Abstract: A flow cell battery comprising on at least one side of a cell stack; a top electrolyte tank, a bottom electrolyte tank and at least one intermediate electrolyte tank arranged therebetween. The top electrolyte tank is in fluid communication with the bottom electrolyte tank through the cell stack. A first fluid communication is provided between the at least one intermediate electrolyte tank and the top electrolyte tank for flowing therebetween. A second fluid communication is provided between the at least one intermediate electrolyte tank and the bottom electrolyte tank for flowing therebetween. The second fluid communication comprises a controllable fluid flow restrictor. Each of the top, bottom and tanks comprise at least one gas connection for flowing gas in and out of each respective tank. A flowing device is provided for controlling a flow of electrolyte between the tanks.

Abstract: An open sided trailer construction in which a roof structure (4) is supported between front and rear frames (30,31) by a central fore and aft spine or web (5,21); the spine or web has lateral supports (8,26,27) extending either side of the web or spine which support a roof covering (4,28) and preferably extend to cantrails (7,20) from which hang curtains (3). The arrangement has the advantage that intermediate supports between the front and rear frame for the roof are not required and the cargo space within the trailer is easy to access and has a greater volume for a given trailer dimension than previous open sided trailer constructions.