JP2008097967A - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain flow of gas into a gap between a porous body and a frame without the need of providing a sealing member anew and prevent degradation of power generating efficiency of a fuel cell due to gas flowing into the gap. <P>SOLUTION: The fuel cell is provided with a membrane electrode assembly 30, a porous body 350 in adjacency to the membrane electrode assembly 30 for diffusing gas flowing in a given direction consisting of a first porous body part 350b and a second porous body part 350c divided aslant against a flowing direction of gas, and a frame 300 with an opening 320 supporting the membrane electrode assembly 30 and the porous body 350. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel cell, and more particularly to the shape and arrangement of a porous body that diffuses fuel gas or oxidizing gas.

  There is known a fuel cell that uses a porous body as a flow path for fuel gas or oxidizing gas, diffuses the fuel gas or oxidizing gas in the porous body, and supplies the fuel electrode or oxidizing gas to the membrane electrode assembly to generate power ( Patent Document 1). However, in the conventional configuration, a gap is generated between the opening of the frame and the porous body due to an assembly error when the porous body is assembled in the opening of the frame. Since the fuel gas or the oxidizing gas flowing through the generated gap is discharged without being used for the power generation reaction, there is a problem that the power generation efficiency of the fuel cell is lowered. On the other hand, a technique for inserting a seal member into the gap between the frame and the porous body is known (Patent Document 2).

JP 2004-87318 A JP 2004-119121 A

  However, there is a problem that a seal member is newly required. In addition, when the seal member is used, the power generation efficiency of the fuel cell may be reduced if gas leaks into the gap due to aging of the seal member.

  The present invention solves at least one of the above problems, suppresses gas from flowing in the gap between the porous body and the frame without using a seal member, and prevents and suppresses a decrease in power generation efficiency of the fuel cell. Objective.

  The fuel cell according to the present invention includes a membrane electrode assembly and a porous body that diffuses a gas that flows adjacent to the membrane electrode assembly and flows in a predetermined direction, and is divided obliquely with respect to the direction in which the gas flows. A porous body having one porous body portion and a second porous body portion; and a frame having an opening for supporting the membrane electrode assembly and the porous body therein. According to the fuel cell of the present invention, since the porous body is divided into the first porous body portion and the second porous body portion, the first porous body portion and the second porous body portion are formed so that no gap is generated in the gas flow direction. Two porous body portions can be arranged. Therefore, a sealing member for suppressing the gas gap flow is not necessary. Furthermore, since the gas gap flow can be suppressed, it is possible to prevent and suppress a decrease in power generation efficiency of the fuel cell.

  In the fuel cell according to the present invention, the shape of the porous body and the shape of the opening are rectangular. According to the fuel cell of the present invention, since the shape of the porous body and the shape of the opening are rectangular, for example, the first porous body portion and the second porous body portion are arranged to be shifted along the dividing line. Thus, the side of the porous body and the side of the opening can be easily adhered. As a result, no gap can be generated, and a seal member for suppressing the gas gap flow is not necessary. Furthermore, since the gas gap flow can be suppressed, it is possible to prevent and suppress a decrease in power generation efficiency of the fuel cell.

  In the fuel cell according to the present invention, the first porous body portion and the second porous body portion may be configured such that one side of the first porous body portion is two sides of the opening parallel to the gas flow direction. One side of the second porous body portion is in contact with a second side different from the first side of the two sides of the opening parallel to the gas flow direction. The first porous body part and the second porous body part are in contact with each other and are arranged in the opening. According to the fuel cell of the present invention, the first porous body portion and the opening are in close contact, the second porous body portion and the opening are in close contact, and the first porous body portion and the second porous body portion are in contact with each other. It is in close contact. As a result, there is no gap in the direction of gas flow, and therefore a seal member for suppressing the gas gap flow is not required. Furthermore, since the gas gap flow can be suppressed, it is possible to prevent and suppress a decrease in power generation efficiency of the fuel cell.

  In the fuel cell according to the present invention, an angle formed between the gas flow direction and the dividing line is smaller than an angle formed between the gas flow direction and a diagonal line of the porous body, and the first porous body portion. And the shape of the second porous body portion are trapezoidal. According to the fuel cell of the present invention, the seal length of the contact portion between the first porous body portion and the opening portion and the seal length of the contact portion between the second porous body portion and the opening portion in the gas flow direction are: The length of the porous body is the same as the length of the gas flow direction, and the seal length can be maximized. As a result, the gap between the porous body and the opening can be minimized, and the power generation efficiency of the fuel cell can be increased.

