Extrusion molding device of battery shell and battery shell

Abstract

The utility model provides an extrusion molding device of a battery shell and the battery shell. The extrusion molding device comprises an extrusion die and a heating piece, the extrusion die comprises an extrusion outer die and an extrusion inner die, and a battery shell forming space for curing a steel melt is formed between the extrusion outer die and the extrusion inner die; a containing cavity is formed in at least one of the extrusion outer die and the extrusion inner die, the heating piece is arranged in the containing cavity, and the working temperature of the heating piece is lower than the melting point of a steel melt. The battery shell made of the steel is processed in an extrusion molding manner, so that the problem of low local strength caused by incapability of molding and welding due to high-depth drawing can be avoided. And the integral forming of the battery shell can be realized at one time in an extrusion forming mode, the requirement on a forming technology is not high, and the quality of the battery shell can be ensured. The heating piece can prevent the steel melt in the space formed by the battery shell from being cooled too fast, so that the material distribution of the battery shell is more uniform, and the mechanical property is more balanced.

Description

Technical Field

[0001] This utility model relates to the field of power battery technology, and in particular to an extrusion molding apparatus for a battery casing and a battery casing. Background Technology

[0002] Because traditional deep drawing processes cannot meet the requirements for deep forming of stainless steel square battery casings, multiple bending / roll bending followed by welding is currently used to process and form stainless steel square battery casings. However, welding inevitably results in weld seams, which leads to lower strength in the welded area of ​​the casing and a higher risk of cracking. Utility Model Content

[0003] The technical problem to be solved by this utility model is to overcome the defects of the existing technology that uses welding to form stainless steel square battery casings, resulting in low local strength and easy breakage of the casing. The present invention provides an extrusion molding device for battery casings and a battery casing.

[0004] The present invention solves the above-mentioned technical problems through the following technical solution:

[0005] An extrusion molding apparatus for a battery casing, the extrusion molding apparatus for the battery casing comprising an extrusion die and a heating element;

[0006] The extrusion die includes an outer extrusion die and an inner extrusion die. The outer extrusion die is sleeved on the outer periphery of the inner extrusion die, and a space for forming a battery casing is formed between the outer extrusion die and the inner extrusion die for the solidification of molten steel.

[0007] At least one of the outer extrusion die and the inner extrusion die has a receiving cavity inside, and the heating element is disposed in the receiving cavity. The working temperature of the heating element is lower than the melting point of the molten steel.

[0008] In this design, the steel battery casing is manufactured using extrusion molding, avoiding the problems of insufficient forming depth in deep drawing and the resulting low local strength due to welding. Extrusion molding allows for the integral forming of the battery casing in a single step, requiring less sophisticated forming technology while ensuring high-quality casing. The heating element prevents the molten steel within the casing from cooling too quickly, resulting in a more uniform material distribution and more balanced mechanical properties.

[0009] Preferably, the receiving cavity includes a first receiving cavity disposed inside the extrusion outer die, and the heating element includes a first heating element disposed within the first receiving cavity;

[0010] The battery casing forming space has multiple side portions along its circumference, and at least one of the first heating elements is provided on the outer periphery of each side portion.

[0011] In this solution, the above-mentioned settings improve the temperature uniformity on the outside of the battery casing forming space, making the material distribution of the battery casing more uniform and the mechanical properties more balanced.

[0012] Preferably, the extrusion molding apparatus for the battery casing further includes a positioning element connected to the extrusion die and extending beyond the extrusion die along the length direction of the space formed by the battery casing.

[0013] In this solution, the positioning component is used to enable quick alignment and installation of the extrusion die and other components, facilitates the assembly of the extrusion molding device, improves the positioning accuracy of the extrusion die, and enhances the extrusion molding effect.

[0014] Preferably, the receiving cavity includes a second receiving cavity disposed inside the extrusion inner die, and the heating element includes a second heating element disposed within the second receiving cavity;

[0015] The positioning member is fixed on the extrusion inner mold, and the positioning member is provided with the second heating element on both sides along the width direction of the space formed by the battery housing.

