Remote cutting of Li-ion battery electrodes with infrared and green ns-pulsed fibre lasers

Abstract

Thin sheet anode and cathode materials made in composite structures constitute some of the most important components of a Li-ion battery. These materials are currently cut by punching technology, which shows degrading behaviour as the tool wears out. A viable option for Li-ion battery electrode manufacturing is the use of remote laser cutting. However the operation requires fulfilling both productivity and quality aspects to substitute the conventional production method. One of the most critical aspects in quality is the clearance width, which is defined as the extent of the exposed middle layer of the sandwich at the laser cut kerf. This work investigates the quality aspects of laser cutting of Li-ion electrodes when a green fiber laser source (λ=532 nm, τ=1 ns) is used rather than the more traditional infrared (IR) fiber laser source (λ=1064 nm, τ=250 ns). The processing conditions were investigated to reveal the technological feasibility zones. Clearance width was studied within the technological feasibility zones for all the material-laser combinations. Results showed that high productivity criterion is met by the IR system, since cutting speed could reach 30 m/min with 54W average laser power on both anode and cathode. On the other hand, the green laser provided clearance width below 20 µm. In the best case the clearance on anode could be eliminated with the green laser system. Although the maximum cutting speed was 4.5 m/min, upscaling of green laser power can provide required productivity.

Current and future lithium-ion battery manufacturing

“…Demir et al. compared the cutting efficiency and clearance width with different types of laser sources ( Demir and Previtali, 2014 ). The result showed that the infrared fiber laser could reach 30 m/min cutting speed with only 54 W power on both the cathode and anode.…”

“…The laser cutting can achieve a clean edge with less deformation, and the cutting width and efficiency can be controlled by the laser power and scanning speed. Demir et al compared the cutting efficiency and clearance width with different types of laser sources (Demir and Previtali, 2014). The result showed that the infrared fiber laser could reach 30 m/min cutting speed with only 54 W power on both the cathode and anode.…”

Influence of Laser-Generated Cutting Edges on the Electrical Performance of Large Lithium-Ion Pouch Cells

“…For the singulation of an anode (130 µm), with the same collector thickness, an energy density of 560 jcm −2 and an intensity of 50.8 × 10 8 Wcm −2 were needed. This could be attributed to the fact that the number of hits per surface increment of 165 increased the plasma shielding effect, and thus reduced the maximum cutting speed [25].…”

Evaluation of the Separation Process for the Production of Electrode Sheets

“…While the width of the heat‐affected zone essentially depends on the spot size and the intensity distribution, only single‐mode beam sources having a high beam quality can be used to separate the electrodes. Due to the quality of the radiation, the minimum achievable spot size is given which can be achieved by perfect focusing optics and thus also the quality of the cutting process …”

“…Since the wavelength that can be generated is limited by the laser‐active media, in particular, the wavelengths 1070, 1064, 532, and 355 nm are the focus of previous investigations because these can be generated most efficiently …”