It seems like the common thread between the bulk of these battery fires is the battery manufacturer---LG Chem. Several other vehicle manufacturers like Kia have had fires with LG batteries. The issue in the past (along with both Bolt issues) appears to be manufacturing defects within the battery itself leading to internal separator failure and the resultant "thermal event". And lets not forget this goes all the way back to the Boeing Dreamliner battery failures which were also a LG module similar to that which was used in the Mitsubishi I-MiEV.