Using a souped-up version of a chemistry that's been around since the days of Edison, a Detroit-area startup wants to slash the costs of batteries for hybrids and plug-in cars.
Energy Power Systems (EPS) says it has boosted the power density and cycle life of the venerable lead-acid battery, without touching the low costs that made it desirable in the first place. With the new technology, batteries for mild hybrids and plug-in cars could cost less than half of what they do today, the company says.
Subhash Dhar, chairman, CEO, and founder of EPS, said in an interview:
The concept has always been to start with a chemistry that gives you high energy density, and then hope you can reduce the cost. But the industry has never made much progress in terms of cost. So we turned it upside down -- we started with low cost and improved the technology, so we can get the performance without disturbing the cost structure.
Energy Power Systems (EPS) proposes replacement of a 16-kWh lithium-ion battery, like the one in the Chevy Volt, with a 9-kWh lithium pack and a high-power, 3.5-kWh lead-acid pack. (Source: EPS)
In truth, the energy numbers of EPS' batteries are puny compared to that of today's lithium-ion batteries. Whereas, lithium-ion typically checks in around 150 Wh/kg, the EPS battery is 40 Wh/kg. But that doesn't worry Dhar. The EPS battery is not targeted at high energy (which translates to driving range in an EV), but is instead focused on power density. Power density is far more important for full hybrids, mild hybrids, and micro-hybrids, since those vehicles can extend their range by burning gasoline, Dhar told us. "When you realize that energy isn't critical, and power is critical, you can boost the power and not worry about disturbing the fundamental low-cost structure of lead-acid," he said.
That's why his company has lifted the power density of lead-acid from about 200 W/kg to 1,600 W/kg. Cycle life has similarly been improved by a factor of five.
I never thought I would hear about lead-acid batteries again. Traditionally, the chemistry isn't very finicky, but the cycle life is poor and the energy density is terrible. One bright spot in the chemistry is that the cells are easily recycled, with something like 97% of depleted cells being recycled.
Now this is a good engineering story. As we have debated hybrids and EVs, the issue has always been cost. The answer to the battery issue has always been lithium ion. This is not a technology I would embrace because of the cost.
By approaching the problem of cost rather than starting with a technology to apply, the EPS is solving the problem. I also like the hybrid lead acid and lithium ion idea. It is similar to a concept used in disk drives where a small solid state device is paired with a spinning drive to provide both speed and large storage at a lower cost.
Considering the announcement today that the Volt is losing $49K per car I have to wonder if the $12k for a battery pack is any closer to reality than the $40k retail price.
Mixing battery technologies seems to have the potential to reduce costs without hurting overall performance. Aren't marine deep-cycle batteries lead-acid ? The lead-acid seems like the answer to acceleration, while the lithium-ion is there for range.
That statistic that Volt is losing $49K per car is quite shocking, Dennis. Obviously, that can't be sustained no matter how high government subsidies may be.
I suspect that the $40k retail price was chosen as the price they could eventually reach if development and volume go as per plan. Considering that the public has been reticent with $7500 off that number I think this will be a problem.
I agree, Dennis. This doesn't look promising unless that are some technical breakthroughs to lower the cost of building the Volt. It doesn't look like high-volume consumer purchasing is going to save the day.
Lead acid batteries have been around more than a century and even in high volume applications like SLI they still haven't been supplanted by alternative chemistries. These high performance batteries just don't scale and in the case of Lithium vs oil, all you're doing is trading the source of natural resources from one non-US friendly country to another.
Most people don't need 0-60mph in 4 seconds and 300 miles on a single charge, especially if the vehicle ends up costing more than their home. Build an EV or hybrid that competes with ICE in terms of cost per mile and TCO and you'll have a winner, irrespective of the source of electrons. Most people don't care if their cars run on gasoline, electric or the squeezings from baby seals - they just want a car that gets them from A to B in the most affordable way. EV's or any other alternative fuel will not succeed unless it's artificially mandated through law or solves an economic problem.
Ford is probably on the right track with their multi-drivetrain Focus. Remains to be seen if they can get the price point where it needs to be.
This was a great article. It is exactly the type of thinking thats needed to draw hybrids away from the fringes and make them a reality for a broader range of vehicles. It's refreshing to see that someone has finally decided to drop the costly idealism associated with so many of these alternative technologies and is moving forward with technology that makes more sense economically.
Good points, Contrarian. The drop off in sales of EVs, and the reluctance of hybrid owners to buy a second hybrid shows this market is presently very limited. It seems to me these vehicles are mostly for those who are interested in preserving the environment and have a few extra bucks to overspend on a second car. The price of gas isn't going to go high enough to justify the investment in an expensive gas saver. Hybrids and EVs will likely remain a small specialty market until technical breakthroughs change the present scenario.
Tesla Motors plans to roll out a “compelling, affordable electric car” that will sell for about half the price of its high-profile Model S by the end of 2016, company chairman Elon Musk said last week.
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