Tank system of a motor vehicle, with a volume changing element

The invention relates to a tank system of a motor vehicle with an interior of the fuel tank is at least substantially provided above the liquid level change in volume element which is in the form of a deformable bag which forms a related with the environment compensation volume, in particular with one of the claims 1 to 3 of the WO 2016/012284 Which is held in spiral form in the interior of the fuel tank or positioned or fixed features contained, wherein the volume changing element is formed as a tubular elongated bag.