A 21st century electric-car revival is under way. But the first challenge—building a cheap, safe, powerful battery—is the hardest
The battery that will power the Chevrolet Volt weighs approximately 400 pounds and, stood on end, reaches a height of six feet. The $10,000-plus, T-shaped monolith contains 300 individual three-volt lithium-ion cells, bundled together in groups of three, then wired in series and kept from overheating by an elaborate liquid cooling mechanism. A computerized monitoring system inside the battery pack conducts this little electrical orchestra, coordinating the actions of the individual cells, balancing voltage, watching, above all, for any indication that a cell might be failing, shorting out, or otherwise threatening the stability of the system. This battery, one of the most advanced pieces of electrical storage equipment ever engineered, can propel the 3,520-pound Volt 40 miles before it runs out of energy.
And so can a gallon of gas.
Jon Lauckner would very much like for you to understand this. Lauckner is vice president for global program management at General Motors, a man with a self-professed strong bias toward the electrification of the automobile, and yet he wants you to realize exactly what electric cars are up against — to recognize that in the harsh, unsentimental view of an engineer, batteries, no matter how advanced they may seem, make gasoline look like a bargain.
“You,” in this scenario, are the members of a small group of journalists who have mingled their way through a GM cocktail reception in suburban Detroit in April to gather around Lauckner; tomorrow the group will tour the Warren, Michigan, facilities where the Volt is being developed, for a demonstration designed to prove that the plug-in hybrid’s long march to legitimacy is actively under way. It’s all very convivial, but Lauckner seems to be anticipating an ambush, nursing the certainty that someone will soon bring up the EV1, the electric car that GM launched in 1996 and, a few years later, infamously hauled en masse to the Arizona desert to be demolished. These days, as GM attempts to convince a skeptical world that its Volt is not, in fact, vaporware, the EV1 is a bit of a sore subject.
So before anyone can say a thing, Lauckner launches a preemptive strike, placing the blame for the EV1’s death squarely on the battery’s inability to compete with the internal combustion engine. “To anyone who thinks there was a conspiracy between GM and the oil companies to kill off the EV1,” he announces, gesturing toward open air, as if a life-size model of the Volt’s all-important battery pack stands beside him, “I say, this 400-pound battery” — at least 600 pounds lighter than the beast that powered the EV1 — “is still the equivalent of only a gallon of gasoline.”
Make no mistake, you will be able to buy some form of electrified car soon. It’s inevitable. Rising oil prices, melting polar ice caps, petroleum-fueled geopolitical insecurity — all send a pretty unambiguous message about fossil fuels: We need to stop using them. Americans burn 390 million gallons of gasoline every day, each of which pumps 20 pounds of carbon dioxide into the air. And right now, the alternative fuel with the best chance of rapidly shrinking that number is electricity. A hydrogen economy still might as well be science fiction. Corn-based ethanol may be driving up food prices worldwide, and it does nothing to lower carbon emissions. Electricity, on the other hand, is piped into every home in the country. It’s cheap compared with gasoline. It can come from almost any source — natural gas, coal, nuclear, hydroelectric, solar, wind. And a car fueled by even coal-derived electricity (the source of nearly half of America’s power) will generate only 0.7 pound of CO2 per mile for every pound of CO2 emitted by a conventional gasoline-powered car.
Today’s hybrid cars, like the Prius, are a small step toward the electrification of the automobile, but the emphasis is on small. Hybrids are, fundamentally, gas-powered cars that run on batteries for extremely short periods. Plug-in hybrids, however, or as GM calls the Volt, “extended-range electric vehicles” — cars with large batteries that charge straight from the grid and run the majority of the time on electricity, rather than gasoline — pass a critical threshold beyond which electricity, not oil, is the primary transportation fuel.
Consider the potential benefits. According to the Department of Transportation, 78 percent of Americans drive fewer than 40 miles a day, so most Volt drivers, for instance, would never use the car’s gas-powered backup engine on a normal driving day. Improve the battery technology enough to squeeze out an extra 10 miles per charge, and the numbers get even more impressive; a plug-in hybrid sedan with an all-electric range of 50 miles should average 150 mpg overall.
A study by the Electric Power Research Institute and the Natural Resources Defense Council found that even in a relatively pessimistic scenario, in which over the next four decades electricity continues to come mainly from coal, and plug-in hybrids make modest gains in market share, at least 3.4 billion metric tons of carbon emissions could be cut by 2050. To put that in perspective, the average midsize 30mpg car produces a little less than four tons of CO2 every year.
