Battery Pioneer: Lead-Acid Is Key to Reducing Electric Car Battery Cost
Does Subhash Dhar know what he’s talking about when he says he knows the way forward with electric car batteries? Is he on to something when he says his company, Energy Power Systems (EPS), can make storage systems for battery EVs at a quarter their current cost?
Dhar’s breakthrough is not in building a better lithium-ion battery, in fact his solution doesn't use lithium at all. Instead, EPS is going back to basics with the technology that electric cars started out with at the beginning of the 20th century—lead-acid. Dhar says the company is adopting the lessons used in li-ion to vastly improve the efficiency of lead-acid.
There are good reasons to be skeptical about this, because EVs powered by lead-acid today are mostly short-range, low-power neighborhood vehicles. Lead-acid technology hasn't really improved all that much since the Detroit Electric was on the road in 1915.
But Dhar isn't saying that lead-acid alone will be viable in electric cars. Instead, he wants to combine the high energy density of li-ion with the power delivery of lead-acid—two battery types working together in one cost-effective pack. Again, he promises the same performance at considerably less cost. At $800 per kilowatt hour (an upper end estimate), a 30-kWh battery becomes a $15,000 cost to the manufacturer, which explains why you’re not getting into a LEAF for less than $30,000 (without government incentives).
Dhar's argument is based on the continued high cost of lithium-ion. “Look,” Dhar says. “the U.S. Advanced Battery Consortium (USABC) was formed in 1991, and its early grants helped ECD-Ovonics to commercialize nickel-metal-hydride technology. ABCD's aim was to get lithium-ion down to $150 per kilowatt-hour, and it was supposed to have been achieved by 1998. The energy density has improved, but we are still hard-pressed to find li-ion batteries today that are any less than $800 per kilowatt-hour. The fundamental problem is that the industry always goes for the glamor of watt-hours per kilogram, with not nearly as much attention paid to the cost of materials used in the technology.”
If Dhar is exaggerating the cost of lithium ion batteries to make his point, it's not by much. Leaders in the field, including Ford, Nissan, Pike Research, and Advanced Automotive Batteries all pinpoint the cost of finished installed EV battery packs between about $650 and $750 per kilowatt hour. Furthermore, these costs are expected to fall by about 10-percent every year for the next few years.
Dhar believes he can reduce costs further and faster by using the most venerable battery tech in the world, in cars before the 20th century dawned. “Lead is the cheapest material, and we’ve been using it in batteries for 165 years,” Dhar said. “But we haven’t made all that many improvements to it. So our thinking at EPS was to think out of the box and apply new learnings to old technology.” Read a three-part interview with Dhar to see if you find his arguments convincing.
I can’t prove that Dhar holds the magic formula, but he's worth listening to because of the man’s considerable experience in the field, as founding president at ECD-Ovonics (where he helped the legendary Stan Ovshinsky develop and market the now-standard nickel-metal-hydride battery), as president of Volvo supplier Ener1, and as chairman and CEO of Envia Systems—the company with the serious backing of the federal ARPA-E agency that says it is going to change the world.
It also bolsters Dhar's case that EPS’ board includes both Ken Baker, a pioneer who led the EV1 team at General Motors, and David Cole, one of the best-known auto industry interpreters and founder of the Center for Automotive Research (CAR).
Cole told me, "The key things are that the EPS battery will be about twice as energy dense as current lead/acid batteries. The company's batteries have low internal resistance, which makes them far better for taking power out and adding it back in than with lithium batteries. I think it is a great compliment to current technology."
EPS is confident enough about its technology that the Troy, Michigan-based company is talking about taking over a portion of Ford's Wixom, Mich. assembly plant, shuttered in 2007, to make its batteries. But so far the fledgling company lacks a website.
Increasing the Power
Dhar claims his company can delivery lead-acid batteries with greatly increased power without adding any cost back in or any tradeoff in energy density. Durability is also maintained, he said. The immediate market for these vastly cheaper batteries will be competing with companies like Johnson Controls to supply lead-acid batteries for micro-hybrids (storing the energy needed to power stop-start systems), full hybrids like the Prius, and mild hybrids such as the eAssist Buick LaCrosse.
The EV batteries will come later, Dhar says. He envisions cheaper battery solutions that combine the best of both worlds—high power from lead-acid and limited power but high energy density from li-ion.
The advanced lead-acid concept has moved beyond the planning stages, with engineering prototypes now under development. “Let’s start with a very low-cost material,” Dhar said. “As the Stan Ovshinsky used to say, you can’t fall out of bed if you’re already lying on the floor. Lead-acid can’t store as much energy as li-ion, but we’ve developed it to the point where it can deliver the power need by the LaCrosse and Prius.” OK, but as Dhar says of Envia, he has to prove his contentions. Neither company has yet shown off engineering mules with their batteries installed.
The bottom line, of course, is that if the li-ion battery stubbornly resists cost improvements, solutions like EPS’ will have to be considered. But li-ion companies, such as Dhar's former company, Envia Systems, aren't standing still. Envia says it's on the cusp of $20,000/300-mile EVs. If that happens, then EPS will be the patent holder on one more EV solution that never got out of the starting gate.
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