Battery pack side beam structure for reducing sand hole defects and die-casting die

Abstract

The battery pack side beam structure for reducing the sand hole defect comprises a side beam, a connecting face is arranged on one side of the side beam, a plurality of threaded connecting columns are arranged on the connecting face, the threaded connecting columns protrude outwards, and protruding structures are arranged at the roots of the threaded connecting columns. Compared with the prior art, the battery pack side beam structure for reducing the sand hole defect has the advantages that the protruding structure is arranged at the root of the threaded connecting column, the speed of filling the threaded connecting column with molten metal can be reduced during die-casting forming, the molten metal can flow stably, sand holes in the threaded connecting column are reduced, and the service life of the battery pack side beam structure is prolonged. And the mechanical performance of the threaded connection column is improved. In addition, the invention further provides a die-casting die which is used for die-casting forming of the battery pack side beam structure used for reducing the sand hole defects, the die-casting die is provided with a slag ladle structure to store part of gas in molten metal, and therefore the generation of the sand hole defects in the threaded connection column after die-casting forming is further reduced.

Description

Technical Field

[0001] The present invention relates to the field of die-casting technology, and in particular to a battery pack side beam structure and a die-casting mold for reducing sand hole defects. Background Art

[0002] Die casting is a metal casting process characterized by applying high pressure to the molten metal through the mold cavity. The mold is usually made of a stronger alloy, and the process is somewhat similar to injection molding. Most die castings are iron-free, such as zinc, copper, aluminum, magnesium, lead, tin, lead-tin alloys and their alloys. The workpieces formed by die casting have high dimensional accuracy and structural strength, and excellent mechanical properties.

[0003] The side beams of the battery packs of new energy vehicles are usually made of aluminum alloy die-casting. The common aluminum alloy die-casting process is as follows: first, select appropriate raw materials, such as aluminum alloy, and send them to the smelting furnace for smelting and degassing to obtain pure molten metal; then pour the molten metal into the mold, use high pressure to quickly fill the molten metal into the mold cavity, so that the molten metal fully flows and fills the entire mold cavity; finally, under high pressure, the molten metal gradually cools and solidifies to form the required battery pack side beam shape. After the casting is fully formed, a series of post-processing steps are required, including removing excess material handles, removing burrs, grinding the outer surface, and performing outer surface treatment to improve the appearance and performance of the casting. However, since the molten metal is quickly filled under high pressure, the flow state of the molten metal is unstable, so the final casting is very prone to sand holes (holes formed on the surface or inside of the casting due to gas or impurities, etc.). For the side beams of the battery pack, the protruding length of the threaded connection column is often 3 times the thickness of the side beam wall, so exhaust is more difficult. Therefore, there are a lot of sand holes on the threaded connection column. Therefore, when the battery pack side beam is connected to the battery pack shell, the mechanical properties of the threaded connection column will decrease and cannot meet the quality requirements of some customers. Therefore, it is necessary to design a battery pack side beam structure and a die-casting mold for reducing sand hole defects to solve the above problem. Summary of the invention

[0004] An object of the present invention is to provide a battery pack side beam structure for reducing sand hole defects, which has fewer sand hole defects on the threaded connecting column during die casting and good mechanical properties.

[0005] In order to achieve the above-mentioned purpose, the battery pack side beam structure for reducing sand hole defects provided by the present invention includes a side beam, a connecting surface is provided on one side of the side beam, a plurality of threaded connecting columns are provided on the connecting surface, the threaded connecting columns protrude outward from the connecting surface, and a protruding structure is provided at the root of the threaded connecting column.

[0006] Compared with the prior art, the battery pack side beam structure for reducing sand hole defects provided by the present invention can increase the flow channel of the molten metal at the root of the threaded connection column during die casting to further guide the flow of the molten metal, reduce the speed of the molten metal filling the threaded connection column, and make the molten metal flow smoothly, thereby reducing the generation of sand holes on the threaded connection column, so that the threaded connection column has good mechanical properties. In addition, the presence of the convex structure can also improve the stability of the mold during die casting, thereby improving production efficiency and facilitating mass production.

[0007] Specifically, the height of the protruding structure gradually decreases from the root of the threaded connection column to the edge of the connection surface. Such a configuration facilitates demoulding after die-casting.

[0008] Specifically, the height of the protruding structure is less than the height of the threaded connection column, and the height of the protruding structure is 5 mm to 10 mm. Such a setting can reasonably reduce the injection force exerted on the molten metal when filling and forming the threaded connection column, reduce air entrainment, and further reduce the generation of sand hole defects on the threaded connection column.

