JP5265289B2 - Fuel cell stack - Google Patents

Description

  The present invention includes a plurality of electrolyte / electrode structures in which a pair of electrodes are disposed on both sides of an electrolyte, and a separator that is alternately stacked with each electrolyte / electrode assembly. A plurality of power generation units, each having a reaction gas flow path for flowing one reaction gas in the surface direction of the separator and a reaction gas communication hole for flowing the reaction gas in the stacking direction. The present invention relates to a fuel cell stack that is stacked by forming a cooling medium flow path.

  For example, in a polymer electrolyte fuel cell, an electrolyte membrane / electrode structure (MEA) in which an anode side electrode and a cathode side electrode are disposed on both sides of an electrolyte membrane made of a polymer ion exchange membrane is provided by a pair of separators. The unit cell is sandwiched. This type of fuel cell is normally used as a fuel cell stack by stacking a predetermined number of unit cells.

  In the above fuel cell, a fuel gas channel (reactive gas channel) for flowing fuel gas is provided in the surface of one separator so as to face the anode side electrode, and in the surface of the other separator, An oxidant gas flow path (reaction gas flow path) for flowing an oxidant gas is provided facing the cathode side electrode. Further, between the separators, a cooling medium flow path for flowing the cooling medium is provided along the surface direction of the separator.

  By the way, the fuel cell stack may adopt a so-called thinning cooling structure in which a cooling medium flow path is formed between a predetermined number of unit cells. In a fuel cell having this type of thinning cooling structure, for example, as disclosed in Patent Document 1 shown in FIG. 9, a separator 1, a cell 2, a separator 3, a cell 2 and a separator 4 are laminated.

  In the cell 2, the fuel electrode 2b and the air electrode 2c are disposed on both surfaces of the solid polymer electrolyte membrane 2a. A fuel gas passage 5 a is formed between the separator 1 and one cell 2, and an oxidant gas passage 6 a is formed between the separator 3 and the one cell 2. A fuel gas passage 5 b is formed between the separator 3 and the other cell 2, and an oxidant gas passage 6 b is formed between the separator 4 and the other cell 2. A cooling water passage 7 is formed between the separators 1 and 4 adjacent to each other.

JP 2002-289223 A

  In the fuel cell, the cooling water passage 7 is provided adjacent to the fuel gas passage 5a, and the cooling water passage 7 is provided adjacent to the oxidant gas passage 6b. On the other hand, the fuel gas passage 5 b and the oxidant gas passage 6 a are provided adjacent to each other and are separated from the cooling water passage 7.

  For this reason, the fuel gas passage 5a has a lower temperature than the fuel gas passage 5b, and the oxidant gas passage 6b has a lower temperature than the oxidant gas passage 6a. Accordingly, water generated during power generation by the fuel cell is likely to condense in the fuel gas passage 5a and the oxidant gas passage 6b having a low temperature. Thereby, in the fuel gas passage 5a and the oxidant gas passage 6b, there is a problem that the flow of the fuel gas and the oxidant gas is hindered by the generated water, and stable power generation is not performed.

  The present invention is a fuel cell having such a thin-out cooling structure, and can easily discharge generated water in the reaction gas flow path with a simple and economical configuration, and can stably perform stable power generation. An object is to provide a fuel cell stack.

The present invention includes a plurality of electrolyte electrode structure is disposed a pair of electrodes on both sides of the electrolyte, and a separator are alternately stacked and the electrolyte electrode assemblies, the fuel gas side of the separator a fuel gas passage for flowing direction, with a plurality of power generating units and fuel gas passage for circulating the fuel gas in the stacking direction is formed, it is laminated to form a cooling medium flow path between the power generating unit The present invention relates to a fuel cell stack.

The fuel cell stack is provided with a communication passage portion that communicates the fuel gas flow path and the fuel gas communication hole, and the pressure loss of the first communication passage portion that is disposed close to the cooling medium flow path is caused by the cooling medium. The pressure loss is set to be smaller than the pressure loss of the second communication path portion that is disposed away from the flow path.

