JP6642373B2 - Fuel cell - Google Patents

Description

  The present invention relates to a fuel cell.

  A fuel cell having a configuration in which a fuel cell stack including a stacked body of a plurality of single cells is housed in a case is disclosed (Patent Document 1).

JP 2016-12408 A

  When the fuel cell described in Patent Literature 1 is used by being mounted on a vehicle, for example, a reaction gas (eg, hydrogen gas) supplied to the fuel cell stack abnormally burns in the fuel cell stack due to a collision of the vehicle, and the combustion thereof occurs. As a result, the gas or reaction gas leaked out of the fuel cell may cause a problem that the pressure in the case becomes excessively high. If the pressure in the case is excessively increased, the entire fuel cell including the fuel cell stack may be damaged. The above problem is not limited to fuel cells mounted on vehicles, but is common to fuel cells having a configuration in which a fuel cell stack is housed in a case, such as a fuel cell fixedly arranged in a building. Therefore, in a fuel cell having a configuration in which a fuel cell stack is housed in a case, a technique for suppressing an increase in pressure inside the case is desired.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following embodiments.

  (1) According to one embodiment of the present invention, a fuel cell is provided. The fuel cell includes a stacked body including a plurality of stacked unit cells; a first wall, and a second wall intersecting with the first wall and having higher rigidity than the first wall. A case that accommodates the stacked body; and a porous body disposed inside the case at a corner corresponding to an intersection of the first wall and the second wall. .

  According to the fuel cell of this aspect, the case has the first wall portion and the second wall portion that intersects the first wall portion and has higher rigidity than the first wall portion. When the gas generated by abnormal combustion leaks from the laminate and the pressure inside the case rises excessively, the first wall portion is intentionally destroyed near the intersection to release the pressure inside the case. In addition, an increase in pressure inside the case can be suppressed. Even when the first wall portion is broken in this way, since the porous body portion is disposed at the corner corresponding to the intersection, the pressure inside the case is reduced while the porous body portion is released. A member or the like having a diameter larger than the hole can be prevented from entering the case.

  The present invention can be realized in various forms. For example, the present invention can be realized in a form of a fuel cell system including a fuel cell, a vehicle including the fuel cell system, or the like.

FIG. 1 is a perspective view illustrating a schematic configuration of a fuel cell according to an embodiment of the present invention. FIG. 2 is a sectional view showing a 2-2 section shown in FIG. 1. It is an enlarged view of the area | region shown in FIG. FIG. 4 is an enlarged perspective view showing an opening of a case in the fuel cell when abnormal combustion occurs. FIG. 4 is an enlarged view showing a region when abnormal combustion occurs.

A. Embodiment:
A1. Fuel cell configuration:
FIG. 1 is a perspective view showing a schematic configuration of a fuel cell 100 according to one embodiment of the present invention. FIG. 2 is a sectional view showing a 2-2 section shown in FIG. 1 and 2, the Z axis is set parallel to the vertical direction, and the X axis and Y axis are set parallel to the horizontal direction. The + Z direction corresponds to vertically upward and the -Z direction corresponds to vertically downward. Note that the X, Y, and Z axes in FIG. 1 correspond to the X, Y, and Z axes in other drawings.

  As shown in FIGS. 1 and 2, the fuel cell 100 includes a fuel cell stack 90, a case 40, and a plurality of bolts 80. As shown in FIG. 1, the fuel cell 100 has a configuration in which a fuel cell stack 90 is accommodated in a case 40. In FIG. 1, as the case 40, the illustration of the case lid 40b shown in FIG. 2 is omitted, and only the case main body 40a is shown. In FIG. 2, for convenience of explanation, the porous body portion 50 shown in FIG. 1 is represented by a broken line and hatched as in FIG.

  As shown in FIG. 2, the fuel cell stack 90 includes the stacked body 10, a first end plate 20a, a second end plate 20b, and a pressure plate 30. The stacked body 10 is configured to include a plurality of unit cells 11 stacked in a stacking direction (hereinafter, simply referred to as a “stacking direction”) that is a direction substantially parallel to the X axis. Specifically, the multilayer body 10 includes a plurality of single cells 11, a pair of terminal plates 12, and a pair of insulators 13.