[0009] Another object of the present invention is to provide a die-casting mold, which is used for die-casting the aforementioned battery pack side beam structure for reducing sand hole defects, and the die-casting mold includes a cavity and a pouring system; the cavity is used to form the battery pack side beam structure for reducing sand hole defects; the pouring system is connected to the cavity and is used to fill the cavity with molten metal; the cavity includes a plurality of pillow structures for forming the protruding structure and a plurality of recessed structures for forming the threaded connecting column; the pouring system includes a slag bag structure, and the slag bag structure is connected to the end of the recessed structure.

[0010] Compared with the prior art, the die-casting mold provided by the present invention sets the recessed structure in the mold cavity to die-cast the threaded connecting column, and sets the pillow structure to die-cast the protruding structure, so that the pillow structure becomes a part of the casting system to guide the flow of the molten metal flowing into the recessed structure, thereby reducing the flow rate of the molten metal at the recessed structure, making the molten metal flow smoothly, avoiding the molten metal from entraining a large amount of gas due to unstable flow, and reducing the sand hole defects of the threaded connecting column after die-casting; in addition, the slag bag structure of the die-casting mold is connected to the end of the recessed structure, which can reduce the inclusions in the molten metal while accommodating the gas in the molten metal used to form the threaded connecting column, thereby further reducing the generation of sand hole defects on the threaded connecting column after die-casting.

[0011] Specifically, the pouring system further includes a plurality of overflow troughs, which are arranged on both sides of the mold cavity and are connected to the mold cavity. Such an arrangement can assist in venting the mold cavity to reduce the generation of sand hole defects and collect excess molten metal to reduce material waste.

[0012] Specifically, the pouring system further includes a sprue and a runner, and the runner is arranged between the sprue and the cavity to connect the sprue with the cavity.

[0013] Specifically, the sprue and the runner are both arranged on the side of the cavity, which facilitates the removal of the water inlet of the casting after demoulding.

[0014] Specifically, the sprue is in a tapered shape that is smaller at the top and larger at the bottom, and the cross-section of the runner is a trapezoid.

[0015] Specifically, the runner includes a main runner and a branch runner, and the latter two are connected in sequence; the cross-sectional area of ​​the main runner is larger than the cross-sectional area of ​​the branch runner. Such a setting makes the mold opening process relatively easy and reduces production costs.

[0016] Specifically, the branch runner extends from the end of the main runner along the length direction of the cavity to the edges of both ends of the cavity. This arrangement allows the molten metal to be divided into multiple streams and enter the cavity at the same time to reduce the time difference of the molten metal filling in the length direction parallel to the cavity, thereby reducing the occurrence of die casting defects. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is an angled stereoscopic view of the battery pack side beam structure for reducing sand hole defects of the present invention.

[0018] Figure 2 It is a stereoscopic view from another angle of the battery pack side beam structure for reducing sand hole defects of the present invention.

[0019] Figure 3 It is a three-dimensional simulation diagram of the pouring system of the die-casting mold of the present invention and the cavity after being filled with entities, showing the connection relationship between the pouring system and the cavity.

[0020] Figure 4 The top view of the three-dimensional simulation diagram of the pouring system of the die-casting mold of the present invention and the cavity after being filled with a solid body shows the overflow grooves arranged on both sides of the cavity by the pouring system.

[0021] Figure 5 It is a schematic cross-sectional view of a main runner of a pouring system of a die-casting mold of the present invention.

[0022] Figure 6It is a schematic cross-sectional view of a branch runner of a pouring system of a die-casting mold of the present invention.

[0023] Figure 7 This is an X-ray inspection image of a battery pack side beam structure for reducing sand hole defects obtained by using the die-casting mold of the present invention. DETAILED DESCRIPTION

[0024] The following is a clear and complete description of the technical solutions in the embodiments of the present application in combination with the specific embodiments and the accompanying drawings, and an explanation of the technical solutions of the present invention. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments.

[0025] See also Figure 1 and Figure 2 The battery pack side beam structure 100 for reducing sand hole defects provided by the present invention includes a side beam 1, and a connecting surface 10 is provided on one side of the side beam 1. A plurality of threaded connecting columns 11 are provided on the connecting surface 10, and the threaded columns 11 are used to connect with the battery pack shell. The threaded connecting column 11 protrudes outward from the connecting surface 10, and a protruding structure 2 is provided at the root of the threaded connecting column 11. Specifically, the height of the protruding structure 2 gradually decreases from the root of the threaded connecting column 11 to the edge of the connecting surface 10, thereby forming an inclined structure. Such an arrangement facilitates demolding after die-casting. In addition, the inclined arrangement of the protruding structure 2 can further provide support to the root of the threaded connecting column 11, thereby reducing the deformation of the threaded connecting column 11. In this embodiment, the battery pack side beam structure 100 for reducing sand hole defects is made of aluminum alloy material.

