JP2006066131A - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely obstruct staying of condensed water in a reaction gas outlet communication hole in simple constitution and ensure high power generation performance. <P>SOLUTION: An oxidant gas passage 36 is installed in a first metal separator 14, and an outlet side end group 38b communicating with an oxidant gas outlet communication hole 30b is installed in a plurality of oxidant gas passage grooves 36a constituting the oxidant gas passage 36. A plurality of outlet side end parts 38b1-38b5 arranged in the vertical direction are installed in the outlet side end group 38b, and oxidant gas is slantingly splayed from the outlet side end part 38b1 to the upper wall surface 40a of the oxidant gas outlet communication hole 30b. <P>COPYRIGHT: (C)2006,JPO&NCIPI

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 stacked in a horizontal direction, and between the electrolyte / electrode structure and one separator, A reaction gas flow path for supplying a reaction gas along the surface direction is formed, and a reaction gas outlet communication hole penetrating in the stacking direction and communicating with a plurality of outlet side end portions of the reaction gas flow path is formed. The present invention relates to a fuel cell.

  For example, a solid polymer fuel cell employs a solid polymer electrolyte membrane made of a polymer ion exchange membrane. This fuel cell has an electrolyte membrane / electrode structure in which an anode side electrode and a cathode side electrode each made of an electrode catalyst (electrode catalyst layer) and porous carbon (diffusion layer) are provided on both sides of a solid polymer electrolyte membrane. A power generation cell sandwiched between separators (bipolar plates) is formed. Usually, in a fuel cell, a fuel cell stack in which a predetermined number of power generation cells are stacked is used.

  In this type of fuel cell, the anode side electrode is supplied with a fuel gas (reactive gas), for example, a gas mainly containing hydrogen (hereinafter also referred to as hydrogen-containing gas), while the cathode side electrode An oxidant gas (reactive gas), for example, a gas mainly containing oxygen or air (hereinafter also referred to as oxygen-containing gas) is supplied. In the fuel gas supplied to the anode side electrode, hydrogen is ionized on the electrode catalyst and moves to the cathode side electrode side through the electrolyte membrane. Electrons generated during that time are taken out to an external circuit and used as direct current electric energy.

  In the above fuel cell, an internal manifold is often configured to supply a fuel gas and an oxidant gas, which are reaction gases, to the anode side electrode and the cathode side electrode of each of the stacked power generation cells. The internal manifold includes a reaction gas inlet communication hole and a reaction gas outlet communication hole provided so as to penetrate in the stacking direction of the power generation cells, and a reaction gas flow path (oxidant gas) for supplying the reaction gas along the electrode surface. The reaction gas inlet communication hole and the reaction gas outlet communication hole communicate with the inlet and the outlet of the flow channel and the fuel gas flow channel, respectively.

  By the way, in the oxidant gas flow path through which the oxidant gas flows, reaction product water is generated during power generation, while in the fuel gas flow path through which the fuel gas flows, condensed water is generated due to reverse diffusion or condensation of the reaction product water. Easy to do. At this time, if the condensed water adheres to the oxidant gas flow path or the fuel gas flow path, the flow of the oxidant gas or the fuel gas is hindered, causing a decrease in power generation performance. For this reason, it is necessary to reliably discharge condensed water from the oxidant gas flow path and the fuel gas flow path to the oxidant gas outlet communication hole and the fuel gas outlet communication hole (reaction gas outlet communication hole), respectively.

  Therefore, for example, the polymer electrolyte fuel cell disclosed in Patent Document 1 includes a battery plate (separator) 1 as shown in FIG. In the battery plate 1, a reactive gas, for example, an oxidant flow path 2 is bent in a meandering manner, and the lower end portion of the oxidant flow path 2 is a flow path inlet 2a and the upper end is a flow path outlet 2b. The flow path inlet 2 a communicates with the oxidant supply manifold 3, while the flow path outlet 2 b communicates with the oxidant discharge manifold 4.

