Cylindrical lithium ion battery

Abstract

The invention relates to the technical field of lithium ion batteries, in particular to a cylindrical lithium ion battery. The cylindrical lithium ion battery comprises a battery casing, a pole piece group accommodated in the battery casing, electrolyte filled in the battery casing and a cap which is sealed and assembled to the battery casing, wherein the cap comprises a top cover; the circumferential edge of the top cover is outwards bent to form a bent step; an explosion-proof sheet is covered at the bottom of the top cover; and the circumferential edge of the explosion-proof sheet is connected with the bottom of the bent step in a sealing manner. Compared with the prior art, in the cylindrical lithium ion battery disclosed by the invention, the top cover, a rubber ring and the casing in a sealing port participate in sealing connection; and sealing stepped grooves are respectively arranged on the upper surface and the lower surface of the circumferential edge of the top cover, thus the explosion-proof sheet in the sealing port is prevented from being deformed due to stress; a pressure release value of the explosion-proof sheet is prevented from being increased or not being opened by exposing; safety problems such as burning, explosion and the like are reduced; and the stability, the sealing property, safety performances and the capacity space of the cylindrical lithium ion battery are improved.

Description

Technical field: [0001] The invention relates to the technical field of lithium ion batteries, in particular to cylindrical lithium ion batteries. Background technique: [0002] With the development of modern society, mobile devices such as camcorders, notebook computers, portable DVDs and digital cameras have been used more and more widely. Cylindrical lithium-ion batteries, as a green and environmentally friendly battery, have the advantages of high energy density, high operating voltage and long service life, so they are more and more widely used in various mobile devices. [0003] See figure 1 , 2 As shown, the existing cylindrical lithium-ion battery generally includes a battery case 11, a pole piece group 12 with a winding structure, and the pole piece group is composed of a positive pole piece, a negative pole piece and a separator between the positive pole piece and the negative pole piece. The pole piece group 12 with a coiled structure is wound into a battery ca...

AI Technical Summary

Problems solved by technology

Because the support platform formed by the rolling groove is short and not horizontal, during the crimping and sealing process, the cap 13 will move downward due to the downward pressure of the edge of the shell mouth, and the explosion-proof disc 14 component in the cap 13 will be deformed. The common problems caused by the deformation are as follows: 1. It causes the fluctuation and increase of power failure and pressure relief value, and the product flows into the market, which is easy to cause safety hazards; 2. The compression amount of the rubber ring 15 fluctuates, resulting in poor sealing; 3. The component clearance changes, causing resistance fluctuations

Seriously affects the safety performance of cylindrical lithium-ion batteries

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