JP2014127393A - Fuel cell stack and seal plate for use therein - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress deformation of a separator caused by power generation gas, while reducing and adjusting pressure loss in a cooling circulation path.SOLUTION: A fuel cell stack includes a plurality of fuel cells in which a pair of separators are disposed on both sides of a cell frame where a membrane electrode assembly is arranged, so as to section and form gas circulation paths for circulating two kinds of different power generation gas, respectively, more than one cell module M laminating these fuel cells each other, and a seal plate P1 interposed between these cell modules M, M and bonded. Separator displacement suppression means 50 for suppressing displacement of separators 25, 25 is interposed therebetween.

Description

  The present invention relates to a fuel cell stack and a seal plate used therefor.

  As a technique related to this type of fuel cell stack, the present applicant has filed an application as Patent Document 1 under the name of “seal plate and fuel cell stack using the same”. Patent Document 1 was filed on March 9, 2012, and the application has not been published at the time of filing this application.

The fuel cell stack described in Patent Document 1 is used by interposing and adhering between at least two cell modules in which a plurality of fuel cells are stacked and integrated with each other. A plurality of manifold holes for separating and flowing in and out of the two kinds of power generation gas flowing are formed, and the power generation gas flowing through each manifold hole is sealed at the peripheral edge of each manifold hole. The sealing member for this is coupled.
According to this configuration, by adopting the seal plate provided with the seal member, the cell module can be easily removed, so that the cell module can be continuously used and the pressure loss in the cooling flow passage can be reduced and adjusted. The effect that can be obtained.

Japanese Patent Application No. 2012-053310

  However, in the fuel cell stack described in Patent Document 1, the power generation gas (hydrogen-containing gas) is pulsated to discharge water generated in the fuel cell stack, but the separator also accompanies the pulsation. The deformation repeatedly occurs, and the deformation may cause the membrane electrode assembly to be damaged due to stress.

  Accordingly, an object of the present invention is to provide a fuel cell stack that can suppress the displacement of the separator caused by the power generation gas and can reduce and adjust the pressure loss in the cooling flow passage, and a seal plate used therefor.

  In order to solve the above problems, the present invention provides a pair of gas flow passages for distributing two different types of power generation gas on both sides of a cell frame provided with a membrane electrode assembly. A fuel cell stack having a plurality of fuel cells provided with separators, two or more cell modules in which the fuel cells are stacked on each other, and a seal plate used by being inserted and bonded between the cell modules. In addition, separator displacement suppression means for suppressing the displacement of the separator is interposed between the separators with the seal plate interposed therebetween.

  In said structure, the displacement of a separator is suppressed by the separator displacement suppression means interposed between the said seal plate and both separators.

  According to the present invention, since the separator displacement suppression means is interposed between the seal plate and both separators, the displacement of the separator caused by the power generation gas can be suppressed and the pressure loss in the cooling flow passage can be reduced. Can be adjusted.

1 is a perspective view of a fuel cell stack according to an embodiment of the present invention. It is a disassembled perspective view of a fuel cell stack same as the above. It is an enlarged front view of the cell frame which makes a part of fuel cell. It is an enlarged front view of the separator which makes a part of fuel cell same as the above. It is an enlarged front view of a seal plate same as the above. It is an enlarged front view which arrange | positioned the separator displacement suppression means which concerns on an example in opening of the seal plate same as the above. It is an enlarged view of the part which follows the II line | wire shown in FIG. It is a figure which shows the relationship between the displacement of a membrane electrode assembly, and a separator displacement suppression means. It is a figure which shows the relationship between the stress which arises in a membrane electrode assembly, and the presence or absence of a separator displacement suppression means. It is a figure which shows the relationship between the repeated bending stress added to a membrane electrode assembly, and the number of repetitions. It is a figure which shows the relationship between the stress which arises in a membrane electrode assembly, and a displacement amount. (A)-(E) are the elements on larger scale which show the seal plate which formed the pressure loss adjustment part which concerns on a 2nd example-a 6th example. In addition, about the thing equivalent to what was demonstrated in embodiment mentioned above, the code | symbol same as them is attached | subjected and description is abbreviate | omitted. It is a front view of the seal plate which shows the form which has arrange | positioned the separator displacement suppression means to the side edge part of an active area. It is a front view which shows the relationship between a separator displacement suppression means same as the above and a cell frame. It is a partial expanded sectional view which follows the II-II line | wire shown in FIG.

  EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated with reference to drawings. 1 is a perspective view of a fuel cell stack according to an embodiment of the present invention, FIG. 2 is an exploded perspective view of the fuel cell stack, and FIG. 3 is an enlarged front view of a cell frame forming a part of the fuel cell. It is. 4 is an enlarged front view of a separator that forms part of the fuel cell, FIG. 5 is an enlarged front view of the seal plate, and FIG. 6 is an example of a separator displacement suppression according to an opening of the seal plate. It is an enlarged front view which arrange | positioned the means.

  As shown in FIGS. 1 and 2, a fuel cell stack A according to an embodiment of the present invention includes fuel cell modules M and M and a seal plate P1 stacked between a pair of end plates 10 and 11, and The fuel cell modules M and M and the seal plate P1 are clamped by the end plates 10 and 11, and are fastened by the fastening plates 12 and 13 and the reinforcing plates 14 and 15.

  The cell module M is formed by laminating fuel cells 20 having a required number, and the outer wall surface of the cell module M is molded with an adhesive layer. As a result, water intrusion into the cell module M is prevented and electrical insulation is achieved.

The fuel cell 20 described above has a pair of separators 25 so as to partition and form gas flow passages F2 and F3 (see FIG. 15) for flowing two different types of power generation gas on both sides of the cell frame 21, respectively. , 25 are arranged.
“Two types of power generation gas” are a hydrogen-containing gas and an oxygen-containing gas.

The cell frame 21 is made of resin. In the present embodiment, as shown in FIG. 3, the cell frame 21 has a horizontal rectangle in a front view as viewed from the stacking direction α of the fuel cells 20 and a constant plate thickness. Formed.
A membrane electrode assembly 22 is disposed at the center of the cell frame 21, and manifold portions ML and MR are disposed on both sides (both ends) of the membrane electrode assembly 22.
An outer peripheral seal member 23 is formed along the outermost peripheral edge of the cell frame 21, and an inner peripheral seal member 24 is formed in an endless shape over the entire circumference inside the seal member 23 at a predetermined interval. .

  The membrane electrode assembly 22 is also called MEA (Membrane Electrode Assembly), and has a structure in which an electrolyte membrane made of, for example, a solid polymer is sandwiched between a pair of electrodes.

  The manifold parts ML and MR are used for flowing in and out of hydrogen-containing gas, oxygen-containing gas and cooling fluid, respectively. Between the manifold parts ML and MR and the membrane electrode assembly 22, hydrogen is contained. Diffuser regions D1 and D1, which are gas or oxygen-containing gas flow regions, are formed. The cooling fluid shown in this embodiment is “water”.

  The manifold portion ML on one side includes a hydrogen-containing gas supply hole M1, a cooling fluid supply hole M2, and an oxygen-containing gas supply hole M3, and forms respective flow paths in the stacking direction α.

  The other manifold portion MR includes an oxygen-containing gas discharge hole M4, a cooling fluid discharge hole M5, and a hydrogen-containing gas discharge hole M6, and forms respective flow paths in the stacking direction α. It should be noted that a part or all of the supply and discharge may be in a reverse positional relationship.

The diffuser region D1 is formed on both surfaces of the cell frame 21 between the membrane electrode assembly 22 and the manifold portion ML and between the membrane electrode assembly 22 and the manifold portion MR.
In the diffuser region D1, a plurality of rectifying projections 9 having the same shape and the same size in the shape of a truncated cone are arranged in two rows at a predetermined interval.

In the cell frame 21, an adhesive seal 7 is continuously formed in an endless manner along the outer edge, and the adhesive seal 7 is formed so as to surround the manifold holes M2 and M5.
Each of the separators 25 and 25 is formed by press-molding a metal plate such as stainless steel, and is formed in a horizontal rectangle having substantially the same size as the cell frame 21 described above.

  The separator 25 has a flow passage forming portion 25a continuous in the longitudinal direction at the central portion facing the membrane electrode assembly 22, and both manifolds of the cell frame 21 are formed at both ends. Facing the holes M1 to M6, manifold holes M1 to M6 having the same shape and the same size as these are formed to face each other.

Diffuser regions D2 and D2 are formed between the manifold part ML and the gas inflow end of the flow path forming part 25a, and between the manifold part MR and the gas outflow end of the flow path forming part 25a.
In the diffuser region D2, a plurality of protrusions 8 having the same shape and the same size in the shape of a truncated cone are arranged in a lattice pattern at a required interval.

