Gregoire's CleanTech Blog

EDF se branche sur le programme de voitures hybrides de Toyota

Le groupe énergétique s'allie au puissant japonais pour tester quatre prototypes de Prius rechargeables sur une simple prise de courant. Mais la commercialisation d'un tel modèle n'est pas encore en vue.

Faute de pouvoir préciser ses plans et son calendrier pour la livraison de sa Prius hybride de troisième génération, dont le développement de la batterie prend du temps, Toyota occupe le terrain avec « l'hybride rechargeable ». Le nouveau numéro un mondial de l'automobile a conclu hier un accord avec EDF pour tester durant deux ans quelques Prius « plug in », c'est-à-dire rechargeables sur une prise électrique, afin de lui donner un petit surcroît de puissance électrique sur de courtes distances. De même, Toyota va tester quelques prototypes identiques aux Etats-Unis, via des universités locales, et au Japon. L'expérience d'EDF en France sera limitée à quatre véhicules, « et pourra être étendue à l'avenir à d'autres pays européens ». L'énergéticien français poursuivra en parallèle ses essais en cours sur une flotte de huit véhicules Cleanova, des engins tout électriques ceux-là, promus par le groupe Dassault, animés par une batterie lithium-ion, « qui n'ont pas encore atteint un degré de maturité suffisant », selon EDF.

A travers cette nouvelle expérience, qui rappelle le programme Volt que GM espère commercialiser en 2010, Toyota cherche surtout à mesurer les caractéristiques de roulage de ce véhicule et affiner ses capacités techniques, avant de décider une éventuelle vente dans le grand public.
Des bornes « intelligentes »

« Nous voulons réunir des données pour promouvoir ensuite l'usage de l'électricité. Mais ce n'est qu'à l'issue des tests que nous pourrons déterminer la date d'une éventuelle commercialisation », souligne Masatami Takimoto, vice-président exécutif de Toyota Motor. Concrètement, la nouvelle Prius rechargeable pourra utiliser soit une prise électrique domestique, soit une des 200 bornes de recharge situées sur la voie publique en France (la moitié à Paris), à la suite de précédentes expériences qui se sont révélées des échecs.

Une nouvelle génération de bornes dites « intelligentes » est à l'étude. La voiture bénéficiera d'une dizaine de kilomètres d'autonomie avec cette charge, avant de passer au mode hybride classique, qui associe un moteur électrique et un moteur à essence traditionnel de 1,5 l de cylindrée. En mode électrique, sa vitesse se limite à 100 km/h, mais le temps de charge ne dépasserait pas une heure et demie.

Source : Les Echos

Novel Batteries Get a Boost

General Motors has announced it will work directly with A123 Systems, a start-up based in Watertown, MA, to develop batteries that are fine-tuned for the Chevrolet Volt, an electric vehicle scheduled for production in 2010 or 2011. The new agreement between the companies is designed to speed the vehicle to market.

The co-development deal is the latest in a series of announcements by the automaker indicating it is moving forward with plans for the Volt, an extremely fuel efficient hybrid. The Volt, first announced in January, will use batteries that can be recharged from a standard electrical outlet and is expected to get 40 miles on a single charge, eliminating trips to the gas station for average daily driving. While GM has not ruled out using batteries from another supplier, the agreement is a vote of confidence that A123's technology can meet the requirements for the vehicle, says Denise Gray, GM's director of hybrid energy storage devices.

A123 uses a new lithium-ion chemistry that allows its batteries to be much lighter and more compact than the nickel metal hydride batteries in existing hybrids today, and safer than the conventional lithium ion batteries found in consumer electronics. In June GM announced that it is working with the South Korean company LG Chem, and its subsidiary Compact Power, based in Troy, MI, to make both battery packs and the individual cells inside them. They also signed an agreement with an LG Chem competitor, the Frankfurt, Germany-based Continental Automotive Systems, to develop battery packs. Continental had planned to use A123 as a subcontractor to supply the batteries for these packs. The new agreement puts A123 in direct contact with GM on the Volt project.

At the end of 2005, A123 announced its first product, a cylindrical battery for power tools. For the Volt, A123 is shifting to a much bigger and flat, rather than cylindrical, battery cell that takes up significantly less space. Hundreds of these would be combined in a large pack, with control electronics and a cooling system, to power the Volt.

A123 employees have begun testing the new cell. In one test, a prototype cell, a silvery slab about the size of three decks of cards placed side by side, was crushed from the side to demonstrate its abuse tolerance. Unlike conventional lithium-ion batteries, which use a cobalt-oxide material that can overheat and cause laptops and cell phones to burst into flame, A123's batteries use a much more stable, and potentially cheaper, iron phosphate material. The crushed test battery showed no signs of overheating.

Earlier this year GM had picked A123 Systems as a potential supplier of lithium-ion batteries for a new version of its Saturn Vue hybrid that can be recharged by plugging it in, giving it a 10 mile all-electric range. It could be on the roads as early as 2009.

