JP2017201617A - Gas channel forming plate for fuel cell and fuel cell stack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas channel forming plate for a fuel cell and a fuel cell stack, capable of efficiently draining water into water channels through communication passages.SOLUTION: A gas channel forming plate 22 configures a first separator 20 for a single cell between a membrane electrode assembly 13 and a flat separator 21. The gas channel forming plate 22 includes: a plurality of gas channels 25 arranged on a surface that faces the membrane electrode assembly 13; water channels 26 each formed on the back side of an outside protrusion 24 located between an adjacent pair of the gas channels 25; a plurality of communication passages 27 that communicate the gas channels 25 and the water channels 26 to each other; and guide portions 28 having a form protruding from the bottom surface of each gas channel 25. The guide portions 28 are formed to have such a form that the protruding amount from the bottom surface increases toward the downstream side. The guide portions 28 have such a form that the upstream edge 273 of each communication passage 27 is arranged in a range in which, in the velocity vector of the gas flowing in the gas channel 25, the directional component directed from a membrane electrode assembly 13 side toward a flat separator 21 side has a positive value.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a fuel cell gas flow path forming plate interposed between a membrane electrode assembly and a plate-like separator, and a fuel cell stack formed by stacking a plurality of the same cells.

For example, a polymer electrolyte fuel cell includes a fuel cell stack formed by stacking a plurality of single cells having a structure in which a membrane electrode assembly is sandwiched between a pair of separators.
As such a separator, there is one having a flat flat separator and a gas flow path forming plate interposed between the flat separator and the membrane electrode assembly (see, for example, Patent Document 1).

  In the gas flow path forming plate described in Patent Document 1, a plurality of concave grooves are arranged at intervals on the surface facing the membrane electrode assembly. This concave groove functions as a gas flow path for circulating a gas (fuel gas or oxidant gas) supplied to the inside of the single cell (specifically, to the membrane electrode assembly). Further, protrusions are formed between two adjacent gas flow paths in the gas flow path forming plate, and the back surfaces of these protrusions are concave grooves. And this ditch | groove functions as a water flow path for discharging | emitting the water which generate | occur | produces inside a single cell at the time of electric power generation to the exterior of a single cell. Further, a through hole (communication path) that connects the gas flow path and the water flow path is formed in the protrusion.

  In such a fuel cell stack, water generated during power generation in the membrane electrode assembly flows into the water flow path through the communication path of the gas flow path forming plate. And the water which flowed in in the water flow path is pushed away by the flow pressure of the gas flowing through the inside of the water flow path, and is discharged outside the water flow path.

JP 2014-167860 A

  The gas flow path forming plate described above has a structure capable of draining into the water flow path only at the portion where the communication path is formed. Therefore, although the water generated in the vicinity of the communication path can be quickly discharged to the water flow path, the water generated in a portion away from the communication path takes time to discharge to the water flow path.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a gas flow path forming plate for a fuel cell and a fuel cell stack that can efficiently drain water into the water flow path through the communication path. There is.

  A gas flow path forming plate for a fuel cell for solving the above problem is a gas flow path forming plate of a single cell of a fuel cell interposed between a membrane electrode assembly and a plate-shaped separator, A plurality of concave groove-shaped gas passages arranged so as to be arranged at intervals on a surface facing the membrane electrode assembly, and a recess formed on the back surface of the ridge located between the adjacent gas passages A groove-shaped water flow path, a plurality of communication paths that are formed at positions spaced apart in the direction in which the protrusions extend in the protrusion, and communicate with the gas flow path and the water flow path; and the gas flow An inner wall surface of the gas flow path has a shape projecting inward of the gas flow path in a form in which a passage cross-sectional area of the path is partially narrowed, and the gas flow paths in the plurality of communication paths are An end on the upstream side in the flow direction of the flowing gas is the velocity vector of the gas. Comprising a guide portion is shaped to directional component from Kimaku electrode assembly side towards the separator side is disposed within the range of a positive value, the.

  In the above configuration, the cross-sectional area of the gas flow path (specifically, the portion sandwiched between the gas flow path forming plate and the membrane electrode assembly) in the portion where the guide portion is disposed is partially narrowed. Therefore, when the gas flow path passes through the portion where the guide portion is disposed, the gas flow includes a directional component from the bottom side (separator side) of the gas flow path toward the membrane electrode assembly side. The flow rate is increased. Therefore, the water around the guide portion can be swept away by such a gas flow and collected around the communication path formed in the ridge.

  In addition, in the above configuration, the passage cross-sectional area of the gas flow path suddenly expands at the downstream end (hereinafter simply referred to as “downstream”) of the gas flow direction in the guide portion. This gas diffuses in the gas flow path, and the flow of the gas includes a directional component from the membrane electrode assembly side to the separator side of the gas flow path. In the above configuration, at least a part of the plurality of communication passages includes a portion in which the gas flow includes a directional component from the membrane electrode assembly side to the separator side, that is, a directional component toward the opening of the communication passage formed in the protrusion. Placed in the part. Therefore, by using such a gas flow, the water collected around the communication path can be introduced into the communication path and discharged into the water flow path.

Thus, according to the said structure, the drainage to the water flow path through a communicating path can be performed efficiently.
In the gas flow path forming plate for a fuel cell, the end of the guide portion on the downstream side in the flow direction and the end portion on the upstream side in the flow direction of the plurality of communication paths have the same position in the flow direction. It is preferable.

