Fraggle145
12/2/2008, 04:16 PM
I found this article in Nature News to be interesting... thought i'd share.
Published online 26 November 2008 | Nature 456, 436-440 (2008) | doi:10.1038/456436a (http://www.nature.com/news/2008/081126/full/456436a.html)
A new generation of lithium-ion batteries, coupled with rising oil prices and the need to address climate change, has sparked a global race to electrify transportation. Jeff Tollefson investigates.
Jeff Tollefson
"We have had a massive shift in one of the biggest industries in the world," says Stephan Dolezalek, who leads the CleanTech group at the venture-capital firm VantagePoint Venture Partners in San Bruno, California. Dolezalek has been watching the global automobile sector embrace the idea of plug-in electric cars: "In three years we've gone from thinking 'it can't be done' to not only 'it can be done' but 'we are all going to do it.'"
The shift is partly a story of technological innovation, which has produced rechargeable batteries that pack enough power to propel some of the basic passenger vehicles currently being designed further than 200 kilometres. Billions of dollars have poured into start-up companies that promise new batteries, and billions more have poured into fledgling electric-car manufacturers eager to take on the global automotive giants — every one of which is also developing electric vehicles.
The shift is also a story of oil supplies, national security and global warming. Record-high oil prices have pushed consumers towards fuel-efficient vehicles and prompted many governments to consider electric transport as a way to escape their dependence on imported petroleum and to address climate change. Money currently spent abroad could instead be spent on domestic power generation from wind, solar and other low-carbon energy sources.
And the shift is a story of a shared vision: developing the technology that would entice all drivers to plug in rather than fill up. Millions of battery-powered cars plugged into an increasingly green electric grid would not only save drivers money and reduce greenhouse-gas emissions, it would also provide the grid with a distributed, high-capacity storage system for electricity. Such a system would help to accommodate the variable and unpredictable nature of renewable electricity sources. And further out, it could allow power companies to store energy generated during times of low demand, then draw it back again to meet peak demand. The end result could be more a stable and efficient grid that might even lower home electricity bills.
Getting there won't be easy. All these hopes hinge on battery technology that is only just emerging from the lab. A suite of technical challenges remains to be overcome, and it is not yet clear how much further the technology can be pushed. At the same time, the manufacturers who are arguably best able to bring about these changes — the global automotive giants — have been hammered by an energy crisis followed by an epic financial meltdown.
None of them has abandoned the effort yet, in large part because they all believe that, despite the current lull, oil prices have nowhere to go but up. Moreover, batteries have leapt ahead of expensive hydrogen fuel cells as the technology of choice for getting beyond oil, at least for now. But the field is wide open in terms of bringing them to market. Dolezalek believes that major car companies might well perish in the face of versatile young upstarts, and he isn't alone. The automobile industry secured a place in this autumn's first round of economic bailouts from the US government with US$25 billion in loan guarantees for retooling its plants, and it is already seeking more. That has people such as Andrew Grove, former chairman of Intel, who has become a leading proponent of electric transportation, talking about the 'valley of death' that often accompanies a massive technological transformation. Grove says that car manufacturers have already begun their march through the valley, knowing that many won't make it through to the other side.
"The only time people make these moves [through the valley] is when things are rough, but they can't afford to make them when times are rough," Grove says. And that means that governments might have to step in. "I just hope that it's going to be done in such a way that the government says, 'I'll give you some water and food to get through the valley of death, but don't turn back.'"
Building a better battery
Pioneers have turned back before, most notably General Motors. In 1996, the US company released the EV-1, the first all-electric car from a major manufacturer. The vehicle was expensive, rolled out in response to a California mandate, which was later rescinded, for 2% of all cars sold in the state to have zero-emissions by 1998. But its fate was ultimately sealed by one thing: its battery.
http://www.nature.com/news/2008/081126/images/456436a-i4.0.jpg
Building batteries has been an exercise in chemical compromise for more than two centuries. The idea is simple: chemical bonds can be used to trap ions in one electrode. When a battery is hooked up to a circuit, the ions flow through a separator to a second electrode; as the ions flow, they release electrons, generating an electric current. In rechargeable batteries, the chemical reaction can be reversed to store energy (see graphic, right). But the reality is complex: although scientists have produced numerous potential battery chemistries (see Nature 451, 652–657; 2008), none of them performs well on all the crucial factors of cost, safety, durability, power and sheer capacity.
