Pls do not put Lipo batteries in checked baggage(!!!), and instead, keep them with you in the cabin. Discharged, in fire suppressant bags or not, it doesn't matter, but at least, keep the rest of us safe.
Thanks!
PS: Few corrections to the above post:
Fact 1: If you are flying in a jetliner, the baggage compartment IS pressurized.
Fact 2: The lipo's will not combust, but a cell may overheat, and quickly start a fire with the cells next to it. Very rapidly, the whole compartment could be on fire.
Fact 3: Although baggage compartments are equipped with fire suppressant system, they are likely not entirely effective, and remain every airline pilot's nightmare.
Fact 4: if a fire were to start in the cabin instead, flight attendants are/may be equipped with pizza size fire suppressant bags and trained to contain a lipo fire. Furthermore, the cockpit crew would immediately notified, and execute an emergency descent to the nearest airport. Much quicker to wait for the baggage hold to be on fire!