JP2011253670A - Fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize quick stabilization of power generation especially at initiation.SOLUTION: A fuel cell 10 includes: an electrolyte membrane-electrode structure 12; a first metal separator 14; and a second metal separator 16. An oxidizer gas passage 30 is provided in the first metal separator 14. A fuel gas passage 34 is provided in the second metal separator 16. The oxidizer gas passage 30 is provided with a plurality of oxidizer gas passage grooves 30a. At least one of the oxidizer gas passage grooves 30a constitutes a passage part 33 for initiation through which oxidizer gas reaches an oxidizer gas outlet communication hole from an oxidizer gas inlet communication hole faster than through the other oxidizer gas passage grooves 30a.

Description

  In the present invention, an electrolyte / electrode structure provided with a pair of electrodes on both sides of an electrolyte and a separator are laminated, a reaction gas flow path for supplying a reaction gas is formed along the electrode surface, and the reaction gas is The present invention relates to a fuel cell in which a reaction gas inlet communication hole and a reaction gas outlet communication hole that are circulated in the stacking direction of the separator are formed.

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

  In the above fuel cell, a fuel gas channel (reactive gas channel) for flowing fuel gas is provided in the surface of one separator so as to face the anode side electrode, and in the surface of the other separator, An oxidant gas flow path (reaction gas flow path) for flowing an oxidant gas is provided facing the cathode side electrode. Further, for each fuel cell or for each of the plurality of fuel cells, a coolant flow path for flowing the coolant in the electrode range is formed along the surface direction of the separator.

  The fuel cell may constitute a so-called internal manifold fuel cell type in which reaction gas communication holes and cooling medium communication holes penetrating in the separator stacking direction are provided inside. For example, as shown in FIG. 12, the fuel cell stack disclosed in Patent Document 1 includes a unit cell 1, and the unit cell 1 includes separators 3 a and 3 b disposed on both surfaces of a membrane electrode structure 2. ing.

  A fuel gas supply port 4a and an oxidant gas supply port 5a, which are fluid communication holes, are provided at the upper end in the longitudinal direction of the unit cell 1 so as to penetrate in the stacking direction, and at the lower end in the longitudinal direction of the unit cell 1 The fuel gas discharge port 4b and the oxidant gas discharge port 5b, which are fluid communication holes, are formed penetrating in the stacking direction. At both ends in the short direction of the unit cell 1, four cooling water supply ports 6a and four cooling water discharge ports 6b, which are fluid communication holes, are arranged in the vertical direction.

  A surface of the separator 3a facing the membrane electrode structure 2 is formed with a plurality of undulating fuel gas passages 7a that communicate with the fuel gas supply port 4a and the fuel gas discharge port 4b and extend in the longitudinal direction. Yes. On the surface of the separator 3b facing the membrane electrode structure 2, there are a plurality of undulating oxidant gas channels 8a communicating with the oxidant gas supply port 5a and the oxidant gas discharge port 5b and extending in the longitudinal direction. Is formed.

  By laminating the unit cells 1, a cooling water flow path is formed between the separator 3 a configuring one unit cell 1 and the separator 3 b configuring the other unit cell 1. This cooling water flow path is formed by overlapping the groove shape 7b on the back surface side of the fuel gas flow path 7a and the groove shape 8b on the back surface side of the oxidant gas flow path 8a so that the cooling water flows in the short direction (horizontal direction). Allowing the flow, the cooling water supply port 6a and the cooling water discharge port 6b communicate with each other.

  On the surface of the separators 3a and 3b on the cooling water flow path side, a first seal portion 9a that surrounds and seals the fuel gas supply port 4a and the fuel gas discharge port 4b, and an oxidant gas supply port 5a and an oxidant gas discharge port. A second seal portion 9b that surrounds and seals 5b is provided. A surface of the separators 3a and 3b facing the membrane electrode structure 2 is provided with a third seal portion 9c that surrounds and seals the cooling water supply port 6a and the cooling water discharge port 6b. The first seal portion 9a, the second seal portion 9b, and the third seal portion 9c are set to have the same cross-sectional area, and are integrally formed with the metal separators 3a and 3b.

