Nissan Re-Engineers Battery Pack for Leaf

Status
Not open for further replies.
Joined
Aug 30, 2004
Messages
35,302
Location
CA
Quote:
Nissan executives told a gathering of LEAF drivers in Phoenix on Saturday night that company engineers are currently testing a revised lithium-ion battery chemistry that appears to withstand extremes of heat far better than the cells found in existing LEAF battery packs.

As GreenCarReports explained, Nissan executives said the new packs are performing well at an internal sustained temperature of 45 degrees Celsius (113 degrees Fahrenheit) without showing any signs of heat-induced loss of capacity. Instead, the new cell chemistry demonstrates characteristics in line with existing LEAF battery packs found in cooler climates like Seattle.

Without an active liquid-cooled battery management system—as found in cars like the Tesla Model S, Chevrolet Volt, and BMW ActiveE—the lithium-ion battery pack in Nissan’s LEAF electric hatchback is vulnerable to heat. In places like Phoenix, that can lead to premature degradation of the battery pack, resulting in a loss of range completely unacceptable to owners. The issue has been a headache for Nissan customer-service headache and a public relations mess.

A revised battery chemistry being tested by Nissan could put an end to heat-induced premature battery aging—although the company is not talking about a liquid-cooled system that has essentially become standard in the industry.

As Soon As April

Nissan plans to start manufacturing battery packs with the modified cell chemistry by April next year, and will use the newly-built packs to replace existing LEAF battery packs replaced under its battery capacity loss warranty.

At Saturday’s meeting, executives from Nissan—including Nissan’s chief global marketing officer Andy Palmer, along with Billy Hayes, Nissan’s vice president for global electric car sales, as well as two communications executives—said that less than one tenth of a percent of LEAFs sold in the U.S. through July this year have suffered premature battery aging, and only 22 battery packs have been replaced under warranty for battery issues.

In a gesture of goodwill, executives said that should the new battery pack chemistry pass validation and enter production, the owners of those 22 cars will be sent a coupon, keyed to the car’s VIN and transferable between current and future owners of the car. If those 22 cars require a second battery pack within five years, Nissan says the coupon will entitle the owner to a further replacement battery pack, built using the more robust cells.

At the meeting, discussion also turned to Nissan’s replacement battery program. Frustrated that Nissan’s current plan to lease, rather than sell, replacement battery packs, owners peppered the executives with questions about its battery program.

Admitting that the program was “still evolving,” Hayes told the assembled crowd that at some point in the future, Nissan may end up selling replacement battery packs to customers after a pre-determined period, essentially allowing them to end the lease and buy the replacement battery pack outright after a set period of time or miles.


http://www.plugincars.com/nissan-testing-new-battery-pack-leaf-128088.html

As a reference, this was the issue that Nissan Leaf owners were experiencing in certain hot climates: LINK
 
Good news for early adopters of EVs for mainstream use.
Avoiding liquid cooling avoids cost, complexity and a failure point.
If the Leaf actually takes off in sales, aftermarket rebuilt or new battery packs will become available.
Identifying and replacing bad cells in Prius battery packs has become commonplace.
 
Originally Posted By: fdcg27

Identifying and replacing bad cells in Prius battery packs has become commonplace.


This is OT but - individual cell replacement must be done carefully, as the packs need to be rebalanced afterwards. The last that I heard, Luscious Garage is loading the Gen 2 Prius battery packs with cells from Gen 3 vehicles: https://www.facebook.com/photo.php?fbid=...e=1&theater

The savings are not that significant anyway, so to me, I'd rather just buy a new battery pack when the time comes.
 
Really?
I know of a couple of indies who are indentifying and replacing bad cells in Prius packs for reasonable amounts of money with good results.
How much is a new pack for a Prius?
The packs do seem to live long lives, since the Prius system keeps them within a very narrow range of potential.
 
Originally Posted By: fdcg27
Really?
I know of a couple of indies who are indentifying and replacing bad cells in Prius packs for reasonable amounts of money with good results.
How much is a new pack for a Prius?
The packs do seem to live long lives, since the Prius system keeps them within a very narrow range of potential.


IIRC the new packs for the Prius around just over $2500. Used or rebuilt ones are in the $1500-$2000 range. The difference is not too significant for the peace-of-mind that a new one gives you.
 
Originally Posted By: The Critic
The difference is not too significant for the peace-of-mind that a new one gives you.


Yes, but you can rebuild it yourself for $50 (assuming one cell is bad).
 
Originally Posted By: The Critic

As a reference, this was the issue that Nissan Leaf owners were experiencing in certain hot climates: LINK


Thanks for posting this. What a mess. Nissan clearly didn't test the car properly in hot climate.
Makes me think harder about any future cars with lithium batteries.
Any issues in Volt?

Edit: Not good.

Quote:
One disappointment is that the Volt and other Lithium-ion battery-powered electric vehicles may not be viable in hotter climates, such as some states in the American Southwest. Despite the fact that Volts will be sold in these states, performance may be significantly undermined due to the heat. Volt Chief Engineer Andrew Farah describes, "The Volt may not be right for everyone. If you live in the Southwest, depending on how you use your car, the Volt might not be right for you."


http://www.dailytech.com/Chevy+Volt+Cant...rticle16969.htm
 
Last edited:
Because of very bad things that can occur due to impedance mismatch and overdriving cells, individuals should never be replaced, especially in LI-ion packs.

I'd bet that Nissan went to an LTO anode for stability.
 
Originally Posted By: Tegger
Originally Posted By: friendly_jacek
Quote:
"If you live in the Southwest, depending on how you use your car, the Volt might not be right for you."

http://www.dailytech.com/Chevy+Volt+Cant...rticle16969.htm

That's really amusing, considering that California's CARB mandates are a prime reason for the existence of the Volt in the first place.


When I lived in CA the weather was always a lot nicer than here in the midwest. Here we face back-to-back 100+ degree days, back in CA it was typically 60-70ish in the summer, occasionally 80.
 
Originally Posted By: SteveSRT8
I am amazed that a real engineer on the GM payroll said that! Astonishing.

He can get in big trouble...


If so he's long fired, that Volt article is from 2009, discussing the 2011 models...
 
Status
Not open for further replies.
Back
Top Bottom