  In this embodiment, each single cell 11 is a solid polymer fuel cell, and uses a reaction gas supplied to an anode-side catalyst electrode layer and a cathode-side catalyst electrode layer provided with a solid polymer electrolyte membrane interposed therebetween. Electric power is generated by the electrochemical reaction. In the present embodiment, the reaction gas (fuel gas) on the anode side is hydrogen gas. The reaction gas (oxidant gas) on the cathode side is air. In the present embodiment, the catalyst electrode layer of each electrode is configured to include carbon particles supporting platinum (Pt) as a catalyst and an electrolyte.

  In each single cell 11, a gas diffusion layer formed of a porous body is disposed outside the catalyst electrode layer of each electrode. As the porous body, for example, a carbon porous body such as carbon paper and carbon cloth, and a metal porous body such as a metal mesh and a foamed metal are used. In addition, a separator having conductivity is arranged outside the gas diffusion layer of each electrode. Inside the fuel cell stack 90, a plurality of manifolds for supplying a reaction gas to each unit cell 11, discharging off-gas from each unit cell 11, and supplying and discharging a cooling medium to each unit cell 11 are provided. Are formed substantially parallel to the laminating direction.

  The pair of terminal plates 12 are made of a plate-shaped conductive member and function as integrated electrodes. Each terminal plate 12 is arranged adjacent to the outer surface of each outermost unit cell 11 in the stacking direction of the stacked body of the plurality of unit cells 11. Specifically, the terminal plate 12 on the + X direction side of the fuel cell stack 90 is disposed outside (+ X direction) in the stacking direction of the unit cells 11 located at the end in the + X direction of the stacked body of the plurality of unit cells 11. ing. The terminal plate 12 on the −X direction side of the fuel cell stack 90 is arranged outside (−X direction) in the stacking direction of the unit cells 11 located at the −X direction end of the stacked body of the plurality of unit cells 11. .

  The pair of insulators 13 is made of a plate-shaped insulating member, and electrically connects between one terminal plate 12 and the first end plate 20a and between the other terminal plate 12 and the second end plate 20b. Insulation. Each insulator 13 is disposed adjacent to an outer surface of each terminal plate 12 in the stacking direction. More specifically, the insulator 13 on the + X direction side of the fuel cell stack 90 is arranged such that one of the two surfaces in the stacking direction of the terminal plate 12 on the + X direction side (the surface in the + X direction) is in the stacking direction. It is arranged outside (+ X direction). The insulator 13 on the −X direction side of the fuel cell stack 90 is located outside (in the −X direction) of one of the two surfaces in the stacking direction of the terminal plate 12 on the −X direction side (outside in the stacking direction). -X direction).

  The first end plate 20a is located outside (in the + X direction) in the stacking direction with respect to one of the two surfaces (the surface in the + X direction) of the stack 10 in the stacking direction. Specifically, the first end plate 20a is arranged outside (the + X direction) of the insulator 13 located at the end of the laminate 10 in the + X direction in the lamination direction. The first end plate 20a is a plate-shaped member. The first end plate 20a, together with a later-described second end plate 20b and a later-described pressure plate 30, sandwiches the laminated body 10 with a predetermined compressive force, and holds the laminated state of the laminated body 10. In the present embodiment, the first end plate 20a is formed of aluminum. In addition, instead of aluminum, it may be formed of a metal or alloy such as steel or titanium. The planar shape (contour shape when viewed in the −X direction) of the first end plate 20a is substantially rectangular.

  The first end plate 20a has a plurality of through holes (not shown) that penetrate in the thickness direction (X-axis direction). The plurality of through holes communicate with a plurality of manifolds (not shown) formed inside the multilayer body 10 to supply the reaction gas and the cooling medium to the multilayer body 10 and to discharge the off gas and the cooling medium from the multilayer body 10. Used for

  The second end plate 20b is located on the outer side in the stacking direction with respect to the surface (−X direction) opposite to the side on which the first end plate 20a is arranged, of the two surfaces of the stack 10 in the stacking direction. (-X direction). Specifically, the insulator 13 located at the end of the laminate 10 in the −X direction is disposed outside (−X direction) in the laminating direction. The second end plate 20b has the same shape as the first end plate 20a, and is made of the same material as the first end plate 20a.

  The pressure plate 30 is disposed adjacent to one of the two surfaces of the second end plate 20b in the stacking direction (the surface in the -X direction) outside (the -X direction) in the stacking direction. I have. The pressure plate 30 has the same shape as the first end plate 20a, and is made of the same material as the first end plate 20a. The pressure plate 30 is joined to the case 40 by a plurality of bolts 80. A fastening load is applied to the fuel cell stack 90 in a state where the pressure plate 30 and the case 40 are joined.