JP 2007-141552 A

  In the above-mentioned Patent Document 1, for example, in order to supply fuel gas to the anode side electrode of the membrane electrode structure 2, a plurality of wavy fuel gas flow paths 7a are provided. For this reason, it takes time for the fuel gas to reach the entire power generation surface, and there is a problem that sufficient generated power cannot be obtained particularly when the fuel cell vehicle is accelerated rapidly.

  In particular, when the fuel cell is started, air is present in the fuel gas passage 7a. Therefore, when power is generated in a state where fuel gas is supplied only from the fuel gas supply port 4a to the upper part of the fuel gas flow path 7a, the power generation possible region is small and the power generation state becomes unstable. Moreover, it takes time for the potential to stabilize, and there is a risk of deterioration due to exposure to a high potential.

  The present invention solves this type of problem, and an object of the present invention is to provide a fuel cell capable of achieving rapid stabilization of power generation particularly at the time of startup.

  In the present invention, an electrolyte / electrode structure provided with a pair of electrodes on both sides of an electrolyte and a separator are laminated, a reaction gas flow path for supplying a reaction gas is formed along the electrode surface, and the reaction gas is The present invention relates to a fuel cell in which a reaction gas inlet communication hole and a reaction gas outlet communication hole that are circulated in the stacking direction of the separator are formed.

  In this fuel cell, the reaction gas flow path has a plurality of reaction gas flow path grooves, and at least one of the reaction gas flow path grooves is formed such that the reaction gas is directed from the reaction gas inlet communication hole toward the reaction gas outlet communication hole. The starting flow path portion that reaches faster than the reaction gas flow path groove is formed.

  Moreover, in this fuel cell, it is preferable that the starting flow path portion has a portion having a smaller pressure loss than the other reaction gas flow path grooves.

  Further, in this fuel cell, the electrode has a gas diffusion layer, and the gas diffusion layer has a thickness of a portion arranged in the activation flow passage portion of a portion arranged in another reaction gas flow passage groove. It is preferable to set it smaller than the thickness.

  Furthermore, in this fuel cell, the start-up flow path portion has a plurality of wave-like reaction gas flow path grooves adjacent to each other, and the reaction gas flows into the reaction gas flow path grooves adjacent to each other. It is preferable to provide a branching portion for introducing into the channel groove.

  The reactive gas is preferably a fuel gas.

  According to the present invention, the reaction gas introduced into the start-up flow channel portion can reach the reaction gas outlet communication hole faster than the reaction gas introduced into the other reaction gas flow channel grooves. For this reason, the reactive gas reaches a wider area within the power generation surface more quickly, and power generation can be performed throughout the power generation surface even during rapid acceleration. Therefore, immediately after the start-up, stabilization of power generation is performed quickly, the potential of the fuel cell is stabilized well, the time of exposure to a high potential is shortened, and deterioration is reliably suppressed.

It is a principal part disassembled perspective explanatory drawing of the fuel cell which concerns on the 1st Embodiment of this invention. FIG. 2 is a sectional view of the fuel cell taken along line II-II in FIG. 1. It is explanatory drawing of the front of the 1st metal separator which comprises the said fuel cell. It is explanatory drawing of the front of the 2nd metal separator which comprises the said fuel cell. It is relationship explanatory drawing of time and electric potential of this invention and a comparative example. It is front explanatory drawing of the reaction gas flow path which comprises the fuel cell which concerns on the 2nd Embodiment of this invention. It is front explanatory drawing of the reaction gas flow path which comprises the fuel cell which concerns on the 3rd Embodiment of this invention. It is front explanatory drawing of the reaction gas flow path which comprises the fuel cell which concerns on the 4th Embodiment of this invention. It is front explanatory drawing of the reaction gas flow path which comprises the fuel cell which concerns on the 5th Embodiment of this invention. It is a principal part disassembled perspective explanatory drawing of the fuel cell which concerns on the 6th Embodiment of this invention. FIG. 11 is a cross-sectional explanatory view of the fuel cell taken along line XI-XI in FIG. 10. It is a disassembled perspective explanatory drawing of the unit cell currently disclosed by patent document 1. FIG.

