Tesla CEO Rips on Nissan's Battery Technology, Says It's "Primitive"

i would worry if you live in really hot /cold weather I think air cooled EV do better in 70 degree weather or get a themo gel cooled wrap on the battery and pay more money for it- like some ev's out there, yes volt is and tesla is too.

Further to my post above, here are a couple quotes that touch upon and reflect the more detailed explanation and scientific references I gave above …

GM-Volt.com: Achieving a ten year 150,000 mile goal is something it sounds like you’re very confident in now.

Bob Lutz: "Without committing to it being ten year or 150,000 warranty basically we are very very confident in the capability and the life of this battery in all but the hottest climates. So it could be that in certain very hot climates where people leave this thing in a baking supermarket parking lot all day, these lithium ion batteries, if they get much over 95 or 100 degrees Fahrenheit, they quickly start losing life. So we may have to adjust warrantees, but we really haven’t decided how to do that yet."

…

GM’s Volt executive Tony Posawatz explained why separate battery HVAC is so important in electric cars.

“Thermal management has bookend issues to manage: minimized power at low temperatures and life reduction at high exposure to higher temperatures,” he told Wired. “If you want to replace your battery every four to five years and someone is willing to pay for [a replacement battery], either the customer or the manufacturer, a modest or minimal HVAC system may work.”

Excerpted from:

http://gm-volt.com/2010/05/03/bob-lutz-on-chevy-volt-pricing/

and

http://gm-volt.com/2010/01/28/nissan-taking-shortcut-on-leaf-battery-no-...

You might also want to check out the following article:

www.wired.com/autopia/2010/01/nissan-leaf-2/

Responding again to Darell (following up on my previous two posts above) …

> When I said we won't know how long the batteries last,
> I didn't mean the chemistry - I meant the specific
> application in the Nissan Leaf. That we can't really learn
> by studying documents of battery performance.

Well, if it’s in-vehicle/on-road lithium battery life experience that you’re looking for, and Nissan’s specifically, you don’t have to wait 5 years to find that out. The 15-year on-road experience with Nissan’s lithium-powered EVs in Southern California has seen such high rates of capacity decay and degradation that their lithium battery packs have typically needed to be replaced every couple years. One would hope and presume that this latest iteration of Nissan’s LiMn2O4 batteries that are going into the Leaf is greatly improved over earlier versions, and I’m confident that that is indeed the case.

A good indication of how long the Leaf’s battery pack will last in a hot climate is what Nissan has been telling fleet managers in hot climates, and that is to expect a 4 to 5 year life. This is why fleet managers -- as well as many EV-savvy/knowledgeable individuals -- in hot climates are planning to take the Leaf on a 3-year lease, rather than purchase the car, and then return it to Nissan at the end of the 3-year lease. (It is for this same reason that I myself am planning to lease, rather than purchase, the Leaf.) In fact, Nissan is actively encouraging this -- for customers in hot climates to take the Leaf on a 3-year lease rather than purchase -- in order to relieve and take that battery degradation problem out of the customer’s hands and let Nissan assume that risk and deal with that problem.

Although you (and the public in general) may have some uncertainty in your own mind (because you don’t have any familiarity or experience with this issue) about the necessity of a robust, advanced, liquid-cooled active thermal management for the current generation of lithium-manganese (which, out of all the various lithium cathodic subchemistries, is the most heat sensitive and has the highest and fastest rate of capacity decay and degradation at higher ambients) batteries in order to achieve acceptable longevity in a hot climate, there is no doubt or uncertainty about the necessity of that among battery engineers in the battery and auto industries. To the contrary, there’s a strong consensus on that point, including even among Nissan’s own engineers, who argued for just such a liquid-cooled thermal management system but were overruled by senior management on grounds primarily of cost and secondarily because senior management and the marketing folks didn’t want to give up the third (middle) seat in the back, which would have had to have been given up and sacrificed for a taller battery pack assembly in order to accommodate the liquid-cooling TMS (as is the case in the Volt).

