Heat transfer is the key to provide high performance and durability of battery packs. Forced Air cooling and Indirect Liquid cooling are inefficient methods and are not satisfactory when the performance of the battery pack needs to be high, in terms of power-to-energy ratio. The solution is direct liquid cooling, using dielectric fluids and placing them directly in contact with the conductive zones where electricity flows.

The Project for ‘Raffreddamento a liquido diretto’ CUP: F88I23000580006 was realised with the contribution of the European Regional Development Fund.

FCE has developed a design that allows direct cooling of the cell poles by dielectric fluid, a method 5 times more efficient than cooling the side surface of the cell body. Displayed here in the video is FCE patented method.

There is a mistaken belief that the presence of a dielectric fluid in direct contact with cells can be risky in case of short circuits and thermal runaway of cells. In fact, the presence of a liquid directly in contact with the cells greatly lowers the risk of fire in a module with lithium-ion batteries. The following video shows a nail penetration test comparing a module with cells in air (left in the video) and a module with cells wetted directly by a dielectric fluid in contact with the poles. The result is a reduction of more than 100°C in maximum cell temperatures and immediate extinction of thermal runaway by the dielectric fluid. The graph of cell temperatures in the two cases, compared, follows.