Could Hybrids Use Lead-Acid Batteries? Startup Says Yes

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1914 Detroit Electric car, Schenectady, NY, June 2011 - original lead-acid batteries

1914 Detroit Electric car, Schenectady, NY, June 2011 - original lead-acid batteries

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It's quite easy to forget that cars have been using batteries for years before hybrids and electric vehicles arrived.

The humble lead-acid battery, the planet's most recycled product, has been starting engines and providing power for car electrics ever since such a thing was required.

Now, battery startup Energy Power Systems (EPS), fronted by battery guru Subhash Dhar, has designed a new lead-acid battery which could replace the nickel-metal hydride and lithium-ion units in hybrids.

Using familiar chemistry but a new internal structure, Dhar says his batteries have the same power flow as NiMH batteries, but cost significantly less.

As Wards Auto reports, Dhar's history is impressive. He previously led development of the Ni-Mh batteries now used widely in hybrid applications, and his previous company also supplied now-bankrupt electric carmaker Think.

His idea comes as electric car sales remain low, but electrification in mild hybrid, full hybrid and plug-in hybrid vehicles is increasing.

Dhar believes that costs have to come down in order for hybrids to be accepted widely, and inexpensive lead-acid technology could be the perfect way to do this. Lead currently costs $1.80 per kilogram--cobalt is currently at $44/kg, and nickel at $11/kg.

Low costs and an improved structure make Energy Power Systems' batteries a tempting proposition.

Where normal lead-acid, 12V car batteries feature six blocks of 2V cells, the new battery features a more direct energy path with interlocking cells. Electrical resistance and weight are both reduced.

The net result is a power rating of 1,900 W/kg--four times that of current lead-acid batteries, and greater even than that of NiMH, at 1,450 W/kg. Better still is the cost--$15-20 per kilowatt, compared to $40-60 for nickel and lithium.

Dhar also says that in a typical hybrid application like the Prius, the batteries would take up less space as they require less thermal management and electronics.

EPS is just one of several other battery makers reconsidering lead-acid, though Dhar thinks his design is the simplest.

Current prototypes have been built by hand, but the company expects to have automation soon and production is expected in the fourth quarter 2014. The aim is to supply the light vehicle market by 2016.

Dhar says he isn't worried that automakers are still continuing down the lithium and nickel paths with small hybrid batteries.

"They have no option - until they find out what we are doing."


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Comments (7)
  1. The problem with Lead Acid battery has always been weight or energy density. It typically uses 40% of its energy stored to power itself in transportation of its own weight. That doesn't leave much to power the rest of the car.

  2. I believe you are spot on with your estimation. I have a GEM nev that weighs 1200 lbs with batteries and they weigh half of that weight. I have extensively modified my GEM to go 40 mph and still gets an equivalent of 350 mpg at (1 cent per mile). It is still cheap to drive even with all the battery weight. In addition the motor and trans axle only weight about 70 lbs. so if this were a gas car of the same dimensions I wonder what the whole drive train, cooling system, fuel storage etc. would weigh.

  3. the three metrics for electric cars and hybrids is Watts/KG, Joules/KG and $/KG or Joule.

    i suspect there is lots of room to improve Lead battery performance and for low power hybrids where the motor is purely an assist, this may well solve a niche.

  4. 2 questions:

    whats the cycle life?

    where can i buy one?

  5. Ditto on cycle life as going to nimh or lithium are major jumps up in that area.

    Also, if you're putting lead acid batteries in hybrids, you want your batteries to be partially charged while driving so there is room to capture energy via regenerative braking. But, lead acid batteries do not like being partially charged because they suffer from sulfation which reduces capacity.

  6. This looks like all hype and no substance. Not a word about energy density, only power density. Energy density and price is what counts, power density is quite adequate in NiMH and Li-Ion and having higher power density is a moot point. And what the heck is "interlocking cells" supposed to mean? Certainly doesn't offer any clue why this should be better to me.

    Not all lithium-ion batteries use expensive cobalt. The Chev Volt and Nissan Leaf for instance, uses much cheaper manganese.

    And why did the Think fail? Because of over-priced batteries. I certainly wouldn't want to put that on my resume.

  7. Unless there's some magic to this other than what's reflected in the article, this is just another stopgap. Incremental improvements won't yield a solution. Think an order of magnitude in capacity.

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