  As shown in FIGS. 1 and 2, a plurality of fuel cells 10 according to the first embodiment of the present invention are stacked in the direction of arrow A (horizontal direction) to constitute a fuel cell stack 11. The fuel cell 10 includes an electrolyte membrane / electrode structure 12, and a first metal separator 14 and a second metal separator 16 that sandwich the electrolyte membrane / electrode structure 12.

  The first metal separator 14 and the second metal separator 16 are made of, for example, a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, or a metal plate whose surface has been subjected to anticorrosion treatment. The first metal separator 14 and the second metal separator 16 have a rectangular planar shape, and are formed into a concavo-convex shape by pressing a metal thin plate into a wave shape.

  In place of the first metal separator 14 and the second metal separator 16, for example, a first carbon separator (not shown) and a second carbon separator (not shown) may be used.

  As shown in FIG. 1, the first metal separator 14 and the second metal separator 16 have a vertically long shape (rectangular shape), the long side is directed in the direction of gravity (arrow C direction), and the short side is horizontal (arrow). B direction) (horizontal stacking). The first metal separator 14 and the second metal separator 16 may be configured such that the long side is directed in the horizontal direction and the short side is directed in the gravitational direction, and the separator surface is directed in the horizontal direction (vertical direction). May also be configured.

  An oxidant gas inlet communication hole 18a for supplying an oxidant gas, for example, an oxygen-containing gas, communicates with each other in the direction of the arrow A in the vicinity of the upper corners of the long side direction (arrow C direction) of the fuel cell 10. And a fuel gas inlet communication hole 20a for supplying a fuel gas, for example, a hydrogen-containing gas.

  In the vicinity of the lower corners of the long side direction of the fuel cell 10, the fuel gas outlet communication hole 20b for discharging the fuel gas and the oxidant gas for discharging the oxidant gas are communicated with each other in the arrow A direction. An outlet communication hole 18b is provided.

  Two cooling medium inlet communication holes 22 a for communicating with each other in the direction of arrow A and for supplying the cooling medium are provided at symmetrical positions above both edge portions in the short side direction (arrow B direction) of the fuel cell 10. In addition, two cooling medium outlet communication holes 22b for discharging the cooling medium are provided at symmetrical positions below both edge portions of the fuel cell 10.

  The electrolyte membrane / electrode structure 12 includes, for example, a solid polymer electrolyte membrane 24 in which a perfluorosulfonic acid thin film is impregnated with water, and a cathode side electrode 26 and an anode side electrode 28 that sandwich the solid polymer electrolyte membrane 24. With.

  As shown in FIG. 2, the cathode side electrode 26 and the anode side electrode 28 are composed of gas diffusion layers 26a and 28a made of carbon paper or the like, and porous carbon particles carrying platinum alloy on the surface thereof. And an electrode catalyst layer (not shown) formed uniformly on the surface of 28a. The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 24.

  As shown in FIG. 3, on the surface 14a of the first metal separator 14 facing the electrolyte membrane / electrode structure 12, an oxidant gas flow communicating the oxidant gas inlet communication hole 18a and the oxidant gas outlet communication hole 18b. A path 30 is formed. The oxidant gas flow path 30 has a plurality of wavy oxidant gas flow path grooves 30a formed between a plurality of wavy convex portions extending in the direction of arrow C, and the oxidant gas flow path 30 An inlet buffer portion 32a and an outlet buffer portion 32b each having a plurality of embosses are provided in the vicinity of the inlet and the outlet. The plurality of wavy oxidant gas flow channel grooves 30a have a uniform width dimension within the plane.

  In the first embodiment, among the plurality of oxidant gas flow channel grooves 30a, the two oxidant gas flow channel grooves 30a are sandwiched between the plurality of oxidant gas flow channel grooves 30a. A starting channel portion 33 is provided by the oxidant gas channel groove 30a. The start-up flow path portion 33 is configured by a predetermined oxidant gas flow path groove 30a, and the oxidant gas flows from the oxidant gas inlet communication hole 18a toward the oxidant gas outlet communication hole 18b to another oxidant gas. It has a function of reaching faster than the channel groove 30a.

