Electric carmaker Tesla Motors will serve as a key supplier to Toyota Motor Corp under its agreement with the Japanese automaker to build an electric Rav4 SUV, Tesla Chief Executive Elon Musk said on Thursday.

Musk, whose company was listed in June, said there was a good chance the first thousand electric Rav4s would be built at the former Toyota Motor Corp and General Motors joint-venture plant Tesla is acquiring in Northern California.

After that, production would have to move from the New United Motor Manufacturing Inc (NUMMI) plant if demand rises to the tens of thousands of vehicles, Musk told Reuters in an interview on the sidelines of the Paris Auto Show that disclosed some key details of the Tesla-Toyota tie-up.

We're a supplier, but a tightly integrated supplier and it is a co-development, so Toyota engineering and Tesla engineering are working very closely together, Musk said.

Musk said Tesla engineers were responsible for the powertrain in the Rav4 electric, which includes the battery, motor, inverter, charger, transmission and software. Toyota will do vehicle modifications and final validation, he said.

Long term, I think our relationship with Toyota is a function of how good of a supplier we are, Musk said.

Tesla, best known for a $109,000 electric Roadster, is in the pre-production and planning stages to produce a sedan called the Model S that would cost about $57,400. It posted a net loss of $38.5 million in the second quarter.

Musk said that Tesla has sufficient capital to bring the Model S to production with delivery to customers starting in mid-2012. He envisions a family of vehicles on the same platform starting at the end of 2013.

We have about 50 percent more capital than we need to bring the Model S to market, Musk said.

That capital includes $400 million from a U.S. Department of Energy loan and a couple of hundred million dollars of cash, Musk said.

I feel very confident that we have enough capital to complete the Model S at present, even assuming cost overruns.

Tesla has about 50 former NUMMI plant workers on staff now and could have several hundred people working at the plant when production starts on the Model S sedan, about 10 times less than worked there at the height of GM and Toyota production.

He said that within five or six years, Tesla would hope to be at 5,000 workers, the same as used to be there, but would need to get a third vehicle platform up and running to use the substantial capacity of NUMMI.

(Editing by Michael Shields)