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technical paper
Optimizied Contact Resistance at Bolted Copper Busbars by Means of Ns-Laser Surface Treatment
keywords:
batteries
bus bars
copper
contact resistance
The global mobility and regenerative power revolution is in full swing. Demand for components for electric cars, alternative drives and energy storage is rising continuously.
At the heart of many solutions is the laser. Especially high power and mid power nanosecond Laser for surface treatment in many different applications.
Another field to enhance power efficiency is to avoid electrical losses. One main driver of losses in EV’s or high currant cabinets are screwed busbar connections. State of the art solutions to prevent contact resistances losses are expensive environmental critical coating processes with deformable high conductive metals like nickel. Several papers have shown that mechanical pretreatment of the busbar surface in the interaction zone of screwed joining can lead to a significant drop down of the contact resistance. In our investigation we show that Laser surface treatment is an ideal tool to transfer these results in a highly flexible and productive way.
We will demonstrate with an industrial relevant case study the potential to significantly decrease the contact resistance on screwed connections of copper busbars by means of laser surface treatment.
Therefore, 3 different Laser sources, different treatment strategies were performed. All busbars were screwed and electrically qualified by a calibrated µ-Ohmmeter. The investigation leads to the conclusion, that a tailored laser surface treatment combines highest productivity, lowest contact resistance without any additional coating steps, a long shelf lifetime and highest reproducibility.