Batteries are the biggest hurdle to get electric vehicles to market. Most automakers are already getting their packs through joint ventures with electronics companies, but there are also companies like Tesla that are manufacturing their own packs using off-the-shelf lithium ion cells. Tesla is also selling complete packs and other drivetrain hardware to interested parties. Among those might be Daimler, which is rumored to be using Tesla packs and motors in its second-gen smart fortwo ed. Daimler, though, doesn't rely on just the one supplier, as it uses nickel metal hydride packs from Cobasys in its two-mode hybrid SUVs and uses lithium ion packs from Continental in its mild hybrid models. Now, the German automaker has entered into an agreement with Evonik to create its own lithium ion units.