefabricated material with prefabricated structure. The through-hole opening is formed by punching holes at predetermined connection positions on the initial sheet metal; the stepped structure is formed by pressing the edge area of ​​the through-hole opening with a die; the welding guide edge is formed by trimming the edge of the initial sheet metal. The thickness of the prefabricated material is 0.8-1.5 mm, and the yield strength is 980-1500 MPa; the diameter of the through-hole is 10-40 mm, and the positional error is ≤ ±0.2 mm; the depth of the stepped structure is 0.5-2 mm; and the width of the welding guide edge is 2-6 mm.

[0009] The base plate material is obtained according to the following steps: The initial sheet material is repeatedly pressed by multi-roll forming to obtain a trimmed sheet material; then, holes are punched in the trimmed sheet material to form positioning areas, and the edges are trimmed to obtain the base plate material.

[0010] The beam structural member is obtained according to the following steps: Precast materials are fed into a continuous roll forming machine. First, the precast materials are straightened by a straightening mechanism to obtain flat materials. Then, the flat materials are gradually shaped by multiple roll forming units, so that the flat materials are sequentially formed into the target cross-sectional structure along the conveying direction. According to the cross-sectional requirements of different beam structural components, the precast materials are roll-formed using corresponding roller types to obtain shaped materials. Then, the shaped materials are cut to a fixed length to obtain various beam structural components. The beam structural components include front beam structural components, rear beam structural components, side beam structural components, longitudinal module beam structural components, transverse module beam structural components, and transverse end beam structural components.

[0011] The flatness of the straightening treatment is ±0.3mm; the multi-stage roll forming unit consists of 20-40 sections, and the forming speed of the multi-stage roll forming unit is 5-20m / min; the length error of the beam structure is ≤±0.5mm.

[0012] The assembly frame structure is obtained according to the following steps: The base plate material is fed into a shaping device for shaping to form a flat bottom structure, and an assembly reference is formed in the positioning area on the bottom structure. Then, based on the assembly reference, a portion of the beam structural components are positioned and assembled to obtain the outer frame structure. Another portion of the beam structural components are then installed inside the outer frame structure and positioned through a prefabricated structure to obtain the assembled skeleton structure located on the bottom structure.

[0013] The assembly reference includes at least one of positioning holes, positioning surfaces, and positioning boundaries; the outer frame structure includes front beam structural components, rear beam structural components, side beam structural components, and transverse end beam structures; another part of the beam structural components consists of longitudinal module beam structural components and transverse module beam structural components.

[0014] The liquid-cooled tray is obtained according to the following steps: The assembly frame structure is transferred to the welding station, and the beam structural components in the assembly frame structure are fixedly welded at the connection positions to obtain the connecting frame structure; then, continuous welding is performed on the connecting frame structure along each connection position; finally, the connecting frame structure and the bottom structure are sealed and welded at the corresponding connection positions to obtain the liquid-cooled tray.

[0015] The connection locations include cross-connection locations and end connection locations between beam structural members, as well as the connection interface between the connecting frame structure and the bottom structure; the fixed-position welding, continuous welding, and sealing welding are all CMT cold welding; the welding length of the fixed-position welding is 5-20mm, the welding spacing is 20-80mm, and the number of welds is ≥2 for each connection location; the welding current of the continuous welding is 80-140A, the welding speed is 5-15mm / s, and the welding sequence is symmetrical alternating welding; the welding current of the sealing welding is 70-140A, the welding spacing is 20-80mm, and the welding method is intermittent welding.

[0016] A liquid-cooled tray, wherein the liquid-cooled tray is obtained by the molding process described above.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a liquid-cooled tray and its forming process. High-strength steel is used to form an initial plate, resulting in prefabricated materials with prefabricated structures at connection points and a base plate material. The prefabricated materials are then continuously roll-formed to obtain various beam structural components. Simultaneously, the base plate material is shaped to form a bottom structure with assembly references. Subsequently, based on these assembly references, the various beam structural components are positioned and assembled into an interlocking assembly skeleton structure formed by the prefabricated structure. Finally, the assembly skeleton structure undergoes sequential fixation welding, continuous welding, and sealing welding with the bottom structure to obtain the liquid-cooled tray. This process uses the prefabricated structure to mechanically limit the connection nodes before welding, effectively constraining the node positioning deviations of the assembly skeleton structure. This avoids the problem of uneven welding heat input caused by uneven assembly gaps. Furthermore, the step-by-step implementation of fixation welding and continuous welding, combined with a reasonable welding sequence, ensures a balanced distribution of welding heat input along the assembly skeleton structure. The welding shrinkage path changes from random accumulation to controlled release. The bottom structure maintains a stable planar shape during the sealing welding process. Ultimately, the forming process of the multi-node intersecting structure achieves coordinated control of assembly accuracy and welding deformation. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] The structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0020] Figure 1 This is a flowchart of the molding process in this invention; Figure 2 This is a schematic diagram of the overall structure of the liquid-cooled tray in this invention; Figure 3 This is a cross-sectional view of the end beam structure in this invention.

[0021] In the diagram: 1. Bottom structure; 2. Main beam structure; 3. End beam structure; 4. Connection part; 5. Through opening; 6. Step structure; 7. Welded guide edge; 8. Protrusion. Detailed Implementation

[0022] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0023] In the description of this invention, it should be understood that the terms "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be a component positioned centrally in the connection.

