JP4783562B2 - Fuel cell stack - Google Patents

Description

  The present invention includes a unit cell in which an electrolyte / electrode structure in which a pair of electrodes are provided on both sides of an electrolyte is sandwiched between separators, and a stacked body in which a plurality of the unit cells are stacked is contained in a box-shaped casing. It relates to a battery stack.

  For example, a polymer electrolyte fuel cell employs an electrolyte membrane (electrolyte) made of a polymer ion exchange membrane. An electrolyte membrane / electrode structure in which an anode side electrode and a cathode side electrode are provided on both sides of the electrolyte membrane includes a unit cell sandwiched between separators, and a plurality of the unit cells are stacked to constitute a fuel cell stack. Has been.

  In this unit cell, a fuel gas, for example, a gas mainly containing hydrogen (hereinafter also referred to as hydrogen-containing gas) is supplied to the anode side electrode, while an oxidant gas, for example, A gas or air mainly containing oxygen (hereinafter also referred to as oxygen-containing gas) is supplied. In the fuel gas supplied to the anode side electrode, hydrogen is ionized on the electrode catalyst and moves to the cathode side electrode side through the electrolyte membrane. Electrons generated during that time are taken out to an external circuit and used as direct current electric energy.

  In the fuel cell stack, it is necessary to detect whether each unit cell has a desired power generation performance. For this reason, the operation | work which detects the cell voltage for every unit cell at the time of electric power generation is normally performed by connecting the cell voltage terminal provided in the separator to the voltage detection apparatus.

  For example, in Patent Document 1, a plurality of cell voltage monitors are attached to a fuel cell stack, and each cell voltage monitor has one housing fixed to the fuel cell stack and one or more terminals held by the housing. One or more terminals of each cell voltage monitor are arranged in a row in the cell stacking direction of the fuel cell stack in parallel with each other in the housing of the cell voltage monitor. The plurality of housings provided one by one are arranged in a staggered manner on the side surface of the fuel cell stack.

JP 2004-79192 A (FIGS. 4 and 5)

  Recently, in addition to a structure in which the end plates are clamped and held between end plates, a structure in which a plurality of unit cells are accommodated in a box-shaped casing has been adopted for the fuel cell stack. However, in the casing, each side surface of the stacked unit cells is covered with a side plate. Therefore, the side plate needs to be devised so that a plurality of cell voltage monitors can be attached to the plurality of unit cells. .

  For example, as shown in FIG. 10, the fuel cell stack 1 includes a stacked body 3 in which a plurality of unit cells 2 are stacked in the direction of arrow X, and the stacked body 3 is accommodated in a casing 4. At least one side plate 5 constituting the casing 4 is formed with a long opening 7 in the stacking direction so as to avoid the cell voltage monitors 6 arranged in a staggered manner in the arrow X direction. However, since the side plate 5 has the long opening 7 in the stacking direction, there is a problem that the rigidity of the side plate 5 itself is remarkably lowered.

  Therefore, for example, as shown in FIG. 11, it is conceivable to form a plurality of staggered openings 9a and 9b in the direction of the arrow X in one side plate 8 corresponding to a cell voltage monitor (not shown). . However, when a plurality of unit cells (not shown) are stacked in the direction of the arrow X, dimensional variations are accumulated as the number of stacked layers increases due to the dimensional tolerance and assembly tolerance of each unit cell.

  For this reason, for example, when unit cells are stacked in the direction of the arrow X1, a relatively large displacement occurs in the unit cell arranged on the tip side in the direction of the arrow X1, and the opening 9a or 9b with respect to the unit cell. A problem is pointed out that a cell voltage monitor (not shown) cannot be installed.

  The present invention solves this type of problem, and provides a fuel cell stack capable of easily and reliably detecting cell voltages of a plurality of stacked unit cells and effectively maintaining the rigidity of the casing itself. The purpose is to provide.