It will take a lot of cars to make that happen, but most automakers have begun at least making gestures at an electrified future. Nissan, Toyota, Mazda, Mini, Mitsubishi, Subaru, Hyundai and Volkswagen have all announced that they will release some sort of plug-in or electric car in the next two to three years, if only in limited batches. The boutique automaker Tesla has already begun delivering its pricey pure-electric sports cars, and other small operations, such as Fisker Coachbuild, have started taking orders for their own electrified automobiles.
Still, we’re far from having a battery that’s cheap, safe and energy-dense enough for electricity to displace gasoline completely. The Volt’s monstrous battery is a primitive ancestor of what automakers ultimately have in mind. Yet GM, the company whose reputation was all but ruined by the EV1 debacle, the overextended corporation that lost more than $15 billion in the second quarter of this year and could simply run out of cash by 2010, is essentially staking its continued existence on the Volt. It’s betting that the 400-pound battery it’s developing right now will eventually lead to the ubiquitous electric car of tomorrow.
High Wire: General Motors is staking its future on building the Volt plug-in hybrid
Anointing the vendor that will develop the miracle-box powerpack that could determine the fate of an entire company is not a decision to be made lightly. And so, for two weeks beginning in February 2007, delegations from eight battery manufacturers filed one after another, props and proposals in hand, into the massive glass-walled Vehicle Engineering Center on General Motors’s Warren Tech Center campus. Start-ups and multinational giants alike, these companies had survived the initial cut in the Volt battery-supplier derby, a baroque process in which some 20 employees across almost every GM division, from engineering to finance, spent two months scrutinizing 27 proposals. They graded each company’s batteries on energy and power density, temperature performance, safety, life span and cost. They weighted each metric by importance and factored in what Volt vehicle-line executive Tony Posawatz diplomatically calls “qualitative factors,” such as, Are we going to hate working with these guys? Next, 30 reviewers voted on which ones to bring in and grill in a marathon series of four-hour pitch sessions.
Each supplier was in Warren to prove that its battery could do the following: Store 16 kilowatt-hours of energy. Drive the Volt 40 miles on electricity alone. Launch the car from 0 to 60 in eight seconds. Run for at least 10 years. Withstand 5,000 full discharges and lose just 10 percent of its charge capacity along the way. Fit in a 64-by-33.5-inch box capable of sliding into the tunnel that houses a conventional car’s driveshaft. Weigh no more than 400 pounds. Cost as little as possible. And never, ever explode.
This is not an easy order to fill.
That’s because batteries are unruly pieces of technology. Each is a brew of billions of molecules that work together to store electrical energy as chemical energy. Ions (charged particles) swim back and forth between the positive and negative terminals through an electrolyte, a solution that acts as a bridge between the two terminals. During discharge, this process produces electricity by knocking electrons loose from the negative terminal. Those electrons then flow up a current collector, out of the battery and through an external circuit before traveling back down into the positive terminal, where they start the loop again. Problem is, those billions of molecules form an infinitely complex system in which all manner of chemical-reaction mischief can take place. And few battery technologies are more prone to mischief than the one that every single semifinalist was presenting to GM: lithium ion.
Lithium-ion batteries are far lighter and more energy-dense than the lead-acid and nickel-metal hydride that preceded them (and that powered the two generations of EV1 cars). They are the batteries behind the incredible shrinking of consumer electronics over the past decade. But when overheated, overcharged or otherwise abused, lithium-ion batteries — particularly those found in cellphones and laptops, which generally use some form of lithium cobalt oxide for the positive terminal, or cathode — have an unfortunate tendency to start a chain reaction that can end in what battery scientists call thermal runaway. Search for “exploding battery” on YouTube, and you’ll get the idea.
So before a carmaker can even consider using lithium ion in a mass-produced moving vehicle (every hybrid on the road today uses nickel-metal hydride), it needs to move beyond lithium cobalt oxide. Hence GM’s elaborate vendor-elimination process. Since Sony developed the first commercial lithium-ion battery in 1991, researchers have created dozens of variations on the technology, primarily by changing the makeup of the cathode. Sixteen years later, GM was on the hunt for substrains of lithium ion safe and powerful enough to put in the highest-profile car in the company’s 100-year history.
On June 5, 2007, at GM’s annual shareholder meeting, Bob Lutz, the vice chairman of global product development, announced the two finalists in the Chevy Volt battery race: Compact Power, Inc. (CPI), the auto-battery arm of the Korean consumer-electronics battery giant LG Chem; and A123 Systems, a Watertown, Massachusetts, start-up that would be partnering with the German auto-parts manufacturer Continental to package its cells into fully functional battery packs.