But the battery requirements for the Volt are much more challenging, requiring the different cell design. Whereas in the Vue power from the battery will be supplemented with power from a gasoline engine, the Volt will rely on batteries full-time. For the first 40 miles of driving, the battery will deliver power from being plugged in overnight. After that, the battery will continue to power the vehicle as it is recharged by an on-board gasoline-powered generator.

The new batteries must pack more energy into a smaller space, the reason for the flat design. But they also need to be fine-tuned for the power demands of the Volt. To do this, engineers can subtly alter the electrode chemistry, thickness, the type of electrolyte, and other aspects of the battery cell design. The collaboration with GM will give A123 direct access to more lab space and testing equipment that could allow A123 to more quickly sort through many subtle variations on the cell design, says David Vieau, A123's CEO. "You never get enough test capacity for all of the different variations you'd like to be able to consider," says Vieau. "We hope this [agreement] will accelerate the process."

Gray says GM hopes to have the batteries in packs within the next couple of months and to have these packs in a generic vehicle platform for testing by the end of the year. The technology could be in a prototype Volt sometime next spring, she says. GM's goal of a production model by 2010 or 2011, Gray says, is an "aggressive target." But the tests they've done so far since announcing the project in January have been encouraging. "We've got no information back that says uh-oh we can't do this," Gray says.

The Volt is going to be about the size of a Chevrolet Cobalt, which currently costs between $14,000 and $20,000 depending on the configuration. Rob Peterson, a GM spokesperson, says GM won't "price themselves out of that class" of vehicles with the Volt. He adds that if GM intended the vehicle to have a hefty premium, it would have made the vehicle a Cadillac. "It was a conscious decision to make it a Chevy," he says.

The agreement with GM does not mean that A123 will be locked out of doing work with other automakers. The specific cell the two companies develop together will be co-owned--so both companies will have to negotiate for how it might be used, Gray says. That could include putting the pack in cars by other companies, Gray says, since "it's in everyone's interest to achieve economies of scale to drive down battery prices." A123 still retains control over its novel battery chemistry, however. Indeed A123 has had discussions with other automakers and its batteries are set to be used in hybrid buses starting in 2008.

General Motors unveils new hydrogen-fuel-cell-powered chevrolet

Last week General Motors (GM) unveiled a hydrogen-fuel-cell-powered version of its Chevrolet Volt concept, a family of electric cars that get a portion of their energy from being plugged into the electrical grid. The first version, announced in January, married plug-in electric drive to a gasoline or ethanol generator that can recharge the battery.

But swapping out the generator for a fuel cell may be a step backward. That is in part because producing the hydrogen needed to power the fuel-cell version could increase rather than decrease energy demand, and it may not make sense economically.

"The possibility that this vehicle would be built successfully as a commercial vehicle seems to me rather unlikely," says Joseph Romm, who managed energy-efficiency programs at the Department of Energy during the Clinton administration. "If you're going to the trouble of building a plug-in and therefore have an electric drive train and a battery capable of storing a charge, then you could have a cheap gasoline engine along with you, or an expensive fuel cell." Consumers will likely opt for the cheaper version, Romm notes.

Still, the Volt is part of a promising trend toward automotive electrification--which could decrease petroleum use and reduce carbon emissions. It is part of GM's response to an anticipated future in which both petroleum and carbon-dioxide emissions will carry a heavy price, driving consumers to buy vehicles that run on alternative, low-carbon power sources.

The new Volt, announced in Shanghai, replaces the generator with a fuel cell and cuts the battery pack in half, in part to make room for storing hydrogen. The lithium-ion battery pack can be recharged by plugging it in. The fuel cell kicks in immediately when the car is started and provides power at a constant rate at which it is most efficient. If more power is needed, such as for acceleration or high speeds, the battery provides a boost of power, much like what happens in today's gas-electric hybrid vehicles. When less power is needed, such as when the vehicle is stopped or at low speeds, the battery stores energy to be used later.

By allowing the fuel cell to run at a constant rate, the batteries improve efficiency, cutting down on hydrogen consumption. The battery further improves efficiency by storing energy generated during braking. Compared with earlier prototypes, the new concept also uses a more advanced fuel-cell design (thinner stainless-steel parts were substituted for thick composite parts) and the vehicle is lighter, making it possible to have a 300-mile range using half the hydrogen.

The car emits no harmful emissions from the tailpipe. But because hydrogen fuel today is primarily made from fossil fuels this means the carbon-dioxide emissions are simply happening someplace else, Romm notes. He says that using renewable energy to charge up the battery in the gas-generator version of the Volt makes more sense than using it to make hydrogen. That's because it's more efficient to charge a battery than to make hydrogen, compress it, and then convert it back into electricity using a fuel cell.