  The present invention includes a unit cell in which an electrolyte / electrode structure in which a pair of electrodes are provided on both sides of an electrolyte is sandwiched between separators, and a stacked body in which a plurality of the unit cells are stacked is contained in a box-shaped casing. It is a battery stack.

In at least one surface of the casing, a plurality of openings corresponding to desired cell voltage terminals are provided along the stacking direction of the unit cells in order to detect a cell voltage for each unit cell or for each unit cell. The plurality of openings are preferably set so that the opening area increases from one end side to the other end side in the stacking direction. When unit cells are sequentially stacked from one end side to the other end side in the stacking direction, dimensional tolerances and assembly tolerances are accumulated in the unit cells on the other end side. For this reason, by setting a large opening area on the other end side in the stacking direction, it is possible to absorb variations in dimensions accumulated in the unit cell and to easily detect the cell voltage of the unit cell. Become.

  Furthermore, the plurality of openings are preferably set so that the opening area increases from the center in the stacking direction toward both ends. Prepare two stacked bodies in which a predetermined number of unit cells are stacked in advance, and when these two stacked bodies form a fuel cell stack by stacking the respective stack start side unit cells, Compared with the unit cells at both ends in the stacking direction, the dimensional variation is accumulated. Therefore, by setting the opening area at both ends in the stacking direction to be large, it is possible to reliably absorb the variation in dimensions accumulated in the unit cell, and to easily detect the cell voltage of the unit cell. it can.

  Furthermore, it is preferable that the other surface of the casing is provided with a plurality of openings corresponding to the cell voltage terminals by shifting positions in the stacking direction from the plurality of openings. This is because the cell voltage can be easily and accurately detected for each unit cell adjacent to each other.

  In the present invention, at least one surface of the casing is provided with a plurality of openings corresponding to desired cell voltage terminals in order to detect a cell voltage for each unit cell or for each of a plurality of unit cells. The rigidity of the casing itself is improved better than the configuration in which the elongated opening that extends is provided.

Moreover, the plurality of openings are set so that the opening area increases from one end side to the other end side in the stacking direction, or the opening area increases from the center side in the stacking direction to both end sides , Variations in dimensions in the stacking direction can be absorbed. As a result, the cell voltage of the unit cell can be easily and accurately detected without being affected by the deviation in the stacking direction of the unit cells.

  FIG. 1 is a partially exploded schematic perspective view of a fuel cell stack 10 according to the first embodiment of the present invention, and FIG. 2 is a partial sectional side view of the fuel cell stack 10.

  As shown in FIG. 1, the fuel cell stack 10 includes a stacked body 14 in which a plurality of unit cells 12 are stacked in the horizontal direction (arrow A direction). A terminal plate 16a, an insulating plate 18 and an end plate 20a are sequentially disposed at one end in the stacking direction (arrow A direction) of the stacked body 14 toward the outside. At the other end in the stacking direction of the stacked body 14, a terminal plate 16b, an insulating spacer member 22 and an end plate 20b are sequentially disposed outward. The fuel cell stack 10 includes a casing 24 including end plates 20a and 20b each having a rectangular shape as end plates.

  As shown in FIGS. 2 and 3, each unit cell 12 includes an electrolyte membrane / electrode structure (electrolyte / electrode structure) 30, and a thin plate-shaped first and second sandwiching the electrolyte membrane / electrode structure 30. Second metal separators 32 and 34 are provided. Instead of the first and second metal separators 32 and 34, for example, a carbon separator may be used.

  Specifically, in the first embodiment, the outer periphery of the first metal separator 32 and / or the second metal separator 34 is positioned on the one end side in the arrow B direction on the outer periphery of the second metal separator 34. A cell voltage terminal 35 for detecting a voltage generated in the electrolyte membrane / electrode structure 30 is integrally formed.