  Specifically, as shown in FIGS. 2 and 3, the oxidant gas flow channel groove 30 a constituting the activation flow channel portion 33 is configured by smoothing the surface 14 a of the first metal separator 14. On the other hand, the other oxidant gas flow channel groove 30a is provided with a rough machining site RF on the surface 14a, so that the pressure loss of the oxidant gas in the oxidant gas flow channel groove 30a is set high. As shown in FIG. 3, the rough machining site RF is preferably provided between the upstream side of the oxidant gas flow path 30 and a predetermined height H.

  As shown in FIG. 1, the cooling medium having the back surface shape of the oxidant gas flow channel groove 30 a constituting the oxidant gas flow channel 30 is provided on the surface 14 b (the surface opposite to the surface 14 a) of the first metal separator 14. A channel groove 30b is provided. The cooling medium flow path groove 30b constitutes a part of a cooling medium flow path 38 to be described later.

  As shown in FIG. 4, on the surface 16a of the second metal separator 16 facing the electrolyte membrane / electrode structure 12, there is a fuel gas flow path 34 that connects the fuel gas inlet communication hole 20a and the fuel gas outlet communication hole 20b. It is formed. The fuel gas flow path 34 has a plurality of wavy fuel gas flow path grooves 34a formed between a plurality of wavy convex portions extending in the direction of arrow C, and the vicinity of the inlet of the fuel gas flow path 34 and In the vicinity of the outlet, an inlet buffer 36a and an outlet buffer 36b each having a plurality of embosses are provided. The plurality of wavy fuel gas channel grooves 34a have a uniform width dimension within the plane.

  In the first embodiment, two or more fuel gas passage grooves 34a are sandwiched between at least one fuel gas passage groove 34a among the plurality of fuel gas passage grooves 34a. The starting flow path portion 35 is configured by the gas flow path groove 34a.

  The starting flow path portion 35 is configured by smoothing the surface 16a of the second metal separator 16 corresponding to a predetermined fuel gas flow path groove 34a. The pressure loss of the fuel gas is set large by providing the rough processing part RF in the surface 16a in the other fuel gas flow channel 34a. The rough machining site RF is provided between a predetermined height H from the upstream side of the fuel gas channel 34.

  In addition, in order to increase the respective pressure losses in the predetermined oxidant gas flow channel groove 30a and the fuel gas flow channel groove 34a of the oxidant gas flow channel 30 and the fuel gas flow channel 34, in addition to the rough machining site RF, For example, you may comprise by sticking various friction generating members other than a raising material. Further, there is a case where it is not necessary to increase the pressure loss in the oxidant gas flow path 30, and only the fuel gas flow path 34 may be subjected to processing such as the rough machining portion RF. The same applies to the second and subsequent embodiments described below.

  Between the surface 16b of the second metal separator 16 and the surface 14b of the first metal separator 14, there is a cooling medium flow path 38 communicating with the cooling medium inlet communication holes 22a, 22a and the cooling medium outlet communication holes 22b, 22b. Formed (see FIG. 1 and FIG. 2). The cooling medium flow path 38 circulates the electrode range of the electrolyte membrane / electrode structure 12 and distributes the cooling medium in the direction of arrow C. An inlet buffer portion 40a and an outlet buffer portion 40b each having a plurality of embosses are provided in the vicinity of the inlet and the outlet of the cooling medium flow path 38.

  As shown in FIG. 1, a first seal member 42 is integrally formed on the surfaces 14 a and 14 b of the first metal separator 14 around the outer peripheral edge of the first metal separator 14. A second seal member 44 is integrally formed on the surfaces 16 a and 16 b of the second metal separator 16 around the outer peripheral edge of the second metal separator 16. As the first seal member 42 and the second seal member 44, for example, an elastic seal material such as EPDM, NBR, fluorine rubber, silicone rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroplane or acrylic rubber is used. A cushion material or a packing material is used.

  As shown in FIGS. 1 and 3, the surface 14 a of the first metal separator 14 has a plurality of holes that cut out the first seal member 42 to communicate the oxidant gas inlet communication hole 18 a and the oxidant gas flow path 30. A connecting passage 46a is formed. A plurality of connecting passages 46 b are formed on the surface 14 a so as to communicate the oxidant gas outlet communication hole 18 b and the oxidant gas flow path 30 by cutting out the first seal member 42.

