tion when the first generation of production electric vehicles was introduced in the mid-1990s.
Released in 1996, the General Motors Co. EV1 lasted between 60 and 100 miles on a single charge.
Even the recently released Nissan Motor Co. Leaf has similar limitations, with an estimated battery range of just 100 miles.
Kurt Kelty, director of battery technology for Tesla Motors, said, “Our battery pack has 56 kilowatt-hours of energy. Other EVs on the market have about 20 or 24 kilowatt-hours.”
“The Roadster battery pack is over 120 watt-hours per kilogram,” he added. “That’s where our engineering strength comes in. We use a high energy density cell, and we pack it densely while also maintaining a high level of safety, reliability and long life.”
The emphasis at Tesla is to focus on what the company terms “energy density,” essentially a measure of the amount of energy stored per kilogram of battery mass. At its headquarters in Palo Alto, Tesla claims to maintain one of the most advanced battery development labs in the world.
Specifically, Tesla is developing technology that will allow consumers to easily replace used batteries with ones holding a full charge. The company plans to implement this innovation in the Model S sedan.
Despite the increased innovation in the field, driving down the cost of the batteries remains the greatest challenge.
Haresh Kamath, project manager in the energy utilization program area at the Palo Alto-based Electric Power Research Institute, said, “The main challenge with electric vehicle batteries today is their cost. It is a very large part of the difference in cost between an electric vehicle and a conventional internal-combustion vehicle.”
Tesla plans to release three different versions of the Model S sedan based mostly on battery life. The basic Model S with have a battery designed to run 160 miles on a single charge. It will cost $49,900 after a $7,500 federal tax credit.
The second battery option will have a 230-mile range, but will add about $10,000 to the price. The Model S with a 300-mile range should cost around $20,000 more than the basic version.
Ricketts, however, emphasized the importance of investment in battery technology. “Investing heavily in research and development, Tesla is proving that major breakthroughs are happening quickly,” she said.
Kamath said, “There are a number of manufacturers that are in the electric vehicle space, as well as in the electric vehicle battery space. While Chinese manufacturers are present, there are also Japanese, Korean, German and U.S. manufacturers that have competing battery technologies.”
“Lithium ion battery production is not very labor intensive,” Kamath added. “Competition is typically not driven by labor costs.”
Ricketts reports that new buyers are encouraged to charge their cars each evening using a standard power outlet in their garages. “Most of our Roadster owners find that they never even come close to depleting the battery. Charging is really just a matter of ‘topping up’ continuously,” she said.
Pohorsky said, “For the San Francisco Bay area, you can get from San Jose to San Francisco and back on one charge for a car that’s got a decent amount of battery in it. People need to sit down and really think about how much they normally drive in a single day, and that is surprisingly low.”
Concerns also persist over the impact that increased electric car usage will have on local energy grids. Kamath addressed this, saying, “While utilities do have to examine the effect of electric vehicle adoption on their distribution networks and may have to accelerate upgrades to their capacity in some places, at present, our analyses show that local power systems can accommodate the expansion of electric car adoption without much difficulty.”
He added, “The additional power drawn by electric vehicles is relatively small compared to the capacity of the grid, and a great deal of the charging is expected to occur at off-peak times, like the nighttime.”
A 2008 episode of the British television program "Top Gear" was particularly damaging to Tesla’s battery