Are We Entering the Age of Batteries?
Last week in Houston, Secretary of Energy Dr. Ernest Moniz told CERA Conference attendees that storage batteries may be the next big energy breakthrough. “It’s pretty dramatic,” he said. “The research is moving very, very fast.”
Indeed, if you’re looking for “energy breakthroughs” on the Internet these days, most of the hits are likely to turn up something new about “flow batteries,” “ten times the storage capacity,” or some new cathode material that dramatically improves the performance of lithium-ion batteries.
So where do we stand in this energy revolution now, and what are the possibilities that any of these breakthroughs are likely to lead to real improvements in our attempts to wean ourselves off traditional energy resources like fossil fuels?
A good place to start is “Next Generation Electrical Energy Storage: Beyond Lithium Ion Batteries,” a panel put together for last February’s meeting of the American Association for the Advancement of Science in Chicago. Three experts – Haresh Kamath; of the Electric Power Research Institute, Mark Mathias; of General Motors, and Jeff Chamberlain; of Argonne National Laboratory – discussed the latest developments in the industry.
All three panelists agreed that battery research is progressing along two separate tracks:
1) lithium-ion batteries that power most consumer electronic devices are now being scaled up for electric vehicles; and
2) larger and more durable conventional batteries for the storage of grid-scale electricity.
Despite whatever hopes Elon Musk may have that his new “Gigafactory” will be able to address both of these markets at the same time, that does not seem likely. “Lithium-ion just doesn’t have the durability that we’re looking for in the utility industry,” Kamath of EPRI told the audience. He continued:
I was doing cable research one time and we had a model for a product that would last 40 years. The utilities looked at it and said, `Could you try for 60 or 80?’ The utilities are looking for things that last a long, long time.’ said Kamath.
“There’s a lot of experimenting going on,” Kamath added, “but everything that is on the grid right now is a demonstration. No one has yet come up with a sustainable business model.”
With electric cars, on the other hand, the challenge will be in equipping batteries with enough energy density so that their weight does not load down the vehicle to the point of being counterproductive. “The standard measure is that you need 100 kilowatt-hours of power to drive a mid-sized vehicle 300 miles,” said Mathias, who works at GM’s electrical storage research and development project. He explained.
If you get up in the density range of 350 Watt-hours per kilogram, you can make it. But current batteries are operating at around 150 Wh/kg, which gives them a range of 125 miles. The best we can project is that they can achieve 225 Watt-hours per liter, which still leaves them short. (Mathias).
“Fuel cells operating on hydrogen actually do a much better job at this point,” he added. “They can now get us up in the 300-mile range. We regard them as electric vehicles as well. It’s just that you generate the electricity on board.”
Then there’s the matter of cost. Capital costs for lithium-ion batteries quickly rise into the $20,000 range. Fuel cells cost only $6,000 and gas-electric hybrids, $4,000. “The good news for EVs is that fuel costs are only about one-third that of gasoline,” said Mathias. “Over a span of 100,000 miles, a gasoline engine will cost you $10,000 in fuel. A hydrogen fuel cell vehicle will cost only $6,000 and a pure EV, $3,333.” Still, that’s a long time to wait and a long way from complete cost recovery.
Refueling time is also a bit of a problem. “When you pump gasoline into your car, you’re actually adding range at a rate of 150 miles per minute,” said Mathias. He went on to say:
With hydrogen fuel, it’s 100 miles-per-minute, which is acceptable. But even with the new 120-kW superchargers, you can only add mileage to an EV at a rate of 6 miles per minute. If you take a long- distance trip, you’re going to spend 20 percent of your time recharging. (Mathias)
Overall, Mathias was not overly optimistic about further improvements. “There’s not much on the horizon,” he concluded. He was more optimistic about hydrogen cars.
Chamberlain, of Argonne National Laboratory, is part of a $120 million program funded by the Department of Energy that is aimed at developing batteries with five times the current energy density at 1/5th the cost within five years. “That’s a very ambitious goal,” he told the audience, “but we feel that’s what’s needed to transform the transportation sector.” A long chain of national and university laboratories are involved in the project. Of course, government goals and mandates are just that – projections that may or may not come true. Steve Jobs was good at inspiring his cast to pursue seemingly impossible goals but the federal government does not always have the same success.
So far, the research has involved searching the periodic table for more candidates. “We’re not sure what we’re going to come up with,” said Chamberlain, elaborating:
We’ve decided that capacitors will never help us reach our goal. The charge dissipates too quickly. So we’re exploring other materials. It may involve a metallic anode and a suspended-particle cathode. If you move to magnesium or aluminum, you’re releasing two electrons instead of one. But zinc-air and lithium-air doesn’t get you there because they simply don’t have the power.” (Chamberlain)
Chamberlain said that a lot is already known about lithium-ion. “We may be able to get two times what we have now.” He had to agree with Mathias that no other significant developments are on the horizon right now.
Mathias warned against new reports that are constantly announcing progress at the material level. “We often realize right away that they’re not going to work,” he said. “It’s not worth the manufacturing dollars.
Overall, the takeaway from the panel was that Tesla has its work cut out for it. Progress on electric vehicles will be tough. The panelists agreed that natural gas vehicles make a lot of sense. “The problem is you don’t really solve the CO2 problem,” said Mathias. He did express confidence that battery research would eventually pay off in the end. “All this progress will eventually be harvested at the hybrid level,” he said. “It may not lead to pure electric level, but there is going to be a lot of improvement in hybrids.”