  In the fuel cell according to the present invention, the dividing line coincides with a diagonal line of the porous body. According to the fuel cell of the present invention, the seal length between the first porous body portion and the opening and the seal length between the second porous body portion and the opening in the gas flow direction are the gas flow of the porous body. The length becomes the same as the length in the direction, and the seal length between the first porous body portion and the opening and the seal length between the second porous body portion and the opening can be made the longest. Furthermore, the tolerance with respect to the length of the gap between the opening and the porous body in the direction perpendicular to the gas flow direction can be increased. That is, when the length of the gap between the opening and the porous body is greater than or equal to a predetermined length in the direction perpendicular to the gas flow direction, how the first porous body portion and the second porous body portion are arranged. However, according to the fuel cell according to the present invention, the length of the gap between the opening and the porous body in the direction perpendicular to the gas flow direction is the gas flow direction. It is possible to increase the limit for preventing the occurrence of a gap.

  In the fuel cell according to the present invention, the angle θ formed by the direction in which the gas flows and the dividing line is such that the value of the tangent to the angle is between the porous body and the opening in a direction perpendicular to the direction in which the gas flows. It is an angle that is equal to or greater than the value obtained by dividing the gap length x1 by the length y1 of the gap between the porous body and the opening in the direction parallel to the gas flow direction. According to the fuel cell of the present invention, the porous body is divided into the first porous body portion and the second porous body portion at an angle θ satisfying tan θ ≧ x1 / y1, so that the gap in the gas flow direction Can be prevented.

  In the fuel cell according to the present invention, the length y1 of the gap between the porous body and the opening in a direction parallel to the gas flow direction is such that the porous body in the direction perpendicular to the gas flow direction It is formed to have a size equal to or greater than a value obtained by dividing the length x1 of the gap between the openings by the tangent value of the angle θ formed by the gas flow direction and the dividing line. According to the fuel cell of the present invention, when the angle θ between the gas flow direction and the dividing line is constant, the gap between the porous body and the opening in the direction parallel to the gas flow direction is determined. Since the porous body is formed so that the length y1 satisfies y1 ≧ x1 / tan θ, a gap in the gas flowing direction can be prevented from being generated.

  In the fuel cell according to the present invention, the second porous body portion is further divided into a plurality of porous body portions. According to the fuel cell of the present invention, since the degree of freedom of arrangement of the porous body portion is further increased, it is easy to arrange the porous body portion so that there is no gap in the gas flow direction. As a result, a seal member for suppressing the gas gap flow is not necessary. In addition, since the gas gap flow can be suppressed, it is possible to prevent and suppress a decrease in power generation efficiency of the fuel cell.

  In the fuel cell according to the present invention, the frame further includes positioning means for determining a position of the divided porous body portion. According to the fuel cell of the present invention, since the frame includes positioning means for determining the position of the divided porous body portion, the porous body portion is provided so that no gap is generated between the porous body portion and the frame. Easy to place

  In the fuel cell according to the present invention, the positioning means is provided on one side of the frame and perpendicular to the gas flow direction in the divided porous body portion, and the first porous body portion is The porous body part different from the first porous body part is pressed against one side of the frame and parallel to the gas flow direction. According to the fuel cell of the present invention, the porous body portion is directed to the gas flow direction by the resultant force of the pressure on the side perpendicular to the gas flow direction in the porous body portion and the normal force from the other porous body portions. Force is applied in the vertical direction and pressed against the frame. As a result, the porous body portion and the frame strongly adhere to each other, and a gap is hardly generated.

  Embodiments of the present invention will be described with reference to the drawings. The outline of the fuel cell according to the present embodiment will be described with reference to FIG. FIG. 1 is a perspective view schematically showing the appearance of a fuel cell 10 according to an embodiment of the present invention. The fuel cell 10 is configured by alternately stacking separator portions 20 and membrane electrode assembly portions 30. The fuel cell 10 has an oxidizing gas supply manifold 102 on the upper side (z axis plus side) of the fuel cell shown in FIG. 1, an oxidizing gas discharge manifold 104 on the lower side (z axis minus side), and a left side (x axis minus side). ) Includes a fuel gas supply manifold 106 and a cooling water supply manifold 110, and a fuel gas discharge manifold 108 and a cooling water discharge manifold 112 on the right side (x-axis plus side). These manifolds 102 to 112 penetrate in the stacking direction (y-axis direction).