The first-generation EV-1 deployed a lead-acid battery, still the technology of choice for conventional vehicles. Lead-acid batteries are safe, cheap, long-lived and reliable, but they are also big and heavy. They could push the car for about 150 kilometres per charge. A second-generation vehicle released in 1999 featured a nickel metal hydride battery, and travelled 50% farther on a charge, but General Motors cancelled them after the first year, saying that it could not sell enough to make them profitable.
http://www.nature.com/news/2008/081126/images/456436a-i3.0.jpg
It was a decision that General Motors would come to regret. As it turned back to large and profitable vehicles such as the Hummer, its up-and-coming Japanese rival Toyota was digging into the new technology, using the same battery that General Motors had abandoned to produce hybrid cars that combined a standard combustion engine with an electric motor. Toyota has gone on to set the standard for hybrids: its third-generation Prius has been immensely popular, proving that consumers will adopt advanced battery technology in automobiles if it is done well. The Prius fortified Toyota's reputation, and helped it to surpass General Motors last year to become the largest automobile manufacturer in the world.
But nickel metal hydride batteries can be developed only so far. These batteries pack more power than standard lead-acid ones but can be permanently damaged if allowed to discharge too far. To maintain an adequate safety margin, Toyota limited the Prius to using about 20% of its battery charge during normal operation. But although not using 80% of the capacity is acceptable if the battery is simply supplementing a petrol engine, it is a luxury that fully electric cars can't afford. Electric cars need all the charge they can get, and that means new chemistries.
Lithium-ion batteries, which are compact and have a high capacity, are a natural place to start. Sony paved the way with the lithium cobalt oxide battery, which made its mass-market debut in a 1991 version of the firm's HandyCam video camera, and is now widely used in consumer electronics. Lithium is a light metal, and the lithium cobalt oxide lattice structure allows plenty of space for the give and take of ions. But scaling this chemistry up for vehicles is problematic. Cobalt is expensive and toxic, and the batteries have been known to show 'thermal runaway', battery lingo for fires or explosions. "It has affected a tiny, tiny fraction of all of the batteries sold, but nonetheless, it's pretty freaky to think about a big fire in one of the vehicles," says Jeff Dahn, who works on advanced battery technology at Dalhousie University in Halifax, Canada. "Safety really needs to be the focus for the research community."
Many of the lithium batteries under development for vehicles replace cobalt oxides with manganese oxides and iron phosphates. Both are safer, but they do have their own problems, not least of which is a lower storage capacity for their size. Another challenge has been dealing with the physical expansion and contraction of the electrode material as the lithium ions flow back and forth during charge and discharge, which can lead to fractures. Researchers at multiple institutions have addressed the issue by adding carbon and other substances to the electrode material.
They are also probing other chemistries — often at the nanoscale — based on silicon, fluorides and oxygen, which have a greater capacity. Others are looking at equipping the battery pack with capacitors, which can rapidly store and discharge electricity.
Even in their current state, however, lithium-ion batteries are performing well enough to keep car manufacturers interested. Last year, General Motors inaugurated the race for mass-market electric vehicles when it announced plans to market its plug-in hybrid, the Chevrolet Volt.
http://www.nature.com/news/2008/081126/images/456436a-i1.0.jpg
A break with the past
The Volt, now scheduled for a 2010 roll-out, is a radical shift in design. Hybrids such as the Prius are powered by petrol, and use a battery simply to improve fuel efficiency. The Volt hybrid will be the reverse: an electric car that uses petrol to extend its range. Only when the charge dies will a small petrol motor kick in to charge the battery, which then continues to power the vehicle. The goal is for Volt owners to plug in at night and then drive more than 60 kilometres a day on a single charge — before burning a single drop of petrol. Given that as many as 80% of US drivers commute less than that on an average day, such vehicles could eliminate a sizeable chunk of the nation's oil consumption.