  As shown in FIG. 2, the case 40 includes a case main body 40a and a case lid 40b. As shown in FIGS. 1 and 2, the case body 40 a has a bottomed cylindrical external shape in which an opening is formed at an end on the + X direction side and an end on the opposite side (−X direction side) is closed. Having. As shown in FIG. 2, the case cover 40b is fastened to the case body 40a so as to cover the opening of the case body 40a. More specifically, the case body 40a has a flange around the opening of the case body 40a, extending along the direction from the center of the opening toward the edge of the opening. The flange portion is in contact with the surface of the case cover 40b in the −X direction, and is connected to the peripheral edge of the case cover 40b by a plurality of bolts 80. The case 40 is excellent in waterproofness, dustproofness, and impact resistance, and is made of aluminum in the present embodiment.

  As shown in FIG. 1, the case main body 40a is formed from the above-described flange and a plurality of walls. The above-described plurality of wall portions includes a first wall portion 41B, a second wall portion 41R, a third wall portion 41E, a fourth wall portion 41L, and a fifth wall portion 41T.

  The first wall 41B intersects the second wall 41R and the fourth wall 41L, respectively, and forms a bottom wall of the case body 40a. The second wall 41R intersects the first wall 41B, the third wall 41E, and the fifth wall 41T, respectively, and forms the right wall of the case body 40a when viewed in the −X direction. The third wall portion 41E intersects the first wall portion 41B, the second wall portion 41R, the fourth wall portion 41L, and the fifth wall portion 41T, respectively, and is a rear wall of the case body 40a when viewed in the −X direction. Form a part. The fourth wall portion 41L intersects the first wall portion 41B, the third wall portion 41E, and the fifth wall portion 41T, respectively, and forms a left side wall portion of the case main body portion 40a when viewed in the −X direction. The fifth wall 41T intersects the second wall 41R, the third wall 41E, and the fourth wall 41L, respectively, and forms a ceiling wall of the case body 40a. As shown in FIG. 1, a case 40 (case body) defined by a first wall portion 41B, a second wall portion 41R, a third wall portion 41E, a fourth wall portion 41L, and a fifth wall portion 41T. The fuel cell stack 90 is arranged in the internal space of the part 40a).

  As shown in FIG. 1, a porous body 50 is disposed at each of two corners 42a and 42b inside the case body 40a. The corner 42a is an area corresponding to the intersection of the first wall 41B and the fourth wall 41L. The corner 42b is a region corresponding to the intersection of the first wall 41B and the second wall 41R. Here, the “region corresponding to the intersection between the wall portion and the wall portion” is a region near the intersection portion between the wall portion and the wall portion, and means a region within a predetermined distance from each wall portion. I do. Therefore, a part of the corner may be in contact with at least one of the walls, or may be separated from at least one of the walls within a predetermined distance.

  FIG. 3 is an enlarged view of the region Ar1 shown in FIG. The region Ar1 is a region including the corner 42b near the opening of the case body 40a. 3, illustration of the fuel cell stack 90 housed in the case 40 is omitted. As shown in FIGS. 2 and 3, the porous body portion 50 has a triangular prism shape and is arranged along the stacking direction from the opening of the case body 40a to the third wall 41E. I have. As shown in FIGS. 2 and 3, the porous body portion 50 is disposed in the corner portion 42 b inside the case 40 in contact with the first wall portion 41B and the second wall portion 41R. The cross-sectional shapes of a plane parallel to the XY plane and a plane parallel to the YZ plane of the porous body 50 are substantially rectangular. The porous body 50 has a mesh shape in which a large number of holes are formed. 2 and 3 schematically show the holes formed in the porous body 50. The rigidity of the porous body portion 50 is such that abnormal combustion of the reaction gas occurs in the fuel cell stack 90 (hereinafter, referred to as “abnormal combustion occurrence”), and the gas and the reaction gas generated by the abnormal combustion are generated by the fuel cell stack 90. The rigidity is set to such a degree as not to be damaged when the pressure leaks from the case 90 and the pressure in the case 40 rises sharply. Such rigidity control can be realized, for example, by adjusting the size, number, shape, and the like of the holes formed in the porous body 50. In the present embodiment, the porous body portion 50 is formed by combining a mesh-shaped punching member. Note that, in place of the punching member, any other member such as a metal mesh having a hole through which a reaction gas can pass may be used. Note that the configuration in the vicinity of the corner 42a is the same, and a description thereof will be omitted.

