JP2005243651A - Fuel cell and current collector thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell and a current collector thereof, improving the distribution of reactive gas to each gas path for a fuel cell. <P>SOLUTION: In a collector panel 10 for the fuel cell, a gas path 50, in which a reactive gas flows to an accumulative layer face accumulated on an electrolyte membrane, is formed. A supplying hole 61 to distribute and supply the reactive gas into the path 50 and an exhaust hole 62 for exhausting the reactive gas in the path 50 are formed. In the state where each collector panel 10 is accumulated in a plural forms with an intervening electrolyte membrane, a supply manifold is formed through gathering of the supply hole 61 and an exhaust manifold is formed through gathering of the exhaust hole 62. An opening area for the exhaust hole 62 is designed to be larger than that for the opening area for the supply hole 61 and also a path cross-sectional area on a downstream side of a folded part 50B is designed to be smaller than that of a path cross-sectional area on an upstream side of the folded part 50 B. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention includes a laminate in which a plurality of electrolyte membranes and collector plates provided with reaction electrodes are laminated, and each gas passage formed between the electrolyte membrane and the collector plates in the laminate. A fuel cell in which a supply manifold for distributing and supplying the reaction gas and a discharge manifold for discharging the reaction gas in the same gas passage are formed, and the gas passage, and a supply hole and a discharge hole for forming each manifold are formed. The present invention relates to a current collector plate for a fuel cell.

  A fuel cell includes a stack having a stack structure in which a plurality of single cells (cells) are stacked. This cell consists of an electrolyte membrane provided with reaction electrodes on both sides and a current collector plate laminated on both sides of the electrolyte membrane. The surface of the current collector plate laminated on the electrolyte membrane has fuel gas and oxidation A gas passage for flowing a reaction gas such as an agent gas is formed. Further, a supply manifold and a discharge manifold extending in the stacking direction are provided inside the stacked body, and the reaction gas is supplied and discharged between each manifold and the gas passage of the current collector plate. . Each of these manifolds is configured as a passage in which a plurality of holes formed at corresponding positions of the respective current collecting plates are gathered in series, as described in Patent Document 1, for example.

In such a fuel cell, the reaction gas supplied from the inlet of the supply manifold to the inside thereof is first distributed and supplied to the gas passages of the respective cells through supply manifold forming supply holes formed in the current collector plate. The reaction gas distributed and supplied to each gas passage flows through the gas passage and is then discharged to the discharge manifold through a discharge manifold forming discharge hole formed in the current collector plate. Then, the reaction gas is caused to flow through the gas passage of each cell in this manner, so that an electromotive force is generated at the reaction electrode by an electrochemical reaction.
Japanese Patent Laid-Open No. 10-106594

  Thus, in the fuel cell, the electromotive force is taken out by flowing the reaction gas through the gas passage of each current collector plate. Therefore, in order to obtain a desired power generation efficiency in the fuel cell, it is desirable to appropriately control the flow rate and distribution of the reaction gas in such a gas passage.

  However, as described above, in the fuel cell in which the reaction gas is supplied and discharged between the gas passages and the manifolds common to them, the flow rate of the reaction gas in each gas passage and the distribution thereof. The following problems cannot be ignored.

  That is, the flow rate of the reaction gas tends to decrease as the cell is located farther from the inlet of the supply manifold. For this reason, a sufficient amount of reaction gas is supplied to the cell close to the inlet of the supply manifold, but the reaction gas in the gas passage is not supplied to the cell far from the inlet of the supply manifold. The flow rate becomes insufficient, and the electromotive force decreases. As described above, in the conventional fuel cell, since the reaction gas is unevenly distributed to each gas passage, there is a cell that cannot generate a desired electromotive force, and the power generation efficiency is reduced. It was inevitable.

  The present invention has been made in view of such conventional circumstances, and an object of the present invention is to provide a fuel cell and a current collector plate thereof that can improve the distribution of reaction gas to each gas passage of the fuel cell. .

  In order to achieve the above object, according to the first aspect of the present invention, a gas passage through which a reaction gas flows is formed on a laminated surface laminated on an electrolyte membrane provided with electrodes, and a reaction gas is introduced into the gas passage. In a collector plate of a fuel cell in which a supply manifold forming supply hole for distributing supply and a discharge manifold forming discharge hole for discharging reaction gas in the gas passage are formed, respectively, the gas passage is collected The current plate has a shape that is folded at the end of the electric plate, and the opening area SA1 of the discharge hole in the current collector plate is set larger than the opening area SA2 of the supply hole in the current collector plate, and is downstream of the folded portion. The passage sectional area SA3 is set to be smaller than the passage sectional area SA4 on the upstream side of the folded portion.

  In the fuel cell, the reaction gas supplied to the gas passage from the supply hole for forming the supply manifold is discharged from the gas passage to the discharge manifold through the discharge hole for forming the discharge manifold. It acts and the flow of the reaction gas is regulated. Here, with respect to the gas passage of the current collector plate located near the inlet of the supply manifold, since the reaction gas is supplied from the supply manifold to the gas passage with a relatively high pressure, the flow is regulated, The reaction gas is discharged from the discharge hole relatively quickly.

  On the other hand, in the gas passage of the current collector plate at a position away from the inlet of the supply manifold, the pressure of the reaction gas supplied from the supply manifold is relatively lowered, so that it is greatly affected by the squeezing action of the discharge hole. The reaction gas is difficult to be discharged from the discharge hole. As a result, in the current collector plate located away from the inlet of the supply manifold, the amount of reaction gas supplied to the gas passage through the supply hole is relatively smaller than that of the current collector plate located near the inlet. It begins to decline.

