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

Abstract

To improve the battery performance of lithium-ion batteries (LIBs), modifying the anodes and cathodes of LIBs using laser beams to prepare through-holes, nonthrough-holes or ditches in the arrangements of grid and line patterns has been proposed by many researchers and engineers. In this study, a laser system with a roll-to-roll machine, which realizes this modification without large changes in the present mass-production system, was developed. The laser system apparatus comprises a roll-to-roll system in which a hollow cylindrical body with openings on a circumferential surface is the main part and laser equipment is attached. A foil of thin electrode for LIBs is wound around the cylindrical body in the longitudinal direction of the thin electrode. The pulsed beam reflected from a central axis of the cylindrical body can continuously open a large number of through-holes in the thin electrode. The through-holes were formed at a rate of 100000 holes per second on the lithium iron phosphate (LiFePO4, LFP) cathodes and graphite anodes used in this study. The through-holed cathode and anode prepared with this system exhibited higher C-rate performance than nonholed (nontreated) anodes and cathodes.

Improvement in Rate Capabilities of Hybrid Cathodes with Through‐Holed Layers of Cathode Material and Activated Carbon on Each Side of a Current Collector in Lithium‐Ion Batteries.

“…The cross-sections of the LFP/AC and NMC/AC HCs were obtained with FE-SEM (Figure 5). Similar to the through-holed LFP/AC HC and LFP/LFP cathodes shown in our papers [13][14][15] and as expected from the surface SEM image of through-holed LFP/AC and NMC/AC HCs in Figures 3 and 4, the cross-sectional shapes of holes formed on the side of laser incidence was mortar-shaped; the smallest hole size was at the position of the CCs. The degree of the tapered shape was different between the LFP/AC and NMC/AC HCs.…”

“…The details of the preparation method of the cathode material and AC layers on the CC are described in our past papers. [13,15] The total loading amount of LIB cathode material and AC coated on an Al CC sheet (34 mm × 20 mm) was 5.9 mg. The weight of 5.9 mg was divided into the weights of the LIB cathode material and AC materials to prepare HCs with different weight percentages of AC relative to the total weight of the active materials.…”

“…As described previously, [13,15] a picosecond pulsed laser of RGH-532-8 (Rayture Systems Co., Ltd) was applied for drilling the surfaces of the HCs. The laser beam was incident to the HC from the side of the cathode material layer, and it penetrated the AC layer side.…”

Optimizing Fast Charging and Wetting in Lithium-Ion Batteries with Optimal Microstructure Patterns Identified by Genetic Algorithm

“…12 Chen et al, also demonstrated this new manufacturing technique for industrially relevant cell format (>2 Ah pouch cells). 13 Direct laser interference patterning 14 and laser in hollow cylinders 15 have been also demonstrated in a roll-to-roll system, respectively, with web speed of 1.3 m min −1 with a web width of 150 mm and 2.6 m min −1 with a web width of 120 mm. Additionally, laser ablation offers relative fine control of the channel geometry, which is essential to maintain manufacturing uniformity.…”

Benefits of Femtosecond Laser 40 MHz Burst Mode for Li-Ion Battery Electrode Structuring

“…Depending on the process and technology, this speed ranges from 25 to 300 m/min [12]. Currently, using a roll-to-roll machine [13], a line speed up to 5 m/s for drilling [14] and 10 m/s for grooving [15] were reported. Therefore, significant progress should be achieved to match the industrial requirements.…”