[0024] Please see Figure 1 The molding process of a liquid-cooled tray in this embodiment includes the following steps: Step S1: The high-strength steel material is made into an initial plate, and then the initial plate is pre-treated and cut to obtain precast material and base plate material respectively; wherein, the connection position of the precast material forms a precast structure; the precast structure includes a through opening, a step structure formed in the edge area of ​​the through opening, and a welding guide edge located at the edge of the precast material, and the through opening and the step structure cooperate with each other. Step S2: The prefabricated material is subjected to continuous roll forming to obtain various beam structural components; Step S3: Shape the base plate material to obtain a bottom structure with assembly reference; then position and assemble various beam structural components according to the assembly reference to obtain an assembly skeleton structure on the bottom structure, wherein the assembly skeleton structure forms an interlocking connection through prefabricated structures. Step S4: Fix the beam structural components in the assembly frame structure by welding to obtain the connecting frame structure; then continuously weld the connecting frame structure and seal the connecting frame structure with the bottom structure to obtain the liquid-cooled tray.

[0025] Specifically, in step S1, high-strength steel material is made into an initial plate, and then the initial plate is pre-treated and cut to obtain precast material and base plate material respectively; wherein, the connection position of the precast material forms a precast structure; the precast structure includes a through opening, a step structure formed in the edge area of ​​the through opening, and a welding guide edge located at the edge of the precast material, and the through opening and the step structure cooperate with each other. Precast materials are obtained according to the following steps: The initial sheet material is subjected to stamping, partial forming and trimming to obtain prefabricated material with prefabricated structure. The through-hole opening is formed by punching holes at predetermined connection positions on the initial sheet metal; the stepped structure is formed by pressing the edge area of ​​the through-hole opening with a die; the welding guide edge is formed by trimming the edge of the initial sheet metal. The thickness of the precast material is 0.8-1.5mm, and the yield strength is 980-1500MPa; the diameter of the through-hole is 10-40mm, and the positional error is ≤±0.2mm; the depth of the stepped structure is 0.5-2mm; and the width of the welding guide edge is 2-6mm.

[0026] In the molding process of liquid-cooled pallets, the preparation of prefabricated materials is the primary step in resolving the incompatibility between assembly accuracy and welding deformation. In existing technologies, liquid-cooled pallets with multi-beam cross structures are prone to positioning deviations during assembly. This is mainly due to the lack of effective pre-positioning methods for the connection positions between beam structural components, relying solely on welding fixtures or subsequent welding processes to maintain relative positional relationships, leading to increased cumulative errors. To reduce positioning uncertainty during assembly, this step involves prefabricating the initial sheet material during the material preparation stage. By forming prefabricated structures with through openings, stepped structures, and welding guide edges at predetermined connection positions, the beam structural components can achieve mechanical interlocking and precise alignment during subsequent assembly. Simultaneously, clear requirements are set for the thickness, yield strength, and dimensional tolerances of the prefabricated material. This provides a stable and consistent raw material foundation for subsequent roll forming processes, avoiding insufficient interchangeability of the formed beam structural components due to material fluctuations or structural deviations. This establishes a precision control framework at the front end of the process, laying the structural foundation for the coordinated control of assembly accuracy and welding deformation throughout the entire process chain.

[0027] In practice, the prefabricated structure can be fabricated using a continuous stamping die. The punching positions of the through-holes are controlled by locating pins to ensure a positional error of ≤±0.2mm. The stepped structure is formed in a single pressing process, with a depth of 0.5-2mm, to ensure a stable contact and limiting relationship during subsequent assembly. The welding guide edge is formed through a trimming process, with a width of 2-6mm, to ensure the continuity and consistency of the welding area. Through these methods, the prefabricated material possesses stable geometric characteristics before entering subsequent processes, thereby ensuring consistency in the connection positions between different batches of material.

[0028] Under the aforementioned methods, the precast materials not only possess precise geometric features and mechanical performance parameters, but the through-holes and stepped structures on the precast materials also constitute mutually interlocking positioning interfaces, while the welding guide edges provide a uniform and continuous weld bearing area for subsequent welding processes. This precise structural feature, implanted in the initial plate stage, allows the beam structural components subsequently obtained through roll forming to achieve rapid alignment and temporary fixation based on their own structural morphology. This significantly reduces the dependence on external clamps during assembly and improves the dimensional consistency and node positioning accuracy of the assembled skeleton structure.

[0029] The through-hole openings and stepped structures formed on the prefabricated materials enable the assembly skeleton structure to form an interlocking connection through the prefabricated structure during subsequent assembly, providing a basis for solving the problem of assembly deviation. In the existing technology, the intersection nodes of the internal longitudinal and transverse beams of the grid-shaped structure tray rely solely on temporary clamping before welding to maintain their position. However, the local thermal expansion and contraction caused by the welding heat input can easily lead to micro-displacement of the nodes, resulting in cumulative deformation and flatness deterioration of the overall structure. The interlocking connection achieved through the prefabricated structure in this step changes the above situation. Specifically, after the beam structural components are positioned according to the assembly datum, the cooperation between the through-hole openings and the stepped structure ensures that each beam structural component is in a stable mechanical constraint state before welding begins. The relative geometric relationship of the connection position is guaranteed by the prefabricated structure itself, rather than entirely depending on the clamping accuracy during operation. This mechanical interlocking state can effectively suppress component slippage caused by the initial welding stress in the subsequent fixed welding stage, so that the welding thermal shrinkage path is physically limited by the prefabricated structure. This creates conditions for the controllable release of welding deformation while ensuring assembly accuracy, ultimately substantially alleviating the problem of incompatibility between assembly accuracy and welding deformation at the front end of the process.

[0030] The base plate material is obtained according to the following steps: The initial sheet material is repeatedly pressed by multi-roll forming to obtain a trimmed sheet material; then, holes are punched in the trimmed sheet material to form positioning areas, and the edges are trimmed to obtain the base plate material.