  In this regard, in the above-described configuration of the invention described in claim 1, the opening area SA1 of the discharge hole is set larger than the opening area SA2 of the supply hole with respect to the supply hole and the discharge hole respectively formed in the current collector plate. Therefore, the restriction of the flow due to the restricting action of the discharge hole is weakened, and the reaction gas can be quickly discharged from the gas passage through the discharge hole. Therefore, even when the current collector plate is disposed at a position away from the inlet of the supply manifold, a predetermined amount or more of the reaction gas can flow through the gas passage of the current collector plate, and the reaction gas for each gas passage can be supplied. The distribution bias can be reduced to improve the distribution.

  Furthermore, since the gas passage has a shape that is folded at the end of the current collector plate, the flow rate of the reaction gas in the entire gas passage can be increased, and the gas utilization rate can be increased to improve the power generation efficiency. Will be able to.

  Here, the gas concentration of the reaction gas gradually decreases in the process of flowing through the gas passage, for example, the oxygen concentration for oxidant gas and the hydrogen concentration for fuel gas. For this reason, power generation efficiency tends to be lower on the downstream side of the gas passage than on the upstream side.

  For this reason, in the above configuration, the gas flow velocity in the downstream portion is partially increased by setting the passage cross-sectional area downstream of the folded portion of the gas passage to be smaller than the passage cross-sectional area upstream of the folded portion. I am doing so.

  Then, by causing the reaction gas to flow faster in this way, a decrease in gas concentration can be suppressed in the downstream portion of the gas passage. As a result, the utilization rate of the reaction gas can be increased, and the power generation efficiency in the downstream portion can be improved.

In addition, according to the above-described configuration, it is possible to improve the drainage performance in the downstream portion of the gas passage where moisture tends to stay by increasing the gas flow rate.
According to a second aspect of the present invention, in the current collector plate of the fuel cell according to the first aspect, the current collector plate has a rectangular shape, and the supply hole and the discharge hole are formed at one end of the current collector plate. In addition, a cooling water hole through which cooling water passes is formed between the supply hole and the discharge hole at one end thereof.

  According to a third aspect of the present invention, in the current collector plate of the fuel cell according to the second aspect, the cooling water hole in the supply hole is formed on an extension of the side surface on the end portion side of the current collector plate in the upstream passage. The inner surface of the cooling water hole opposite to the supply hole is formed on the extension of the side surface opposite to the end of the current collector plate in the upstream passage. It is said that.

  According to a fourth aspect of the present invention, in the current collector plate of the fuel cell according to the third aspect, the supply hole and the discharge hole are formed in a rectangular cross section, and the supply hole and the discharge hole are formed. The lengths of the sides of the supply hole and the discharge hole that are perpendicular to the side of the one end portion of the current collector plate are equal to each other.

  Further, according to the experiment by the present inventor, when the opening area SA1 of the discharge hole is set larger than the opening area SA2 of the supply hole as described above, the ratio of these opening areas SA1 and SA2 (SA1 / SA2) It has been confirmed that a better distribution is ensured by setting the value in a range of 1.0 <(SA1 / SA2) <3.0.

  Therefore, in the invention according to claim 5, in the current collector plate of the fuel cell according to any one of claims 1 to 4, the ratio (SA1 / SA2) of the opening areas SA1 and SA2 of the discharge hole and the supply hole. SA2) is set in a range of 1.0 <(SA1 / SA2) <3.0.

  According to a sixth aspect of the present invention, in the current collector plate of the fuel cell according to any one of the first to fifth aspects, a portion in the vicinity of the discharge hole is formed as a lattice-shaped passage, and other portions are formed. At least a part is formed as a plurality of independent passages.

  According to the above configuration, the gas passage is shaped to be folded at the end of the current collector plate, and at least a part of the gas passage other than the vicinity of the discharge hole is formed as a plurality of independent passages. The flow rate of the reactive gas in the gas passage can be increased, and the gas utilization rate can be increased to improve the power generation efficiency.

  However, since the total length of the gas passage is expanded by making the gas passage folded in this way, the reaction gas containing a large amount of water produced by the reduction reaction flows on the downstream side of the gas passage. Therefore, there is a concern that the gas passage is clogged by the liquefaction of the generated water.

  In this regard, in the above-described configuration, the portion near the discharge hole in the gas passage, that is, the downstream portion thereof is a lattice-like passage, so that the diffusion of the reaction gas can be promoted and the drainage can be improved. Accordingly, it is possible to suppress a decrease in power generation efficiency due to the blockage of the gas passage due to moisture. Moreover, since the opening area of the discharge hole is set to be relatively large, the water in the gas passage can be quickly discharged from the discharge hole, and the drainage can be further improved.

  By the way, as described above, the power generation efficiency in the downstream portion can be improved by setting the passage sectional area of the downstream portion of the gas passage smaller than the passage sectional area of the upstream portion. However, on the other hand, if the passage cross-sectional area of the downstream portion is gradually reduced, the flow resistance at the downstream portion gradually increases, and as a result, the pressure loss increases as a whole gas passage. Will come to do. Furthermore, if the passage cross-sectional area of the upstream portion is increased by the amount corresponding to the reduction of the passage cross-sectional area of the downstream portion, the gas flow velocity decreases in the upstream portion, and the power generation efficiency decreases due to the reduction. Will occur.

