A processing method for an aluminum die-cast battery pack cooling module

Abstract

The present invention discloses a processing method for an aluminum die-cast battery pack cooling module, comprising the following steps: preparing a blank body of a bottom shell by an aluminum die-casting process, wherein a second side surface of the blank body has a grid-like protrusion; preparing an aluminum alloy cover plate; placing the aluminum alloy cover plate on a first side surface of the blank body; welding and encapsulating the aluminum alloy cover plate and the blank body by friction welding to form an assembly; performing machining on the assembly, adjusting the dimensions by surplus cutting and removing the grid-like protrusion; performing surface insulation treatment on the machined assembly; the advantages are that the processing method is simple, the manufacturing cost is low, and the product quality is better.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy vehicle battery packs, and particularly to a processing method for an aluminum die-cast battery pack cooling module. Background Art

[0002] With the rapid development of the new energy vehicle industry, the thermal management technology of battery packs has become one of the key factors affecting vehicle performance and safety. During the operation of the battery pack, a large amount of heat is generated. If effective heat dissipation cannot be achieved, it will lead to a decline in battery performance, shortening of battery life, and even safety accidents. Therefore, it is of great significance to develop an efficient and reliable battery pack cooling plate.

[0003] Patent CN219321443U discloses a cooling plate for a new energy vehicle battery pack. This patent discloses a cooling plate composed of two first cooling plates and second cooling plates with the same size. The two cooling plates are connected by friction stir welding process. The first cooling plate is provided with a water cooling area, in which a first cooling water channel and a second cooling water channel are opened. The first cooling water channel and the second cooling water channel are prepared by etching process. The cooling water channels of this cooling plate are prepared by etching process, which increases the processing difficulty, resulting in a reduction in production efficiency and poor product consistency.

[0004] Patent CN221613985U discloses a cooling device and a battery pack. The cooling device includes a liquid cooling plate and two connecting members. The liquid cooling plate is provided with a first layer of cooling channels and a second layer of cooling channels penetrating along a first direction. The two connecting members are respectively assembled with both ends of the liquid cooling plate, so that the penetrated liquid cooling plate is encapsulated to form a complete flow channel structure.

[0005] It can be seen that there are many deficiencies in the traditional cooling plates for new energy vehicle battery packs. Firstly, it is usually formed by aluminum alloy machining method, and its processing technology is complex. Laser etching and other methods are required to process the flow channels, which not only increases the production cost but also limits the improvement of production efficiency. Secondly, even if some structures adopt die-casting process, there are still problems that fasteners and seals need to be used during the assembly process, which makes the structure relatively complex, increasing the assembly difficulty and time cost. In addition, due to the complexity of processing and assembly, the product consistency is also poor.

[0006] These problems not only increase the manufacturing cost but also affect the performance and reliability of the product. Therefore, it has become an urgent need for the current technological development to develop a cooling plate with a simple structure, high manufacturing efficiency, and reliable performance. Summary of the Invention

[0007] In view of this, the technical problem to be solved by the present invention is to provide a processing method for a battery pack cooling module with a simpler process, higher production efficiency, and better quality stability. The core of its technology lies in preparing an integrated water-cooled plate through die casting of aluminum combined with friction welding, and through the design of the structure of the formed intermediate body, avoiding the surface defect problems caused by die casting of aluminum, thereby simplifying the production process, improving production efficiency, and ensuring the quality of the product, providing a better solution for the thermal management of new energy vehicle battery packs.

[0008] The technical solution adopted by the present invention to solve the above technical problems is as follows: A processing method for an aluminum die-cast battery pack cooling module, the aluminum die-cast battery pack cooling module includes an aluminum die-cast bottom shell and an aluminum alloy cover plate; the first side of the bottom shell has a flow channel groove with an upper opening, a flow channel partition wall is provided in the flow channel groove, and the side of the bottom shell has a water inlet and a water outlet communicating with the flow channel groove; the aluminum alloy cover plate is arranged on the bottom shell and closes the flow channel groove;

[0009] The processing method includes the following steps:

[0010] Step A: Prepare a blank body of the bottom shell through die casting of aluminum, and the second side of the blank body has a grid-like protrusion;

[0011] Step B: Prepare the aluminum alloy cover plate;

[0012] Step C: Place the aluminum alloy cover plate on the first side of the blank body;

[0013] Step D: Use friction welding to weld and encapsulate the aluminum alloy cover plate and the blank body to form an assembly;

[0014] Step E: Perform machining on the assembly, adjust the dimensions through surplus cutting, and remove the grid-like protrusion;

[0015] Step F: Perform surface insulation treatment on the machined assembly.