  The oxidant supply manifold 3 has a groove shape and is elongated in the vertical direction, and a supply port 3 a is provided through the battery plate 1 at an upper portion thereof. Similarly, the oxidant discharge manifold 4 has a concave groove shape and is elongated in the vertical direction, and a discharge port 4a is provided through the battery plate 1 at a lower portion thereof.

  In such a configuration, when moisture is condensed in the oxidant flow path 2 during power generation and condensed water 5 is generated, the condensed water 5 moves downward along the oxidant discharge manifold 4 from the flow path outlet 2b, It collects in the lower end part of the discharge port 4a. At this time, since the discharge port 4a is located below the channel outlet 2b for the oxidant gas, the channel outlet 2b is not blocked by the condensed water 5 and is oxidized in the oxidant channel 2. The flow of the agent gas is not blocked and good power generation performance can be maintained.

Japanese Patent Laying-Open No. 2003-223922 (FIG. 1)

  However, in Patent Document 1 described above, since the oxidant gas is not sprayed onto the upper wall surface 4b of the oxidant exhaust manifold 4, water droplets are generated on the upper wall surface 4b and the condensed water 5a tends to stay. Further, the condensed water 5a may also stay on the upper side of the side wall surface 4c of the oxidant exhaust manifold 4 due to water droplet formation. As a result, the flow path area of the oxidant discharge manifold 4 is reduced, and there is a problem that smooth exhaust of the oxidant gas is not performed.

  The present invention solves this type of problem, and with a simple configuration, it is possible to reliably prevent the condensate from staying in the reaction gas outlet communication hole and to ensure good power generation performance. An object of the present invention is to provide a simple fuel cell.

  In the present invention, an electrolyte / electrode structure provided with a pair of electrodes on both sides of an electrolyte and a separator are stacked in a horizontal direction, and between the electrolyte / electrode structure and one separator, A reaction gas flow path for supplying a reaction gas along the surface direction is formed, and a reaction gas outlet communication hole penetrating in the stacking direction and communicating with a plurality of outlet side end portions of the reaction gas flow path is formed. It is a fuel cell.

  In this fuel cell, the flow direction of the reaction gas from the plurality of outlet side end portions of the reaction gas channel toward the reaction gas outlet communication hole is inclined at least partially with respect to the wall surface forming the reaction gas outlet communication hole. ing.

  The plurality of outlet side end portions of the reaction gas flow path are arranged in the vertical direction, and are inclined at least from the uppermost outlet side end portion with respect to the upper wall surface forming the reaction gas outlet communication hole. Is preferably sprayed.

  Furthermore, it is preferable that a recess is provided on the lower side of the wall surface forming the reaction gas outlet communication hole so as to protrude below the outlet side end of the reaction gas flow path.

  Furthermore, in the present invention, an electrolyte / electrode structure in which a pair of electrodes are provided on both sides of an electrolyte and a separator are stacked in a horizontal direction, and between the electrolyte / electrode structure and one separator, A reaction gas flow path for supplying a reaction gas along the surface direction of the electrode is formed, and a reaction gas outlet communication hole penetrating in the stacking direction and communicating with a plurality of outlet side end portions of the reaction gas flow path is formed. It is a fuel cell to be formed.

  In this fuel cell, a recess is provided on the lower side of the wall surface that forms the reaction gas outlet communication hole and protrudes below the outlet side end of the reaction gas flow path.

  According to the present invention, since the reaction gas is sprayed with an inclination to the wall surface of the reaction gas outlet communication hole, the reaction gas flow can be smoothly distributed along the wall surface, and water droplets can be formed on the wall surface. Well blocked. Thereby, it is possible to reliably prevent the condensed water from staying in the reaction gas outlet communication hole with a simple configuration, and it is possible to ensure good power generation performance.

  Further, the condensed water discharged to the reaction gas outlet communication hole moves to the concave portion on the lower side of the wall surface of the reaction gas outlet communication hole by the reaction gas flow from the reaction gas flow path. For this reason, the condensed water and the gas flow in the reaction gas outlet communication hole do not hinder the discharge of the gas flow from the reaction gas channel. In addition, it is possible to prevent the condensed water from scattering into the reaction gas flow path, and to effectively prevent the reaction gas flow path from being blocked.

