Electrode assembly and flow battery with improved electrolyte distribution
An electrode assembly for a flow battery is disclosed comprising a porous electrode material, a frame surrounding the porous electrode material, at least a distributor tube embedded in the porous electrode material having an inlet for supplying electrolyte to the porous electrode material and at least another distributor tube embedded in the porous electrode material having an outlet for discharging electrolyte out of the porous material. The walls of the distributor tubes are preferably provided with holes or pores for allowing a uniform distribution of the electrolyte within the electrode material. The distributor tubes provide the required electrolyte flow path length within the electrode material to minimize shunt current flowing between the flow cells in the battery stack.
1. A flow battery comprising at least one flow cell which comprises:
a negative electrode assembly and a positive electrode assembly;
a separator separating the positive electrode assembly and the negative electrode assembly; and
a first and a second bipolar plate, each bipolar plate being adjacent to a respective electrode assembly;
wherein at least one of the negative or positive electrode assemblies is an electrode assembly comprising:
a porous electrode material;
a frame surrounding the porous electrode material;
at least a first distributor tube embedded in the porous electrode material, the first distributor tube having an inlet for supplying electrolyte to the porous electrode material; and
at least a second distributor tube embedded in the porous electrode material, the second distributor tube having an outlet for discharging electrolyte out of the porous electrode material;
wherein the frame and the distributor tubes are made of an electrically non-conductive plastic material; and
wherein the first distributor tube and the second distributor tube are hollow tubes each having an interior flow passage and a wall surrounding the interior passage, wherein the wall of the hollow tubes is made of a solid material provided with at least one hole to allow the flow of electrolyte through the wall of the distributor tube into the porous electrode material.
2. The flow battery claim 1 wherein the first and second distributor tubes extend between a first side of the frame and a second side of the frame, beyond the midpoint of the electrode assembly between the two sides of the frame.
3. The flow battery of claim 1 wherein the first distributor tube has an outlet sealed to the frame and the second distributor tube has an inlet sealed to the frame.
4. The flow battery of claim 1 wherein the first distributor tube has an outlet open to the porous electrode material and the second distributor tube has an inlet open to the porous electrode material.
5. The flow battery of claim 1 wherein at least one of the first or second distributor tubes has a circular cross-section.
6. The flow battery of claim 1 wherein at least one of the first or second distributor tubes has a triangular cross-section.
7. The flow battery of claim 1 wherein at least one of the first or second distributor tubes is entirely embedded within the porous electrode material.
8. The flow battery of claim 1 wherein at least one of the first or second distributor tubes is partially embedded in the porous electrode material.
9. The flow battery of claim 1 comprising a plurality of first and second distributor tubes which are evenly distributed across the area of the porous electrode material.
10. The flow battery of claim 1 comprising a plurality of first and second distributor tubes of equal cross-sectional flow areas.
11. The flow battery of claim 1 wherein the length of the first distributor tube is equal to the length of the second distributor tube.
12. The flow battery of claim 1 wherein the first and second distributor tubes are made of polyethylene or polypropylene.