Further, the communication passage portion includes a hole extending through the separator, the first hole of the first communication passage portion, the setting opening shape is larger than the second hole of the second communication passage portion It is preferred that

Furthermore, the communication path part has a connection path provided in the separator, and the first connection path of the first communication path part is at least in the width direction or deeper than the second connection path of the second communication path part . It is preferable that the vertical dimension is set large.

Furthermore, the communication path part has a connection path provided in the separator, and the first connection path of the first communication path part has a larger cross-sectional area than the second connection path of the second communication path part . Or it is preferable to set to short length.

According to the present invention, the pressure loss of the first communication path portion adjacent to the cooling medium flow path is set to be smaller than the pressure loss of the second communication path portion separated from the cooling medium flow path. The flow path resistance of the communication path portion is reduced. Therefore, the fuel gas can easily flow through the first communication passage portion, and the generated water condensed in the fuel gas flow path on the low temperature side can be discharged well and reliably, and stable power generation can be reliably performed. It becomes possible.

  FIG. 1 is an exploded perspective view of a main part of a power generation unit 12 constituting a fuel cell stack 10 according to a first embodiment of the present invention.

  As shown in FIGS. 2 and 3, the fuel cell stack 10 is configured by stacking a plurality of power generation units 12 along the horizontal direction (arrow A direction). The power generation unit 12 includes a first separator 14, a first electrolyte membrane / electrode structure (electrolyte / electrode structure) (MEA) 16 a, a second separator 18, a second electrolyte membrane / electrode structure 16 b, and a third separator 20. Provide. The power generation unit 12 can also include three or more MEAs and four or more separators. At that time, the MEA and the separator are alternately stacked.

  The 1st separator 14, the 2nd separator 18, and the 3rd separator 20 are comprised, for example with the steel plate, the stainless steel plate, the aluminum plate, the plating treatment steel plate, or the metal plate which gave the surface treatment for anticorrosion to the metal surface. The 1st separator 14, the 2nd separator 18, and the 3rd separator 20 have cross-sectional uneven | corrugated shape by pressing a metal thin plate into a waveform. In addition, you may comprise the 1st separator 14, the 2nd separator 18, and the 3rd separator 20 with a carbon separator, for example.

  As shown in FIGS. 1 and 2, the first electrolyte membrane / electrode structure 16a is set to have a smaller surface area than the second electrolyte membrane / electrode structure 16b. The first and second electrolyte membrane / electrode structures 16a and 16b include, for example, a solid polymer electrolyte membrane 22 in which a perfluorosulfonic acid thin film is impregnated with water, and an anode side sandwiching the solid polymer electrolyte membrane 22 The electrode 24 and the cathode side electrode 26 are provided. The anode side electrode 24 constitutes a so-called stepped MEA having a smaller surface area than the cathode side electrode 26.

  The anode side electrode 24 and the cathode side electrode 26 are uniformly coated on the surface of the gas diffusion layer 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. And an electrode catalyst layer (not shown) formed. The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 22.

  As shown in FIG. 1, the upper end edge (in the direction of arrow C) in the long side direction of the power generation unit 12 communicates with each other in the direction of arrow A to oxidize for supplying an oxidant gas, for example, an oxygen-containing gas. An agent gas inlet communication hole 30a and a fuel gas inlet communication hole 32a for supplying a fuel gas, for example, a hydrogen-containing gas, are provided.

  A lower end edge of the power generation unit 12 in the long side direction (arrow C direction) communicates with each other in the direction of arrow A to discharge the fuel gas outlet communication hole 32b for discharging the fuel gas, and to discharge the oxidant gas. The oxidant gas outlet communication hole 30b is provided.

  At one edge of the power generation unit 12 in the short side direction (arrow B direction), there is provided a cooling medium inlet communication hole 34a that communicates with each other in the direction of arrow A and supplies a cooling medium. A cooling medium outlet communication hole 34b for discharging the cooling medium is provided at the other end edge in the short side direction.

  On the surface 14a of the first separator 14 facing the first electrolyte membrane / electrode structure 16a, for example, a first fuel gas channel (reactive gas channel) 36 having a plurality of grooves extending in the direction of arrow C is provided. It is done. The first fuel gas channel 36 communicates with the fuel gas inlet communication hole 32a and the fuel gas outlet communication hole 32b via the first communication passage portions 38a and 38b.

