CN209963149U

CN209963149U - Anti-bending pole piece

Info

Publication number: CN209963149U
Application number: CN201920776579.9U
Authority: CN
Inventors: 谭歌; 韩笑; 李凡群; 夏塞塞; 陈阳; 张伟; 张建勇; 万华峰; 王海伦
Original assignee: Wanxiang Group Corp; Wanxiang A123 Systems Asia Co Ltd
Current assignee: Wanxiang A123 Systems Asia Co Ltd
Priority date: 2019-05-27
Filing date: 2019-05-27
Publication date: 2020-01-17
Anticipated expiration: 2029-05-27

Abstract

The utility model relates to a battery technology field, in order to overcome prior art because the effect of rolling stress leads to the mass flow body to one side bending, and the problem of bending aggravation after towards the piece and toasting, provide an anti bending pole piece, including conducting foil and the active material coating of coating in the conducting foil both sides, conducting foil includes first district and second district, thickness is 6 mu m ~ 30 mu m, the second district is connected to the first district, first district contains active material coating district, be equipped with the additional strengthening who is formed by continuous depth stamp that links to each other with first district in the second district, additional strengthening is regional at distance coating edge 3 ~ 6mm, the stamp shape is netted circular or polygon, the degree of depth is 3 ~ 10 mu m. The utility model discloses a can avoid electric core lamination in-process, the mass flow body is to a lateral bending, can effectively solve the problem that the mass flow body leaked the welding with the welded seat collision and the mass flow body in welding process to avoid because the battery that leaks to weld and lead to holds and safe risk lowly.

Description

Anti-bending pole piece

Technical Field

The utility model belongs to the technical field of a lithium ion battery technique and specifically relates to an anti crooked pole piece is related to.

Background

The pole piece is a small unit structure which is composed of active substances and conductive foil and has the function of lithium ion insertion and extraction, wherein the active substances are distributed on two sides of the conductive foil. The pole piece is bent to one side due to the action of rolling stress in the pole piece rolling process, and meanwhile, the pole piece is bent to one side and aggravated after the pole piece is stamped. The bending can be more serious in the pole piece baking process, the bending angle causes that in the lamination process of the battery core, the conductive foil is bent towards one side of the battery core, and the pole piece is collided at a welding seat and is not welded with the pole piece in the welding process. Resulting in low battery capacity and also a safety risk.

For example, a "current collector coating and electrode sheet" disclosed in chinese patent document, publication No. CN 207558937U includes: the protective layer is formed on the surface of the current collector, the active material is formed on the protective layer, the protective layer comprises expansion microspheres and a conductive agent, the active material layer comprises the active material, and the expansion microspheres expand when the temperature of the protective layer is greater than or equal to a temperature threshold value, so that the current collector is disconnected from the active material layer. According to the technical scheme, on the premise that the energy density of the unit volume of the battery is not reduced and the production cost of the battery is not increased, the battery is ensured not to continue to be charged and discharged when the temperature is too high, and the safety of the battery is improved. But does not solve the problem of the current collector that the bending is aggravated after punching and baking.

SUMMERY OF THE UTILITY MODEL

The utility model relates to an overcome because the effect of rolling stress leads to the pole piece to a lateral bending to make the problem of crooked aggravation after towards the piece and toasting, provide an anti-bending pole piece.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

the utility model provides an anti-bending pole piece, the pole piece includes conductive foil and the active material coating of coating in conductive foil both sides, and conductive foil includes first district and second district, and the second district is connected in first district, and first district is the active material coating, is equipped with the additional strengthening that forms by continuous degree of depth stamp on the second district, and the additional strengthening meets with first district. The pole piece that additional strengthening can solve rolling stress and lead to is to the problem of lateral buckling, can solve simultaneously towards the piece with toast the problem of pole piece bending aggravation after, avoid electric core lamination in-process, the pole piece is to lateral buckling, effectively solves pole piece and the problem that the seat collided and the pole piece leaks to weld in welding process.

Preferably, the reinforcing structures are distributed on two side faces of the conductive foil in the area 3-6 mm away from the edge of the coating. This area is prone to bending when rolled and die cut to form the pole pieces, so a printed reinforcement structure is added to prevent bending.

Preferably, the printing of the reinforcing structure is a net-shaped circle. The structure has stability, and the stress can be dispersed to achieve the effect of bending resistance.

Preferably, the diameter of the round single body is 1-3 mm. The diameter is smaller than the width of the conductive foil, so that the printing can be distributed on the conductive foil as much as possible.

Preferably, the printing of the reinforcing structure is a net polygon. The structure has stability, and the stress can be dispersed to achieve the effect of bending resistance.

Preferably, the side length of each polygon is 2-5 mm. The diameter is smaller than the width of the conductive foil, so that the printing can be distributed on the conductive foil as much as possible.

