Nissan tests new Leaf battery chemistry

Nissan believes it can create a longer-lasting battery pack for its electric Leaf next year by altering the recipe used to create the component.

The proposed change in chemical composition, which is still under review at the automaker, should make the lithium ion battery more resilient to hot-weather aging, says Billy Hayes, vice president for Nissan's global electric vehicle business.

"We're working on an improved chemistry to improve the longevity of the batteries, especially in these prolonged extreme heat situations," Hayes told journalists during the Tokyo Motor Show last month.

"We're optimistic that we would use that for replacements going forward."

If approved, the new chemistry would go into production at Nissan's Smyrna, Tenn., Leaf and battery module assembly plant in the first half of 2014, he says.

Leaf owners in hot-weather markets such as Arizona and New Mexico have complained that their batteries appear to be aging faster than the manufacturer envisioned.

This year Nissan addressed the complaints by vowing to replace underperforming batteries.

Hayes says the new chemical composition will not extend the Leaf's driving range, which averages 73 miles on a single charge, according to Nissan marketing material. But he said it should delay the degradation of the battery over its lifetime.

EV batteries are produced in a baking process in which 48 modules of cells are sealed, injected with electrolyte and allowed to age.

Altering the chemicals involved can produce differences in performance, weight, cost and other characteristics.

Andy Palmer, Nissan's chief planning officer, says the Leaf battery has already gone through two other product enhancements since it entered production in Smyrna a year ago, to reduce weight and cost. He estimated that, after the expected change in chemical composition next year, it will likely see two more generations over the next two years.

Meanwhile, Nissan is working on other EV batteries, as well as other battery-powered models, Palmer says. In 2014, Nissan will introduce a lithium-powered NV200 compact cargo van. And Nissan is also studying plans to build an EV sports car based on the recently unveiled BladeGlider concept.