Fuel cell module

1. A fuel cell module comprising:

a cell stack configured to include a plurality of fuel cells that are stacked, the fuel cells being configured to generate electric power using an oxygen-containing gas and a hydrogen-containing gas;

a package configured to house the cell stack in a space surrounded by a package wall;

at least one bus bar configured to include one end electrically connected to an electrode terminal in the package of the cell stack, and include another end positioned outside the package through a through hole in the package wall, the at least one bus bar including a spring mechanism in the package, wherein an expanding direction of the spring mechanism is the same as a projecting direction of the bus bar; and

an electrically insulating member configured to enclose a gap between the bus bar and the package with the bus bar and the package electrically insulated from each other, and configured to fix the bus bar to the package wall,

wherein the electrically insulating member comprises:

a first electrically insulating member including a guide hole portion therein through which the bus bar is inserted;

a wedge disposed in a gap between the guide hole portion of the first electrically insulating member and the bus bar; and

a second electrically insulating member configured to seal a gap between the first electrically insulating member and the bus bar.

2. The fuel cell module according to claim 1 , wherein the spring mechanism has a restoring force generated by a metal elastic body.

3. The fuel cell module according to claim 2 , wherein the spring mechanism is at least one of a helical spring and a metal elastic body having a U-like shape.

4. The fuel cell module according to claim 3 , wherein the U-like shape is a U-like shape in which a gap in an opened portion is narrower than gaps of other portions.

5. The fuel cell module according to claim 1 , wherein the bus bar is separable into two or more pieces, one of separated pieces of the bus bar includes an internal thread feature, and another one of the separated pieces of the bus bar includes an external thread feature.

6. The fuel cell module according to claim 5 , wherein, of the pieces of the bus bar, an outer bus bar in a region that is in contact with the electrically insulating member differs in material from an inner bus bar in a region that is closer to the electrode terminal than the outer bus bar.

7. The fuel cell module according to claim 6 , wherein a shape of at least a region in the outer bus bar that is in contact with the electrically insulating member is a column-like shape.

8. The fuel cell module according to claim 6 , wherein the inner bus bar is plate-like and includes the spring mechanism.

9. The fuel cell module according to claim 1 , wherein a number of the at least one bus bar is more than one, and one of the bus bars is connected to a voltage terminal that is provided on a stacking surface of the cell stack to measure voltage.

10. The fuel cell module according to claim 1 , wherein a number of the at least one bus bar is more than one, and one of the bus bars is connected to a voltage terminal that is provided on a stacking surface of the cell stack to measure voltage, and including another end disposed outside the package, the one of the bus bars including a spring mechanism in the package.