FIG. 7 is an enlarged view of a portion along line II shown in FIG.
A space defined by the fuel cells 20 and 20 arranged on the opposing surfaces of the two adjacent cell modules M and M, that is, the outermost fuel cells 20 and 20 is a cooling fluid flow passage (hereinafter referred to as “cooling fluid flow passage”). F1 and the cooling fluid flow passage F1 is inserted with the seal plate P1 according to the first embodiment of the present invention.
Specifically, a cooling fluid flow passage F1 is defined between the separators 25 and 25 of the fuel cells 20 and 20 facing each other.

  The seal plate P1 according to the first embodiment of the present invention is formed separately from the fuel cell 20 described above, and is formed by opening manifold portions ML and MR at both ends of the plate substrate 30. And the pressure loss adjusting part B1 according to the first example is formed.

The plate substrate 30 is formed by molding a single conductive metal plate, and is formed to have substantially the same shape and size as the fuel cell 20 described above in plan view. By forming the plate substrate 30 with a conductive metal plate, it is possible to maintain stable current conduction over time.
The manifold portions ML and MR formed on the plate substrate 30 are the same as those formed on the cell frame 21 and the like, and thus the description thereof is omitted.

  When the seal plate P1 is inserted in the cooling fluid flow path F1 between the cell modules M and M, the manifold holes M1 to M3 and M4 to M6 formed in the seal plate P1 are the cell modules described above. A series of flow passages are formed with the manifold holes M1 to M3 and M4 to M6 formed in M and M.

In the present embodiment, the seal members 31 to 34 are provided at the respective edge portions of the plate substrate 30 that partition and form the manifold holes M1, M3, M4, and M6 of the seal plate P1. An outer peripheral seal member 35 is formed along the outer peripheral edge, and an inner peripheral seal member 36 is formed endlessly on the entire periphery of the seal member 35 at a predetermined interval.
The inner peripheral sealing member 36 prevents leakage of the cooling fluid flowing through the cooling fluid flow passage F1, and the outer peripheral sealing member 35 prevents rain water from entering from the outside, and is electrically insulated. .

  The pressure loss adjusting unit B1 according to the first example described above has a function of increasing or decreasing the pressure loss of the cooling fluid flowing through the cooling fluid flow passage F1 shown in FIG. The pressure loss can be increased or decreased by increasing or decreasing the cross section of the cooling fluid level flow passage F1.

“Increase / decrease in cross section of the cooling fluid flow passage F1” includes both the flow direction β of the cooling fluid and the direction γ orthogonal to the flow direction β.
The “active area a” is a region facing the membrane electrode assembly 22 described above.

The pressure loss adjusting unit B1 shown in the present embodiment is provided in the vicinity of the active area.
The pressure loss adjusting unit B1 includes two openings (hereinafter referred to as “slits”) 37 and 37 parallel to the short axis center line O2 orthogonal to the long axis center line O1 of the plate substrate 30.
The slit 37 is formed in a rectangular shape having a length substantially equal to the width of the cooling fluid flow path in plan view.
The “major axis center line O1” is set to a position that bisects the short side of the plate substrate 30, and the minor axis center line O2 is set to a position that bisects the diffuser regions D2 and D2.

In this embodiment, the separator displacement suppression means 50 which suppresses the displacement of each separator 25 is arrange | positioned so that the distribution property of a cooling fluid may improve.
“To improve flow distribution” means that the cooling fluid has a required flow velocity form in the direction of the short axis center line O2.

  In the present embodiment, the separator displacement suppressing means 50 is disposed in the slits 37 and 37 at equal intervals along the short axis center line O2. You may arrange | position to the space | interval which becomes sparse toward a side from a part, and may be arranged at the space | interval which becomes dense toward a side from a center part. Moreover, it can also arrange in a grid | lattice form etc.

The separator displacement suppression means 50 is made of, for example, resin, and is formed in a cylindrical shape having a height extending between two separators 25 and 25 adjacent to the seal plate P1, and both ends are bonded to the separators 25 and 25. It is fixed.
Thereby, the displacement margin of each separator 25 is narrowed, and the displacement of the separator 25 is suppressed by transmitting the load in the stacking direction α by the separator displacement suppression means 50.

Thereby, the deformation | transformation of the separator 25 accompanying the pulsation of hydrogen-containing gas can be suppressed, the bending stress added to the membrane electrode assembly 22 can be reduced, and the lifetime can be extended.
In addition, it is possible to prevent the occurrence of cracks or the like at the joint portions between the two side edges 22a and 22b facing the diffuser regions D2 and D2 of the membrane electrode assembly 22 and the cell frame 21.

