Processing method for reducing self-discharge rate of battery core

Abstract

The invention provides a processing method for reducing the self-discharge rate of a battery core. The processing method comprises the following steps: (1) a packaging bag of positive pole powder of a lithium ion battery is opened; (2) filtration is implemented, namely the positive pole powder of the lithium ion battery is arranged inside a vibrating screen, and is vibrated and filtrated for 30 minutes to 1 hour, so that large-particle impurities are removed; (3) filtration is implemented, namely the positive pole powder of the lithium ion battery, which is filtered by the vibrating screen, is arranged inside a magnet filter, a vibrator is started to remove magnetic impurities, a PVC bag is connected with an outlet of the magnet filter, the powder is collected by the PVC bag, and the powder is packaged and is subjected to the next procedure; (4) the magnetic impurities adsorbed on the magnet filter are cleaned away. 99.9% of magnetic metal impurities in the positive pole powder can be removed by adopting the method, and the self-discharge rate of the battery core is reduced, and therefore the product qualification rate is improved.

Description

technical field [0001] The invention relates to a treatment method for reducing the self-discharge rate of battery cells, which belongs to the field of lithium batteries. Background technique [0002] Cylindrical 18650 lithium-ion secondary batteries with high rate performance are widely used in electric bicycles, electric vehicles, power tools, mining safety warehouse backup power and other fields. The demand is large. Battery self-discharge refers to the phenomenon that the battery drops when the battery is left standing in an open circuit , compared with Ni-Cd and Ni-MH batteries, the self-discharge of lithium-ion batteries is negligible, but still relatively large, and the dependence on temperature is relatively large, in LiMn 2 o 4 、LiCoO 2 and LiNiO 2 In the electrode, the phenomenon of self-discharge is inevitable, and the degree of self-discharge depends on the preparation process of the positive electrode and the battery, the properties of the electrolyte, the st...

AI Technical Summary

Problems solved by technology

[0003] The irreversible reaction caused by the micro-short circuit caused by impurities during manufacture is the most important reason for the large self-discharge of individual batteries. The dust in the air or the metal powder on the pole piece and diaphragm during manufacture will cause Micro-short circuit, absolute dust-free production is impossible. When the dust is not enough to pierce the diaphragm and short-circuit the positive and negative electrodes, it will have little impact on the battery; but when the dust is serious enough to pierce the diaphragm When the "degree" is reached, the impact on the battery will be very obvious. Due to the existence of the "degree" of whether the diaphragm is pierced or not, when testing the self-discharge rate of a large number of batteries, it is often found that the self-discharge rate of most batteries is concentrated in the In a small range, only a small part of the battery self-discharge is obviously high and the distribution is discrete. These should be the batteries with the diaphragm pierced. Nowadays, various fields have high requirements for the consistency of batteries. The fatal flaw of consistency, the self-discharge of the battery directly reduces the service life of the battery pack