[0016] In this solution, the above-mentioned settings improve the temperature uniformity inside the space formed by the battery casing, making the material distribution of the battery casing more uniform and the mechanical properties more balanced.

[0017] Preferably, the positioning element is located at the center of the extrusion inner die, and the extrusion inner die is provided with a plurality of second receiving cavities, which are symmetrical with respect to the positioning element.

[0018] In this scheme, the above-mentioned settings further improve the temperature uniformity inside the space formed by the battery casing, making the material distribution of the battery casing more uniform and the mechanical properties more balanced.

[0019] Preferably, the receiving cavity extends through the extrusion die at both ends along the length direction of the battery housing forming space, and the length of the heating element in the length direction of the battery housing forming space is equal to the length of the receiving cavity in the length direction of the battery housing forming space.

[0020] In this solution, the above-mentioned arrangement ensures that the molten steel located at any position along the length of the space forming the battery casing can be effectively kept warm, preventing the molten steel from cooling too quickly in certain areas, and making the material distribution of the battery casing more uniform and the mechanical properties more balanced.

[0021] Preferably, the wall thickness of the space formed by the battery casing is 0.2~1mm.

[0022] In this design, steel has a higher structural strength than aluminum alloy. Therefore, the thickness of a battery casing made of steel can be reduced compared to a traditional aluminum alloy battery casing while maintaining the same structural strength. This allows for more space to be reserved for the battery cells and increases the battery's capacity.

[0023] Preferably, the operating temperature of the heating element is 800~1000℃.

[0024] In this design, the operating temperature of the heating element is controlled within a certain range to prevent it from being too low, which would reduce the heat preservation effect on the molten steel and cause it to cool too quickly. Simultaneously, the operating temperature of the heating element is prevented from being too high, which would affect the solidification of the molten steel and thus reduce its solidification efficiency, thereby improving the molding efficiency of the battery casing.

[0025] Preferably, the heating element is a nickel-chromium resistance heating rod.

[0026] In this design, the nickel-chromium resistance heating rod operates at a high temperature, which provides good insulation for the molten steel, preventing the molten steel in the battery casing from cooling too quickly, resulting in a more uniform material distribution and more balanced mechanical properties in the battery casing.

[0027] A battery casing is formed by an extrusion molding apparatus for battery casings as described above, and the battery casing is made of steel.

[0028] In this solution, the battery casing, made of steel, is processed using extrusion molding, which avoids the problems of insufficient forming depth due to deep drawing and the resulting low local strength caused by welding. Extrusion molding can achieve the overall forming of the battery casing in one step, with low requirements for molding technology and ensuring the quality of the battery casing.

[0029] The significant advantages of this invention are as follows: the battery casing, made of steel, is processed using extrusion molding, which avoids the problems of insufficient forming depth due to deep drawing and the resulting low local strength caused by welding. Extrusion molding allows for the integral forming of the battery casing in a single step, requiring less sophisticated forming technology while ensuring the quality of the battery casing. The heating element prevents the molten steel within the forming space from cooling too quickly, resulting in a more uniform material distribution and more balanced mechanical properties in the battery casing. Attached Figure Description

[0030] Figure 1 This is a three-dimensional structural diagram of an extrusion die according to an embodiment of the present invention.

[0031] Figure 2 This is a three-dimensional structural diagram of a battery casing according to an embodiment of the present invention.

[0032] Figure 3This is a schematic diagram of the internal structure of an extrusion die according to an embodiment of the present invention.

[0033] Explanation of reference numerals in the attached figures:

[0034] Extrusion die 1

[0035] Extrusion outer mold 11

[0036] Extrusion inner mold 12

[0037] Reception cavity 2

[0038] First receiving cavity 21

[0039] Second receiving cavity 22

[0040] Heating element 3

[0041] First heating element 31

[0042] Second heating element 32

[0043] Battery casing 4

[0044] Battery casing forms space 5

[0045] Short side face 51

[0046] Long side 52

[0047] Positioning component 6

[0048] Fixing hole 7 Detailed Implementation

[0049] The present invention will be described more clearly and completely below with reference to the accompanying drawings, using a preferred embodiment.