  As shown in FIG. 3, the thickness t1 (length in the Z-axis direction) of the first wall portion 41B is smaller than the thickness t2 (length in the Y-axis direction) of the second wall portion 41R. In the present embodiment, the thicknesses t1 and t2 mean the average thicknesses of the respective wall portions 41B and 41R. As described above, since each wall (case 40) is formed of the same member (aluminum), there is a rigidity difference between the first wall 41B and the second wall 41R due to the thickness. . That is, the second wall 41R has higher rigidity than the first wall 41B. Although not shown, in the present embodiment, the thickness of each of the third wall portion 41E, the fourth wall portion 41L, and the fifth wall portion 41T is the same as the thickness t2 of the second wall portion 41R.

A2. State of fuel cell 100 when abnormal combustion occurs:
FIG. 4 is an enlarged perspective view showing an opening of the case 40 in the fuel cell 100 when abnormal combustion occurs. Abnormal combustion occurs in the fuel cell stack 90 accommodated in the case 40, and the gas and reaction gas generated by the abnormal combustion leak from the fuel cell stack 90, and the pressure in the case 40 increases. At this time, the weaker first wall portion 41B having low rigidity is broken. In particular, the first wall portion 41B is easily broken at a connection portion with the second wall portion 41R and the fourth wall portion 41L having higher rigidity than the first wall portion 41B. Therefore, the first wall 41B is broken at the corners 42a and 42b, and the gap 70 is formed.

  FIG. 5 is an enlarged view showing the region Ar1 when abnormal combustion occurs. 5, illustration of the fuel cell stack 90 housed in the case 40 is omitted as in FIG. As shown in FIG. 5, the end of the first wall 41 </ b> B in the −Y direction is broken, so that a gap 70 is formed in the case 40. The void 70 is closed by the porous body 50. However, since a large number of holes are formed in the porous body 50, the gas (hydrogen gas or the like) in the case 40 is discharged to the outside of the fuel cell 100 through the holes of the porous body 50 and the gap 70. Is done. Therefore, an increase in the pressure in the case 40 is suppressed. Further, as described above, the porous body 50 is disposed at the corner 42b, that is, is disposed so as to cover the void 70 formed at the corner 42b. An object having a diameter larger than the diameter can be prevented from entering the case 40 from outside. Such objects include various screws, wire harnesses, fingers of maintenance workers, and the like. Similarly, even if the first wall portion 41B is broken near the corner 42a, an increase in the pressure in the case 40 can be suppressed, and the entry of foreign matter into the case 40 can be suppressed.

  According to the fuel cell 100 having the above configuration, the case 40 includes the first wall portion 41B, the second wall portion 41R that intersects with the first wall portion 41B and has a higher rigidity than the first wall portion 41B, and the fourth wall portion 41R. With the wall portion 41L, when gas generated by abnormal combustion of the reaction gas in the laminate 10 leaks from the laminate 10 and the pressure inside the case 40 rises excessively, the first wall near the intersection is formed. The pressure in the case 40 is released by intentionally destroying the portion 41 </ b> B, so that an increase in the pressure in the case 40 can be suppressed. Even when the first wall portion 41B is broken in this way, since the porous body portions 50 are arranged at the corner portions 42a and 42b corresponding to the intersections, the pressure in the case 40 is released. In addition, it is possible to prevent a member or the like having a larger diameter than the hole of the porous body portion 50 from entering the case 40.

B. Modification:
B1. Modification 1
In the above embodiment, the difference in rigidity between the first wall portion 41B, the second wall portion 41R, and the fourth wall portion 41L is provided by an average difference in thickness, but the present invention is not limited to this. For example, the corners 42a and 42b of the first wall 41B are provided with cutouts at predetermined intervals along the stacking direction, and the corners 42a of the fourth wall 41L and the corners 42b of the second wall 41R are provided. By not providing such a notch, a difference in rigidity between the first wall portion 41B and the second wall portion 41R and the fourth wall portion 41L may be provided. In this case, by arranging the porous body portion 50 at the location where the notch is formed in the first wall portion 41B, the same effect as in the above-described embodiment can be obtained. Also, ribs are provided on the inner side surfaces of the corner 42a of the fourth wall 41L and the corner 42b of the second wall 41R, and the rib is not provided on the first wall 41B. The rigidity difference between the second wall portion 41R and the fourth wall portion 41L may be provided.

