Laser Welding of Copper

Why Copper is Important :

With the recent norms and growing demands for Electric vehicles, the requirement of batteries is increasing. Copper being a good conductor finds multiple uses in batteries, hairpins, electrical contacts  etc. Copper bus bars , strips etc are used to connect numerous batteries in parallel to get optimum output. Laser welding gives good weld strength, ideal penetration and keeps resistance at joints minimum which makes it an ideal solution for battery welding. Similarly hairpin welding  for electric drive motors has very stringent requirements which can be fulfilled with laser welding.

Why Copper welding is Challenging:

Welding of copper is a  very challenging task because of the following reasons:

• Copper has a very high conductivity and it is a highly reflective material.
• It reflects most of the heat incident on it, and while other metals absorb heat incident on them which leads to rise in their temperature causing them to melt, most of the heat incident on Copper is given away through conduction.
• Therefore, to raise the temperature of Copper to a certain limit to melt it, a lot of energy is required.
• Also when it melts, the melt pool is not stable, so the  weld achieved is not very good in terms of appearance, spatters and porosity..

Advantage of laser welding of copper:

• Lasers offer a very precise and concentrated source of energy to weld copper.
• Particularly all these problems above can be solved to a large extent by a new Blue Laser technology.
• Blue lasers emit light in the ultraviolet range of 400-450nm. This wavelength is most suitable for absorption in copper.
• The absorption of blue light by Copper is much higher than infrared and green wavelengths.(by approximately 50%).
• The molten pool formed by the blue laser is stable and homogeneous and free of any defects. It results in superior weld quality. Also, no / very very less spatters are formed.
• This comes with an added advantage that it can be done on any type of surface. Even if the copper workpiece has been etched, oxidized or brushed, we still get the desirable properties of the weld.
• The process is fast , repeatable and can be automated which can meet the growing demand in  industry for copper welding.

Any query? Feel free to contact us.