Not Battery Fast Charge, Battery Switch

While others are working to introduce battery fast-charging methods to electric vehicles, Better Place has developed a different method of 'recharge'.

"Catalyze the transition to widespread electric vehicle use."

That's been Shai Agassi's mission since founding Better Place (, a California-based electric vehicle (EV) services provider, in 2007. In order to achieve that goal, Agassi says EVs must first be able "to do anything and go anywhere" with the same convenience of gasoline-powered vehicles. But considering today's limited battery ranges of 35 to 100 miles, high costs, and the lack of a convenient, gas-station-style fast recharging method, there are technical and infrastructure issues that need to be addressed.

It should be noted that the average motorist drives about 35 miles each day, which is within battery limits of emerging EVs like the Chevy Volt and Nissan Leaf. The prevailing notion is that the driver would come home from work in the evening, then plug in for an overnight recharge. But then there are those people who need to travel more than what a single battery charge permits. As a means of offering a faster recharging method than the standard four- to eight-hour long "trickle charge," some companies have introduced 30-minute fast charging solutions. But Agassi notes that's far longer than a typical refuel at any gas station and so is not exactly a technology that's going to enable EVs to "do anything" to the extent a combustion engine vehicle can.

Better Place has developed its own method of fast battery recharge—a method that actually doesn't have to do with battery charging at all. Instead, it's about battery switching. Better Place debuted the world's first commercially operational battery switch station on April 26, 2010 in Tokyo. It is something like one of those quick oil change setups, where you drive in and the worker does work below your car. Here the driver has a depleted battery taken from underneath an EV and replaced with a fully charged one, without requiring the driver to exit the vehicle. The process takes 59 seconds. In the Tokyo station setup, three specially converted Nihon Kutsi switchable EV taxi cabs used the station over a 90-day demonstration period in a study with the Japanese Ministry of Economy, Trade and Industry.

The cabs' 17-kWh lithium ion batteries (developed by A123 Systems; provide a range of about 100 miles, which required use of the switch station three times a day. Why demonstrate with taxis? First, because taxi drivers don't have time for 30-minute, four- or eight-hour breaks to recharge, and secondly, because the tough driving patterns of cabs adequately test the durability of the switching infrastructure. (It should also be noted that Tokyo has 60,000 taxis—more than New York City, London and Paris combined—which contribute to 20% of the city's annual vehicle emissions, so you can only imagine how much cleaner the city would be if every taxi was electric.)

"At some point, we've got to prove the charging works," Agassi says. "At some point, we've got to prove the switching works. Then we have to put cars on the road and show they actually switch."


Why Battery Switch?

"The thought of a battery that will do 300 miles and then go to a gas station or a battery station and charge up in five minutes—that's just unrealistic," Agassi says.

It's unrealistic because, as Better Place Director of Energy Storage Technologies Michal Vakrat Wolkin puts it, a 300-mile range battery would likely cost over $25,000, in terms of a high volume production estimate.

Then there's the idea of a five-minute rapid charge. Wolkin says although seemingly possible, the 300 kW of power required to recharge a 24-kWh battery is about half of what is required to power an average office building. Just think of the impact on the power grid if every driver were to do that. Additionally, the high charging temperature would be detrimental to battery lifecycles, so much that Wolkin says rapid charging would decrease the lifespan of a battery from about 2,000 cycles to only hundreds.

Although 17-kWh batteries were used in the Tokyo taxi demo, Better Place is primarily working with purpose-built 24-kWh lithium ion batteries, which provide enough power to drive a standard sedan for a little more than 100 miles. These flat "pancake batteries" are located underneath the vehicle, held in place by a high-strength latching mechanism that not only gives the EV a better center of gravity, but allows for easy removal and attachment at the switch station. High production estimates tab these 24-kWh batteries at around $12,000, Wolkin says. Still expensive, yes, but since drivers won't necessarily "own" these batteries in switchable EVs, those high upfront costs are minimized.

The first switch station debuted in Yokohama in May 2009 after two years of research and development, and simply proved that battery switch was viable. The Tokyo switch station accelerated the switching process and proved that battery switch is durable and effective. "We're the first ones that have actual cars on the ground that prove it can be done," Agassi says. "We've got a solution that actually works." And at a rate that's much faster than fast charge.


The Better Place Plan

The switch station is just one piece of an overall solution that Better Place has planned for widespread EV adoption. By the end of 2011 plans call for Renault EVs in Israel and Denmark that will be networked with switch stations and tactically placed public charging spots (e.g. shopping malls, business districts and sports arenas where you can trickle charge your vehicle for hours at a time as its parked). In-car networks will direct drivers to local charging or switching locations. Agassi says 1,000 switchable EVs will be imported into each country per month following commercial launch. Better Place is also working on developing EV technology in China, Australia, Canada, France, and parts of the United States.

"The industry has not yet realized that if you actually have a product that has a network to support it that gets around the fear of consumers, high percentages of consumers will go and pick that car up," Agassi says. "The last transformation of this magnitude was called the Ford Model T."