[0026] Further, see Figure 2 , the height of the protruding structure 2 is less than the height of the threaded connection column 11, and the height of the protruding structure 2 is 5 mm-10 mm. Such a setting can reasonably reduce the injection force of the molten metal when filling and forming the threaded connection column 11, reduce air entrainment, and further reduce the generation of sand hole defects on the threaded connection column 11. In addition, the presence of the protruding structure 2 can also improve the stability of the mold during die casting, thereby improving production efficiency and facilitating mass production.

[0027] See also Figure 3 and Figure 4The die-casting mold provided by the present invention is used to manufacture the battery pack side beam structure 100 for reducing sand hole defects. The die-casting mold includes a cavity 200 and a pouring system 300; the cavity 200 is used to form the battery pack side beam structure 100 for reducing sand hole defects; the pouring system 300 is connected to the cavity 200 and is used to fill the cavity 200 with molten metal; the cavity 200 includes a plurality of pillow structures 210 for forming the protruding structure 2 and a plurality of recessed structures 220 for forming the threaded connecting column 11. Figure 3 and Figure 4 In the figure, the pouring system 300 and the cavity 200 are both simulation diagrams after filling the solid body. At this time, the shape of the cavity 200 is the same as the shape of the battery pack side beam structure 100 for reducing sand hole defects. Figure 3 and Figure 4 In the embodiment, the recessed structure 220 is convex, and the pillow structure 210 is also convex. The pouring system 300 includes a slag bag structure 310, and the slag bag structure 310 is connected to the end of the recessed structure 220. Such a configuration can reduce metal inclusions while accommodating the gas carried by the molten metal, thereby further reducing the generation of sand hole defects on the threaded connection column 11 after die casting.

[0028] Further, see Figure 3 and Figure 4 , the pouring system 300 also includes a plurality of overflow grooves 320, and the overflow grooves 320 are arranged on both sides of the cavity 200 and the overflow grooves 320 are connected to the cavity 200. Specifically, the overflow grooves 320 are connected to the bottom of the cavity 200, and are respectively located on the sides of the two long sides of the bottom of the cavity 200. The presence of the overflow grooves 320 can assist in venting the cavity 200 to reduce the generation of sand hole defects and collect excess molten metal to reduce material waste. In this embodiment, the total volume of the overflow grooves 320 is 20% of the battery pack side beam structure 100 for reducing sand hole defects.

[0029] For further information, see Figures 3 to 6, the pouring system 300 further includes a sprue 330, a runner 340 and an ingode 350. The sprue 330 is used to receive molten metal, the runner 340 is disposed between the sprue 330 and the ingode 350 to distribute the molten metal in the sprue 330 to the ingode 350, and the sprue 330 and the runner 340 are both disposed on the side of the cavity 200 to facilitate the removal of the water inlet after die casting, the ingode 350 is connected to the end of the runner 340 and communicated with the cavity 200, and is used to guide the molten metal into the cavity 200. Specifically, the runner 340 includes a main runner 341 and a branch runner 342. During die casting, the molten metal flows through the main runner 341 and the branch runner 343 in sequence, and the cross-sectional area of ​​the main runner 341 is greater than the cross-sectional area of ​​the branch runner 342. In this embodiment, the sprue 330 is located in the middle of the long side of the top of the cavity 200, and the number of the main runners 341 is two, and they extend from the middle of the long side of the top of the cavity 200 to the edge positions of the two ends of the long side, and each of the main runners 341 is connected to a plurality of branch runners 342, thereby forming a comb-like structure. Specifically, each of the main runners 341 is connected to fifteen branch runners 342. Such a setting enables the molten metal to be divided into multiple strands and enter the cavity 200 at the same time to reduce the time difference of the molten metal filling in the length direction parallel to the cavity 200, thereby reducing the generation of die casting defects. In addition, in order to simplify the manufacturing process of the die casting mold and reduce the production cost, the cross-sectional shape of the runner 340 is a trapezoid. Since the battery pack side beam structure 100 for reducing sand hole defects is made of aluminum alloy, the sprue 330 is configured to be a cone with a small top and a large bottom suitable for aluminum and magnesium alloy die casting.

