Weight penalty
There do seem to be some wild figures being mentioned in this thread with regard to weight penalty. What we do know for a fact is that the 8 cells used weigh 22 Kg in total. Now multiply that by whatever factor you have for the existing approved technology subtract 22 and you have the weight penalty.
My fear in this instance is that the very fact of the approval process has in this case led to the use of a fundamentally less safe chemistry because it is already approved for aerospace use. The assumption being that the numerous fires that have occurred with LiCo batteries are down to careless use and this would not happen in aviation.
There can be no doubt that the charging arrangements include individual cell voltage monitoring and temperature monitoring seems most likely.
I think the idea mentioned in a much earlier post of isolating the battery during flight has merit as a wokaround solution. After all these batteries are only a standby and have negligible self discharge rates. So charge the batteries on the ground then switch off charging, continue to monitor cell temp and voltage during flight.