[0050] like Figure 1 As shown, this embodiment discloses an extrusion molding system for manufacturing by extrusion molding. Figure 2 Battery casing 4.

[0051] Specifically, in this embodiment, the battery casing 4 is made of steel, and the molten steel in the molten state is extruded into the shape of the battery casing 4 under the extrusion molding system.

[0052] In this embodiment, the steel used for the battery casing 4 is stainless steel, such as SUS304 or SUS316L. Stainless steel is more corrosion-resistant, which can improve the service life of the battery casing 4. Moreover, the strength and hardness of steel are greater than those of aluminum alloy. The battery casing 4 made of steel can be thinner than the traditional aluminum alloy battery casing 4 while maintaining the same structural strength, leaving more installation space for the battery cells and increasing the battery's capacity.

[0053] The following uses SUS304 stainless steel and 3003H14 aluminum as examples to illustrate the difference in strength between the two materials: SUS304 stainless steel has a yield strength of approximately 205-515 MPa, and its compressive strength is above 3 MPa, assuming the battery casing 4 does not fail. 3003H14 aluminum has a yield strength of approximately 140-185 MPa, and its compressive strength is above 1.3 MPa, assuming the battery casing 4 does not fail. Therefore, it is evident that SUS304 stainless steel has superior yield strength and compressive strength compared to 3003H14 aluminum.

[0054] Therefore, the battery casing 4, made of steel, is more resistant to high temperatures, can withstand greater pressure, is less prone to severe burn-through, and reduces the risk of thermal diffusion of the battery cell.

[0055] In other alternative embodiments, the battery casing 4 may also be made of steel other than stainless steel.

[0056] The extrusion molding system includes a heating device, an extruder, an extrusion molding unit for the battery casing, a cooling device, and a cutting device. The heating device heats the steel raw material, molten it, and the extruder extrudes the molten steel into the extrusion molding unit for the battery casing at a controlled quantity, pressure, and temperature. The molten steel is initially cooled and shaped into the product by the extrusion molding unit. The cooling device further cools the shaped product, and the cutting device cuts the cooled product to the appropriate size.

[0057] like Figure 1 and Figure 3 As shown, the battery casing extrusion molding device includes an extrusion die 1, a heating element 3, and a positioning element 6.

[0058] like Figure 1 and Figure 3 As shown, the extrusion die 1 includes an outer extrusion die 11 and an inner extrusion die 12. The outer extrusion die 11 is fitted around the outer periphery of the inner extrusion die 12. A battery housing forming space 5 is formed between the outer extrusion die 11 and the inner extrusion die 12 for solidifying the steel melt. The battery housing forming space 5 is used to form the shape of the battery housing 4.

[0059] Specifically, such as Figures 1-3 As shown, in this embodiment, the battery casing 4 is square, the outer extrusion mold 11 is cylindrical, the center of the outer extrusion mold 11 has a through hole with a rectangular cross-section, the inner extrusion mold 12 is a cuboid structure, the inner extrusion mold 12 is located in the rectangular through hole of the outer extrusion mold 11, and the outer peripheral surface of the inner extrusion mold 12 and the hole wall of the rectangular through hole form a battery casing forming space 5.

[0060] In other alternative embodiments, the outer extrusion die 11 and the inner extrusion die 12 can be designed into other shapes depending on the product to be produced.

[0061] Furthermore, since steel has a higher structural strength than aluminum alloy, the wall thickness of the battery casing 4 in this embodiment can be designed to be smaller, meaning the wall thickness of the battery casing forming space 5 can be designed to be smaller. In this embodiment, the wall thickness of the battery casing forming space 5 is approximately 0.2~1mm, and the specific thickness can be selected based on the actual product being manufactured.

[0062] Wherein, the wall thickness of the battery casing forming space 5 refers to the thickness of the outer peripheral surface of the extrusion inner mold 12 and the wall of the rectangular through hole along the length of the battery casing forming space 5. Figure 1 (in the X direction) and width direction ( Figure 1 The thickness in the Y direction.