The Volt initiative could open the door to a new kind of transportation system — if the company can pull it off, both on time and at a cost that will tempt consumers. Many observers have their doubts. "They are fundamentally redefining what a car is, but can they do it? I don't know," says Don Hillebrand, who heads the Center for Transportation Research at Argonne National Laboratory in Illinois. "When the first generation of anything comes out, to a certain extent car manufacturers are rolling the dice, and this is the biggest roll of the dice anybody has ever made."
Some say it is a long shot. With sales plummeting in the midst of a deepening recession, the company is facing possible bankruptcy, and has joined with the other major US car manufacturers in seeking an additional bailout from the government. But through it all, General Motors has continued to sink everything it can spare into the Volt, viewing it as a key technology that would allow the company to leapfrog its competitors.
Toyota is taking a more measured approach with its plug-in hybrid, which is expected to roll out with a lithium-ion battery in 2009. John Hanson, a spokesman based at Toyota's US headquarters in Torrance, California, talks about managing customer expectations: the company is promising only that the vehicle will go "at least" 16 kilometres on an electric charge. After that, it will blend petrol and electric power in much the same way as the current Prius.
That would leave General Motors in pole position, at least in terms of the electric range it is promising. But will the Volt succeed? The answer to that question depends on consumers. What will they want several years from now? And how much will they be willing to pay? General Motors expects to lose money in the beginning and has not yet announced a price for the vehicle, but the continued viability of the firm could depend on how fast it can sell the new cars and at what price. The company is banking on tax credits, enacted this year by Congress, to encourage people to buy plug-in hybrids, and high petrol prices would help as well.
But the firm's chief economist Mustafa Mohatarem says that he can't help but wonder whether consumer demand for electric vehicles has been exaggerated. "It is critically dependent on the battery," he says. "Until you have a much better handle on the cost of this technology, to talk about demand is in a sense ridiculous."
Published online 26 November 2008 | Nature 456, 436-440 (2008) | doi:10.1038/456436a (http://www.nature.com/news/2008/081126/full/456436a.html)
A new generation of lithium-ion batteries, coupled with rising oil prices and the need to address climate change, has sparked a global race to electrify transportation. Jeff Tollefson investigates.
Jeff Tollefson
"We have had a massive shift in one of the biggest industries in the world," says Stephan Dolezalek, who leads the CleanTech group at the venture-capital firm VantagePoint Venture Partners in San Bruno, California. Dolezalek has been watching the global automobile sector embrace the idea of plug-in electric cars: "In three years we've gone from thinking 'it can't be done' to not only 'it can be done' but 'we are all going to do it.'"
The shift is partly a story of technological innovation, which has produced rechargeable batteries that pack enough power to propel some of the basic passenger vehicles currently being designed further than 200 kilometres. Billions of dollars have poured into start-up companies that promise new batteries, and billions more have poured into fledgling electric-car manufacturers eager to take on the global automotive giants — every one of which is also developing electric vehicles.
The shift is also a story of oil supplies, national security and global warming. Record-high oil prices have pushed consumers towards fuel-efficient vehicles and prompted many governments to consider electric transport as a way to escape their dependence on imported petroleum and to address climate change. Money currently spent abroad could instead be spent on domestic power generation from wind, solar and other low-carbon energy sources.
And the shift is a story of a shared vision: developing the technology that would entice all drivers to plug in rather than fill up. Millions of battery-powered cars plugged into an increasingly green electric grid would not only save drivers money and reduce greenhouse-gas emissions, it would also provide the grid with a distributed, high-capacity storage system for electricity. Such a system would help to accommodate the variable and unpredictable nature of renewable electricity sources. And further out, it could allow power companies to store energy generated during times of low demand, then draw it back again to meet peak demand. The end result could be more a stable and efficient grid that might even lower home electricity bills.