  FIG. 1 is an exploded perspective view of a main part of a fuel cell 10 according to the first embodiment of the present invention. The fuel cell 10 is formed by laminating an electrolyte membrane / electrode structure (electrolyte / electrode structure) 12 and first and second metal separators 14 and 16 in the horizontal direction (arrow A direction). Configure the stack. For example, a carbon separator may be used instead of the first and second metal separators 14 and 16.

  The electrolyte membrane / electrode structure 12 includes, for example, a solid polymer electrolyte membrane 18 in which a perfluorosulfonic acid thin film is impregnated with water, and an anode side electrode 20 and a cathode side electrode 22 that sandwich the solid polymer electrolyte membrane 18. With.

  The anode side electrode 20 and the cathode side electrode 22 are uniformly coated on the surface of the gas diffusion layer with a gas diffusion layer (not shown) made of carbon paper or the like and porous carbon particles carrying platinum alloy on the surface. An electrode catalyst layer (not shown).

  One end edge of the fuel cell 10 in the direction of arrow B communicates with each other in the direction of arrow A, which is the stacking direction, and an oxidant gas inlet communication hole 30a for supplying an oxidant gas, for example, an oxygen-containing gas, A cooling medium inlet communication hole 32a for supplying a medium, and a fuel gas outlet communication hole (reactive gas outlet communication hole) 34b for discharging a fuel gas, for example, a hydrogen-containing gas, are provided in the arrow C direction (vertical direction). Arranged and provided.

  The other end edge of the fuel cell 10 in the direction of arrow B communicates with each other in the direction of arrow A, a fuel gas inlet communication hole 34a for supplying fuel gas, and a cooling medium outlet communication hole for discharging the cooling medium. 32b and an oxidant gas outlet communication hole (reaction gas outlet communication hole) 30b for discharging the oxidant gas are arranged in the direction of arrow C.

  As shown in FIGS. 1 and 2, an oxidizing gas channel (reactive gas channel) 36 is provided on the surface 14 a of the first metal separator 14 facing the electrolyte membrane / electrode structure 12. The oxidant gas flow channel 36 has a plurality of oxidant gas flow channel grooves 36a, and the oxidant gas flow channel grooves 36a extend in the direction of arrow B. Note that the oxidant gas flow channel 36a may constitute, for example, a serpentine flow channel that folds back and forth halfway in the direction of arrow B.

  The oxidant gas channel groove 36a communicates with the oxidant gas inlet communication hole 30a through the inlet side end group 38a, and communicates with the oxidant gas outlet communication hole 30b through the outlet side end group 38b.

  As shown in FIG. 3, the outlet side end group 38b has a plurality of outlet side ends 38b1, 38b2, 38b3, 38b4, and 38b5 arranged in the vertical direction (the direction of arrow C). The uppermost outlet side end 38b1 is inclined at an angle θ1 ° upward from the horizontal direction, and is set so that the oxidant gas can be blown from the oblique direction onto the upper wall surface 40a forming the oxidant gas outlet communication hole 30b. .

  The outlet side end 38b2 is inclined upward by an angle θ2 ° from the horizontal direction and is inclined with respect to the side wall surface 40b forming the oxidant gas outlet communication hole 30b, or alternatively, the side wall surface 40b and the upper wall surface 40a. It is comprised so that oxidizing gas may be sprayed toward the boundary part vicinity.

  The outlet side end 38b3 is oriented in the horizontal direction, while the outlet side end 38b4 is inclined at an angle θ3 ° downward from the horizontal direction. The lowermost outlet side end portion 38b5 is inclined at an angle θ4 ° downward from the horizontal direction, and the outlet side end portions 38b4 and 38b5 are set in an oxidant gas flow direction inclined with respect to the side wall surface 40b. .

  On the lower side of the wall surface constituting the oxidant gas outlet communication hole 30b, a concave part 42 having an arcuate cross section is provided so as to protrude below the outlet side end 38b5 located at the lowermost part of the oxidant gas flow path 36.

