on october 10, 2000, texaco announced the purchase of gm's share in gm ovonics, and chevron announced its acquisition of texaco six days later. in 2003, texaco ovonics battery systems was restructured into cobasys, a 50/50 joint venture between chevron and energy conversion devices (ecd) ovonics. chevron's influence over cobasys extended beyond a strict 50/50 joint venture, holding a 19.99% interest in ecd ovonics. in addition, chevron maintained the right to seize all of cobasys' intellectual property rights in the event that ecd ovonics did not fulfill its contractual obligations. on september 10, 2007, chevron filed a legal claim that ecd ovonics had not fulfilled its obligations. ecd ovonics disputed this claim. since that time, the arbitration hearings were repeatedly suspended while the parties negotiated with an unknown prospective buyer. no agreement was reached with the potential buyer. cobasys's patents relating to nimh batteries expired in 2015.