Method used for avoiding lithium battery coil core diaphragm black points

Abstract

The invention relates to a method used for avoiding lithium battery coil core diaphragm black points. The method comprises following steps: in lithium battery sheet production process, laser is adopted for cutting of electrode sheets so as to form a mark hole position used for identifying an electrode sheet cutting position; before coiling, the mark hole position is subjected to primary cutting, the electrode sheet is moved to be b away from the cutting position, and at the new electrode sheet cutting position, the two surfaces of the electrode sheet are provided with protective adhesive tapesymmetrically so as to connect the cut electrode sheet to be one body; in coiling, the protective adhesive tape on the electrode sheet is subjected to secondary cutting, after secondary cutting, the electrode sheet and a diaphragm are coiled so as to form a coil core, and high voltage short circuit is adopted to detect whether short circuit of the coil core is caused. The method is capable of solving a problem in the prior art that diaphragm black points are generated because of high voltage short circuit detection, and electrode sheet cutting powder shedding, and improving the safety performance of lithium batteries.

Description

technical field [0001] The invention relates to the technical field of lithium battery production, in particular to a method for eliminating black spots on lithium battery winding core diaphragms. Background technique [0002] The production process of lithium batteries is long and complicated, and generally includes a series of processes such as slurry mixing, coating, roll cutting, sheet production, winding, assembly, laser welding, baking, liquid injection, formation, and volume separation. Among them, after the pole piece and diaphragm are wound to form a core, a high-voltage short-circuit tester or a high-voltage internal resistance tester will be used to test whether the core is short-circuited by hot pressing. [0003] Since the materials used in lithium batteries are all micron or even nano-sized, if the production process is not well controlled, the lithium battery pole piece is easy to lose powder during the winding and cutting process, especially for the continuou...

AI Technical Summary

Problems solved by technology

[0003] Since the materials used in lithium batteries are all micron or even nano-sized, if the production process is not well controlled, the lithium battery pole piece is easy to lose powder during the winding and cutting process, especially for the continuous coating pole piece production method ;The falling dust is easy to adhere to the surface of the pole piece and the diaphragm due to the electrostatic effect. During the short-circuit detection, the high voltage generated by the short-circuit tester breaks down the dust point, causing a large area of ​​high-temperature carbonization of the diaphragm, resulting in black spots, causing lithium battery The internal short circuit of the winding core brings a greater safety hazard to the use of the battery core in the later stage

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