just to let you know...the AW CR123a batteries already have a fuse of sorts...it's called a PTC module in addition to it's PCB..well they don't call it a fuse but here's the write up about them:
- New Anti-expolsion Vent/PTC Module : the new module provides an added layer of protection against gas built-up in addition to the PTC thermal protection. Unlike regular vents used by most LiIon cells, these new modules will actually stop the action by separating the electrodes inside the battery when the pressure reaches a preset threshold. The vent disc will open and release the gas plus stopping the cell from further chemical reaction. Combined with the PCB electronic protection and two layers of mechanical ( thermal and pressure ) protection, these new protected R123s are the first with these added safey features in place.
Granted from what I'm seeing it's only in the R123 size..but I'd imagine that they'll expand them to their other sizes at some point