[0063] In this embodiment, the wall thickness of the battery housing forming space 5 is the same everywhere. In other alternative embodiments, the wall thickness at different locations of the battery housing forming space 5 can also be designed to different values ​​according to actual needs.

[0064] In this embodiment, the battery casing 4, made of steel, is processed by extrusion molding, which avoids the problems of insufficient forming at high depths and low local strength caused by welding. Extrusion molding can achieve the overall forming of the battery casing 4 in one step, with low requirements for molding technology and can ensure the quality of the battery casing 4.

[0065] In addition, due to the high strength of steel, the weld lines on the battery casing 4 made of steel are very narrow or even non-existent, further ensuring the strength of the battery casing 4.

[0066] like Figure 1 and Figure 3 As shown, both the outer extrusion die 11 and the inner extrusion die 12 are provided with receiving cavities 2. The heating element 3 is located in the receiving cavity 2, and the working temperature of the heating element 3 is lower than the melting point of the steel melt. The heating element 3 can prevent the steel melt in the battery casing forming space 5 from cooling too quickly, so that the material distribution of the battery casing 4 is more uniform and the mechanical properties are more balanced.

[0067] Specifically, in this embodiment, the heating element 3 is a nickel-chromium resistance heating rod. The nickel-chromium resistance heating rod has a high operating temperature, reaching 1000℃, and its operating temperature is also lower than the melting point of steel (for example, the melting point of SUS304 stainless steel is about 1400~1450℃). It can provide a good heat preservation effect on the molten steel, prevent the molten steel in the battery casing forming space 5 from cooling too quickly, and make the material distribution of the battery casing 4 more uniform and the mechanical properties more balanced.

[0068] In other alternative embodiments, the heating element 3 can be selected from other heating structures, and the operating temperature of the heating element 3 is preferably in the range of 800~1000℃. On the one hand, this prevents the operating temperature of the heating element 3 from being too low, which would reduce the heat preservation effect on the molten steel and cause the molten steel to cool too quickly. On the other hand, it prevents the operating temperature of the heating element 3 from being too high, which would affect the solidification of the molten steel, thereby avoiding a reduction in the solidification efficiency of the molten steel and thus improving the molding efficiency of the battery casing 4.

[0069] like Figure 1 and Figure 3 As shown, the receiving cavity 2 includes a plurality of first receiving cavities 21 disposed inside the outer extrusion mold 11 and a plurality of second receiving cavities 22 disposed inside the inner extrusion mold 12. The heating element 3 includes a first heating element 31 disposed in the first receiving cavity 21 and a second heating element 32 disposed in the second receiving cavity 22. The number of first receiving cavities 21 and the number of first heating elements 31 are the same, and the number of second receiving cavities 22 and the number of second heating elements 32 are the same. Both the first receiving cavity 21 and the second receiving cavity 22 are through-hole structures. The first receiving cavity 21 passes through the outer extrusion mold 11 at both ends along the length direction of the battery housing forming space 5, and the second receiving cavity 22 passes through the inner extrusion mold 12 at both ends along the length direction of the battery housing forming space 5. The length of the first heating element 31 in the length direction of the battery housing forming space 5 is equal to the length of the first receiving cavity 21 in the length direction of the battery housing forming space 5, and the length of the second heating element 32 in the length direction of the battery housing forming space 5 is equal to the length of the second receiving cavity 22 in the length direction of the battery housing forming space 5, so that the molten steel located at any position in the length direction of the battery housing forming space 5 can be effectively kept warm, avoiding localized excessively rapid cooling of the molten steel, and making the material distribution of the battery housing 4 more uniform and the mechanical properties more balanced.

[0070] In other alternative embodiments, the receiving cavity 2 may be provided only inside the outer extrusion die 11 or only inside the inner extrusion die 12. In this embodiment, the receiving cavity 2 is provided inside both the outer extrusion die 11 and the inner extrusion die 12 to improve the heat preservation effect on the molten steel.

