JP6569503B2 - Fuel cell seal structure - Google Patents

Description

  The present invention relates to a seal structure for a fuel cell.

  Generally, a fuel cell has a stack structure in which a plurality of single cells are stacked. Each single cell has a membrane electrode assembly and two separators sandwiching the membrane electrode assembly. The separator is formed with a reaction gas channel for flowing a reaction gas in the single cell and a cooling medium channel for flowing a cooling medium in the single cell. The separator is formed with a reaction gas manifold that functions as an inlet and an outlet for the reaction gas, and a cooling medium manifold that functions as an inlet and an outlet for the cooling medium flow path. Around the reaction gas flow path, the cooling medium flow path, the reaction gas manifold, and the cooling medium manifold, seal members for suppressing leakage of the respective fluids are provided as appropriate. Further, Patent Document 1 discloses an example in which inclined walls are formed on the outer peripheral side and the inner peripheral side of the sealing members on the surface of the separator, respectively.

JP 2014-216247 A

  However, in the prior art, when an internal pressure is applied to the seal member, the seal member hits the inclined wall on the outer peripheral side and rides on the inclined wall, and there is a problem that sufficient sealing performance may not be ensured.

  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 forms.

(1) According to one aspect of the present invention, a fuel cell seal structure is provided. This fuel cell seal structure has a seal member that is disposed on the surface of a separator of a single cell of the fuel cell and is disposed between adjacent single cells. The separator includes an outer peripheral inclined wall formed on the outer peripheral side of the seal member so as to be inclined toward the outer peripheral direction of the separator. The seal member includes a center seal portion that seals between the single cells, and a peripheral seal portion that is formed integrally with the center seal portion on both sides of the center seal portion and has a smaller thickness than the center seal portion. Prepare. A width of the peripheral seal portion provided on the outer peripheral side of the central seal portion is configured to be larger than a width of the outer peripheral inclined wall in a plan view of the separator.

  According to this form of the seal structure, when internal pressure is applied to the seal member, the seal member moves in the direction of the outer peripheral inclined wall, and the peripheral peripheral seal portion contacts the outer peripheral inclined wall before the central seal portion. . Since the width of the peripheral seal portion on the outer peripheral side is larger than the width of the outer peripheral inclined wall, the movement of the seal member stops before the central seal portion hits the outer peripheral inclined wall. Thus, by making the width of the outer peripheral side peripheral seal portion larger than the width of the outer peripheral inclined wall, the central seal portion that functions to seal between the single cells does not run on the outer peripheral inclined wall. Sealability can be secured.

  The present invention can be realized in various forms other than the above-described seal structure. For example, it can be realized in the form of a separator for a fuel cell having the above-described seal structure, a single cell of a fuel cell having the separator, a fuel cell having the single cell, a fuel cell system having the fuel cell, and the like.

It is explanatory drawing which shows schematic structure of the fuel cell system in 1st Embodiment of this invention. It is the schematic plan view which looked at the anode side separator of the single cell from the opposite side to MEA. It is a schematic plan view which expands and shows the oxidizing agent gas outlet manifold vicinity in 1st Embodiment. It is explanatory drawing which shows the cross section of the sealing member in 1st Embodiment. It is explanatory drawing which shows the cross section of the sealing member in 2nd Embodiment. It is explanatory drawing which shows the cross section of the sealing member in 3rd Embodiment. It is a schematic plan view which expands and shows the oxidizing agent gas outlet manifold vicinity in 4th Embodiment. It is explanatory drawing which shows the cross section of the sealing member in 4th Embodiment.

A. First embodiment:
FIG. 1 is an explanatory diagram showing a schematic configuration of a fuel cell system 10 according to the first embodiment of the present invention. The fuel cell system 10 includes a fuel cell stack 100. In the fuel cell stack 100, an end plate 110, an insulating plate 120, a current collecting plate 130, a plurality of single cells 140, a current collecting plate 130, an insulating plate 120, and an end plate 110 are laminated in this order. Has a stacked structure. Note that the stacking direction of the single cells 140 is a direction X perpendicular to the vertical direction Y.

  Hydrogen as fuel gas is supplied to the fuel cell stack 100 from a hydrogen tank 150 that stores high-pressure hydrogen via a shut valve 151, a regulator 152, and a pipe 153. The fuel gas (anode off gas) not used in the fuel cell stack 100 is discharged to the outside of the fuel cell stack 100 via the discharge pipe 163. The fuel cell system 10 may have a recirculation mechanism that recirculates the anode off gas to the pipe 153 side. The fuel cell stack 100 is also supplied with air as an oxidant gas via the air pump 160 and the pipe 161. The oxidant gas (cathode off gas) that has not been used in the fuel cell stack 100 is discharged to the outside of the fuel cell stack 100 via the discharge pipe 154. The fuel gas and the oxidant gas are also called reaction gas.

