Sure Fire makes a nifty plastic container that has space for six CR123 batteries and an extra light/reflector module for their lights. It also has a bit of paracord to attach it to your kit or person and seems to be well thought out if somewhat expensive.

Is there a similar container for AA batteries that will keep them all snug safe and dry but ready for use if you suddenly find yourself lost in a cave in Central America (or just with a flat tire and dead EDC flashlight on your local road)?