Meaning
Solid interface materials transfer heat away from battery cells toward a cooling plate or heat sink. A pre-cured thermal pad consists of a polymerized elastomer filled with thermally conductive particles like aluminum oxide or boron nitride. These pads maintain their shape and thickness under pressure to provide consistent cooling.
Heat Transfer
Conductivity through the pad allows for the management of the cell temperature during high power events. Using a pre-cured thermal pad is an alternative to liquid gap fillers, offering a cleaner application process. The material works by conducting heat from the warm cell surface to the cold plate.
Void Filling
Conformable surfaces allow the pad to fill the microscopic air gaps between the components. While a pre-cured thermal pad is solid, it is soft enough to deform under the assembly load and create a continuous thermal path. This prevents the formation of insulating air pockets that would cause hot spots.
Manufacturers choose the hardness of the pad based on the expected tolerances of the battery module parts. A softer pad provides better contact but may be more difficult to handle in high volume production lines.
Interface Durability
Stability over the lifetime of the vehicle is a requirement for these materials. A pre-cured thermal pad does not dry out or pump out from the interface during thermal cycling. This ensures that the cooling performance remains unchanged for the entire service life of the pack.
