Lithium ion battery liquid injection method and lithium ion battery

Abstract

The invention belongs to the technical field of lithium ion batteries, and particularly relates to a lithium ion battery liquid injection method which comprises the following steps: putting a baked battery into liquid injection equipment; vacuumizing the liquid injection equipment at first, and then vacuumizing the interior of the battery; injecting an electrolyte into the battery, and sealing; clamping the battery by using a battery clamp to ensure that the battery clamp is in good contact with the battery; and enabling the battery clamp to drive the battery to turn over, so that the electrolyte infiltrates a pole piece and a diaphragm. According to the liquid injection method of the lithium ion battery provided by the invention, the battery clamp is heated in advance, and the battery after liquid injection is clamped by the battery clamp to turn over, so that the viscosity of the electrolyte is reduced, the flowability is enhanced, the infiltration is facilitated, and the infiltration efficiency of the electrolyte to the pole piece and the diaphragm is improved. By adopting the method disclosed by the invention, the battery can be infiltrated by the electrolyte as soon as possible, and the standing time is shortened to be within 4 hours at normal temperature and is saved by 20 hours compared with the prior art.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a liquid injection method for a lithium ion battery and a lithium ion battery. Background technique [0002] The lithium-ion battery preparation process generally needs to go through the processes of packaging, baking, liquid injection, standing, forming, fixture shaping, second sealing and volume separation. [0003] In the production process of commercial lithium-ion batteries, after the liquid injection process is completed, the battery is left to stand for a period of time to ensure that the electrolyte is fully infiltrated in the pole pieces, and the formation process can only be carried out after the infiltration is completed. If the electrolyte is poorly infiltrated, a part of the electrode active material is not in contact with the electrolyte and cannot be used effectively, which will cause problems such as accelerated decay of battery life. Th...

AI Technical Summary

Problems solved by technology

The negative electrode active material is usually graphite, which has low hardness. Increasing the compaction density of the pole piece will lead to plastic deformation of the material particles, which will affect the internal pore structure and distribution of the pole piece.

Therefore, it is often more difficult for the electrolyte to infiltrate the negative electrode than the positive electrode, and the poorly infiltrated negative electrode usually has black spots and lithium precipitation during the battery cycle, which will lead to accelerated decay of the battery cycle life and bring to safety hazard

In addition, the gas remaining in the battery structure will also hinder the infiltration of the electrolyte, the pole piece and the diaphragm, and cannot effectively improve the fluidity of the electrolyte, and cannot make the electrolyte penetrate deeply into the battery

[0004] In the existing technology, the battery enters the static state directly after liquid injection is completed. The current static time is 24 hours at high temperature or 48 hours at room temperature. It is relatively slow for the electrolyte to completely infiltrate the pole pieces, resulting in long production hours and low production efficiency.