Hi,
Ranger One:
For the Main battery the task is much more complex than for the APU batt.
Second, where would you PUT the damn things? Any alternative battery technology will not have the same energy density as lithium. Not only will batteries of equivalent capacity be heavier, they'll be bulkier. Much bulkier. They won't fit in the space available, the space Boeing carved out for lithium batteries. Mk 1 posted on this a few posts back.
Suppose 2 Ni cdīs in two adjacent positions. Could solve the problem you mention.
How much? Letīs quantify?
They would have to reengineer the structure of the EE bay - or even carve a separate battery compartment out of the hold spaces. Now you have structural engineering changes to design, test, certify, put into the production process, and retrofit to the units already delivered. And do this while synchronized swimming with all those subcontractors you've parceled the project out to...
Even optimizing (if possible like i am suggesting) would take months.
Now do you see why I said this airplane isn't going anywhere soon?
Problem is not just a BAD battery. There are MANY PROBLEMS. They yet know. We in pprune (with scarce information) detected SEVERAL.
(the alternative - finding the root of the problem and proving lithium safe enough to use, all over again, could be even harder...)
I agree. And the consistency of this point certainly was taken into account by Chicago Boeing guys (most engineers are not there) in the Decision Making.
Boeing (airplanes) is now absolutely optmizing $. The dream is over. $ is the (only) name of the game. Insurance cover grounding. Further comments can be left to other posts...
They are facing other important problems. 