  According to the above configuration, since the gas flow toward the separator side after passing through the arrangement portion of the guide portion easily flows into the plurality of communication passages, the communication passages can be effectively utilized by using the entire openings of the communication passages. The surrounding water can be introduced.

In the fuel cell gas flow path forming plate, it is preferable that the guide portion has an inclined surface that is inclined in such a shape that the protruding amount of the inner wall surface increases toward the downstream side in the flow direction.
According to the above configuration, the gas smoothly flows along the inclined surface, so that an increase in pressure loss due to the provision of the guide portion can be suppressed.

In the gas flow path forming plate for a fuel cell, the gas flow path forming plate is preferably a plate material having a concave-convex cross section in a direction orthogonal to a direction in which the gas flow path extends.
According to the above configuration, the plate material having the concavo-convex shape is made of gas so that each concave groove on one surface of the plate material having the concavo-convex shape is used as a gas flow path and each groove on the other surface is a water flow path. A gas flow path forming plate having a flow path and a water flow path can be obtained.

  In the gas flow path forming plate for a fuel cell, the plurality of communication passages and one guide portion constitute one functional portion that functions independently, and a plurality of the functional portions are provided at intervals. It is preferable.

According to the said structure, the efficient drainage to the water flow path by a function part can be performed over the wide range inside a single cell.
A fuel cell stack for solving the above problems is a fuel cell stack in which a plurality of single cells are stacked, and the single cell includes a membrane electrode assembly, a plate-shaped separator, and the membrane electrode assembly. And the fuel cell gas flow path forming plate interposed between the separators.

  ADVANTAGE OF THE INVENTION According to this invention, the drainage to the water flow path through a communicating path can be performed efficiently.

Sectional drawing which shows one Embodiment of a gas flow path formation board and a fuel cell stack. The perspective view of the 1st separator of the embodiment. The elements on larger scale of FIG. It is sectional drawing of a 1st separator, (a) is sectional drawing along the 4A-4A line in FIG. 5, (b) is sectional drawing along the 4B-4B line in FIG. Sectional drawing which shows the arrangement | positioning part of the guide part in a gas flow path, and its periphery. (A)-(d) is sectional drawing centering on a communicating path, Comprising: Explanatory drawing explaining the effect | action of embodiment. Sectional drawing which shows the arrangement | positioning part of the guide part in the gas flow path of other embodiment, and its periphery. Sectional drawing which shows the arrangement | positioning part of the guide part in the gas flow path of other embodiment, and its periphery. The schematic diagram which shows the planar structure of the separator of other embodiment. The schematic diagram which shows the planar structure of the separator of other embodiment.

Hereinafter, an embodiment of a fuel cell gas flow path forming plate and a fuel cell stack will be described.
As shown in FIG. 1, the fuel cell stack of the present embodiment has a structure in which a plurality of single cells 10 are stacked, and is built in a polymer electrolyte fuel cell. In FIG. 1, the upper unit cell 10 shows a cross-sectional shape cut at a position where water channels 26 and 36 described later are disposed, and the lower unit cell 10 includes gas channels 25 and 35 described later. The cross-sectional shape cut | disconnected in the position where is arrange | positioned is shown.

  Each of the plurality of single cells 10 includes a first frame 11 and a second frame 12 each having a square frame shape, and an outer edge portion of a known membrane electrode assembly 13 having a square sheet shape by the frames 11 and 12 is formed. It is pinched. The membrane electrode assembly 13 includes a solid polymer electrolyte membrane 14, a pair of electrode catalyst layers 15 and 16 sandwiching the solid polymer electrolyte membrane 14, and a shape covering the outer surfaces of the electrode catalyst layers 15 and 16. A multi-layer structure having a pair of gas diffusion layers 17 and 18 is formed.

  The membrane electrode assembly 13 is sandwiched between the first separator 20 and the second separator 30. The first separator 20 is in contact with the gas diffusion layer 17 on the cathode side (lower side in FIG. 1) of the membrane electrode assembly 13. The flat separator 21, the flat separator 21, and the membrane electrode assembly 13 are in contact with each other. And a gas flow path forming plate 22 interposed therebetween. The second separator 30 is in contact with the gas diffusion layer 18 on the anode side (upper side in FIG. 1) of the membrane electrode assembly 13. The flat separator 31 and the flat separator 31 and the membrane electrode assembly 13 And a gas flow path forming plate 32 interposed therebetween. The flat separators 21 and 31 and the gas flow path forming plates 22 and 32 are each formed of a metal plate material.

  Inside the single cell 10, a supply passage 41 for supplying an oxidant gas to a gas flow path 25 described later from an oxidant gas supply source (not shown), and an oxidant gas that has not been used for power generation are gas flowed. A discharge passage 42 for discharging to the outside of the passage 25 is defined by the first frame 11 and the flat separator 21.

  Further, inside the single cell 10, a supply passage 51 for supplying fuel gas from a fuel gas supply source (not shown) to a gas passage 35 to be described later, and a fuel passage that has not been used for power generation are supplied to the gas passage. A discharge passage 52 for discharging to the outside of 35 is defined by the second frame 12 and the flat separator 31.

