Nissan Bets on the Electric Car

DN Staff

June 24, 2010

11 Min Read
Nissan Bets on the Electric Car

Dan Hofstadter deliberated for weeks before recently plunkingdown $99 to reserve a NissanLeaf electric car. A Tucson-based consultant who specializes in engineeringanalysis, Hofstadter wanted to make sure everything about the Leaf - drivingrange, size, cost, reliability, emissions - would be right before making thedeposit.

"The environment is probably more important to me than it isto the average person," says Hofstadter. "But not to the extent where I'll buya car that inconveniences me."

Clearly, Hofstadter isn't alone. At the end of April, just afew days after Nissan began takingreservations, more than 6,600 people had lined up their deposits, despite thefact that the Leaf won't be available until December. For industry observers,the large number of reservations is a sign that the appeal of electric vehicles(EVs) is creeping outside the realm of committed, EV-at-any-costenvironmentalists, to people like Hofstadter. And that's the way Nissan wantsit.

"To buy this vehicle, there should be an economic rationale,"says Minoru Shinohara, senior vice president of Nissan's Technology DevelopmentDiv. "The customer has to believe it makes sense, compared to buying aconventional vehicle."

With the Leaf, Nissan believes it has reached that economicplateau. Since shelving the electric Altra almost a decade ago, it has kept itseye on the all-electric prize, working non-stop on EV batteries. The automakerhas pulled together big teams of engineers at its Technical Center and at itsAdvanced Technology Center in Atsugi, Japan, as well as at its Research Centerin Oppama and its Operations Center in Zama. Their task: to build ahigher-energy, lower-cost, EV battery.

Click here for a larger version

The Leaf's engineering team says theresulting battery will take the car 100 miles between charges, without cloggingup valuable space in the back seat or trunk. The key, they say, has been adedicated 17-year effort that has resulted in a two-fold boost in the battery'senergy density. By packing more energy into less volume, the battery providesNissan engineers with choices - longer range or smaller batteries, or anidealized combination of the two. That's why they've been able to store thebattery under the Leaf's floor while still reaching 100 miles of range.

"The breakthrough happened in 2002 or 2003," says Mark Perry,director of product planning for Nissan USA. "We changed the chemistry, went tolaminate cells, and at the end of the day, we had twice the energy density.That allowed us to optimize the vehicle platform. Suddenly, we had a massmarket vehicle concept."

Inglorious History

For automakers, the idea of a mass market electric vehiclehas been a technological Holy Grail since a string of EV failures a decade ago.Back then, Nissan's Altra EV died, along with the GM EV1, Chrysler EPICMinivan, Ford Ranger EV, Honda EV Plus, Toyota RAV4-EV and GM S-10 electricpickup. In the end, EV enthusiasts blamed a host of perceived troubles, butmanufacturers were in lockstep on one issue: They needed a better battery.

The EV battery lacked energy density,they said, just as it had for nearly 100 years. Legend has it that ThomasEdison and Henry Ford collaborated on the challenge of building a higher-energybattery a century ago. Given five years, they said, they could lick the batteryproblem. But while they developed a product, their battery's energy density wasjust a fraction of that of a gallon of gas, and the EV gradually disappeared.

When major automakers resumed the questin the 1990s, they tried a succession of technologies: zinc-air; lithium-sulfur,zinc-nickel oxide, sodium-sulfur, lead-acid, nickel-metal hydride, lithium-polymer,lithium-ion and others. Nickel-metal hydride and lithium-ion emerged as strongcandidates because of their higher energy density, but the cost was high.Meanwhile, the venerable lead-acid battery offered low cost, but its energydensity numbers were just too puny.

Worse, high-energy battery technologies - lithium-ion being acase in point - typically suffer from high costs. Cost estimates varydramatically (see sidebar), but even the most optimistic automakers agree thattoday's lithium-ion battery cells cost around $500/kW-hr. Add coolingstructures and battery management to that, and the entire pack comes to about$700/kW-hr, and that's an optimistic figure. Some experts contend the realfigure is closer to $900/kW-hr.

Given such costs, automakers face adilemma. Most believe there's a market, willing and anxious, for electric cars.But a big 40-kW-hr EV battery could cost $30,000 or more. All costs of theremaining vehicle must be placed atop that. At that point, the electric vehicleleaves the realm of the working man, who often can't afford a second car thatcosts $40,000 or more, and who doesn't want a primary car with a 100-milerange.

