Humidifier for fuel cell

1 . A humidifier for a fuel cell, the humidifier comprising a humidifying unit that provides moisture contained in water-containing air to dry air to produce humidified air, wherein

the humidifying unit includes

a first separator that is in a form of a plate and that includes a dry gas channel in a central region of one surface of the first separator,

a second separator that is in a form of a plate and that includes a water-containing gas channel in a central region of a surface of the second separator that faces the dry gas channel,

a humidifying membrane that is located between the dry gas channel and the water-containing gas channel, and that provides moisture contained in gas flowing through the water-containing gas channel to the dry air flowing through the dry gas channel to produce humidified air,

two protective films that reinforce the humidifying membrane, the protective films include a first protective film stacked respectively on a front of the humidifying membrane and a second protective film stacked on a back of the humidifying membrane, and

a sealing material that is provided along a first outer edge portion of the humidifying membrane with the humidifying membrane and the protective films stacked together, and that seals between the dry gas channel and the water-containing gas channel, a second outer edge portion of one of the first protective film of the second protective film is shorter than the first outer edge portion of the humidifying membrane so that the humidifying membrane has a close contact region between the first outer edge portion and the second outer edge portion, a third outer edge portion of the other of the first protective film and the second protective film aligns with the first outer edge portion of the humidifying membrane, and

the sealing material is provided along the second outer edge portion, the third outer edge portion, a surface of the humidifying membrane between the first outer edge portion and the second outer edge portion, and a surface of the one of the first protective film and the second protective film that is opposite to the humidifying membrane.

2 . The humidifier for a fuel cell according to claim 1 , wherein

a reinforcing member is provided on an opposite side from the humidifying membrane so as to face at least one of the protective films, and

the reinforcing member together with the humidifying membrane and the protective films is sandwiched by the sealing material between the first separator and the second separator.

3 . The humidifier for a fuel cell according to claim 2 , wherein the reinforcing member is provided in contact with the protective film located between the second separator and the humidifying membrane.

4 . The humidifier for a fuel cell according to claim 1 , wherein the humidifying membrane has the close contact region on at least one of surfaces of the humidifying membrane.

5 . The humidifier for a fuel cell according to claim 4 , wherein the humidifying membrane has the close contact region on a surface that faces the first separator.

6 . The humidifier for a fuel cell according to claim 1 , wherein the humidifying membrane and the protective films have a plurality of portions parallel to each other, and the close contact region has a same width in all of the plurality of parallel portions.

7 . The humidifier for a fuel cell according to claim 6 , wherein at least corners of the first outer edge portion of the humidifying membrane have a circular arc shape, and a width of the close contact region in the corners is equal to a width of the close contact region in the plurality of parallel portions so that the close contact region has the same width in an entire periphery of the humidifying membrane.

8 . The humidifier for a fuel cell according to claim 7 , wherein corners of

the second outer edge portion of the protective film have a circular arc shape.