JP7120969B2 - fuel cell system - Google Patents

Description

The present invention relates to fuel cell systems.

A fuel cell system includes a fuel cell stack having a cell stack in which a plurality of power generation cells are stacked. The power generation cell is formed with a reaction gas flow path for flowing a reaction gas along the power generation surface. The cell stack is formed with a discharge communication hole extending in the stacking direction of the power generating cells for discharging the reaction exhaust gas guided from the reaction gas channel. In some cases, generated water generated during power generation of the power generating cell is led to the discharge communication hole from the reactant gas flow path and remains in the discharge communication hole as stagnant water. In addition, condensed water may exist as stagnant water in the discharge communication hole.

For example, Patent Literature 1 discloses a configuration in which a drain (drainage flow path) for discharging stagnant water in a discharge communication hole is formed through a laminate. Water remaining in the drain is sucked out of the fuel cell stack by a venturi structure provided at the connection between the drain and the discharge communication hole.

JP 2012-226896 A

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fuel cell system capable of smoothly discharging stagnant water in a drain with a simple structure.

A first aspect of the present invention includes a fuel cell stack having a cell stack in which a plurality of power generation cells each having a reaction gas flow path along a power generation surface are stacked, and the cell stack includes: , a discharge communication hole for discharging the reaction exhaust gas guided from the reaction gas flow path, and a drain communicating with the discharge communication hole for discharging the accumulated water in the discharge communication hole, the power generation cell. Insulators and end plates are sequentially arranged outward in the stacking direction at both ends of the cell stack in the stacking direction, and the A plurality of discharge communication holes are provided, and the fuel cell stack is provided with a plurality of gas lead-out paths communicating with the plurality of discharge communication holes to lead out the reaction exhaust gas. is provided with a reduced flow channel portion having a flow channel cross-sectional area smaller than the flow channel cross-sectional area of the plurality of discharge communication holes, and the reduced flow channel portion is provided in the insulator or the end plate of the fuel cell stack. In the fuel cell system, the reaction exhaust gas in the plurality of discharge communication holes, the pressure of which is increased by the contracted passage portion, pushes out the water remaining in the drain.

A second aspect of the present invention includes a fuel cell stack having a cell stack in which a plurality of power generation cells are stacked, each of which has a reaction gas flow path for flowing a reaction gas along a power generation surface. , a discharge communication hole for discharging the reaction exhaust gas guided from the reaction gas flow path, and a drain communicating with the discharge communication hole for discharging the accumulated water in the discharge communication hole, the power generation cell. In the fuel cell system, a plurality of the discharge communication holes are provided, and the fuel cell stack is provided with a plurality of the discharge communication holes to lead out the reaction exhaust gas through the plurality of the discharge communication holes. A plurality of gas lead-out paths are provided, the fuel cell system has a gas-liquid separation unit for separating the gas and liquid of the reaction exhaust gas led from the plurality of gas lead-out paths, and each of the plurality of gas lead-out paths is , a connection channel that connects the end plate of the fuel cell stack and the gas-liquid separation unit to each other, the connection channel having a channel cross-sectional area smaller than the channel cross-sectional area of the plurality of discharge communication holes is provided, and the reaction exhaust gas in the plurality of discharge communication holes whose pressure is increased by the reduced flow path pushes out the stagnant water in the drain.
A third aspect of the present invention is provided with a fuel cell stack having a cell stack in which a plurality of power generation cells each having a reaction gas flow path along a power generation surface are stacked, and the cell stack includes: , a discharge communication hole for discharging the reaction exhaust gas guided from the reaction gas flow path, and a drain communicating with the discharge communication hole for discharging the accumulated water are arranged along the stacking direction of the power generation cells. A fuel cell system having a penetrating structure, comprising: a gas-liquid separation section for gas-liquid separation of the reaction exhaust gas led from the discharge communication hole; and a drain for discharging the liquid water separated by the gas-liquid separation section. a channel, a drain valve for opening and closing the drain channel, and a water lead-out channel for guiding the accumulated water in the drain to an upstream side of the drain valve in the drain channel, the drain channel has a reduced flow passage portion that generates a differential pressure such that, when the drain passage is opened by the drain valve, the accumulated water in the drain is led to the drain passage through the water lead-out passage. It is a fuel cell system provided.

According to one aspect of the present invention, since the pressure of the reaction exhaust gas in the plurality of discharge passages can be increased by the plurality of reduced flow passage portions, the accumulated water in the drain can be pushed out by the reaction exhaust gas in the discharge passages. can be done. As a result, the water remaining in the drain can be smoothly discharged with a simple structure.

According to another aspect of the present invention, when the drainage channel is opened by the drain valve, a pressure difference is generated by the contracted flow channel portion, so that the accumulated water in the drain can be guided to the drainage channel. Therefore, the water remaining in the drain can be smoothly discharged with a simple structure.

