Ian W
How about...
1. Overcharging
In general, lithium ion batteries are significantly more susceptible to internal failures that can result in self- sustaining increases in temperature and pressure (thermal runaway) than their nickel-cadmium or lead-acid counterparts. This is especially true for overcharging, which causes heating and destabilization of the components of the cell, leading to formation (by plating) of highly unstable metallic lithium. The metallic lithium can ignite, resulting in a self-sustaining fire or explosion. Finally, the severity of thermal runaway from overcharging increases with increasing battery capacity, because of the higher amount of electrolytes in large batteries.
"We may never know the cause..."
The cause is part of the problem, known since the advent of the technology. Given "mystery" how can anyone in their right mind propose a "fix"?
Without
eliminating each possible cause, one is left with a known fire, of unknown origin...
So at least in service to the regs, and the English language, absent a known cause, there is no "fix", interim, permanent, or otherwise.
Only a "method to control spread of fire"....
