A liquid injection hole sealing structure for a lithium ion battery

Abstract

A liquid injection hole sealing structure for a lithium ion battery is provided. The structure includes a top cover plate, a seal ring and a weldable seal nail. The top cover plate is provided with a liquid injection hole having a straight wall. The seal nail includes a nail body inserted into the liquid injection hole and a nail head welded to the top cover plate. The seal ring is fixed to the nail body of the seal nail and is between the top cover plate and the seal nail. Compared with the prior art, the liquid injection hole sealing structure achieves advantages of easy welding, few welding seam defects, a high production efficiency, easy welding seam detection, and the like through assembling the seal ring and the seal nail into an integrated seal nail.

Description

technical field [0001] The invention belongs to the field of lithium ion batteries, in particular to a sealing structure for a liquid injection hole of a lithium ion battery. Background technique [0002] After the second liquid injection of the lithium-ion battery, in order to ensure the negative pressure environment in the casing to prevent external gas and moisture from entering the battery cell, the liquid injection hole needs to be sealed. The existing sealing process is as follows: use rubber nails for initial sealing, then remove the electrolyte remaining inside and around the step-shaped liquid injection hole through manual cleaning and laser cleaning, and finally assemble the sealing nails and perform laser welding on them. In order to check whether there are defects in the laser welded seam, it is necessary to inject a certain amount of helium gas into the battery before the rubber nail is sealed, and then perform helium inspection after laser welding. [0003] Ho...

AI Technical Summary

Problems solved by technology

[0005] 2) The liquid injection hole must be designed as a step hole for placing rubber nails, resulting in a relatively large diameter of the liquid injection hole and a large circumference of laser welding, which affects production efficiency; in addition, for small-sized batteries, it is also The edge of the liquid injection hole will be closer to the pole and the explosion-proof valve, and the heat and spatter during laser welding will cause deformation and discoloration of the plastic on the pole and the explosion-proof valve;

[0006] 3) Due to the good sealing performance of the rubber nail under the sealing nail, helium gas cannot pass through the rubber nail during the helium inspection, and the sealing of the laser welding part cannot be effectively tested, and the missed weld defects will cause Batteries are a safety risk during long-term use

Images