If I remember correctly Apple had a similar problems with its very first iPhones 3, (batteries exploding and catching fire..) very quickly the company found a fix and I have not heard the problem coming back since ( or it is well kept away from news).
So it would look like a technical solution does exists.
For those discussing the way smoke moves inside an aircraft cabin/cockpit , you may want to read through some of the pages of the final report of SR111.