  As shown in FIG. 4, a fuel gas flow path (reactive gas flow path) 48 is provided on the surface 16 a of the second metal separator 16 facing the electrolyte membrane / electrode structure 12. The fuel gas channel 48 has a plurality of fuel gas channel grooves 48 a extending in the direction of arrow B, like the oxidant gas channel 36. The fuel gas channel groove 48a communicates with the fuel gas inlet communication hole 34a through the inlet side end group 50a, and communicates with the fuel gas outlet communication hole 34b through the outlet side end group 50b.

  The fuel gas outlet communication hole 34b and the outlet side end group 50b are configured in the same manner as the oxidant gas outlet communication hole 30b and the outlet side end group 38b, and the same components are referred to by the same reference. Reference numerals are assigned and detailed description thereof is omitted.

  The first metal separator 14 and the second metal separator 16 integrally form a cooling medium flow path 52 on the surfaces 14b, 16b facing each other (see FIG. 1). The cooling medium flow path 52 is formed integrally with the back surface side of the oxidant gas flow path 36 and the back surface side of the fuel gas flow path 48, and has a plurality of cooling medium flow path grooves 52a extending in the arrow B direction. . The cooling medium flow path 52 communicates with the cooling medium inlet communication hole 32a and the cooling medium outlet communication hole 32b.

  A first seal member 54 is integrally provided on the surfaces 14a and 14b of the first metal separator 14 by injection molding or the like around the outer peripheral edge of the first metal separator 14. The first seal member 54 covers the oxidant gas inlet communication hole 30a, the oxidant gas outlet communication hole 30b, and the oxidant gas flow path 36 on the surface 14a to prevent leakage of the oxidant gas.

  A second seal member 56 is integrally provided on the surfaces 16a and 16b of the second metal separator 16 by injection molding or the like around the outer peripheral edge of the second metal separator 16. As shown in FIG. 4, the second seal member 56 covers the fuel gas inlet communication hole 34 a, the fuel gas outlet communication hole 34 b, and the fuel gas flow path 48 on the surface 16 a to prevent leakage of fuel gas. As shown in FIG. 1, the second seal member 56 covers the cooling medium inlet communication hole 32 a, the cooling medium outlet communication hole 32 b, and the cooling medium flow path 52 on the surface 16 b to prevent leakage of the cooling medium.

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

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

  The oxidant gas is introduced into the oxidant gas flow path 36 of the first metal separator 14 from the oxidant gas inlet communication hole 30a. In the oxidant gas flow path 36, as shown in FIG. 2, the oxidant gas is dispersed in the plurality of oxidant gas flow path grooves 36a. Therefore, the oxidant gas moves along the cathode side electrode 22 of the electrolyte membrane / electrode structure 12 through each oxidant gas flow channel 36a.

  On the other hand, the fuel gas is introduced into the fuel gas passage 48 of the second metal separator 16 from the fuel gas inlet communication hole 34a. In the fuel gas channel 48, as shown in FIG. 4, the fuel gas is dispersed in a plurality of fuel gas channel grooves 48a. Further, the fuel gas moves along the anode side electrode 20 of the electrolyte membrane / electrode structure 12 through each fuel gas flow channel groove 48a.

  Therefore, in the electrolyte membrane / electrode structure 12, the oxidant gas supplied to the cathode side electrode 22 and the fuel gas supplied to the anode side electrode 20 are consumed by an electrochemical reaction in the electrode catalyst layer to generate power. Is done.

  Next, the oxidant gas consumed by being supplied to the cathode side electrode 22 is discharged to the oxidant gas outlet communication hole 30b (see FIGS. 1 and 2). Similarly, the fuel gas supplied to and consumed by the anode side electrode 20 is discharged to the fuel gas outlet communication hole 34b (see FIG. 4).

  On the other hand, the cooling medium supplied to the cooling medium inlet communication hole 32a is introduced into the cooling medium flow path 52 formed between the first and second metal separators 14 and 16 (see FIG. 1). In the cooling medium flow path 52, the cooling medium moves in the horizontal direction (arrow B direction). Therefore, the cooling medium is cooled over the entire power generation surface of the electrolyte membrane / electrode structure 12 and then discharged to the cooling medium outlet communication hole 32b.