1 is a schematic configuration diagram of a fuel cell system according to a first embodiment of the present invention; FIG. FIG. 2 is an exploded perspective view of the power generation cell of FIG. 1; 2 is a partial cross-sectional view of the fuel cell system of FIG. 1; FIG. FIG. 2 is an explanatory view of the water drainage operation of the fuel cell system of FIG. 1; FIG. 2 is a schematic configuration diagram of a fuel cell system according to a second embodiment of the invention; FIG. 6 is an explanatory view of the water discharge operation of the fuel cell system of FIG. 5; FIG. 5 is a schematic configuration diagram of a fuel cell system according to a third embodiment of the present invention; FIG. 8 is an explanatory view of the water drainage operation of the fuel cell system of FIG. 7;

BEST MODE FOR CARRYING OUT THE INVENTION A preferred embodiment of a fuel cell system according to the present invention will be described below with reference to the accompanying drawings.

(First embodiment)
A fuel cell system 10A according to the first embodiment of the present invention is mounted, for example, on a fuel cell electric vehicle (not shown). However, the fuel cell system 10A can also be used as a stationary type.

As shown in FIG. 1, the fuel cell system 10A includes a fuel cell stack 12 and a fuel gas supply device 14 that supplies fuel gas. Although not shown, the fuel cell system 10A includes an oxidant gas supply device that supplies the fuel cell stack 12 with the oxidant gas and a cooling medium supply device that supplies the fuel cell stack 12 with the cooling medium.

The fuel cell stack 12 includes a cell stack 18 in which a plurality of power generation cells 16 are stacked horizontally (in the direction of arrow A). A terminal plate 20a, an insulator 22a and an end plate 24a are sequentially arranged outward at one end of the cell stack 18 in the stacking direction. A terminal plate 20b, an insulator 22b, and an end plate 24b are sequentially arranged outward at the other end of the cell stack 18 in the stacking direction.

As shown in FIG. 2 , the power generating cell 16 has an MEA 26 with a resin frame sandwiched between a first separator 28 and a second separator 30 . The first separator 28 and the second separator 30 are, for example, a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, or a thin metal plate whose metal surface is subjected to anti-corrosion surface treatment, and are press-formed into a corrugated cross section. be done. The first separator 28 and the second separator 30 adjacent to each other are integrally joined together by welding, brazing, caulking, or the like to form a joint separator 31 .

The resin-framed MEA 26 includes an electrolyte membrane-electrode assembly (hereinafter referred to as "MEA 26a"), and a resin frame member 32 (resin frame, resin film) that is joined to and surrounds the outer periphery of the MEA 26a. Prepare. The MEA 26 a has an electrolyte membrane 34 , an anode electrode 36 provided on one side of the electrolyte membrane 34 , and a cathode electrode 38 provided on the other side of the electrolyte membrane 34 .

The electrolyte membrane 34 is, for example, a solid polymer electrolyte membrane (cation exchange membrane). The solid polymer electrolyte membrane is, for example, a thin film of perfluorosulfonic acid containing water. An electrolyte membrane 34 is sandwiched between an anode electrode 36 and a cathode electrode 38 . The electrolyte membrane 34 can use an HC (hydrocarbon)-based electrolyte in addition to the fluorine-based electrolyte.

Although not shown in detail, the anode electrode 36 has a first electrode catalyst layer bonded to one surface of the electrolyte membrane 34 and a first gas diffusion layer laminated on the first electrode catalyst layer. The cathode electrode 38 has a second electrode catalyst layer bonded to the other surface of the electrolyte membrane 34 and a second gas diffusion layer laminated on the second electrode catalyst layer. The resin frame member 32 is provided on the outer peripheral side of the power generation surface 40 of the MEA 26a.

The MEA 26 with a resin frame may be formed without using the resin frame member 32 so that the electrolyte membrane 34 protrudes outward. Alternatively, the MEA 26 with a resin frame may be formed so that frame-shaped films are provided on both sides of the electrolyte membrane 34 projecting outward.

An oxidant gas supply passage 42a, two cooling medium discharge passages 44b, and two fuel gas discharge passages 46b are provided at one edge in the long side direction of the power generation cell 16 (the edge in the arrow B1 direction). . The oxidant gas supply passage 42a, the two cooling medium discharge passages 44b, and the two fuel gas discharge passages 46b each penetrate the cell stack 18 in the stacking direction. The oxidant gas supply passage 42a, the two cooling medium discharge passages 44b, and the two fuel gas discharge passages 46b are arranged vertically (along the short side of the rectangular power generating cell 16).

The oxidant gas supply communication hole 42a is arranged between two cooling medium discharge communication holes 44b which are spaced apart in the vertical direction. The fuel gas discharge communication hole 46b has a first fuel gas discharge communication hole 46b1 and a second fuel gas discharge communication hole 46b2. The first fuel gas discharge communication hole 46b1 is arranged above the upper cooling medium discharge communication hole 44b. The second fuel gas discharge passage 46b2 is arranged below the lower cooling medium discharge passage 44b.

A fuel gas supply communication hole 46a, two cooling medium supply communication holes 44a, and two oxidant gas discharge communication holes 42b are provided at the other end edge (the edge in the arrow B2 direction) of the power generating cell 16 in the long side direction. be done.