[0071] In this embodiment, the outer extrusion die 11 and the inner extrusion die 12 have the same length in the longitudinal direction of the battery housing forming space 5. Therefore, the first receiving cavity 21 and the second receiving cavity 22 also have the same length in the longitudinal direction of the battery housing forming space 5. In other alternative embodiments, the lengths of the first receiving cavity 21 and the second receiving cavity 22 may be different, or the first receiving cavity 21 and / or the second receiving cavity 22 may be a perforated chamber structure closed at one end.

[0072] Furthermore, such as Figures 1-3As shown, since the battery casing 4 in this embodiment is square, the battery casing forming space 5 is also correspondingly square. The battery casing forming space 5 has four side portions along its circumference: two short-side side portions 51 and two long-side side portions 52. The short-side side portions 51 form the side portions in the thickness direction of the battery casing 4, and the long-side side portions 52 form the side portions in the width direction of the battery casing 4. A first heating element 31 is provided on the outer periphery of each of the two short-side side portions 51, and a second heating element 32 is provided on the inner periphery of each of the two short-side side portions 51. Three first heating elements 31 are provided on the outer periphery of each of the two long-side side portions 52, and the three first heating elements 31 are spaced apart along the width direction of the battery casing forming space 5.

[0073] In this embodiment, multiple heating elements 3 are provided at multiple locations on the outer and inner periphery of the battery housing forming space 5 to improve the temperature uniformity on the outside of the battery housing forming space 5, making the material distribution of the battery housing 4 more uniform and the mechanical properties more balanced.

[0074] In other alternative implementations, the number of first heating elements 31 corresponding to each side portion can be designed to be different, but at least one, to ensure temperature uniformity.

[0075] Furthermore, such as Figure 1 and Figure 3 As shown, the positioning element 6 is connected to the extrusion die 1 and extends beyond the extrusion die 1 along the length direction of the space 5 formed by the battery casing. The positioning element 6 is used to realize the quick alignment and installation of the extrusion die 1 and other components in the extrusion molding system, facilitate the assembly of the extrusion molding device, improve the positioning accuracy of the extrusion die 1, and improve the extrusion molding effect.

[0076] Specifically, such as Figure 1 and Figure 3 As shown, the extrusion inner die 12 is provided with fixing holes 7 that extend through both ends in the length direction of the battery housing forming space 5. The positioning member 6 is a positioning rod, which passes through the fixing holes 7 and is fixed to the extrusion inner die 12. The two ends of the positioning rod extend out of the extrusion inner die 12 in the axial direction for cooperation with other components.

[0077] In other alternative embodiments, the positioning element 6 may also adopt other structural forms, as long as it can achieve the positioning of the extrusion die 1 and other components.

[0078] Furthermore, such as Figure 1 As shown, the positioning member 6 is provided with a second heating member 32 on both sides along the width direction of the battery housing forming space 5, so as to improve the temperature uniformity inside the battery housing forming space 5, and make the material distribution of the battery housing 4 more uniform and the mechanical properties more balanced.

[0079] In this embodiment, the positioning member 6 is located at the center of the extrusion inner mold 12. The two second receiving cavities 22 on the extrusion inner mold 12 are symmetrical with respect to the positioning member 6 in the width direction of the battery housing forming space 5. That is, the number of second heating members 32 on both sides of the positioning member 6 is the same and they are symmetrically arranged, so as to further improve the uniformity of the temperature inside the battery housing forming space 5, and make the material distribution of the battery housing 4 more uniform and the mechanical properties more balanced.

[0080] In other alternative embodiments, the number of second heating elements 32 on both sides of the positioning element 6 may be different or asymmetrical, and can be set according to the actual situation.

[0081] The following is a brief description of the extrusion molding process of the battery casing 4:

[0082] The first step is to prepare the steel raw materials. These raw materials are usually provided in the form of solid profiles or bars.

[0083] The second step is heating and pre-treating the steel raw materials. The steel raw materials are heated to a suitable temperature using a heating device to bring them into a plastic state. During the heating process, the steel raw materials can also be pre-treated, such as deoxidizing and removing impurities, to improve the quality and performance of the material.

