CN110899503B

CN110899503B - A stretch forming die for a battery casing

Info

Publication number: CN110899503B
Application number: CN201911214794.0A
Authority: CN
Inventors: 杨浩; 周勤勇
Original assignee: Wuxi Jinyang New Material Co ltd
Current assignee: Wuxi Jin Yang Precision Manufacturing Co., Ltd.
Priority date: 2019-12-02
Filing date: 2019-12-02
Publication date: 2025-12-05
Anticipated expiration: 2039-12-02
Also published as: CN110899503A

Abstract

The application discloses a stretching forming die of a battery shell, which comprises a punch and a stretching female die, wherein the stretching female die comprises an upper female die and a lower female die, an upper stretching cavity is formed in the upper female die, a female die inlet is formed in the upper part of the upper stretching cavity, an inlet R angle is formed in the female die inlet, the inner diameter of the upper stretching cavity is gradually decreased from top to bottom, a lower stretching cavity is formed in the lower female die, the inner diameter of the lower stretching cavity is gradually decreased from top to bottom, and the inner diameter of a port at the lower end of the upper stretching cavity is larger than the inner diameter of a port at the upper end of the lower stretching cavity. The battery shell punched by the method has the advantages that the rust resistance is improved by 3-4 grades, so that the service life of the battery is longer, and the safety performance is higher.

Description

Stretching forming die for battery case

Technical Field

The invention relates to the technical field of stretching dies, in particular to a stretching forming die for a battery shell.

Background

Lithium ion batteries are rechargeable batteries that operate primarily by virtue of lithium ions moving between a positive electrode and a negative electrode. In the charge and discharge process, li+ is inserted and removed back and forth between the two electrodes, wherein Li+ is removed from the positive electrode when the battery is charged, is inserted into the negative electrode through the electrolyte, and is in a lithium-rich state when the battery is discharged, and the reverse is achieved. The lithium ion battery has the characteristics of small volume, light weight, strong electric quantity, environment friendliness and the like, and is widely applied to industrial production and daily life.

The battery shell is an important component of a lithium ion battery, the battery shell of the lithium ion battery in the existing market is punched by adopting a drawing forming die shown in fig. 1, however, as a drawing cavity in the drawing forming die is a straight section and the R angle at the inlet is smaller, generally 0.5mm-1.0mm is taken, during drawing, a workpiece is thinned by a thickness, the deformation and sliding of the material are all completed on one point of the R angle of the inlet, and as the R angle is an arc, the workpiece can only be contacted with a tangent point, namely, the size of the workpiece is already shaped and the drawing is completed as soon as the workpiece enters the R angle, the lower working section only plays a role of maintaining and fixing the size, in the whole process, the workpiece is contacted with a drawing die in an annular line contact manner from the circumferential direction, the interaction time of the workpiece and the drawing die is short, the area is small, and the degree of instantaneous deformation of the material is large. Thus, the solution is urgently needed.

Disclosure of Invention

The invention aims to solve the problems of poor rust resistance and short service life of the traditional battery shell by providing a stretching and forming die for the battery shell.

The invention aims at realizing the following technical scheme:

the utility model provides a tensile forming die of battery case, includes drift and tensile die, tensile die includes die, lower die, it has last tensile die cavity to go up to open on the die, just it is located to go up on the die go up tensile die cavity's upper portion is provided with the die entry, die entry department is provided with entry R angle, go up tensile die cavity's internal diameter and decrease in proper order from top to bottom, it has lower tensile die cavity to open on the lower die, the internal diameter of lower tensile die cavity decreases in proper order from top to bottom, go up tensile die cavity lower extreme port's internal diameter is greater than lower tensile die cavity upper end port's internal diameter.

As a preferred embodiment of the present invention, the inlet R angle is 3mm.

As a preferable scheme of the invention, a guide opening is arranged on the upper part of the upper female die, which is positioned at the inlet of the female die, and the caliber of the guide opening is gradually decreased from top to bottom.

As a preferable scheme of the invention, a blanking port is arranged on the lower die and positioned at the lower part of the lower stretching die cavity, and the caliber of the blanking port is sequentially increased from top to bottom.

As a preferable scheme of the invention, a blanking opening is arranged on the upper concave die and positioned at the lower part of the upper stretching die cavity, and the caliber of the blanking opening is sequentially increased from top to bottom.

As a preferable scheme of the invention, a feeding hole is arranged on the lower concave die and positioned at the upper part of the lower stretching die cavity, and the caliber of the feeding hole is gradually decreased from top to bottom.

In the application, the stretching female die adopts 2 upper female dies and 2 lower female dies, the working sections of the upper female die and the lower female die are conical, and the size difference of 0.02mm-0.04mm is reserved at the upper opening and the lower opening of each working section, so that the rough thinning of a workpiece is finished in the stretching female die section by section in the stretching process, and is not finished instantaneously, thereby prolonging the time of material deformation, delaying the degree of deformation and playing the roles of reducing rebound and fixing the size. Meanwhile, the R angle at the inlet is increased, so that the workpiece can enter the cavity more smoothly. In addition, due to the sectional conical stretching, the deformation of the material is not concentrated on one point of the inlet R angle, but distributed on the whole contact surface of the two working sections, so that the contact area of the workpiece and the stretching female die is increased, the line contact is changed into the surface contact, the acting time of the workpiece and the stretching female die is prolonged, and the surface of the material is continuously extruded to be smooth and smooth under the action of extrusion force, thereby obtaining a surface similar to mirror surface brightness.

