Material-saving forming process and forming device for upper cover of battery shell

Abstract

The invention provides a material-saving forming process and device for an upper cover of a battery shell, and the process comprises the steps of staged forming: a pre-pressing stage: respectively pre-pressing a first spring and a second spring through the closing pressure of an upper pressing plate and a mold core and the closing pressure of an upper cutter block and a lower pressing plate to form a preliminary contour; in the final pressing stage, a lower pressing plate continues to downwards compress a second spring through force additionally applied to the upper portion of an upper cutter block till the material is guided to flow, precise stretching is completed, pre-pressing shaping is matched with final pressing shaping, the pattern draft is eliminated, and the blank size is reduced to the product net size; the spring is pressurized in a grading mode, the peak pressure is reduced by 26.4%, the length of the die is shortened by 200 mm, and the manufacturing cost is reduced by 12.5%.

Description

Technical Field

[0001] This invention relates to the field of metal stamping technology, and more specifically, to a material-saving forming process and forming apparatus for a battery casing cover. Background Technology

[0002] With the increasing energy density requirements of new energy vehicle batteries, battery casing covers are trending towards thinner walls and deeper stretching. Traditional closed-loop stamping processes have three major drawbacks: Material waste: Due to the draft angle requirement (>5°), the blank size must cover the draft angle area, resulting in a material utilization rate of only 72% per piece; Excessive energy consumption: A single 670T high-pressure stamping process consumes 3.2kWh of electricity per piece, and the high rebound rate of 18% increases the energy consumption for rework. The mold is bulky: the mold is 3720mm long, uses a lot of steel, and has a high manufacturing cost.

[0003] Existing technological improvements (such as CN112893**B) attempt multi-step stamping, but have not solved the problem of blank size redundancy caused by the draft die structure. Summary of the Invention

[0004] The purpose of this invention is to provide a material-saving molding process for a battery casing cover, comprising the following staged molding steps: Pre-pressing stage: The first spring 7 and the second spring 8 are pre-pressed by the closing pressure of the upper pressure plate 5 and the mold core 3, and the closing pressure of the upper cutting block 6 and the lower pressure plate 2, respectively, forming a preliminary outline; Final pressing stage: The lower pressure plate 2 is further compressed downwards by the additional force applied to the upper part of the upper cutting block 6 to guide the material flow and complete precise stretching. Through pre-pressing and final pressing, draft angle is eliminated, and the blank 4 size is reduced to the net product size; the springs are pressurized in stages, resulting in a 26.4% reduction in peak pressure, a 200mm reduction in mold length, and a 12.5% ​​reduction in manufacturing cost.

[0005] A material-saving molding process for a battery casing cover, characterized by comprising a staged molding step: Pre-compression stage: The first spring 7 and the second spring 8 are pre-compressed by the closing pressure of the upper pressure plate 5 and the mold core 3 and the closing pressure of the upper cutter block 6 and the lower pressure plate 2, respectively, to form a preliminary outline; Final compression stage: The additional force applied to the upper part of the upper blade block 6 continues to compress the lower pressure plate 2 downwards, thus guiding the material flow to complete the precise stretching.

[0006] Furthermore, the final pressing stage adopts an open stretching design, which makes the material flow direction controllable by setting a gradually curved opening edge in the stretching area.

[0007] Furthermore, the radius of curvature of the opening edge is 5-8 times the material thickness, and the opening angle is 20°-30°.

[0008] Furthermore, the pressure of pre-compressing the first spring 7 and the second spring 8 is less than the pressure required to compress the second spring 8 to guide the material flow and complete precise stretching, so as to achieve graded pressure control.

[0009] A molding apparatus for achieving a material-saving molding process for a battery casing cover includes an upper mold assembly 1 and a lower mold assembly, characterized in that: the upper mold assembly 1 includes an independently driven upper pressure plate 5 and an upper cutting block 6; the lower mold assembly includes a lower pressure plate 2 corresponding to the upper cutting block 6 and a mold core 3 corresponding to the upper pressure plate 5; a first spring 7 is provided on the upper part of the upper pressure plate 5, and a second spring 8 is provided on the lower part of the lower pressure plate 2.

[0010] Furthermore, the upper blade block 6 and the mold core 3 are provided with a matching ramp surface at the pressing point to disperse concentrated stress.

[0011] The beneficial effects of this invention are as follows: This invention proposes a material-saving molding process for a battery casing cover, including a phased molding process: Pre-pressing stage: The first spring 7 and the second spring 8 are pre-pressed by the closing pressure of the upper pressure plate 5 and the mold core 3 and the closing pressure of the upper cutting block 6 and the lower pressure plate 2, respectively, to form a preliminary outline; Final pressing stage: The lower pressure plate 2 is further compressed downward by the additional force applied to the upper part of the upper cutting block 6 to guide the material flow and complete the precise stretching. Through pre-pressing and final pressing, the draft angle is eliminated, and the size of the blank 4 is reduced to the net size of the product; the springs are pressurized in stages, the peak pressure is reduced by 26.4%, the mold length is shortened by 200mm, and the manufacturing cost is reduced by 12.5%. Attached Figure Description

[0012] Figure 1 This is a structural diagram of the material-saving molding device for the battery casing cover of the present invention.

[0013] Figure 2 This is a simplified diagram of the material-saving molding apparatus for the battery casing cover of the present invention.

[0014] Figure 3 This is a structural diagram of a traditional device.

[0015] Figure 4 This is a simplified diagram of a traditional device.

[0016] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention.

[0017] Upper mold 1; lower pressure plate 2; mold core 3; blank 4; upper pressure plate 5; upper blade block 6; first spring 7; second spring 8; lower pressure plate spring 9. Detailed Implementation

[0018] The following embodiments are described to aid in understanding this application. These embodiments are not, and should not be, construed in any way as limiting the scope of protection of this application.

