Boeing can no longer dilly dally on the Lithium Ion Battery (LIB) in the 787. As much promise as the LIB gave the 787 over older battery design its impairment of melt down is bringing the whole 787 down on the ground. The advantage and more robust and lighter weight battery is out weight by the protective implementation of the safety measures Boeing has taken in making it safe but has not stopped the failure.
That failure alone is killing the dream and Boeing will have to swallow its pride and go to a heavier option that is available. The whole model is at risk from a temperamental problems that Boeing cannot not resolve even though precautions taken keep it safe in its containment box. A heavier battery system that will not behave like the LIB is needed . I believe Boeing is quickly reaching a transfer to that system and is writing a plan to retro fit its customers aircraft after testing of the new non LIB system. A defeat for Boeing but not loosing the airplane war is more important, Until Boeing or its battery subcontractor can isolate the LIB flaw they should not propagate the installation until a solution is found. It is not know what causes the problem which is more important to Boeing to know while selling more 787. The risk is not retired. Until Boeing retires the the causal risk then it go to plan B.
A weight gain by a plan B battery system can be made up in added empty weight by that heavier system, by trimming more unnecessary weight out of the aircraft as it can.
Boeing has been working the plan B for some time and has nursed the LIB problem along for over a year. It would interesting to note if plan B has already tested on LN005 or 006 by now. That would be a major clue if those aircraft have flown with another type of battery pack.
If Boeing takes on new weight for a new solution, some of that weight could be countered by canceled, by eliminating the containment case no longer needed on an alternative battery. As far as the robust energy provided by the LIB, a plan B battery will need innovative power management for its replacement in order to keep up with the LIB promised performance. A set back, yes but not a game changer. Boeing really needs to address unfinished business by determining what causes the failure of the LIB battery under operation. They should also make sure they could change out the Battery Kit in a 787 with some straight forward inter changeability for the LIB and the plan B Battery both back and forth as a solution could be found within the LIB and airlines could go back to the LIB once root cause is found. A big task, yes. But no more so than hundreds of other new technologies innovated on the Dream liner. A change out is needed for coming forward and backward as the 787 switches to various base systems from the batteries.
I am sure Boeing has reviewed every regretable plan to deal with this irepressable LIB and now needs to put that problem to bed until it is resolved. Boeing can no longer suffer further hang-ups with this feature. I don't know how a plan B battery would affect the all electric 787 systems.