Battery researcher Don Murphy once thought of lithium batteries as an interim step on the way to more energy intensive hydrogen fuel cells.
But the former Bell Labs director and expert on lithium-ion batteries knows better now. Fuel cells, which he expected would be the state of the energy-storage art today, still don’t work the way they should.
The energy density of a lithium ion battery could improve 2 to 3 times, says prominent researcher Don Murphy, but it is hard to predict when.
And lithium-ion batteries – the fuel source for a highly anticipated first generation of electric cars – are dawdling as well, remaining far less capable than some might have hoped.
Battery technology improves at the paltry rate of 7 percent or less a year, Murphy said Thursday, compared with the 35 percent advance typical with high-tech electronics. “Don’t hold your breath looking for improvements,” he said during an afternoon address at the Parc Forum in Silicon Valley.
At that pace, capacity will double in roughly 10 years, and the battery will remain a restraint on electric cars during the formative years of the industry.
Electric cars are envisioned as a key piece of the world’s response to global warming. But range limitations – 40 miles for the Chevy Volt, 100 miles for the Nissan Leaf – will likely keep many mainstream buyers away. To catch on, these relatively simple-to-build vehicles need to duplicate the long-trip ease of gasoline-powered cars. Until they recharge faster and hold a charge longer, they probably won’t become suburban necessities.
Holding back progress are limitations with the lithium ion chemistry. Murphy projects that the energy density of a lithium ion battery has the potential to increase two or three times as technical breakthroughs occur. But he can’t predict when the advances will take place.
This kind of an improvement would help. But it hardly matches the doubling of performance that take place in an Intel chip every two years.
He says that today a lithium ion battery with a 100-mile range is as large as a big gas tank. A much larger battery, such as the one in a Tesla, with a 300 miles range costs $43,500.
That makes the electric car battery an expensive proposition and a lasting limitation on a young industry.
Posted by Mark Boslet 
The all-electric luxury sedan – comparable to a BMW 3-series or a Mercedes C-class – will cost half the price of Tesla’s sporty Roadster, at around $50,000 (after a federal tax credit) when it goes on sale in 2 years; allowing time for more rigorous testing before it actually hits the road.