  As shown in FIGS. 1 and 4, the first communication passage portion 38 a is provided on the surface 14 b opposite to the surface 14 a and is connected to the fuel gas inlet communication holes 32 a and the first separator 14. And a plurality of through holes 42 a communicating with the connecting passage 40 a and the first fuel gas passage 36. Similarly, the first communication passage portion 38b is provided on the surface 14b and communicates with the fuel gas outlet communication hole 32b. The first communication passage portion 38b penetrates the first separator 14 in the stacking direction and the connection passage 40b and the first connection passage 40b. A plurality of through holes 42 b communicating with one fuel gas flow path 36.

  A part of the cooling medium flow path 44 that connects the cooling medium inlet communication hole 34 a and the cooling medium outlet communication hole 34 b is formed on the surface 14 b of the first separator 14.

  As shown in FIG. 1, the surface 18a of the second separator 18 facing the first electrolyte membrane / electrode structure 16a is connected to the oxidant gas inlet communication hole 30a and the oxidant gas outlet communication hole 30b. An agent gas channel 46 is formed. The first oxidizing gas channel 46 has a plurality of grooves extending in the direction of arrow C.

  On the surface 18b of the second separator 18 facing the second electrolyte membrane / electrode structure 16b, for example, a second fuel gas channel (reactive gas channel) 48 having a plurality of grooves extending in the direction of arrow C is provided. It is done. The second fuel gas flow channel 48 communicates with the fuel gas inlet communication hole 32a and the fuel gas outlet communication hole 32b via the second communication passage portions 50a and 50b.

  As shown in FIGS. 1 and 5, the second communication passage portion 50a penetrates the second separator 18 in the stacking direction and the plurality of connection passages 52a provided on the surface 18a and communicating with the fuel gas inlet communication hole 32a. And a plurality of through holes 54 a communicating with the connecting passage 52 a and the second fuel gas passage 48. Similarly, the second communication passage portion 50b is provided on the surface 18a and communicates with the fuel gas outlet communication hole 32b, and the second separator 18 passes through the second separator 18 in the stacking direction. 2 having a plurality of through holes 54 b communicating with the fuel gas channel 48.

  The through hole 42a of the first communication passage portion 38a has a larger opening shape than the through hole 54a of the second communication passage portion 50a. That is, the opening diameter D1 of the through hole 42a is larger than the opening diameter D2 of the through hole 54a. Is also set to a large diameter (see FIGS. 2, 4 and 5). Similarly, the through hole 42b of the first communication passage portion 38b has a larger opening shape than the through hole 54b of the second communication passage portion 50b, that is, has a large diameter.

  As shown in FIG.4 and FIG.5, the dimension of the width direction of the connection path 40a of the 1st communication path part 38a is set larger than the connection path 52a of the 2nd communication path part 50a. The connection path 40b of the first communication path portion 38b is set to have a larger dimension in the width direction than the connection path 52b of the second communication path portion 50b.

  As shown in FIG. 1, the second oxidation that connects the oxidant gas inlet communication hole 30 a and the oxidant gas outlet communication hole 30 b to the surface 20 a of the third separator 20 facing the second electrolyte membrane / electrode structure 16 b. An agent gas channel 56 is formed. The second oxidizing gas channel 56 has a plurality of grooves extending in the direction of arrow C. A part of the cooling medium flow path 44 is formed on the surface 20 b of the third separator 20.

  As shown in FIGS. 1, 2, and 4, the first seal member 60 is integrally formed on the surfaces 14 a and 14 b of the first separator 14 around the outer peripheral edge of the first separator 14. As shown in FIGS. 1, 2, and 5, a second seal member 62 is integrally formed on the surfaces 18 a and 18 b of the second separator 18 around the outer peripheral edge of the second separator 18. The third seal member 64 is integrally formed on the surfaces 20a and 20b of the third separator 20 around the outer peripheral edge of the third separator 20 (see FIGS. 1 and 2).