  The structure of the fuel cell 10 according to the present invention will be described with reference to FIG. FIG. 2 is an explanatory view schematically showing a cross section of the fuel cell 10 shown in FIG. 1 taken along a plane parallel to the yz plane.

  In this embodiment, the separator unit 20 includes, for example, an intermediate plate 200 made of a resin laminate film, and an anode side plate 220 and a cathode side plate made of, for example, a metal material that sandwich the intermediate plate 200 from both sides. 240.

  The membrane / electrode assembly 30 includes a membrane / electrode assembly 40, a porous body 350 and a porous body 351 adjacent to both surfaces of the membrane / electrode assembly 40, and a membrane / electrode assembly 40, a porous body 350, and a porous body 351, respectively. And a supporting frame 300. The membrane electrode assembly 40 includes an electrolyte membrane 400 and catalyst layers 420 and 421 adjacent to both surfaces of the electrolyte membrane 400, respectively.

  The porous body 350 and the porous body 351 are members that form a flow path for the oxidizing gas and the fuel gas, respectively. The porous body 350 and the porous body 351 are also members for diffusing the oxidizing gas and the fuel gas flowing therein. In this embodiment, as the porous body 350 and the porous body 351, for example, a stainless porous body is used. As the frame 300, for example, a frame formed of an insulating resin material such as silicon rubber, butyl rubber, or fluorine rubber is used. As the electrolyte membrane 400, a proton conductive ion exchange membrane made of a solid polymer material, for example, a fluorine resin such as perfluorocarbon sulfonic acid polymer is used. As the catalyst layer 420 and the catalyst layer 421, a catalyst layer in which a catalyst that promotes an electrochemical reaction, for example, a platinum catalyst or a platinum alloy catalyst made of platinum and another metal is supported on a support such as carbon black, for example. Is used.

  The intermediate plate 200, the anode side plate 220, the cathode side plate 240, and the frame 300 are formed with oxidizing gas supply manifold forming holes 202, 222, 242 and 302 for forming the oxidizing gas supply manifold 102, respectively. . The anode side plate 220, the cathode side plate 240, and the frame 300 are formed with oxidizing gas discharge manifold forming holes 204, 224, 244, 304 for forming the oxidizing gas discharge manifold 104, respectively.

  The cathode side plate 240 has an oxidizing gas introduction hole 256 for guiding the oxidizing gas supplied from the oxidizing gas supply manifold 102 to the porous body 350 adjacent to the outside of the separator unit 20 via the inside of the separator unit 20. An oxidizing gas outlet hole 258 for guiding the unreacted oxidizing gas from the porous body 350 to the oxidizing gas discharge manifold 104 through the inside of the separator portion 20 is formed.

  The intermediate plate 200 is formed with an oxidizing gas supply manifold forming hole 202 and an oxidizing gas supply communicating portion 216 that connects the oxidizing gas supply manifold forming hole 202 and the oxidizing gas introduction hole 256 to each other. The forming hole 204 is formed with an oxidizing gas discharge communicating portion 218 that communicates the oxidizing gas discharge manifold forming hole 204 and the oxidizing gas outlet hole 258.

  The oxidizing gas is supplied from the oxidizing gas supply manifold 102 to the porous body 350 via the oxidizing gas supply manifold forming hole 202, the oxidizing gas supply communication portion 216, and the oxidizing gas introduction hole 256, and the unreacted oxidizing gas is Then, the oxidant gas is discharged to the oxidant gas discharge manifold 104 via the oxidant gas outlet hole 258, the oxidant gas discharge communication part 218, and the oxidant gas discharge manifold forming hole 204.

  The structure of the membrane electrode assembly part 30 will be described with reference to FIG. FIG. 3 is a plan view schematically showing the membrane electrode assembly 30. In FIG. 3, the membrane electrode assembly 40 and the deep porous body 351 are not shown in the drawing because they are hidden by the porous body 350 on the near side.