Nick Zielinski, the chief engineer at GM responsible for advanced vehicle concepts, says that GM released the fuel-cell version in China because hydrogen has a better chance of taking hold there. In China, energy infrastructure is still being developed, and gasoline and electricity may not be available everywhere. "They could develop a hydrogen infrastructure much sooner than we do here. And a fuel-cell vehicle may make more sense than a plug-in-to-grid option because hydrogen may be much more accessible," Zielinski says. He adds that "hydrogen, when it's generated in a renewable way, produces no emissions. And that's where I think we'd like to get to."

With the Volt, the power source can vary according to the proposed market. In the original version revealed in January, likely to attract customers in the United States, the first 40 miles of driving are powered by energy stored in a battery pack that can be recharged by plugging it in. (See "GM's New Electric Vehicle.") That's enough range for a typical daily commute. For longer trips, a gas- or ethanol-powered generator recharges the battery, allowing for an additional 600 miles of range. In Europe, diesel generators can be used, rather than gasoline generators or fuel cells.

Other major automakers are also developing plug-in fuel-cell and battery-powered vehicles. In January, Ford unveiled a vehicle that runs off stored power in the battery for the first 25 miles before a fuel cell starts recharging the battery, which can add an additional 200 miles of range. As with GM's Volt, the fuel cell could be replaced by a gas or diesel generator.

Both the fuel-cell and generator versions of the Volt will face challenges, but it's likely that the fossil-fuel versions will reduce carbon-dioxide emissions more than the fuel-cell versions. The Volt equipped with a gas-powered generator has a large battery pack that will allow most drivers to skip the gas station altogether for daily commuting. And because the generator is very efficient, even for trips longer than 40 miles it may use less gas than ordinary cars. Of course, total carbon emissions will depend on the source of the electricity for charging the battery, but the relatively high efficiency of power plants compared with conventional vehicles will likely lead to lower carbon-dioxide emissions overall.

The main challenge with this vehicle is that a big enough lithium-ion battery pack, made to withstand the abuse of automotive applications, hasn't yet been created. Zelinski says that no more major breakthroughs in battery-cell technology are needed. All that's left is to integrate hundreds of these cells to make a big battery pack. That's going to be challenging, but, he says, "it's something that can be handled in a straightforward, solid-engineering way."

Plug-In Hybrids car : when A123 Systems' CEO makes his show with G. Bush

Plug-in hybrid vehicles, which can be recharged using a standard wall outlet, are becoming increasingly practical because of advances in battery technology. And now the technology is also gaining support in Washington, with the promise that it could soon receive the type of federal tax incentives that have helped fuel the sales of conventional hybrid vehicles over the past several years.

Like conventional hybrid vehicles, plug-in hybrids can run on gasoline and electricity. But plug-in hybrids have bigger battery packs that can be easily recharged. As a result, they can run longer on electric power, saving much more gas than an ordinary hybrid can. Depending on the configuration of the vehicle, people who drive less than 40 miles a day could use no gasoline at all, while the average U.S. driver could see fuel economy of 150 miles per gallon. Although the vehicles consume electricity, the power will come at a fraction of the cost of gasoline, and it promises to reduce greenhouse-gas emissions.

Although no major automaker currently sells a plug-in hybrid, a handful of companies provide aftermarket conversion kits. Indeed, at the White House last Friday, President Bush viewed one example of a Toyota Prius, a conventional hybrid car, that had been converted into a plug-in hybrid using a battery pack that fits in the car's spare-tire compartment.

President Bush called the plug-in hybrid and an all-electric-powered pickup "living proof" that his ambitious goal of reducing gasoline consumption by 20 percent in 10 years is possible. He also renewed his request for research money for alternative energies. The administration's proposed fiscal-year 2008 budget, which was released February 5, includes $41.8 million for battery- and energy-storage research and development.

Interest in plug-in cars extends to Congress. In January, a bill was proposed in the Senate that would provide an up to $4,200 tax credit to offset the expense of plug-in hybrids, which can cost about $10,000 more than a conventional hybrid.

At the White House event, David Vieau, CEO of A123 Systems, a startup based in Watertown, MA, whose batteries are used in the plug-in hybrid, proposed to President Bush that the government offer $2 to $3 billion in tax incentives over the next seven years and provide $300 to $400 million in research dollars over the next few years. Such incentives, Vieau said, could help plug-in hybrid conversions grow from a few hundred now to thousands later, starting in as soon as 12 months.

Deron Lovaas, who heads the vehicle campaign at the National Resources Defense Council, says that several such tax-incentive bills will likely be submitted this year. "There are sure to be others, because there's a lot of enthusiasm about this in D.C. right now," he says.

Lovaas says that tax credits could have a significant impact on plug-in hybrid sales. He cites the success of tax credits for conventional hybrids, whose sales have doubled every year since 2001. (See a summary of current tax credits here.)

