fuel tank located inside the frame of a portable electronic device. The electronic device includes a fuel cell for powering at least one component belonging to the device. The frame has a hollow area where fuel is stored. One section includes an inlet where fuel is introduced into the hollow storage area, and an outlet for releasing fuel stored in the hollow region to the fuel cell.
This process still seems years away, so don't expect to see any of this in the next few BlackBerry smartphones. One good thing though, RIM obviously believes it does have a future to work toward.
source: USPTO (1), (2) via Engadget