  Therefore, when setting the passage cross-sectional area of the downstream portion of the gas passage to be smaller than the passage cross-sectional area of the upstream portion, the pressure loss increases due to the reduction of the passage cross-sectional area of the downstream portion and the power generation in the upstream portion It can be said that it is desirable to consider the decrease in efficiency.

  According to the inventors' experiments based on these points, the ratio (SA3 / SA4) of the downstream passage sectional area SA3 and the upstream passage sectional area SA4 of the gas passage is 0.3 <(SA3 / SA4) <1. It is confirmed that by setting the range to 0.0, the decrease in power generation efficiency in the upstream portion of the gas passage and the increase in power generation efficiency in the downstream portion can be suitably balanced while suppressing an increase in pressure loss as much as possible. Has been.

  Therefore, according to the seventh aspect of the present invention, in the current collector plate of the fuel cell according to any one of the first to sixth aspects, the downstream-side passage sectional area SA3 and the upstream-side passage sectional area SA4 of the gas passage The ratio (SA3 / SA4) is set in a range of 0.3 <(SA3 / SA4) <1.0.

  According to an eighth aspect of the present invention, in the current collector plate of the fuel cell according to any one of the first to seventh aspects, a fuel gas passage is provided on one of the laminated surfaces on both sides of the electrolyte layer, and on the other side. The oxidant gas passages are respectively formed as the gas passages, and the fuel gas supply holes and the oxidant gas supply holes as the supply holes and the fuel gas discharge holes and the oxidant gas discharge holes as the discharge holes are respectively formed. The cooling water supply hole and the cooling water discharge hole for discharging the cooling water are respectively formed, and the fuel gas passage and the oxidant gas passage have a symmetrical shape around the bisector of the current collector plate. And the fuel gas supply hole and the oxidant gas supply hole, the fuel gas discharge hole and the oxidant gas discharge hole, and the cooling water supply hole and the cooling water discharge hole are respectively connected to the bisector. It is set to be made is formed on the referred position.

  According to the above configuration, when stacking the current collector plate on the electrolyte membrane, it is not necessary to distinguish between the surface on which the fuel gas passage is formed and the surface on which the oxidant gas passage is formed on the current collector plate. The workability can be improved.

  The invention according to claim 9 includes a laminate in which a plurality of electrolyte membranes and collector plates provided with reaction electrodes are laminated, and the electrolyte membrane and the collector plates are disposed inside the laminate. In the fuel cell in which the supply manifold that distributes and supplies the reaction gas to each formed gas passage and the discharge manifold that discharges the reaction gas in the gas passage are formed along the stacking direction of the stacked body, the gas passage includes: The current collector plate on which the electrolyte membrane is laminated is formed to have a shape that is folded at the end of the current collector plate, and the passage cross-sectional area SB1 of the discharge manifold is the passage cross-sectional area SB2 of the supply manifold. The passage sectional area SB3 on the downstream side of the folded portion is set smaller than the passage sectional area SB4 on the upstream side of the folded portion.

  According to the above configuration, similarly to the first aspect of the invention, it is possible to reduce the uneven distribution of the reaction gas with respect to the gas passage of each cell of the fuel cell and improve the distribution.

  Furthermore, by making the gas passage into a folded shape, the gas flow rate in the entire passage can be increased, the gas utilization rate can be increased, and the power generation efficiency can be improved. In particular, since the gas flow rate is further increased in the downstream portion of the gas passage, it is possible to suppress a decrease in gas concentration and to ensure good drainage and to further improve power generation efficiency. become.

  According to a tenth aspect of the present invention, in the fuel cell according to the ninth aspect, the current collector plate has a rectangular shape, and the supply manifold and the discharge manifold are formed at one end portion of the current collector plate, and one end thereof. In this section, a cooling water manifold through which cooling water passes is formed between the supply manifold and the discharge manifold.

  According to an eleventh aspect of the present invention, in the fuel cell according to the tenth aspect, on the extension of the side surface on the end portion side of the current collecting plate in the upstream passage, the supply manifold has a side opposite to the cooling water manifold. An inner surface is formed, and an inner surface of the cooling water manifold opposite to the supply manifold is formed on an extension of the side surface opposite to the end of the current collector plate in the upstream side passage. .

  According to a twelfth aspect of the present invention, in the fuel cell according to the eleventh aspect, the supply manifold and the discharge manifold are formed in a rectangular cross section, and the current collector is formed with the supply manifold and the discharge manifold. The lengths of the sides of the supply manifold and the discharge manifold that are perpendicular to the side of the one end side of the plate are made equal to each other.

  In a thirteenth aspect of the invention, in the fuel cell according to any of the ninth to twelfth aspects, the ratio (SB1 / SB2) of the passage cross-sectional areas SB1 and SB2 of the manifolds is 1.0 <(SB1 / SB2) <3.0.

According to the above configuration, as in the fifth aspect of the invention, it is possible to ensure better distribution to each cell.
According to a fourteenth aspect of the present invention, in the fuel cell according to any one of the ninth to thirteenth aspects, the vicinity of the communicating portion with the exhaust manifold is formed as a lattice-shaped passage, and at least the other portions. A part is supposed to be formed as a plurality of independent passages.