Automakers have recently expressed increased interest in developing plug-in hybrids. Late last year, General Motors (GM) announced an upcoming plug-in version of its Saturn Vue. (See "GM's Plug-In Hybrid.") A123 Systems announced an agreement with GM to help develop a prototype battery pack for the Vue. The packs are scheduled to be ready for testing in vehicles by the end of the year. In January, GM also revealed its Volt concept car. The vehicle takes plug-in hybrids a step further by using an all-electric drive train. The battery pack can be recharged by an onboard gas-powered generator or by plugging it into the wall. (See "Powering GM's Electric Vehicles.")

A study released last week suggests that over time, plug-in hybrids could cut overall vehicle emissions of carbon dioxide in half, while saving owners about $450 a year in fuel costs. According to a press release announcing the study, which was done by the National Renewable Energy Laboratory, in Golden, CO, and the utility company Xcel Energy, based in Minneapolis, although plug-in hybrids would draw power from the electricity grid, they would not necessarily increase the need for electrical infrastructure. That's because they could be recharged at night when much of the capacity of power plants isn't being used. Another study, by the Pacific Northwest National Laboratory, also suggests that plug-in hybrids could be charged using existing power plants, at least in most of the country. (See "How Plug-In Hybrids Will Save the Grid.")

Source : Technology Review

GM announces new battery technology for electric vehicule

General Motors (GM) recently announced that it is developing two types of plug-in hybrid vehicles, cars designed to run exclusively or almost exclusively on electricity for daily commutes. (See "GM's New Electric Vehicle" and "GM's Plug-In Hybrid.") But the announcements came with this caveat: the battery technology isn't ready, and production will have to wait. In reality, the battery technology is actually quite close to being ready.

Indeed, GM's vehicle chief engineer, Nick Zelenski, says that individual batteries are already good enough. "We've got enough data at the cell level to feel that the technology is there," he says. What remains to be done is packaging the cells into large battery packs and testing them in actual vehicles. This will be a challenge, Zelenski says, since there is a big difference between using "a single cell and multiplying them all together to get the energy levels that we need for this type of vehicle." But according to development contracts GM recently signed with two groups of companies, such battery packs will be ready for testing in vehicles by the end of this year.

Making batteries for vehicles, especially plug-in hybrids, is very challenging. For accelerating and climbing hills, the battery pack has to deliver enough power to supply the electricity demand of several houses at once. The energy storage capacity required to give a vehicle a 40-mile range would be enough to power a laptop in continuous use for weeks. Yet the space on board for such a battery pack is limited. "What we need is a very reliable and long-lived battery that has also got quite high energy density so we can find a place for it in the car," says Peter Savagian, director of hybrid power-train systems at GM.

Developers also need to make packs that can survive extremes in temperature and constant vibrations on the road, and still last the life of a vehicle. And they have to make the batteries safe. Last year millions of laptops were recalled because of the danger of their batteries bursting into flame. A plug-in hybrid would have the equivalent of hundreds of laptop battery packs bundled together.

Remarkably, at the level of individual cells, many of these problems have already been addressed. Lithium-ion batteries have much higher capacity than the lead acid batteries used in electric cars in the past, and even more than the nickel-metal hydride used in hybrids today. According to GM, its new Chevrolet Volt concept vehicle stores the same amount of energy as the company's EV-1 electric vehicle, but in just one-third the area. And while lead acid battery packs have to be replaced every couple of years, new lithium-ion batteries seem from lab tests to be able to last 10 years or more.

New lithium-ion batteries are also safer and less expensive than those in a laptop. One of the companies under contract with GM to develop battery packs is A123 Systems, based in Watertown, MA. It has developed a nanostructured iron phosphate­-­based electrode that is much safer than the cobalt-oxide laptop batteries that were recalled last year. For example, while a cobalt-oxide battery will burst into flame if punctured by a nail, the A123 battery merely releases innocuous wisps of steam. (See "Safer Lithium-Ion Batteries.") A123 is already producing millions of its batteries for use in professional power tools, and now it has developed a new, larger cell designed to be more rugged and hold more energy. The company has also modified the electrolyte to make the battery able to operate very well at -20 ˚F or temperatures up to 140 ˚F. As a result, "the car can operate in Scandinavia, in Patagonia, or in the summer in the middle of a tropical city," says Ric Fulop, cofounder and vice president of business development at A123 Systems.

At this point, cost may still be an issue. But that will change as more of the cells get made. "At the end of the day, it's a scale game," says Alan Mumby, CEO of a joint venture between Johnson Controls, in Milwaukee, WI, and Saft, in Paris, France. The venture has been awarded one of the two contracts for developing battery packs for GM .

Overall, "the fundamental tool kit--the weight, volumetric efficiency, the demonstration of life in a lab basis, and safety through extensive testing--have all

been demonstrated," says David Vieau, president and CEO of A123 Systems. "So this is not a pie in the sky. However, the actual execution of all functionality in cells in actual vehicles hasn't been done."