[0031] The overall structural precision of a liquid-cooled tray depends not only on the positioning accuracy of the upper frame beams but also heavily on the flatness and datum consistency of the bottom structure. Welding deformation issues in existing technologies are often amplified by unevenness in the bottom support surface, ultimately affecting the installation precision and safety of the battery module. If the bottom material has uneven residual stress distribution or plate shape defects in the initial stage, even with strict deformation control measures in subsequent assembly and welding processes, the overall flatness of the tray bottom surface will still be insufficient to meet high-precision assembly requirements. Therefore, specialized shaping and feature processing of the bottom plate material used to fabricate the bottom structure is necessary during the material preparation stage to eliminate internal stress, correct plate shape defects, and pre-form positioning areas on the bottom plate material for subsequent assembly datum. This pre-processing provides a stable material foundation for the bottom structure, reducing secondary deformation caused by stress release during subsequent welding; it also ensures a unified and accurate reference datum for the subsequent beam structure assembly, thus establishing a complete precision transfer chain from bottom to top, providing underlying support for the coordinated control of assembly precision and welding deformation in the overall process.

[0032] In the specific implementation process, multi-roll forming can adopt a rolling forming method of ≥5 passes. Each pass applies gradually increasing pressure to the initial board material to gradually release the residual stress inside the initial board material. The flatness of the formed trimmed board material is ≤±0.5mm. At the same time, a positioning area is formed on the trimmed board material by CNC punching equipment, with a positional accuracy of ≤±0.2mm, to ensure the consistency of the positioning reference in the subsequent assembly process. During the edge trimming process, burrs and dimensional deviations are removed to ensure the regularity of the bottom plate material boundary, thereby improving the bonding uniformity of the subsequent connection interface.

[0033] In the multi-roll forming process, repeated rolling action releases and balances the residual stress within the initial sheet material, while eliminating the original waviness and warping defects on the surface of the initial sheet material, resulting in a flat, finished sheet material. Based on this, punching processes create positioning areas with preset positional relationships on the finished sheet material, and the corresponding initial sheet material is further trimmed to remove burrs and dimensional deviations, yielding the base plate material. In this process, multi-roll forming significantly improves the flatness of the base plate material, allowing subsequent forming equipment to perform only minor adjustments to obtain a suitable bottom structural plane, and reducing the sensitivity of the bottom structure to welding deformation. Simultaneously, the pre-formed positioning areas on the base plate material provide a precise geometric reference for establishing subsequent assembly datums. When beam structural components are positioned and assembled according to this datum, the relative positional relationship between the assembled frame structure and the bottom structure is precisely controlled, avoiding frame tilting or offset due to inconsistent datums. This ensures the assembly accuracy and dimensional consistency of the overall structure even in the middle of the process.

[0034] The flatness foundation and assembly datum features obtained after multi-roll forming and positioning of the base plate material are directly converted into the flatness accuracy of the bottom structure and the positioning accuracy of the frame structure assembly in subsequent processes. This provides bottom-level constraints to solve the problem of incompatibility between assembly accuracy and welding deformation. During subsequent welding, sealing welding is required between the frame structure and the bottom structure. If the flatness of the bottom structure itself is insufficient or the positioning datum is deviated, the welding heat input will cause uneven thermal expansion and contraction of the bottom structure, resulting in difficult-to-correct wavy deformation on the bottom surface of the pallet. This step, by eliminating the internal stress of the plate material in advance and establishing a precise assembly datum, allows the bottom structure to maintain a relatively stable shape when subjected to welding heat, and the gap at the connection interface between the frame structure and the bottom structure is uniform, providing good welding conditions for sealing welding. This uniform welding interface effectively controls the total amount and distribution of heat input to the bottom structure, ensuring that the final liquid-cooled pallet meets design requirements in terms of overall flatness and module mounting surface accuracy. This achieves synergistic optimization of assembly accuracy and welding deformation at the bottom structure level.

[0035] It should be noted that the coiled high-strength steel material is uncoiled to obtain plate-shaped high-strength steel material; then, the plate-shaped high-strength steel material is straightened by multi-roller straightening equipment to obtain leveled high-strength steel material; then, the leveled high-strength steel material is cut into plates of predetermined width and length by shearing equipment to obtain the initial plates.

[0036] Specifically, in step S2, the prefabricated material is subjected to continuous roll forming to obtain various beam structural components; Beam structural members are obtained according to the following steps: Precast materials are fed into a continuous roll forming machine. First, the precast materials are straightened by a straightening mechanism to obtain flat materials. Then, the flat materials are gradually shaped by multiple roll forming units, so that the flat materials are sequentially formed into the target cross-sectional structure along the conveying direction. According to the cross-sectional requirements of different beam structural components, the precast materials are roll-formed using corresponding roller types to obtain shaped materials. Then, the shaped materials are cut to a fixed length to obtain various beam structural components. The beam structure includes front beam structure, rear beam structure, side beam structure, longitudinal module beam structure, transverse module beam structure, and transverse end beam structure.

[0037] The flatness of the straightening process is ±0.3mm; the multi-pass roll forming unit consists of 20-40 roll forming units, and the forming speed of the multi-pass roll forming unit is 5-20m / min; the length error of the beam structure is ≤±0.5mm.

