litium ion battery

I saw this post about Panasonic's home battery. The claim is that this will lead a battery that can power a house for a week. I wonder if I can estimate how big this battery would be. First - to estimate the energy a house consumes. My first approximation is that you could probably run a house off of a 5000 Watt generator, but this probably isn't the average power use for a house. It is probably lower. I am going to go with an estimate of 2000 Watts as the average power over 1 day. How much energy would this be for 1 week? The article above claims that it is a lithium ion battery.…