Tesla motors aren't the only ones willing to share its patents with rivals in order to help the sales of EVs pick up. BMW said it is open to sharing its EV battery cell technology it co-developed with Korea's Samsung SDI.

BMW purchasing boss Klaus Draeger said, “If Mercedes called us, we would be happy to find a way with Samsung SDI to supply them with battery cells.”

BMW sold 5,396 i3 electric vehicles globally in the first six months of the year out of a total of 1.02 million vehicles it sold during the period.