Please, if you have not already done so, read the eight Special Certification Conditions which were set for use of Li-Ion batteries on the 787
Federal Register, Volume 72 Issue 196 (Thursday, October 11, 2007). Note that the dangers of using Li-Ion are clearly spelled out and prescient.
Note too that pilots (ALPA) were only respondents to NPRM which preceded SCCs. ALPA was adamant that a battery fire was unacceptable; “The intent of our comments submitted to the Docket for question [Special Condition] Number 4 (see below) is to assure that the FAA includes language or makes it clear in the Special Conditions directing the OEM or a potential STC applicant that a fire from these devices, in any situation, is unacceptable. ALPA requests the FAA reiterate that preventing a fire and not reacting to one, if one occurs, is critical”. FAA reassured them; “The FAA shares the commenter's concern over a fire erupting in flight. The regulations and the rigid requirements defined in these special conditions are intended to prevent lithium battery fires on board the aircraft”.
SCCs are not friendly agreements between consenting adults; they are law. 787 cannot fly unless all SCCs are met.