Systems and methods of fuel cell stack compression
An electrochemical-cell stack assembly is provided. The assembly has an electrochemical-cell stack and a compression system that holds the electrochemical-cell stack in a state of compression. The compression system has a first endplate and a second endplate positioned at opposite ends of the electrochemical-cell stack. The compression system has a set of tension members coupled to the first endplate and the second endplate that maintain a fixed distance between the first endplate and the second endplate. The compression system has a compression plate disposed between the second endplate and the electrochemical-cell stack. The compression system has a compression member in contact with the compression plate, wherein the compression member is configured to transfer a force to the compression plate. The compression system has a locking nut fastened to the second plate. The locking nut secures the position of the compression member and compression plate relative to the second endplate.
1. A method of compressing an electrochemical-cell stack, comprising:
placing an electrochemical-cell stack on a first endplate;
positioning a compression plate on the electrochemical-cell stack at an end opposite the first endplate;
arranging one or more compression members on the compression plate;
positioning a second endplate over the compression plate so that the one or more compression members align with one or more openings in the second endplate;
applying a force to the compression plate through the one or more compression members until the electrochemical-cell stack is compressed to a predetermined height ranging from 50% to 80% of an uncompressed height of the stack;
attaching one or more tension members to the first endplate and the second endplate, wherein the one or more tension members are configured to maintain a fixed distance between the first endplate and the second endplate; and
fastening one or more locking nuts to the second endplate, wherein the one or more locking nuts are configured to secure the position of the one or more compression members and the compression plate relative to the second endplate.
2. The method of claim 1 , wherein arranging the one or more compression members comprises evenly distributing at least one of the one or more compression members over an active area of the electrochemical stack.
3. The method of claim 1 , wherein at least one of the one or more compression members comprises a stack of belleville-washers and a compression cap.
4. The method of claim 1 , wherein the one or more locking nuts are positioned for fastening to the second endplate prior to applying the force to the compression plate.
5. The method of claim 1 , wherein at the predetermined height, sets of holes at each end of the one or more tension members align with a set of holes in the first endplate and a set of holes in the second endplate.
6. The method of claim 1 , further comprising:
attaching the one or more tension members to the first endplate prior to placing the electrochemical-cell stack on the first endplate; and
aligning the electrochemical-cell stack on the first endplate using the one or more tension members attached to the first endplate.
7. The method of claim 1 , further comprising tightening the one or more locking nuts to a predetermined torque value.