An electrochemical cell has a membrane located between two flow field plates. On a first side of the membrane, there is a porous support surrounded by a seal between the membrane and the flow field plate. There is a gap between the porous support and the seal at the surface of the membrane. On a second side of the membrane, there is a seal between the membrane and the flow field plate located inside of the gap in plan view. The electrochemical cell is useful, for example, in high pressure or differential pressure electrolysis in which the second side of the membrane will be consistently exposed to a higher pressure than the first side of the membrane.