Getting there won't be easy. All these hopes hinge on battery technology that is only just emerging from the lab. A suite of technical challenges remains to be overcome, and it is not yet clear how much further the technology can be pushed. At the same time, the manufacturers who are arguably best able to bring about these changes — the global automotive giants — have been hammered by an energy crisis followed by an epic financial meltdown.
None of them has abandoned the effort yet, in large part because they all believe that, despite the current lull, oil prices have nowhere to go but up. Moreover, batteries have leapt ahead of expensive hydrogen fuel cells as the technology of choice for getting beyond oil, at least for now. But the field is wide open in terms of bringing them to market. Dolezalek believes that major car companies might well perish in the face of versatile young upstarts, and he isn't alone. The automobile industry secured a place in this autumn's first round of economic bailouts from the US government with US$25 billion in loan guarantees for retooling its plants, and it is already seeking more. That has people such as Andrew Grove, former chairman of Intel, who has become a leading proponent of electric transportation, talking about the 'valley of death' that often accompanies a massive technological transformation. Grove says that car manufacturers have already begun their march through the valley, knowing that many won't make it through to the other side.
"The only time people make these moves [through the valley] is when things are rough, but they can't afford to make them when times are rough," Grove says. And that means that governments might have to step in. "I just hope that it's going to be done in such a way that the government says, 'I'll give you some water and food to get through the valley of death, but don't turn back.'"
Building a better battery
Pioneers have turned back before, most notably General Motors. In 1996, the US company released the EV-1, the first all-electric car from a major manufacturer. The vehicle was expensive, rolled out in response to a California mandate, which was later rescinded, for 2% of all cars sold in the state to have zero-emissions by 1998. But its fate was ultimately sealed by one thing: its battery.
http://www.nature.com/news/2008/081126/images/456436a-i4.0.jpg
Building batteries has been an exercise in chemical compromise for more than two centuries. The idea is simple: chemical bonds can be used to trap ions in one electrode. When a battery is hooked up to a circuit, the ions flow through a separator to a second electrode; as the ions flow, they release electrons, generating an electric current. In rechargeable batteries, the chemical reaction can be reversed to store energy (see graphic, right). But the reality is complex: although scientists have produced numerous potential battery chemistries (see Nature 451, 652–657; 2008), none of them performs well on all the crucial factors of cost, safety, durability, power and sheer capacity.
The first-generation EV-1 deployed a lead-acid battery, still the technology of choice for conventional vehicles. Lead-acid batteries are safe, cheap, long-lived and reliable, but they are also big and heavy. They could push the car for about 150 kilometres per charge. A second-generation vehicle released in 1999 featured a nickel metal hydride battery, and travelled 50% farther on a charge, but General Motors cancelled them after the first year, saying that it could not sell enough to make them profitable.
http://www.nature.com/news/2008/081126/images/456436a-i3.0.jpg
It was a decision that General Motors would come to regret. As it turned back to large and profitable vehicles such as the Hummer, its up-and-coming Japanese rival Toyota was digging into the new technology, using the same battery that General Motors had abandoned to produce hybrid cars that combined a standard combustion engine with an electric motor. Toyota has gone on to set the standard for hybrids: its third-generation Prius has been immensely popular, proving that consumers will adopt advanced battery technology in automobiles if it is done well. The Prius fortified Toyota's reputation, and helped it to surpass General Motors last year to become the largest automobile manufacturer in the world.
But nickel metal hydride batteries can be developed only so far. These batteries pack more power than standard lead-acid ones but can be permanently damaged if allowed to discharge too far. To maintain an adequate safety margin, Toyota limited the Prius to using about 20% of its battery charge during normal operation. But although not using 80% of the capacity is acceptable if the battery is simply supplementing a petrol engine, it is a luxury that fully electric cars can't afford. Electric cars need all the charge they can get, and that means new chemistries.
