Arrangement of flow structures for use in high differential pressure electrochemical cells
The present disclosure is directed towards flow structures in electrochemical cells for use in high differential pressure operations. The flow structure on the low pressure-side of the cell has a larger surface area than the flow structure on the high-pressure side of the cell at the flow structure—MEA interface. The boundary of the high pressure flow structure is entirely within the boundary of the low pressure flow structure. A seal around the high pressure flow structure is also contained within the boundary of the low pressure flow structure. In such an arrangement, high fluid pressures acting on the electrolyte membrane from the high-pressure side of the cell is fully and continuously balanced by the flow structure on the low pressure-side of the membrane. Use of the low pressure flow structure as a membrane support prevents the rupture or deformation of the membrane under high stresses.
1. An electrochemical cell comprising:
a first electrode, a second electrode, and an electrolyte membrane disposed therebetween;
a first flow structure adjacent to the first electrode, the first flow structure comprising a first planar surface along a side facing the-electrode;
a second flow structure adjacent to the second electrode, the second flow structure comprising a second planar surface along a side facing the electrode; and
a seal around the second flow structure, wherein the seal surrounds an outermost perimeter of the second flow structure;
wherein a perimeter of the second electrode is entirely within a perimeter of the first electrode;
wherein the first flow structure is configured to withstand higher structural force than the second flow structure;
wherein an area of the first planar surface is larger than an area of the second planar surface; and
wherein the entire seal is located outside a boundary of the second planar surface and within a boundary of the first planar surface.
2. The electrochemical cell of claim 1 , wherein the boundary of the second planar surface is within the boundary of the first planar surface.
3. The electrochemical cell of claim 1 , wherein the seal comprises a polymeric gasket.
4. The electrochemical cell of claim 1 , wherein the first flow structure comprises a compacted porous metallic substrate.
5. The electrochemical cell of claim 4 , wherein the first flow structure is compacted to a density level greater than that of the second flow structure.
6. The electrochemical cell of claim 4 , wherein the first flow structure comprises at least one micro-porous material layer laminated onto the compacted porous metallic substrate.
7. The electrochemical cell of claim 1 , wherein the second flow structure comprises a porous metallic substrate.
8. The electrochemical cell of claim 7 , wherein the second flow structure comprises at least one micro-porous material layer laminated onto the porous metallic substrate.
9. The electrochemical cell of claim 1 , further comprising a bipolar plate positioned adjacent to the second flow structure.
10. The electrochemical cell of claim 9 , further comprising a reinforcement layer between the bipolar plate and the electrolyte membrane, wherein the reinforcement layer is positioned around the outside of the perimeter of the second electrode.
11. The electrochemical cell of claim 10 , wherein the reinforcement layer is bonded onto the electrolyte membrane.