Small flames were noted in one of the two incidents reported when gases escaping from the battery were ignited by an electrical short-circuit in the presence of ambient oxygen, but that was all external to the battery case.

FORBES: Boeing Completes Tests Leading To Resumption Of Dreamliner Operations

A123 has developed a battery that uses a doped lithium nanophosphate electrode (cathode) that eliminates combustible oxygen from the system.

FORBES: Jump Start