The fuel gas supply passage 46a, the two cooling medium supply passages 44a, and the two oxidant gas discharge passages 42b each penetrate the cell stack 18 in the stacking direction. The fuel gas supply passage 46a, the two cooling medium supply passages 44a, and the two oxidant gas discharge passages 42b are arranged in the vertical direction (direction along the short side of the rectangular power generation cell 16). .

The fuel gas supply communication hole 46a is arranged between two cooling medium supply communication holes 44a which are spaced apart in the vertical direction. The oxidant gas discharge communication hole 42b has a first oxidant gas discharge communication hole 42b1 and a second oxidant gas discharge communication hole 42b2. The first oxidizing gas discharge communication hole 42b1 is arranged above the cooling medium supply communication hole 44a on the upper side. The second oxygen-containing gas discharge communication hole 42b2 is arranged below the cooling medium supply communication hole 44a on the lower side.

The fuel gas supply communication hole 46a supplies fuel gas, which is one of the reaction gases. As the fuel gas, for example, a hydrogen-containing gas or the like is used. The oxidant gas supply communication hole 42a supplies the oxidant gas, which is the other reaction gas. As the oxidant gas, for example, an oxygen-containing gas or the like is used.

The fuel gas discharge communication hole 46b discharges the fuel exhaust gas, which is one reaction exhaust gas. The oxidant gas discharge communication hole 42b discharges the other reaction waste gas, ie, the oxidant waste gas. The cooling medium supply communication hole 44a supplies the cooling medium. Pure water, ethylene glycol, oil, or the like is used as the cooling medium. The cooling medium discharge communication hole 44b discharges the cooling medium.

The arrangement, shape and size of the oxidizing gas supply passage 42a, the oxidizing gas discharge passage 42b, the fuel gas supply passage 46a and the fuel gas discharge passage 46b are not limited to those of this embodiment, and may be changed according to requirements. It may be appropriately set according to the specifications to be used.

A surface 28 a of the first separator 28 facing the resin-framed MEA 26 is provided with a fuel gas flow path 48 (reaction gas flow path) through which the fuel gas flows along the power generation surface 40 in the arrow B direction (horizontal direction). The fuel gas channel 48 fluidly communicates with the fuel gas supply communication hole 46a and the two fuel gas discharge communication holes 46b. A surface 28a of the first separator 28 is provided with a first sealing portion 50 for preventing leakage of fluids (fuel gas, oxidant gas, and cooling medium).

On the surface 30a of the second separator 30 facing the resin-framed MEA 26, an oxidant gas channel 52 (reactant gas channel) for circulating the oxidant gas in the direction of arrow B (horizontal direction) along the power generation surface 40 is provided. be done. The oxidant gas channel 52 fluidly communicates with the oxidant gas supply communication hole 42a and the two oxidant gas discharge communication holes 42b. A surface 30a of the second separator 30 is provided with a second seal portion 54 that prevents fluid (fuel gas, oxidant gas, and cooling medium) from leaking.

Between the back surface 28b of the first separator 28 and the back surface 30b of the second separator 30, which are joined together, there is a cooling medium flow fluidly communicating with the cooling medium supply passage 44a and the two cooling medium discharge passages 44b. A path 56 is formed. The cooling medium channel 56 is formed by overlapping the back surface shape of the first separator 28 in which the fuel gas channel 48 is formed and the back surface shape of the second separator 30 in which the oxidant gas channel 52 is formed.

As shown in FIG. 3, the first fuel gas discharge communication hole 46b1 and the second fuel gas discharge communication hole 46b2 are connected to the first connecting flow path 60 at the end opposite to the end plate 24b (back side end). are connected to each other by The first connection flow path 60 has an end portion of the first fuel gas discharge passage 46b1 opposite to the direction of flow of the fuel exhaust gas and an end portion of the second fuel gas discharge passage 46b2 opposite to the direction of flow of the fuel exhaust gas. connect the parts to each other. The first connection channel 60 extends vertically within the insulator 22a.

The first connecting channel 60 communicates with a drain 64 via a second connecting channel 62 . The drain 64 is a flow path for discharging water remaining in the fuel gas discharge communication hole 46b. The drain 64 is positioned below the second fuel gas discharge communication hole 46b2. The drain 64 penetrates the cell stack 18 in the stacking direction.

The first connecting channel 60 and the second connecting channel 62 may be provided in the terminal plate 20a (see FIG. 1) or the end plate 24a. Also, the first connection channel 60 and the second connection channel 62 may be provided in a connection channel member arranged outside the end plate 24a.

As shown in FIG. 2, the fuel cell stack 12 is provided with a drain 66 for discharging water remaining in the oxidizing gas discharge passage 42b. Drain 66 is formed similarly to drain 64 described above.

