As we’ve previously reported Tesla plans to expand its range with a plug-in saloon in 2010. But now senior insiders have revealed that the new model’s underpinnings will be the basis for a whole new generation of all-electric cars. Known internally by its codename – the Model S – the Tesla saloon will be a sleek four-door capable of carrying five passengers and powered by an all-electric drivetrain. Company bosses say the new saloon is “ninety percent” designed and confirm it will be a standalone model separate from the Roadster, and built by Tesla from the ground up.The saloon will be launched in 2010 after Tesla finishes construction of a new factory in California. The company intends to sell up to 20,000 of its zero emissions family car a year, figures described by a senior manager as “extremely realistic”. Tesla’s relationship with Lotus, who build the Roadster’s chassis, won’t carry over to the Model S, which will be built on Tesla’s own unique platform. It will use lithium-ion batteries that can be recharged from any mains power source, and it should be able to hit 60mph from rest in under six-seconds using a seamless single-gear drive. Unlike the Lotus-based Tesla Roadster, which uses carbon fibre extensively to save weight, the purpose-built Model S will aluminium for its body and chassis. This factor, along with economies of scale, will make the Model S significantly cheaper than the £90k Roadster. Tesla’s early estimates put its price at around £35,000.>> Read our first drive of the Tesla Roadster
The whole structure of the Model S will be new from the ground up, with some components coming from unspecified major manufacturers. A part-sharing deal is likely to be brokered, with Tesla bosses claiming that "a number of" car makers have expressed interest in adopting the powertrain in their compact cars. Tesla has come up with a more compact lithium-ion battery pack design, which will be mounted flat on the base of the model S chassis floor. This clever powertrain packaging will allow for a number of larger spin-off models in the future - all based around the same Model S platform. Tesla intends to launch a large Mercedes CLS-style electric ‘coupe-saloon’ and an SUV by 2015.These big plans and a substantial investment programme have enticed leading motor industry figures to join the fledgling company. Tesla’s most recent signing is Franz von Holzhausen - the man responsible for the stunning Furai concept car. He’ll now lead the team that designs all of Tesla’s future products, along with adding the finishing touches to the Model S, and making improvements to the just-launched Roadster. Tesla will update the Roadster with a facelifted ‘Roadster 1.5’ in years to come and, incredibly, has plans to build a stripped out track version of its silent electric car to gain a presence in motorsport. The biggest challenge this ambitious company faces is with lithium-ion battery technology. Currently the batteries, which come from Japan, are very expensive to buy and to replace. Tesla concedes that the battery cells in the Roadster will only last at full-efficiency for around five years. But the Japanese companies that supply lithium-ion batteries promise that the costs will get lower and efficiency will improve as the technology matures.