Lithium Ion Battery with Built-In Flame Suppression

Stanford University electrochemical researchers have created a lithium-ion battery with built-in flame suppression. An integrated flame retardant is released once the battery reaches 160 degrees Celsius, its critical temperature, and the flames are doused within a second. Miraculously the addition of an integrated flame retardant doesn't reduce battery performance.

A major weakness of the lithium-ion batteries is that they contain a highly flammable electrolyte. Thermal runaway can occur when a Li-ion battery suffers physical damage or possibly a fault in the charging/discharging circuit. If thermal runaway is achieved, the result is usually a very large fire, sometimes followed by an explosion.

By creating a new separator, researchers have provided a workable solution to the problem. The new separator, a semipermeable membrane between the negative and positive sides of the battery, contains a flame retardant and replaces the commonly used polymer separator.

When the separator hits 160 degrees Celsius, the polymer melts, abruptly releasing the TPP into the electrolyte and extinguishing the combustion. In the above image the separator is doused with electrolyte, set on fire, and then the TPP is released within 0.4 seconds, extinguishing the flame. The new separator is flexible, strong, and doesn't seem to affect long-term battery performance.