The reason for Dhar's approach is simple: Improvements in power density and cycle life can be realized cost effectively. A small, 1.5-kWh lead-acid battery can adequately power a hybrid, while cutting costs by 50 percent, Dhar said. He ultimately hopes to be able to match the power density of nickel-metal hydride chemistries (which are used in 95 percent of hybrids) at one third their cost.
The company's concept doesn't end there, however. Dhar believes EPS can use its lead-acid technology in plug-in hybrids by teaming it with a small lithium-ion battery. In this scheme, the small lithium-ion battery would handle the energy (range) issues, while the lead-acid battery would provide the power. As an example, Dhar says he could replace the 16-kWh lithium-ion battery in the Chevy Volt with a 3.5-kWh lead-acid battery and a 9-kWh lithium-ion pack. Doing so, he believes EPS could cut the battery pack cost of a Chevy Volt from approximately $12,800 to under $6,000.
In essence, Dhar's concept boils down to a simple idea: At $100/kWh, lead-acid costs about one seventh of what today's liquid-cooled, lithium-ion battery packs cost. Moreover, lead-acid has been around for a century and is well understood by engineers.
EPS is reportedly working out a development plan with the state of Michigan and hopes to set up manufacturing facilities in an old Ford assembly plant in Wixom, Mich., by 2014.
With the auto industry scrambling to find a better battery for electric cars, Dhar believes the timing is right for his company's concept:
The industry discarded lead-acid chemistry a long time ago because it didn't have the energy density for electric vehicles. But we think it's time for a paradigm shift. We need to start thinking about how to improve miles per gallon by combining combustion with electrons. Once you do that, it lowers the amount of kilowatt-hours that you need.
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.
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.
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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