  At the center of the frame 300, a rectangular opening 320 surrounded by four sides 320a, 320b, 320c, and 320d is formed. In FIG. 3, an oxidizing gas supply manifold forming hole 302 is formed on the upper side of the opening 320 of the frame 300, an oxidizing gas discharge manifold forming hole 304 is formed on the lower side, and a fuel gas supply manifold is formed on the left side. A hole 306 and a cooling water supply manifold forming hole 310 are formed, and a fuel gas discharge manifold forming hole 308 and a cooling water discharge manifold forming hole 312 are formed on the right side.

  The near-side porous body 350 has a rectangular shape, and the dividing line 350a has a smaller angle between the direction in which the oxidizing gas flows and the angle between the direction in which the oxidizing gas flows and the diagonal line of the porous body 350. Thus, the first porous body portion 350b and the second porous body portion 350c are divided. Here, in this embodiment, the oxidizing gas is supplied from the oxidizing gas supply manifold forming hole 302, passes through the first porous body portion 350 b and the second porous body portion 350 c, and then becomes the oxidizing gas discharge manifold forming hole 304. To be discharged. Therefore, the direction in which the oxidizing gas flows is the direction from the top to the bottom in FIG.

  The first porous body portion 350b has a trapezoidal shape. The first porous body portion 350b has a base 350d on the top, a bottom 350e on the bottom, a side 350f on the left, and a divided portion 350g on the upper right. Prepare. The second porous body portion 350c has a trapezoidal shape, and has a base 350h at the top of the second porous body 350c, a bottom 350i at the bottom, a split portion 350j at the bottom left, and a side 350k at the right. Prepare. The side 350f of the first porous body 350b and the side 320c of the opening are in close contact with each other, the side 350k of the second porous body 350c and the side 320d of the opening are in close contact with each other, and the first porous The divided part 350g of the body part 350b and the divided part 350j of the second porous body part 350c are in close contact with each other. As a result, there is no gap from the oxidizing gas supply manifold forming hole 302 to the oxidizing gas discharge manifold forming hole 304 in the direction in which the oxidizing gas flows. Therefore, a seal member for filling the gap is not necessary.

  The oxidizing gas always passes through at least one or both of the first porous body portion 350b and the second porous body portion 350c on the path from the oxidizing gas supply manifold forming hole 302 to the oxidizing gas discharge manifold forming hole 304. pass. In general, when an oxidizing gas flows, if a gap in which the oxidizing gas flows without passing through either the first porous body portion 350b or the second porous body portion 350c is generated, the oxidizing gas flowing through the gap is Since it is discharged without being used for the power generation reaction of the fuel cell, the power generation efficiency of the fuel cell decreases. However, according to this embodiment, there is no gap in which the oxidizing gas flows without passing through either the first porous body portion 350b or the second porous body portion 350c in the flow direction of the oxidizing gas. The power generation efficiency of the battery 10 is unlikely to decrease.

  Further, the first porous body portion 350b and the second porous body 350b are separated from each other by a dividing line 350a in which the angle formed by the direction in which the oxidizing gas flows is smaller than the angle formed by the direction in which the oxidizing gas flows and the diagonal line of the porous body 350. By dividing the porous body 350c, the seal length between the side 320d of the opening 320 and the side 350k of the second porous body 350c is set to the same length as the length of the porous body 350 in the oxidizing gas flow direction. Yes, that is, the seal length can be the longest. As a result, the gap between the porous body and the opening can be minimized, and the power generation efficiency of the fuel cell can be increased.

  Further, by dividing the porous body 350 obliquely with respect to the direction in which the oxidizing gas flows, for example, the first porous body portion 350b and the second porous body portion are generated by heat generated by an electrochemical reaction of the fuel cell 10. Even if 350c expands, it can be absorbed by moving in the direction of the dividing line, so that a gap is hardly formed.

  When the porous body 350 is divided into two, it is preferable to divide the first porous body portion 350b and the second porous body portion 350c into the same shape. For example, in FIG. 3, by dividing the first porous body portion 350b and the second porous body portion 350c into the same shape, the right and left ventilation resistances can be balanced, so the power generation efficiency of the fuel cell 10 is improved. Can do well.