  In the portion shown in FIG. 1, the gas flow path forming plate 32 of the second separator 30 has a shape that is vertically reversed and horizontally reversed with respect to the gas flow path forming plate 22 of the first separator 20. Therefore, in the following, the gas flow path forming plate 22 of the first separator 20 will be described in detail, while the gas flow path forming plate 32 of the second separator 30 will be described in each part of the gas flow path forming plate 22 of the first separator 20. The duplicated explanation is omitted by adding the code “3 *” obtained by adding “10” to the code “2 *”. In addition, the symbols “25 *”, “27 *”, and “28 *” are each given the symbols “35 *”, “37 *”, and “38 *” obtained by adding “100”, thereby omitting redundant explanation. To do.

Hereinafter, the structure of the gas flow path forming plate 22 will be described.
As shown in FIG. 2, the gas flow path forming plate 22 has a substantially corrugated cross section, and is formed by roll forming a single metal plate material such as a stainless steel plate.

  A plurality of inner ridges 23 extending in parallel to each other are formed on the surface (upper surface in FIG. 2) of the gas flow path forming plate 22 facing the membrane electrode assembly 13 (see FIG. 1). The top surface of 23 is in contact with the membrane electrode assembly 13. Further, a concave gas channel 25 is formed between two adjacent inner ridges 23. The gas flow path 25 mainly functions as a passage for circulating the oxidant gas.

  On the other hand, a plurality of outer ridges 24 extending in parallel to each other are formed on the surface (the lower surface in FIG. 2) facing the flat separator 21 of the gas flow path forming plate 22, and the top surfaces of these outer ridges 24 are It is in contact with the flat separator 21. Further, water channels 26 each having a groove shape are formed between the two outer ridges 24 adjacent to each other, that is, on the back surface of each inner ridge 23. Each water flow path 26 mainly functions as a passage for discharging water generated with power generation in the membrane electrode assembly 13.

  The gas flow path forming plate 22 is curved in the direction (hereinafter, the width direction W) orthogonal to the direction in which the inner ridge 23 and the outer ridge 24 extend, that is, the direction in which the gas flow path 25 extends (hereinafter, the extending direction L). Corrugated plate material.

  As shown in FIGS. 2 and 3, a plurality of ribs 271 having a shape extending in the width direction W are formed on the inner protrusion 23 of the gas flow path forming plate 22. Specifically, the gas flow path forming plate 22 is provided with a plurality of sets each including a pair of ribs 271 arranged at positions close to each other in the extending direction L. A set of such a pair of ribs 271 is arranged at equal intervals in the extending direction L. Each rib 271 partially shears a portion on the top surface side of each inner protrusion 23 when the gas flow path forming plate 22 is formed by roll forming a metal plate material along the width direction W. , By bending the sheared portion away from the top surface.

  FIG. 4A shows a cross-sectional shape of the gas flow path forming plate 22 at a portion where the rib 271 is not formed, and FIG. 4B shows a cross-sectional shape of the gas flow path forming plate 22 at a portion where the rib 271 is formed. .

  As shown in FIGS. 4A and 4B, the rib 271 protrudes into the water flow path 26. Therefore, the inside of the water channel 26 is blocked by the ribs 271, and the pressure loss of the oxidant gas in the water channel 26 increases accordingly. As shown in FIGS. 2 to 4, a plurality of ribs 271 are formed on the inner ridge 23 of the gas flow path forming plate 22, thereby connecting a plurality of gas flow paths 25 and water flow paths 26. A communication path 27 is formed. The shapes of the communication passages 27 are determined such that the pressure loss of the oxidant gas in the communication passage 27 is larger than the pressure loss of the oxidant gas in the gas flow path 25. For these reasons, in the portion where the gas flow path forming plate 22 is disposed, the oxidant gas mainly flows through the gas flow path 25 with a small pressure loss.

  As shown in FIGS. 1 to 5, the gas channel 25 is integrally formed with a plurality of guide portions 28 whose inner wall surfaces protrude toward the inside of the gas channel 25. These guide portions 28 are formed in a shape that protrudes from the bottom surface of the gas flow path 25 toward the top surface side (upper side in FIG. 5) of the inner protrusion 23. As shown in FIG. 2, each guide portion 28 is formed in the same shape, and is provided at a position adjacent to the pair of ribs 271 (communication path 27) of the inner ridge 23 in the width direction W. Therefore, each guide portion 28 is also provided at equal intervals in the extending direction L, like the pair of communication paths 27.

  As shown in FIG. 5, most of the protruding end surface of the guide portion 28 is from the bottom surface toward the downstream side in the flow direction of the oxidant gas flowing through the gas flow path 25 (hereinafter, simply “downstream side”). It is comprised by the inclined surface 281 inclined in the shape where the protrusion amount of becomes large. Only the portion in the vicinity of the downstream end portion 282 on the protruding end surface of the guide portion 28 is constituted by the flat surface 283 having the same amount of protrusion from the bottom surface. Thus, the amount of protrusion from the bottom surface of each guide portion 28 increases toward the downstream side. A communication hole 29 that connects the gas flow path 25 and the water flow path 26 is formed between the downstream end 282 of the guide portion 28 and the bottom surface of the gas flow path 25.