[0084] The third step is extruding the steel raw material. The heated steel raw material is placed into the hopper of the extruder, and propelled into the extrusion barrel by the rotation and propulsion of the screw. In the extrusion barrel, the steel raw material is heated and compressed to form a plastic steel melt.

[0085] The fourth step is to form the product shape. The molten steel is propelled into the extrusion head of the extruder by the screw and pushed into the extrusion die 1 connected to the extrusion head to form the final shape of the product. In the extrusion head, the molten steel is squeezed through the battery casing space 5 of the extrusion die 1 to form a continuous billet or profile.

[0086] The fifth step is cooling and curing the product. After the extruded billet or profile passes through the extrusion die 1, it enters the cooling zone, where the steel battery casing 4 is rapidly cooled and cured by a cooling device.

[0087] Step 6: Cutting and processing the product. The cooled and solidified blank or profile is cut using a cutting device to obtain the required length of the battery casing 4. Further processing and treatment can be performed according to product requirements, such as cold working, heat treatment, and surface treatment.

[0088] In the description of this utility model, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship of the device or component shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0089] While specific embodiments of this utility model have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of this utility model is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of this utility model, but all such changes and modifications fall within the scope of protection of this utility model.

Claims

1. An extrusion molding apparatus for a battery casing, characterized in that, The extrusion molding apparatus for the battery casing includes an extrusion die and a heating element; The extrusion die includes an outer extrusion die and an inner extrusion die. The outer extrusion die is sleeved on the outer periphery of the inner extrusion die, and a space for forming a battery casing is formed between the outer extrusion die and the inner extrusion die for the solidification of molten steel. At least one of the outer extrusion die and the inner extrusion die has a receiving cavity inside, and the heating element is disposed in the receiving cavity. The working temperature of the heating element is lower than the melting point of the molten steel.

2. The extrusion molding apparatus for a battery casing as described in claim 1, characterized in that, The receiving cavity includes a first receiving cavity disposed inside the extrusion outer mold, and the heating element includes a first heating element disposed within the first receiving cavity; The battery casing forming space has multiple side portions along its circumference, and at least one of the first heating elements is provided on the outer periphery of each side portion.

3. The extrusion molding apparatus for a battery casing as described in claim 1, characterized in that, The extrusion molding apparatus for the battery casing further includes a positioning element, which is connected to the extrusion die and extends beyond the extrusion die along the length direction of the space formed by the battery casing.

4. The extrusion molding apparatus for a battery casing as described in claim 3, characterized in that, The receiving cavity includes a second receiving cavity disposed inside the extrusion inner mold, and the heating element includes a second heating element disposed within the second receiving cavity; The positioning member is fixed on the extrusion inner mold, and the positioning member is provided with the second heating element on both sides along the width direction of the space formed by the battery housing.

5. The extrusion molding apparatus for a battery casing as described in claim 4, characterized in that, The positioning element is located at the center of the extrusion inner die, and the extrusion inner die is provided with a plurality of second receiving cavities, which are symmetrical with respect to the positioning element.

6. The extrusion molding apparatus for a battery casing as described in any one of claims 1-5, characterized in that, The receiving cavity extends through both ends of the extrusion die along the length direction of the battery housing forming space, and the length of the heating element in the length direction of the battery housing forming space is equal to the length of the receiving cavity in the length direction of the battery housing forming space.

7. The extrusion molding apparatus for a battery casing as described in any one of claims 1-5, characterized in that, The wall thickness of the space formed by the battery casing is 0.2~1mm.

8. The extrusion molding apparatus for a battery casing as described in any one of claims 1-5, characterized in that, The operating temperature of the heating element is 800~1000℃.

9. The extrusion molding apparatus for a battery casing as described in claim 8, characterized in that, The heating element is a nickel-chromium resistance heating rod.

10. A battery casing, characterized in that, The battery casing is formed by an extrusion molding apparatus for battery casing as described in any one of claims 1-9, and the material of the battery casing is steel.

Images