[0038] The incompatibility between assembly precision and welding deformation in existing technologies stems from insufficient dimensional accuracy and cross-sectional consistency of the various beam structural components forming the grid-like framework. If a beam structural component has a large deviation in the length direction or its cross-sectional profile fluctuates along the length direction, even with the subsequent use of interlocking prefabricated structures and precise assembly benchmarks, the fit clearance at the joints of the assembled framework structure will still be uneven. This leads to uneven heat input distribution and increased local shrinkage differences during welding, ultimately causing overall structural deformation and a decrease in flatness. Therefore, continuous roll forming and fixed-length cutting of prefabricated materials ensures the interchangeability and assembly precision of the various beam structural components. Specifically, the continuous roll forming process in this step uses multiple rollers to progressively bend the prefabricated material, with small and controllable deformation in each pass. This maintains a uniform internal stress distribution in the prefabricated material while obtaining a complex cross-sectional structure that meets design requirements, thus providing various beam structural components with good dimensional consistency, high straightness, and precise cross-sections for subsequent assembly of the framework structure. This step ensures, at both the material and structural levels, that the expected interlocking effect of the prefabricated structure is achieved at each connection node during the subsequent assembly stage.

[0039] In the specific implementation process, continuous roll forming adopts 20-40 roll forming units for step-by-step forming. The deformation of each segment is controlled within the allowable deformation range of the precast material to avoid stress concentration caused by excessive local deformation. The forming speed is controlled at 5-20m / min to balance forming efficiency and forming quality. During the roll forming process, the precast material is straightened online to control its flatness within ±0.3mm to ensure the stability of the cross-sectional shape during the forming process. After forming, laser fixed-length cutting is used for segmentation to control the length error of the beam structure within ±0.5mm, thereby ensuring the assembly interchangeability between different structural components.

[0040] In the above steps, the precast material is straightened by a straightening mechanism to achieve a flatness of ±0.3mm, thereby eliminating the adverse effects of the precast material's shape deviation on the subsequent roll forming accuracy. The straight material is then passed sequentially through 20-40 roll forming units at a forming speed of 5-20m / min, allowing it to undergo multiple small-deformation bends along the conveying direction to ultimately form the target cross-sectional structure stably. Different roll types are used for forming different beam types, such as front beam, rear beam, side beam, longitudinal module beam, transverse module beam, and transverse end beam. Finally, the formed material is cut to a fixed length, ensuring that the length error of each type of beam structure is ≤±0.5mm. Through the above steps, the beam structural components have highly consistent cross-sectional profiles and geometric dimensions along the length direction, and the straightness and length accuracy meet the requirements of precision assembly. At the same time, the through openings and stepped structures processed on the prefabricated materials are completely preserved during the rolling process and form a definite relative positional relationship with the beam cross-section, so that each beam structural component has the precise interface features necessary for subsequent interlocking assembly.

[0041] The continuous roll forming process described above ensures the uniformity of the height dimensions of the beam structural components, thus laying the foundation for solving the problems of accumulated assembly deviations and uneven welding shrinkage at multiple nodes. Specifically, in a grid-like structure with multiple intersecting beams, there are multiple cross or T-shaped connection nodes between various beam structural components. If the cross-sectional height or width of the various beam structural components differs, the contact state at the nodes will exhibit localized suspension or uneven interference fit, leading to a decrease in arc stability during welding, and an inability to uniformly transfer heat input to the base materials on both sides of the joint. This, in turn, increases the dispersion of cooling shrinkage at each node, making the overall structural deformation difficult to predict and control. The high precision of the cross-sectional fit of the beam structural components obtained in this step allows for a uniform and controllable gap distribution at each connection node during the assembly stage. The through-hole openings and stepped structures in the prefabricated structure can naturally fit together without forced external force, and the interlocking state is stable and reliable. Based on this, when subsequent fixed welding and continuous welding processes are applied to the connection positions with consistent geometric relationships, the influence of the welding thermal cycle on each node tends to be equal, and the implementation effects of different welding methods can be fully utilized. As a result, the welding shrinkage path of the overall structure changes from a random distribution to a regular symmetrical distribution, effectively suppressing the cumulative transmission of local deformation to the overall structure, and ultimately achieving coordinated control of assembly accuracy and welding deformation.

[0042] Specifically, in step S3, the base plate material is shaped to obtain a bottom structure with assembly reference; then, various beam structural components are positioned and assembled according to the assembly reference to obtain an assembly skeleton structure located on the bottom structure, wherein the assembly skeleton structure forms an interlocking connection through prefabricated structures. The assembly skeleton structure is obtained according to the following steps: The base plate material is fed into a shaping device for shaping to form a flat bottom structure, and an assembly reference is formed in the positioning area on the bottom structure. Then, based on the assembly reference, a portion of the beam structural components are positioned and assembled to obtain the outer frame structure. Another portion of the beam structural components are then installed inside the outer frame structure and positioned through a prefabricated structure to obtain the assembled skeleton structure located on the bottom structure.

[0043] The assembly reference includes at least one of positioning holes, positioning surfaces, and positioning boundaries; the outer frame structure includes front beam structural components, rear beam structural components, side beam structural components, and transverse end beam structures; another part of the beam structural components consists of longitudinal module beam structural components and transverse module beam structural components.

[0044] In the liquid-cooled pallet forming process, after the beam structural components are prepared, they need to be combined with the bottom structure to form the main skeleton of the pallet. However, liquid-cooled pallets with multi-beam intersection features are prone to positioning deviations during assembly. If these deviations are not effectively constrained before welding, they will be further amplified and solidified into permanent deformation under the heat of welding, resulting in a vicious cycle between assembly accuracy and welding deformation. Therefore, this step establishes a unified assembly benchmark and utilizes the interlocking relationship between prefabricated structures to accurately determine the relative spatial position of all beam structural components and the bottom structure before the welding process begins, and implements temporary mechanical locking. This controls the assembly deviations and provides a geometrically stable and internally constrained welding object for subsequent welding processes. The bottom plate material is shaped to obtain a bottom structure with assembly reference, providing a reliable flatness and a clear reference point for the formation of the entire skeleton. The front beam structure, rear beam structure, side beam structure, longitudinal module beam structure, transverse module beam structure and transverse end beam structure are assembled in layers according to the assembly reference. This is to ensure that each intersection node in the grid-shaped skeleton can be accurately aligned according to the design intention, so that the assembled skeleton structure has a high geometric accuracy and structural rigidity foundation before entering the welding station.