  In the present embodiment, the downstream end portion 282 of the guide portion 28 and the upstream side in the flow direction of the oxidant gas (hereinafter simply “upstream side”) of the pair of communication passages 27 (hereinafter simply “upstream side”) Each guide portion 28 is arranged so that the upstream end portion 273 of the passage 27) is at the same position in the flow direction of the oxidant gas (extending direction L). Each guide portion 28 rolls a metal plate material along the width direction W to form the gas flow path forming plate 22. When the gas flow path forming plate 22 is formed, a portion on the top surface side of each outer protrusion 24 (the bottom surface side of the gas flow path 25). Are partially sheared, and the sheared portion is bent in a direction away from the top surface. In the present embodiment, the pair of communication passages 27 and the one guide portion 28 adjacent to the communication passages 27 constitute one functional portion that functions independently, and this functional portion is the gas flow path forming plate 22. A plurality are provided at intervals.

Hereinafter, the operation of providing such a functional unit on the gas flow path forming plate 22 will be described.
As shown in the lower unit cell 10 in FIG. 1, when the fuel gas is supplied into the gas flow path 35 through the supply passage 51, the fuel gas flows into the gas diffusion layer 18 through the gas flow path 35. The fuel gas passes through the gas diffusion layer 18 and is diffused and supplied to the electrode catalyst layer 16. On the other hand, when the oxidant gas is supplied into the gas flow path 25 through the supply passage 41, the oxidant gas flows into the gas diffusion layer 17 through the gas flow path 25. The oxidizing gas passes through the gas diffusion layer 17 and is diffused and supplied to the electrode catalyst layer 15. When the fuel gas and the oxidant gas are supplied to the membrane electrode assembly 13 in this manner, power generation is performed by an electrochemical reaction in the membrane electrode assembly 13.

  During power generation in the membrane electrode assembly 13, water is generated inside the gas diffusion layer 17 on the cathode side (specifically, the interface with the electrode catalyst layer 15 and the vicinity thereof). In order to improve the power generation efficiency of the single cell 10, it is desirable that the water generated inside the gas diffusion layer 17 is quickly discharged to the water flow path 26.

  In the present embodiment, as shown in FIG. 5, the gas flow path 25 (specifically, the gas flow path forming plate 22 and the gas diffusion layer 17 are sandwiched in the arrangement portion of the guide portion 28 inside the single cell 10. ) Is narrower toward the downstream side (left side in FIG. 5). Therefore, when the oxidant gas passes through the portion where the guide portion 28 is disposed in the gas flow path 25, the flow of the oxidant gas flows from the bottom side (flat separator 21 side) of the gas flow path 25 to the membrane electrode assembly 13 side. And a flow rate of the oxidizing gas is increased. A part of the flow of the oxidant gas (flow indicated by an arrow F1 in FIG. 5) flows into the gas diffusion layer 17.

  Thus, the water WT inside the gas diffusion layer 17 is pushed away by the flow pressure of the oxidant gas that flows in, and the water WT inside the gas diffusion layer 17 flows into the downstream end 282 of the guide portion 28, that is, the communication passage 27. Collected in the vicinity of the arrangement portion. The water WT collected in this manner is drawn into the inside of the communication passage 27 opened at the top surface of the inner ridge 23 in contact with the gas diffusion layer 17 by capillary action.

  Further, in the present embodiment, since the communication passage 27 of the inner ridge 23 is open at a position adjacent to the downstream end 282 of the guide portion 28 in the gas flow path 25, the downstream end of the guide portion 28. The portion 282 has a structure in which the cross-sectional area of a passage portion (specifically, a portion including the gas flow path 25 and the communication passage 27) through which the oxidant gas passes rapidly increases. Therefore, the oxidant gas after passing through the portion where the guide portion 28 is disposed diffuses in the gas flow path 25, and the flow of the oxidant gas flows from the membrane electrode assembly 13 side of the gas flow path 25 to the flat separator 21. A direction component (downward component in FIG. 5) toward the side is included.

  Thus, in the present embodiment, the pair of communication passages 27 are within a range in which the directional component from the membrane electrode assembly 13 side toward the flat separator 21 side in the velocity vector of the oxidant gas flowing through the gas flow path 25 becomes a positive value. The shapes of the communication passage 27 and the guide portion 28 are determined so that the upstream end portion 273 is disposed. Thereby, at least a part of the pair of communication passages 27 is a communication passage formed in a portion in which the flow of the oxidant gas includes a directional component from the membrane electrode assembly 13 side toward the flat separator 21 side, that is, the inner protrusion 23. 27 is arranged in a portion including a direction component toward the opening. Therefore, a part of the flow of the oxidant gas after passing through the portion where the guide portion 28 is disposed is directed toward the inside of the communication passage 27. Using the flow of gas toward the inside of the communication path 27 (flow indicated by the arrow F2 in FIG. 5), the water WT collected around the communication path 27 in the gas diffusion layer 17 is converted into the interior of the communication path 27. Can be introduced.

  As shown in FIG. 6A, the water introduced into the communication path 27 forms water droplets S <b> 1 and S <b> 2 inside each of the pair of communication paths 27. Thereafter, when water is further introduced into the communication path 27 and the water droplets S1 and S2 grow, both the water droplets S1 and S2 are combined into one water droplet S3 as shown in FIG. 6B. In this way, the water droplets S3 come into contact with the ribs 271 as the water droplets combine or the combined water droplet S3 grows further. When the water droplet S3 reaches the gap between the pair of ribs 271 as shown in FIG. 6 (c), the water droplet S3 is drawn into the gap by capillary action as shown in FIG. 6 (d). It is introduced into the passage 26. In addition, when the water introduced into the water flow path 26 becomes water droplets and is moored on the rib 271, this water becomes priming water, and the water in the communication path 27 is guided into the water flow path 26 by capillary action. It becomes like this.