That's why some automakers, such as General Motors, aren'tmigrating to battery-electric vehicles for now. After famously shutting downthe EV1 program, GM's executives say they'll be very careful about pursuingpure electrics. "What we learned from the EV1 is that if you have a limitedamount of range and a less-than-predictable driving pattern, then you'll alwaysrun across the possibility of range anxiety," says Rob Peterson, a GMspokesman. "In general, people don't want to plan their lives around charging."

Lessons Learned

Against that backdrop, Nissan challenged the status quo bydeciding to re-enter the pure electric car market. The company's executives saythey can't point to a particular moment of decision, but the public learned ofit at the Los Angeles Auto Show in November 2008. There, Nissan CEO CarlosGhosn laid out his zero-emission vehicle vision in a way no one ever had. "InChina there are 50 cars for every thousand people; in the U.S. there are 800cars for every thousand people," he told reporters. "We will need anotherplanet if China catches up to the U.S."

Although Ghosn talked about zero-emission vehicles on thatNovember
day, Nissan engineers say the decision may have been reached as much as fouryears earlier. By that time, they'd had sufficient experience with their ownmonolithic lithium-ion EV battery and they knew the vital signs were trendingupward. Power was up two-fold. Energy was up
two-fold. Cost was declining.

"We had a huge number of engineers dedicated to the (battery)project," recalls Shinohara of Nissan. "It was the largest scale engineeringfocus we've ever had on a single technology, outside of engine design."

Most important, Nissan engineers had learned from their forayinto EVs with the Altra a few years earlier. There, they had employed thousandsof cylindrical, flashlight-sized 18650 lithium-ion batteries. The littlebatteries, each not much larger than a AA-sized cell, employed a costlycobalt-based electrode.

In the 2002-2003 time frame, Nissan engineers began workingwith another battery design. Instead of a small cylindrical battery, theyemployed a laminate structure for the cell. That raised their volumetricefficiency, largely because stackable flat cells use space more efficiently,whereas cylindrical cells have voids between them. Moreover, engineers changedthe battery chemistry, jettisoning the cobalt-based lithium-ion design andreplacing it with a so-called "manganese spinel," which uses a crystallinestructure that remains stable, even during charging. In addition to providinggreater energy density, Nissan engineers realized another benefit: Manganesewas far less costly than cobalt.

"Suddenly, we had a battery pack that washorizontal, instead of vertical," Perry says. "That way, you don't have to giveup rear-seat room or trunk space. We were able to stack these things likewafers, under the front seat and under the load floor."

The big breakthrough, though, was the energy density. Energydensity, which translates directly to driving range, had suddenly jumpedtwo-fold. Nissan still won't say what their energy density is, but expertsestimate it to be between 140-150 W-hr/kg, a gigantic leap beyond what was usedin earlier EVs.

"An energy density of 150 (W-hr/kg) is agreat number," says David Swan, founder of DHS Engineering,which specializes in battery-related research and development. "It's a numberwe would have given our front teeth for back in the a euro ~90s."

Beyond the Vehicle

How well Nissan has learned the lessonsof electric car design is evident from the company's choices for the Leaf. Someof the Leaf's technology is carried over from the Altra EV of a decade ago, butwith additions - sort of an "Altra-plus" approach.

The Leaf's drive motor is a perfectexample. It delivers a tad more pep than the Altra motor - about 107 hp (80 kW)for the Leaf, compared to 83 hp (62 kW) in the Altra. Speed is up, too. TheLeaf tops out at about 90 mph, compared to 75 mph for the old vehicle. At thesame time, however, Nissan engineers kept the technologies that worked. TheLeaf, like the Altra, uses ac synchronous motors (Nissan won't say, however,whether they still employ neodymium-iron-boron magnets).

Moreover, the battery control and motorcontrol are a direct result of earlier experience. Having learned from theAltra, Nissan engineers carefully programmed the battery management algorithmsto watch battery temperature, as well as charge and discharge. That way, theycould conserve energy and eke out as much range as is feasible. "We know all ofthis by experience," Shinohara says. "We learned, then we applied our knowledgeto manage the state of power and energy in the battery."