[0045] Under the aforementioned methods, the bottom structure, through shaping, achieves a flatness foundation that meets the requirements of subsequent assembly. The assembly datum on it provides a unified coordinate reference for the spatial positioning of all beam structural components, eliminating the cumulative assembly errors caused by inconsistent datums. The pre-assembly of the outer frame structure establishes stable external boundary constraints. The embedded installation of the internal longitudinal and transverse module beam structural components achieves precise alignment and node interlocking under the guidance of the prefabricated structure. This allows the entire assembled skeleton structure to have a definite geometric shape and a certain degree of structural integrity even before any welding operations are carried out. The gaps at each connection node are evenly distributed and the contact state is stable, providing ideal process conditions for the implementation of subsequent welding procedures.

[0046] In the application of liquid cooling trays, the bottom structure usually serves as the interface that contacts the liquid cooling plate. Its flatness directly affects the heat transfer efficiency and contact stability of the cooling medium. By shaping the bottom plate material and establishing assembly benchmarks, the bottom structure can have a high degree of flatness consistency, which is conducive to achieving uniform contact of the liquid cooling structure during subsequent use, thereby improving heat conduction efficiency.

[0047] In the specific implementation process, the assembly datum adopts a combination of positioning holes and positioning surfaces. The positioning holes are used to define the position in the plane, and the positioning surfaces are used to control the position in the height direction, thus forming a three-dimensional positioning constraint. During the assembly process, the positioning of the outer frame structure is completed first to form a stable boundary constraint. Then, the internal structural components are installed in sequence, so that each connection position can be naturally fitted through the prefabricated structure. The fitting clearance of each connection position is controlled within 0.1-0.3mm to ensure that both smooth assembly and good contact state are formed in the subsequent connection process, thereby improving the stability of the overall structure.

[0048] The assembled skeleton structure, through the interlocking connection formed by the prefabricated structure and the high-precision positioning achieved based on a unified assembly benchmark, provides a structural constraint mechanism to solve the problem of balancing assembly deviation and welding deformation in multi-node structures. Specifically, in traditional processes, the intersection nodes of longitudinal and transverse beams rely solely on clamps to maintain their relative positions. Local thermal expansion caused by welding heat input can easily overcome the friction of the clamps or the pre-tightening force, leading to micro-displacement of the nodes. Furthermore, the direction and amplitude of displacement of each node exhibit random distribution characteristics due to different constraint states, making it difficult to predict and control the overall structural deformation path. In the assembled skeleton structure obtained in this step, the interlocking cooperation between the through opening and the stepped structure provides a pair of stable mechanical limits for each connection node. These limits can effectively resist the redistribution of node positions by weld shrinkage stress during welding heating, thereby restricting the displacement degrees of freedom of each node within the range allowed by the prefabricated structure's fit clearance. Meanwhile, a unified assembly standard ensures that the connection interface between the bottom structure and the frame beam system (the beam network connecting all beam structural members in the frame structure) maintains a uniform contact state throughout the entire circumference (the entire contact boundary along the circumferential edge of the bottom structure and the corresponding areas of the internal longitudinal and transverse beams), creating conditions for uniform heat input during subsequent sealing welding. This step transforms the random accumulation of welding deformation from an unconstrained state into a controllable release under the constraints of the prefabricated structure, thus achieving a synergy between ensuring assembly accuracy and suppressing welding deformation.

[0049] Specifically, in step S4, the beam structural components in the assembly frame structure are fixedly welded to obtain the connecting frame structure; then the connecting frame structure is continuously welded, and the connecting frame structure is sealed and welded to the bottom structure to obtain the liquid-cooled tray.

[0050] The liquid-cooled tray is obtained according to the following steps: The assembly frame structure is transferred to the welding station, and the beam structural components in the assembly frame structure are fixedly welded at the connection positions to obtain the connecting frame structure; then, continuous welding is performed on the connecting frame structure along each connection position; finally, the connecting frame structure and the bottom structure are sealed and welded at the corresponding connection positions to obtain the liquid-cooled tray.

[0051] Connection locations include cross connections and end connections between beam structural members, as well as the connection interface between the connecting frame structure and the bottom structure; fixed-position welding, continuous welding, and sealing welding are all CMT cold welding; the welding length for fixed-position welding is 5-20mm, the welding spacing is 20-80mm, and the number of welds is ≥2 for each connection location; the welding current for continuous welding is 80-140A, the welding speed is 5-15mm / s, and the welding sequence is symmetrical alternating welding; the welding current for sealing welding is 70-140A, the welding spacing is 20-80mm, and the welding method is intermittent welding.

[0052] In existing technologies, liquid-cooled trays with multi-beam cross structures experience uneven heating at each connection node during welding, resulting in significant local shrinkage differences. Simply reducing the welding heat input is insufficient to effectively control the overall shrinkage path of the multi-node structure, leading to overall structural deformation and reduced surface flatness. Even after the assembly frame structure is precisely positioned using prefabricated interlocking and assembly datum, although the relative geometric relationships of each component are initially guaranteed, if the welding process implementation fails to match the structural constraints, the welding thermal cycle can still easily cause slight coordinated displacements in the interlocked nodes under thermal stress, partially negating the assembly precision accumulated in previous processes. Therefore, this step, through a three-stage welding process arrangement of fixed-position welding, continuous welding, and sealing welding, combined with a symmetrical alternating welding sequence and intermittent welding method, can effectively manage the shrinkage path while ensuring the fusion quality at each connection point, ultimately obtaining a liquid-cooled tray that meets both strength requirements and high geometric precision. Meanwhile, the cross-connection points between beam structural components, the end connection points, and the connection interfaces between the connecting skeleton structure and the bottom structure are all welded in stages with controllable heat input. This allows the welding energy to be input and released in an orderly manner along a predetermined path, thereby minimizing the adverse effects of welding deformation on the overall structural accuracy while completing the permanent connection.