[0016] The preferred technical solution adopted by the present invention to solve the above technical problems is: In step B, the aluminum alloy cover plate is prepared through an extrusion molding process.

[0017] The preferred technical solution adopted by the present invention to solve the above technical problems is: In step F, the surface insulation treatment is prepared through electrophoresis or powder spraying process.

[0018] The preferred technical solution adopted by the present invention to solve the above technical problems is: The grid-like protrusion is a uniform diamond grid.

[0019] The preferred technical solution adopted by the present invention to solve the above technical problems is: The edge width of the grid-like protrusion gradually decreases from the root to the end face, and the end face is a plane.

[0020] The preferred technical solution adopted by the present invention to solve the above technical problems is that: the edge height of the grid-like protrusions is 0.3 mm - 0.5 mm.

[0021] The preferred technical solution adopted by the present invention to solve the above technical problems is that: step F is prepared by a powder spraying process, and the step F includes the following sub-steps:

[0022] Step F1: Bake to discharge the gas in the surface pores;

[0023] Step F2: Spray a layer of base powder on the surface to form a sealing layer;

[0024] Step F3: Spray flour to complete the surface treatment.

[0025] The preferred technical solution adopted by the present invention to solve the above technical problems is that: before step D, the blank body is subjected to a primary leveling treatment, and the primary leveling treatment sequentially includes a primary mechanical shaping treatment and a heat treatment annealing process treatment, and the annealing temperature is controlled at 255 - 265 °C.

[0026] The preferred technical solution adopted by the present invention to solve the above technical problems is that: before step E, the assembled body after welding in step D is subjected to a secondary mechanical shaping treatment to control the overall flatness.

[0027] Compared with the prior art, the advantages of the present invention are as follows: First, by adopting the technology of combining integrated aluminum die-casting molding and friction welding, the traditional welding and assembly combination of multiple parts is reduced to the welding combination of two main parts. This design eliminates the complex assembly process and the required fasteners and seals, greatly simplifies the production process, and reduces the manufacturing cost.

[0028] Second, a grid-like protrusion is formed on the second side of the blank body. When the aluminum liquid fills into the product cavity and passes through the grooves on the mold, the aluminum liquid will generate a vortex phenomenon in the grooves, thereby clamping the impurities on the surface of the aluminum liquid and part of the gas in the cavity in the groove structure. This reduces the defect rate and impurity rate of the hole types that need to retain the main body part subsequently, thereby improving the internal quality of the product.

[0029] Third, the design of the grid-like protrusions can not only enhance the structural strength of the blank and reduce its own demolding deformation ability before friction welding, but also increase the structural strength during and after friction welding, avoid product damage and reduce the deformation amount, providing many conveniences for the subsequent processes.

[0030] Fourth, place the machining of the allowance cutting after the friction welding step. This is because the operation of friction welding itself may affect the dimensional accuracy of the product. After completing this step, adjusting the dimensions can ensure the product quality. At the same time, removing the additional grid-like protrusions during machining also avoids the addition of extra processes, thereby ensuring production efficiency. Brief Description of the Drawings

[0031] The present invention will be further described in detail below in conjunction with the drawings and preferred embodiments. However, those skilled in the art will appreciate that these drawings are only drawn for the purpose of explaining the preferred embodiments and should not be construed as limiting the scope of the present invention. In addition, unless otherwise specified, the drawings only schematically show the composition or structure of the described object and may include exaggerated displays, and the drawings are not necessarily drawn to scale.

[0032] Figure 1 It is a schematic diagram of an aluminum die-cast battery pack cooling module;

[0033] Figure 2 It is an exploded view of the aluminum die-cast battery pack cooling module;

[0034] Figure 3 It is a schematic diagram of the blank body of the bottom shell in the aluminum die-cast battery pack cooling module;

[0035] Figure 4 It is a schematic diagram of the blank body forming in the aluminum die-cast battery pack cooling module;

[0036] Figure 5 It is a schematic diagram of the edge of the grid-like protrusion in the aluminum die-cast battery pack cooling module;

[0037] Figure 6 It is a schematic diagram of the mechanical shaping of the blank body and the assembled body in the aluminum die-cast battery pack cooling module;

[0038] Figure 7 It is a process flow chart of the processing method of the aluminum die-cast battery pack cooling module.

