Bartender Inspires Nissan’s Li-ion Battery

In order to pack more charge into the Li-ion battery of the Nissan Leaf electric car, the battery engineers of Nissan Motor Co. has turned to the tap for inspiration.

Their latest breakthrough is topping off the battery with three additional minicharges at five-minute intervals at the end of charging. This bears similarity to an expert bartender waiting for the foam to die down prior to topping off a beer with tap blasts.

Speaking at a conference in Tokyo, Taiichi Onoyama, expert leader at Nissan’s electric and hybrid system engineering department, said that in their company, they talk about extra charging utilizing the example of how to pour beer.

The maneuver crams an additional 0.7 percent of energy into the battery. It is not much, but can make a huge difference in an electric vehicle. The secret lies in enabling the cell voltage to dip a bit between charges, like the foam on a beer. Hence, the lower voltage enables the battery to accept more charge.

It might suggest a slightly longer charging time, but just as Germans don’t mind waiting for a perfectly poured pilsner, most motorists don’t mind the additional charging time for a fully topped-off battery.

Onoyama reported that they have not received any complaints so far.