  An oxidant gas supply for supplying an oxidant gas, for example, an oxygen-containing gas, communicates with each other in the arrow A direction at one end edge of the unit cell 12 in the long side direction (the arrow B direction in FIG. 3). A communication hole 36a, a cooling medium supply communication hole 38a for supplying a cooling medium, and a fuel gas discharge communication hole 40b for discharging a fuel gas, for example, a hydrogen-containing gas, are provided.

  The other end edge in the long side direction of the unit cell 12 communicates with each other in the direction of arrow A, and a fuel gas supply communication hole 40a for supplying fuel gas, and a cooling medium discharge communication hole for discharging the cooling medium. 38b and an oxidizing gas discharge communication hole 36b for discharging the oxidizing gas are provided.

  The electrolyte membrane / electrode structure 30 includes, for example, a solid polymer electrolyte membrane 42 in which a perfluorosulfonic acid thin film is impregnated with water, and an anode side electrode 44 and a cathode side electrode 46 that sandwich the solid polymer electrolyte membrane 42. With.

  The anode side electrode 44 and the cathode side electrode 46 are uniformly coated with a gas diffusion layer (not shown) made of carbon paper or the like and porous carbon particles carrying a platinum alloy on the surface thereof. And an electrode catalyst layer (not shown) formed. The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 42.

  A fuel gas flow path 48 that connects the fuel gas supply communication hole 40 a and the fuel gas discharge communication hole 40 b is formed on the surface 32 a of the first metal separator 32 facing the electrolyte membrane / electrode structure 30. The fuel gas channel 48 is constituted by, for example, a plurality of grooves extending in the arrow B direction. On the surface 32b of the first metal separator 32, a cooling medium flow path 50 that connects the cooling medium supply communication hole 38a and the cooling medium discharge communication hole 38b is formed. The cooling medium flow path 50 is configured by a plurality of grooves extending in the arrow B direction.

  The surface 34a of the second metal separator 34 facing the electrolyte membrane / electrode structure 30 is provided with, for example, an oxidant gas flow path 52 composed of a plurality of grooves extending in the direction of arrow B, and this oxidant gas. The flow path 52 communicates with the oxidant gas supply communication hole 36a and the oxidant gas discharge communication hole 36b. A cooling medium flow path 50 is integrally formed on the surface 34 b of the second metal separator 34 so as to overlap the surface 32 b of the first metal separator 32.

  A first seal member 54 is integrally formed on the surfaces 32 a and 32 b of the first metal separator 32 around the outer peripheral edge of the first metal separator 32. The first seal member 54 surrounds the fuel gas supply communication hole 40a, the fuel gas discharge communication hole 40b, and the fuel gas flow path 48 on the surface 32a so as to communicate with each other, and on the surface 32b, the cooling medium supply communication hole 38a, The medium discharge communication hole 38b and the cooling medium flow path 50 are surrounded and communicated with each other.

  A second seal member 56 is integrally formed on the surfaces 34 a and 34 b of the second metal separator 34 around the outer peripheral edge of the second metal separator 34. The second seal member 56 surrounds and communicates the oxidant gas supply communication hole 36a, the oxidant gas discharge communication hole 36b, and the oxidant gas flow path 52 on the surface 34a, while the cooling medium supply communication hole on the surface 34b. 38a, the cooling medium discharge communication hole 38b, and the cooling medium flow path 50 are surrounded and communicated. The second seal member 56 is peeled off from the cell voltage terminal 35, and the cell voltage terminal 35 is exposed to the outside.

  As shown in FIG. 2, a seal 57 is interposed between the first and second seal members 54 and 56 in order to prevent the outer periphery of the solid polymer electrolyte membrane 42 from directly contacting the casing 24. Is done.

  As shown in FIGS. 1 and 2, plate-like terminal portions 58a and 58b protruding in the surface direction are formed at the ends of the terminal plates 16a and 16b. For example, a load such as a traveling motor is connected to the terminal portions 58a and 58b.