  As shown in FIG. 4, a plurality of connecting passages 50 a are formed on the surface 16 a of the second metal separator 16 so as to communicate the fuel gas inlet communication hole 20 a and the fuel gas passage 34 by cutting out the second seal member 44. Is done. A plurality of connecting passages 50 b are formed in the surface 16 a so as to communicate the fuel gas outlet communication hole 20 b and the fuel gas passage 34 by cutting out the second seal member 44.

  As shown in FIG. 1, the surface 16 b of the second metal separator 16 has a plurality of connections that cut out the second seal member 44 to communicate the pair of cooling medium inlet communication holes 22 a and 22 a with the cooling medium flow path 38. A passage 52a is formed. A plurality of connecting passages 52b are formed in the surface 16b to cut out the second seal member 44 to communicate the pair of cooling medium outlet communication holes 22b, 22b with the cooling medium flow path 38.

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

  First, as shown in FIG. 1, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas inlet communication hole 18a, and a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas inlet communication hole 20a. Supplied. Further, a cooling medium such as pure water, ethylene glycol, or oil is supplied to the pair of cooling medium inlet communication holes 22a.

  Therefore, the oxidant gas is introduced into the oxidant gas flow path 30 of the first metal separator 14 from the oxidant gas inlet communication hole 18a as shown in FIG. The oxidant gas moves in the direction of arrow C (gravity direction) along the oxidant gas flow path 30 and is supplied to the cathode side electrode 26 of the electrolyte membrane / electrode structure 12.

  On the other hand, the fuel gas is supplied to the fuel gas flow path 34 of the second metal separator 16 from the fuel gas inlet communication hole 20a. As shown in FIG. 4, the fuel gas moves in the gravitational direction (arrow C direction) along the fuel gas flow path 34 and is supplied to the anode side electrode 28 of the electrolyte membrane / electrode structure 12.

  Therefore, in the electrolyte membrane / electrode structure 12, the oxidant gas supplied to the cathode side electrode 26 and the fuel gas supplied to the anode side electrode 28 are consumed by an electrochemical reaction in the electrode catalyst layer to generate power. Is done.

  Next, the oxidant gas supplied to and consumed by the cathode side electrode 26 of the electrolyte membrane / electrode structure 12 is discharged in the direction of arrow A along the oxidant gas outlet communication hole 18b. On the other hand, the fuel gas supplied to and consumed by the anode side electrode 28 of the electrolyte membrane / electrode structure 12 is discharged in the direction of arrow A along the fuel gas outlet communication hole 20b.

  The cooling medium supplied to the pair of cooling medium inlet communication holes 22a is introduced into the cooling medium flow path 38 between the first metal separator 14 and the second metal separator 16, as shown in FIG. The cooling medium once flows along the arrow B direction (horizontal direction) and then moves in the arrow C direction (gravity direction) to cool the electrolyte membrane / electrode structure 12. The cooling medium moves to both sides in the direction of arrow B and is then discharged to the pair of cooling medium outlet communication holes 22b.

  In this case, when the fuel cell 10 is stopped, air exists in the fuel gas flow path 34 by, for example, air scavenging. For this reason, when the fuel cell 10 is started, the fuel gas supplied from the fuel gas inlet communication hole 20a to the upstream side of the fuel gas passage 34 passes along each fuel gas passage groove 34a constituting the fuel gas passage 34. Therefore, it tends to flow relatively slowly toward the fuel gas outlet communication hole 20b.

  At that time, in the first embodiment, among the plurality of fuel gas flow channel grooves 34a, a predetermined number of the fuel gas flow channel grooves 34a are used for starting with smaller pressure loss than the other fuel gas flow channel grooves 34a. The flow path portion 35 is configured. Specifically, the friction coefficient of the fuel gas flow surface is increased by providing a rough machining portion RF in the fuel gas flow channel groove 34a other than the start flow channel portion 35.

  Therefore, as shown in FIG. 4, the fuel gas introduced from the fuel gas inlet communication hole 20a into the fuel gas passage 34 is preferentially introduced into the starting passage portion 35 having a small pressure loss. The fuel gas outlet communication hole 20b can be quickly reached along the fuel gas passage groove 34a constituting the passage portion 35.