  As described above, according to the present embodiment, by providing the guide portion 28 on the gas flow path forming plate 22, the flow of the gas flowing in the gas flow path 25 is used to access the water flow path 26 through the communication path 27. Drainage can be performed efficiently.

  The water thus introduced into the water flow path 26 is pushed downstream by the flow pressure of the oxidant gas flowing through the water flow path 26 and discharged to the outside of the single cell 10 through the discharge passage 42. .

  As shown in FIG. 5, when the gas flow path forming plate 22 is provided with the guide portion 28, the bottom surface of the gas flow path 25 is located at a position adjacent to the downstream end 282 of the guide portion 28 in the gas flow path 25. A concave corner 251 that is recessed toward the side (the lower side in FIG. 5) is formed. Since the oxidant gas does not flow easily in the corner 251, when the water WT generated by the power generation in the membrane electrode assembly 13 flows into the gas flow path 25, the water stays in the corner 251. It's easy to do. In the present embodiment, a communication hole 29 that connects the gas flow path 25 and the water flow path 26 is formed in the corner 251. Therefore, the water that flows into the gas flow path 25 and reaches the corner 251 is drawn into the communication hole 29 by capillary action and is introduced into the water flow path 26.

  Further, during power generation in the membrane electrode assembly 13, water is generated in a portion on the anode side inside the single cell 10 (for example, inside the gas diffusion layer 18). In the present embodiment, the anode-side gas flow path forming plate 32 has the same structure as the cathode-side gas flow path forming plate 22. Therefore, the anode-side gas flow path 35 and the water flow path 36 also have the same effects as the cathode-side gas flow path 25 and the water flow path 26 described above.

As described above, according to the present embodiment, the following effects can be obtained.
(1) By providing the guide portions 28 and 38 on the gas flow path forming plates 22 and 32, drainage to the water flow paths 26 and 36 through the communication paths 27 and 37 can be performed efficiently.

  (2) The downstream end portions 282 and 382 of the guide portions 28 and 38 and the upstream end portions 273 and 373 of the upstream communication passages 27 and 37 of the pair of communication passages 27 and 37 are extended. The positions in the installation direction L are the same. Thereby, the internal structure of the unit cell 10 is a structure in which no space is formed between the downstream end portions 282 and 382 of the guide portions 28 and 38 in the extending direction L and the opening portions of the communication passages 27 and 37. Thus, the guide portions 28 and 38 and the opening portions of the communication passages 27 and 37 do not overlap in the extending direction L. Therefore, most of the oxidant gas flow (see the arrow F2 in FIG. 5) which is deflected after passing through the portions where the guide portions 28 and 38 are disposed and flows toward the inside of the communication passages 27 and 37 (see the arrow F2 in FIG. 5) The flow tends to flow into the communication passages 27 and 37. Accordingly, it is possible to introduce water around the communication passages 27 and 37 by effectively using the entire opening of the communication passages 27 and 37.

  (3) The protruding end surfaces of the guide portions 28 and 38 are constituted by inclined surfaces 281 and 381 and flat surfaces 283 and 383 having a shape in which the protruding amount increases toward the downstream side. Therefore, gas (oxidant gas or fuel gas) flows smoothly along the inclined surfaces 281 and 381 and the flat surfaces 283 and 383, respectively. For this reason, the increase in the pressure loss of gas accompanying adding the guide parts 28 and 38 to the gas flow paths 25 and 35 can be suppressed.

  (4) The corrugated plate material is gas-filled so that each concave groove on one surface of the corrugated plate material becomes the gas flow paths 25 and 35 and each concave groove on the other surface becomes the water flow paths 26 and 36. Gas flow path forming plates 22 and 32 having flow paths 25 and 35 and water flow paths 26 and 36 can be obtained.

  (5) A plurality of functional parts including a pair of communication passages 27 and 37 and one guide part 28 and 38 are provided on the gas flow path forming plates 22 and 32 at intervals. Therefore, efficient drainage to the water flow paths 26 and 36 by the functional unit can be performed over a wide range inside the single cell 10.

  (6) The communication holes 29 and 39 were formed in the corners 251 and 351 formed at positions adjacent to the end portions 282 and 382 on the downstream side of the guide portions 28 and 38 in the gas flow paths 25 and 35, respectively. Thereby, the water that flows into the gas flow paths 25 and 35 and reaches the corners 251 and 351 can be moved to the water flow paths 26 and 36 through the communication holes 29 and 39. Therefore, although the corner portions 251 and 351 are formed by providing the guide portions 28 and 38 in the gas flow paths 25 and 35, it is possible to suppress water from staying in the corner portions 251 and 351.

