The German state is offering a buyer incentive in an effort to make electric cars more palatable to consumers. And the car makers are constantly improving the technology and battery capacities.Nissan has introduced a new battery for its Leaf with a capacity of 30 kilowatt hours, extending the car's range from 200 to 250 kilometers on a full charge. The new battery can be filled to 80 percent in just 30 minutes at a quick charging station.