Fuel cell stack
Provided is a fuel cell stack capable of suppressing damage to a seal member and suppressing leakage of a reaction gas to the outside of a casing or entry of water from the outside of the casing for a long period of time. The fuel cell stack includes a pair of end plates and holds a laminate from two sides in a direction, a casing which houses the laminate and has connection bars extended between the pair of end plates, a fastening member inserted into an end plate side mounting hole and a connection bar side mounting hole, and chamfered parts formed in an end plate side small diameter part of the end plate side mounting hole. A chamfer angle between an inner surface of the outer chamfered part and the direction is larger than a chamfer angle between an inner surface of the inner chamfered part and the direction.
1. A fuel cell stack, comprising:
a fuel cell laminate in which a plurality of fuel battery cells are laminated in a first direction;
a casing housing the fuel cell laminate, the casing comprising a pair of end plates that holds the fuel cell laminate from two sides in the first direction and a connection member that is extended between the pair of end plates;
a fastening member fastening the end plates and the connection member in the first direction;
a cylindrical knock arranged to extend in an end plate side mounting hole of the end plate and a connection member side mounting hole of the connection member, through which the fastening member is inserted, in the first direction and externally fitted to the fastening member in the end plate side mounting hole and the connection member side mounting hole;
a first seal member externally fitted to the cylindrical knock in the end plate side mounting hole and being in close contact with an inner peripheral surface of the end plate side mounting hole and the cylindrical knock;
a second seal member externally fitted to the cylindrical knock in the connection member side mounting hole and being in close contact with an inner peripheral surface of the connection member side mounting hole and the cylindrical knock;
an outer chamfered part formed on an outer opening edge, which is open on a side opposite to the connection member side mounting hole in the first direction, in the end plate side mounting hole; and
an inner chamfered part formed on an inner opening edge, which is open to the connection member side mounting hole in the first direction, in the end plate side mounting hole,
wherein a chamfer angle between an inner surface of the outer chamfered part and the first direction is larger than a chamfer angle between an inner surface of the inner chamfered part and the first direction.
2. The fuel cell stack according to claim 1 , wherein a maximum inner diameter of the outer chamfered part is larger than an outer shape of the first seal member and the second seal member in a front view as viewed from the first direction.
3. The fuel cell stack according to claim 1 , wherein a curved surface part that is convex toward an inside of the end plate side mounting hole is formed at a boundary portion between the inner surface of the outer chamfered part and an outer end surface, which is continuous with the inner surface of the outer chamfered part and faces outward in the first direction, in the end plate.
4. The fuel cell stack according to claim 2 , wherein a curved surface part that is convex toward an inside of the end plate side mounting hole is formed at a boundary portion between the inner surface of the outer chamfered part and an outer end surface, which is continuous with the inner surface of the outer chamfered part and faces outward in the first direction, in the end plate.