Hypothetical Battery Upgrade

I just read a review of the plug in prii that toyota are road testing.
According to the article Toyota has installed a second battery in parralel to the first battery .
The review quoted 70+mpg and 130+ horsepower because of this
I prssume this second battery is the same as the first and that it would have its own ecu to control it.
I wonder if the MFD shows 2 batterys or just one

Nick

 

How would a second battery add horsepower? Parallel batteries = same voltage as only one battery... just lasts longer.

 

more current
If I have done my reading correctly the prius has a 50 Kw motor that is limited to 23kw by the invertor and the batterys ability to supply current

Nick

 

Thanks for the clarification.