Flow batteries with current collectors having a dielectric coating
Herein is disclosed, a rechargeable flow battery, wherein the flow battery comprises: first and second electrodes, separated such that ions are allowed to flow between them, wherein a first reservoir comprising or for holding a first fluid electrolyte is fluidly connected to the first electrode, to allow circulation of the first fluid electrolyte from the first reservoir to the first electrode and from the first electrode to the first reservoir; and a first current collector comprising a layer of electrically conductive material having opposing first and second sides, wherein the first electrode is disposed on the first side of the first current collector, such that electrons can flow from the electrode to the first current collector, and a first layer of dielectric material is disposed on the second side of the first current collector.
1. A component for a rechargeable flow battery, wherein the component comprises:
a first current collector comprising a layer of electrically conductive material having opposing first and second sides, wherein a first electrode is disposed on the first side of the first current collector, such that electrons can flow from the first electrode to the first current collector, and a first layer of dielectric material is disposed on the second side of the first current collector;
wherein first and second apertures are provided through the first current collector and the first layer of dielectric material disposed on the second side of the first current collector to allow a first fluid to flow from the first aperture directly to, along, into, or past the first electrode and then out through the first current collector and dielectric material through the second aperture.
2. The component for a rechargeable flow battery according to claim 1 , wherein the dielectric material disposed on the second side of the first current collector is a printed circuit board material comprising a layer of fibre-reinforced polymer.
3. The component for a rechargeable flow battery according to claim 1 , wherein the dielectric material disposed on the second side of the first current collector is selected from FR-1, FR-2, FR-3, FR-4, FR-5, FR-6, CEM-1, CEM-2, CEM-3, CEM-4, CEM-5, polytetrafluoroethylene, G-10, G-11, alumina, polyimide, and woven fibreglass/PTFE laminates.
4. The component for a rechargeable flow battery according to claim 1 , wherein the electrically conductive material is selected from titanium, titanium nitride, molybdenum, brass and carbon, which may be or comprise graphitic carbon.
5. The component for a rechargeable flow battery according to claim 1 , wherein a protective annular member extends around the edge of the dielectric material defining the first and/or second aperture, to prevent contact of the first fluid with the dielectric material and any bonding agent materials contained therein.
6. The component for a rechargeable flow battery according to claim 5 , wherein the protective annular member is selected from an O-ring, X-ring and a D-ring.
7. The component for a rechargeable flow battery according to claim 1 , wherein a further layer of dielectric material is disposed on the first layer of dielectric material disposed on the second side of the first current collector, the further layer having channels and/or apertures formed therein for flow of the first fluid therethrough.
8. The component for a rechargeable flow battery according to claim 1 , wherein the flow battery comprises an all-vanadium couple, a hydrogen-vanadium couple, a hydrogen-lithium bromate couple, a hydrogen-lithium chlorate couple, a hydrogen-polyoxometalate couple, a bromine-hydrogen couple, an iron-tin couple, an iron-chrome couple, a bromine-polysulfide couple, a zinc bromine couple, a lead-acid (methane sulfonate) couple, a zinc-cerium couple, or a lead acid couple, or the flow battery is a lithium ion flow battery, an ionic-liquid flow battery, or a molten salt flow battery.
9. A rechargeable flow battery comprising the component for a rechargeable flow battery of claim 1 , wherein the battery also comprises a second electrode, and the first and second electrodes are separated such that ions are allowed to flow between them, wherein a first reservoir comprising or for holding the first fluid is fluidly connected to the first electrode, to allow circulation of the first fluid from the first reservoir to the first electrode and from the first electrode to the first reservoir.
10. The rechargeable flow battery of claim 9 , wherein the first and second electrodes are separated by a membrane, which may be selected from an ion selective membrane or a molecular sieve membrane, and a dielectric material is disposed between the membrane and the first current collector, wherein the dielectric material disposed between the membrane and the first current collector surrounds the first electrode.
11. The rechargeable flow battery of claim 10 , wherein the dielectric material disposed between the membrane and the first current collector is selected from FR-1, FR-2, FR-3, FR-4, FR-5, FR-6, CEM-1, CEM-2, CEM-3, CEM-4, CEM-5, polytetrafluoroethylene, G-10, G-11, alumina, polyimide, and woven fibreglass/PTFE laminates.
12. The rechargeable flow battery of claim 10 , wherein a protective annular member extends around an edge of the dielectric material disposed between the membrane and the first current collector, to prevent contact of the first fluid with the dielectric material.
13. The rechargeable flow battery according to claim 9 , wherein the flow battery comprises a stack, and wherein the stack comprises a plurality of cells, each cell comprising the first and second electrodes, wherein the first current collector of a cell in the stack is electrically connected to a second current collector of a neighbouring cell in the stack.
14. The rechargeable flow battery according to claim 13 , wherein each cell comprises a plurality of layers, and wherein one or more channels are present through the layers of each cell, but not through the first and second electrodes, to allow the first fluid to flow through a first cell to the first electrode of a second cell, and optionally to return to the first cell, and/or to allow a second fluid to flow through the second cell to the second electrode of the first cell, and optionally to return to the second cell.
15. The rechargeable flow battery according to claim 14 , wherein the channel(s) to allow the first fluid to flow from the first cell to the first electrode of the second cell is fluidly connected to the first and second apertures of the first cell.
16. The rechargeable flow battery according to claim 13 , wherein the first current collector of a cell in the stack is electrically connected to the second current collector of a neighbouring cell in the stack via removable electrical connections to allow removal of one cell from the stack, and re-connection of the remaining cells in the stack to allow the cells to continue functioning with a removed cell.
17. The rechargeable flow battery according to claim 13 , wherein the cells are bonded together.