The race to develop battery technology is not simply a question of finding ways to make electric vehicles easier to charge and more convenient to drive over long distances. Those are just factors in a complex game of global industrial competition and co-operation. The key issue is the location of one of the world’s most valuable manufacturing sectors: vehicle construction.

EVs are coming. There are some 2.5m on the roads worldwide, and the International Energy Agency predicts that number will rise to between 40m and 70m by 2025, with the prospect of subsequent strong global growth driven by the combination of regulation of traditional combustion engine vehicle use and falling battery costs.

Tesla of the US gets most of the publicity for its smart models and its financial problems, but the global leader is clearly China, which is home to three-quarters of the current fleet.