As a chemist, I've seen lithium Grignard reagants just "go" in inert conditions. No free oxygen, but within a carbonyl or alcohol environment.
The only way you can put these kind of fires out is either to use a specialist copper/nitrogen extinguisher, or to use sand to take the energy away.
The only other way to do it would be to pack the batteries with a chemical pack above them to stop the chain reaction, maybe an alkyl amino compound. But can you honestly see shippers paying for the extra weight?