Winding type cell

Abstract

The invention relates to the field of a secondary battery, and specifically to a winding type cell. The winding type cell comprises a flat-shaped cell which is formed by a first diaphragm, a first pole piece, a second diaphragm and a second pole piece which are laminated in sequence in a winding manner; a hollow foil region is arranged at the head of the first pole piece, and is electrically connected with a first tab; a hollow foil region is arranged at the head of the second pole piece, and is electrically connected with a second tab; the center line of the flat-shaped cell in the width direction is the neutral line of the cell; the site where the first pole piece is bent for the first time is a first bending position; a line which passes through the first bending position and is parallel to the neutral line of the cell is a first bending line; the starting end of the first pole piece is the first starting end; the starting end of the first diaphragm and the starting end of the second diaphragm are positioned between the first starting end and the second tab; and the distance from the first starting end to the first bending line is less than that from the second tab to the first bending line. By adoption of the winding type cell provided by the invention, the usage amount of the diaphragm can be reduced, the energy density can be increased, and the cost can be lowered.

Description

technical field [0001] The present application relates to the field of secondary batteries, in particular, to a winding battery core. Background technique [0002] At present, secondary batteries widely used in the market are composed of battery cells and casings of secondary batteries. Among them, the battery core is an active component, and is generally formed by laminating or winding a positive pole piece, a negative pole piece, and a separator arranged between the positive pole piece and the negative pole piece. The positive electrode sheet includes a positive electrode collector and a positive electrode active material coated on the surface of the positive electrode collector; the negative electrode sheet includes a negative electrode collector and a negative electrode active material coated on the surface of the negative electrode collector. [0003] With the development of commercialization of secondary batteries, the market has higher and higher requirements for the...

AI Technical Summary

Problems solved by technology

However, these solutions are currently limited by the material itself or processing, and further improvement is becoming more and more difficult, and may bring high costs or high risks.

[0004] In the current traditional winding method, such as figure 1 and figure 2 As shown, the inside of the winding cell needs to be empty with a layer of isolation film. There are 4 layers of isolation film stacked continuously on the innermost side of the cell, which not only causes waste of the isolation film, but also increases the thickness of the cell to reduce the energy density of the cell.

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