Electrochemical fuel cell stack with an improved compression assembly

An electrochemical fuel cell stack comprising:

• a first end plate;
• a second end plate;
• a fuel cell assembly interposed between said first and second end plates;
• and
• a compression assembly associated with said first and second end plates, said compression assembly comprising:
• a resilient member which urges said first end plate towards said second end plate;
• an elongate tension member, with a longitudinal axis, extending between said first end plate and said second end plate;
• and
• a restraining member which is engaged with said tension member in the direction of said longitudinal axis of said tension member, wherein said restraining member cooperates with said tension member to transmit a tension load to said tension member from said fuel cell stack and wherein said restraining member comprises a collet through which said tension member is inserted and a wedge inserted between said tension member and said collet, said wedge cooperating with said collet to grip said tension member.

A method of assembling a compression assembly for an electrochemical fuel cell stack comprising at least one fuel cell assembly interposed between a first end plate and a second end plate, said method comprising the steps of:

• (a) extending a longitudinal axis of a tension member through a first end plate and a second end plate of said fuel cell stack;
• (b) applying a compressive force to said fuel cell stack in a direction parallel to said longitudinal axis, wherein said compressive force engages a restraining member with said tension member, and compresses a resilient member until it is in equilibrium with said compressive force;
• and
• (c) placing a resilient member over an end of said tension member, such that a through opening in said resilient member receives said end of said tension member, and
• the step of engaging said restraining member comprises employing said compressive force to insert at least one wedge into a gap between said tension member and said resilient member.

A method of assembling a compression assembly for an electrochemical fuel cell stack comprising at least one fuel cell assembly interposed between a first end plate and a second end plate, said method comprising the steps of:

• (a) extending a longitudinal axis of a tension member through a first end plate and a second end plate of said fuel cell stack;
• (b) applying a compressive force to said fuel cell stack in a direction parallel to said longitudinal axis, wherein said compressive force engages a restraining member with said tension member, and compresses a resilient member until it is in equilibrium with said compressive force;
• and
• (c) placing a resilient member over an end of said tension member, such that a through opening in said resilient member receives said end of said tension member;
• (d) placing a collet over an end of said tension member and extending said tension member through said collet;
• and
• the step of engaging said restraining member comprises employing said compressive force to insert at least one wedge into a gap between said tension member and said collet until said resilient member is compressed and in equilibrium with said compressive force.

A method of assembling a compression assembly for an electrochemical fuel cell stack comprising at least one fuel cell assembly interposed between a first end plate and a second end plate, said method comprising the steps of:

• (a) extending a longitudinal axis of a tension member through a first end plate and a second end plate of said fuel cell stack;
• (b) applying a compressive force to said fuel cell stack in a direction parallel to said longitudinal axis, wherein said compressive force engages a restraining member with said tension member, and compresses a resilient member until it is in equilibrium with said compressive force;
• and
• the step of engaging said restraining member comprises inserting an end of said tension member through an opening in said resilient member and engaging said tension member through an opening in said resilient member and engaging said tension member with said resilient member by deflecting spring arms which are unitary with said resilient member.