As shown in FIG. 1 , the fuel gas supply device 14 has a fuel gas supply passage 70 that guides fuel gas in a fuel gas tank (not shown) to the fuel gas supply communication hole 46 a of the fuel cell stack 12 . An injector device 72 and an ejector 74 are arranged in series in the fuel gas supply path 70 . The injector device 72 has a fuel injection valve (not shown) capable of adjusting the flow rate of the fuel gas flowing through the fuel gas supply passage 70 . The injector device 72 may have a plurality of fuel injection valves arranged parallel to each other.

The ejector 74 uses the fuel gas guided from the injector device 72 to suck the fuel exhaust gas guided from a circulation flow path 82 described later, mixes it with the fuel gas, and discharges it downstream.

As shown in FIG. 3, the fuel cell system 10A further includes a first gas lead-out path 76, a second gas lead-out path 78, a gas-liquid separation device 80, a circulation channel 82 and a drainage mechanism 84.

The first gas lead-out path 76 communicates with the first fuel gas discharge communication hole 46b1 to discharge the fuel exhaust gas flowing through the first fuel gas discharge communication hole 46b1. The first gas lead-out path 76 includes a first lead-out hole 86 and a first connection channel 88 . The first lead-out hole 86 penetrates the insulator 22b and the end plate 24b in the stacking direction. The first lead-out hole 86 is adjacent to the first fuel gas discharge communication hole 46b1. The first connection channel 88 is formed by a pipe that connects the end plate 24b and the gas-liquid separation device 80 to each other. The first connection channel 88 guides the fuel exhaust gas led from the first lead-out hole 86 to the gas-liquid separation device 80 .

The second gas lead-out path 78 communicates with the second fuel gas discharge communication hole 46b2 to discharge the fuel exhaust gas flowing through the second fuel gas discharge communication hole 46b2. The second gas lead-out path 78 includes a second lead-out hole 90 and a second connection channel 92 . The second lead-out hole 90 penetrates the insulator 22b and the end plate 24b in the stacking direction. The second lead-out hole 90 is adjacent to the second fuel gas discharge communication hole 46b2. The second connection channel 92 is formed by a pipe that connects the end plate 24b and the gas-liquid separation device 80 to each other. The second connection channel 92 guides the fuel exhaust gas led from the second lead-out hole 90 to the gas-liquid separation device 80 .

The gas-liquid separation device 80 includes a gas-liquid separation section 94 (gas-liquid separation main body) and a water storage section 96 . The first connection channel 88 and the second connection channel 92 are connected to the gas-liquid separation section 94 . The gas-liquid separation section 94 separates the fuel exhaust gas guided from the first connection channel 88 and the second connection channel 92 into gas-liquid. Liquid water separated from the fuel exhaust gas by the gas-liquid separator 94 is stored in the water reservoir 96 . The circulation flow path 82 guides the fuel exhaust gas separated by the gas-liquid separator 94 to the ejector 74 (see FIG. 1).

The drainage mechanism 84 has a water lead-out path 100, a drainage path 102, a drainage valve 104, a first reduced flow path section 106 and a second reduced flow path section . The water lead-out path 100 communicates with the drain 64 to discharge water remaining in the drain 64 . The water lead-out path 100 includes a water lead-out hole 110 and a connecting channel 112 . The water lead-out hole 110 penetrates the insulator 22b and the end plate 24b in the stacking direction. Water outlet hole 110 is adjacent to drain 64 . The connection channel 112 is formed by a pipe that connects the end plate 24b and the gas-liquid separation device 80 to each other. The connection channel 112 guides the retained water led from the water lead-out hole 110 to the water reservoir 96 of the gas-liquid separator 80 .

Drain 102 is connected to the bottom of reservoir 96 . The drainage channel 102 discharges liquid water including the retained water stored in the water storage section 96 to the outside. A drain valve 104 is provided in the drain channel 102 . The drain valve 104 is an on-off valve that opens and closes the drain path 102 .

The first reduced flow path portion 106 is provided in the first connection flow path 88 of the first gas lead-out path 76 . The first reduced flow path portion 106 has a first narrowed portion 114 that is a portion of the first connecting flow path 88 with a reduced diameter. The channel cross-sectional area of the first narrowed portion 114 is smaller than the channel cross-sectional area of the first fuel gas discharge communication hole 46b1.

The first reduced flow path portion 106 may be provided in the first lead-out hole 86 instead of the first connection flow path 88 . That is, the first reduced flow path portion 106 may be provided in the insulator 22b or the end plate 24b. The first contracted flow path portion 106 is formed by forming the first connection flow path 88 with a pipe having a flow path cross-sectional area smaller than that of the first fuel gas discharge communication hole 46b1. 76 may be provided.

The second reduced flow path portion 108 is provided in the second connection flow path 92 of the second gas lead-out path 78 . The second reduced flow path portion 108 has a second constricted portion 116 in which a portion of the second connection flow path 92 is reduced in diameter. The channel cross-sectional area of the second narrowed portion 116 is smaller than the channel cross-sectional area of the second fuel gas discharge communication hole 46b2.