  According to the above configuration, as in the sixth aspect of the invention, the power generation efficiency can be improved by increasing the flow rate of the reaction gas in the gas passage. Furthermore, in the downstream portion of the gas passage, the drainage can be improved and the decrease in power generation efficiency due to the blockage of the gas passage due to moisture can be suppressed.

  According to a fifteenth aspect of the present invention, in the fuel cell according to the fourteenth aspect of the present invention, the stacked body is formed by stacking a plurality of the electrolyte membranes and the current collector plates in a direction perpendicular to the direction of gravity.

  According to the above configuration, in the vicinity of the communicating portion with the discharge manifold in the gas passage, moisture can move downward in the gravitational direction through the passage formed in a lattice shape. Therefore, in this lattice-like gas passage, the reaction gas flow path can be reliably secured at least in the upper part in the direction of gravity, and the reduction in power generation efficiency due to the blockage of the gas passage due to moisture is effective. Can be suppressed.

  According to a sixteenth aspect of the present invention, in the fuel cell according to any one of the ninth to fifteenth aspects, the ratio of the downstream passage sectional area SA3 and the upstream passage sectional area SB4 of the gas passage (SB3 / SB4). Is set in a range of 0.3 <(SB3 / SB4) <1.0.

  According to the said structure, the effect of the invention in any one of Claim 9 thru | or 15 can be show | played more suitably.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 shows a planar structure of a current collector plate 10 used in a polymer electrolyte fuel cell 30 according to the present embodiment, and FIG. 2 shows an exploded structure of one cell 31 in the fuel cell 30. FIG. 3 shows a perspective structure of the fuel cell 30.

  As shown in each of these drawings, the fuel cell 30 includes a laminate 32 in which a plurality of substrates 20 and current collectors 10 are alternately laminated, and a pair of side plates 12 sandwiching the laminate 32 from both sides. It is configured. In the state where the fuel cell 30 is used, the stacking direction of the stacked body 32 is set to be perpendicular to the direction of gravity (the vertical direction in each figure).

  The substrate 20 includes an electrolyte membrane 22 and a reaction electrode (a cathode and an anode, only one of which is shown in FIG. 2) 24 sandwiching the electrolyte membrane 22 from both sides. The electrolyte membrane 22 is formed of a polymer material such as a fluorine resin that exhibits ionic conductivity in a moderately wet state. Each reaction electrode 24 is formed of a carbon fiber containing a catalyst such as platinum.

  Further, as shown in FIG. 1, the current collector plate 10 is formed in a rectangular plate shape by a conductive material such as carbon. In addition to the function of electrically connecting the reaction electrodes 24 located on both sides of the current collector plate 10, the current collector plate 10 supplies a reaction gas such as a fuel gas or an oxidant gas to the surface of each reaction electrode 24. It also has a function of forming a gas passage for the purpose. As shown in FIG. 2, a single battery (cell) 31 is constituted by one substrate 20 and each current collector plate 10 laminated on both sides of the substrate 20. In general, they have a structure connected in series.

Further, a gas passage (oxidant gas passage) 50 for flowing an oxidant gas containing oxygen such as air is formed in one of the stacked surfaces of the current collector plate 10 facing the reaction electrode 24.
As shown in FIG. 1, the gas passage 50 extends from one end side (right end side in the figure) to the other end side (left end side in the figure) of the current collector plate 10. It has a substantially U-shape that is folded back and returns to the one end side of the current collector plate 10 again, and is surrounded by the broken lines in the drawing, that is, by the upstream portion 50A, the folded portion 50B, and the downstream portion 50C. It is configured.

  Further, a supply hole 61 for supplying the oxidant gas passage 50 to the oxidant gas passage 50 and a discharge hole 62 for discharging the oxidant gas from the gas passage 50 are formed at one end of the current collector plate 10, respectively. Has been. In a state where the fuel cell 30 is used, of these holes 61 and 62, the supply hole 61 is located on the upper side in the gravity direction, and the discharge hole 62 is located on the lower side in the same direction.

  Of the portions 50A to 50C, the upstream portion 50A is connected to the supply hole 61, and the downstream portion 50C is connected to the discharge hole 62. Accordingly, the reaction gas (oxidant gas) supplied from the supply hole 61 to the gas passage 50 flows in order from the upstream portion 50A, the turn-back portion 50B, and the downstream portion 50C, and then from the gas passage 50 through the discharge hole 62. Discharged.

  In the gas passage 50, the upstream portion 50 </ b> A is configured as a plurality of independent passages by a plurality of parallel grooves 51. On the other hand, the folded portion 50B is configured as a lattice-shaped passage by the plurality of lattice grooves 52. In addition, the downstream portion 50C is configured as a plurality of independent passages by a plurality of parallel grooves 53 in the vicinity of the folded portion 50B, and the portion located at the most downstream side, that is, the vicinity of the discharge holes 62 is a plurality of lattices. The grooves 54 are configured as lattice-shaped passages.

  In the present embodiment, since the shape of the gas passage 50 is the shape having the folded portion 50B as described above, the total passage length is expanded as compared with the case where the passage 50 is formed in a linear shape. Become. As a result, the average flow rate of the reaction gas in the entire passage is increased, the gas utilization rate is increased, and the power generation efficiency is improved. In addition, since the portion in the vicinity of the discharge hole 62 in the downstream portion 50C is configured as a lattice-like passage, the diffusion of the reaction gas is promoted and the drainage is improved.

