ford fusion times square mulally seacrest

As American automakers prepare for stricter, federally-mandated fuel efficiency standards, anything that can take a car farther on a gallon of gas is welcome news.

That's partly why start-stop technology, which saves fuel by shutting down the engine when the car stops for more than a few seconds (like at a red light), is finally picking up in the United States.

Start-stop has its problems, but a new way of making batteries could make the technology a lot more viable.

The Problems With Start-Stop

Last year, AAA predicted that 8 million cars in North America would be equipped with start-stop by 2017. That's not a huge number: Americans bought 7.2 million new passenger cars and trucks in 2012 alone. The technology is more common in Europe and Japan, where it's included in some 40% of new cars, AAA says.

While there's no doubt it saves fuel — by as much as 12% — start-stop is not good for battery life. Things like air conditioning and the radio are powered by the engine, and if it turns off at red lights, the battery has to pick up the slack — that's why the battery dies if you leave your headlights on when your car is off.

The "key limiter" of start-stop technology "has always been the performance of the battery and the cost," said Chad Lewis, Chief Global Strategy Officer of Texas-based Molecular Rebar Design (MRD), a maker of carbon nanotube technology that can be applied in cars.

In February, Panasonic released a battery system that powers the car's electronic components with energy generated by braking, which is recovered and stored in a nickel metal hydride battery that's separate from the lead acid battery under the hood.

But MRD says it has found a solution that goes to the root of the problem, by making the lead acid battery itself better. The company has published a patent for a technology, which it says will dramatically improve battery life for a variety of applications, starting with acid lead batteries.

A New Solution

carbon nanotubesThe breakthrough is a new way of using carbon nanotubes, microscopic cylinders of carbon molecules that are both extremely strong and conduct electricity. They have a lot of potential that "wasn't able to be unlocked," Lewis said, because they form in convoluted bundles (see photo at left).

Lewis compared those bundles to cotton balls, which are no good for making clothing. But in 2010, the company found a way to make them discrete — untangle them into individual pieces of thread — and much more useful.

The result is nanotube wiring that "functions just like rebar," the reinforcing steel used to make concrete stronger. 

MRD found that adding individual nanotube wires to a paste used in the production of lead acid batteries improved ion transport within the battery, making it last 50% to 70% longer, allowing it to hold a larger charge, and cutting charge time in half.

The resulting battery can also be used in addition to advances like Panasonic's system, to provide even greater advantages.

The lead acid battery manufacturing process, conducted by MRD subsidiary MRLead LLC, is already underway at some offshore facilities and should start in the U.S. in the next few months on a large-scale basis. Batteries with the technology come with a 15% to 20% markup in price, but the huge benefits in how they can be used make them a no-brainer, Lewis said.

The Best Is Yet To Come

The immediate benefits will be for lead acid batteries, and could make start-stop technology more viable. But, Lewis said, this is a "core technology that is applicable in any battery space."

That sets up MRD for its next, much more significant challenge in the auto industry: revolutionizing the lithium-ion batteries that are the most serious obstacle keeping electric cars down.