Preferably, the reinforcing structure has a depth of 3 to 10 μm on the conductive foil side. The reinforcing structures are arranged at the top end and the bottom end of the conductive foil, and a blank conductive foil is reserved between the two reinforcing structures, so that the depth of each layer is less than half of the thickness of the conductive foil.

Preferably, the conductive foil is a metal foil having a thickness of 6 to 30 μm and a width of 10 to 20 mm. The thickness of the foil should be greater than the thickness of the two layers of the reinforcing structure and the width should be such as to accommodate a certain number of different shapes of the printing.

Preferably, the rolling design compaction density of the pole piece is 1.6g/cm³. The pole piece is compressed in volume by rolling, so that the impedance can be reduced, and the multiplying power performance of the battery is improved.

Therefore, the utility model discloses following beneficial effect has: (1) the reinforcing structure can solve the problem that the pole piece is bent towards one side caused by rolling stress; (2) the problem of aggravation of bending of the pole piece after punching and baking can be solved, and the pole piece is prevented from being bent towards one side in the lamination process of the battery cell; (3) thereby solving the problems of pole piece and welding seat collision and pole piece welding leakage in the welding process.

Drawings

Fig. 1 is a schematic structural diagram of the present invention.

Fig. 2 is a schematic structural view of the cross section a-a of the present invention.

Fig. 3 is a partial enlarged view at B in fig. 2.

In the figure: 1. active material coating 2, conductive foil 3, reinforcing structure.

Detailed Description

The present invention will be further described with reference to the accompanying drawings and the detailed description.

In the embodiment shown in fig. 1, 2 and 3, the anti-bending pole piece comprises a conductive foil 2 and an active substance coating 1 coated on two sides of the conductive foil, wherein the conductive foil comprises a first area and a second area, the first area is connected with the second area, the first area is provided with the active substance coating area, the active substance coating can provide static conductivity, and microcurrent of an active substance is collected, so that the contact resistance between a positive/negative electrode material and current collection is greatly reduced. The second zone is provided with a reinforcing structure 3 formed by continuous deep printing, and the reinforcing structure is connected with the first zone. The effect of rolling stress can lead to conducting foil to one side bending at the in-process that the pole piece rolled, can make crooked aggravation behind the pole piece towards the piece simultaneously, and this additional strengthening dispersibility rolling stress avoids crooked problem.

The reinforcing structure is 3-10 μm deep on one side of the conductive foil, 3-6 mm long, and distributed on the upper and lower sides of the conductive foil. The conductive foil is a metal foil with the thickness of 6-30 mu m and the width of 10-20 mm, and the width of the area without active substances at the blank at the two sides of the conductive foil is 10-20 mm. The designed compaction density of the pole piece roll is 1.6g/cm³。

Furthermore, the printing of the reinforcing structure is in a shape of a net triangle which is uniformly arranged, and stress can be dispersed when the pole piece is rolled. The printing can also be other reticular polygons or reticular circles. When the printing is a reticular polygon, the side length of the polygon is 2-5 mm, and when the printing is a reticular circle, the diameter of the circle is 1-3 mm.

The above embodiments are only for illustrating the technical conception and the features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and the protection scope of the present invention cannot be limited thereby, and all equivalent changes, modifications or improvements made according to the spirit of the present invention should be covered by the protection scope of the present invention.

Claims

1. The utility model provides an anti-bending pole piece, characterized by, the pole piece includes conducting foil (2) and coating active material coating (1) in conducting foil both sides, and conducting foil includes first district and second district, and the second district is connected in the first district, and the first district is equipped with active material coating, is equipped with on the second district by continuous degree of depth stamp formation additional strengthening (3), and additional strengthening meets with the first district.

2. The bending-resistant electrode sheet as claimed in claim 1, wherein the reinforcing structure has a length of 3 to 6mm and is disposed on both sides of the conductive foil.

3. A bend-resistant pole piece as claimed in claim 1 or claim 2, wherein the reinforcing structure is printed in the form of a net-like circle.

4. A flexure-resistant pole piece as claimed in claim 3, wherein the diameter of the circular individual piece is 1 to 3 mm.

5. A bend-resistant pole piece as claimed in claim 1 or claim 2, wherein the reinforcing structure is printed in the form of a mesh polygon.

6. A flexure-resistant pole piece as claimed in claim 5, wherein the individual sides of the polygon are 2-5 mm.

7. A bend-resistant pole piece as claimed in claim 1 or 2, wherein the reinforcing structure has a depth of 3 to 10 μm on one side of the conductive foil.

8. The bending-resistant pole piece as claimed in claim 1, wherein the conductive foil is a metal foil with a thickness of 6 μm to 30 μm and a width of 10 mm to 20 mm.

9. The flexure-resistant pole piece of claim 1 wherein said pole piece roll design compaction density is 1.6g/cm³。