Chinese carmakers are gaining ground in Germany, Europe’s biggest car market. But Nio, the Chinese brand known for its battery-swapping system and premium electric-vehicle image, has registered just 18 cars there so far this year.In July, Nio registered three cars in Germany, down 93.6 per cent from a year earlier. It was the third consecutive month at that level, leaving its registrations in the first seven months nearly 90 per cent lower, according to the German Federal Motor Transport...