  As shown in FIG. 1, the casing 24 includes end plates 20 a and 20 b that are end plates, a plurality of side plates 60 a to 60 d disposed on the side of the laminated body 14, and end portions of the side plates 60 a to 60 d that are close to each other. Angle members (for example, L angles) 62a to 62d that connect the portions, and connecting pins 64a and 64b having different lengths that connect the end plates 20a and 20b and the side plates 60a to 60d, respectively. The side plates 60a to 60d are composed of thin metal plates.

  Two first connection portions 66a and 66b are formed to project from the upper and lower sides of the end plates 20a and 20b, respectively, and one first connection portion 66c and 66d is formed to project from each side of each side. The Holes 67a to 67d are formed through the first connecting portions 66a to 66d. Mount bosses 68a and 68b are formed at the lower ends of the respective sides of the end plates 20a and 20b. The boss portions 68a and 68b are fixed to a mounting portion (not shown) via a bolt or the like, so that the fuel cell stack 10 is mounted on, for example, a vehicle.

  Two second connecting portions 70a and 70b are formed at both ends in the longitudinal direction (arrow A direction) of the side plates 60a and 60c arranged on both sides in the arrow B direction of the laminate 14. Three second connecting portions 72a and 72b are formed at both ends in the longitudinal direction of the side plates 60b and 60d disposed on the upper and lower sides of the laminated body 14, respectively. Holes 71a and 71b are formed in the second connecting portions 70a and 70b, and holes 73a and 73b are formed in the second connecting portions 72a and 72b.

  Between the second connection portions 70a and 70b of the side plates 60a and 60c, first connection portions 66c and 66d on both sides of the end plates 20a and 20b are arranged, and a short connection pin 64a is integrally formed therewith. The side plates 60a and 60c are attached to the end plates 20a and 20b.

  Similarly, the second connecting portions 72a and 72b of the side plates 60b and 60d are alternately arranged with the first connecting portions 66a and 66b on the upper and lower sides of the end plates 20a and 20b, and a long connecting pin 64b is provided on these. The side plates 60b and 60d are attached integrally to the end plates 20a and 20b.

  The side plates 60a to 60d are formed with a plurality of screw holes 74 at both edges in the short direction, respectively, while the sides 76 of the angle members 62a to 62d are formed with holes 76 corresponding to the screw holes 74. Is done. When the screws 78 inserted into the holes 76 are screwed into the screw holes 74, the side plates 60a to 60d are fixed to each other via the angle members 62a to 62d. Thereby, the casing 24 is configured (see FIG. 4).

  In addition, while forming screw holes in the angle members 62a to 62d and forming holes in the side plates 60a to 60d and arranging the angle members 62a to 62d inward of the side plates 60a to 60d, these are integrated. Alternatively, it may be screwed.

  As shown in FIGS. 1 and 4, the side plate (one surface of the casing 24) 60 a has a desired cell voltage terminal 35 for detecting a cell voltage for each unit cell 12 or for each unit cell 12. Are provided along the stacking direction (arrow A direction) of the unit cells 12. In the openings 80a to 80n, a cell voltage detector 82 is integrally connected to a predetermined number of cell voltage terminals 35.

  The openings 80a to 80n are set to at least two different types of opening areas. In the first embodiment, the opening area gradually increases from the end plate 20a side (one end side in the stacking direction) toward the end plate 20b side (the other end side in the stacking direction), that is, the opening of the opening 80a. Area <opening area of opening 80b <... <Opening area of opening 80n-1 <opening area of opening 80n.

  As shown in FIGS. 1 and 2, the spacer member 22 has a rectangular shape set to a predetermined size so as to be positioned on the inner periphery of the casing 24. The spacer member 22 is adjusted in thickness in order to absorb a variation in the length of the stacked body 14 in the stacking direction and to apply a desired tightening load to the stacked body 14. Note that the spacer member 22 may not be used if the variation in the length of the stacked body 14 in the stacking direction can be absorbed by the elasticity of the first and second metal separators 32 and 34 themselves.

  The operation of the fuel cell stack 10 configured as described above will be described below.

