Lithium ion battery cell and preparation method thereof

Abstract

The invention belongs to the technical field of lithium ion batteries, and in particular relates to a lithium ion battery cell which comprises at least two positive electrode plates, at least two negative electrode plates, a first wound membrane and a second wound membrane, wherein the positive electrode plates and the negative electrode plates are mutually overlapped, and the difference of the number of the positive electrode plates and the number of the negative electrode plates is one; the positive electrode plates are arranged at the same side of the first membrane; the negative electrode plates are arranged at the same side of the second membrane; and at the direction from the innermost circle to the outermost circle of the battery cell, the first membrane and the second membrane are alternatively arranged between the adjacent positive electrode plates and the negative electrode plates at intervals. Compared with the prior art, the lithium ion battery cell has the advantages that the parallel connection multiple layers of electrode plates provided by the invention can be used for reducing the internal resistance of the battery cell, thus the polarization is reduced, and the discharging platform is improved; the parallel connection of the electrode plates can be used for improving the high-multiplying-power charging and discharging capability of the battery cell; and because the electrode plates of the battery cell provided by the invention are stacked together, the internal structure is unified, the stress is distributed uniformly, the possibility of deformation is small. In addition, the invention also discloses a preparation method of the battery cell.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, in particular to a lithium ion battery cell and a preparation method thereof. Background technique [0002] As the most representative energy storage device in the field of new energy, lithium-ion batteries occupy an irreplaceable position in the fields of mobile electronics, power batteries and energy storage power stations. Especially in the field of power batteries, there are higher requirements for the high rate charge and discharge performance of batteries. [0003] At present, there are two main methods of cell preparation: winding method and lamination method. Relatively speaking, the winding method is more efficient, but the internal structure of the cell rolled out by the winding method is not uniform, and the stress on different positions of the cell is also different, which causes some thick cells and easy thickness rebound. The battery cell is easily deformed during ch...

AI Technical Summary

Problems solved by technology

The process of this method is relatively complicated, and two thermal compounding is required, and the battery unit must be prepared first, so the efficiency is low

And because of the two-time thermal compounding, the alignment accuracy between the pole piece and the diaphragm, and between the pole pieces is not easy to control

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