  Further, the cooling medium cooled by the radiator 170 is supplied to the fuel cell stack 100 via the water pump 171 and the pipe 172 in order to cool the fuel cell stack 100. The cooling medium discharged from the fuel cell stack 100 is circulated to the radiator 170 via the pipe 173. As the cooling medium, for example, water, antifreeze water such as ethylene glycol, air, or the like is used. In this example, water (also referred to as “cooling water”) is used as the cooling medium.

  The unit cell 140 provided in the fuel cell stack 100 includes a membrane electrode assembly (also referred to as MEA) 30 in which an anode and a cathode are arranged on both surfaces of an electrolyte membrane, respectively, as a pair of separators, that is, an anode side separator 50 and a cathode side. The structure is sandwiched between the separators 40. The anode-side separator 50 includes a plurality of streaky fuel gas flow channel grooves 52 on the surface on the MEA 30 side, and includes a plurality of streaky cooling medium flow channel grooves 54 on the surface opposite to the MEA 30. The cathode side separator 40 includes a plurality of oxidant gas flow channel grooves 42 in a streak shape on the surface on the MEA 30 side. An insulating resin frame member 32 is provided on the outer periphery of the MEA 30 sandwiched between the anode side separator 50 and the cathode side separator 40.

  FIG. 2 is a schematic plan view of the anode separator 50 of the single cell 140 as viewed from the side opposite to the MEA 30. In FIG. 2, the front and back direction is the stacking direction X, and the up and down direction is the vertical direction Y. Further, the horizontal direction in the figure perpendicular to the vertical direction Y and the stacking direction X is the horizontal direction Z. The anode-side separator 50 and the cathode-side separator 40 are composed of members having gas barrier properties and electron conductivity. For example, a carbon-made member such as dense carbon that is made gas impermeable by compressing carbon particles, It is made of a press-molded metal member such as stainless steel or titanium steel. In the present embodiment, the separators 40 and 50 are metal press separators.

  A fuel gas inlet manifold 62, a coolant outlet manifold 84, and an oxidant gas inlet manifold 72 are arranged in order from the top in the vertical direction Y at one edge of the anode separator 50 in the horizontal direction Z. Has been. In contrast, an oxidant gas outlet manifold 74, a cooling medium inlet communication manifold 82, and a fuel gas outlet manifold 64 are arranged along the vertical direction Y in order from the top at the other end edge. Yes. The fuel gas inlet communication manifold 62 and the fuel gas outlet manifold 64, the oxidant gas inlet communication manifold 72 and the oxidant gas outlet manifold 74, the cooling medium inlet communication manifold 82 and the cooling medium outlet manifold 84 are arranged on both sides in the horizontal direction Z. It arrange | positions so that it may mutually oppose in an outer edge part.

  The fuel gas supplied from the fuel gas inlet manifold (not shown) of the cathode separator 40 is distributed to the fuel gas passage groove 52 (FIG. 1) of the single cell 140, and then the fuel gas flow is made by the fuel gas outlet manifold 64. The fuel gas that is not used in the road groove 52 is collected and discharged to the outside of the fuel cell stack 100. Further, the oxidant gas supplied from the oxidant gas inlet manifold (not shown) of the cathode separator 40 is distributed to the oxidant gas flow channel 42 (FIG. 1) of the single cell 140, and then the oxidant gas outlet. The oxidant gas that has not been used in the oxidant gas flow path groove 42 is collected by the manifold 74 and discharged to the outside of the fuel cell stack 100. Further, the cooling medium supplied from the cooling medium inlet manifold (not shown) of the cathode side separator 40 is diffused through one end provided with the dimple 56 of the anode side separator 50 and flows through the cooling medium flow channel groove 54. The coolant is collected by the coolant outlet manifold 84 from the coolant passage groove 54 through the other end where the dimples 56 are provided, and discharged to the outside of the fuel cell stack 100. Further, the cooling medium inlet communication manifold 82, the cooling medium flow channel groove 54, and the cooling medium outlet manifold 84 communicate with each other in the horizontal direction Z on a plane viewed from the opposite side of the anode separator 50 from the MEA 30. The cooling medium flow path surface 200 is configured. Each manifold 62, 64, 72, 74, 82, 84 has a substantially rectangular opening. Each manifold has a shape extending in the stacking direction X of the fuel cell stack 100.