  In the fuel cell stack 10, first, as shown in FIG. 4, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas supply communication hole 36a of the end plate 20a, and hydrogen is supplied to the fuel gas supply communication hole 40a. Fuel gas such as contained gas is supplied. Further, a coolant such as pure water or ethylene glycol is supplied to the coolant supply passage 38a. For this reason, in the stacked body 14, the oxidant gas, the fuel gas, and the cooling medium are supplied in the arrow A direction to the plurality of unit cells 12 stacked in the arrow A direction.

  As shown in FIG. 3, the oxidant gas is introduced into the oxidant gas flow path 52 of the second metal separator 34 through the oxidant gas supply communication hole 36 a, and along the cathode side electrode 46 of the electrolyte membrane / electrode structure 30. Move. On the other hand, the fuel gas is introduced into the fuel gas passage 48 of the first metal separator 32 through the fuel gas supply communication hole 40 a and moves along the anode side electrode 44 of the electrolyte membrane / electrode structure 30.

  Therefore, in each electrolyte membrane / electrode structure 30, the oxidant gas supplied to the cathode side electrode 46 and the fuel gas supplied to the anode side electrode 44 are consumed by an electrochemical reaction in the electrode catalyst layer, Power generation is performed.

  Next, the oxidant gas consumed by being supplied to the cathode side electrode 46 flows along the oxidant gas discharge communication hole 36b, and then is discharged to the outside from the end plate 20a. Similarly, the fuel gas consumed by being supplied to the anode side electrode 44 is discharged to the fuel gas discharge communication hole 40b, flows, and is discharged from the end plate 20a to the outside.

  The cooling medium flows in the direction of arrow B after being introduced into the cooling medium flow path 50 between the first and second metal separators 32 and 34 from the cooling medium supply communication hole 38a. The cooling medium cools the electrolyte membrane / electrode structure 30, and then moves through the cooling medium discharge communication hole 38b and is discharged from the end plate 20a.

  In this case, in the first embodiment, as shown in FIGS. 1 and 4, the side plate 60 a constituting the casing 24 has a plurality of openings corresponding to the desired cell voltage terminals 35 of the unit cells 12 to be stacked. 80a to 80n are provided along the stacking direction, and each opening area is set so as to increase sequentially from the opening 80a toward the opening 80n. For this reason, while the rigidity of casing 24 itself improves favorably, the dispersion | variation in the dimension of the lamination direction of the laminated body 14 can be absorbed reliably.

  That is, when assembling the stacked body 14 by stacking a plurality of unit cells 12 in the direction of arrow A, the unit cells 12 are sequentially stacked, for example, from the end plate 20a side. Here, due to dimensional tolerances, assembly tolerances, and the like of the parts constituting the unit cell 12, the laminate 14 is likely to have dimensional variations in the stacking direction. In particular, as the number of stacked unit cells 12 increases, dimensional variations accumulate, and relatively large variations occur on the end plate 20b side.

  Therefore, in the first embodiment, each opening area gradually increases from the opening 80a on the stacking start side to the opening 80n in which the variation in dimensions is accumulated. Therefore, it is possible to reliably absorb the variation in the dimension in the stacking direction, and it is possible to effectively prevent the attachment failure of the cell voltage detector 82, the lengthening of the wiring, and the like. Thus, the cell voltage can be easily and accurately detected for each unit cell 12 or for each of the plurality of unit cells 12.

  FIG. 5 is a partially exploded schematic perspective view of a fuel cell stack 90 according to the second embodiment of the present invention, and FIG. 6 is a perspective explanatory view of the fuel cell stack 90. The same components as those of the fuel cell stack 10 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The unit cell 92 constituting the fuel cell stack 90 includes first and second metal separators 32 and 34, and is positioned on one end side (upper end side) in the arrow C direction on the outer periphery of the first metal separator 32. Thus, the cell voltage terminal 35a is integrally formed.

