Tesla Motors will continue to use its existing battery technology with the upcoming Model S. According to Kurt Kelty, the company’s director of battery technology, the Model S, which is aimed at a more mainstream consumer than the Roadster, will use the same types of small 18650 cells originally currently used in the Roadster. The company is evaluating other types of batteries like prismatic and pouch format batteries used by its competitors, but for now is happy with the performance delivered by its current suppliers. Kelty said the Japanese cell manufacturers offer the best quality with Korean companies catching up quickly. He said no Chinese cell manufacturers currently meet Tesla’s quality requirements.
Kelty said the price of lithium ion cells has been falling by about 8% per year, and he doesn’t expect that to change in the next few years. He said his battery pack manufacturing costs will drop significantly once they are moved from the current manual process of installing cells one by one, to a more automated process. The shift will be necessary to accommodate the company’s contracts to supply battery packs to the Smart EV and the upcoming electric Toyota RAV4.
New to the Model S will be an alignment of batteries that will enable them to be quickly swapped out. The layout of batteries underneath the rear of the vehicle is not compatible with Better Place’s current design for automated batter swapping, and Tesla has not explored designing its own robotics system for automated battery exchange.
The Model S will use Tesla’s proprietary fast AC charging equipment, with an adapter to plug into charging stations from companies such as Coulomb Technologies using the new J1772 standard available as a separate purchase. Tesla currently offers a $1500 universal adapter kit to enabling plugging into the many variants of 240V plugs available, or individual adapters for $100 each. The Model S will also have an optional adapter for DC fast charging as well.
The Model S will be sold with 3 battery pack size options: 160, 230, and 300 miles. Even the smallest of these options is more than enough to satisfy nearly all of most drivers’ trips. In most cases families with an EV will also have another car that will be used for the few long haul trips taken per year.
If driving the Model S is anything like driving the Roadster, it will likely be a hit with performance enthusiasts. While it’s a bit uncomfortable for those of us over 6 feet to climb into, driving the Roadster (as I did for 2 hours) is unlike any other car I’ve used. The urge to say “lift off” every time I pressed the accelerator with marginal force was strong. The Roadster holds the ground well and handles well on quick turns. The vehicle was designed with smarts so that you can coast without the regenerative braking slowing you down when you’re above 40 mph, but at slower speeds the braking brings you to a stop much more quickly than the other EVs I’ve tested. Being so low to the ground and the corresponding bumps in the road made driving highways speeds feel even faster than it is. Getting back into my rental mini-SUV left me feeling disappointing, save for no longer looking up to a Prius as if it were a giant vehicle.