[0019] In the following description, those skilled in the art will recognize that throughout this discussion, components may be described as individual functional units (which may include subunits), but those skilled in the art will recognize that various components or portions thereof may be divided into individual components or may be integrated together (including integrated within a single system or component).

[0020] Furthermore, the connection between components or systems is not intended to be limited to a direct connection; on the contrary, data between these components may be modified, reformatted, or otherwise altered by intermediate components. Additionally, other or fewer connections may be used. It should also be noted that the terms "connection," "link," or "input" should be understood to include direct connections, indirect connections via one or more intermediate devices, and wireless connections.

[0021] Example 1: like Figure 1 and Figure 2 As shown, a molding apparatus for achieving a material-saving molding process for a battery casing cover includes an upper mold assembly 1 and a lower mold assembly. The upper mold assembly 1 comprises an independently driven upper pressure plate 5 and an upper cutting block 6; the lower mold assembly comprises a lower pressure plate 2 corresponding to the upper cutting block 6, and a mold core 3 corresponding to the upper pressure plate 5; a first spring 7 is provided on the upper part of the upper pressure plate 5, a second spring 8 is provided on the lower part of the lower pressure plate 2, and a matching ramp surface is provided at the pressing point between the upper cutting block 6 and the mold core 3 to disperse concentrated stress.

[0022] like Figure 3 and Figure 4 As shown, the device of the traditional process includes an upper mold 1, a lower pressure plate 2 and a mold core 3. The lower part of the upper mold 1 is provided with the mold core 3 and the lower pressure plate 2. The lower pressure plate 2 is provided with a lower pressure plate spring 9 on both sides near the mold core 3.

[0023] Example 2: A material-saving molding process for a battery casing cover includes a phased molding process: a pre-pressing stage, in which the first spring 7 and the second spring 8 are pre-pressed by the closing pressure of the upper pressure plate 5 and the mold core 3, and the closing pressure of the upper cutting block 6 and the lower pressure plate 2, respectively, to form a preliminary outline; and a final pressing stage, in which the lower pressure plate 2 is further compressed downward by the additional force applied to the upper part of the upper cutting block 6 until the material flow is guided to complete precise stretching. The final pressing stage adopts an open stretching design, in which a gradually changing arc-shaped opening edge is set in the stretching area to make the material flow direction controllable. The radius of curvature of the opening edge is 5-8 times the material thickness, and the opening angle is 20°-30°. The pressure of pre-pressing the first spring 7 and the second spring 8 is less than the pressure of compressing the second spring 8 to guide the material flow to complete precise stretching, so as to achieve graded pressure control.

[0024] The traditional process involves the following steps: the upper mold 1 and the lower pressure plate 2 are closed and pre-pressed. Then, the upper mold 1 uses additional force applied from above to press the lower pressure plate spring 9 to the bottom until the material flows and completes the precise stretching.

[0025] Comparison of effects:

[0026] Example 3: Comparative Example 1: Using only staged pressure without an opening design, the billet size is 2350mm × 1660mm, the savings rate is only 4.8%, and the sidewall wrinkling rate is 12%, proving that both the opening structure and staged pressure are indispensable.

[0027] Comparative Example 2: Opening angle β=35° exceeds the protection range: material flow is out of control, and the cracking rate is as high as 18%.

[0028] This invention features an opening angle of 20°-30°, no sidewall wrinkles, and no cracks. When the opening angle is 25°, the blank size 4 is reduced to the theoretical minimum.

[0029] Example 4: Comparative Example 1: When staged pressure is used, the opening angle is 25°, R<5t, the arc curvature is insufficient, the flow resistance increases, the wrinkling rate increases, when R=4t, the wrinkling rate rises back to 10%, when R>8t, the guiding effect weakens, the material overflows, when R=9t, the dimensional deviation exceeds ±0.1mm, proving that the arc radius of the opening edge is 5-8 times the material thickness.

[0030] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A material-saving molding process for a battery casing cover, characterized in that, Includes phased molding steps: Pre-pressing stage: The first spring (7) and the second spring (8) are pre-pressed by the closing pressure of the upper pressure plate (5) and the mold core (3) and the closing pressure of the upper cutter block (6) and the lower pressure plate (2) respectively, forming a preliminary outline; Final compression stage: The lower pressure plate (2) is further compressed downward by the additional force applied to the upper part of the upper blade block (6) to compress the second spring (8) until the material flow is guided to complete the precise stretching.

2. The process as described in claim 1, characterized in that, The final compression stage adopts an open stretching design, which makes the material flow direction controllable by setting a gradually curved opening edge in the stretching area.

3. The process as described in claim 2, characterized in that, The radius of curvature of the opening edge is 5-8 times the material thickness, and the opening angle is 20°-30°.

4. The process as described in claim 1, characterized in that, The pressure of pre-compressing the first spring (7) and the second spring (8) is less than the pressure of compressing the second spring (8) to guide the material flow to complete the precise stretching, so as to achieve graded pressure control.

5. A molding apparatus for implementing any one of the processes of claims 1-4, comprising an upper mold (1) assembly and a lower mold assembly, characterized in that: The upper mold (1) assembly includes an independently driven upper pressure plate (5) and an upper cutting block (6). The lower mold assembly includes a lower pressure plate (2) corresponding to the upper cutter block (6) and a mold core (3) corresponding to the upper pressure plate (5); The upper part of the upper pressure plate (5) is provided with a first spring (7), and the lower part of the lower pressure plate (2) is provided with a second spring (8).

6. The molding apparatus as described in claim 5, characterized in that, The upper blade block (6) and the mold core (3) are provided with a matching slope surface at the pressing point to disperse concentrated stress.

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