  In the casing 94 constituting the fuel cell stack 90, a plurality of openings 96a to 96n corresponding to desired cell voltage terminals 35a of the plurality of unit cells 92 are provided in the side plate (other surface) 60b along the arrow A direction. It is done. In the openings 96a to 96n, cell voltage detectors 98 are integrally connected to a predetermined number of cell voltage terminals 35a.

  Similarly to the openings 80a to 80n, the openings 96a to 96n are set so that the opening area sequentially increases from the end plate 20a side to the end plate 20b side, and the openings 80a to 80n Are provided with their positions shifted in the stacking direction.

  In the second embodiment configured as described above, the cell voltage of the unit cells 92 stacked in the direction of arrow A is measured by the cell voltage detector 82 attached to the cell voltage terminal 35 from the side plate 60a side, and the side plate 60b side. To the cell voltage detector 98 attached to the cell voltage terminal 35a. For this reason, even when the unit cells 92 are arranged in close proximity to each other, the cell voltage can be easily and reliably detected for each unit cell 92 or for each of the plurality of unit cells 92. Is obtained.

  Moreover, the side plates 60a and 60b can form the openings 80a to 80n and 96a to 96n, respectively, separated by a predetermined interval. Thereby, it becomes possible to maintain the rigidity of the side plates 60a and 60b well.

  In the second embodiment, the cell voltage terminal 35a is provided at the upper end of the first metal separator 32, and the openings 96a to 96n are formed in the side plate 60b. However, the present invention is not limited to this. For example, a cell voltage terminal may be provided on the other end side in the arrow B direction of the first metal separator 32, and a plurality of openings may be formed in the side plate 60c. Alternatively, a cell voltage may be formed at the lower end of the first metal separator 32. While providing the terminal, a plurality of openings may be provided in the side plate 60d.

  Further, in the unit cell 92, two different cell voltage terminals 35 and 35a are provided. For example, three cell voltage terminals or four cell voltage terminals are provided, and any three or three of the side plates 60a to 60d are provided. You may form an opening part in all.

  FIG. 7 is an explanatory front view of the side plate 100 constituting the fuel cell stack according to the third embodiment of the present invention.

  The side plate 100 is provided with a plurality of openings 102a to 102n along the arrow A direction. Two openings 102a to 102n are provided, and each opening area is set so as to increase sequentially from the end plate 20a side to the end plate 20b side.

  In the third embodiment, two openings 102a to 102n are provided, but the number of the openings 102a to 102n may be different. A plurality of identical openings 102a are provided from the end plate 20a side to the substantially central portion of the side plate 100, while a plurality of identical openings 102n having a larger opening area than the opening 102a are provided from the central portion to the end plate 20b side. It may be provided.

  FIG. 8 is an explanatory front view of the side plate 110 constituting the fuel cell stack according to the fourth embodiment of the present invention.

  The side plate 110 is provided with an opening 102a having a minimum opening area at a substantially central portion in the direction of arrow A. Each opening area is sequentially (or a predetermined number) from the opening 102a toward the end plates 20a and 20b. Openings 112b to 112n that are larger are formed.

  In the fourth embodiment, two stacked bodies in which a predetermined number of unit cells (not shown) are stacked in advance are prepared, and the two stacked bodies overlap each other from the stacking start side unit cells. It is suitable when configuring a battery stack. That is, as compared with the central side in the stacking direction, the dimensional variation tends to increase on the end plates 20a and 20b that are both ends in the stacking direction. For this reason, by setting the opening area of the opening 112n on the side of the end plates 20a and 20b to the maximum, it is possible to reliably absorb dimensional variations.

  In addition, in the fourth embodiment, openings 102a to 102n are provided from the central portion of the side plate 110 toward both ends, and the opening area of the opening 112n is used in the first and second embodiments. It is possible to set smaller than the opening area of the openings 80n and 102n.

Figure 9 is a perspective view showing a fuel cell stack 120 that are related to the present invention.