  With reference to FIG. 4, the relationship between the size of the gap between the porous body 350 and the opening 320, the angle between the dividing line dividing the porous body 350 and the direction in which the oxidizing gas flows will be described. FIG. 4 is an explanatory diagram showing the relationship between the size of the gap between the porous body 350 and the opening 320, the angle between the dividing line 350a dividing the porous body 350 and the flow direction of the oxidizing gas. In FIG. 4, only the opening 320 and the inside of the opening 320 are drawn.

  In the case where the porous body 350 is disposed in the opening 320 without being divided, for example, the porous body 350 is disposed in the opening 320 such that the side 320b and the side 320c are in contact with each other. At this time, a gap of length x1 is generated between the porous body 350 and the side 320d of the opening 320. On the other hand, a gap having a length y1 is generated between the porous body 350 and the side 320a of the opening 320.

  When the first porous body portion 350b and the second porous body portion 350c obtained by dividing the porous body 350 by a dividing line 350a that forms an angle θ with the gas flow direction are arranged, for example, the second porous body portion 350c is arranged. Are arranged such that the side 350k is in contact with the side 320d and the base 350i is in contact with the side 320b, and the state in which the side 350f of the first porous body 350b is in contact with the side 320c is maintained. The part 350b is arranged.

If the value of the length y1 of the gap between the porous body 350 and the side 320a of the opening 320 is larger than the value indicated by A = x1 / tan θ, the base 350d and the side 320a are not in contact with each other. The first porous body portion 350b can be arranged so that the portion 350g and the divided portion 350j are in contact with each other. On the other hand, when the value of the length y1 of the gap between the porous body 350 and the side 320a of the opening 320 is smaller than the value A, the first porous body is in contact with the divided portion 350g and the divided portion 350j. When the body part 350b is disposed, the bottom side 350d protrudes upward from the side 320a in the drawing. That is, if the first porous body portion 350b is arranged so that the bottom side 350d does not protrude from the side 320a, a gap is generated between the divided portion 350g and the divided portion 350j.

  Therefore, y1 ≧ x1 / tan θ must be satisfied in a state where the base 350d and the side 320a are not in contact with each other, and in order that the divided part 350g and the divided part 350j are in contact with each other and no gap is generated. That is, the angle θ between the dividing line 350a and the direction in which the oxidizing gas flows may be an angle satisfying tan θ ≧ x1 / y1, that is, an angle equal to or larger than arctan (x1 / y1). However, the value of θ is 90 degrees or less.

  The dividing line 350 a may coincide with the diagonal line of the porous body 350. By making the dividing line 350a coincide with the diagonal line of the porous body 350, the seal length between the first porous body portion 350b and the opening portion 320 and the seal length between the second porous body portion 350c and the opening portion 320 are set to be porous. The length is the same as 350 in the gas flow direction, and the seal length can be maximized. As a result, the gap between the porous body and the opening can be minimized, and the power generation efficiency of the fuel cell can be improved.

  Furthermore, by making the dividing line 350a coincide with the diagonal line of the porous body 350, the tolerance for the length of the gap between the opening 320 and the porous body 350 in the direction perpendicular to the gas flow direction can be increased. That is, when the length of the gap between the opening 320 and the porous body 350 is equal to or greater than a predetermined length in the direction perpendicular to the gas flow direction, the first porous body 350b and the second porous body 350c are Regardless of the arrangement, a gap in the gas flow direction is generated somewhere. However, by making the dividing line 350a coincide with the diagonal line of the porous body 350, there is no gap in the gas flow direction with respect to the length of the gap between the opening and the porous body in the direction perpendicular to the gas flow direction. The limit value can be increased.

  Here, when the porous body 350 is divided by the dividing line 350a that coincides with the diagonal line, if y1 ≧ x1 / tan θ is not satisfied, the length x1 of the gap between the side 350k and the side 320d should be reduced. It is necessary to increase the gap y1 between the bottom 350d and the side 320a. Here, once the porous body 350 and the opening 320 are formed, reducing the length x1 of the gap between the side 350k and the side 320d may increase the porous 350 or reduce the opening 320. It is necessary and difficult. On the other hand, increasing the gap y1 between the bottom side 350d and the side 320a is, for example, cutting the porous body 350 to reduce the size of the direction in which the oxidizing gas flows, or cutting the opening 320 and flowing the oxidizing gas. It is easy to increase the size of.