[0039] Reference numerals: bottom shell 1; aluminum alloy cover plate 2; runner groove 3; runner partition wall 4; water inlet 5; water outlet 6;

[0040] Die p for blank die-casting; groove n; product cavity j; grid-like protrusion 7; edge 71; blank body m; root a; end face b; outer side c; reference plane d; oil cylinder 9. Detailed Description of the Specific Embodiments

[0041] The preferred embodiments of the present invention will be described in detail below with reference to the drawings. Those skilled in the art will appreciate that these descriptions are only descriptive and exemplary and should not be construed as limiting the protection scope of the present invention.

[0042] It should be noted that like reference numerals represent like elements in the following figures. Therefore, once an element is defined in one figure, it will not be further defined or explained in subsequent figures.

[0043] As Figure 1-2 shown, the aluminum die-cast battery pack cooling module includes an aluminum die-cast bottom shell 1 and an aluminum alloy cover plate 2. The first side of the bottom shell 1 has a runner groove 3 with an upward opening, and a runner partition wall 4 is provided in the runner groove 3. The side of the bottom shell 1 has a water inlet 5 and a water outlet 6 communicating with the runner groove. The aluminum alloy cover plate 2 is disposed on the bottom shell 1 and closes the runner groove 3.

[0044] As Figure 7 shown, in this embodiment, a processing method of an aluminum die-cast battery pack cooling module includes the following steps:

[0045] Step A: As Figure 3 shown, prepare a blank body m of the bottom shell by aluminum die-casting process. The second side of the blank body has a grid-like protrusion 7.

[0046] Step B: Prepare the aluminum alloy cover plate.

[0047] Step C: Place the aluminum alloy cover plate on the first side of the blank body.

[0048] Step D: Use friction welding to weld and encapsulate the aluminum alloy cover plate and the blank body to form an assembly.

[0049] Step E: Machine the assembly, adjust the dimensions by machining allowance and remove the grid-like protrusion.

[0050] Step F: Perform surface insulation treatment on the machined assembly.

[0051] The cooling module of this embodiment adopts the technology combining integrated aluminum die-casting and friction welding, reducing the traditional multi-part welding and assembly combination to the welding combination of two main parts. This design eliminates complex assembly processes and the required fasteners and seals, greatly simplifies the production process, and reduces the manufacturing cost. Friction welding is a solid-state joining process that realizes the connection between metals through frictional heat generation and pressure. Compared with traditional bolt connections or seal ring seals, friction welding has higher sealing performance and reliability, effectively solving the problem of leakage caused by seal ring aging in traditional processes. At the same time, compared with the traditional extrusion molding process, it is also more convenient to form a more complex runner structure, avoiding being limited to the design of linear runners.

[0052] Preferably, the friction welding process parameters in step D are: rotational speed 1250 - 1900 rpm, axial pressure 2.5 - 5.0 KN, friction diameter 12 mm, friction time 845 - 855 seconds, upsetting pressure 2.5 - 5.0 KN. Such welding parameters can avoid thermal deformation of the product as much as possible while ensuring the welding strength, and are the optimal choice for welding the aluminum die-cast battery pack cooling module bottom shell and the aluminum alloy cover plate.

[0053] Further preferably, the friction welding process is divided into an initial friction stage with a low rotational speed and a final forging stage with a high rotational speed. By using a gradient rotational speed, the influence of heat input on the microstructure of the weld seam is reduced, ensuring grain refinement in the weld seam area and improving the fatigue resistance.

[0054] For aluminum die-cast products, it is a relatively conventional technical means to adjust the dimensions and trim the burrs through machining. In this step, after removing the dense layer on the surface of the blank, internal defects such as pores are likely to be exposed on the surface, thus affecting the surface performance of the product.

[0055] As Figure 3-4 shown, in this embodiment, special treatment is carried out on the functional surface with high requirements for surface performance of the blank body, so that it can meet the surface performance requirements of subsequent processes after machining. In step A, crossed grooves n are arranged on the mold p for blank die-casting to form a grid-like protrusion 7 on the second side of the blank body. When the aluminum liquid fills the product cavity j and passes through the grooves n on the mold, the aluminum liquid will generate a vortex phenomenon in the grooves, thereby clamping the impurities on the surface of the aluminum liquid and part of the gas in the cavity in the groove structure. This reduces the defect rate and impurity rate of the hole types that need to retain the main body part subsequently, thereby improving the internal quality of the product.