  At least one surface of the casing 24 constituting the fuel cell stack 120 includes first and second side plates 122 and 124 that are juxtaposed in a direction (arrow C direction) that intersects the stacking direction of the unit cells 12. Between the first and second side plates 122 and 124, a gap 126 corresponding to the cell voltage terminal 35 for detecting the cell voltage for each unit cell 12 or for each of the plurality of unit cells 12 is provided in the stacking direction of the unit cells 12. It is provided along.

In the fuel cell stack 120 configured as described above, it is only necessary to provide a predetermined gap 126 between the first and second side plates 122 and 124. As a result, the degree of freedom of shape of the first and second side plates 122 and 124 is improved, the rigidity of the first and second side plates 122 and 124 is easily increased, and the shape is simplified and economical. Is obtained.

1 is a partially exploded schematic perspective view of a fuel cell stack according to a first embodiment of the present invention. 2 is a cross-sectional side view of the fuel cell stack. FIG. It is a disassembled perspective explanatory drawing of the unit cell which comprises the said fuel cell stack. It is a perspective view of the fuel cell stack. FIG. 4 is a partially exploded schematic perspective view of a fuel cell stack according to a second embodiment of the present invention. It is a perspective view of the fuel cell stack. It is front explanatory drawing of the side plate which comprises the fuel cell stack which concerns on the 3rd Embodiment of this invention. It is front explanatory drawing of the side plate which comprises the fuel cell stack which concerns on the 4th Embodiment of this invention. It is a perspective view showing a fuel cell stack that are related to the present invention. It is a perspective explanatory view at the time of forming an opening part long in the laminating direction on the side plate. It is a perspective explanatory view at the time when a plurality of openings are formed in a staggered pattern in the stacking direction on the side plate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 90, 120 ... Fuel cell stack 12 ... Unit cell 14 ... Laminated body 16a, 16b ... Terminal plate 18 ... Insulating plate 20a, 20b ... End plate 22 ... Spacer member 24, 94 ... Casing 30 ... Electrolyte membrane electrode structure 32, 34 ... Metal separators 35, 35a ... Cell voltage terminal 42 ... Solid polymer electrolyte membrane 44 ... Anode side electrode 46 ... Cathode side electrode 48 ... Fuel gas flow path 50 ... Cooling medium flow path 52 ... Oxidant gas flow path 60a -60d, 100, 110, 122, 124 ... side plates 62a-62d ... angle members 64a, 64b ... connecting pins 80a-80n, 96a-96n, 102a-102n, 112a-112n ... openings 82, 98 ... cell voltage detectors 126 ... Gap

Claims (3)

A fuel cell stack comprising a unit cell in which a pair of electrodes provided on both sides of an electrolyte is sandwiched between separators, and a stacked body in which a plurality of the unit cells are stacked is housed in a box-shaped casing. And
In at least one surface of the casing, a plurality of openings corresponding to desired cell voltage terminals are provided in the stacking direction of the unit cells in order to detect a cell voltage for each unit cell or for each unit cell. Along the line,
The fuel cell stack, wherein the plurality of openings are set so that an opening area increases from one end side to the other end side in the stacking direction . A pair of electrodes provided on both sides of the electrolyte electrolyte electrode assembly, comprising a unit cell is sandwiched by a separator, Oh in the fuel cell stack to accommodate a stack of the unit cells are stacked in a box-shaped casing in Tsu,
In at least one surface of the casing, a plurality of openings corresponding to desired cell voltage terminals are provided in the stacking direction of the unit cells in order to detect a cell voltage for each unit cell or for each unit cell. Along the line,
The fuel cell stack, wherein the plurality of openings are set so that an opening area increases from a center side in a stacking direction toward both end sides. 3. The fuel cell stack according to claim 1, wherein a plurality of openings corresponding to the cell voltage terminals are provided on the other surface of the casing, the positions being shifted from the plurality of openings in the stacking direction. A fuel cell stack characterized by

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