  Furthermore, the total passage sectional area SG1 of each independent passage located in the vicinity of the folded portion 50B in the downstream portion 50C is set smaller than the total passage sectional area SG2 of each independent passage in the upstream portion 50A.

  Thus, by setting each total passage cross-sectional area SG1, SG2, the gas flow velocity in the downstream portion 50C is further partially increased. For this reason, in the downstream portion 50C where the concentration of the reaction gas is concerned, the decrease in the gas concentration is suppressed as much as possible, and the utilization rate of the reaction gas is increased. In particular, when air is used as the oxidant gas, since the gas concentration (oxygen concentration) is low from the beginning, such an improvement in the gas utilization rate is particularly remarkable on the oxidant gas passage 50 side. Furthermore, the increase in gas flow rate also improves the drainage performance in the downstream portion 50C where water tends to stay.

  However, if the total passage cross-sectional area SG1 of the downstream portion 50C is gradually set to be small here, the flow path resistance in the downstream portion 50C gradually increases. It will increase. Furthermore, in order to secure the passage sectional area of the entire gas passage, it is desirable to relatively enlarge the total passage sectional area SG2 of the upstream portion 50A by an amount corresponding to the reduction of the total passage sectional area SG1 of the downstream portion 50C. In this way, when the total passage sectional area SG2 of the upstream portion 50A is enlarged, the gas flow velocity is decreased in the upstream portion 50A, and the power generation efficiency is reduced.

According to the experiment by the present inventor, the ratio (SG1 / SG2) of each of the total passage sectional areas SG1 and SG2 is 0.3 <(SG1 / SG2) <1.0 (Expression 1)
It is confirmed that the reduction in power generation efficiency in the upstream portion 50A of the gas passage 50 and the increase in power generation efficiency in the downstream portion 50C can be suitably balanced while suppressing an increase in pressure loss as much as possible. Has been. For this reason, in this embodiment, this area ratio (SG1 / SG2) is set to “0.7” within the above range.

  In addition, a gas passage (fuel gas passage) for flowing a fuel gas containing hydrogen is formed on a laminated surface (not shown) opposite to the laminated surface where the oxidant gas passage 50 is formed in the current collector plate 10. ing. A supply hole 71 for supplying the fuel gas to the fuel gas passage and a discharge hole 72 for discharging the fuel gas from the gas passage are formed at the other end of the current collector plate 10. In a state where the fuel cell 30 is used, of these holes 71 and 72, the supply hole 71 is located on the upper side in the gravity direction, and the discharge hole 72 is located on the lower side in the same direction.

  In the present embodiment, the fuel gas passage is formed to have the same shape symmetrical to the oxidant gas passage 50 around the center line C that bisects the current collector plate 10. Further, the supply hole 71 and the discharge hole 72 of the fuel gas passage are also provided at positions that are line-symmetric with the supply hole 61 and the discharge hole 62 of the oxidant gas passage 50 with respect to the center line C, respectively. For this reason, when stacking the current collector plate 10 on the substrate 20, it is not necessary to distinguish between the stacked surface where the fuel gas passage is formed and the stacked surface where the oxidant gas passage 50 is formed in the current collector plate 10. Become.

  Further, at one end of the current collector plate 10, a cooling water passage (not shown) formed inside a part of the current collector plate 10 is cooled between the supply hole 61 and the discharge hole 62 of the oxidant gas passage 50. A supply hole 81 for supplying water is formed. On the other hand, a discharge hole 82 for discharging cooling water from the cooling water passage is formed between the supply hole 71 and the discharge hole 72 of the fuel gas passage at the other end of the current collector plate 10.

  As shown in FIG. 3, a seal member 90 made of an insulating material is provided between the current collector plates 10 so as to fill the gaps between the current collector plates 10 formed on the outer periphery of the substrate 20. . In the seal member 90, holes (not shown) having the same shape are formed at positions corresponding to the holes 61, 62, 71, 72, 81, 82 formed in the current collector plate 10, respectively. In the stacked body 32, a plurality of manifolds 60A, 60B, 70A, 70B, 80A, and 80B extending along the stacking direction are formed by collecting the holes of the current collector plate 10 and the seal member 90. Has been.

  That is, a supply manifold 60A for distributing and supplying the oxidant gas to the oxidant gas passage 50 and a discharge manifold 60B for discharging the oxidant gas from the gas passage 50 are formed in the laminate 32, respectively. ing. Similarly, a supply manifold 70A for distributing and supplying the fuel gas to the fuel gas passage and an exhaust manifold 70B for discharging the fuel gas from the gas passage are formed in the stacked body 32, respectively.

  As described above, since the discharge holes 62 and 72 are located below the supply holes 61 and 71 in the gravity direction, the discharge manifolds 60B, 60B, 70A, 70B among the manifolds 60A, 60B, 70A, 70B. 70B will be arranged below the supply manifolds 60A, 70A in the direction of gravity. For this reason, the moisture contained in the reaction gas in the oxidant gas passage 50 and the fuel gas passage quickly moves to the downstream side by the action of gravity in addition to the supply pressure of the reaction gas, and is discharged from the discharge holes 62 and 72. Will come to be.

  Similarly, a supply manifold 80A for supplying cooling water to the cooling water passage and a discharge manifold 80B for discharging the cooling water from the cooling water passage are formed in the laminated body 32, respectively.

