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Updated Nissan LEAF available in Japan; range improved by 14%; new motor uses 40% less dysprosium

20 November 2012

Nissanmotor
Nissan’s grain boundary diffusion process allows it to reduce the use of dysprosium in the traction motor in the updated LEAF by 40%. Click to enlarge.

Nissan Motor Co., Ltd. released the updated Nissan LEAF electric vehicle (EV) in Japan. The battery-electric LEAF, now in its second iteration, is now available at Nissan dealers nationwide. With the updates, range at full charge on the JC08 cycle is expected to be 228 km (141 miles)—a 14% improvement over the original version of the LEAF with a 200-km range (124 miles) on the JC08 cycle.

Among the enhancements to the updated LEAF is a newly developed electric motor that will reduce the use of the rare earth element (REE) dysprosium (Dy) by 40% compared to conventional EV motors. The new synchronous AC motor offers the same power output (80 kW) as its predecessor, but less torque: 254 N·m for the new motor, vs. 280 N·m for its predecessor.

In addition to the LEAF, Nissan plans to use the lower dysprosium motor in future hybrid electric vehicles (HEVs).

Using a neodymium-based (NdFeB) magnet, motors used in electric vehicles need to be compact in size with high performance. Dysprosium is added to neodymium magnet’s to strengthen heat resistance. In conventional electric motors, dysprosium is uniformly added to the neodymium magnet, but the new motor—developed in a joint effort with Nissan’s suppliers—features a breakthrough grain boundary diffusion process.

Instead of uniformly adding the dysprosium to the magnets, the new process distributes dysprosium around each crystal grain’s boundary, which improves the magnet’s heat resistance while maintaining high performance levels. The result of this process is a 40% reduction in dysprosium use while still keeping heat-resistance levels comparable with conventional electric motors.

Nissan says this new electric motor is only the first step in the process to limit the use of rare earth elements. The company plans to adopt the grain boundary diffusion process for its hybrid motors, with the goal to ultimately achieve zero usage of dysprosium in other components as well.

With all its the enhancements, the updated LEAF has reduced its power consumption: 114 Wh/km on the JC08 vs. 120 Wh/km earlier. (Battery pack capacity remains the same: 24 kWh.) Other enhancements to the basic LEAF powertrain include:

  • The high voltage power electronics (inverter and DC/DC converter) and electric motor were integrated, resulting in a 30% volume reduction and a 10% mass reduction.

  • Weight is reduced by about 80 kg (176 lbs) compared to previous model. This was achieved via the combined powertrain unit, integrated functions, streamlined battery module and case structure, and use of lighter parts.

Driving performance is enhanced by improved steering response in the medium-speed range and optimized suspension characteristics associated with weight reduction. In addition, changes to the regenerative brake control system enable more efficient power generation when the brakes are operated.

Auxiliaries also have reduced power consumption with a heat-pump cabin heater, heated seat for all seats, heated steering wheel and heat shield ceiling.

A long-life charging mode—in which the battery is charged to 80% to extend the battery life—is now available in any charging mode.

The navigation system also provides a “Stop-off charging spot guidance” function, “Power-saving route guidance” function and “Battery capacity at a destination forecast” function which can allay potential range anxiety New ways to search for and locate charging spots easily and quickly. There is also a “Charging spot availability information provision” function, “Quick charger location display” function and “Unavailable charging spot display” function.

At present, there are approximately 400 sales outlets in Japan that are equipped with quick chargers. In order to offer even better convenience and accessibility for LEAF owners, Nissan plans to expand the availability of quick chargers to 700 sales outlets in Japan. When the expansion is completed, one-third of dealers will be able to offer quick charging service.

Since its debut in December 2010, Nissan has sold more than 43,000 units of the LEAF worldwide.

November 20, 2012 in Electric (Battery), Motors | Permalink | Comments (27) | TrackBack (0)

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That might come out to around 83 miles range on the EPA cycle.
It also helps a bit in concerns about battery life, as for a given number of miles the battery would cycle less often, and in addition even after those miles more range would remain, so that more use should be got out of the battery before it hasn't got enough range to be practical.

Putting the numbers together, according to Palmer Nissan rated the old Leaf at 60,000 miles on the lenient LA4 cycle to 80% capacity, on average.
That comes to only 45,000 miles or so on the EPA to 80% of the nominal 73 mile range, and if you charge to the recommended 80% level to get a longer life then after that 45,000 miles you would only normally get about 73*0.8*0.8 miles of range after that = 46.7 miles

For the new car you might get around 45,000/0.8 miles to the same level of battery capacity depletion, or around 56,250 miles.

After that you would have remaining 83*0.8*0.8 miles of normal range, or 53 miles.

Since the depletion curve flattens, it would then be quite a few miles down to the 46.7 miles of normal capacity of the old battery.

In my view the battery capacity would need to be increased to something like 30kwh to give an acceptable level of battery capacity loss and remaining available range after a few years, and even then it would be far worse than in other available chemistries, but it would at any rate start making financial sense.