  Although there is a suspicion that the protrusions 8 disposed in the diffuser region D2 described above may function as the separator displacement suppression means 50, the protrusions 8 are at a height extending between the separators 25 and 25. Therefore, in this embodiment, the function of the separator displacement suppression means 50 is not achieved.

  FIG. 8 is a diagram showing the relationship between the displacement of the membrane electrode assembly and the separator displacement suppression means, FIG. 9 is a diagram showing the relationship between the stress generated in the membrane electrode assembly and the presence or absence of the separator displacement suppression means, and FIG. FIG. 11 is a diagram showing the relationship between the repeated bending stress applied to the membrane electrode assembly and the number of repetitions, and FIG. 11 is a diagram showing the relationship between the stress generated in the membrane electrode assembly and the amount of displacement. 8 to 11, the membrane electrode assembly is expressed as “MEA-ASSY”, and the presence / absence of the separator displacement suppression means is indicated as “Yes” or “No”.

  As is apparent from FIG. 8, the displacement of the membrane electrode assembly 22 is suppressed by setting the separator displacement suppression means 50 to a height extending between the separators 25 and 25. Further, as is clear from FIG. 9, when the separator displacement suppression means 50 is provided, the stress generated in the membrane electrode assembly 22 is reduced.

  As is apparent from FIG. 10, when the separator displacement suppressing means 50 is provided, the number of repetitions, that is, the life is significantly extended. Further, as shown in FIG. 11, it is clear that the stress generated in the membrane electrode assembly 22 becomes constant as the displacement amount of the separators 25, 25 becomes constant.

  FIGS. 12A to 12E are partially enlarged views showing seal plates on which pressure loss adjusting portions according to second to sixth examples are formed. In addition, about the thing equivalent to what was demonstrated in embodiment mentioned above, the code | symbol same as them is attached | subjected and description is abbreviate | omitted.

A seal plate P2 shown in FIG. 12A is formed with a pressure loss adjusting portion B2 according to the second example.
The pressure loss adjusting portion B2 according to the second example is obtained by dividing the slit 37 into ribs 37a and 37a so as to be divided into three equal parts in the direction of the minor axis center line O2.
In this case, the protrusions 8 disposed in the diffuser region D2 come into contact with both surfaces of the ribs 38 and 38, and thereby the protrusions 8 exhibit functions equivalent to those of the separator displacement suppression means 50 described above. Further, by arranging the ribs 37a, 37a in the slit 37, the rigidity of the portion can be increased.

A seal plate P3 shown in FIG. 12B is formed with a pressure loss adjusting portion B3 according to the third example.
The pressure loss adjusting portion B3 according to the third example has a plurality of adjusting holes 38 which are parallel to the short axis center line O2 and have the same diameter and are arranged in two rows at a constant interval. It is a thing. Also in this example, the protrusions 8 disposed in the diffuser region D2 are in contact with both surfaces in the vicinity of the adjustment hole 38, whereby the protrusions 8 perform the same function as the separator displacement suppression means 50 described above. .

The seal plate P4 shown in FIG. 12C is formed with the pressure loss adjusting portion B4 according to the fourth example.
The pressure loss adjusting portion B4 according to the fourth example has a plurality of adjusting holes 38 that are parallel to the short axis center line O2 and have the same diameter, and are arranged in three rows at regular intervals. It is a thing. Also in this example, the protrusions 8 disposed in the diffuser region D2 are in contact with both surfaces in the vicinity of the adjustment hole 38, whereby the protrusions 8 perform the same function as the separator displacement suppression means 50 described above. .

A seal plate P5 shown in FIG. 12D is obtained by forming the pressure loss adjusting portion B5 according to the third example.
The pressure loss adjusting unit B5 according to the third example is configured by arranging a plurality of adjusting holes 39 in the same rectangular shape on the short axis center line O2 in a line at a constant interval. In this example, the protrusions 8 disposed in the diffuser region D2 are in contact with both surfaces in the vicinity of the adjustment hole 39, so that the protrusions 8 perform the same function as the separator displacement suppression means 50 described above. .

