Tesla Motors Inc. shares are doing well Thursday after Panasonic Corp., which makes rechargeable batteries among its many products, bought a $30-million stake in the electric car company.

Panasonic, based in Osaka, Japan, paid $21.15 a share Wednesday in a private placement, Palo Alto-based Tesla said in a statement. Panasonic now holds about a 2% stake in the company. In afternoon trading in New York, Tesla shares jumped 13%, or $2.83, to $24.60.

Last week, Tesla opened the doors to its Fremont, Calif., factory, where it will build its $57,400 Model S sedan and future vehicles. The auto assembly facility had closed its doors in April, right before Tesla bought it in May.

The start-up also makes the $109,000 electric Roadster. The company has a partnership to develop next-generation lithium ion batteries with Panasonic and currently uses Panasonic technology for advanced battery packs in the Roadster.

The Japanese electronics giant joins investors including Daimler and Toyota, which fed $50 million into Tesla earlier this year. The start-up's much-anticipated initial public offering in June pushed its stock up 40% in the first day.

-- Tiffany Hsu

Photo: Tesla Model S electric car in 2009. Credit: Bob Chamberlin /Los Angeles Times