Lithium ion battery pole piece and lithium ion battery comprising pole piece

Abstract

The invention belongs to the technical field of lithium ion battery, and especially relates to a lithium ion battery pole piece. The pole piece comprises a current collector and an active substance layer arranged on the surface of the current collector. A plurality of protrusions and recesses are arranged on the active substance layer. Compared with prior art, According to the invention, the protrusions and recesses are arranged on the active substance layer, such that a pole piece with a unique convex-concave structure is formed. During the battery application process, when anode pole piece volume expansion occurs, the shape of a corresponding cathode pole piece is basically maintained, such that anode pole piece expansion can be limited and induced, such that anode pole piece expansion degree and irregularity can be reduced. Therefore, battery appearance deformation and subsequent battery performance deterioration caused by anode expansion can be effectively inhibited. Therefore, the pole piece has an important significance upon lithium ion battery quality and service life. Also, the invention discloses a lithium ion battery comprising the pole piece.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, in particular to a lithium ion battery pole piece and a lithium ion battery including the pole piece. Background technique [0002] When the anode expansion caused by charging and discharging of lithium-ion batteries accumulates to a certain extent, the appearance of the battery cells will be deformed, and voids will be formed inside the bare cells, resulting in insufficient electrolyte volume, which will induce a chain deterioration of the electrochemical performance of the battery and shorten the life of the lithium-ion batteries. battery life. [0003] In order to suppress the expansion of the anode, a binder with strong cohesive force can be used to restrain the volume expansion of graphite particles after intercalation of lithium; The pole piece and separator are firmly bonded together to enhance its ability to resist deformation. In addition, there are ways to limit the expa...

AI Technical Summary

Problems solved by technology

[0004] Although the above method can alleviate the adverse effects caused by anode expansion to a certain extent, its focus is on the anode pole piece, and the cathode pole piece, another important component of the lithium-ion battery winding structure, is not considered; Non-volatile adhesives can easily cause the pole piece to become brittle, which is not conducive to the subsequent winding process; adding an adhesive coating on the surface of the separator will increase the cost

[0005] The cross-sectional structure diagram of the pole piece (including the cathode pole piece and the anode pole piece) in the prior art is as follows figure 1 As shown, it includes a current collector 10 and an active material layer 20 coated on the surface of the current collector 10, wherein the surface of the active material layer 20 is flat and smooth, and the cathode sheet, the separator and the anode sheet are wound into a bare When the cell is assembled into a battery, the anode sheet is prone to expand, but the opposite cathode sheet cannot restrict it, which eventually leads to the expansion of the entire bare cell

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