The second reduced channel portion 108 may be provided in the second lead-out hole 90 instead of the second connection channel 92 . That is, the second reduced flow path portion 108 may be provided in the insulator 22b or the end plate 24b. The second reduced flow path portion 108 is formed by forming the second connection flow path 92 with a pipe having a flow path cross-sectional area smaller than that of the second fuel gas discharge communication hole 46b2. 78 may be provided.

Next, the operation of the fuel cell system 10A will be explained.

In FIG. 1 , fuel gas is supplied from a fuel gas tank (not shown) to a fuel gas supply passage 70 and supplied to the fuel gas supply communication hole 46 a of the fuel cell stack 12 via an injector device 72 and an ejector 74 . In FIG. 2, the fuel gas supplied to the fuel gas supply communication hole 46a is introduced into the fuel gas flow path 48 of each power generation cell 16, flows along the power generation surface 40, and is supplied to the anode electrode 36.

On the other hand, the oxidant gas is supplied to the oxidant gas supply communication hole 42a of the fuel cell stack 12 from an oxidant gas supply device (not shown). The oxidant gas supplied to the oxidant gas supply communication hole 42 a is introduced into the oxidant gas flow path 52 of each power generation cell 16 and supplied to the cathode electrode 38 by flowing along the power generation surface 40 .

Therefore, in each MEA 26a, the fuel gas supplied to the anode electrode 36 and the oxygen contained in the oxidant gas supplied to the cathode electrode 38 are consumed by an electrochemical reaction within the electrode catalyst layer to generate power. At this time, water is generated at the cathode electrode 38 . This generated water permeates the electrolyte membrane 34 and reaches the anode electrode 36 .

Also, the cooling medium is supplied to the cooling medium supply communication hole 44 a of the fuel cell stack 12 from a cooling medium supply device (not shown). The cooling medium flows along the cooling medium flow paths 56, cools the power generation cells 16, and is then discharged to the cooling medium discharge communication holes 44b.

The oxidant gas supplied to the cathode electrode 38 and partly consumed is discharged together with the generated water as oxidant exhaust gas (reaction exhaust gas) through the oxidant gas discharge passage 42b (the first oxidant gas discharge passage 42b1 and the second oxidant gas discharge passage 42b1). It is discharged to the agent gas discharge communication hole 42b2).

The fuel gas supplied to the anode electrode 36 and partially consumed is discharged together with the generated water as fuel exhaust gas (reaction exhaust gas) through the fuel gas discharge passage 46b (the first fuel gas discharge passage 46b1 and the second fuel gas discharge passage 46b1). 46b2).

In FIG. 1, the fuel exhaust gas led to the first fuel gas discharge communication hole 46b1 is led to the gas-liquid separator 94 via the first gas lead-out path 76. As shown in FIG. The fuel exhaust gas (reaction exhaust gas) guided to the second fuel gas discharge communication hole 46b2 is guided to the gas-liquid separator 94 via the second gas lead-out path 78. As shown in FIG. The fuel exhaust gas guided to the gas-liquid separation section 94 is returned to the fuel gas supply path 70 by the venturi effect of the ejector 74 through the circulation path 82 after moisture is removed by the gas-liquid separation. The liquid water separated by the gas-liquid separation section 94 is stored in the water storage section 96 .

As shown in FIG. 3, in such a fuel cell stack 12, water generated during power generation and condensed water exist as stagnant water in the fuel gas discharge passage 46b. For example, when the fuel cell system 10A is installed in a fuel cell electric vehicle (not shown), one end (end plate 24a side) of the fuel cell stack 12 is positioned lower than the other end (end plate 24b side). may be inclined to

As a result, water remaining in the first fuel gas discharge communication hole 46b1 is led to the drain 64 via the first connection flow path 60 and the second connection flow path 62. As shown in FIG. Also, water remaining in the second fuel gas discharge communication hole 46 b 2 is guided to the drain 64 via the second connection flow path 62 . In this case, since the water lead-out path 100 is positioned above the drain 64, it is difficult to discharge water remaining in the drain 64.

However, in the present embodiment, since the flow of the fuel exhaust gas to the gas-liquid separation section 94 is throttled by the first reduced flow path section 106 and the second reduced flow path section 108, the pressure in the fuel gas discharge communication hole 46b becomes relatively high. Therefore, even when the amount of fuel gas supplied to the fuel cell stack 12 is relatively small when the fuel cell stack 12 is tilted as shown in FIG. is smoothly flushed to the water reservoir 96 through the water lead-out passage 100 .

At this time, as shown in FIG. 4, when the drain valve 104 opens the drain passage 102 (the drain valve 104 is opened), the pressure in the water reservoir 96 decreases, so that the accumulated water in the drain 64 is stored. It is more smoothly guided to the portion 96 . Liquid water (including stagnant water) in the water reservoir 96 is discharged to the drainage channel 102 . As a result, it is possible to prevent the fuel cell stack 12 from being damaged due to the accumulated water blocking the fuel gas discharge passage 46b, which may cause the power generation performance to deteriorate, and the accumulated water to freeze in the fuel gas discharge passage 46b. effectively suppressed.

In this case, the fuel cell system 10A according to this embodiment has the following effects.

