For cylindrical cell connections, Nickel is the perfect material of choice used in the battery industry.
As per International Annealed Copper Standard (IACS),
- Conductivity of Copper is 100/100
- Conductivity of Aluminium (6061) is 43/100
- Conductivity of Nickel is 23/100
COPPER being a great conductor with affordable pricing, is being explored widely in battery applications by plating it with Nickel or Tin to avoid oxidation.
So, The question that many EV companies and Battery Manufacturers are exploring is:
“CAN COPPER BE WELDED DIRECTLY TO CYLINDRICAL CELLS FOR HIGHER CURRENT APPLICATIONS?”
LASER WELDING comes into picture, when Resistance Welding Technology fails to weld conductive and thicker strips.
At Light Mechanics Ltd we have successfully welded 0.15mm Cu strip with Ni plating to 21700 Cylindrical Cell.
The peel off test showed the weld strength of 92 Newtons.
During destructive testing, the copper strip broke with the weld nugget still remaining intact.
LASER WELDING is a technology which has to be mastered!
If too little welding energy is applied, the connection lacks mechanical stability.
If too much energy is applied, the battery mode of operation is impaired leading to shortened life.
- The ENERGY input needs to be just PERFECT…
- The LASER chosen has to be just RIGHT…
- The PARAMETERS has to be CORRECT…
- And any welding can be made POSSIBLE!