ENERGY STORAGE SYSTEM AND COOLING ARRANGMENT FOR A VEHICLE AND METHODS

The present disclosure relates to an energy storage tank (10) defining a tank volume for said heat transfer fluid, and comprising a partition (12) dividing said tank volume into a first volume (V1) and a second volume (V2), whereinsaid partition (12) is movable to/from any position between a minimum energy storage position corresponding to a minimum second volume (V2), and a maximum energy storage position corresponding to a maximum second volume (V2),said energy storage tank further comprising a biasing device (18) being arranged such that movement of the partition (12) away from said minimum energy storage position corresponds to storing energy in said biasing device (18), and movement towards the minimum energy storage position corresponds to releasing energy from said biasing device (18); said energy storage system further comprising a heat transfer fluid duct (20) connecting said first volume (V1) and said second volume (V2), anda heat transfer arrangement (40) arranged for altering the temperature of the transfer fluid from a first temperature when in the first volume (V1) to a second temperature when in the second volume (V2),and said energy storage system (100) further comprising a fluid control assembly (30) for providing a pressure implying a flow of said heat transfer fluid from said first volume (V1) to said second volume (V2) via said heat transfer fluid duct (20).