  Accordingly, the fuel gas reaches a wider area within the power generation surface earlier, and power generation can be performed throughout the power generation surface even during rapid acceleration. As a result, immediately after startup, power generation is quickly stabilized, and the potential of the fuel cell 10 can be satisfactorily stabilized. Moreover, in the fuel cell 10, the time of exposure to a high potential is effectively shortened, and deterioration is reliably suppressed.

  Further, the rough machining portion RF of the fuel gas flow channel groove 34 a is provided in the range of a predetermined distance H on the upstream side of the fuel gas flow channel 34. For this reason, on the downstream side of the fuel gas passage 34, the friction coefficient of each fuel gas passage groove 34a becomes small. Therefore, the condensed water does not stay in the fuel gas channel groove 34a, and there is an advantage that good drainage can be maintained.

  In the oxidant gas flow path 30, as shown in FIG. 3, the oxidant gas flow path groove 30a having a rough processing portion RF and a large pressure loss is provided, similar to the fuel gas flow path 34 described above. And a starting flow path portion 33 including an oxidant gas flow path groove 30a having a flat shape and a small pressure loss.

  Therefore, the oxidant gas introduced into the oxidant gas flow path 30 from the oxidant gas inlet communication hole 18a can quickly reach the oxidant gas outlet communication hole 18b along the activation flow path portion 33. The same effect as the fuel gas flow path 34 can be obtained.

  FIG. 5 shows the results of detecting the starting potential in the fuel cell 10 of the first embodiment (the present invention) and a general fuel cell (comparative example) not provided with the roughened portion RF. . Thereby, in 1st Embodiment, fuel gas and oxidant gas can reach | attain rapidly compared with a comparative example with respect to the wide range in an electric power generation surface, and can obtain the stable electric potential in a short time. Become. Moreover, on the cathode side, the time of exposure to a high potential is effectively shortened as compared with the comparative example, and the effect that deterioration can be easily suppressed can be obtained.

  FIG. 6 is an explanatory front view of a reaction gas channel 70 constituting a fuel cell according to the second embodiment of the present invention.

  The reaction gas channel 70 can constitute only the fuel gas channel or both the fuel gas channel and the oxidant gas channel. The same applies to the third and subsequent embodiments described below.

  The reactive gas channel 70 has a plurality of wavy reactive gas channel grooves 70a formed between a plurality of wavy convex portions 70b extending in the direction of arrow C. A predetermined number (at least one) of the reaction gas flow channel grooves 70 a in the reaction gas flow channel groove 70 a constitutes the activation flow channel portion 72.

  In the starting flow path portion 72, a branching portion 74a is provided on the upstream side of the reaction gas flow channel groove 70a by notching the upper side of the inner corner portion of the wavy convex portion 70b bulging toward the reaction gas flow channel groove 70a. . On the downstream side of the reaction gas flow channel groove 70a, a branch portion 74b is provided by cutting out the upper corner portion of the wavy convex portion 70b that curves outward from the reaction gas flow channel groove 70a. The branch portions 74a and 74b are formed in advance by providing a portion that is not pressed when the corrugated convex portion 70b is pressed in the separator.

  In the second embodiment configured as described above, when the reaction gas (at least the fuel gas) is introduced into the reaction gas channel 70, the reaction gas is distributed to each reaction gas channel groove 70a. A part of the reaction gas supplied to the reaction gas flow channel groove 70a constituting the activation flow channel portion 72 is introduced into the adjacent reaction gas flow channel groove 70a through the branch portion 74a, while the remaining gas is supplied to the reaction gas flow channel groove 70a. The reaction gas flows in the direction of arrow C along the starting flow path.

  Accordingly, in the starting flow path portion 72, the flow rate of the reaction gas flowing through the reaction gas flow path groove 70a is reduced from the flow rate of the reaction gas flowing through the other reaction gas flow path groove 70a, so Can be distributed. As a result, the reaction gas reaches the wide range in the power generation surface earlier, and it is possible to perform power generation satisfactorily even during sudden acceleration, etc. can get.

  Further, on the downstream side of the starting flow path portion 72, the reaction gas is merged from the adjacent reaction gas flow path groove 70 a through the branch portion 74 b. For this reason, substantially the same amount of reaction gas flows through each reaction gas channel groove 70 a downstream of the reaction gas channel 70.