  The end portions of these manifolds 60A, 60B, 70A, 70B, 80A, 80B are closed by one side plate 12. The other side plate 12 is formed with inlets 126a, 127a, and 128a for supplying reaction gas or cooling water to the supply manifolds 60A, 70A, and 80A, and from the discharge manifolds 60B, 70B, and 80B. Outlets 126b, 127b, and 128b for discharging the reaction gas or the cooling water are formed.

  In the fuel cell 30 according to the present embodiment, the cross-sectional areas of the manifolds 60A and 60B for the oxidant gas and the manifolds 70A and 70B for the fuel gas are set so as to have the following relationships, respectively.

  That is, for each of the manifolds 60A and 60B for the oxidant gas, the passage sectional area SO1 of the discharge manifold 60B is set larger than the passage sectional area SO2 of the supply manifold 60A. Similarly, the passage cross-sectional area SH1 of the discharge manifold 70B is set larger than the passage cross-sectional area SH2 of the supply manifold 70A in the manifolds 70A and 70B for fuel gas.

  Further, in order to satisfy such a relationship, the same relationship applies to the opening areas of the supply holes 61 and 71 and the discharge holes 62 and 72 that substantially determine the passage sectional areas SO1, SO2, SH1, and SH2. Is set. That is, the opening area of the discharge hole 62 for the oxidant gas passage 50 is set larger than the opening area of the supply hole 61, and the opening area of the discharge hole 72 for the fuel gas passage is larger than the opening area of the supply hole 71. Is set.

  Then, the passage cross-sectional areas of the manifolds 60A, 60B, 70, 70B and the opening areas of the supply holes 61, 71 and the discharge holes 62, 72 are set in this way, so that the discharge holes 62, 72 and these The restriction of the gas flow due to the constriction action of the exhaust manifolds 60B and 70B formed together is weakened, and the reaction gas is quickly discharged from the gas passages 50 to the discharge holes 62 and 72.

  FIG. 4 is a graph showing the flow rate of the reaction gas (oxidant gas) in each oxidant gas passage 50. The solid line indicates the flow rate of the reaction gas in this embodiment, and the two-dot chain line indicates the supply manifold 60A and the discharge manifold 60B. The flow rates of the reaction gases in the comparative examples in which the passage cross-sectional areas (opening areas of the supply holes 61 and the discharge holes 62) are set to be equal are shown.

  As indicated by the two-dot chain line in the figure, in the above comparative example, the flow rate of the reaction gas in the gas passage 50 located far from the inlet 126a of the supply manifold 60A is greatly reduced, and the reaction gas is reduced to each gas. It can be seen that the distribution is biased toward the passage 50. For this reason, a predetermined electromotive force cannot be generated in the cell 31 located away from the inlet 126a, and a decrease in the power generation efficiency of the entire fuel cell cannot be avoided.

  On the other hand, in the present embodiment, as shown by the solid line in the figure, a predetermined amount or more of the reactive gas flows in the gas passage 50 located away from the inlet 126a of the supply manifold 60A. The distribution deviation of the reaction gas with respect to the gas passage 50 is reduced. This tendency is the same for the fuel gas passage because the fuel gas passage has the same shape as the oxidant gas passage 50, and the distribution of the reaction gas (fuel gas) in the fuel gas passage is uneven. Will also decrease.

According to the inventors' experiment, the ratio (SO1 / SO2) of the passage sectional area SO1 of the exhaust manifold 60B of the oxidant gas passage 50 to the passage sectional area SO2 of the supply manifold 60A is 1.0 <(SO1 / SO2). <3.0 (Formula 2-1)
More preferably,
1.3 <(SO1 / SO2) <2.0 (Formula 2-2)
And the ratio (SH1 / SH2) of the passage sectional area SH1 of the discharge manifold 70B of the fuel gas passage to the passage sectional area SH2 of the supply manifold 70A is 1.0 <(SH1 / SH2) <3.0. ... (Formula 3-1)
More preferably,
1.3 <(SH1 / SH2) <2.0 (Formula 3-2)
By setting to this range, it has been confirmed that better distribution is ensured in each of the oxidant gas passages 50 and the fuel gas passages. For this reason, in this embodiment, the ratio (SO1 / SO2, SH1 / SH2) of each of the passage cross-sectional areas is set to “1.5” which is a value in the above range.

As described above, according to the fuel cell 30 and the current collector plate 10 according to the present embodiment, the following operational effects can be achieved.
(1) Passage cross-sectional areas of the discharge manifolds 60B and 70B (opening areas of the discharge holes 62 and 72) SO1 and SH1 are taken as passage cross-sectional areas of the supply manifolds 60A and 70A (opening areas of the supply holes 61 and 71) SO2. , SH2 can be set to be larger than a predetermined amount of gas in the gas passages located away from the inlets 126a, 127a of the supply manifolds 60A, 70A, and the reaction gas can be distributed to the gas passages. It is possible to improve the distribution by reducing the bias.

  (2) In particular, the passage cross-sectional area of each discharge manifold 60B, 70B (open area of each discharge hole 62, 72) SO1, SH1 and the cross-sectional area of each supply manifold 60A, 70A (open area of each supply hole 61, 71) ) The area ratio (SO1 / SO2, SH1 / SH2) to SO2 and SH2 is in the range of 1.0 <(SO1 / SO2) <3.0 and 1.0 <(SH1 / SH2) <3.0, respectively. By setting, the effect (1) can be made more remarkable.

