Tesla CEO Elon Musk pointed out the Model S’ battery swap-ability was designed into the car back in 2009. The technology is the same as the one used during the manufacture process. Similar to Better Place’s now defunct system, drivers position their Model S over the replacement hole where sensors then detect and align. The automated system then removes the bolts holding the old 1,200 lb (544 kg) battery, sliding it down and out of the way and installing a new freshly charged battery. The whole thing took exactly 1 minute 33 seconds, which was less time than an Audi A4 took to fill its tank, at least according to Tesla's simultaneous demo.
Musk makes clear that owners “can have fast or you can have free,” meaning Model S owners can hit up the free Supercharger networks for some free juice or go with the battery swap for a fee. According to Forbes Model S owners will have the option to switch out the battery pack for roughly the price of 15 gallons (57 liters) of gas. For an anticipated fee of US$60–80, drivers can pick up their original (now recharged) battery on their return leg. Owners are billed via their credit card for the service without ever having to leave their cars.
Battery-swap stations will be installed next to existing Supercharger stations.
Source: Tesla Motors