  When the power generation units 12 are stacked on each other, the first power generation unit 12 and the third separator 20 included in the other power generation unit 12 extend in the direction of the arrow B. A cooling medium flow path 44 is formed (see FIGS. 1 and 3).

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

  First, as shown in FIG. 1, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas inlet communication hole 30a, and a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas inlet communication hole 32a. Further, a cooling medium such as pure water, ethylene glycol, or oil is supplied to the cooling medium inlet communication hole 34a.

  Therefore, the oxidant gas is introduced from the oxidant gas inlet communication hole 30 a into the first oxidant gas flow path 46 of the second separator 18 and the second oxidant gas flow path 56 of the third separator 20. The oxidant gas moves in the direction of arrow C (the direction of gravity) along the first oxidant gas flow path 46 and is supplied to the cathode side electrode 26 of the first electrolyte membrane / electrode structure 16a. It moves in the direction of arrow C along the oxidant gas flow path 56 and is supplied to the cathode electrode 26 of the second electrolyte membrane / electrode structure 16b.

  On the other hand, as shown in FIGS. 2 and 4, the fuel gas is supplied from the fuel gas inlet communication hole 32a to the connection path 40a constituting the first communication path portion 38a of the first separator 14, and passes through the through hole 42a. Move to the surface 14a side. For this reason, the fuel gas moves in the direction of gravity (arrow C direction) along the first fuel gas flow path 36 communicating with the through hole 42a, and is supplied to the anode side electrode 24 of the first electrolyte membrane / electrode structure 16a. Is done.

  Further, as shown in FIGS. 2 and 5, the fuel gas is supplied from the fuel gas inlet communication hole 32a to the connection passage 52a constituting the second communication passage portion 50a of the second separator 18, and passes through the through hole 54a. Move to the surface 18b side. Therefore, the fuel gas moves in the gravity direction (arrow C direction) along the second fuel gas flow path 48 communicating with the through hole 54a, and is supplied to the anode side electrode 24 of the second electrolyte membrane / electrode structure 16b. The

  Thus, in the first and second electrolyte membrane / electrode structures 16a and 16b, the oxidant gas supplied to the cathode side electrode 26 and the fuel gas supplied to the anode side electrode 24 are within the electrode catalyst layer. It is consumed by electrochemical reaction to generate electricity.

  Next, the oxidant gas consumed by being supplied to the cathode-side electrodes 26 of the first and second electrolyte membrane / electrode structures 16a and 16b is discharged in the direction of arrow A along the oxidant gas outlet communication hole 30b. The

  As shown in FIG. 4, the fuel gas consumed by being supplied to the anode side electrode 24 of the first electrolyte membrane / electrode structure 16a passes through the through-hole 42b constituting the first communication passage portion 38b and forms the first separator. 14 surface 14b side. The fuel gas led out to the surface 14b side is discharged to the fuel gas outlet communication hole 32b through the connection path 40b.

  Further, as shown in FIG. 5, the fuel gas consumed by being supplied to the anode-side electrode 24 of the second electrolyte membrane / electrode structure 16b passes through the through-holes 54b constituting the second communication passage portion 50b. The two separators 18 are led out to the surface 18a side. The fuel gas led out to the surface 18a side is discharged to the fuel gas outlet communication hole 32b through the connection path 52b.

  On the other hand, the cooling medium supplied to the cooling medium inlet communication hole 34 a is the cooling formed between the first separator 14 constituting one power generation unit 12 and the third separator 20 constituting the other power generation unit 12. After being introduced into the medium flow path 44, it flows in the direction of arrow B. The cooling medium cools the first and second electrolyte membrane / electrode structures 16a and 16b, and then is discharged into the cooling medium outlet communication hole 34b.

  In this case, in the first embodiment, as shown in FIG. 3, the first fuel gas passage 36 is adjacent to the cooling medium passage 44, while the second fuel gas passage 48 is the first oxidant gas. Adjacent to the flow path 46 and spaced from the cooling medium flow path 44. As a result, the first fuel gas channel 36 is likely to be colder than the second fuel gas channel 48.