In the fuel cell system 10A, a first fuel gas discharge communication hole 46b1, a second fuel gas discharge communication hole 46b2, and a drain 64 are formed through the cell stack 18 along the stacking direction of the power generating cells 16. As shown in FIG. Further, in the fuel cell stack 12, a first gas lead-out passage 76 communicates with the first fuel gas discharge communication hole 46b1 to discharge the fuel exhaust gas, and a second fuel gas discharge communication hole 46b2 communicates with the fuel exhaust gas to lead out the fuel exhaust gas. A second gas lead-out path 78 is provided. The first gas lead-out path 76 is provided with a first reduced flow path portion 106 having a flow path cross-sectional area smaller than that of the first fuel gas discharge communication hole 46b1. , a second reduced flow path portion 108 having a flow path cross-sectional area smaller than the flow path cross-sectional area of the second fuel gas discharge communication hole 46b2.

According to such a configuration, the pressure of the fuel exhaust gas in the fuel gas discharge communication hole 46b can be increased by the first contraction flow path portion 106 and the second contraction flow channel portion 108, so that the accumulated water in the drain 64 can be reduced. It can be pushed out by the fuel exhaust gas in the fuel gas discharge communication hole 46b. As a result, the water remaining in the drain 64 can be smoothly discharged with a simple configuration.

The first narrowed passage portion 106 has a first constricted portion 114 that is a portion of the first gas lead-out passage 76 with a reduced diameter, and the second narrowed passage portion 108 has a It has a second narrowed portion 116 with a reduced diameter.

With such a configuration, the flow of the fuel exhaust gas discharged from the fuel cell stack 12 can be throttled with a simple configuration.

The fuel cell system 10A includes a gas-liquid separation section 94 for gas-liquid separation of the fuel exhaust gas guided from the first gas lead-out path 76 and the second gas lead-out path 78, and the liquid water separated by the gas-liquid separation section 94 is stored. a water storage portion 96 that separates fuel gas from the gas-liquid separation portion 94; a circulation passage 82 for circulating the fuel exhaust gas separated by the gas-liquid separation portion 94 to the fuel cell stack 12; 100 , a drainage channel 102 for discharging liquid water and stagnant water stored in the water storage part 96 , and a drainage valve 104 for opening and closing the drainage channel 102 .

According to such a configuration, the liquid water separated from the gas and liquid from the fuel exhaust gas and the remaining water remaining in the fuel gas discharge communication hole 46b can be discharged together. Further, by opening the drain passage 102 with the drain valve 104, the pressure in the water storage portion 96 can be reduced, so that the accumulated water in the drain 64 can be drained more smoothly.

This embodiment is not limited to the configuration described above. The number of fuel gas discharge communication holes 46b may be three or more. In this case, the number of gas lead-out paths (first gas lead-out path 76, etc.) and reduced flow path portions (first reduced flow path portion 106, etc.) is provided in a number corresponding to the number of fuel gas discharge communication holes 46b.

(Second embodiment)
Next, a fuel cell system 10B according to a second embodiment of the invention will be described. In the fuel cell system 10B, the same reference numerals are given to the same components as in the above-described fuel cell system 10A, and the description thereof will be omitted.

As shown in FIG. 5, in the fuel cell system 10B, the gas-liquid separator 80 is directly connected to the end plate 24b. Therefore, the fuel cell system 10B has a first gas lead-out path 76a made up of the first lead-out hole 86 and a second gas lead-out path 78a made up of the second lead-out hole 90. As shown in FIG. Further, the fuel cell system 10B includes a drainage mechanism 120 instead of the drainage mechanism 84 described above.

The drain mechanism 120 has a drain channel 122 , a drain valve 104 , a water lead-out channel 124 , a first contracted channel portion 126 and a second contracted channel portion 128 .

Drainage channel 122 includes a first drainage channel 130 provided in water storage portion 96 of gas-liquid separation device 80 and a second drainage channel 132 extending from the bottom of water storage portion 96 . Specifically, the first drainage channel 130 is formed by a wall portion that constitutes the water storage portion 96 . However, the first drainage channel 130 may be formed by piping provided inside the water storage section 96 . The second drainage channel 132 discharges the water stored in the water reservoir 96 to the outside. The drain valve 104 is provided in the second drain channel 132 . The drain valve 104 is an on-off valve that opens and closes the second drain passage 132 .

The water lead-out channel 124 includes a water lead-out hole 110 and a connection channel 134 that guides the retained water led from the water lead-out hole 110 to the first drain channel 130 . The connection channel 134 is provided within the water reservoir 96 . Specifically, the connection channel 134 is formed by a tubular member provided inside the water reservoir 96 . However, the connection channel 134 may be formed by a wall portion that constitutes the water reservoir 96 . The connection channel 134 merges with the drainage channel 122 upstream of the drainage valve 104 (first drainage channel 130 ).