  FIG. 7 is an explanatory front view of a reaction gas channel 80 constituting a fuel cell according to the third embodiment of the present invention.

  The reactive gas flow path 80 has a plurality of wavy reactive gas flow path grooves 80a formed between a plurality of wavy convex portions extending in the direction of arrow C. At least one or more reactive gas flow channel grooves 80a constitute a starting flow channel portion 82 that reaches a wider area in the power generation surface earlier than the other reactive gas flow channel grooves 80a. The starting flow path portion 82 is configured by setting the flow path width S1 of the reaction gas flow path groove 80a to be larger than the flow path width S2 of the other reaction gas flow path grooves 80a.

  In the third embodiment configured as described above, the start-up flow path portion 82 is configured using the reaction gas flow path groove 80a having a flow path width S1 larger than the other reaction gas flow path grooves 80a. For this reason, the inflow amount of the reaction gas is increased in the starting flow path portion 82. Accordingly, the reaction gas can reach the wide range in the power generation surface earlier, and the same effect as in the first and second embodiments can be obtained.

  FIG. 8 is an explanatory front view of a reaction gas channel 90 constituting a fuel cell according to the fourth embodiment of the present invention, and FIG. 9 constitutes a fuel cell according to the fifth embodiment of the present invention. 2 is a front explanatory view of a reaction gas channel 100. FIG.

  As shown in FIG. 8, the reactive gas flow channel 90 has a plurality of wavy reactive gas flow channel grooves 90a formed between a plurality of wavy convex portions 90b extending in the direction of arrow C. At least one of the wavy convex portions 90b is integrally provided with a guide portion 90b1 extending upstream, so that the reaction gas flow channel groove 90a adjacent to the guide portion 90b1 is formed as a starting flow channel portion 94. Configure.

  As shown in FIG. 9, the reactive gas flow channel 100 has a plurality of wavy reactive gas flow channel grooves 100a formed between a plurality of wavy convex portions 100b extending in the direction of arrow C. The notch part 100b1 is provided at least at one or more upper ends of the plurality of wave-like convex parts 100b, so that the starting flow path part 102 having the reaction gas flow path groove 100a configured to have a short flow rate length is configured. Is done.

  In the fourth embodiment, the reaction gas is smoothly and rapidly introduced into the reaction gas flow channel groove 90a constituting the activation flow channel portion 94 under the guiding action of the guide portion 90b1, and the reaction gas is supplied to the power generation surface. It is possible to reach a wider area within a faster time.

  In the fifth embodiment, the starting flow path portion 102 is configured by the reaction gas flow path groove 100a having the notch portion 100b1, that is, having a short flow rate. In this starting flow path portion 102, the pressure loss is reduced as compared with the other reactive gas flow path grooves 100a, and the flow of the reactive gas is performed smoothly. Thereby, in 4th and 5th embodiment, the effect similar to said 1st-3rd embodiment is acquired.

  FIG. 10 is an exploded perspective view of the main part of a fuel cell 110 according to the sixth embodiment of the present invention. Note that the same components as those of the fuel cell 10 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The fuel cell 110 includes an electrolyte membrane / electrode structure 112 and a first separator 114 and a second separator 116 that sandwich the electrolyte membrane / electrode structure 112. The first separator 114 and the second separator 116 are constituted by, for example, a carbon separator or a metal separator.

  The first separator 114 has a plurality of linear oxidant gas passage grooves 118 formed between a plurality of linear protrusions extending in the direction of arrow C. Similarly, the second separator 116 has a plurality of linear fuel gas flow channel grooves 120 formed between a plurality of linear protrusions extending in the direction of arrow C.

  As shown in FIG. 11, corresponding to at least one of the oxidant gas flow channel grooves 118 among the plurality of oxidant gas flow channel grooves 118, a notch portion 122 is formed in the gas diffusion layer of the cathode side electrode 26. By providing the above, the starting flow path portion 124 is configured. Similarly, by providing a notch portion 126 in the gas diffusion layer constituting the anode side electrode 28 corresponding to at least one or more of the fuel gas flow channel grooves 120 among the plurality of fuel gas flow channel grooves 120, activation is performed. A flow path portion 128 is configured.