CPI had been working for five years on a cathode chemistry called lithium manganese oxide, which is cheaper and safer than lithium cobalt oxide and has one major advantage for automotive applications: excellent power. Think of a bottle of water. Energy is how much water fits in the bottle; power is how quickly you can pour it out. A lack of power isn’t a big deal for a laptop, but in a car, power equals acceleration.
Cobalt chemistries are low on power because they form two-dimensional structures that restrict the number of ways lithium ions can enter and exit the cathode, placing fundamental limits on how quickly the battery can discharge electricity. In contrast, CPI’s manganese-based cathode is a three-dimensional crystal lattice that makes it easy for lithium ions to come and go quickly. Faster exchange of ions means more electrons pumped out more quickly, which means more power.
But to mold this raw technology into a battery fit for the Volt would take much more work. “We had to have a cell that effectively doubled the energy capacity of a typical hybrid cell,” says Prabakhar Patil, the CEO of Compact Power. CPI’s 70 staffers worked late nights and weekends for four months after the shareholder meeting. They then surprised the engineers in GM’s battery lab by actually delivering their first finished battery pack right on time (somewhat ominously, on Halloween day).
Meanwhile, A123’s first pack was hung up in Customs. The U.S. Department of Transportation considers lithium-ion batteries hazardous material, which made it difficult to get the pack delivered from Continental’s packaging facilities in Germany. (It probably didn’t help that the stainless-steel casing wrapped around A123’s cells looked like a nuclear weapon from a Jerry Bruckheimer movie.) Appearances aside, though, A123’s lithium-iron-phosphate chemistry is probably the safest around. The covalent double bonds in the phosphate — the strongest chemical bonds in nature — make it nearly impossible for these cathodes to start the reactions that can lead to exploding batteries.
Finally, in January, Customs released the batteries, and GM learned that A123’s product would arrive any day. Jon Lauckner was in Washington, D.C., sitting on a panel on plug-in hybrids at the Center for American Progress, and he insisted he be told the very minute the battery reached the lab. Lauckner took the stage and began to field questions from the audience. “Where are you with the second battery?” someone asked. Lauckner looked down at his BlackBerry and replied, “It arrived in our lab five minutes ago.”
Generation Gap: The EV1’s monster lead-acid battery [left] next to the Volt’s lithium-ion pack
If you’re confused about why the pursuit of next-gen battery technology has suddenly reached Defcon 1 levels, you’re hardly alone. After all, we had a pure electric car — the EV1 — 12 years ago. How can it be so hard to build a hybrid version of the electric car now?
Lauckner took a stab at the question during his keynote address at an industry conference, Plug-In, this July in San Jose, California. Again he couldn’t seem to resist the compulsion to probe at the old wound. “Some folks have recently suggested that we just dust off the tooling — if we can still find it — and crank up production of the EV1,” he said. “And look: The technology of the EV1 was state-of-the-art 10 years ago. But GM has chosen to put our efforts behind newer and better technology that will have greater functionality and therefore a much greater chance of high-volume marketplace acceptance.”
That reasoning didn’t sit well with some in Lauckner’s audience of 700 or so insiders, agitators and true believers. Perhaps it would have gone over better if he had more directly stated his point, which was that the notion of reviving the EV1 is based on a faulty premise: that the electric cars of a decade ago were built on a viable battery platform.
“It was a different proposition for the EV1,” says Jon Bereisa, the chief of propulsion on the EV1 and an early instigator for the Chevy Volt. “The battery technology was not there and we knew it, but we believed that we could make up for it by designing a highly efficient car.” The EV1 got 65 to 95 miles per charge on a 1,000-pound lead-acid battery so large that a backseat was an impossible luxury. The second-generation EV1 extended its range to as much as 140 miles, but the large nickel-metal-hydride batteries that made it possible contained costly materials such as cobalt and vanadium, raising the price to as much as $40,000 or $50,000 a battery. Bereisa estimates that GM lost nearly $1 billion on the EV1 project. “We established technical feasibility,” he says. “You could say we nailed it. But we really did not achieve commercial viability.”
But technical feasibility and commercial viability cannot be mutually exclusive, which is one reason the bar for what an electric-car battery needs to accomplish keeps rising. It’s not enough for the Volt to get 40 miles (or more) per charge — it’s got to keep doing so for a decade, to satisfy both consumers and regulators. For GM to earn the coveted California Air Resources Board credits it needs, the Volt’s battery will have to carry a 10-year, 150,000-mile warranty.
