Fuel cell

1. A fuel cell comprising:

a fuel electrode and an oxidizing agent electrode;

a fuel supply path configured to supply a liquid fuel to the fuel electrode; an oxidizing agent supply path configured to supply an oxidizing agent to the oxidizing agent electrode; and

an opening/closing member configured to open and close said oxidizing agent supply path by changing its shape,

wherein said opening/closing member is configured to cover said oxidizing agent electrode by changing its shape.

2. The fuel cell according to claim 1 , further comprising;

a gas guide unit configured to input gas into a closed space formed by said opening/closing member and said oxidizing agent electrode,

wherein said opening/closing member is separated from said oxidizing agent electrode by the gas being inputted to said closed space to open said oxidizing agent supply path.

3. The fuel cell according to claim 1 , wherein said opening/closing member is a bag unit configured to be able to expand and shrink.

4. The fuel cells according to claim 3 , further comprising;

a gas guide unit configured to input gas into said bag unit.

5. The fuel cells according to claim 3 , wherein said gas guide unit is configured to input said oxidizing agent into said bag unit.

6. The fuel cells according to claim 1 , wherein said opening/closing member is a plate configured to be combined at least two plate-like members, and

coefficient of thermal expansion of said at least two plate like-members are different.

7. The fuel cells according to claim 6 , wherein said plate is combined a metal plate-like member and a resin plate-like member.

8. The fuel cells according to claim 6 , wherein said plate is combined metal plate-like members.