  Therefore, as shown in FIGS. 4 and 5, the through hole 42a of the first communication passage portion 38a is set to have a larger opening shape than the through hole 54a of the second communication passage portion 50a, and the first communication passage portion. The through hole 42b of 38b is set to have a larger opening shape than the through hole 54b of the second communication passage portion 50b.

  For this reason, the pressure loss of the first communication passage portions 38a and 38b adjacent to the cooling medium flow path 44 is set smaller than the pressure loss of the second communication passage portions 50a and 50b spaced from the cooling medium flow path 44. Therefore, the fuel gas easily flows through the first communication passage portions 38a and 38b, and the generated water condensed in the first fuel gas flow path 36 on the low temperature side can be discharged well and reliably, and stable power generation can be achieved. The effect that it becomes possible to perform reliably is acquired.

  The connection path 40a of the first communication path portion 38a is set to have a larger dimension in the width direction than the connection path 52a of the second communication path portion 50a, while the connection path 40b of the first communication path portion 38b is The dimension in the width direction is set to be larger than that of the connecting path 52b of the two communicating path portions 50b. Thereby, the pressure loss of the first communication passage portions 38a, 38b on the low temperature side is set smaller than the pressure loss of the second communication passage portions 50a, 50b on the high temperature side, and the drainage can be easily improved.

  FIG. 6 is an exploded perspective view of a main part of the power generation unit 72 constituting the fuel cell stack 70 according to the second embodiment of the present invention. 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 power generation unit 72 includes a first separator 74, a first electrolyte membrane / electrode structure (electrolyte / electrode structure) 76a, a second separator 78, a second electrolyte membrane / electrode structure 76b, and a third separator 80.

  As shown in FIGS. 6 and 7, a first fuel gas passage 36 is provided on the surface 14a side of the first separator 74, and the first fuel gas passage 36, the fuel gas inlet communication hole 32a, and the fuel are provided. The gas outlet communication hole 32b communicates with the first communication passage portions 82a and 82b. The first communication passage portions 82a and 82b have a plurality of connection passages 84a and 84b provided on the surface 14a. The connection paths 84 a and 84 b are formed between the protrusions that are integrally formed with the first seal member 60.

  As shown in FIGS. 6 and 8, a second fuel gas passage 48 is provided on the surface 18b side of the second separator 78, and the second fuel gas passage 48, the fuel gas inlet communication hole 32a, and the fuel are provided. The gas outlet communication hole 32b communicates with the second communication passage portions 86a and 86b. The second communication passage portions 86a and 86b have a plurality of connection passages 88a and 88b provided on the surface 18b. The connection paths 88 a and 88 b are formed between the protrusions that are integrally formed with the second seal member 62.

  The connection path 84a of the first communication path portion 82a has a larger dimension in the width direction than the connection path 88a of the second communication path section 86a. That is, the width dimension h1 of the connection path 84a is the width dimension of the connection path 88a. It is set wider than h2. Similarly, the connecting path 84b of the first communicating path portion 82b is set to have a larger dimension in the width direction than the connecting path 88b of the second communicating path portion 86b.

  In the second embodiment configured as described above, the connection path 84a of the first communication path portion 82a is set to have a larger dimension in the width direction than the connection path 88a of the second communication path section 86a, and the first The connecting path 84b of the communicating path portion 82b is set to have a larger dimension in the width direction than the connecting path 88b of the second communicating path portion 86b.

  Thereby, the pressure loss of the first communication passage portions 82a and 82b adjacent to the cooling medium flow path 44 is set to be smaller than the pressure loss of the second communication passage portions 86a and 86b separated from the cooling medium flow path 44. Accordingly, the fuel gas can easily flow through the first communication passage portions 82a and 82b, and the generated water (particularly, the condensed generated water) in the first fuel gas flow path 36 on the low temperature side can be discharged well and reliably. Thus, the same effects as those of the first embodiment can be obtained, such as enabling stable power generation.

  In the second embodiment, the connecting passages 84a and 84b of the first communicating passage portions 82a and 82b are set to have a larger dimension in the width direction than the connecting passages 88a and 88b of the second communicating passage portions 86a and 86b. However, it is not limited to this. For example, the connecting passages 84a and 84b of the first communicating passage portions 82a and 82b may be set to have a larger dimension in the depth direction than the connecting passages 88a and 88b of the second communicating passage portions 86a and 86b.