[0053] In the specific implementation process, fixed-position welding is symmetrically arranged at each connection position, with ≥2 weld points to ensure the stability of the initial connection; the continuous welding stage adopts a symmetrical alternating welding sequence, that is, welding is carried out alternately on both sides of the structure's center line to achieve a balanced distribution of heat input; the sealing welding adopts an intermittent welding method, with a weld spacing of 20-80mm, to reduce the problem of concentrated heat input caused by continuous welds; the CMT cold welding process is used during the welding process, with the welding current controlled at 70-140A and the welding speed controlled at 5-15mm / s, thereby reducing the range of heat-affected zone while ensuring the connection strength.

[0054] Under the aforementioned methods, fixed-position welding provides preliminary metallurgical bonding points for the connection nodes of each beam structural component based on the interlocking of the prefabricated structure, enabling the assembled skeleton structure to have structural stiffness to resist thermal deformation before the subsequent continuous welding begins; the use of symmetrical alternating welding sequence during continuous welding ensures that the welding heat input is distributed relatively evenly on both sides of the structure, avoiding asymmetrical shrinkage and bending deformation caused by concentrated heating on one side; the intermittent welding method used in sealing welding controls the total amount and continuity of heat input at the connection interface between the connecting skeleton structure and the bottom structure, reducing the disturbance to the flatness of the bottom structure caused by the shrinkage of large-scale continuous welds.

[0055] The segmented welding process, consisting of fixed-position welding, continuous welding, and sealing welding, combined with the low heat input characteristics of CMT cold welding, resolves the contradiction between uneven shrinkage and uncontrollable overall deformation in multi-node welding. Specifically, in the traditional one-time continuous welding method, the heat input at the intersection of beam structural components lacks effective control in both time and space. The stress generated by the cooling shrinkage of the weld is freely transmitted and accumulated along the skeleton structure, leading to unpredictable warping and torsional deformation of the entire tray. In this step, fixed-position welding first establishes discrete constraint weld points at the key locations of the interlocking nodes. These weld points transform the mechanical interlocking state formed by the prefabricated structure into a local metallurgical connection state with higher stiffness, restricting the degree of freedom of relative displacement between nodes during subsequent continuous welding. The symmetrical alternating welding sequence used in the continuous welding stage further optimizes the spatiotemporal distribution of heat input, making the heating and cooling processes on both sides of the structure basically synchronized. This transforms the welding shrinkage stress into a symmetrical self-balancing stress system within the structure, rather than macroscopic geometric deformation. The intermittent welding method in the sealing welding stage effectively avoids local depressions or wavy deformations in the bottom structure caused by concentrated heat input from continuous long welds. Through the synergistic effect of the above three-stage welding process, the liquid-cooled tray can maintain the assembly accuracy and bottom flatness established in the previous process after all permanent connections are completed, thus achieving a balance between ensuring assembly accuracy and suppressing welding deformation under complex welding conditions with multiple nodes.

[0056] Since the liquid cooling tray needs to be coordinated with the cooling medium circulation path in the liquid cooling system during use, the stability of the connection interface has a significant impact on the overall sealing performance. By controlling the welding path and heat input, a continuous and stable connection interface can be formed between the connecting skeleton structure and the bottom structure, which helps to reduce the risk of seal failure caused by structural deformation, thereby improving the reliability of the liquid cooling system.

[0057] In this embodiment, by forming a prefabricated structure on prefabricated materials, establishing an assembly benchmark at the base plate material stage, and coordinating a phased connection process at the assembly and connection stages, a continuous and coordinated control relationship is formed between structural positioning, assembly constraints, and connection processes. The prefabricated structure is used to define the relative relationship of connection positions, the assembly benchmark is used to unify the overall positioning reference, and the connection process is used to control the deformation release path, thereby achieving overall control over structural accuracy and deformation behavior throughout the entire manufacturing process.

[0058] It should be noted that, in the above method, the prefabricated structure formed in step S1 is used to define the relative geometric relationship of each connection position, the assembly datum established in step S3 is used to unify the overall positioning reference, and the staged welding process in step S4 is used to control the welding heat input and shrinkage path. These three steps form a continuous and coordinated control relationship in the process. The prefabricated structure provides local constraints, the assembly datum provides overall constraints, and the welding process achieves controlled release, thereby achieving coordinated control of assembly accuracy and welding deformation in the entire process.

[0059] The liquid-cooled tray obtained through the above process has a bottom structure that can serve as a mounting base for liquid-cooled plates or cooling pipes. While ensuring structural strength and dimensional accuracy, it is beneficial to improve the contact uniformity and heat transfer efficiency of the liquid-cooling system, thereby meeting the comprehensive requirements of power battery systems for structural accuracy and thermal management performance.

[0060] The present invention also proposes a liquid-cooled tray, which is obtained by the above molding process. For specific preparation methods, please refer to Examples 1, 2 and 3.