  Seal members SL1 to SL5 (also referred to as “gaskets”) surrounding the respective reaction gas manifolds 62, 64, 72, and 74 and the cooling medium flow path surface 200 are provided on a plane viewed from the opposite side of the anode separator 50 from the MEA 30. A sealing structure is formed. The sealing members SL <b> 1 to SL <b> 5 have a function of abutting against the surface of another adjacent single cell 140 when the plurality of single cells 140 are stacked and sealing between the two single cells 140. Specifically, the seal members SL1 and SL2 are for suppressing the leakage of fuel gas, the seal members SL3 and SL4 are for suppressing the leakage of the oxidant gas, and the seal member SL5 is the cooling medium. This is to suppress the leakage of water. These seal members SL1 to SL5 are formed by injection molding, press molding, or the like, and rubber, thermoplastic elastomer, or the like can be used as the material of the seal members SL1 to SL5. Further, the seal members SL1 to SL5 are fixed by being bonded to the separator with an adhesive. An outer peripheral side inclined wall 81 and an inner peripheral side inclined wall 83 are formed on both sides of these seal members SL1 to SL5.

  FIG. 3 is an enlarged schematic plan view showing the vicinity of the oxidant gas outlet manifold 74 of the anode-side separator 50 shown in FIG. The seal member SL4 has a center seal portion 21 and a peripheral seal portion 22. Next to the seal member SL4, a cooling medium seal member SL5 is formed.

  FIG. 4 is an explanatory view showing an AA section of the seal member SL4 shown in FIG. The central seal portion 21 of the seal member SL4 functions when sealing between the two single cells 140 in a state where the plurality of single cells 140 are stacked. The peripheral seal portion 22 of the seal member SL4 is formed integrally with the central seal portion 21 on both sides of the central seal portion 21 and is configured to be thinner than the central seal portion 21. In this specification, “thickness” means a dimension in the stacking direction of the single cells 140. Further, the width Wb of the peripheral seal portion 22 is configured to be larger than the width Ww of the outer peripheral inclined wall 81. In addition, the shape characteristic in seal member SL4 is the same also in other seal members SL1-SL3, SL5.

  FIG. 4A is an explanatory diagram showing a state in which no pressure is applied to the seal member SL4. The cathode-side separator 40 indicated by a broken line is that of another adjacent unit cell 140. FIG. 4B is an explanatory diagram showing a state in which the cathode separator 40 of another adjacent single cell 140 is in contact with the anode separator 50 when the fuel cell stack 100 is assembled. At this time, the central seal portion 21 of the seal member SL4 hits the cathode separator 40 and is compressed and deformed in the stacking direction of the single cells 140. FIG. 4C is an explanatory diagram showing a state in which an internal pressure (white arrow) is applied to the seal member SL4. When internal pressure is applied to the seal member SL4, the seal member SL4 moves in the direction of the outer peripheral inclined wall 81, and the outer peripheral peripheral edge seal portion 22 contacts the outer peripheral inclined wall 81 before the central seal portion 21. Since the width Wb of the outer peripheral side peripheral seal portion 22 is larger than the width Ww of the outer peripheral inclined wall 81, the movement of the seal member SL4 stops before the central seal portion 21 hits the outer peripheral inclined wall 81. Thus, by making the width Wb of the peripheral edge seal portion 22 on the outer peripheral side larger than the width Ww of the outer peripheral inclined wall 81, the central seal portion 21 that functions to seal between the single cells 140 becomes the outer peripheral inclined wall 81. A sufficient sealing performance can be ensured without riding on. Of the two peripheral seal portions 22 on both sides of the central seal portion 21, the width of the inner peripheral peripheral seal portion 22 may be smaller than the width Ww of the outer peripheral inclined wall 81. Further, in the peripheral edge seal portion 22 on the outer peripheral side, the portion that moves and hits the outer peripheral inclined wall 81 is a portion that runs in parallel with the outer peripheral inclined wall 81, and the other portion (the seal member for the cooling medium in FIG. 3). There is no possibility that the portion running in parallel with SL5 will hit the outer peripheral inclined wall 81. Accordingly, the width Wb of the outer peripheral side peripheral seal portion 22 may be made larger than the width Ww of the outer peripheral side inclined wall 81 only in a portion that may hit the outer peripheral side inclined wall 81.

B. Second embodiment:
FIG. 5 is an explanatory view showing a cross section of the seal member SL4a in the second embodiment. The only difference from the first embodiment shown in FIG. 4 is that the thickness of a part of the peripheral seal portion 22a is increased. Is omitted.