  (3) The oxidant gas passage 50 and the fuel gas passage are shaped so as to be folded back at the end of the current collector plate 10, and their upstream portions 50A are formed as a plurality of independent passages. It is possible to increase the flow rate of the reaction gas at, and to improve the power generation efficiency by increasing the gas utilization rate. In addition, since the portions near the discharge holes 62 and 72 in each gas passage are grid-like passages, drainage can be improved. And since the opening area of the discharge holes 62 and 72 is set relatively large, the water | moisture content in a gas channel can be discharged | emitted from the discharge holes 62 and 72 rapidly, and further drainage property is aimed at. Will be able to.

  (4) The oxidant gas passage 50 and the fuel gas passage are folded back at the end of the current collector plate 10, and the total passage sectional area SG1 of each independent passage of the downstream portion 50C located downstream of the folded portion 50B. Is set to be smaller than the total passage cross-sectional area SG2 of each independent passage of the upstream portion 50A, the gas flow rate in the downstream portion 50C can be partially increased to suppress a decrease in gas concentration. The power generation efficiency in the portion 50C can be improved. In addition, the increase in the gas flow rate can improve the drainage performance in the downstream portion 50C where moisture tends to stay.

  (5) In particular, the ratio (SG1 / SG2) of the total passage cross-sectional areas SG1 and SG2 of the downstream portion 50C and the upstream portion 50A is set in a range of 0.3 <(SG1 / SG2) <1.0. Accordingly, it is possible to suitably balance the decrease in power generation efficiency in the upstream portion 50A of each gas passage and the increase in power generation efficiency in the downstream portion 50C while suppressing an increase in pressure loss as much as possible.

  (6) The oxidant gas passage 50 and the fuel gas passage are formed to have the same symmetrical shape around the center line C that bisects the current collector plate 10, and the supply hole 61 of the oxidant gas passage 50 is formed. Further, the discharge hole 62 and the supply hole 71 and the discharge hole 72 of the fuel gas passage are provided at positions that are line-symmetric with respect to the center line C, respectively. Therefore, when stacking the current collector plate 10 on the substrate 20, there is no need to discriminate between the stack surface on which the oxidant gas passage 50 is formed and the stack surface on which the fuel gas passage is formed on the current collector plate 10. Thus, the workability can be improved.

  (7) Further, since the stacking direction of the stacked body 32 is set to a direction perpendicular to the gravity direction, in the lattice-shaped passages in the vicinity of the discharge holes 62 and 72 in the gas passage 50, moisture is placed below the gravity direction. Becomes movable. Accordingly, it is possible to reliably ensure the flow path of the reaction gas at least in the upper portion in the direction of gravity, and to effectively suppress the decrease in power generation efficiency due to the blockage of the passage due to moisture.

  (8) Further, among the manifolds 60A, 60B, 70A, 70B, the discharge manifolds 60B, 70B are arranged below the supply manifolds 60A, 70A in the direction of gravity. Moisture contained in the reaction gas can be quickly discharged to the downstream side by the action of gravity in addition to the supply pressure of the reaction gas and discharged from the discharge holes 62 and 72, thereby improving its drainage. it can.

In addition, the said embodiment can also be implemented by changing a structure as follows.
In the above-described embodiment, the relation described above with respect to the cross-sectional areas of the manifolds 60A, 60B, 70A, 70B of the oxidant gas passage 50 and the fuel gas passage (opening areas of the supply holes 61, 71 and the discharge holes 62, 72). The equations (Equation 2-1), (Equation 2-2), (Equation 3-1), and (Equation 3-2) are set so as to hold, respectively. You may make it set the said relationship about the passage cross-sectional area (opening area of a supply hole and a discharge hole) of each manifold corresponding to any one path | route among fuel gas paths.

  In the above embodiment, the total passage cross-sectional areas SG1, SG2 of the upstream portion 50A and the downstream portion 50C so that the relational expression (Formula 1) is established in both the oxidant gas passage 50 and the fuel gas passage. However, the above relationship may be set for the cross-sectional area of one of the oxidant gas passage 50 and the fuel gas passage.

  In the above embodiment, the current collector plate 10 has been described as being formed with both the oxidant gas passage 50 and the fuel gas passage. However, the current collector plate 10 has only one of these passages. It may be formed.

The top view of the current collection board used for the fuel cell concerning this embodiment. The disassembled perspective view of the cell of the fuel cell. The perspective view of the fuel cell. The graph which shows the relationship between the flow volume of the reactive gas in an oxidant gas passage, and the distance from a supply manifold entrance.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Current collecting plate, 12 ... Side plate, 20 ... Substrate, 22 ... Electrolyte membrane, 24 ... Reaction electrode, 30 ... Fuel cell, 31 ... Cell, 32 ... Laminate, 50 ... Oxidant gas passage, 50A ... Upstream part , 50B ... folded portion, 50C ... downstream portion, 51 ... parallel groove, 52 ... lattice groove, 53 ... parallel groove, 54 ... lattice groove, 61, 71 ... supply hole, 62, 72 ... discharge hole, 60A, 70A ... Supply manifold, 60B, 70B ... discharge manifold, 126a, 127a ... inlet, 126b, 127b ... outlet.