Carlos Ghosn has been refreshingly candid in admitting that the Leaf’s design decisions have been dictated by the bean-counters’ spreadsheets, as well as by the marketing folks, while relegating the engineers to the back seat (literally as well as figuratively). It’s been very much a case of accounting and marketing trumping engineering. Nissan has led with accounting and marketing on the Leaf, while GM has led with engineering on the Volt.

Nissan North America CEO Carlos Tavares has been similarly refreshing in his own candor in admitting that Nissan’s 8-year battery warranty decision was driven entirely by marketing considerations and public perception and was not based on engineering, in fact was completely divorced from engineering. GM’s announcement of their 8-year battery warranty for the Volt forced Nissan’s hand into matching that warranty several days later, due to competitive pressures, because Nissan simply could not afford to publicly capitulate to GM on this point and so openly expose their engineering weaknesses on the Leaf relative to the Volt.

In making the difficult (and painful) decision to match GM’s 8-year battery warranty, Nissan management understood and knew full well that this will result in them taking some losses 4-5 years down the road in having to replace battery packs under warranty in hot climates. For one thing, that’s why they’re encouraging people in hot climates to take the 3-year lease rather than purchasing the car. But more fundamentally, this whole thing was basically just a cold, hard-nosed, bottom-line, calculated business decision, pure and simple, … similar to other such types of business decisions that other companies in the automotive and other consumer products industries make all the time. This goes back to Darell’s “out-of-his-hat” speculative numbers, that I followed up and elaborated on in my first post above. Nissan management has calculated that, in the aggregate, it will cost them less to replace battery packs under warranty after 4-5 years in the 10% climate outlier tail (for those few hot-climate customers who don’t take the hint to go for the 3-year lease rather than purchase) than it would have cost them to design, engineer, and manufacture an advanced, robust, liquid-cooled thermal management system for each and every car for the entire country.

But lately Nissan senior management has begun to realize that they’re starting to suffer a public perception problem of the type that they had hoped to avoid (and be able to slide by, through the launch and first year or two, sweeping all of this under the rug and keeping it under wraps) but that has become unavoidable as all of this is starting to seep out into the public domain, getting revealed and exposed, with greater public discussion of this whole issue. Senior management is now starting to get worried about the possibility of a backlash and that their design and development decisions to let accounting and marketing trump engineering are going to come back to haunt them, just as Nissan’s engineers had warned would happen. So now we’re seeing Nissan senior management starting to backtrack on their previous party-line position (for public consumption) with respect to the whole thermal management system issue and are doing a reversal where they are now saying that they’re planning an advanced liquid-cooled TMS for the next model upgrade of the Leaf.

The problem with this, however, is that this will require a fairly substantial redesign and retooling of the vehicle platform, as they gave up that possibility when they committed to the current vehicle design of having sacrificed a robust thermal management system in favor of a third (middle) seat in the back. So it’s going to be back to the old drawing board for the next model version of the car.

… Which brings me, finally, to Tom’s question to me:

> Nice comments Charles. Do you think a liquid cooled, complex
> thermal management system could/should be offered as an
> option, albeit an expensive one?
> Kind of like how they offer cold weather packages to ICE
> cars now with engine block warmers, larger batteries, wiper
> defrosters, etc.
>
> I know it may only be necessary for 10% or so of the population,
> but that’s still a lot of potential EV owners.

I would echo Darell’s comments on that being a compelling idea that you raise there, Tom. In addition to what Darell said, I would just add, by way of example … take a look at the production plans for the Tesla Model S, wherein Tesla is planning to offer three battery pack options of different sizes and capacities, with 160, 230, and 300 mile ranges, respectively, for the same car. So yeah, I do think something like what you suggested could be done and find that an intriguing possibility.