  As described above, according to the present embodiment, the porous body 350 including the first porous body portion 350b and the second porous body portion 350c that are obliquely divided with respect to the direction in which the oxidizing gas flows is provided. Therefore, the first porous body portion 350b and the second porous body portion 350c can be arranged so that no gap is generated in the direction in which the oxidizing gas flows. As a result, a sealing member for preventing and suppressing the gap flow of the oxidizing gas becomes unnecessary. Further, since no gap flow of the oxidizing gas is generated, it is possible to prevent or suppress a decrease in the efficiency of the fuel cell.

(Modification)
As shown in FIG. 5, the angle between the porous body 350 and the direction in which the oxidizing gas flows is divided by a dividing line 350t that is larger than the angle between the direction in which the oxidizing gas flows and the diagonal line of the porous body 350. May be. FIG. 5 shows an example in which the porous body 350 is divided by a dividing line 350t in which the angle between the direction in which the oxidizing gas flows and the angle between the direction in which the oxidizing gas flows and the diagonal line of the porous body 350 is larger. It is explanatory drawing which shows.

  In the embodiment shown in FIG. 5, the porous body 350 has a first dividing line 350t in which the angle formed by the direction in which the oxidizing gas flows is larger than the angle formed by the direction in which the oxidizing gas flows and the diagonal line of the porous body 350. It is divided into three porous body portions 350m and a fourth porous body portion 350n. Also in the embodiment shown in FIG. 5, the oxidizing gas always has the third porous body portion 350 m and the fourth porous body portion on the path from the oxidizing gas supply manifold forming hole 302 to the oxidizing gas discharge manifold forming hole 304. It passes through at least one of 350n and does not pass through only the gap. Accordingly, the gap in which the oxidizing gas flows without passing through either the third porous body portion 350m or the fourth porous body portion 350n with respect to the flow direction of the oxidizing gas does not occur, and the power generation efficiency of the fuel cell 10 is reduced. Hateful.

  In this embodiment, the case of dividing the porous body 350 through which the oxidizing gas flows has been described, but it goes without saying that the gap flow of the fuel gas can be suppressed by dividing the porous body 351 through which the fuel gas flows.

  In the present embodiment, the case where the porous body 350 is divided into two has been described. However, for example, the porous body 350 may be divided into three as shown in FIG. FIG. 6 is an explanatory diagram showing an example in which the porous body 350 is divided into three porous body portions. In the embodiment shown in FIG. 6, the second porous body portion 350c is further divided by a dividing line 350q to divide the porous body 350 into a fifth porous body portion 350r and a sixth porous body portion 350s. Divided into three. Even when the porous body 350 is divided into three parts, the first porous body part 350b, the fifth porous body part 350r, and the sixth porous body part 350s are formed so that no gap is generated in the direction in which the oxidizing gas flows. Can be placed. Therefore, the gap flow of the oxidizing gas can be prevented and suppressed. As a result, the power generation efficiency of the fuel cell 10 can be hardly lowered. The porous body 350 may be divided into four or more porous body portions. The degree of freedom of arrangement of the porous body portion is increased, and the gap flow of the oxidizing gas can be easily suppressed.

  In the case of dividing the porous body 350 into three, the dividing line 350a and the dividing line 350q may be symmetric with respect to the flowing direction of the oxidizing gas. For example, if the first porous body portion 350b and the sixth porous body portion 350s are arranged so that the positions (y coordinates) in the oxidizing gas flow direction are the same, the first porous body portion 350b and the fifth porous body portion 350s Since the length of the portion in contact with the porous body portion 350r and the length of the portion in contact with the fifth porous body portion 350r and the sixth porous body portion 350s can be made the same, for example, in FIG. Can be. As a result, the left and right electrochemical reaction can be balanced, and the power generation efficiency of the fuel cell can be improved.

  When the porous body 350 is divided into three, the symmetry axis of the dividing line 350a and the dividing line 350q may pass through the center line AA of the porous body 350. For example, in FIG. 6, if the porous body 350 is divided so that the symmetry axis of the dividing line 350 a and the dividing line 350 q passes through the center line AA of the porous body 350, the flow of the oxidizing gas is more balanced on the left and right. Therefore, the right and left balance can be further improved with respect to the ventilation resistance. As a result, the left and right balance can be achieved for the electrochemical reaction, so that the power generation efficiency of the fuel cell can be improved.

