Nissan is testing a revised lithium-ion cell chemistry for its Leaf electric car that the company says appears to be as durable in sustained extreme heat as its current battery is under normal conditions.
If tests confirm that the new cells degrade at no more than the standard rate, even at high temperatures, the company hopes to have battery packs using those cells available next April.
Those packs would become the replacement for any current Leaf batteries replaced under warranty for loss of capacity.
Nissan has not yet decided whether the new battery would be fitted to all new Leafs, executives told Green Car Reports.
Phoenix forum Saturday
Nissan executives first discussed the new battery at a Saturday night meeting in Phoenix with 10 Nissan Leaf owners.
The company will post a detailed announcement sometime today on the MyNissanLeaf forum.
Andy Palmer, the company's chief global marketing officer, joined communications staff Jeff Kuhlman and Brian Brockman, along with Billy Hayes, Nissan's vice president for global electric-car sales, at the Phoenix event.
Palmer, who works in Japan, is also a member of the Nissan board of directors. His presence at the event underscored the importance to Nissan of resolving this issue, Hayes said.
Lithium-ion battery pack of 2011 Nissan Leaf, showing cells assembled into modules
The group spoke to 10 local Nissan Leaf owners most affected by battery capacity loss from what Nissan terms "prolonged, extreme heat exposure."
In revealing the new cell project, the Nissan executives stressed that their plans depended on the successful completion of the testing now underway
While the company is "not quite ready yet" to launch the new battery, Hayes said, "we are really optimistic about the results" of the testing.
Test labs are now operating prototype batteries at sustained internal temperatures of 45 degrees Celsius (113 degrees Fahrenheit).
While pavement temperature in Arizona summers can reach as high as 60 deg C (140 deg F), the test temperature is far higher than that reached by batteries in more temperate markets like Seattle.
Thus far, Hayes said, the company has observed capacity degradation at the higher temperatures that's no different to that found in the bulk of Leaf batteries operated in more temperate climes.
Fewer than 1 in 1,000 affected
Hayes said Nissan has thus far replaced only 22 batteries for capacity loss in extremely hot climates--less than 0.1 percent of the 31,200 Leafs sold in the U.S. through July.
The executives told the Leaf owners that, assuming the new battery goes into production, Nissan will provide a coupon to every owner who has a pack replaced before next April.
2013 Nissan Leaf, Nashville area test drive, April 2013
That coupon, keyed to the car's VIN, and fully transferable, will entitle the owner to a further replacement pack based on the new chemistry if required, for a period of five years.
Hayes said the meeting also covered the recent software update to the Leaf's "state of health" gauge.
Following the update, some owners found their battery's health had "improved," he said, which wasn't the case. Instead, the reading was now more accurate than it had been under the old algorithm.
Sale of leased batteries likely
It was based on surveys not only of current owners but also of prospective Leaf buyers. Executives concluded that owners wanted a guarantee the battery would be replaced if necessary, but keyed to a specific battery state of health.
That program, Hayes revealed, is "still evolving"--and Nissan will "probably end up" selling batteries to customers after a specified time or mileage.
Down the road, that would avert the problem of the buyer owning a used Nissan Leaf--but not its battery, which under the current scheme, would belong to Nissan. (It would be transferable to any new owner of the Leaf, but owned by the company, not the buyer.)
For details on the battery-capacity warranty issue, starting in June, see this MyNissanLeaf thread.
It contains 33 screens of comments, but the most recent are from owners who attended the Phoenix gathering.