Although integrating the batteries into large packs is a challenge, in fact it has been done before. According to Scott Lindholm, vice president of systems engineering at Cobasys, based in Orion, MI, which is teaming with A123 Systems on the GM contract to develop battery packs, many of the problems involved in making lithium-ion battery packs are similar to those the company has already solved for the nickel-metal hydride packs it already produces for GM hybrids. What's more, several companies have already made large lithium-ion battery packs for vehicles. For example, Hymotion, based in Ontario, has used A123's power-tool batteries to make kits for converting the Toyota Prius into a plug-in hybrid. Indeed, its design is one of the contenders for converting hundreds of New York State's government-owned hybrids into plug-in hybrids. These packs are smaller than that used in GM's Volt concept vehicle, but companies such as Tesla Motors have already successfully engineered lithium-ion packs that are a few times larger than GM's pack.

The question is whether such packs can be engineered to have the life, safety, and cost that GM wants. As it is, these battery packs can cost tens of thousands of dollars, placing them out of the range of most consumers. But part of the cost has to do with scale, and that should change if GM puts the vehicle into production. The price is also coming down as the batteries are used in other applications, such as power tools.

In all, it seems as though battery technology is falling into place, just as demand for more fuel-efficient cars is rising. "It's really exciting for us to be in this business," says Fulop. "The timing ended up quite nice. We developed these products, and the plug-in-hybrid thing is really happening."

US Department of Energy considers that plug-in hybrid could save the grid

Major automakers and the Department of Energy are pouring money into research on plug-in hybrid vehicles. These cars promise to cut petroleum consumption by allowing commuters to drive to work using primarily electricity--stored on board in batteries--rather than gas. Although critics have warned that the vehicles could put too much pressure on an already strained electrical grid, experts are now arguing that rather than being a strain on the grid, plug-in hybrids may actually help prevent brownouts, cut the cost of electricity, and increase the use of renewable energy.

Plug-in hybrids, like today's hybrid cars, can run on either an electric motor or an internal combustion engine. But plug-ins have much larger battery packs and can be recharged by being plugged into the wall, making it possible to rely much more on the electric motor. Although a handful of companies sell conversion kits to change conventional hybrids into plug-ins, the kits add thousands of dollars to the cost of the car (see "Plug-In Hybrids Are on the Way"). This additional cost, which is primarily from the batteries, is one of the reasons the major automakers haven't yet mass produced such vehicles, although they are now developing them. GM, for example, recently committed to making a plug-in version of a Saturn SUV (see "GM's Plug-In Hybrid").

The concern is that plug-ins are not a good way to reduce gasoline consumption, because if they become popular, and millions of car owners recharged their cars at three in the afternoon on a hot day, it would crash the grid. But plug-in hybrids could actually help stabilize the grid if owners charged their cars at times of low demand, and if the vehicles could return excess energy to the grid when it's needed--say while parked in the company lot at work during peak demand.

Since utilities have built enough power plants to provide electricity when people are operating their air conditioners at full blast, they have excess generating capacity during off-peak hours. As a result, according to an upcoming report from the Pacific Northwestern National Laboratory (PNNL), a Department of Energy lab, there is enough excess generating capacity during the night and morning to allow more than 80 percent of today's vehicles to make the average daily commute solely using this electricity. If plug-in-hybrid or all-electric-car owners charge their vehicles at these times, the power needed for about 180 million cars could be provided simply by running these plants at full capacity.

This could be a boon to utilities, because they'd be able to sell more power without the added cost of building more plants. Ideally, this will translate into lower electricity prices, says Robert Pratt, a scientist at PNNL. It might also help utilities justify the added capital costs of building cleaner coal-burning plants, because they'll be able to recover their investment faster by "selling more electricity with the same set of iron, steel, and concrete," Pratt says.

Such a system could be further optimized by using smart chargers and other electronics. This system would include a charger that runs on a timer, charging cars only during off-peak hours. Researchers at PNNL are taking this a step further with smart chargers that use the Internet to gather information about electricity demand. Utilities could then temporarily turn off chargers in thousands of homes or businesses to keep the grid from crashing after a spike in demand.

The next step would be to add smart meters that would track electricity use in real time and allow utilities to charge more for power used during times of peak demand, and less at off-peak hours. Coupled with such a system, the PNNL smart charger could ensure that the plug-in batteries are charged only when the electricity is at its cheapest, saving consumers money.

But what many experts are excited about now is a concept called "vehicle-to-grid," often abbreviated V2G. In such a system, plug-in hybrids, rather than being merely an extra burden to the grid, become a much needed way for grid managers to balance the amount of energy generated at any given time to match the amount of energy being consumed. Millions of cars, each with several kilowatt hours of storage capacity, would act as an enormous buffer, taking on charge when the system temporarily generates too much power, and giving it back when there are short peaks in demand.

