CN204596873U - A kind of upper insulating trip of cylindrical lithium ion battery - Google Patents

Abstract

The utility model relates to an upper insulating sheet of a cylindrical lithium ion battery, which comprises a circular gasket body. The circular gasket body is provided with a positive electrode ear via hole and a plurality of reserved holes, and the plurality of reserved holes include a first Hole, second hole and third hole, the first hole is set in the middle of the circular gasket body, and the circular gasket body is divided into four azimuth areas of upper, lower, left and right with the first hole as the center, the second The second hole and the third hole are symmetrically arranged in the left and right areas of the first hole, respectively, the positive tab via hole is arranged in the upper or lower area of the first hole, and there is no reserved hole in the other area. The upper insulating sheet of the utility model avoids large self-discharge or safety problems caused by the short circuit of the positive tab through the upper insulating sheet and the negative electrode sheet inside the cell.

Description

An upper insulating sheet of a cylindrical lithium-ion battery

technical field

The utility model belongs to the technical field of lithium ion batteries and relates to an upper insulating sheet of a cylindrical lithium ion battery.

Background technique

Lithium-ion batteries are more and more closely related to people's lives, and people pay more and more attention to the safety of lithium-ion batteries, and the safety requirements are becoming more and more stringent. This application is aimed at further improving the safety performance of cylindrical lithium-ion batteries. The insulating sheet on the cylindrical lithium-ion battery cell has the isolation function of the positive tab and the winding core sheet, and is essential. Its structure and mechanical properties are closely related to the safety of lithium secondary batteries.

At present, the insulating sheet on the cylindrical battery mostly adopts the spider web structure shown in Figure 1, the annular porous structure shown in Figure 2, the porous irregular arrangement structure shown in Figure 3 and the annular 5-hole plus structure shown in Figure 4. tab via structure, etc.

The advantage of the spider web structure is that it is easy to assemble multi-tab batteries. The disadvantages are: 1. The positive tabs are easily inserted upside down through the reserved space, resulting in a short circuit inside the battery, causing large self-discharge or safety problems. 2. The safety valve of the cap It is relatively difficult to open. 3. The mechanical properties are poor and easy to deform.

The advantage of the annular porous structure is that the mechanical properties are relatively good, and it is not easy to deform. The disadvantages are: 1. The positive tab is easy to be inserted through the reserved hole, resulting in a short circuit inside the battery, causing large self-discharge or safety problems. 2. Cap safety valve It is relatively difficult to open; 3. The production process is not easy to operate and the efficiency is low.

The advantage of the porous irregular arrangement structure is that the mechanical properties are relatively good, and it is not easy to deform. The disadvantages are 1. The positive ear is easy to be inserted through the reserved hole, resulting in a short circuit inside the battery, causing large self-discharge or safety problems. 2. Cap It is relatively difficult to open the safety valve. 3. The production process is difficult to operate and the efficiency is low.

The advantages of the ring-shaped 5-hole plus tab via hole structure are: relatively good mechanical properties, not easy to deform, easy to operate in the production process, and relatively high efficiency; the disadvantages are: 1. The positive tab is easy to be inserted backward through the reserved hole, resulting in The internal short circuit of the battery causes large self-discharge or safety problems; 2. It is relatively difficult to open the safety valve of the cap.

Contents of the invention

In order to solve the technical problem that the upper insulating sheet of the existing cylindrical lithium-ion battery cannot prevent the positive tab from being inserted backward through the reserved hole, resulting in a short circuit inside the battery, the utility model provides an upper insulating sheet of the cylindrical lithium-ion battery.

The technical solution of the utility model is as follows:

An upper insulating sheet of a cylindrical lithium-ion battery, comprising a circular gasket body, the circular gasket body is provided with a positive tab hole and a plurality of reserved holes, characterized in that: the plurality of reserved holes The holes include a first hole, a second hole and a third hole, the first hole is arranged in the middle of the circular gasket body, and the circular gasket body is divided into upper, lower, left and right with the first hole as the center four orientation areas,

The second hole and the third hole are respectively symmetrically arranged in the left and right regions of the first hole, the positive tab via hole is arranged in the upper or lower region of the first hole, and there is no reserved hole in the other region; or ,

The second hole and the third hole are respectively arranged symmetrically in the upper and lower regions of the first hole, the positive tab via holes are arranged in the left or right region of the first hole, and there is no reserved hole in the other region.

The above-mentioned positive tab hole is an annular groove centered on the center of the circular gasket body, and the angle range of the annular groove is 30-90 degrees.

The shape of the first hole is a circle, and the shape of the second hole and the third hole is a circle or other shapes.

Both the area of the second hole and the area of the third hole are smaller than the area of the first hole.

The shortest distance between the positive tab hole and the circular gasket body is greater than 2mm.

Compared with the prior art, the utility model has the advantages of:

1. The utility model removes the reserved hole in the opposite area of the positive tab, avoiding the large self-discharge or safety problems caused by the positive tab being inserted upside down through the upper insulating sheet and the negative electrode inside the battery to form a short circuit;

2. After adopting the upper insulating sheet of the utility model, the cylindrical lithium-ion battery is easy to operate when the insulating sheet is put on when the cell is assembled, and the work efficiency can be improved;

3. The number of reserved holes in the utility model is reduced, so the mechanical properties are better and the deformation is not easy to occur;

4. The utility model removes the reserved hole in the relative area of the positive tab. When exhausting, the gas is only discharged through the first hole, the second hole, the third hole, and the tab hole. Further, the utility model passes The structural design of the area of the second hole and the third hole is smaller than the area of the first hole, so that the gas pressure passing through the first hole is effectively increased, and the cap can be opened quickly even under a small internal pressure. The valve can make the battery form an open circuit, reduce the safety hazards caused by the quality defects of the battery itself or improper use, and further improve the safety performance of the lithium-ion battery.