  (7) The gas flow path forming plates 22 and 32 were formed by roll-forming metal plate materials along the width direction W orthogonal to the extending direction L of the gas flow paths 25 and 35, respectively. Further, the guide portions 28 and 38 are formed at positions adjacent to the pair of communication passages 27 and 37 of the inner ridges 23 and 33 in the width direction W, respectively. An apparatus used for roll forming includes a pair of rolls each having a plurality of cutting blades laminated in the axial direction (not shown). According to the present embodiment, the communication paths 27 and 37 can be obtained simply by adding the shape corresponding to the guide portions 28 and 38 to the cutting blades forming the communication paths 27 and 37 among the plurality of cutting edges constituting each roll. It becomes possible to form the gas flow path forming plates 22 and 32 having. Therefore, the gas flow path forming plates 22 and 32 can be manufactured only by changing the shape of a part of the plurality of cutting blades constituting the existing roll.

In addition, the said embodiment can also be changed as follows, for example.
The gas flow path forming plates 22 and 32 may be formed of a metal plate material other than a stainless steel plate such as a titanium plate.

The protruding end surfaces of the guide portions 28 and 38 may be configured by only the inclined surfaces 281 and 381 without the flat surfaces 283 and 383.
-As shown in FIG. 7, the guide parts 28 and 38 can be formed in the step shape from which a protrusion amount becomes large toward the downstream. Even with such a configuration, the gas flow passing through the portions where the guide portions 28 and 38 are disposed in the gas flow paths 25 and 35 includes a directional component from the flat separator 21 side to the membrane electrode assembly 13 side of the gas flow path 25. As a result, the flow rate of the gas is increased.

  A pair of communication passages 27 and 37, such as partially overlapping an arrangement portion of the guide portions 28 and 38 and a range where the upstream communication passages 27 and 37 of the pair of communication passages 27 and 37 open. The guide portions 28 and 38 and the communication passages 27 and 37 may be arranged such that the upstream end portions 273 and 373 are upstream of the downstream end portions 282 and 382 of the guide portions 28 and 38. .

  Further, as shown in FIG. 8, the guide portions are arranged such that the upstream ends 273 and 373 of the pair of communication passages 27 and 37 are downstream of the downstream ends 282 and 382 of the guide portions 28 and 38. 28 and 38 and communication paths 27 and 37 can be arranged. In the example shown in FIG. 8, the upstream end portions 273 and 373 of the pair of communication passages 27 and 37 are more paired with the pair of communication passages 27 and 37 than the downstream end portions 282 and 382 of the guide portions 28 and 38. Among them, the upstream side communication passages 27 and 37 are located on the downstream side by the opening width in the extending direction L. In the example shown in FIG. 8, the directional component from the membrane electrode assembly 13 side to the flat separator 21 side in the velocity vector of the oxidant gas flowing through the gas flow path 25 is within the range indicated by “S” in the figure. While it becomes a positive value, it becomes a negative value in parts other than the range S.

  In short, the upstream side of the pair of communication passages 27 and 37 is within a range in which the directional component from the membrane electrode assembly 13 side toward the flat separator 21 side in the velocity vector of the oxidant gas flowing through the gas flow path 25 has a positive value. The shapes of the communication passages 27 and 37 and the guide portions 28 and 38 may be determined so that the end portions 273 and 373 are arranged. Even with such a configuration, a part of the flow of the oxidant gas after passing through the portion where the guide portions 28 and 38 are disposed is directed to the inside of the communication passages 27 and 37. Water WT collected around the communication path 27 in the gas diffusion layer 17 can be introduced into the communication path 27 by using a gas flow (flow indicated by an arrow F2 in FIG. 5).

  -Instead of forming the guide portions 28 and 38 in a shape in which the bottom walls of the gas flow paths 25 and 35 protrude inward of the gas flow paths 25 and 35, the side walls of the gas flow paths 25 and 35 are provided. May be formed so as to protrude inward of the gas flow paths 25 and 35. Even with such a configuration, the cross-sectional area of the gas flow path 25 becomes narrower toward the downstream side in the arrangement portion of the guide portions 28 and 38 inside the single cell 10. While including a directional component from the bottom side (flat separator 21 side) toward the opening side (membrane electrode assembly 13 side), the flow rate of the oxidizing gas can be increased.

  The guide portions 28 and 38 can be formed in a shape extending in a rectangular cross section in the width direction W, or formed in a shape extending in a cross-sectional arc shape in the width direction W. In short, as long as the inner wall surfaces of the gas flow paths 25 and 35 protrude toward the inside of the gas flow paths 25 and 35 in such a manner that the passage sectional areas of the gas flow paths 25 and 35 are partially narrowed. The guide portions 28 and 38 can be formed in an arbitrary shape.

  -The function part which consists of a pair of communication paths 27 and 37 and one guide part 28 and 38 is not limited to arrange | positioning at equal intervals on the gas flow path formation plates 22 and 32, but it is so many that it is easy to generate | occur | produce water. It may be arranged.

  In each gas flow path forming plate 22, 32, each guide part 28 is arranged so that the guide parts 28 provided in the adjacent gas flow paths 25, 35 are shifted in the extending direction L. It may be. Specifically, each guide unit 28 can be arranged as in [Specific example 1] and [Specific example 2] below.

  As shown in FIG. 9, in the gas flow path forming plate 62 of [Specific Example 1], a functional unit including a pair of communication paths 27 and one guide section 28 adjacent to the communication paths 27 is provided for each gas flow path. 25 and 35 are arranged at equal intervals in the extending direction L. In addition, these functional units are arranged so that the functional unit provided in one of the adjacent gas flow paths 25 and 35 and the functional unit provided in the other are alternate in the extending direction L.

