ULTRASHORT LASER PROCESSING


SELECTIVE ULTRASHORT PULSE LASER PROCESSING OF BATTERY ELECTRODES


NAZANIN MIRHOSSEINI ET AL.*


Lithium-ion batteries (LIBs) underpin global electrification, with demand reaching 460–500 GWh in 2021 and projected to grow by 30–40% annually, driven primarily by electromobility [1]. Despite major advances since the 1990s, LIBs continue to face limitations in energy density, charging speed, safety, and manufacturability, particularly for heavy-duty and long-range systems [1,2]. Manufacturing quality is increasingly recognised as a key bottleneck, with materials accounting for up to 75% of total cell cost, making scrap reduction and process efficiency critical as raw material prices rise [3].


Electrode cutting is a particularly sensitive step, as defects, debris, or delamination can trigger internal short circuits and compromise safety [1]. Mechanical punching remains the industrial standard due to its high throughput, but tool wear—especially for ceramic-coated electrodes—leads to deteriorating cut quality and frequent maintenance [1]. Laser-based processing offers a flexible, tool-free alternative, but continuous-wave and nanosecond lasers often cause thermal damage in modern multi-material stacks [4], while ultrashort-pulse lasers enable cleaner cutting with lower damage but must achieve robust, high- throughput performance for industrial adoption [5].


This article is based on a study that directly compares nanosecond and picosecond laser cutting using a low-power, multi-pass strategy to identify scalable, low-damage processes for next-generation battery manufacturing [6].


MATERIALS AND METHOD


TEST SPECIMENS AND LASER SYSTEMS


Anode (graphite/Cu, 132 µm) and cathode (NMC/Al, 105 µm) sheets were cut using two UV (355 nm) DPSS laser systems: a 7 ns, 3 W (20–80 kHz) source and a 10 ps,


24 | LASER USER 119 MARCH 2026


Figure 1: Representative microscope images of electrode cuts using (a,b) the VLASE DPSS laser (2.1 W, 20 kHz) and (c,d) the Edgewave laser (10 W, 400 kHz) on anode and cathode. Scale bar is 100 µm.


Table 1: Anode and cathode material details


Material Function Application


Anode (132 µm thick)


Electrode Composition


Graphite anode material coated on both sides of a copper (8 µm thick) foil


Cathode (105 µm thick)


Li-NiMnCo cathode material coated on both sides of an aluminium (15 µm thick) foil


10 W (400–2000 kHz) source. A low- power multi-pass strategy was used for both systems to enable controlled layer-by-layer removal. More information is given in Tables 1 and 2.


DESIGN OF EXPERIMENTS AND EDGE QUALITY ASSESSMENT


To optimise the picosecond laser cutting process, a structured Design of Experiments (DOE) approach was employed using a Taguchi L4


Table 2: Laser parameter details (ns and ps) VLASE DPSS laser


Wavelength (nm) 355 Pulse duration


Average output power (W)


Beam diameter (µm)


7 ns 3


Frequency (kHz) 20-80 ~ 40


Edgewave DPSS laser


355


10 ps 10


400-2000 ~ 40


(2³) orthogonal array to efficiently evaluate the effects of three key parameters: laser power, pulse spacing (scanning speed/laser frequency), and number of scan passes, on cut quality and process efficiency. This fractional factorial design enabled assessment of factor contributions with a reduced number of experiments, using cut-through, edge defect, and total processing time as the primary output responses.


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32