  Each gas diffusion layer is provided with the notched portions 122 and 126 so that the thickness of the portion disposed in the activation flow path portions 124 and 128 is different from that of the other oxidant gas flow path grooves 118 and fuel gas flow path grooves. The thickness is set to be smaller than the thickness of the portion arranged at 120. Notch portions 122 and 126 are provided extending in the direction of arrow C.

  In the sixth embodiment configured as described above, the notch part 122 is provided in the gas diffusion layer 26a of the cathode side electrode 26, so that the activation flow path part 124 is provided in a part having a smaller thickness than other parts. Is configured. Similarly, by providing the notch portion 126 in the gas diffusion layer 28a constituting the anode side electrode 28, the starting flow path portion 128 is configured corresponding to a portion having a smaller thickness than other portions.

  Therefore, the oxidant gas supplied to each oxidant gas flow channel groove 118 is quickly supplied to the electrode catalyst layer in the activation flow channel portion 124 and rapidly flows in the direction of arrow C to generate power. The reaction is carried out early. Similarly, the fuel gas supplied to each fuel gas flow channel groove 120 is rapidly supplied to the electrode catalyst layer in the activation flow channel portion 128 provided with the notch portion 126, and also in the direction of the arrow C. And flow quickly.

  As a result, the oxidant gas and the fuel gas reach the wide area in the power generation surface more quickly, and the stabilization of power generation is performed quickly, and the same effects as in the first to fifth embodiments described above. Is obtained.

DESCRIPTION OF SYMBOLS 10,110 ... Fuel cell 11 ... Fuel cell stack 12, 112 ... Electrolyte membrane and electrode structure 14, 16, 114, 116 ... Metal separator 18a ... Oxidant gas inlet communication hole 18b ... Oxidant gas outlet communication hole 20a ... Fuel Gas inlet communication hole 20b ... Fuel gas outlet communication hole 22a ... Cooling medium inlet communication hole 22b ... Cooling medium outlet communication hole 24 ... Solid polymer electrolyte membrane 26 ... Cathode side electrode 28 ... Anode side electrode 30 ... Oxidant gas flow path 30a 118 ... Oxidant gas flow channel 33, 35, 72, 82, 94, 102, 124, 128 ... Startup flow channel 34 ... Fuel gas flow channel 34a, 120 ... Fuel gas flow channel 38 ... Cooling medium flow Channels 42, 44 ... Seal members 70, 80, 90, 100 ... Reaction gas channels 70a, 80a, 90a, 100a ... Reaction gas channel grooves 70b, 90b, 100b Wavy convex portions 74a, 74b ... the branch portion 90b1 ... guide portion 122, 126 ... notch site

Claims (5)

An electrolyte / electrode structure provided with a pair of electrodes on both sides of the electrolyte and a separator are stacked, a reaction gas flow path for supplying a reaction gas along the electrode surface is formed, and the reaction gas is stacked on the separator. A fuel cell in which a reaction gas inlet communication hole and a reaction gas outlet communication hole that circulate in a direction are formed,
The reaction gas channel has a plurality of reaction gas channel grooves,
At least one of the reaction gas flow channel grooves is a starting flow channel portion in which the reaction gas reaches from the reaction gas inlet communication hole toward the reaction gas outlet communication hole faster than the other reaction gas flow channel grooves. A fuel cell comprising:   2. The fuel cell according to claim 1, wherein the starting flow path portion has a portion having a smaller pressure loss than the other reaction gas flow path grooves. The fuel cell according to claim 1, wherein the electrode has a gas diffusion layer,
In the fuel cell, the gas diffusion layer is set such that a portion disposed in the activation channel portion has a thickness smaller than a thickness of a portion disposed in the other reaction gas channel groove. . 2. The fuel cell according to claim 1, wherein the start-up flow path portion includes a plurality of the wavy reactive gas flow path grooves adjacent to each other.
2. The fuel cell according to claim 1, wherein the reaction gas channel grooves adjacent to each other are provided with branch portions for introducing the reaction gas into the reaction gas channel grooves.   The fuel cell according to any one of claims 1 to 4, wherein the reaction gas is a fuel gas.

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