LIA NEWS


NEWS FROM LIA E


Opportunities for fibre


-mobility is continually in the headlines and represents one of the great predicted mega trends for the next decade. Te rationale is clear – the world needs to break


its dependency on fossil fuels and electric vehicles offer the obvious solution. Predictions suggest that by the mid-2030s electric vehicles will be outselling petrol/diesel models. From a manufacturing perspective, this is a paradigm shiſt from combustion engines to electric motors. Passenger vehicles can be either plug-in hybrid vehicles (PHEV) or battery electric vehicles (BEV), both of which need batteries and electric motors. Te manufacturing of batteries and electric motors must undergo a transformation to match the forecasted growth in volume, accompanied by dramatic improvements in cost, yield and throughput. Fortunately, today’s industrial lasers are the ideal tools for the manufacture of key components in both batteries and motors; this has stimulated a significant rise in demand, particularly for fibre lasers.


Cutting of lithium-ion coated foil electrodes Breaking down the key requirements in terms of opportunities for lasers, we can start with the individual lithium-ion battery cells. Tese are made up of layers of coated anodes/cathodes made from thin aluminium/copper foils (above leſt) used in both cylindrical and prismatic cell designs. Te first step where lasers can be involved is in the cutting of the electrodes. Traditionally this has been done using mechanical cutting/stamping techniques, but there is a significant swing to the use of lasers for this process, due to their more efficient speed, lower cost and higher quality. Quality is key and there are stringent


requirements on aspects such as burr formation, delamination, particle debris formation and heat-affected zone. Single mode CW fibre lasers can be used very effectively for the cutting of bare


www.lasersystemseurope.com | @lasersystemsmag


lasers in e-mobility Dr Jack Gabzdyl and Dr Ken Dzurko, of SPI Lasers, highlight the multiple applications that fibre lasers can be used in making electric vehicles


Copper anode and aluminium cathode foils, coated with lithium ion compound, demand high cutting speed and near perfect edge quality to replace punch press machines and render components that can be tightly packed without electrical leakage


foils, but may not be the best choice for the cutting of coated electrodes. Here, nanosecond pulsed fibre lasers excel as the short, high-peak power pulses can cut at high speeds, with today’s 200W sources. SPI’s EP-Z model can reach cutting speeds greater than 1m/s with appropriate cut edge quality. Tere are parallel developments looking at alternative sources, such as green and even ultrafast picosecond lasers with the promise of higher quality, but the reality is that this comes at a cost, which is in direct conflict with the prime driver for manufacturers looking to increase speed and reduce total cost.


Tab welding and bus bar welding of battery packs Within the cell manufacturing process there are numerous opportunities in which lasers are being considered, including welding, cleaning and drilling. Whether they are cylindrical or


Battery tab welding using nanosecond lasers achieves high strength and electrical conductivity without overpenetration. Thin metals and contained electrolytes under pressure make this a demanding application


prismatic cells, these self-contained modules need to be assembled into battery packs where copper or aluminium bus bars are welded to the cells. Te thickness and types of materials vary quite


considerably, but these welds are, in general, quite challenging. Tey rely on welding highly reflective and conductive materials, such as copper or aluminium, either to similar or dissimilar material combinations; the latter being a process that is becoming increasingly common. Given that there are hundreds, if not thousands, of individual cells that need to be joined in a battery pack for an electric vehicle (EV), these joints need to be of high quality, reliability and repeatability. Requiring good static and fatigue strength,


these joints must provide excellent electrical contact resistance, as the power loss at each joint affects the overall efficiency of the pack.


ISSUE 42 • SPRING 2019 LASER SYSTEMS EUROPE 29


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  |  Page 33  |  Page 34  |  Page 35  |  Page 36