[Iris7]

The reason the Prius works as well as it does is simple. The battery technology was developed with 100% Japanese Government funding by a consortium headed by Matsushita Electric ("Panasonic" is one of Matsushita's brand names) over a period longer than 15 years and costing some billions of dollars. The patent rights were essentially given to Toyota for free - a Japanese style "stock swap".

Toyota will not allow anyone else to make these batteries or even buy them. Other car manufacturers are out of luck.

[SuziQ]

Toyota will not allow anyone else to make these batteries or even buy them. Other car manufacturers are out of luck.

Toyota may have rights to that specific technology, but that doesn't preclude engineers from continuing to create better batteries.