CN212907805U

CN212907805U - Pole piece and lithium ion battery

Info

Publication number: CN212907805U
Application number: CN202021424001.6U
Authority: CN
Inventors: 李金星; 房华禹; 王俊朋; 郭小林; 王永光
Original assignee: Yinlong New Energy Co Ltd
Current assignee: Yinlong New Energy Co Ltd
Priority date: 2020-07-20
Filing date: 2020-07-20
Publication date: 2021-04-06
Anticipated expiration: 2030-07-20

Abstract

The utility model discloses a pole piece and lithium ion battery, wherein the pole piece includes the mass flow body, and the mass flow body positive and negative both sides have set gradually coating and powder layer, and mass flow body middle part thickness is less than the thickness at both ends, and the coating holds the positive and negative both sides at the mass flow body middle part. The mass flow body, the middle part is regional to carry out the attenuate, both ends thickness is unchangeable, can effectively reduce the thickness in battery utmost point sheet material district, keeps the tensile strength of the regional foil of utmost point ear unchangeable simultaneously.

Description

Pole piece and lithium ion battery

Technical Field

The utility model belongs to the battery field especially relates to a pole piece and lithium ion battery.

Background

At present, in the lithium ion power battery industry, foil with the thickness equal to or larger than 0.02mm is mostly used, the thickness of the manufactured pole piece is high, and the capacity and the energy of the battery under the specified volume are low.

In order to improve the volume energy density of the battery, part of manufacturers try to adopt foil with the thickness less than or equal to 0.02mm, the thickness of the pole piece made of the foil is reduced, the battery with the same volume can contain more pole pieces, and the energy ratio of the battery is effectively improved.

However, in the assembly process of the lithium ion battery, a battery tab (blank foil) needs to be welded to serve as a current collector, the effective welding volume of the foil is reduced due to the reduction of the thickness of the foil, the direct welding strength of the hardware flow guide piece and the aluminum foil is affected, the current density of the battery during discharging and the ohmic polarization of the battery during discharging are increased, particularly, when multiplying power is discharged, the unit current borne by the thin foil during welding is increased when the multiplying power is discharged due to the small effective welding volume of the foil, the welding position is relatively serious in heating, and great potential safety hazards are caused.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a pole piece and lithium ion battery to guarantee the intensity of mass flow body.

In order to achieve the above object, the utility model discloses a pole piece and lithium ion battery's concrete technical scheme as follows:

the utility model provides a pole piece, includes the mass flow body, and the mass flow body tow sides has set gradually coating and powder layer, and the thickness is less than the thickness at both ends in the middle of the mass flow body, and the coating holds the tow sides at the mass flow body middle part.

Further, the current collector comprises a thinning portion located in the middle of the current collector, a constant thickness portion located at two end portions of the current collector, and a transition portion connecting the thinning portion and the constant thickness portion.

Further, the thickness of the constant thickness part is 20-30 μm.

Furthermore, the current collector is formed by laying foil.

Further, the coating is a carbon coating.

Furthermore, an isolating membrane is arranged on the outer side of the powder layer.

A lithium ion battery comprises the pole piece.

Furthermore, the lithium ion battery also comprises a package, wherein electrolyte is filled in the package, the pole piece part is wrapped by the package and soaked in the electrolyte, and the end part of the pole piece extends out of the package to form a positive pole and a negative pole.

Further, the package is formed by hot pressing of an aluminum plastic film.

Further, the package is a housing.

The utility model discloses a pole piece and lithium ion battery have following advantage: the middle area of the foil of the lithium ion battery is thinned, the thicknesses of the two end parts are unchanged, the thickness of a battery pole piece area can be effectively reduced, and meanwhile, the tensile strength of the normally thick part serving as a pole lug area is kept unchanged.

Drawings

Fig. 1 is a schematic diagram of the pole piece layer structure of the present invention.

The notation in the figure is:

1. a current collector; 11. a thinning portion; 12. a transition section; 13. a constant thickness portion; 2. coating; 3. a powder layer; 4. and (3) a barrier film.

Detailed Description

In order to better understand the purpose, structure and function of the present invention, the following description is made in detail with reference to the accompanying drawings.

The utility model discloses a lithium ion battery, including packing and pole piece. The packaging is filled with electrolyte, the pole piece part is wrapped by the packaging and soaked in the electrolyte, and the end part of the pole piece extends out of the packaging to form a positive pole and a negative pole.

The package can be formed by hot pressing an aluminum plastic film, and the lithium ion battery is a soft package lithium ion battery; the package can also be a shell, and the lithium ion battery is a hard shell lithium ion battery.

As shown in fig. 1, the pole piece comprises a current collector 1, and a coating layer 2 and a powder layer 3 are sequentially arranged on the front side and the back side of the current collector 1; the thickness of the middle of the current collector 1 is smaller than the thickness of the two ends, and the coating 2 is contained on the front side and the back side of the middle of the current collector 1. And an isolating film 4 is arranged on the outer side of the powder layer 3 to protect the pole piece.

To facilitate thinning of the central region of current collector 1 by calendaring, electrolysis or other methods, current collector 1 includes a thinned portion 11 located in the middle of current collector 1, a thickened portion 13 located at both ends of current collector 1, and a transition portion 12 connecting thinned portion 11 and thickened portion 13. The thickness of the thick portion 13 is generally 20 μm to 30 μm.

Generally, the current collector 1 is formed by laying foil, and may be aluminum foil, copper foil, or any other material that can substitute for foil. The coating 2 is a carbon coating, and the powder layer 3 is made by the prior art, which is not described in detail in this embodiment.

Therefore, the two end parts of the current collector 1 are thick, the tensile strength and the welding strength are strong, and the potential safety hazard is low; and the middle part is thinner, the battery with the same volume can contain more pole pieces, and the energy ratio of the battery is effectively improved.

It is to be understood that the present invention has been described with reference to certain embodiments, and that various changes or equivalents may be substituted for elements thereof by those skilled in the art without departing from the spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of the present application are intended to be covered by the present invention.

Claims

1. The utility model provides a pole piece, includes mass flow body (1), and mass flow body (1) tow sides has set gradually coating (2) and powder layer (3), its characterized in that, and mass flow body (1) middle part thickness is less than the thickness at both ends, and coating (2) hold the tow sides at mass flow body (1) middle part.

2. The pole piece according to claim 1, characterized in that the current collector (1) comprises a thinned portion (11) located in the middle of the current collector (1), a thickened portion (13) located at both ends of the current collector (1), and a transition portion (12) connecting the thinned portion (11) and the thickened portion (13).

3. Pole piece according to claim 2, characterized in that the thickness of the thick portion (13) is 20 μm to 30 μm.

4. The pole piece according to claim 1, characterized in that the current collector (1) is laid out of foil.

5. Pole piece according to claim 1, characterized in that the coating (2) is a carbon coating.

6. The pole piece according to claim 1, characterized in that the powder layer (3) is provided with a separating film (4) on the outside.

7. A lithium ion battery comprising a pole piece according to any one of claims 1 to 6.

8. The lithium ion battery of claim 7, further comprising a package filled with an electrolyte, wherein the pole piece portion is wrapped by the package and soaked in the electrolyte, and the end of the pole piece extends out of the package to form a positive electrode and a negative electrode.

9. The lithium ion battery of claim 8, wherein the package is formed by hot pressing an aluminum plastic film.

10. The lithium ion battery of claim 8, wherein the package is a housing.