Thanks to Engadget for noticing this tech! Panasonic and Sanyo are developing a lithium-ion cell designed to power a home for a week.
The home use storage battery, scheduled for a 2011 release, is a way to store electricity generated from solary batteries that now do not allow long-term storage. The system may also be coupled to a system that tracks electricity usage on the home's TVs. More info from Physorg.com.