Mercedes-Benz's parent Daimler AG, which counts Geely as one of its biggest shareholders, has been betting on China's young, city-dwelling consumers to rejuvenate the brand in the world's largest auto market. The Smart joint venture will have to compete with a multitude of established and up-and-coming electric-vehicle makers in China. Following the spinoff of Daimler's truck unit in December, the German carmaker is changing its name to Mercedes-Benz Group AG on Tuesday, to signal its segue to a nimble standalone unit tackling the industry's transformation.