Tesla plans to expand in Japan to at least 60 stores as it seeks to become the country's biggest imported car brand by as early as next year, the head of its Japan business said on Friday. Expanded store and service centre coverage and investment in training over the past two years have helped drive Tesla's sales growth in Japan, said country manager Richi Hashimoto, even as electric-vehicle adoption in the country remains modest. The Elon Musk-led company's expansion in Japan comes as battery-powered car sales have slowed heavily in the U.S. and other key markets globally, increasing the importance of regions where electric vehicle penetration remains low.