A seal plate P6 shown in FIG. 12 (E) is obtained by forming the pressure loss adjusting portion B6 according to the third example.
The pressure loss adjusting unit B6 according to the third example is configured by arranging a plurality of adjusting holes 40 parallel to the short axis center line O2 and having the same square shape in two rows at a constant interval. is there. In this example, the protrusions 8 disposed in the diffuser region D2 are in contact with both surfaces in the vicinity of the adjustment hole 40, so that the protrusions 8 perform the same function as the separator displacement suppression means 50 described above. .

  FIG. 13 is a front view of a seal plate showing a configuration in which separator displacement suppression means is arranged on the side edge of the active area, and FIG. 14 is a front view showing the relationship between the separator displacement suppression means and the cell frame. 15 is a partially enlarged sectional view taken along the line II shown in FIG. In addition, about the thing equivalent to what was demonstrated in embodiment mentioned above, the code | symbol same as them is attached | subjected and description is abbreviate | omitted.

The seal plate P7 shown in FIGS. 13 to 15 is provided with the seals 51a and 51a extending over the lengths of the slits 37 and 37, in other words, the side edges of the active area. .
In the present embodiment, the seals 51a and 51a are separator displacement suppression means B7.

  When spread, the above-described seals 51 a and 51 a are disposed at the joint portions b and b between the membrane electrode assembly 22 and the cell frame 21 as shown in FIGS. By arranging the seals 51a and 51a at the joint portions b and b, the bending stress applied to the membrane electrode assembly 22 due to the pulsation of the hydrogen-containing gas can be reduced, and the long side of the membrane electrode assembly 22 can be reduced. Generation | occurrence | production of the crack etc. in the said junction part b of the edge and the cell frame 21 can be prevented.

The present invention is not limited to the above-described embodiments, and the following modifications can be made.
-In above-mentioned embodiment, although the thing of the structure which has arrange | positioned the separator displacement suppression means between both the separators which inserted the seal plate was demonstrated as an example, it can also arrange | position between an end plate and a separator.

As described above in detail, in any case, each configuration described in each of the above embodiments is not limited to being applied only to each of the above embodiments, but the configuration described in one embodiment is replaced by another embodiment. It can be applied mutatis mutandis or applied to it, and it can be arbitrarily combined.

8 Projection 20 Fuel cell 22 Membrane electrode assembly 21 Cell frame 25 Separator 37 Pressure loss adjusting opening 50 Separator displacement suppression means D Diffuser region F1 Cooling fluid flow path F2, F3 Gas flow path M Cell module ML, MR Manifold part P1 ~ P7 Seal plate b Joint part

Claims (9)

A plurality of fuel cells each having a pair of separators disposed on both sides of a cell frame on which a membrane electrode assembly is disposed so as to form gas flow passages for distributing two different types of power generation gas, respectively; ,
Two or more cell modules in which those fuel cells are stacked, and
A fuel cell stack having a seal plate used by interposing and bonding between the cell modules,
A fuel cell stack, characterized in that separator displacement suppression means for suppressing displacement of the separators is interposed between both separators having the seal plate interposed therebetween. A cooling fluid flow passage for allowing the cooling fluid to flow through the opposing surfaces of two adjacent cell modules is defined, and the pressure loss adjustment for adjusting the pressure loss of the cooling fluid in the cooling fluid flow passage is increased or decreased. A seal plate with an opening for insertion is inserted,
2. The fuel cell stack according to claim 1, wherein separator displacement suppressing means is disposed in the pressure loss adjusting opening. The cell frame is formed with a manifold part for respectively flowing in and out of two kinds of power generation gas, and a hydrogen-containing gas or oxygen-containing gas flow region between the manifold part and the membrane electrode assembly. A diffuser region is disposed,
3. The fuel cell stack according to claim 1, wherein a pressure loss adjusting opening is formed in the diffuser region so as to face the diffuser region.   The fuel cell stack according to any one of claims 1 to 3, wherein a separator displacement suppressing means is interposed between both separators sandwiching the seal plate.   The fuel cell stack according to claim 4, wherein the separator displacement suppression means is formed at a height that makes contact with both separators.   The fuel cell stack according to any one of claims 3 to 5, wherein the separator displacement suppression means is a protrusion disposed in the diffuser region.   The fuel cell stack according to any one of claims 1 to 6, wherein separator displacement suppressing means is disposed between the end plate and the separator.   The fuel cell stack according to any one of claims 1 to 7, wherein the separator displacement suppression means is disposed along a joint portion between the membrane electrode assembly and the cell frame.   The fuel cell stack according to any one of claims 1 to 8, wherein the separator displacement suppression means is arranged so as to improve the flowability of the cooling fluid.

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