Publications Details
The role of separators in lithium-ion cell safety
Christopher J. Orendorff shares his views on the role of separators in lithium-ion cell safety. One of the most critically important cell components to ensure cell safety is the separator, which is a thin porous membrane that physically separates the anode and cathode. The main function of the separator is to prevent physical contact between the anode and cathode, while facilitating ion transport in the cell. The challenge with designing safe battery separators is the trade-off between mechanical robustness and porosity/transport properties. Most commercially available nonaqueous lithium-ion separators designed for small batteries are single layer made of polyoleins. Many of the multilayer separators are designed with a shutdown feature where two of the layers have different phase transition temperatures. The lower melting component melts and fills the pores of the other solid layer and stops ion transport and current low in the cell, as the temperature of a cell increases.