Claims (16)

A gas passage through which a reaction gas flows is formed on the laminated surface laminated on the electrolyte membrane provided with the reaction electrode, and the same gas passage as the supply hole for forming a supply manifold for distributing and supplying the reaction gas to the gas passage In the current collector plate of the fuel cell, each of which has a discharge manifold forming discharge hole for discharging the reaction gas of
The gas passage has a shape folded at the end of the current collector plate, and the opening area SA1 of the discharge hole in the current collector plate is set larger than the opening area SA2 of the supply hole in the current collector plate, A current collector plate for a fuel cell, characterized in that a passage cross-sectional area SA3 downstream of the folded portion is set smaller than a passage cross-sectional area SA4 upstream of the folded portion. The current collector plate has a rectangular shape, and the supply hole and the discharge hole are formed at one end of the current collector plate, and cooling water passes between the supply hole and the discharge hole at one end thereof. The current collector plate for a fuel cell according to claim 1, wherein water holes are formed. An inner surface of the supply hole opposite to the cooling water hole is formed on an extension of a side surface of the current collector plate in the upstream passage, and an end portion of the current collector plate in the upstream passage is formed. The current collector plate for a fuel cell according to claim 2, wherein an inner surface of the cooling water hole opposite to the supply hole is formed on an extension of a side surface opposite to the cooling water hole. The supply hole and the discharge hole are formed in a rectangular cross section, and the supply hole and the discharge hole are perpendicular to the side of the current collector plate where the supply hole and the discharge hole are formed. The current collecting plate of a fuel cell according to claim 3, wherein the lengths of the sides of the discharge holes are equal to each other. The ratio (SA1 / SA2) of the opening areas SA1 and SA2 of the discharge hole and the supply hole is set in a range of 1.0 <(SA1 / SA2) <3.0. The collector plate of the fuel cell as described. 6. The fuel cell assembly according to claim 1, wherein a portion in the vicinity of the discharge hole is formed as a lattice-shaped passage, and at least a part of the other portion is formed as a plurality of independent passages. Electric board. The ratio (SA3 / SA4) between the downstream-side passage sectional area SA3 and the upstream-side passage sectional area SA4 of the gas passage is set in a range of 0.3 <(SA3 / SA4) <1.0. The current collector plate of the fuel cell according to any one of 6. A fuel gas passage is formed on one of the laminated surfaces on both sides of the electrolyte membrane, and an oxidant gas passage is formed on the other as the gas passage. The fuel gas supply hole and the oxidant serve as the supply hole. A gas supply hole and a fuel gas discharge hole and an oxidant gas discharge hole as the discharge hole are formed, respectively, and a cooling water supply hole and a cooling water discharge hole as the cooling water hole are formed, respectively, The agent gas passage has a symmetrical shape around the bisector of the current collector plate, and the fuel gas supply hole and the oxidant gas supply hole, the fuel gas discharge hole and the oxidant gas discharge hole, and The current collector plate for a fuel cell according to any one of claims 2 to 7, wherein the cooling water supply hole and the cooling water discharge hole are respectively formed at symmetrical positions with respect to the bisector. A laminated body in which a plurality of electrolyte membranes and current collecting plates provided with reaction electrodes are laminated, and a reactive gas is provided in each gas passage formed between the electrolyte membrane and the current collecting plates inside the laminated body. In a fuel cell in which a supply manifold for distributing and supplying and a discharge manifold for discharging reaction gas in the same gas passage are formed along the stacking direction of the same stack,
The gas passage is formed to have a shape that is folded at an end portion of the current collector plate on the stack surface of the current collector plate on which the electrolyte membrane is laminated, and a passage cross-sectional area SB1 of the discharge manifold is formed of the supply manifold. A fuel cell, characterized in that it is set larger than the passage cross-sectional area SB2, and the passage cross-sectional area SB3 downstream from the folded portion is set smaller than the passage cross-sectional area SB4 upstream from the folded portion. The current collector plate has a rectangular shape, and the supply manifold and the discharge manifold are formed at one end of the current collector plate, and cooling water passes between the supply manifold and the discharge manifold at one end thereof. The fuel cell according to claim 9, wherein a water manifold is formed. An inner surface of the supply manifold opposite to the cooling water manifold is formed on an extension of a side surface of the current collector plate in the upstream passage, and an end portion of the current collector plate in the upstream passage is formed. The fuel cell according to claim 10, wherein an inner surface of the cooling water manifold opposite to the supply manifold is formed on an extension of a side surface opposite to the cooling water manifold. The supply manifold and the discharge manifold have a rectangular cross-sectional shape, and the supply manifold and the discharge manifold are perpendicular to the one end side of the current collector plate on which the supply manifold and the discharge manifold are formed. The fuel cell according to claim 11, wherein the lengths of the sides of the discharge manifold are equal to each other. The fuel cell according to any one of claims 9 to 12, wherein a ratio (SB1 / SB2) of passage cross-sectional areas SB1 and SB2 of each manifold is set in a range of 1.0 <(SB1 / SB2) <3.0. The fuel according to any one of claims 9 to 13, wherein the vicinity of the communicating portion with the exhaust manifold is formed as a lattice-shaped passage, and at least a part of the other portion is formed as a plurality of independent passages. battery. The fuel cell according to claim 14, wherein the stacked body is formed by stacking a plurality of the electrolyte membranes and the current collector plates in a direction perpendicular to a gravitational direction. The ratio (SB3 / SB4) between the downstream-side passage sectional area SA3 and the upstream-side passage sectional area SB4 of the gas passage is set in a range of 0.3 <(SB3 / SB4) <1.0. 15. The fuel cell according to any one of 15.

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