Lithium-ion batteries, which are compact and have a high capacity, are a natural place to start. Sony paved the way with the lithium cobalt oxide battery, which made its mass-market debut in a 1991 version of the firm's HandyCam video camera, and is now widely used in consumer electronics. Lithium is a light metal, and the lithium cobalt oxide lattice structure allows plenty of space for the give and take of ions. But scaling this chemistry up for vehicles is problematic. Cobalt is expensive and toxic, and the batteries have been known to show 'thermal runaway', battery lingo for fires or explosions. "It has affected a tiny, tiny fraction of all of the batteries sold, but nonetheless, it's pretty freaky to think about a big fire in one of the vehicles," says Jeff Dahn, who works on advanced battery technology at Dalhousie University in Halifax, Canada. "Safety really needs to be the focus for the research community."
Many of the lithium batteries under development for vehicles replace cobalt oxides with manganese oxides and iron phosphates. Both are safer, but they do have their own problems, not least of which is a lower storage capacity for their size. Another challenge has been dealing with the physical expansion and contraction of the electrode material as the lithium ions flow back and forth during charge and discharge, which can lead to fractures. Researchers at multiple institutions have addressed the issue by adding carbon and other substances to the electrode material.
They are also probing other chemistries — often at the nanoscale — based on silicon, fluorides and oxygen, which have a greater capacity. Others are looking at equipping the battery pack with capacitors, which can rapidly store and discharge electricity.
Even in their current state, however, lithium-ion batteries are performing well enough to keep car manufacturers interested. Last year, General Motors inaugurated the race for mass-market electric vehicles when it announced plans to market its plug-in hybrid, the Chevrolet Volt.
http://www.nature.com/news/2008/081126/images/456436a-i1.0.jpg
A break with the past
The Volt, now scheduled for a 2010 roll-out, is a radical shift in design. Hybrids such as the Prius are powered by petrol, and use a battery simply to improve fuel efficiency. The Volt hybrid will be the reverse: an electric car that uses petrol to extend its range. Only when the charge dies will a small petrol motor kick in to charge the battery, which then continues to power the vehicle. The goal is for Volt owners to plug in at night and then drive more than 60 kilometres a day on a single charge — before burning a single drop of petrol. Given that as many as 80% of US drivers commute less than that on an average day, such vehicles could eliminate a sizeable chunk of the nation's oil consumption.
The Volt initiative could open the door to a new kind of transportation system — if the company can pull it off, both on time and at a cost that will tempt consumers. Many observers have their doubts. "They are fundamentally redefining what a car is, but can they do it? I don't know," says Don Hillebrand, who heads the Center for Transportation Research at Argonne National Laboratory in Illinois. "When the first generation of anything comes out, to a certain extent car manufacturers are rolling the dice, and this is the biggest roll of the dice anybody has ever made."
Some say it is a long shot. With sales plummeting in the midst of a deepening recession, the company is facing possible bankruptcy, and has joined with the other major US car manufacturers in seeking an additional bailout from the government. But through it all, General Motors has continued to sink everything it can spare into the Volt, viewing it as a key technology that would allow the company to leapfrog its competitors.
Toyota is taking a more measured approach with its plug-in hybrid, which is expected to roll out with a lithium-ion battery in 2009. John Hanson, a spokesman based at Toyota's US headquarters in Torrance, California, talks about managing customer expectations: the company is promising only that the vehicle will go "at least" 16 kilometres on an electric charge. After that, it will blend petrol and electric power in much the same way as the current Prius.
That would leave General Motors in pole position, at least in terms of the electric range it is promising. But will the Volt succeed? The answer to that question depends on consumers. What will they want several years from now? And how much will they be willing to pay? General Motors expects to lose money in the beginning and has not yet announced a price for the vehicle, but the continued viability of the firm could depend on how fast it can sell the new cars and at what price. The company is banking on tax credits, enacted this year by Congress, to encourage people to buy plug-in hybrids, and high petrol prices would help as well.
But the firm's chief economist Mustafa Mohatarem says that he can't help but wonder whether consumer demand for electric vehicles has been exaggerated. "It is critically dependent on the battery," he says. "Until you have a much better handle on the cost of this technology, to talk about demand is in a sense ridiculous."