Although the exact mechanism is still not entirely understood, it turns out that illuminating the liquid crystal, applying a voltage across a small region of it, and then turning off the light source causes a small amount of charge to be stored in that region.
According to the Seattle Times, the fix also involves using a system of venting tubes that in case of an incident would channel any flammable vapours or liquids directly out of the plane, and continuous monitoring of the temperature and voltage of individual cells within the battery.