I should say, however, looking out 5-10 years, towards 4th and 5th generation EVs [with the current generation of Roadster, Volt, and Leaf being 2nd generation EVs, (at least from the perspective of those of us who have been driving 1st generation EVs for a number of years now), and vehicle generation development cycles getting shorter, being compressed toward 3 years, instead of the traditional 4-5 years], that I don’t think sophisticated thermal management systems will ultimately be the solution to this problem. They are really just a short-term, somewhat kludgey (and very expensive) fix for the current (2nd) and next (3rd) generation vehicles, to get us through the next 5-6 years. We’re going to have real problems, in terms of the economic viability of EVs and their adoption and penetration rates, as intended mass-market vehicles, if we’re still using these expensive, complex, sophisticated, liquid-cooled, water-chilled thermal management systems (like that in the first generation of the Volt) to solve this hot climate battery life problem, as we get into the second half of this decade and approaching 2020. But I don’t expect that to be the case.

No, the ultimate answer to this problem is to be found in the electrochemistry, with an electrochemical solution, where the cathode, anode, and electrolyte are specifically designed, developed, and optimized for life and operation in a hot climate. Then the OEM doesn’t really have to worry so much about the thermal management system and can just go with a simple ambient forced-air type system that only runs during discharge and charge. For example, on the cathode side, carbon-coated nano-LiMnPO4 and carbon-coated nano-LiMn.8Fe.2PO4 both show excellent morphological and structural stability in solution at high temperature (60 degrees C) over time. (The specific mechanism of internal resistance increase at elevated temperatures, for current generation lithium battery chemistries, is primarily due to film growth on the particle surfaces, both at the cathode and at the anode, with the amount of such film growth being a function primarily of the level of heat exposure over time.) Such promising electrochemical solutions to the hot climate battery life problem have been well known and understood for several years now. It’s just a matter of scaling them up, working out licensing issues, and commercializing them. I expect to see such electrochemistry-based approaches and solutions employed in vehicles as we get into the second half of this decade, certainly as we approach 2020. We will definitely need them in order commercialize EVs for the mass market, if they are ever to become economically viable beyond the initial 5% early-adopter segment. I’m very hopeful and optimistic that that will indeed be the case.

I'm a Fan of the Nissan Leaf and others,I drive a 2010 Ford Fusion Hybrid.I have been looking @ the Leaf for purchase,After reading this forum and others about Thermal management issues with the Leaf and concerns,I now have to take a breath and maybe rethink ? I live in a Hot Climate along the Gulf Coast,the other day was 106 F. with heat index around 116 F. Summer months are hot ,humid etc.I would be one to purchase not lease a Vehicle of this nature,I have Concerns,but steel look forward to such vehicles !!

Thanks for all the Great Info. !

Good discussion!

A few other things to consider here are thermal mass, parallel strings, and temperature's effects on DC resistance.

The batteries are very massive. I work for Argonne and can vouch for the impact this has on Joule heating. Some of the lithium chemistries will see a 12-18C increase discharged at their full rate until empty with no cooling starting from say a 22C ambient temp.

Since EV batteries require significant capacity, they typically have multiple parallel strings which divides the current through each string accordingly further reducing joule heating.

Lastly many of these chemistries see a reduction in resistance as they warm up with again further reduces joule heating.

As far as ambient heating is concerned any of them will warm up to the ambient. There are some active cooling devices working on the same priciples as your AC system (and a few other methods) but they do add cost and typically consume more energy (reducing range). They also add mass (reducing acceleration and range).

My guess is Nissan would rather have most of the customers enjoy improved range and performance and honor the warranties in those select warmer areas as opposed to the trade off of adding the cooling systems.

Elon likely just doesn't know what he's talking about.

I support Tesla all the way, they have been in front of the curve since 2007 and continue to make amazing improvements.
My question is what happens to these batteries when they need to be replaced, are they recyclable or are we creating yet another toxic element that will sit in our landfills for the next 5000 years?