  In this case, in the first embodiment, as shown in FIG. 3, for example, in the outlet side end group 38 b of the oxidant gas flow path 36, a plurality of outlet side ends 38 b 1 to 38 b 5 arranged in the vertical direction are arranged. In addition, at least the uppermost outlet side end portion 38b1 is inclined by an angle θ1 ° from the horizontal direction to the vertical upward direction.

  For this reason, the flow direction of the oxidant gas from the outlet side end 38b1 toward the oxidant gas outlet communication hole 30b is directed in a direction inclined with respect to the upper wall surface 40a. Accordingly, the oxidant gas discharged from the outlet side end 38b1 to the oxidant gas outlet communication hole 30b is inclined and blown to the upper wall surface 40a, so that the oxidant gas flow smoothly flows along the upper wall surface 40a. Water droplets can be satisfactorily prevented from condensing water on the upper wall surface 40a.

  That is, since the oxidant gas flow is directly blown from the oblique direction to the upper wall surface 40a, the moisture adhering to the upper wall surface 40a moves in the arrow direction along the side wall surface 40b from the upper wall surface 40a. Water droplet formation on the wall surface 40a is prevented.

  Further, the side wall surface 40b adheres to the side wall surface 40b by the oxidant gas blown obliquely from the outlet side end portion 38b2 and by the oxidant gas blown obliquely downward from the outlet side end portions 38b4 and 38b5. Moisture that moves moves downward. Accordingly, it is possible to prevent water droplets from being generated on the side wall surface 40b.

  Accordingly, in the first embodiment, the reaction gas flow directions of the outlet side end portions 38b1 to 38b5 need only be set corresponding to the upper wall surface 40a and the side wall surface 40b. It is possible to reliably prevent the condensed water from staying in the gas outlet communication hole 30b, and the effect of ensuring good power generation performance can be obtained.

  Furthermore, in the first embodiment, a recess 42 is provided on the lower side of the oxidant gas outlet communication hole 30b so as to protrude below the outlet side end group 38b. For this reason, the condensed water and the oxidant gas that move in the arrow direction by the oxidant gas flow discharged from the outlet side end group 38 b to the oxidant gas outlet communication hole 30 b move to the recess 42.

  Accordingly, since the condensed water flow and the oxidant gas flow in the oxidant gas outlet communication hole 30b swirl in the recess 42, in particular, the oxidant gas is discharged from the outlet side end 38b5 to the oxidant gas outlet communication hole 30b. There is no hindrance. This is because the condensed water flow and the oxidant gas flow do not flow backward to the outlet side end portion 38b5. In addition, the condensed water does not scatter to the outlet side end portion 38b5, and the blockage of the outlet side end portion 38b5 can be effectively avoided.

  In the fuel gas outlet communication hole 34b and the outlet side end group 50b, the same effects as those in the oxidant gas outlet communication hole 30b and the outlet side end group 38b are obtained.

  FIG. 5 is an enlarged explanatory view of a main part of the first metal separator 60 constituting the fuel cell according to the second embodiment of the present invention. In addition, the same referential mark is attached | subjected to the component same as the 1st metal separator 14 which comprises the fuel cell 10 which concerns on 1st Embodiment, and the detailed description is abbreviate | omitted.

  The outlet side end group 62 of the oxidant gas flow path 36 has a plurality of outlet side ends 62a to 62e arranged in the vertical direction. The outlet side end portions 62a to 62d have the oxidant gas flow direction oriented in the horizontal direction, while the outlet side end portion 62e tilts the oxidant gas flow direction from the horizontal direction vertically downward by an angle θ5 °. .

  The upper wall surface 64a of the oxidant gas outlet communication hole 30b is inclined from the horizontal direction, and the oxidant gas discharged from the outlet side end portions 62a and 62b is sprayed to the upper wall surface 64a.