  In this embodiment, nothing is provided in the opening 320 on the side perpendicular to the direction in which the oxidizing gas flows. However, as shown in FIG. 7, the first porous body portion 350b and the second porous body portion 350c are provided. A spring portion 322 may be provided for pressing the frame against the frame 300. FIG. 7 is an explanatory view showing an embodiment provided with a spring portion 322 for pressing the first porous body portion 350 b and the second porous body portion 350 c against the opening 320 of the frame 300. In FIG. 7, springs 322 are provided on the sides 320a and 320b of the opening 320 of the frame 300, which are sides perpendicular to the direction in which the oxidizing gas flows. As the spring part 322, for example, a leaf spring can be used.

  The first porous body portion 350b is pressed in the direction of the side 320c of the opening 320 by the force pressed from the spring portion 322 and the vertical drag from the second porous body portion 350c. Therefore, the side 350f and the side 320c are in close contact with each other, and no gap is generated between the side 350f and the side 320c. The second porous body portion 350c is pressed in the direction of the side 320d of the opening 320 by the force pressed from the spring portion 322 and the vertical drag from the first porous body portion 350b. Therefore, the side 350k and the side 320d are in close contact with each other, and no gap is generated between the side 350k and the side 320d. Further, the first porous body portion 350b and the second porous body portion 350c are pressed against each other by a normal force. Therefore, the divided part 350g and the divided part 350j are in close contact with each other, and no gap is generated between the divided part 350g and the divided part 350j. That is, on the path from the oxidizing gas supply manifold forming hole 302 to the oxidizing gas discharge manifold forming hole 304, one or both of the first porous body part 350b and the second porous body part 350c are always passed, and only the gap is passed. Never go through.

  The spring part 322 is provided so as to push the bottom 350e which is the longer one of the two bottoms 350d and 350e of the first porous body 350b, which is a side perpendicular to the gas flow direction. . Thereby, the division part 350g and the division part 350j can be pressed against each other. In this modification, the spring portion 322 is used. However, for example, it may be a protrusion for positioning the first porous body portion 350b and the second porous body portion 350c. By providing the protrusions, for example, the first porous body portion 350b and the second porous body portion 350c can be easily positioned.

  In the description of the examples, the manufacturing method of the first porous body portion 350b and the second porous body portion 350c has not been described. It is preferable that the body 350 is manufactured after being divided. In the case where the first porous body portion 350b and the second porous body portion 350c are manufactured separately, for example, the angle formed by the dividing portion 350g of the first porous body portion 350b and the direction in which the oxidizing gas flows is It is difficult to make the angle formed by the dividing portion 350j of the second porous body portion 350c and the direction in which the oxidizing gas flows the same. If the angles cannot be made completely the same, for example, it is difficult to bring the divided portion 350g of the first porous body portion 350b into close contact with the divided portion 350j of the second porous body portion 350c. That is, a gap is formed between the divided part 350g of the first porous body part 350b and the divided part 350j of the second porous body part 350c, and the amount of oxidizing gas flowing through the porous body by flowing an oxidizing gas through the gap, That is, the amount of oxidizing gas used for the cell reaction decreases, and the power generation efficiency of the fuel cell decreases.

  The embodiments of the present invention have been described above based on some examples. However, the above-described embodiments of the present invention are for facilitating the understanding of the present invention and limit the present invention. It is not a thing. The present invention can be changed and improved without departing from the spirit and scope of the claims, and it is needless to say that the present invention includes equivalents thereof.

