We'll have to wait and see the results from Boeing's investigations.
#1 difference between the 787 batteries and the 2012 Zero batteries are the battery chemistries, lithium cobalt oxide (LiCo) vs lithium nickel manganese cobalt oxide (NMC). Speaking generally, LiCo is not an inherently safe chemistry; when properly cared for and used under the correct conditions it is fairly safe, but if it is abused then it can vent or enter thermal runaway. (My general understanding is that either the cobalt or the cobalt oxide is exceedingly reactive and the chemistry is not very stable .. but I'm neither a chemist nor a battery expert, so..)
#2 difference is the battery management. On elmoto
someone posted a link to a whistleblower at Securaplane detailing numerous skipped/bypassed tests and shipped faulty equipment. Securaplane manufactures the battery chargers for the GS Yuasa LiCo battery for the 787. The two 787 fires both seem like they occurred when charging (one on the ground, one in the air) .. the Zero BMS is designed to do the same thing the Securaplane BMS SHOULD have done, disconnect the contactor when an overvoltage condition exists.
Bottom line is that anything can be abused. I have approximately 25 gallons of explosive liquids in my garage now. I'm not unduly worried because I know the risk is minimal .. but under the wrong conditions, gasoline is exceedingly dangerous. Similarly for lithium batteries.
Take a look at the three videos posted by liveforphysics here:http://www.elmoto.net/showthread.php?2166-LiPo-Dreams-Does-Anybody-Else&p=27837&viewfull=1#post27837
Note that you may not want to watch the first two with your wife present, if you're trying to build up a case ; )
The third video shows some abusive testing of a 20 Ah NMC cell. Much like the ones used in our bikes. *cough* You can see another abusive test of another 20 Ah NMC cell here:
Skip to 2:40 for the NMC cell test. Cell has been physically abused and overcharged to 4.46V .. then the tabs are hit with an arc welder. The tabs get hot but nothing terribly exciting happens. Unlike the rest of the video..
LFP is a nut.. he seems to really enjoy abusing cells. But I trust his judgment over what cells are safe and what cells are not.