  Of the peripheral seal portion 22a of the seal member SL4a in the second embodiment, the end portion that is not connected to the central seal portion 21a is thicker than the portion that is connected to the central seal portion 21a, and the anode-side separator 50 and In contact. In other words, the peripheral seal portion 22a is formed in an approximately L shape, and a gap G is provided between the peripheral seal portion 22a and the anode-side separator 50 on both sides of the central seal portion 21a. However, the gap G may be omitted, and a shape in which a seal member exists also in the gap G may be adopted. Even in this configuration, as in the first embodiment, sufficient sealing performance can be ensured without the central seal portion 21 a functioning to seal between the single cells 140 riding on the outer peripheral inclined wall 81. In addition, when the internal pressure is extremely large, the peripheral edge seal portion 22a, which is partly thicker than the periphery seal portion 22 on the outer periphery side of the seal member SL4 in the first embodiment, is compressed by the outer peripheral inclined wall 81. This makes it difficult to deform. Thereby, it becomes easy to stop the movement of the seal member SL4a by the peripheral seal portion 22a on the outer peripheral side, the central seal portion 21a becomes difficult to ride on the outer peripheral inclined wall 81, and the sealing performance can be further improved. The maximum thickness of the peripheral seal portion 22a of the seal member SL4a is preferably 20% or less of the clearance CL between the cathode separator 40 and the anode separator 50 of the other single cell 140. By doing so, the peripheral edge seal portion 22a on the outer peripheral side is pressed against the outer peripheral inclined wall 81, and when the thickness of the peripheral seal portion 22a on the outer peripheral side further increases due to deformation, the portion hits the anode separator 50. Since the cathode separator 40 of the other single cell 140 is not pressed, the sealing performance is not excessively lowered. In the second embodiment, only the peripheral seal portion 22a on the outer peripheral side of the seal member SL4a may have a thickened portion.

C. Third embodiment:
FIG. 6 is an explanatory view showing a cross section of the seal member SL4b in the third embodiment. The only difference from the second embodiment shown in FIG. 5 is that the corners Ea and Eb of the peripheral seal portion 22b are chamfered, and the other configuration is the same as that of the second embodiment. The description is omitted.

  FIG. 6A is a cross-sectional view when an internal pressure (open arrow) is applied to the seal member SL4b in a state where the cathode-side separator 40 of another unit cell 140 that contacts the anode-side separator 50 is displaced. . FIG. 6B shows a similar state when the corners Ea and Eb of the peripheral seal portion 22b of the seal member SL4b are not chamfered. When the sealing member SL4b moves to the outer peripheral inclined wall 81 due to the internal pressure, if the corner Eb is not chamfered, the corner Eb is pressed against the cathode separator 40 of the other single cell 140, and at the same time, the reaction force (A white arrow in FIG. 6B) acts on the cathode separator 40 of the other single cell 140. For this reason, the pressure which the center sealing part 21b of sealing member SL4b receives from the cathode side separator 40 of the other single cell 140 reduces, and sealing performance falls. On the other hand, as shown in FIG. 6A, if the corners Ea and Eb of the peripheral seal portion 22b of the seal member SL4b are chamfered, the cathode side of the other single cell 140 that hits the anode-side separator 50 will be described. Even if the separator 40 is displaced, a sufficient sealing property can be secured. In the third embodiment, only the corner Eb of the outer peripheral side peripheral seal portion 22b may be chamfered.

D. Fourth embodiment:
FIG. 7 is an enlarged schematic plan view showing the vicinity of the oxidant gas outlet manifold 74 in the fourth embodiment. The difference from the first embodiment shown in FIG. 3 is that adjacent portions of the seal member SL4c and the seal member SL5c, specifically, the adjacent peripheral seal portion 22c and the peripheral seal portion 24c are integrally connected. Since only the points are the same, the configuration other than this is the same as that of the first embodiment, and therefore illustration and description thereof are omitted. For convenience of illustration, the portion of the seal member in FIG. 7 is indicated by hatching.

  FIG. 8 is an explanatory view showing a cross section of the seal members SL4c and SL5c shown in FIG. Fig.8 (a) is explanatory drawing which shows BB cross section of sealing member SL4c. FIG. 8B is an explanatory view showing a CC cross section of the seal member SL5c. The cross section BB in FIG. 8A has a portion connected to the seal member SL5c, which is disposed at a specific corner portion located on the outer peripheral side of the anode separator 50 among the four corner portions of the oxidant gas outlet manifold 74. The cross section of seal member SL4c is shown. The CC cross section in FIG. 8B shows a cross section of the seal member SL5c that does not have a portion connected to the seal member SL4c. The cross section of the seal member SL4c that does not have a portion connected to the seal member SL5c is similar to the CC cross section. In the seal member SL4c, since the peripheral seal portion 22c arranged at the specific corner portion is connected to the seal member SL5c, the width Wb1 of the peripheral seal portion 22c on the outer peripheral side is connected to the seal member SL4c. It is configured to be larger than the width Wb of the peripheral seal portion 24c on the outer peripheral side of the seal member SL5c that is not provided.