Hmm, my maths is in error in the above.
The range for the new battery down to 80% capacity should be 45,000 times 1.14, the increment in the battery capacity of the new one, or 51,300 miles, not the 56,250 I gave.

The figures in the article are odd.
The range shows a 14% improvement on the JC08, up from 200km to 228km, whilst the figures for Wh/km are given as down from 120Wk/km to 114Wh/km, only a 9.5% drop on the same battery size.
One or the other is wrong.

It looks like the 114Wh/km is in error, as 24000Wh divided by 200km is 120Wh/km, whereas 24000Wh divided by 228 is 105Wh/km, not 114Wh/km.

Both figures are funny anyway, as you don't run the 24kwh battery until it is dead flat.

Davemart, the capacity loss issues are limited to hot places such as Phoenix (4.3 years to 70% capacity) and Texas.. but everything is ok in the NE and NW, there you will easily reach 10 years.

Herm:
No they are not.
The figures I gave are from Andy Palmer, and refer to the Leaf in more temperate climates:
http://green.autoblog.com/2012/10/10/nissan-andy-palmer-leaf-battery-degradation-crisis-video/

At the start of the video.
Those jolly japesters at Nissan in the same video put the average milage for Phoenix for 5 years down to 80% capacity at 7,500pa, or 37,500 miles.

That assumes that you have an air conditioned garage, or all bets are off, as the guarantee specifies that the battery is not kept for prolonged periods in high temperatures:
http://www.nissanusa.com/content/dam/nissan/pdf/techpubs/leaf/2011/2011-leaf-owner-manual.pdf

In the same remarkable interview he also reveals that Nissan has no plans in place, let alone costs, for replacement batteries.

So when the first battery looses too much range, as things stand you either buy it by the module at around $19k, or scrap or sell (!!) the car without a usable range left in the battery.

Battery performance and pack capacity have to be improved by 3X to 5X for extended range BEVs. That will take another 5+ years to come around.

Meanwhile, for a few extra dollars, there are a few very good HEVs on the market for those who really want to reduce fuel consumption by more than 50%.

For those with more $$$, there are a few more acceptable PHEVs to further reduce fuel consumption.

Their total level of engineering seems to be a bit behind that of Toyota, but hopefully, like Toyota, they will improve with each iteration.

So, 73 mile range down to 80% is 58 miles still. If I have a 30 mile commute, even at 80% I still have a usable car. However, if my typical drive is 30 miles, I would hardly ever cycle the battery below 50% and would therefore expect less battery degradation. Sure, we don't want consumers learning that there are ways for them to maximize their value in products, and that small changes to their habits don't necessarily mean a decreased living style (if you really think about what's important). We want them to consume to their maximum capability, always having some debt thus forcing them into jobs that will never get them ahead but allow there owners (excuse me, I mean employers) to get wealthy. I really fear that they would take a car like the leaf and continue to run it until it only had about 30 miles range, and thus not consume like we would prefer them to. I fear too, the after market and do-it-yourselfers that would take a used leaf and modify or upgrade it. How will we ever get rich on EVs? It's going to be difficult. We better stick to gasoline cars. That way we get the side benefit of having the need for a military industrial complex, that is very profitable, to police the oil fields of the world. Both the military industries and oil are very profitable. An added benefit is that as the price of oil goes up, profits go up on oil and the need for the military goes up. So, invest in oil and bombs, it's the best return on your money.

This seems to say that there is no battery capacity improvement(Battery pack capacity remains the same: 24 kWh.), but engine torque reduction (torque: 254 N·m for the new motor, vs. 280 N·m for its predecessor[-9%]) and weight reduction(176 lbs[-5%]) yielded 14% better range.

40% less dysprosium should mean lower cost.

Engineers could proofread too..

Brotherkenny:
I'm not quite sure what most of that has to do with the article.
Leaving aside the socio-political musings, or perhaps lifestyle instructions, the issue is how much the car costs and whether depreciation will hit too hard.
To be comfortable although the average distance travelled per day may be only 33 miles, you clearly need a margin over this.
How much is more debatable, but I would suggest that many may be looking for around double that to allow for longer runs, cold weather reducing range, etc.
So something like 66 miles may be a reasonable target for an electric vehicle, with some cars such as the Smart EV which are clearly very much town run arounds perhaps being able to get a bit less.
The Nissan using the present battery pack looses too much of its range after too few miles, so the cost per mile is way too high.

Why anyone would buy one, instead of perhaps lease, escapes me, even if they happen to go along with your metaphysics, as they can buy a perfectly good Energi which is unlikely to suffer from the same defect, and which would still do many of its miles on electricity, or indeed by the Volt.

"Those jolly japesters at Nissan in the same video put the average milage for Phoenix for 5 years down to 80% capacity at 7,500pa, or 37,500 miles."

7,500 miles a year is some artifact of Nissan's data collection system (or perhaps a bunch of retired codgers have purchased Leafs), the US average is 12,500 miles a year and simulations show 30% degradation in less than 5 years in Phoenix.. probably over 10 years in temperate climates such as England. 30% degradation means the battery is trashed by common industry guidelines, but if you only drive a few miles a day then it will be perfectly fine.