  Furthermore, by making the material of the first wall 41B different from the material of the second wall 41R and the fourth wall 41L, the first wall 41B, the second wall 41R and the fourth wall 41L are formed. May be provided. For example, the first wall 41B may be formed of aluminum, the second wall 41R and the fourth wall 41L may be formed of iron, or the first wall 41B, the second wall 41R, and the fourth wall may be formed. 41L may be formed of the same metal member, and then the second wall portion 41R and the fourth wall portion 41L may be made of an alloy with another metal so as to have higher rigidity than the first wall portion 41B, By quenching the second wall portion 41R and the fourth wall portion 41L, the rigidity may be higher than that of the first wall portion 41B. Even in such a configuration, the same effect as in the above embodiment can be obtained.

B2. Modification Example 2:
In the above embodiment, the porous body portion 50 is arranged along the stacking direction from the opening of the case main body portion 40a to the third wall portion 41E, but the present invention is not limited to this. For example,
The length of the porous body 50 in the stacking direction (X-axis direction) may be shortened, and such porous bodies 50 may be arranged at predetermined intervals along the stacking direction. Even in such a configuration, the same effect as in the above embodiment can be obtained.

B3. Modification 3:
In the above embodiment, the cross-sectional shape of the porous body portion 50 by a plane parallel to the horizontal plane is substantially rectangular, but may be an arbitrary shape such as a trapezoid or a circle instead of the rectangle. Even in such a configuration, the same effect as in the above embodiment can be obtained.

B4. Modification 4:
In the above embodiment, the porous body portion 50 has a triangular prism shape, but may have a cylindrical shape instead of the triangular prism shape, or a plate shape instead of the column shape. For example, it may be configured as an angle member having an L-shaped cross section provided with a large number of holes. Even in such a configuration, the same effect as in the above embodiment can be obtained.

B5. Modification 5:
In the above embodiment, the thickness of each of the third wall portion 41E, the fourth wall portion 41L, and the fifth wall portion 41T is the same as the thickness t2 of the second wall portion 41R, but the present invention is not limited to this. . For example, the thickness of the fifth wall portion 41T may be set to be the same as the thickness t1 of the first wall portion 41B. In this case, in the case 40, the corner corresponding to the intersection between the fifth wall 41T and the second wall 41R, and the corner corresponding to the intersection between the fifth wall 41T and the fourth wall 41L. By arranging the porous body portions 50 in each case, the same effect as in the present embodiment can be obtained.

B6. Modification 6:
In the above embodiment, the first end plate 20a is configured to be housed in the case 40 (the case body 40a), but the present invention is not limited to this. For example, the case lid 40b may be omitted, and the first end plate 20a may have a function as the case lid 40b. Even in such a configuration, the same effect as in the present embodiment can be obtained.

  The present invention is not limited to the above-described embodiments and modified examples, and can be realized with various configurations without departing from the spirit thereof. For example, the embodiments corresponding to the technical features in the respective embodiments described in the summary of the invention, the technical features in the modified examples may be used to solve some or all of the above-described problems, or In order to achieve some or all of the effects, replacement and combination can be performed as appropriate. Unless the technical features are described as essential in the present specification, they can be deleted as appropriate.

DESCRIPTION OF SYMBOLS 10 ... Laminated body 11 ... Single cell 12 ... Terminal plate 13 ... Insulator 20a ... First end plate 20b ... Second end plate 30 ... Pressure plate 40 ... Case 40a ... Case body part 40b ... Case lid part 41B ... First Wall part 41E Third wall part 41L Fourth wall part 41R Second wall part 41T Fifth wall part 42a, 42b Corner part 50 Porous body part 70 Void 80 Bolt 90 Fuel cell stack 100 Fuel cell Ar1 area

Claims (1)

A fuel cell,
A stacked body including a plurality of unit cells stacked,
A case that includes a first wall portion, a second wall portion that intersects the first wall portion and has higher rigidity than the first wall portion, and accommodates the stacked body;
Inside the case, a porous body disposed at a corner corresponding to an intersection of the first wall and the second wall;
A fuel cell comprising:

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