In a V2G system, the batteries of millions of plug-ins would be used as a buffer to even out supply and demand and to help keep the grid stable, says Karl Lewis, chief operating officer of GridPoint, a startup based in Washington, D.C., that has developed technology that could help make such a system work. In this kind of system, each vehicle would have its own IP address so that wherever it is plugged in, the cost of the energy it uses to recharge would be billed to the owner. With the right equipment, the car could also return energy to the grid, giving the owner credit. Mock-ups of such systems have already been tested by the National Renewable Energy Laboratory (NREL), in Golden, CO, and by a company called AC Propulsion, based in San Dimas, CA.

Plug-ins could also serve as backup sources of power. In extreme cases, such as a blackout from a hurricane, the cars could keep essential systems up and running in homes and businesses. Even in this case, when the batteries could be drawn down considerably, the owner could rely on the internal combustion engine in a plug-in hybrid for transportation.

As an added benefit, "if millions of these [plug-in hybrids] were produced, it would enable some of the renewable technologies to really take off," say Terry Penney, a technology manager for advanced vehicle technologies at NREL. The challenge of using a renewable source such as wind is that wind is intermittent, varying day by day and minute by minute. A network of plug-in hybrids could smooth out these fluctuations by storing extra energy and sending it to the grid when the wind dies down. Such a network would also improve the economics of wind power by making it possible to capture more of the excess power generated on windy days, says Willett Kempton, senior policy scientist in the Center for Energy and Environmental Policy at the University of Delaware.

Such systems are many years off, as it will take time to install the needed infrastructure. Once plug-in cars are widely available, however, they could help relieve some of the pressure on the grid today.

 

Source : Technology Review

GM announces a new plug-in hybrid vehicle

Last week General Motors (GM) gave a boost to plug-in hybrid vehicles. It announced a new gas-saving technology that could transform transportation and make renewable sources of electricity, such as wind and sun, more feasible.

At the Greater Los Angeles Auto Show, the automaker committed to manufacturing versions of its hybrid Saturn Vue SUV with a much larger battery pack that can be charged via an ordinary household socket. The increased size of the battery pack makes it possible to rely more on electric drive than current hybrid vehicles do, thereby saving much more gasoline. The actual rollout date will depend on the development of suitable battery technology, according to GM chairman and CEO Rick Wagoner.

With the announcement, GM joined other major automakers that are developing plug-in hybrid technology, including Ford, Daimler Chrysler, and Toyota. "We hope to have some products in the near future, but we're not prepared to say yet when that will be," says Bruce Brownlee, the senior executive administrator at Toyota Technical Center, in Gardena, CA. "The potential [of plug-in hybrids] is terrific." (None of these car companies have yet committed to widespread production of such a vehicle.)

The announcement marks a change in strategy for GM, which has previously focused on addressing environmental issues and high fuel prices by modifying existing vehicles to run on ethanol and by developing hydrogen fuel-cell vehicles. Although GM still plans to continue its fuel-cell program, the decision to produce plug-in hybrids represents a move toward a more evolutionary transition from internal combustion vehicles. "It's nice to see General Motors not just putting all their bets on hydrogen," says Jason Mark, vehicles director for the Union of Concerned Scientists, based in Cambridge, MA.

Plug-in hybrids, which use both an electric motor and a gasoline-powered internal combustion engine, have been hailed as a bridge technology that could make it possible to cut gasoline consumption in the short term; meanwhile, researchers will continue to work out the problems with all-electric vehicles, such as the high costs that make long-range battery-powered vehicles unaffordable. The most commonly described version of this technology would allow drivers to commute about 20 miles without using gasoline at all. But in reality, plug-in hybrids will likely use a blended strategy, relying on the gasoline engine to boost power for acceleration or for climbing hills even during the first 20 miles. This blended strategy would still mean that a typical commute would use almost no gasoline. "Having an internal combustion engine for passing or hill climbing is probably a prudent thing to do," says Thomas Keim, a principal research engineer at MIT. "But if you're traveling around town or just cruising on the highway, you can do both of those things from the battery."

Plug-in hybrids have an advantage over all-electric vehicles in that the battery would be the primary source of power only for relatively short distances, allowing for a much smaller and less expensive battery pack. Since short trips represent the majority of driving in the Unites States, the result would be a dramatic decrease in gasoline use. Electricity use would go up, but the price of powering a vehicle with electricity from the grid during off-peak hours would be the equivalent of gas for about 90 cents per gallon, says Terry Penney, a technology manager for advanced vehicle technologies at the National Renewable Energy Laboratory, in Golden, CO.