The first reduced channel portion 126 is provided in the first drainage channel 130 . The first contracted flow path portion 126 allows the accumulated water in the drain 64 to flow through the water lead-out path 124 when the second drain path 132 is opened by the drain valve 104 (when the drain valve 104 is opened). 1 to generate a differential pressure that is directed to drain 130 . The first reduced flow channel portion 126 has a first narrowed portion 136 that is a portion of the first drainage channel 130 with a reduced diameter. The channel cross-sectional area of the first narrowed portion 136 is smaller than the channel cross-sectional area of the first fuel gas discharge communication hole 46b1 (or the second fuel gas discharge communication hole 46b2).

The first reduced flow path portion 126 forms the first drainage path 130 with piping having a flow path cross-sectional area smaller than that of the first fuel gas discharge communication hole 46b1 (second fuel gas discharge communication hole 46b2). It may be configured by

The second reduced channel portion 128 is provided in the connecting channel 134 . The second reduced flow path portion 128 has a second narrowed portion 138 in which a portion of the connection flow path 134 is reduced in diameter. The channel cross-sectional area of the second narrowed portion 138 is smaller than the channel cross-sectional area of the drain 64 .

The second reduced flow path portion 128 may be configured by forming the connection flow path 134 with a pipe having a flow path cross-sectional area smaller than that of the drain 64 .

The flow path diameter S1 of the first narrowed portion 136 (first reduced flow path portion 126), the flow path diameter S2 of the second throttled portion 138 (second reduced flow path portion 128), and the flow path diameter Sa of the drain valve 104 (drain valve 104 when the valve is open) is preferably set to satisfy Sa>(S1+S2) so that the flow of fluid is not restricted by the drain valve 104. FIG. However, the sizes of S1, S2 and Sa can be set appropriately.

In such a fuel cell system 10B, as shown in FIG. Since the pressure on the downstream side of the 2-reduced passage portion 128 decreases, the pressure of the fuel exhaust gas in the fuel gas discharge communication hole 46b becomes relatively high (differential pressure occurs). Due to this differential pressure, water remaining in the drain 64 is discharged to the drainage channel 122 through the water lead-out channel 124 .

In this embodiment, the fuel cell system 10B includes a drainage path 122 for discharging the liquid water separated by the gas-liquid separation unit 94, a drainage valve 104, and a drainage path 122 for discharging accumulated water in the drain 64. and a water lead-out passage 124 leading to the upstream side of the valve 104 . In the drainage path 122, when the drainage path 122 is opened by the drainage valve 104, a first contraction valve that generates a differential pressure such that the water remaining in the drain 64 is led to the drainage path 122 through the water lead-out path 124. A channel portion 126 is provided.

According to such a configuration, when the drain passage 122 is opened by the drain valve 104, a differential pressure is generated by the first reduced flow passage portion 126, so that the accumulated water in the drain 64 can be guided to the drain passage 122. can be done. Therefore, the water remaining in the drain 64 can be smoothly discharged with a simple structure. Further, as shown in FIG. 5, in a state in which the drain passage 122 is closed by the drain valve 104 (a state in which the drain valve 104 is closed), the fuel exhaust gas discharged from the fuel gas discharge communication hole 46b to the gas-liquid separator 94 is , does not pass through the first reduced channel portion 126 . Therefore, the fuel exhaust gas can be efficiently circulated to the fuel cell stack 12 .

The first reduced channel portion 126 is provided upstream of the confluence portion with the water lead-out channel 124 in the drainage channel 122 . According to such a configuration, when the drain valve 104 is opened, water remaining in the drain 64 can be more smoothly discharged to the drain passage 122 .

The water lead-out path 124 is provided with a second reduced flow path portion 128 having a flow path cross-sectional area smaller than that of the drain 64 .

With such a configuration, it is possible to suppress the flow rate of the fuel exhaust gas discharged together with the water remaining in the drain 64 when the drain valve 104 is opened.

The first reduced channel portion 126 has a first narrowed portion 136 that is a portion of the first drainage channel 130 with a reduced diameter, and the second reduced channel portion 128 is a portion of the water lead-out channel 124 that has a reduced diameter. It has a second narrowed portion 138 .

According to such a configuration, the first reduced flow path portion 126 and the second reduced flow path portion 128 can be configured simply.

The channel diameter S1 of the first reduced channel portion 126, the channel diameter S2 of the second reduced channel portion 128, and the channel diameter Sa of the drain valve 104 are set so that Sa>(S1+S2).

With such a configuration, the flow rate of the fluid flowing through the drain valve 104 does not limit the flow rate of the fluid flowing through the first contracted flow path portion 126 and the second contracted flow channel portion 128, respectively. can be discharged more smoothly.

In this embodiment, the second reduced flow path portion 128 may be omitted. Even in this case, water remaining in the drain 64 can be smoothly discharged to the drainage channel 122 .