[0061] like Figure 2 , 3As shown, the liquid-cooled tray includes an end beam structure 3 and a main beam structure 2. The end beam structure 3 and the main beam structure 2 are connected by a prefabricated structure. The prefabricated structure includes a through opening 5, a stepped structure 6, and a welding guide edge 7. A connecting part 4 is formed in the end beam structure 3. The through opening 5 is formed on the connecting plate. The stepped structure 6 is set in the edge area of ​​the through opening 5 and has a concave stepped profile. A protrusion 8 is formed on the end of the main beam structure 2 corresponding to the through opening 5. When the end beam structure 3 and the main beam structure 2 are connected, the protrusion 8 passes through the through opening 5 and connects with the stepped structure 6. The welding guide edge 7 is formed on the edge area of ​​the connecting part 4 corresponding to the periphery of the through opening 5 and the edge area exposed after the protrusion 8 passes through the through opening 5.

[0062] It should also be noted that the various processing methods for materials described above are all technical means well known to those skilled in the art, and will not be described further in this embodiment.

[0063] Example 1: Step S1: Select high-strength steel material with a yield strength of 1180MPa and a thickness of 1.2mm, and obtain the initial plate through uncoiling, leveling and shearing; perform stamping on the initial plate to form a 20mm diameter through-hole at the connection position, and form a stepped structure with a depth of 1mm by pressing with a die, while forming a 4mm wide welding guide edge on the edge of the plate to obtain the precast material; perform multi-roll forming on another part of the initial plate, and the flatness after forming is ±0.5mm, and punch holes to form a positioning area to obtain the base plate material.

[0064] Step S2: The precast material is fed into a continuous roll forming equipment and formed at a speed of 10m / min through 30 roll forming units to obtain various beam structural components with a length error of ±0.5mm.

[0065] Step S3: After shaping the base plate material to form the bottom structure, use the positioning holes as the assembly reference to position and assemble each beam structural component, and form an interlocking connection through the prefabricated structure.

[0066] Step S4: Welding is performed using CMT cold welding. The welding length for stationary welding is 10mm and the welding spacing is 50mm. For continuous welding, the welding current is 100A and the welding speed is 10mm / s, with symmetrical alternating welding. For sealing welding, intermittent welding is used with a welding spacing of 40mm.

[0067] The final liquid-cooled tray has a bottom surface flatness of ±1mm.

[0068] Example 2: The basic content is the same as in Example 1, except that: Step S1: Select high-strength steel material with a yield strength of 980MPa and a thickness of 1.0mm; the diameter of the through-hole is 15mm, the depth of the step structure is 0.8mm, and the width of the welding guide edge is 3mm.

[0069] Step S2: Continuous roll forming uses 25 roll forming units with a forming speed of 8m / min.

[0070] Step S4: The welding length for fixed welding is 8mm and the welding spacing is 40mm; the welding current for continuous welding is 90A and the welding speed is 8mm / s; the welding spacing for sealing welding is 30mm; the flatness of the bottom surface of the liquid cooling tray is ±1.2mm.

[0071] Example 3: The basic content is the same as in Example 1, except that: Step S1: The through-hole in the prefabricated structure is an elongated oval hole structure, and the stepped structure is a double-sided stepped structure.

[0072] Step S3: The positioning area includes the positioning hole and the positioning boundary.

[0073] Comparative Example 1: The basic content is the same as in Example 1, except that: In step S1, the initial sheet material is no longer stamped or partially formed; it is simply cut into strips of the corresponding size.

[0074] In step S3, each beam structural component is clamped and positioned using a fixture.

[0075] In step S4, the welding process adopts a conventional one-time continuous full welding process with a welding current of 100A.

[0076] In application, due to the lack of mechanical interlocking of prefabricated structures, the nodes in Comparative Example 1 experienced significant positional shifts under thermal stress during the welding process. Furthermore, continuous welding on one side resulted in concentrated heat input, ultimately causing visible wave deformation on the bottom surface of the liquid-cooled tray. The flatness of the bottom surface was measured to be ±2.8mm, which failed to meet the installation accuracy requirements of the battery module.

[0077] The following is a comparison of the data between Example 1 and Comparative Example 1, as detailed in Table 1: Table 1 The flatness of the bottom structure is checked by scanning the grid points on the bottom surface with a coordinate measuring machine, and the data is processed according to the flatness tolerance evaluation principle. The gap deviation of the connection node is directly measured by feeler gauge and image measuring instrument before welding, and the judgment is made according to the general tolerance evaluation method of welded structure. The airtightness test of the assembly interface is performed by calculating the leakage rate of the closed cavity under 30kPa pressure using the pressure drop method, which is carried out according to the basic design principle of sealed cavity. The macroscopic state of welding deformation is qualitatively evaluated by visual observation and comparison with the light transmission gap of the platform, referring to the general principles of deformation classification and control of welded components.

[0078] As shown in Table 1, Example 1 employs a molding process with prefabricated structure interlocking and step-by-step welding control, achieving a bottom structure flatness of 1.0 mm. Comparative Example 1, lacking prefabricated structure constraints and using a conventional continuous welding process, achieves a bottom structure flatness of 2.8 mm. The flatness deviation of Example 1 is reduced from 2.8 mm to 1.0 mm, a reduction of approximately 64%. This indicates that the process of the present invention effectively suppresses macroscopic warping deformation of the bottom structure caused by welding heat input, providing a flat bearing reference surface for the precise installation of the battery module. Regarding the connection node gap deviation, Example 1 controls the node positioning deviation to within 0.2 mm through the interlocking cooperation of the through-hole and stepped structure, while Comparative Example 1 relies solely on fixture positioning, resulting in a gap deviation > 0.5 mm. Example 1 significantly improves the node assembly accuracy, fundamentally reducing the problem of welding heat input dispersion caused by uneven fitting gaps. The airtightness test results of the assembly interface showed that the leakage rate of Example 1 under a pressure of 30 kPa was 45 Pa / min, while that of Comparative Example 1 was 250 Pa / min. The sealing reliability of Example 1 was improved by approximately 82%. This difference is directly due to the improved uniformity of the tray and liquid cooling components resulting from the improved flatness of the bottom structure, thus ensuring the long-term sealing stability of the liquid cooling system in actual operation. In terms of the macroscopic state of welding deformation, Example 1 exhibited symmetrical shrinkage and visually flat characteristics, while Comparative Example 1 showed obvious asymmetrical torsional deformation. This indicates that the symmetrical alternating welding sequence and segmented heat input strategy in Example 1 successfully transformed the welding shrinkage stress into a self-balancing stress field inside the structure, avoiding the cumulative transmission of deformation to the overall structure. The above four comparative results together prove that the process scheme of Example 1 effectively solves the core contradiction in the background technology where assembly accuracy and welding deformation are incompatible.

