Elon Musk's SolarCity has been accused of intellectual property theft by Cogenra Solar and Khosla Ventures.
In a lawsuit filed in San Francisco on Monday, the parties accused SolarCity of gaining undue advantage of Cogenra's Shingling technology that helps in manufacturing high-efficiency commercially viable solar panels.
SolarCity and its subsidiary Silevo misappropriated Cogenra's trade secrets, manufacturing processes, and other intellectual property to give themselves a competitive advantage and head start in developing shingled-cell solar modules, Cogenra said in the lawsuit.
SolarCity said that last week it discovered that a former SolarCity employee had unlawfully downloaded confidential information, copied that information to a personal hard drive, and then joined SunPower as a senior sales manager.
"Any unauthorized copying and use of this information is a very serious violation of SolarCity's intellectual property rights so we immediately notified SunPower," SolarCity said in a statement.
Cogenra's complaint fails to identify any actual trade secret that Cogenra owns, much less that SolarCity supposedly misappropriated, SolarCity said.
From 2009 to 2015, venture capital firm Khosla Ventures owned about 80 percent of Cogenra, the lawsuit stated.
Last week Tesla said its proposed acquisition of SolarCity could be delayed because of shareholder lawsuits alleging board members breached their fiduciary duty.