Fires on jets aren't exactly an uncommon issue. It's an engineering problem more than anything, with many possible solutions. Apart from the obvious one of designing the pack to minimise short-circuits, you can:
- keep the pack under nitrogen or silicon oil to prevent oxygen exposure
- put the pack(s) somewhere where a fire wouldn't be catastrophic (e.g. mounted as pods out on the wings, like the existing jets)
- make them highly modular, so that problematic cells can be rapidly isolated before serious problems develop.