[0079] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A molding process for a liquid-cooled tray, characterized in that, The molding process includes the following steps: Step S1: The high-strength steel material is made into an initial plate, and then the initial plate is pre-treated and cut to obtain precast material and base plate material respectively; wherein, the connection position of the precast material forms a precast structure; the precast structure includes a through opening, a step structure formed in the edge area of ​​the through opening, and a welding guide edge located at the edge of the precast material, and the through opening and the step structure cooperate with each other. Step S2: The prefabricated material is subjected to continuous roll forming to obtain various beam structural components; Step S3: Shape the base plate material to obtain a bottom structure with assembly reference; then, based on the assembly reference, position and assemble the front beam structure, rear beam structure, side beam structure, and transverse end beam structure to obtain the outer frame structure; then, install the longitudinal module beam structure and the transverse module beam structure inside the outer frame structure and position them through prefabricated structures to obtain the assembly skeleton structure located on the bottom structure; wherein, the assembly skeleton structure forms an interlocking connection through prefabricated structures; the assembly reference includes at least one of positioning holes, positioning surfaces, and positioning boundaries. Step S4: Fix the beam structural components in the assembly frame structure to obtain the connecting frame structure; then perform symmetrical alternating continuous welding along each connection position on the connecting frame structure; then perform intermittent sealing welding between the connecting frame structure and the bottom structure at the corresponding connection positions to obtain the liquid-cooled tray.

2. The molding process of the liquid-cooled tray according to claim 1, characterized in that, The prefabricated material is obtained according to the following steps: The initial sheet material is subjected to stamping, partial forming and trimming to obtain prefabricated material with prefabricated structure. The through-hole opening is formed by punching holes at predetermined connection positions on the initial sheet metal; the stepped structure is formed by pressing the edge area of ​​the through-hole opening with a die; the welding guide edge is formed by trimming the edge of the initial sheet metal. The thickness of the precast material is 0.8-1.5 mm, and the yield strength is 980-1500 MPa; the diameter of the through-hole is 10-40 mm, and the positional error is ≤ ±0.2 mm; the depth of the stepped structure is 0.5-2 mm. The width of the welding guide edge is 2-6mm.

3. The molding process of the liquid-cooled tray according to claim 2, characterized in that, The base plate material is obtained according to the following steps: The initial sheet material is repeatedly pressed by multi-roll forming to obtain a trimmed sheet material; then, holes are punched in the trimmed sheet material to form positioning areas, and the edges are trimmed to obtain the base plate material.

4. The molding process of the liquid-cooled tray according to claim 3, characterized in that, The beam structural member is obtained according to the following steps: The precast material is fed into a continuous roll forming equipment. First, the precast material is straightened by a straightening mechanism to obtain a flat material. Then, the flat material is gradually formed by multiple roll forming units, so that the flat material is formed into the target cross-section structure along the conveying direction. According to the cross-section requirements of different beam structural components, the precast material is roll-formed using corresponding roller types to obtain the formed material. The formed material is then cut to a fixed length to obtain various beam structural components; The beam structural components include front beam structural components, rear beam structural components, side beam structural components, longitudinal module beam structural components, transverse module beam structural components, and transverse end beam structural components.

5. The molding process of the liquid-cooled tray according to claim 4, characterized in that, The flatness of the straightening treatment is ±0.3mm; the multi-stage roll forming unit consists of 20-40 sections, and the forming speed of the multi-stage roll forming unit is 5-20m / min; the length error of the beam structure is ≤±0.5mm.

6. The molding process of the liquid-cooled tray according to claim 5, characterized in that, The assembly reference is obtained according to the following steps: The base plate material is fed into the shaping equipment for shaping, so that the base plate material forms a flat bottom structure, and an assembly reference is formed in the positioning area on the bottom structure.

7. The molding process of the liquid-cooled tray according to claim 6, characterized in that, The liquid-cooled tray is obtained according to the following steps: The assembly frame structure is transferred to the welding station, and the beam structural components in the assembly frame structure are fixedly welded at the connection positions to obtain the connecting frame structure; then, continuous welding is performed on the connecting frame structure along each connection position; finally, the connecting frame structure and the bottom structure are sealed and welded at the corresponding connection positions to obtain the liquid-cooled tray.

8. The molding process of the liquid-cooled tray according to claim 7, characterized in that, The connection locations include cross-connection locations and end connection locations between beam structural members, as well as the connection interface between the connecting frame structure and the bottom structure; the fixed-position welding, continuous welding, and sealing welding are all CMT cold welding; the welding length of the fixed-position welding is 5-20mm, the welding spacing is 20-80mm, and the number of welds is ≥2 for each connection location; the welding current of the continuous welding is 80-140A, the welding speed is 5-15mm / s, and the welding sequence is symmetrical alternating welding; the welding current of the sealing welding is 70-140A, the welding spacing is 20-80mm, and the welding method is intermittent welding.

9. A liquid-cooled tray, characterized in that, The liquid-cooled tray is obtained using the molding process described in any one of claims 1-8.

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