How laser welding is helping to reduce weight in the manufacturing and assembly of batteries for electric vehicles.
One substantial challenge for electric vehicle (EV) manufacturers is that of overall weight, and whilst lightweight materials and composites can play an important role in reducing the weight of the vehicle structure, there is also an increasing use of lightweight aluminium in the current conducting elements of EVs, such as the cables and busbars.
Previously, the use of aluminium has been somewhat restricted due to difficulty in welding using conventional joining technologies. However, recent advances in laser welding have now enabled a greater use of the material for both current-conducting and structural components. Lasers can also be used to weld dissimilar materials with varying fusion temperatures, such as steel-copper, steel-aluminium, aluminium-copper, and steel-nickel. These interconnections are essential for many battery manufacturing applications and are made possible by the variety of laser wavelengths.
Laser welding
The laser welding process delivers precise, measured and localised heat input during the joining of various components. The technique’s advanced process control and consistency makes it possible to achieve 100% ‘good welds’.
The various cell types – cylindrical, pouch and prismatic – used in the manufacture of EV batteries all need to be connected by busbars to form a battery module. When creating electrical connections, the joint must have low electrical resistance in order to minimise energy loss through resistance and resultant thermal heating. The size of a weld has a direct effect on this electrical resistance. The use of laser technology makes it possible to produce welds which consistently meet manufacturing specifications and which are also of uniform size. Additionally, the precision of the weld location and weld depth penetration are critical factors.
The materials used to manufacture battery modules, whether for the busbar or the battery cells, are sensitive to imperfections. Any imperfections to these materials as a result of the welding process could negatively affect the electrical performance of the battery module and ultimately the EV itself. Being a non-contact process, laser welding eliminates the risks associated with traditional methods such as resistance welding when it comes to imperfections.
Improving productivity
By implementing laser welding processes, such as those provided by laser technology and service provider TLM Laser, EV battery manufacturers can expect improved productivity over conventional processes due to the technique’s high uptime, reliability and on-demand availability. Further, the ability to be able to re-programme weld positions and parameters to cater for different product variants or module designs ensures futureproofing of the initial capital investment in the technology.
Initially providing a ‘Total Laser Maintenance’ service, TLM Laser now offers a complete range of laser products from some of the leading names in laser technology, such as FOBA, Innolas, Univet, Evosys, 4JET, Universal, BOFA, Univet, ALPHA LASER, LasX, Carveco and IPG Photonics.
Not only does laser welding offer productivity gains to manufacturers, but it also allows them to incorporate greater quantities of materials such as aluminium which offer significant lightweighting potential for battery packs and modules.