Description of drawings

Figure 1 shows the upper insulating sheet of the spider web structure;

Figure 2 shows the upper insulating sheet of the annular porous structure;

Figure 3 shows the upper insulating sheet with porous irregular arrangement structure;

Figure 4 shows the upper insulating sheet with a ring-shaped 5-hole plus lug via hole structure;

Fig. 5 shows the structural diagram of the upper insulating sheet of the present utility model;

Figure 6 is a schematic diagram of the state after the positive tab passes through the tab hole;

Figure 7 shows the assembled cylindrical lithium-ion battery.

Wherein reference sign is:

1- tab bend, 2- tab opposite area, 3- tab via, 4- CID, 5- welding, 6- upper insulating sheet, 7- roll core, 8- positive tab, 9-cap, 61-lug via, 62-first hole, 63-second hole, 64-third hole.

Detailed ways

The upper insulating sheet described in the utility model is to improve the safety performance of the lithium-ion battery by adjusting the shape and opening structure of the existing upper insulating sheet.

The utility model adjusts the upper insulating sheet of the annular 5-hole plus tab via structure to the upper insulating sheet of the 2-hole plus tab via structure (that is, the 3 holes facing the tab via holes are canceled, and only the tabs are left to pass through. There is one hole on each side of the hole (as shown in Figure 5), and there is no opening in the area 1 corresponding to the tab via hole.

Figure 7 shows the assembled cylindrical lithium-ion battery. The positive tab of the winding core protrudes from the tab hole 3 and is connected to the cap at the area 5 above the positive tab by welding. There is no opening in the opposite half area of the lug via hole on the insulating sheet, and the cap is pressed down. The angle formed by the positive tab at the bend of the tab 1 cannot pass through the upper insulating sheet and the winding core in the half area opposite to the tab via hole. Contact, that is, no reverse insertion will be formed, causing the tab and the winding core to form a loop, causing safety problems.

Cylindrical lithium-ion batteries are completely sealed and use closed-end formation. During the activation process of the battery and the HF gas generated by the reaction between the residual moisture in the winding core and the organic motor fluid, there will be a certain pressure inside the battery; When the battery is short-circuited or improperly used, the internal temperature of the battery will rise sharply. As the temperature rises, the electrolyte will decompose and produce a large amount of gas. When the pressure reaches 1.0-1.5Mpa, the CID4 (safety valve) pops open, and the battery forms an open circuit. The upper insulating sheet has only 3 holes and the tab via hole structure. Compared with the porous upper insulating sheet, the pressure released by each hole becomes smaller. Large, hole 1 in Figure 6 corresponds to CID 4 after assembly, which makes it easier to open the CID quickly and further improves the safety performance.

Compared with several conventional insulating sheets on the market, the upper insulating sheet of the utility model has the characteristics of high assembly work efficiency and good mechanical properties, and can completely avoid the safety problems caused by the reverse insertion of the positive ear; when the safety of use is endangered, the battery Under the same internal pressure, using the new upper insulating sheet designed by this patent can open the safety device of the cap more quickly and reduce safety hazards.

Claims (5)

1. The utility model provides a cylinder type lithium ion battery's last insulating piece, includes the circular gasket body, be provided with anodal ear via hole (61) and a plurality of preformed hole on the circular gasket body, its characterized in that: the plurality of prepared holes comprise a first hole (62), a second hole (63) and a third hole (64), the first hole (62) is arranged in the middle of the circular gasket body, the circular gasket body is divided into four azimuth areas, namely an upper azimuth area, a lower azimuth area, a left azimuth area and a right azimuth area by taking the first hole (62) as a center,

the second hole (63) and the third hole (64) are respectively and symmetrically arranged in the left area and the right area of the first hole (62), the positive lug through hole (61) is arranged in the upper area or the lower area of the first hole, and the other area is not provided with a reserved hole; or,

the second hole (63) and the third hole (64) are respectively and symmetrically arranged in the upper area and the lower area of the first hole (62), the positive lug through hole (61) is arranged in the left area or the right area of the first hole (62), and the other area is not provided with a reserved hole.

2. The upper insulating sheet of the cylindrical lithium ion battery of claim 1, wherein: the positive lug through hole (61) is an annular groove which takes the center of the circular gasket body as the circle center, and the angle range of the annular groove is 30-90 degrees.

3. The upper insulating sheet of the cylindrical lithium ion battery of claim 2, wherein: the first hole (62) is circular in shape, and the second hole (63) and the third hole (64) are circular in shape.

4. The upper insulating sheet of the cylindrical lithium ion battery of claim 1, 2 or 3, wherein: the area of the second hole (63) and the area of the third hole (64) are both smaller than the area of the first hole.

5. The upper insulating sheet of the cylindrical lithium ion battery of claim 4, wherein: the nearest distance between the positive lug through hole (61) and the circular gasket body is larger than 2 mm.