Tesla Sues Cap-XX Over EV Battery Patents, Recalling Musk Pledge

Tesla Inc. sued a maker of energy-storage products that can charge and discharge much faster than batteries, alleging Cap-XX Ltd.’s supercapacitors infringe two patents—a move that calls into question Elon Musk’s pledge that Tesla wouldn’t litigate over its electric-vehicle inventions.

Musk, Tesla’s chief executive, drew global attention in June 2014 when he said in a blog post that “Tesla will not initiate patent lawsuits against anyone who, in good faith, wants to use our technology.” The post linked to a more detailed explanation of Tesla’s “patent pledge.”

The patents in the case—US Patent Nos. 8,591,601 and 8,279,580 ...