Lithium-ion car battery maker A123 Systems Inc shares soared as much as 41 percent in their debut on Thursday in an eagerly anticipated initial public offering.

A123 started trading at $17 on Nasdaq following the company's IPO on Wednesday, when the stock price came in higher than anticipated and more shares than expected were sold.

The company sold 28.1 million shares for $13.50 each in the IPO. The upsized deal helped it raise $380.4 million.

If A123 holds onto its gains, it would rank among the IPOs this year with the greatest first-day pops.

A123, which was founded by scientists linked to the Massachusetts Institute of Technology, develops batteries and battery systems for hybrid electric vehicles, plug-in hybrid electric vehicles, and electric vehicles and works with such carmakers as BMW, Chrysler and General Motors Co GM.UL.

(Reporting by Phil Wahba; Editing by Lisa Von Ahn)