Battery is the heart of an Electric Vehicle. However, it is the battery that comprises the most precious technology of an EV.
High-power EV battery is a combination of cells in series or parallel to achieve voltage ratings approaching 400V. The demand of connecting individual cells of about 1.5 to 2.0V requires a material good at both conducting and insulating rather than typically insulated cables.
And that effective material called BUSBAR – an electric conductor and ground plane separated by an insulator.
The conventional cell connections (welded wires, strips, or lugs) are susceptible to failure when the cells even slightly dislocate during operation, for example, due to the vibration of a moving vehicle. That is why new interconnection techniques using different busbar solutions have been introduced to overcome these challenges, especially for cylindrical cells.
BENEFITS OF BUSBAR IN EV BATTERY APPLICATION
We could summarize the main benefits of BUSBAR over traditional insulated cables as follows:
Mechanical Capacity
Size & weight – the lower size & weight, the better for car performance.
Size/cross-section sized to meet maximum current carrying possibilities.
Rigidity – keeping the integrity of assembly (battery module/pack).
Flexibility – coping with elastic, thermal & G forces.
Service & maintenance – enabling safe & quick components replacement.
Electrical Capacity
The battery pack design has to ensure proper electrical connectivity.
Conductive material choice: aluminum or/and copper – the risk of galvanic corrosion.
High voltage battery cells and packs (up to 1500V DC) to lower the current – impact on the clearance and creepage distances – electrical insulation.
Thermal Management Capacity
Reduce electrical loss that generates heat at connection points along with connector – busbar.
Assist thermal management task and connections either from the top and bottom in both airbase and liquid coolant based cooling system
Electrical cell connection is an essential element of the battery pack design and the selection of the busbar for the battery call is not always as simple as one might think.