[0056] And placing the machining of allowance cutting after the friction welding step is because the operation of friction welding itself may affect the dimensional accuracy of the product. After completing this step, adjusting the dimensions can ensure the product quality. At the same time, removing the additional grid-like protrusions during machining also avoids the increase of additional processes, thereby ensuring the production efficiency.

[0057] Due to the design of the grid-like protrusions, not only the surface quality of the second side corresponding to the grid-like protrusions has been significantly improved, but also the porosity of the entire die-cast part has been reduced because the die-casting gas has an additional escape channel. Therefore, after removing these structures by CNC machining, the surface quality of each surface, especially the second side of the bottom shell, has been greatly improved, thus avoiding pinhole defects in subsequent insulation treatment and affecting the insulation qualification rate.

[0058] Moreover, this grid-like protrusion design has another advantage. Due to the characteristics of the friction welding process itself, the product will undergo shrinkage deformation after welding and cooling. The grid-like protrusion design can not only enhance the blank structure strength before friction welding to reduce the deformation degree during its own demolding, but also increase the structure strength during and after friction welding, avoid product damage and reduce the deformation amount, providing many conveniences for subsequent processes.

[0059] Preferably, as Figure 3 shown, the grid-like protrusions are uniform diamond-shaped grids. As Figure 5 shown, the edge 71 of the grid-like protrusion gradually decreases in width from the root a to the end face b, and the end face is a plane. The edge height of the grid-like protrusion is 0.3 mm - 0.5 mm. This design detail plays a crucial role in the smoothness of the die-casting process and the uniformity of the product. The design of the gradually decreasing edge width of the grid-like protrusion from the root to the end face forms a certain inclination angle between its outer side c and the reference plane d. This inclined state greatly promotes the more smooth entry of gas into the interior of the grid-like protrusion during die-casting. As shown in the figure, when the aluminum liquid fills the product cavity, the aluminum liquid is injected horizontally, and its main filling direction is consistent with the reference plane. The inclined and transitional grid-like protrusions can effectively guide gas and impurities into its structure interior, thus forming more gas escape channels inside the die-cast part. This design feature not only significantly reduces the porosity of the die-cast part, but also greatly improves the internal quality of the product.

[0060] The aluminum alloy cover plate is usually a flat component and can be made of aluminum alloy sheet. In a preferred embodiment for those with special structures, in step B, the aluminum alloy cover plate is prepared by an extrusion molding process, so that some flow disturbance structures can be set on the aluminum alloy cover plate, thereby improving the heat dissipation effect.

[0061] During the processing of die-cast parts, surface insulation treatment is a crucial step. In step F, the surface insulation treatment is prepared by electrophoresis or powder spraying process. To improve the insulation performance and appearance quality of die-cast parts, preferably, the powder spraying process is used for surface insulation treatment. This process specifically includes the following steps:

[0062] Step F1: High-temperature baking pretreatment: The die-cast part is subjected to high-temperature baking to effectively discharge the gas inside the surface pores. This step is crucial as it can ensure the tight bonding of the subsequent coating to the die-cast part substrate and avoid the coating from showing bubbles or peeling.

[0063] Step F2: Primer powder spraying to form a sealing layer: A layer of primer powder is sprayed on the surface of the die-cast part. This layer of primer powder can quickly cure and form a uniform sealing layer on the surface of the die-cast part. The main function of the sealing layer is to prevent harmful substances such as moisture and humidity from penetrating into the interior of the die-cast part, thereby further improving its insulation performance.

[0064] Step F3: Flour spraying for surface treatment: Conduct flour spraying operation on the surface of die-castings. The flour layer can not only provide the required insulation performance for die-castings but also endow them with good appearance texture. By precisely controlling the spraying thickness and uniformity, we ensure that the surface insulation treatment of each die-casting can achieve the best effect.