Eventually Nissan will have to let us know how much a 100% reconditioned battery will cost, right now they are too scared of the backlash if they tell us.

It may be way off, but couldn't a fan bring down heat extremes? If necessary, duct some AC, trading 10% of the 14% range gain for battery longevity?

Maybe Nissan isn't telling us how much a replacement battery will cost because their crystal ball is broken. I would not expect them to replace the current battery (say, in 5-8 years) with an old battery chemistry. I would expect them to fashion replacement batteries with state-of-the-art battery chemistries. If the CalBattery claims of "triple capacity while lowering battery cost up to 70%", commercially available in three years, are anywhere close to true, then Leafs with replacement batteries will be substantially improved cars. Batteries will be more energy dense and cheaper in five years; we just don't know by how much.

From 1st hand account of owners (and ex owners): apparently the average mileage for Phoenix for one and one half years is down to 80% capacity.

Similarly 2010 Civic in Warner Robins Georgia is on its second battery pack (now out of warranty) - as the battery deteriorates the mileage resembles the non-hybrid version.

Maybe the geometry as much as the airflow, is the problem - maybe the CONDUCTION to the surface of the pack (or lack of internal air passages), more so than the airflow available, is at fault.

ChrisL:

There are two issues here.

The first is that if anyone did buy the Leaf instead of leasing it, which seems a pretty daft thing to do now that the facts are in, then without an assured plan or price for a battery replacement then depreciation will by horrific right up until the point that the true costs are known.
Effectively almost all of the value of the car will disappear over 5 years, as selling a Leaf with maybe 80% only of its battery capacity left doesn't bear thinking about.

The second issue is that the only reason electric cars appear in any way reasonable in cost is due to the $7,500 subsidy.

This is not available on replacement batteries and that seems to me to be the likely reason that Nissan has not even made any plans to offer one.

So at present prices batteries may cost around $500 kwh, and the Nissan pack perhaps $12,000.

That is not a reasonable repair cost to pay on a 5 year old car, and even the most generous assumptions on falling battery prices make dubious sense when other chemistries should comfortably last as long as the car.

In my view Nissan have chosen the wrong chemistry, particularly in view of their not putting in liquid cooling, and competitors like the Chevy Spark simply will not have this problem.

A few positives: less weight of about 175 lbs, consolidation of units and more efficient units, a new battery chemistry from Hitachi (LiFePo, I believe) with better temperature specs...all translates to Nissan trying to reduce the cost of the car and at the same time increasing the range. When I bought my car, #669, I figured that this would be the case, i.e., that Nissan would continue to make improvements in each generation of the car.

I am disappointed at the progress of their battery technology because I fear it is still too expensive and their attempts to increase the car's range have been pretty weak. It seems to me they need to improve the range to an honest 100 miles at freeway speeds of 65 mph; never mind the fancy EPA specs, they mean nothing unless they can meet this practical requirement. That means a more energy dense battery; I don't see it yet and until they listen to the early adopters and can do this, they will not meet the expectations of most U.S. drivers.

'a new battery chemistry from Hitachi (LiFePo, I believe)'

Huh? I was aware that Hitachi were now a second tier supplier, but had they gone to LiFePo then presumably they would make a big deal of it, as the cycle life is radically better than manganese spinel, and would if not solve at least greatly reduce durability issues.

Still manganese spinel AFAIK.

What remarkable nonsense just to drive an over priced electric vehicle. The consumer is now put into the position to worry about a stable supply of dysprosium, lithium, vehicle range, and battery life. Who needs it? It's going from the frying pan into the fire. When the enabling technology finally arrives call me, in the meantime go back to the lab.

@Mannstein:
Absolutely!
Its a great thing that oil dependence causes no problems, does not cause wars and will exist in abundance forever from its abiotic supplies!

"It seems to me they need to improve the range to an honest 100 miles at freeway speeds of 65 mph; never mind the fancy EPA specs, they mean nothing unless they can meet this practical requirement."

"..and until they listen to the early adopters and can do this, they will not meet the expectations of most U.S. drivers."

Makes a lot of sense, esp. with US distances.

Another 20% range improvement could meet this minimum.

With web sites announcing multi-factor battery improvements weekly for years/decades - no problem.

Since gas prices have often doubled in weeks - repeated gas prices doubling during 5 or 10 years of future vehicle ownership seems likely.

Also, electric hardware costs fall over the years and a one moving part power train is cheaper to maintain then a thousand ICE moving parts.

For the next 10-15 years you would have to be rather daft to BUY an eletric car instead of lease one.

Pay for batteries or fuel.

Yup but still for now its FAR smarter to lease the car and thus its battery then it is to own it. Specialy concidering some of these companies are going to go belly up.

The replacement cost for the batteries will be included in the lease payments, so you pay for that anyway. It is the residual value that matters, I would not say Nissan is likely to go "belly up".

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