In a sign that a funding window may be opening for green tech companies, Boston based battery specialist A123 Systems has filed plans to raise $175 million in an Initial Public Offering. The company develops and manufactures lithium-ion batteries and battery systems for the transportation, electric grid services and portable power markets.

A123 was founded in 2001 and is headquartered in Massachusetts. It has patented Nanophosphate^TM technology which includes nanoscale materials initially developed at and exclusively licensed from the Massachusetts Institute of Technology.

The proposed IPO will be led by Morgan Stanley, Goldman Sachs and Merrill Lynch.  Pierce, Fenner & Smith Incorporated will serve as co-lead manager, and Broadpoint Capital, Inc. and Lazard Capital Markets LLC will serve as co-managers.