The US electric car maker Tesla intends to grow from a niche supplier to a mass manufacturer;

Vehicle sales are expected to increase by 50 percent per year.

If that worked, the company would reach the size of BMW or Mercedes-Benz by the middle of the decade.

But current figures show - the way there has become astonishingly long.

Elon Musk is suddenly struggling with several difficulties, which, at least in their totality, certainly cast doubt on the business model.