Tesla Inc. (TSLA) said Monday it will buy Maxwell Technologies Inc. (MXWL) , a battery technology firm based in San Diego, for around $218 million. Telsla will pay $4.75 for each Maxwell share, the company said, a 54.7% premium to its closing price Friday of $3.07, and bring the company into the corporate fold as a wholly owned subsidiary. "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 Maxwell CEO Franz Fink. "We believe this transaction...