  Moreover, the connection paths 84a and 84b of the first communication path portions 82a and 82b may be set to have a larger or shorter cross-sectional area than the connection paths 88a and 88b of the second communication path portions 86a and 86b.

It is a principal part disassembled perspective explanatory drawing of the electric power generation unit which comprises the fuel cell stack which concerns on the 1st Embodiment of this invention. FIG. 2 is a sectional view of the fuel cell stack taken along line II-II in FIG. 1. FIG. 3 is a cross-sectional explanatory view of the fuel cell stack. It is front explanatory drawing of the 1st separator which comprises the said electric power generation unit. It is front explanatory drawing of the 2nd separator which comprises the said electric power generation unit. It is a principal part disassembled perspective explanatory drawing of the electric power generation unit which comprises the fuel cell stack concerning the 2nd Embodiment of this invention. It is front explanatory drawing of the 1st separator which comprises the said electric power generation unit. It is front explanatory drawing of the 2nd separator which comprises the said electric power generation unit. It is explanatory drawing of the fuel cell which has the conventional thinning cooling structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 70 ... Fuel cell stack 12 ... Electric power generation unit 14, 18, 20, 74, 78, 80 ... Separator 16a, 16b, 76a, 76b ... Electrolyte membrane electrode structure 22 ... Solid polymer electrolyte membrane 24 ... Anode side electrode 26 ... Cathode side electrode 30a ... Oxidant gas inlet communication hole 30b ... Oxidant gas outlet communication hole 32a ... Fuel gas inlet communication hole 32b ... Fuel gas outlet communication hole 34a ... Cooling medium inlet communication hole 34b ... Cooling medium outlet communication hole 36 48 ... Fuel gas passages 38a, 38b, 50a, 50b, 82a, 82b, 86a, 86b ... Communication passages 40a, 40b, 52a, 52b, 84a, 84b, 88a, 88b ... Connection passages 42a, 42b, 54a, 54b ... through hole 44 ... cooling medium flow path 46, 56 ... oxidant gas flow path

Claims (5)

Fuel and a plurality of electrolyte electrode structure is disposed a pair of electrodes on both sides of the electrolyte, and a separator are alternately stacked and the electrolyte electrode assemblies, flow of fuel gas in the direction of the face of the separator A fuel cell stack comprising a plurality of power generation units in which a gas flow path and a fuel gas communication hole for flowing the fuel gas in the stacking direction are formed, and a cooling medium flow path is formed between the power generation units and stacked. There,
A communication path portion that communicates the fuel gas flow path and the fuel gas communication hole is provided,
The pressure loss of the first communication passage portion arranged close to the cooling medium flow path is set to be smaller than the pressure loss of the second communication passage portion arranged apart from the cooling medium flow path. A fuel cell stack. 2. The fuel cell stack according to claim 1, wherein the communication path portion has a hole portion that penetrates the separator,
The fuel cell stack, wherein the first hole portion of the first communication passage portion is set to have a larger opening shape than the second hole portion of the second communication passage portion. The fuel cell stack according to claim 2, wherein the communication path portion includes a connection path provided in the separator,
The first connection path of the first communication path portion is set to have a larger dimension in the width direction than the second connection path of the second communication path portion,
While the first connection path connects the fuel gas communication hole and the first hole on the back side of the fuel gas flow path,
The fuel cell stack, wherein the second connection path connects the fuel gas communication hole and the second hole on the back side of the fuel gas flow path. The fuel cell stack according to claim 1 Symbol placement, the communicating passage portion has a connecting passage provided in the separator,
The fuel is characterized in that the first connecting path of the first communication path portion is set to have at least a width or depth dimension larger than that of the second connection path of the second communication path portion . Battery stack. The fuel cell stack according to claim 1 Symbol placement, the communicating passage portion has a connecting passage provided in the separator,
The fuel cell stack, wherein the first connection path of the first communication path portion has a cross-sectional area larger or shorter than that of the second connection path of the second communication path portion.

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