[0065] In this embodiment, to ensure the quality of the blank body, before performing the key step D, a leveling treatment process is preferably added. This leveling treatment includes two key links: a primary mechanical shaping treatment and a subsequent heat treatment annealing process. First, the blank body undergoes a primary mechanical shaping treatment to preliminarily adjust its shape and flatness, laying a solid foundation for subsequent processing. Secondly, the blank body enters the heat treatment stage for annealing treatment. The annealing temperature is precisely controlled between 255 - 265 °C. The selection of this temperature range is crucial as it can effectively remove the internal stress generated in the previous processing of the blank body and avoid a decline in material properties due to excessive temperature. Through the annealing treatment, the microstructure of the blank body is optimized, the internal stress is removed, and its overall flatness and stability are further improved.

[0066] Due to the characteristics of the friction welding process itself, the product will undergo shrinkage deformation after welding and cooling, thus affecting the product size. Therefore, before step E, the assembled body after welding in step D is subjected to a secondary mechanical shaping treatment to control the overall flatness.

[0067] As Figure 6 shown, the methods of primary mechanical shaping and secondary mechanical shaping are as follows: First, use the oil cylinder 9 to fix both ends of the product, and then apply an upward force in the opposite direction of the reverse bow at the middle position of the push cylinder to make the structure deform upward. Maintain this state for 30 s to fully shape the product. Finally, retract the push cylinder in sequence, release the oil cylinders on both sides, and the product returns to the free state, undergoing plastic deformation so that the product is adjusted from the bent state to the straight state. Through the above primary and secondary mechanical shaping treatments, we can effectively control the overall flatness of the assembled body and ensure that the product can still maintain the ideal size and shape after welding and cooling.

[0068] The processing method of an aluminum die-cast battery pack cooling module provided by the present invention is introduced. In this article, specific examples are used to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the present invention and its core idea. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements and modifications can still be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A method for processing an aluminum die-casting battery pack cooling module, characterized in that: The aluminum die-cast battery pack cooling module comprises an aluminum die-cast bottom shell and an aluminum alloy cover plate; the first side of the bottom shell has a flow channel groove with an upper opening, the flow channel groove has a flow channel partition wall, and the side of the bottom shell has a water inlet and a water outlet connected to the flow channel groove; the aluminum alloy cover plate is arranged on the bottom shell and closes the flow channel groove; The processing method comprises the following steps: Step A: preparing a blank body of the bottom shell by an aluminum die-casting process, wherein the second side surface of the blank body has a grid-shaped protrusion; Step B: preparing the aluminum alloy cover plate; Step C: placing the aluminum alloy cover plate on the first side surface of the blank body; Step D: using friction welding to weld and package the aluminum alloy cover plate and the blank to form an assembly; Step E: machining the assembly to adjust the size and remove the grid-like protrusions by excess cutting; Step F: performing surface insulation treatment on the machined assembly.

2. The method for processing an aluminum die-casting battery pack cooling module according to claim 1, characterized in that: The aluminum alloy cover plate described in step B is prepared by an extrusion molding process.

3. The method for processing an aluminum die-casting battery pack cooling module according to claim 1, characterized in that: In step F, the surface insulation treatment is prepared by electrophoresis or powder spraying process.

4. The method for processing an aluminum die-casting battery pack cooling module according to claim 1, characterized in that: The grid-shaped protrusions are uniform diamond-shaped grids.

5. The method for processing an aluminum die-casting battery pack cooling module according to claim 1, characterized in that: The width of the edges of the grid-shaped protrusions gradually decreases from the root to the end surface, and the end surface is a plane.

6. The method for processing an aluminum die-casting battery pack cooling module according to claim 1, characterized in that: The edge height of the grid-like protrusions is 0.3mm-0.5mm.

7. The method for processing an aluminum die-casting battery pack cooling module according to claim 1, characterized in that: Step F is prepared by a powder spraying process, and the step F comprises the following sub-steps: Step F1: Bake to discharge the gas in the surface pores; Step F2: Spray a layer of primer on the surface to form a closed layer; Step F3: Spray flour to complete the surface treatment.

8. The method for processing an aluminum die-casting battery pack cooling module according to claim 1, characterized in that: Before step D, the blank is subjected to a flattening treatment, wherein the flattening treatment includes a mechanical shaping treatment and a heat treatment annealing process in sequence, and the annealing temperature is controlled at 255-265°C.

9. The method for processing an aluminum die-casting battery pack cooling module according to claim 8, characterized in that: Before step E, the assembly welded in step D is subjected to secondary mechanical shaping.

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