The battery shell punched by the method has the beneficial effects that the rust resistance of the battery shell is improved by 3-4 grades, so that the service life of the battery is longer, and the safety performance is higher.

Drawings

Fig. 1 is a schematic structural view of a conventional stretch-forming mold for a battery case;

fig. 2 is a schematic structural view of a stretch-forming mold of a battery case;

FIG. 3 is a schematic structural view of the upper die;

Fig. 4 is a schematic structural view of the lower die.

Detailed Description

The technical scheme of the invention is further described below by the specific embodiments with reference to the accompanying drawings. It is to be understood that the embodiments described herein are merely illustrative of the invention and are not limiting thereof.

Referring to fig. 2 to 4, fig. 2 is a schematic structural view of a drawing mold for a battery case, fig. 3 is a schematic structural view of an upper die, and fig. 4 is a schematic structural view of a lower die.

In this embodiment, a stretch forming die of battery case, including drift 1 and tensile die, tensile die includes die 2, lower die 3, it has last tensile die cavity 21 to go up to open on the die 2, just it is located to go up the die 2 go up the upper portion of tensile die cavity 21 is provided with die entry 22, die entry 22 department is provided with entry R angle, entry R angle is 3mm, it is located to go up the die 2 the upper portion of die entry 22 is provided with guiding port 23, the bore of guiding port 23 is progressively decreased from top to bottom in proper order, the bore of going up tensile die cavity 21 is progressively decreased from top to bottom in proper order, it is located to go up the die 2 the lower part of tensile die cavity 21 is provided with the feed opening, the bore of feed opening is progressively increased from top to bottom in proper order, lower die cavity 31 is progressively decreased from top to bottom in proper order, lower die 3 is located the lower part of tensile die cavity 31 is provided with blanking opening 32, the bore of feed opening is progressively decreased from top to bottom in proper order, the bore of feed opening is progressively increased from top to bottom in proper order is located to lower opening 31.

The battery shell punched and formed by the method has good smoothness, and the following table is a surface roughness comparison table of the battery shell punched and formed by the method and the traditional die:

As is clear from the table, the battery case punched and molded by the application has better surface finish, small difference between profile peaks and profile valleys in microscopic view, less serious surface roughness phenomenon and difficult adsorption and accumulation of corrosive medium, thereby having higher rust resistance.

To further verify the above conclusions, corrosion tests were performed on bright-face and matte-face battery cases, the plating thicknesses of the two battery cases being identical, and the results are shown in the following table:

test item	Bright face battery case	Matte battery case
			High temperature and high humidity test for 7 days	Non-reaction	Rust spot appears
Soaking in 5% saline at 20deg.C for 30 min	Non-reaction	Rust spot appears
			Salt spray test for 2 hours	Grade 8 or more	4-5 Grade

As shown in the test data of the table, the rust-proof capacity of the battery case manufactured by punching and forming the battery case can be improved by 3-4 grades.

The above embodiments merely illustrate the basic principles and features of the present invention, and the present invention is not limited to the above embodiments, but can be variously changed and modified without departing from the spirit and scope of the present invention, which is within the scope of the present invention as claimed. The scope of the invention is defined by the appended claims.

Claims

1. The stretching forming die for the battery shell comprises a punch and a stretching die and is characterized in that the stretching die comprises an upper die and a lower die, the working sections of the upper die and the lower die are conical, an upper stretching die cavity is formed in the upper die, a die inlet is formed in the upper part of the upper die, which is located in the upper stretching die cavity, an inlet R angle is formed in the die inlet, the inner diameter of the upper stretching die cavity is sequentially decreased from top to bottom, a lower stretching die cavity is formed in the lower die, the inner diameter of the lower stretching die cavity is sequentially decreased from top to bottom, and the inner diameter of a port at the lower end of the upper stretching die cavity is larger than the inner diameter of a port at the upper end of the lower stretching die cavity;

a blanking port is arranged on the lower concave die and positioned at the lower part of the lower stretching cavity, and the caliber of the blanking port is sequentially increased from top to bottom;

The upper female die is provided with a blanking opening at the lower part of the upper stretching cavity, and the caliber of the blanking opening increases gradually from top to bottom.

2. The stretch-forming die for a battery case according to claim 1, wherein the inlet R angle is 3mm.

3. The stretch-forming die of claim 1, wherein the upper die is provided with a guide opening at the upper part of the die inlet, and the caliber of the guide opening decreases from top to bottom.

4. The stretch-forming die of the battery shell according to claim 1, wherein a feed port is formed in the lower die and located at the upper portion of the lower stretch-forming die cavity, and the caliber of the feed port decreases from top to bottom in sequence.