[0030] The following is a description of the specific working principle of the die-casting mold provided by the present invention. During die-casting, the molten metal liquid, under the action of external pressure, successively enters the mold cavity 200 through the straight runner 330, the main runner 341, the branch runner 342 and the inner runner 350 and gradually fills the mold cavity 200. When the metal liquid is filling the recessed structure 220 for forming the threaded connecting column 11, the metal liquid will simultaneously fill the pillow structure 210 for forming the protruding structure 2. The flowing metal liquid will be divided into two streams here, and the flow speed of the metal liquid will be reduced, and the flow will be smoother, which avoids the metal liquid from entraining a large amount of gas in the process of filling the recessed structure 220 due to excessive flow rate, thereby reducing the generation of sand hole defects in the threaded connecting column 11. In addition, since the slag bag structure 310 is connected to the end of the recessed structure 220, when the molten metal fills the recessed structure 220, part of the gas in the molten metal can also be stored in the slag bag structure 310, thereby further reducing the generation of sand hole defects in the threaded connection column 11. When the molten metal solidifies and forms, the die casting process is completed. The casting is taken out and the excess water outlet is removed, and then polished to obtain the battery pack side beam structure 100 for reducing sand hole defects. Please refer to Figure 7 , after X-ray inspection, it was found that the threaded connecting column 11 of the battery pack side beam structure 100 for reducing sand hole defects obtained by using the die-casting mold of the present invention has very few sand hole defects, which can meet the quality requirements of customers.

[0031] Compared with the prior art, the die-casting mold provided by the present invention is provided with the recessed structure 220 in the cavity 200 to die-cast the threaded connection column 11, and the pillow structure 210 is provided to die-cast the protruding structure 2, so that the pillow structure 210 becomes a part of the pouring system 300 to guide the flow of the molten metal flowing into the recessed structure 220, reduces the flow rate of the molten metal at the recessed structure 220, makes the molten metal flow smoothly, and avoids the molten metal from entraining a large amount of gas due to unstable flow, thereby reducing the sand hole defects of the threaded connection column 11 after die-casting. In addition, the slag bag structure 310 of the die-casting mold is connected to the end of the recessed structure 220, which can accommodate the gas in the molten metal used to form the threaded connection column 11 while reducing the inclusions in the molten metal, thereby further reducing the generation of sand hole defects on the threaded connection column 11 after die-casting, and improving the mechanical properties of the threaded connection column 11 to meet the quality requirements of customers.

[0032] The above disclosure is only the preferred embodiment of the present invention. The above embodiments of the present invention are only examples for clearly illustrating the present invention, and are not limitations on the embodiments of the present invention. For ordinary technicians in the field, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention and still fall within the scope covered by the present invention.

Claims

1. A battery pack side beam structure for reducing sand hole defects, characterized in that: It comprises a side beam, one side of which is provided with a connection surface, the connection surface is provided with a plurality of threaded connection columns, the threaded connection columns protrude outward from the connection surface, and the roots of the threaded connection columns are provided with a protruding structure.

2. The battery pack side beam structure for reducing sand hole defects according to claim 1, characterized in that: The height of the protruding structure gradually decreases from the root of the threaded connection column to the edge of the connection surface.

3. The battery pack side beam structure for reducing sand hole defects according to claim 1, characterized in that: The height of the protruding structure is smaller than the height of the threaded connection column, and the height of the protruding structure is 5 mm-10 mm.

4. A die-casting mold for die-casting a battery pack side beam structure for reducing sand hole defects as described in any one of claims 1 to 3, characterized in that: It includes a pouring system and a cavity; the pouring system is connected to the cavity and is used to fill the cavity with molten metal; the cavity includes a plurality of pillow structures for forming the protruding structure and a plurality of recessed structures for forming the threaded connecting column; the pouring system includes a slag bag structure, and the slag bag structure is connected to the end of the recessed structure.

5. The die-casting mold according to claim 4, characterized in that: The pouring system further comprises a plurality of overflow grooves, wherein the overflow grooves are arranged on both sides of the mold cavity and the overflow grooves are communicated with the mold cavity.

6. The die-casting mold according to claim 4, characterized in that: The pouring system further includes a sprue and a runner, wherein the runner is arranged between the sprue and the cavity so that the sprue is connected with the cavity.

7. The die-casting mold according to claim 6, characterized in that: The sprue and the runner are both arranged on the side of the cavity.

8. The die casting mold according to claim 6, characterized in that: The sprue is in a tapered shape with a small top and a large bottom, and the cross-section of the runner is a trapezoid.

9. The die casting mold according to claim 6, characterized in that: The runner includes a main runner and a branch runner, and the latter two are connected in sequence; the cross-sectional area of ​​the main runner is larger than the cross-sectional area of ​​the branch runner.

10. The die casting mold according to claim 9, characterized in that: The branch runner extends from the end of the main runner to the edges of both ends of the cavity along the length direction of the cavity.

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