With the exception of microcontrollersand a few minor parts, virtually everything is done in-house. Motors andinverters are designed and built by Nissan. Battery modules are designedin-house, then shipped off to NEC Corp. formanufacturing.

The greatest lessonlearned, however, goes beyond the realm of component design. With the Altra,Nissan engineers found that consumers were concerned with recharge time. In theminds of many, recharge time trumped range as the EV's biggest drawback. Forgetthe 100-mile range, consumers said, they didn't want to drive to a distantlocation and then find they had an eight-hour wait before they could return. Todeal with the problem, Nissan executives began teaming with the U.S. Dept. ofEnergy (DOE), municipalities and private companies to begin the odyssey ofmaking recharging simpler. Working with the ElectricTransportation Engineering Corp. (eTec) and a whopping$100 million DOE grant, Nissan will deploy up to 1,000 battery electricvehicles in five states, which will install 12,500 220-V charging stations and250 more 440-V fast-charge stations.

The key to such efforts could be the 440-V stations, whichwould enable electric cars to go from near-depleted to 80 percent recharged in25 minutes. "You could drive 100 miles and have a sandwich while your vehicle rechargesin the parking lot," says Nissan spokesman Brian Brockman. "Then you could goanother 70 or 80 miles before you'd have to charge
it again."

At the same time, however, Nissan is also partnering with AeroVironment Inc.on the installation of home charging stationsfor the Leaf. The home charging stations, which combine charging algorithmswith intelligent thermal management, are capable of charging a Leaf in about eighthours on a 220-V line. Nissan is working with AeroVironment, not only toprovide the stations, but also to enable Leaf buyers to access a nationwidenetwork of licensed electricians to install the chargers in garages. Thecharging stations could be a key part of the marketing puzzle for Nissanbecause, without them, many buyers would be looking at a 16-hour recharge on a110-V power line.

"If customers want to do a one-stop shop, they can do it,"Perry says. "They can purchase the Leaf and have Nissan do the chargerinstallation anywhere in the country."

A New Beginning

By taking advantage of the growing nationwide infrastructureand the gradual improvements in battery technology, Nissan executives believethe Leaf may be in a position similar to that of the Prius of 10 years ago. TheLeaf, they say, is ready to grab a share of the global automotive market. Its480-lb battery pack is far smaller than the packs of a decade ago that filledtrunks and rear seats. It's less costly and still offers 100 miles of range. Atthe same time, the Leaf's electric powertrain provides better acceleration thanthose of gasoline-burning vehicles and is significantly quieter

Moreover, Nissan executives believe today's consumers have adifferent mindset than those of a decade ago. "The number of people who aretrying to live sustainably is growing and growing," Perry says. "They'reworried about the environment and they're worried about what they're leavingbehind for their children. You can see it in all the market research data."

The belief in EVs is also spreading to other corners of the autoindustry. Ford, Chrysler, Mitsubishi, BMW, Infiniti, BYD, Daimler, Tesla andothers have announced pure electrics.

Still, not everyone is on board. Toyota and GM believe theimmediate future lies in plug-in hybrids. Many auto industry analysts are unconvinced,as well, largely because they believe the battery issue is still unsolved. "Theenergy density is a lot better," says Donald Hillebrand, director of the Center for Transportation Research atArgonne National Lab. "But it still isn't good enoughto convince the bulk of consumers that they can rely on an electric vehicle."

"It might be a losing proposition," adds Donald R. Sadoway,professor of materials chemistry at MIT and nationally recognized batteryexpert. "But if it keeps the electric car alive in the minds of policy makers,then when we do find the right battery - which will be as good as lithium-ionbut at a more acceptable price - we'll be ready."

Although Nissan plans to build 50,000 of the vehiclesper year, the company's executives have acknowledged that electric car adoptionwill be slow, at least in the beginning. But they're prepared for the Leaf'spowertrain to play a back-up position to the internal combustion engine forsome time. "We're not saying that electric cars are our singular strategy as wemove forward," Perry says. "But in the end - 2030, 2040, 2050 - we'll reach apoint where the transportation sector has to switch over. We're all going tohave to do it."

Sign up for the Design News Daily newsletter.

You May Also Like