The perspective view which shows typically the external appearance of the fuel cell which concerns on the Example of this invention. Explanatory drawing which shows typically the cross section which cut the fuel cell shown in FIG. 1 in the surface parallel to yz plane. The top view which shows a membrane electrode assembly part typically. Explanatory drawing which shows the relationship between the magnitude | size of the clearance gap between a porous body and an opening part, the angle which the dividing line which divides | segments a porous body, and the flow direction of oxidizing gas make. Explanatory drawing which shows typically the Example which changed the position of the dividing line which cuts the porous body shown in FIG. The figure explaining the Example in the case of dividing | segmenting a porous body into three porous body parts. Explanatory drawing which shows an Example provided with the spring part for pressing a porous body part to the opening part of a flame | frame.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fuel cell 20 ... Separator part 30 ... Membrane electrode assembly part 40 ... Membrane electrode assembly 102 ... Oxidation gas supply manifold 104 ... Oxidation gas discharge manifold 106 ... Fuel gas supply manifold 108 ... Fuel gas discharge manifold 110 ... Cooling water supply Manifold 112 ... Cooling water discharge manifold 200 ... Intermediate plate 202 ... Oxidation gas supply manifold formation hole 204 ... Oxidation gas discharge manifold formation hole 216 ... Oxidation gas supply communication part 218 ... Oxidation gas discharge communication part 220 ... Anode side plate 240 ... Cathode side plate 256 ... Oxidizing gas introduction hole 258 ... Oxidizing gas outlet hole 300 ... Frame 302 ... Oxidizing gas supply manifold forming hole 304 ... Oxidizing gas discharge manifold forming hole 306 ... Fuel gas supply manifold forming hole 08 ... Fuel gas discharge manifold forming hole 310 ... Cooling water supply manifold forming hole 312 ... Cooling water discharge manifold forming hole 320 ... Opening 320a ... Side 320b ... Side 320c ... Side 320d ... Side 322 ... Spring part 350 ... Porous Body 350a ... Dividing line 350b ... 1st porous body part 350c ... 2nd porous body part 351 ... Porous body 350d ... Bottom 350e ... Bottom 350f ... Side 350g ... Dividing part 350h ... Bottom 350i ... Bottom 350j ... Dividing part 350k ... side 350m ... third porous body 350n ... fourth porous body 350q ... partition line 350r ... fifth porous part 350s ... sixth porous part 350t ... partition line 400 ... electrolyte membrane 420 ... catalyst Layer 421 ... Catalyst layer

Claims (10)

A fuel cell,
A membrane electrode assembly;
A porous body that diffuses a gas flowing in a predetermined direction adjacent to the membrane electrode assembly, and includes a first porous body portion and a second porous body portion that are obliquely divided with respect to the gas flowing direction. A porous body,
A frame having an opening for internally supporting the membrane electrode assembly and the porous body;
A fuel cell comprising: The fuel cell according to claim 1, wherein
The fuel cell, wherein a shape of the porous body and a shape of the opening are rectangular. The fuel cell according to claim 2, wherein
The first porous body part and the second porous body part are:
One side of the first porous body portion is in contact with a first side of the two sides of the opening parallel to the gas flow direction,
One side of the second porous body portion is in contact with a second side different from the first side of the two sides of the opening parallel to the gas flow direction,
The first porous body part and the second porous body part are in contact with each other,
A fuel cell disposed in the opening. The fuel cell according to claim 3, wherein
The angle formed by the gas flow direction and the dividing line dividing the porous body is smaller than the angle formed by the gas flow direction and the diagonal line of the porous body,
And the shape of the said 1st porous body part and the shape of the said 2nd porous body part are trapezoid, The fuel cell. The fuel cell according to claim 3, wherein
The fuel cell, wherein the dividing line coincides with a diagonal line of the porous body. The fuel cell according to claim 3 or 4,
The angle between the gas flow direction and the dividing line is such that the value of the tangent to the angle is the length of the gap between the porous body and the opening in the direction perpendicular to the gas flow direction. A fuel cell having an angle greater than or equal to a value divided by a length of a gap between the porous body and the opening in a direction parallel to a gas flow direction. The fuel cell according to any one of claims 3 to 5, wherein
The length of the gap between the porous body and the opening in a direction parallel to the gas flow direction is the length of the gap between the porous body and the opening in a direction perpendicular to the gas flow direction. The fuel cell is formed to have a size equal to or greater than a value obtained by dividing the value by the tangent of the angle between the gas flow direction and the dividing line. The fuel cell according to claim 1 or 2, further comprising:
The fuel cell, wherein the second porous body portion is divided into a plurality of porous body portions. The fuel cell according to any one of claims 1 to 8, further comprising:
The frame is a fuel cell, comprising positioning means for determining a position of the divided porous body portion. The fuel cell according to claim 9, wherein
The positioning means is provided on one side of the frame, which is perpendicular to the gas flow direction in the divided porous body portion, presses the first porous body portion, and the first porous body portion A fuel cell in which a porous body portion different from the body portion is pressed against one side of the frame and parallel to the gas flow direction.

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