Work carried out at TWI on methods of joining dissimilar metals has a significant effect on the performance of battery cells. Battery cells can be connected in parallel, series or indeed both. A parallel combination of cells can supply a higher current (the sum of the currents of the cells) but at the same voltage as a single cell.
Typically metal tabs are welded to the anode and cathode of the cell so that the cells can be connected to each other. A good connection must be maintained between the end connectors and the terminals to ensure good battery performance.
The connection of these cells is typically made using spot welds. Depending on the connection quality, this will have an effect on the overall performance of the battery itself. An alternative method has been explored using friction stir welding (FSW) which has many advantages, one of which maximises the weld and allows good current dissipation. FSW can also join dissimilar metals such as aluminium and copper as shown in the photograph.
For further details contact Paul Burling