  As shown in FIG. 10, in the gas flow path forming plate 72 of [Specific Example 2], “a pair of communication paths 27” are arranged at equal intervals in the extending direction L with respect to the gas flow paths 25 and 35. At the same time, they are arranged on a straight line extending in the width direction W. Further, in the gas flow path forming plate 72, the guide portions 28 are not provided at positions adjacent to all “a pair of communication paths 27”, but every other pair of “pairs” in the extending direction L and the width direction W. It is provided at a position adjacent to the communication passage 27 ".

Hereinafter, the effect by arrange | positioning the guide part 28 in this way is demonstrated.
The fuel cell according to the above-described embodiment has a structure in which the protruding ends of the inner ridges 23 and 33 are in contact with the gas diffusion layers 17 and 18 (see FIG. 5). A part of the side surface is blocked by the protruding ends of the inner ridges 23 and 33 so that the gas (fuel gas or oxidant gas) does not easily enter the gas diffusion layers 17 and 18. Such a structure may be a cause of hindering improvement in power generation efficiency of the fuel cell.

  By reducing the length in the width direction W of the inner ridges 23 and 33 of the gas flow path forming plates 22 and 32 (see FIG. 2), the inner ridges 23 and 33 on the surfaces of the gas diffusion layers 17 and 18 are reduced. It is possible to narrow the portion blocked by the tip. However, the fuel cell has a structure in which the gas flow path forming plates 22 and 32 are supported at the contact portions between the protruding ends of the inner ridges 23 and 33 and the gas diffusion layers 17 and 18. There is a limit to shortening the length of the inner ridges 23 and 33 in the width direction W.

  Here, in the fuel cell of the modified example employing the gas flow path forming plate shown in FIG. 9 and FIG. 10, the guide part 28 partially reduces the passage cross-sectional area of the gas flow paths 25 and 35 (so-called Therefore, the internal pressure of the portion where the guide portion 28 is disposed in the gas flow paths 25 and 35 and the upstream portion thereof are higher than those of the other portions. And in the fuel cell of this modification, the guide part 28 provided in each of the two gas flow paths 25 and 35 sandwiching the one inner ridge 23 and 33 is arranged at a position shifted in the extending direction L. ing.

  As a result, the guide portion 28 is disposed in one of the portions (indicated by A in FIGS. 9 and 10) of the portions sandwiching the inner ridges 23 and 33 between the adjacent gas flow paths 25 and 35. Thus, the internal pressure can be increased and the internal pressure can be relatively reduced without providing the guide portion 28 on the other side (portion B). In this way, in the fuel cell of the above modification, a pressure difference can be generated between the two gas flow paths 25 and 35 sandwiching the one inner ridge 23 and 33 therebetween.

  Therefore, as indicated by arrows in FIG. 9 and FIG. 10, by using the pressure difference, the gas diffusion layers 17 and 18 are adjacent to each other through the portion where the protruding ends of the inner protrusions 23 and 33 are in contact. Gas can flow from one of the matching gas flow paths 25, 35 to the other. As a result, a large amount of power generation gas can be supplied to the portion of the membrane electrode assembly 13 where the inner ridges 23 and 33 are in contact, so that the power generation efficiency of the fuel cell can be improved. .

  In addition, if each guide part 28 is arrange | positioned so that the guide parts 28 provided in the adjacent gas flow paths 25 and 35 may become the same position in the extending direction L like embodiment mentioned above, it will adjoin gas. Since the guide part 28 is arrange | positioned in both of each part which pinches | interposes the inner side protrusions 23 and 33 in the flow paths 25 and 35, and an internal pressure becomes high, the said pressure difference cannot be generated. In addition, since the internal pressure of the portion where the guide portion 28 is disposed in the gas flow passages 25 and 35 is higher than that of the other portions, the portion sandwiched between the portions (specifically, the gas diffusion layer 17, 18 and the inner projecting ridges 23 and 33 are in contact with the projecting ends), gas and water are likely to stay.

  In this respect, in the fuel cell according to the modified example, by causing the pressure difference, the gas can smoothly flow through the portions of the gas diffusion layers 17 and 18 where the protruding ends of the inner ridges 23 and 33 are in contact. become able to. Thereby, since retention of gas and water can be suppressed, power generation efficiency can be improved.

  Further, the upstream portion where water is hardly generated in each separator has the structure of [specific example 1] (see FIG. 9) and the downstream portion where water is easily generated is [specific example 2] (see FIG. 10). A separator having a structure in which the structure of [Specific Example 1] and the structure of [Specific Example 2] are combined can be employed.

  In addition, each functional part is arranged in the gas flow path forming plate 62 (FIG. 9) so that the functional part provided in one of the adjacent gas flow paths 25 and 35 and the functional part provided in the other are alternate in the extending direction L. The functional units may be arranged so as to be diagonally arranged or arranged in a zigzag manner. In addition, some or all of the functional units may be irregularly arranged.

  Further, the guide portions 28 are not limited to be provided at positions adjacent to every other “pair of communication passages 27” in the gas flow path forming plate 72 (see FIG. 10). It may be provided at a position adjacent to the communication path 27 ", or may be provided at a position adjacent to every other" pair of communication paths 27 ". It is also possible to arrange part or all of the guide part 28 irregularly.

