SAN FRANCISCO, Feb. 4 (Xinhua) -- U.S. top electric car maker Tesla Inc. will buy battery manufacturing firm Maxwell Technologies to boost its power storage technology, Maxwell said Monday.

Maxwell said it has entered into a definitive merger agreement on the acquisition by Tesla in an all-stock deal valued at 4.75 U.S. dollars per share.

The transaction, which is expected to be finalized in the second quarter of 2019, will cost about 218 million dollars.

Maxwell said its board of directors has unanimously approved the deal, although the transaction is subject to regulatory approval and customary closing conditions.

"We are very excited with today's announcement that Tesla has agreed to acquire Maxwell. Tesla is a well-respected and world-class innovator that shares a common goal of building a more sustainable future," said Franz Fink, Maxwell president and CEO.

The deal came amid Tesla's efforts to ramp up the production of its Model 3 sedan to make it affordable for more customers at a lower price. The company said last month that the better-than-expected sales of Model 3 made the car the best-selling premium vehicle in the United States for 2018.