Development of a roll-to-roll high-speed laser micro processing machine for preparing through-holed anodes and cathodes of lithium-ion batteries

Abstract

Aiming to improve the battery performance of lithium-ion batteries (LIBs), modification of the cathodes and anodes of LIBs using laser beams to prepare through-holes, non-through-holes or ditches arranged in grid and line patterns has been proposed by many researchers and engineers. In this study, a laser processing system attached to rollers, which realizes this modification without large changes in the present mass-production system, was developed. The laser system apparatus comprises roll-to-roll equipment and laser equipment. The roll-to-roll equipment mainly consists of a hollow cylinder with openings on its circumferential surface. Cathode and anode electrodes for LIBs are wound around the cylinder in the longitudinal direction of the electrodes. A pulsed beam reflected from the central axis of the cylinder can continuously open a large number of through-holes in the thin electrodes. Through-holes were formed at a rate of 100 000 holes per second on lithium iron phosphate cathodes and graphite anodes with this system. The through-holed cathodes and anodes prepared with this system exhibited higher C-rate performance than nontreated cathodes and anodes.

Keywords

• lithium-ion batteries
• laser processing system
• roll-to-roll system
• through-holing structure
• high-rate performance