-You may comprise a function part by the 3 or more communicating path arrange | positioned in the position close | similar to each other in the extending direction L, and one guide part 28,38.
-The gas flow path forming plates 22 and 32 are not limited to the corrugated plate, but have a concave cross section in the width direction W, such as a plate having a rectangular wave shape or a sawtooth shape. Any shape can be adopted as long as it has an uneven shape in which convex portions and convex portions are alternately arranged. Further, as the gas flow path forming plates 22 and 32, the gas flow path forming plates 22 and 32 are arranged so that the concave grooves that become the gas flow paths 25 and 35 are twisted positions, or the concave grooves that become the gas flow paths 25 and 35. Adopting a meanderingly extending one, a concave groove forming each water flow channel 26, 36 being arranged in a twisted position, a concave groove forming each water flow channel 26, 36 extending meandering, etc. You can also.

  The inner ridges 23 and 33 are not limited to be formed in a shape extending in a straight line in the extending direction L, and the inner ridges 23 and 33 are arranged at one or a plurality of locations on the upstream side and the downstream side. You may form in the shape extended in the state which the part shifted in the width direction W. In this case, the “pair of communication passages 27” can be formed at portions shifted in the width direction W of the inner ridges 23, 33 so that the inner ridges 23, 33 are aligned in the extending direction.

-Although each guide part 28 and 38 was formed in the same shape, the shape of these guide parts 28 and 38 can be formed in a different shape according to the arrangement position in the gas flow path formation plates 22 and 32. FIG.
The gas flow path forming plate 22 having the guide portion 28 is provided on the cathode side of the membrane electrode assembly 13 and the gas flow path forming plate having no guide portion 38 is provided on the anode side of the membrane electrode assembly 13. It may be. In this case, an anode side gas flow path forming plate that does not have the communication path 37 is adopted, or a gas flow path is formed on the anode side of the membrane electrode assembly 13 and the anode is formed. The gas flow path forming plate on the side can be omitted. In addition, a gas flow path forming plate not having the guide portion 28 is provided on the cathode side of the membrane electrode assembly 13, and a gas flow path forming plate 32 having the guide portion 38 is provided on the anode side of the membrane electrode assembly 13. You may do it.

  -Instead of the flat separators 21 and 31, a separator having an arbitrary shape such as a separator having irregularities (dimples or protrusions) or a corrugated separator can be adopted.

  DESCRIPTION OF SYMBOLS 10 ... Single cell, 11 ... 1st frame, 12 ... 2nd frame, 13 ... Membrane electrode assembly, 14 ... Solid polymer electrolyte membrane, 15, 16 ... Electrode catalyst layer, 17, 18 ... Gas diffusion layer, 20 ... 1st separator, 30 ... 2nd separator, 21, 31 ... Flat separator, 22, 32, 62, 72 ... Gas flow path forming plate, 23, 33 ... Inner ridge, 24, 34 ... Outer ridge, 25, 35 ... gas flow path, 251, 351 ... corner, 26, 36 ... water flow path, 27, 37 ... communication path, 271, 371 ... rib, 273, 373 ... end, 28, 38 ... guide, 281, 381 ... Inclined surface, 282, 382 ... end, 283, 383 ... flat surface, 29, 39 ... communication hole, 41 ... supply passage, 42 ... discharge passage, 51 ... supply passage, 52 ... discharge passage.

Claims (6)

A gas flow path forming plate of a single cell of a fuel cell interposed between a membrane electrode assembly and a plate-shaped separator,
A plurality of groove-shaped gas flow channels arranged so as to be arranged at intervals on a surface facing the membrane electrode assembly;
A concave water channel formed on the back surface of the protrusion located between the adjacent gas channels;
A plurality of communication passages that are respectively formed at positions spaced in the direction in which the protrusions extend in the protrusions, and that communicate the gas flow path and the water flow path;
The gas passage has a shape in which an inner wall surface of the gas passage projects inward in a manner in which a passage cross-sectional area of the gas passage is partially narrowed, and the gas in the plurality of communication passages An end portion on the upstream side in the flow direction of the gas flowing in the flow path has a shape that is arranged in a range in which the direction component from the membrane electrode assembly side to the separator side in the gas velocity vector becomes a positive value. And a gas channel forming plate for a fuel cell. The fuel cell gas flow path forming plate according to claim 1,
The fuel cell gas flow path is characterized in that the downstream end of the guide portion in the flow direction and the upstream end of the plurality of communication passages in the flow direction are the same. Forming board. The gas flow path forming plate for a fuel cell according to claim 1 or 2,
The gas channel forming plate for a fuel cell, wherein the guide portion has an inclined surface inclined in a shape in which a protruding amount of the inner wall surface increases toward a downstream side in the flow direction. The fuel cell gas flow path forming plate according to any one of claims 1 to 3,
The gas flow path forming plate for a fuel cell, characterized in that the gas flow path forming plate is a plate material having a concavo-convex shape in a direction orthogonal to a direction in which the gas flow path extends. In the fuel cell gas flow path forming plate according to any one of claims 1 to 4,
The plurality of communication passages and one guide portion constitute one functional portion that functions independently, and a plurality of the functional portions are provided at intervals. Forming board. A fuel cell stack in which a plurality of single cells are stacked,
The fuel cell gas flow according to any one of claims 1 to 5, wherein the single cell is interposed between a membrane electrode assembly, a plate-shaped separator, and the membrane electrode assembly and the separator. A fuel cell stack comprising a path forming plate.

Images