  The side wall surfaces 64b and 64c of the oxidant gas outlet communication hole 30b are inclined with respect to the vertical direction, and the oxidant gas discharged from the outlet side end portions 62c, 62d and 62e is applied to the side wall surfaces 64b and 64c. It is sprayed at an angle. Since the upper wall surface 64a and the side wall surfaces 64b and 64c are formed to be inclined, the oxidant gas flow and the condensed water flow are smoothly moved along the upper wall surface 64a and the side wall surfaces 64b and 64c. A recess 66 is provided on the lower side of the oxidant gas outlet communication hole 30 b so as to protrude below the outlet side end group 62.

  In the second embodiment configured as described above, when the oxidant gas is discharged from the outlet side end portions 62a to 62e to the oxidant gas outlet communication hole 30b, the oxidant gas is separated from the upper wall surface 64a and the side wall surface. 64b is inclined and sprayed. For this reason, there are no water droplets in which condensed water stays on the upper wall surface 64a and the side wall surface 64b, and the retention of condensed water can be reliably prevented with a simple configuration, as in the first embodiment. The effect is obtained.

It is a principal part disassembled perspective view of the fuel cell which concerns on the 1st Embodiment of this invention. It is front explanatory drawing of the 1st metal separator which comprises the said fuel cell. It is principal part expansion explanatory drawing of a said 1st metal separator. It is front explanatory drawing of the 2nd metal separator which comprises the said fuel cell. It is principal part expansion explanatory drawing of the 1st metal separator which comprises the fuel cell which concerns on the 2nd Embodiment of this invention. FIG. 3 is a front explanatory view of a battery plate constituting the polymer electrolyte fuel cell of Patent Document 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fuel cell 12 ... Electrolyte membrane and electrode structure 14, 16, 60 ... Metal separator 18 ... Solid polymer electrolyte membrane 20 ... Anode side electrode 22 ... Cathode side electrode 30a ... Oxidant gas inlet communication hole 30b ... Oxidant gas Outlet communication hole 32a ... Cooling medium inlet communication hole 32b ... Cooling medium outlet communication hole 34a ... Fuel gas inlet communication hole 34b ... Fuel gas outlet communication hole 36 ... Oxidant gas channel 36a ... Oxidant gas channel grooves 38a, 50a ... Inlet side end group 38b, 50b, 62 ... Outlet side end group 38b1-38b5, 62a-64e ... Outlet side end 40a, 64a ... Upper wall surface 40b, 64b, 64c ... Side wall surface 42, 66 ... Recess 48 ... Fuel Gas passage 48a ... Fuel gas passage groove 52 ... Cooling medium passage

Claims (4)

An electrolyte / electrode structure provided with a pair of electrodes on both sides of the electrolyte and a separator are stacked in a horizontal direction, and the electrolyte / electrode structure and one separator are disposed along the surface direction of the electrode. In this fuel cell, a reaction gas flow path for supplying a reaction gas is formed, and a reaction gas outlet communication hole penetrating in the stacking direction and communicating with a plurality of outlet side end portions of the reaction gas flow path is formed. And
The fuel cell is characterized in that at least a part of the flow direction of the reaction gas from the plurality of outlet side end portions toward the reaction gas outlet communication hole is inclined with respect to a wall surface forming the reaction gas outlet communication hole. . The fuel cell according to claim 1, wherein the plurality of outlet side end portions are arranged in a vertical direction,
The fuel cell is characterized in that the reaction gas is sprayed at an inclination from at least the uppermost outlet side end portion to an upper wall surface forming the reaction gas outlet communication hole.   3. The fuel cell according to claim 1, wherein a recess is provided on the lower side of the wall surface forming the reaction gas outlet communication hole so as to protrude below the end portion on the outlet side. 4. An electrolyte / electrode structure provided with a pair of electrodes on both sides of the electrolyte and a separator are stacked in a horizontal direction, and the electrolyte / electrode structure and one separator are disposed along the surface direction of the electrode. In this fuel cell, a reaction gas flow path for supplying a reaction gas is formed, and a reaction gas outlet communication hole penetrating in the stacking direction and communicating with a plurality of outlet side end portions of the reaction gas flow path is formed. And
A fuel cell, characterized in that a recess is provided on the lower side of the wall surface forming the reaction gas outlet communication hole so as to protrude below the end on the outlet side.

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