For longer trips, the vehicle would switch to a standard hybrid mode once the battery has been depleted to a certain point, saving fuel the same way today's hybrids do. This includes using energy recaptured from braking, turning off the engine when the vehicle stops, and allowing the gasoline engine to run at a more constant and efficient speed. Incorporating existing technologies--such as six-speed rather than four-speed automatic transmissions, and turning off fuel to pistons that aren't needed--could further improve fuel efficiency. Indeed, Mark says these technologies alone, even without hybrid technology, could improve average fuel economy by 10 miles per gallon--enough to replace all the oil we import from the Middle East. Using ethanol rather than gasoline could further decrease gasoline consumption.

These fuel savings would only be the beginning, many experts say. As battery technology improves, and if plug-in hybrids are successful, the high-volume production of batteries could lower their price. This would make it affordable to increase battery-pack size in successive generations and rely even less on gasoline. Eventually, the internal combustion engine could be made smaller and be used exclusively to recharge the batteries on long trips in a configuration called a "series" hybrid. "As time goes on, we may look at even more electrification of the vehicle, including solutions that use fuel cells," says Peter Savagian, director of hybrid power-train systems at GM. At some point, the internal combustion engine could be replaced entirely by large electric motors and battery packs, or by hydrogen fuel cells.

But plug-in hybrids still face challenges. Their environmental benefits will depend on the source of electricity used to charge the batteries. In areas powered primarily by coal, a plug-in might not be better for the environment than a good hybrid, says Nicholas Twork, a spokesman for Ford. Penney says that plug-ins will typically be better, however, since other areas in the United States rely on cleaner sources of electricity.

What's more, Penney says, "if millions of these things were produced 20 years from now, it would really enable renewable energies like wind to take off." Wind power requires ways of storing energy generated when demand for electricity is low, he says. The cost of the storage makes it hard for wind to compete with other sources of electricity. Millions of plug-in vehicles charging at night would essentially provide free storage.

But right now the biggest challenge to plug-in hybrids is the battery technology. First, batteries are expensive. Several companies sell kits for converting existing hybrids to plug-ins with larger battery packs, and these can add $10,000 to the price of a car (see "Plug-In Hybrids Are on the Way"). The plug-in hybrid application will also be much more demanding on batteries than ordinary hybrids are. In a car such as the Toyota Prius, the battery stays at about a 50 percent state of charge, and this varies only a few percent as it absorbs power from regenerative breaking and delivers it in short bursts to augment the gas engine. With plug-ins, batteries will be charged up to at least 95 percent and then deeply discharged during the first 20 miles of driving before settling into an ordinary hybrid mode. Such deep discharging typically decreases battery life. Automakers want batteries that can last 10 years or so even under these conditions so that consumers won't need to buy new battery packs a few years into owning a vehicle.

Automakers' newfound interest in plug-in hybrids is due in part to promising new battery technologies that could be less expensive and have longer lifetimes, and in part to their being safer than the lithium-ion batteries used in laptops today (see "Safer Lithium-Ion Batteries"). "We're encouraged by the improvements in the technology represented by hybrid batteries today," Savagian says. "And we're encouraged that there are many companies pursuing different formulas for them. But we want to give them cause to continue to press forward."

Source : Technology Review

The Material Research Society (MRS) promises batteries with double-capacity for electric vehicle

Today's battery technology is adequate for electric vehicles with a range of more than 200 miles, but the batteries are still very expensive and require elaborate safety mechanisms. There are also concerns that they won't last long enough to be attractive to most consumers.

But current research will double energy-storage capacity while also increasing the lifetime of batteries, improving safety, and cutting costs more than enough to make electric vehicles and plug-in hybrids practical for the mass market. At least these were the predictions of researchers presenting their latest work at the Materials Research Society (MRS) meeting in Boston this week. And although many significant challenges remain, an experimental type of rechargeable battery that's like a fuel cell could increase battery storage that much more.

Stanley Whittingham, inventor of the first commercial lithium-ion battery and professor of chemistry, materials science, and engineering at the State University of New York, at Binghamton, says current research should make electric vehicles practical--with the following caveat: they'll probably be used for trips of less than 100 miles. Those who want 300-to-400-mile ranges typical of gasoline-powered vehicles will need to turn to plug-in hybrids: vehicles much like today's gas-electric hybrids, but with a much larger battery pack that makes it possible to go longer on electric power, thereby saving gas. These batteries could be partly charged by an onboard gas engine, but also by electricity from a wall socket.

Whittingham says that while he expects battery capacity to double, it's not going to get much better than that. The real advances in batteries, he says, won't be in energy capacity, but in safety, longevity, and cost. If electric vehicles are to be widespread, one of the most important goals of battery research must be to replace the cobalt now used in the lithium-ion batteries found in cell phones and laptops. "There's just not enough [cobalt] in the world," says Whittingham, who is working on mixed-metal electrodes, which require little to no cobalt.

One promising new type of battery, which actually has lower storage capacity than today's lithium-ion batteries, could nevertheless prove a boon to plug-in hybrids. Lithium iron phosphate batteries use iron, a very cheap metal, instead of cobalt, and they have an inherently safe chemistry (see "Safer Lithium-Ion Batteries"). What's more, they operate at a lower voltage that will extend the life of the electrolyte, and therefore the battery.