Some battery-world insiders believe that this first batch of lithium-ion batteries has little chance of lasting that long. Industry analyst Menahem Anderman runs through the litany of complaints lodged against advanced automotive batteries. ” ‘The battery is too big, too expensive, and we are concerned about the life of the battery, the liability risk and the warranty’ — that’s what I hear at every car company I’ve gone to for the last nine years,” Anderman says. “And now I’m going to go to plug-in hybrids? The batteries are five times bigger, five times more expensive. The liability risk is five times more, or 10 times more.” Plug-ins brutalize batteries, he argues, by fully depleting them nearly every drive. As a result, General Motors must account for the possibility — or, as Anderman would say, the likelihood — that the expensive battery will die before the car itself.
Which is why the most nerve-jangling work of the entire Volt project is almost certainly the effort happening in a torture chamber in Warren, Michigan.
Battery Abuse: Two competing battery packs undergo longevity tests in GM’s battery lab.
Right now, probably even as you read these words, some very ugly cars are relentlessly circling an eyes-only test track in Milford, Michigan. These are the Mali-Volts — Chevy Malibus gutted and fitted with the Volt powertrain and covered with sensors and electrodes, like someone on a treadmill undergoing a cardiac stress test. Whether the Volt makes its November 2010 production deadline depends heavily on these cars. The Mali-Volts will show how the battery packs withstand the noise, vibration and harshness of being flogged on the track. Here, the final, crucial task of turning a collection of lab-developed parts into a marketable car has begun.
In early June, GM’s Lutz described his first Mali-Volt test drive to the eco-news Web site Greenfuelsforecast.com as both thrilling and eerie. “It’s like being in a conventional car at 70 miles an hour and coasting with no engine,” he said. The batteries were performing well, he reported. Some of the welds that tie the individual battery cells together had failed, but that was expected; the team was increasingly confident. “The guys are now convinced that unless we have some sudden whoops! that we don’t see, we’re good for November 2010,” he said.
If that “whoops!” does appear, it will most likely show up in longevity tests at GM’s Warren battery lab. There, those celebrated first two battery packs have for nearly a year been subjected to the abuses of the pack cycler, a refrigerator-size device that tests cycle life — how many times the battery can be discharged and charged again without deterioration. In two years on the cycler, engineers can put a battery through the equivalent of 150,000 real-world miles.
The other life-span-related variable, calendar life, is tougher to test. The only way to see how a battery ages over 10 years, really, is to make the battery, use it for 10 years, and see what happens. But if you have just two years — as GM does — the only option is to artificially accelerate the aging process by heating the batteries in a thermal chamber, a giant metal sauna where battery packs soak in a humid 185°F for months on end. At this rate, batteries from both A123 and CPI will have aged the equivalent of 10 years as of April 2010 — a scant seven months before the Volt is supposed to go into production.
It’s difficult to get specifics about how the batteries are holding up. Because of the Securities and Exchange Commission–mandated silent period that precedes its upcoming initial public offering, A123 declined to comment for this story. In July, Patil of CPI issued a vague declaration of confidence: “Today, a year after that initial award, we are marching right along the path without any showstoppers on the horizon.”
Specifics aside, that note of confidence is growing. At breakfast the day before his speech at the Plug-In conference, Lauckner smiled mischievously, clearly relishing the thought of proving the Volt’s many doubters wrong. All around him, the conversation was shifting from “if” to “when.” “The window’s closing on the skeptics,” he said. “And the only thing that’s going to be left at the end of the day is: Are we on time?”
The first architecturally correct Volt “mules” — the test cars that look and handle like the finished product — should hit the test tracks this month, right around the time the American electorate casts its vote between two presidential candidates who have both publicly endorsed the Volt and promised government incentives to help the car compete in the consumer marketplace.
But to reach the loftiest, longest-term goal — a large-scale shift toward an electron-based economy — batteries will someday need to beat oil on an even playing field, without help from government subsidies. They will need to be as powerful and cheap as the firmly entrenched fossil fuels they hope to replace. They will need to do a whole lot better, in other words, than the current target equation, which is, after all, still built around a 400-pound battery equaling a single gallon of gas.
“If somebody asked, ‘What should the ideal goal be?'” Lauckner says, “the ideal goal will be to have the same energy density as gasoline or diesel fuel. That’s where we’d say, OK, we’ve arrived.”