Electric Cars and Batteries

The basic problem with electric cars is that the batteries are too big and take too long to charge. The Tesla Roadster motor is 70 lbs, has one moving part and is the size of a watermellon, yet it gives high-end sports car performance using a one speed transmission! The battery, however, weighs 1000 lbs. To say the least, that's a bit more than a full gas tank on an internal combustion car. The Roadster also takes about three hours to charge. That makes for a long pit stop. The Tesla Model S will improve on the charging time, getting it down to 45 minutes.

Clearly, if we had a battery that could charge in 5 minutes and was near the weight of a full gas tank, electric cars would be awesome. Even several hundred pound batteries with appropriate range and power output would be an improvement.

I have reason to hope that batteries will improve significantly in the next several years. I list my reasons below. They are basically taken from Wikipedia's article on lithium ion batteries, but I have read about many of them elsewhere.

• The big problem with Li-ion batteries is that they have a high internal resistance, mostly due to electrode (anode and cathode) materials. This causes heat and energy loss. Tesla had to specifically design a cooling system for their Roadster battery pack to keep it safe. There are several proposals to address this problem.
• In April 2006 researchers at MIT announced they could grow micro wires with viruses. This technology would improve Li-ion energy density by a factor of three (e.g the 1000 lb Roadster battery would only weigh 333 lbs). In April 2009 New Scientist reported that the MIT team succeeded in making a battery with their virus technology.
• In June 2006 researchers in France produced nano-structured electrodes with several times the energy capacity of normal electrodes.
• In September 2007 the University of Waterloo, Canada, developed a new cathode chemistry using fluorine. It would increase battery life and allow replacing lithium with cheaper and more stable sodium.
• In November 2007 Subaru unveiled their G4e concept electric car with Li-ion batteries that have double the energy density of normal Li-ion batteries. In the lab the Subaru-type batteries have been shown to have three times the energy density of normal Li-ion batteries.
• In December 2007 researchers at Stanford created a Li-ion battery with nanowires that had ten times the energy density of normal Li-ion batteries. They hope to commercialize their technology in five years. (If they could achieve this, the Roadster battery would only weigh 100 lbs!)

If some or all of these hit in the next few years, even in a decade or so, batteries will improve enough to make electric cars superior to gasoline cars. Plus our electric toys -- cell phones, computers, et al -- will get much better as well. I'm excited!