Yet-Ming Chiang, a MIT materials scientist, is developing even better versions of these batteries. Typically when designing batteries engineers have to choose between high-power batteries, such as those needed for power tools and hybrids, which deliver intense bursts of power, and high-energy batteries that pack less of a punch, but can deliver more total energy per charge. According to computer models created by Chiang's lab and presented at the MRS meeting, it may be possible to remove this trade-off by producing nanostructured electrodes made by combining two different types of particles in a specific arrangement in the electrode. This could as much as double energy capacity for high-power applications, without the need to develop new materials, Chiang says.

A researcher at the MRS meeting described another experimental way of creating new electrode structures--a way that could increase energy capacity over existing batteries by four times or more. Peter Bruce, professor of chemistry at the University of St. Andrews, in Scotland, is reviving interest in a type of battery that is something like a fuel cell. This battery has been widely used in the past, but making it rechargeable has proved difficult. Ordinarily, a battery contains all the materials needed to carry out its current-creating chemical reactions. But in this design, one of the reactants, oxygen, can be harvested from the air. As in a fuel cell, in which hydrogen ions combine with oxygen to form water, lithium ions in this battery combine with oxygen to form lithium peroxide. Using oxygen makes it possible to eliminate many of the materials normally included in a battery, drastically cutting its weight. Based on his experiments, Bruce says that such batteries could store as much as 600 to 700 milliamp hours per gram (more than four times that of batteries today) while maintaining the ability to be charged and discharged for many cycles.

So far, Bruce has conducted his experiments using pure oxygen. A working battery would need to be equipped with a membrane, which could be a material similar to Gore-Tex that would seal out both water and carbon dioxide, he says. It might also need a valve to shut off the supply of oxygen to keep reactions from occurring when no current is needed.

Perhaps a bigger problem is the fact that the batteries lose about half of their energy to heat as they are discharged, Whittingham says. This creates a big heat-management issue, and it cuts into the energy-saving motivation for driving hybrids or electric vehicles. "If [Bruce] can be successful, it would be great," he says. But even without such dramatic gains in energy capacity, current research could make batteries much more practical. "I expect the auto companies will be happy with two times [higher capacity] if it will last 10 years," Whittingham says.

Source : Technology Review

EEStor Inc. builds an energy storage device that could finally usher in the era of the electric car

Here is an interesting article about EEStor Inc, this canadian start-up company which is supposed to have developped a disruptive energy storage system for electric car. They have teamed up with another start-up company, Feel Good Cars Corp, to promote ZENN, a zero emission new concept car. But, above all, EEStor would have received a $3m investment from Kleiner Perkins...

Anyway, it seems that many questions remain about their genuine technical achievements.

Interesting to follow.

Nanotecture et HILTech développent des super-condensateurs pour les véhicules hybrides

Un consortium, composé des compagnies britanniques Nanotecture, Johnson Matthey et HILTech Developments, a reçu un financement de 375.000 livres (environ 547.000 euros) du Department of Trade and Industry (DTI, ministère du Commerce et de l'Industrie) pour le projet de R&D "Next Generation Super-capacitors for Hybrid Vehicle Application" (nouvelle génération de super-condensateurs pour les véhicules hybrides). Ce projet de 2 ans va permettre de combiner les compétences des différentes entreprises : nanomatériaux pour Nanotecture, catalyseurs et métaux précieux pour Johnson Matthey, et les systèmes hybrides et super-condensateurs de HILTech Developments.
Les super-condensateurs sont des appareils de stockage de l'énergie capable de fournir des salves de très hautes puissances avec des temps de rechargement très rapides. Dans le cas des véhicules hybrides et électriques, ils sont nécessaires pour fournir suffisamment de puissance au moteur lors des phases d'accélération. De plus, ils permettent d'améliorer l'efficacité du véhicule à l'aide de mécanismes comme le freinage rétroactif (récupérer l'énergie perdue lors du freinage du véhicule pour la stocker dans le condensateur). Le super-condensateur ne stocke pas autant d'énergie qu'une batterie mais il la délivre beaucoup plus vite. Cependant, les super-condensateurs actuels ont une faible capacité énergétique et sont chers à fabriquer.
Les matériaux de Nanotecture sont nanoporeux, ce qui permet aux réactions chimiques impliquées d'avoir lieu plus rapidement. Combiné avec les technologies de catalyse et des condensateurs de Johnson Matthey et de HILTech Developments, la capacité énergétique du super-condensateur devrait augmenter significativement.
Le consortium espère avoir un prototype opérationnel avant la fin du projet (février 2008) pour tester le système à des régimes moteurs spécifiques. Cependant, ils ont pour objectif d'équiper des bus et des systèmes automobiles pour d'autres tests dans 15 mois (mai 2007).