  When the internal pressure is applied to the seal member SL4c, the seal member SL4c moves toward the outer peripheral inclined wall 81, and the outer peripheral peripheral edge seal portion 22c contacts the outer peripheral inclined wall 81 before the central seal portion 21c. Since the width Wb1 of the outer peripheral side peripheral seal portion 22c is larger than the width Ww of the outer peripheral side inclined wall 81, the movement of the seal member SL4c stops before the central seal portion 21c hits the outer peripheral side inclined wall 81. Thus, also in the fourth embodiment, sufficient sealing performance can be ensured as in the first embodiment. In addition, the width Wb1 of the peripheral seal portion 22c on the outer peripheral side of the seal member SL4c, which is disposed at the specific corner portion and has a portion connected to the seal member SL5c, does not have a portion connected to the seal member SL4c. It is configured to be larger than the width Wb of the peripheral seal portion 24c on the outer peripheral side of SL5c. Thereby, the movement of the seal member SL4c can be quickly stopped by the peripheral edge seal portion 22c on the outer peripheral side, the central seal portion 21c becomes difficult to ride on the outer peripheral inclined wall 81, and the sealing performance can be further improved. The shape feature of the seal member in the second embodiment or the third embodiment may be added to the shape feature of the seal member in the fourth embodiment. In all the embodiments described above, the inner peripheral inclined wall 83 may be omitted.

  The present invention is not limited to the above-described embodiment, and can be realized with various configurations without departing from the spirit of the present invention. For example, the technical features in the embodiments corresponding to the technical features in each embodiment described in the summary section of the invention are intended to solve part or all of the above-described problems, or one of the above-described effects. In order to achieve part or all, replacement or combination can be appropriately performed. Moreover, elements other than the elements described in the independent claims among the constituent elements in the respective embodiments described above are additional elements and can be omitted as appropriate.

DESCRIPTION OF SYMBOLS 10 ... Fuel cell system 21,21a, 21b, 21c ... Center seal part 22, 22a, 22b, 22c ... Perimeter seal part 24c ... Perimeter seal part 30 ... Membrane electrode assembly (MEA)
32 ... Frame member 40 ... Cathode side separator 42 ... Oxidant gas passage groove 50 ... Anode side separator 52 ... Fuel gas passage groove 54 ... Cooling medium passage groove 56 ... Dimple 62 ... Fuel gas inlet communication manifold 64 ... Fuel gas Outlet manifold 72 ... Oxidant gas inlet communication manifold 74 ... Oxidant gas outlet manifold 81 ... Outer peripheral side inclined wall 82 ... Cooling medium inlet communication manifold 83 ... Inner peripheral side inclined wall 84 ... Cooling medium outlet manifold 100 ... Fuel cell stack 110 ... End plate 120 ... Insulating plate 130 ... Current collecting plate 140 ... Single cell 150 ... Hydrogen tank 151 ... Shut valve 152 ... Regulator 153 ... Pipe 154 ... Discharge pipe 160 ... Air pump 161 ... Pipe 163 ... Discharge pipe 170 ... Radiator 171 ... Water pump 1 2 ... Piping 173 ... Piping 200 ... Cooling medium flow path CL ... Clearance Ea ... Corner Eb ... Corner G ... Gap SL1-SL5 ... Seal member SL4a, SL4b, SL4c ... Seal member SL5c ... Seal member X ... Stacking direction Y ... Vertical direction Z ... Horizontal direction

Claims (1)

A sealing structure having a sealing member installed on the surface of a separator of a single cell of a fuel cell and disposed between adjacent single cells,
The separator includes an outer peripheral side inclined wall formed on the outer peripheral side of the seal member so as to be inclined in the outer peripheral direction of the separator and toward the opposing separator ,
The seal member includes a center seal portion that seals between the single cells, and a peripheral seal portion that is formed integrally with the center seal portion on both sides of the center seal portion and has a smaller thickness than the center seal portion. Prepared,
The width of the peripheral seal portion provided on the outer peripheral side of the central seal portion is configured to be larger than the width of the outer peripheral inclined wall in a plan view of the separator.
Seal structure.

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