(Third embodiment)
Next, a fuel cell system 10C according to a third embodiment of the invention will be described. In the fuel cell system 10C, the same components as those of the fuel cell system 10B according to the above-described second embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 7, the fuel cell system 10C is provided with a drainage mechanism 140 instead of the drainage mechanism 120. As shown in FIG. The drainage mechanism 140 includes a reduced flow path portion 142 instead of the first reduced flow path portion 126 . It should be noted that the drainage mechanism 140 does not have the above-described second contraction flow path section 128 . The reduced channel portion 142 is provided downstream of the confluence portion of the connection channel 134 in the first drainage channel 130 . The reduced channel portion 142 has a constricted portion 144 in which a portion of the first drainage channel 130 is reduced in diameter. The channel cross-sectional area of the constricted portion 144 is smaller than the channel cross-sectional area of the first fuel gas discharge communication hole 46b1 (or the second fuel gas discharge communication hole 46b2).

The reduced flow path portion 142 functions as an ejector that guides the water remaining in the drain 64 to the first drainage path 130 by the venturi effect. That is, the connecting channel 134 merges in the vicinity of the upstream side of the reduced channel portion 142 in the first drainage channel 130 .

In such a fuel cell system 10C, as shown in FIG. 8, when the drain valve 104 is opened, the fuel exhaust gas is discharged from the gas-liquid separator 94 to the drain passage 122. As shown in FIG. At this time, since the flow velocity of the fuel exhaust gas flowing through the narrowed portion 144 increases, a low pressure is generated on the upstream side of the narrowed portion 144, and the accumulated water in the drain 64 flows into the first drainage passage 130 through the water lead-out passage 124. be sucked. Therefore, water remaining in the drain 64 is smoothly discharged.

In the present embodiment, the reduced flow path portion 142 functions as an ejector that guides water remaining in the drain 64 to the drainage path 122 by the venturi effect.

According to such a configuration, it is possible to smoothly discharge water remaining in the drain 64 with a simple configuration. Further, the fuel exhaust gas discharged from the fuel gas discharge communication hole 46b to the gas-liquid separation section 94 does not pass through the reduced flow path section 142 in a state where the drainage path 122 is blocked by the drainage valve 104 . Therefore, the fuel exhaust gas can be efficiently circulated to the fuel cell stack 12 .

The present invention is not limited to the embodiments described above, and various modifications are possible without departing from the gist of the present invention.

In the fuel cell systems 10B and 10C, the number of the fuel gas discharge communication holes 46b and the number of the oxidant gas discharge communication holes 42b may be one or three or more. The fuel cell systems 10A-10C may include a drain mechanism for draining water remaining in the oxidant gas discharge passage 42b. In this case, the drainage mechanism can be configured in the same manner as the drainage mechanisms 84, 120, 140 described above.

The above embodiment can be summarized as follows.

The above-described embodiment is a fuel having a cell stack (18) in which a plurality of power generation cells (16) are stacked, each having reaction gas flow paths (48, 52) for flowing a reaction gas along the power generation surface (40). A battery stack (12) is provided, and the cell stack includes discharge communication holes (42b, 46b) for discharging the reaction exhaust gas guided from the reaction gas flow path, and the discharge communication holes communicating with the discharge communication holes. A fuel cell system (10A to 10C) in which drains (64, 66) for discharging stagnant water in the discharge communication hole are formed through the power generation cells along the stacking direction, wherein the discharge communication hole are provided in plurality, and the fuel cell stack is provided with a plurality of gas lead-out passages (76, 78) communicating with the plurality of discharge communication holes to lead out the reaction exhaust gas, and the plurality of gas lead-out passages Disclosed is a fuel cell system, each of which is provided with a reduced flow path section (106, 108) having a flow path cross-sectional area smaller than the flow path cross-sectional area of the plurality of discharge communication holes.

In the above-described fuel cell system, the reduced flow path portion may have narrowed portions (114, 116) in which a portion of each of the plurality of gas lead-out paths is reduced in diameter.

In the above fuel cell system, a gas-liquid separation section (94) for gas-liquid separation of the reaction exhaust gas led from the plurality of gas lead-out passages, and a water storage section for storing the liquid water separated by the gas-liquid separation section. (96), a circulation passage (82) for circulating the reaction exhaust gas separated by the gas-liquid separation section to the fuel cell stack, and water for guiding the retained water guided from the drain to the water storage section. An outlet channel (100), a drainage channel (102) for discharging the liquid water and the stagnant water stored in the water reservoir, and a drain valve (104) for opening and closing the drainage channel. may

The above-described embodiment includes a fuel cell stack having a cell stack in which a plurality of power generation cells are stacked, each having a reaction gas flow path for flowing a reaction gas along a power generation surface. A discharge communication hole for discharging the reaction exhaust gas guided from the gas channel, and a drain communicating with the discharge communication hole for discharging the accumulated water are formed through the power generating cells along the stacking direction. The fuel cell system comprises a gas-liquid separation section for gas-liquid separation of the reaction exhaust gas led from the discharge communication hole, and a drainage channel (122) for discharging the liquid water separated by the gas-liquid separation section. ), a drain valve for opening and closing the drain channel, and a water lead-out channel (124) for guiding the accumulated water in the drain to the upstream side of the drain valve in the drain channel, In the drainage channel, when the drainage channel is opened by the drainage valve, a contraction flow that generates a differential pressure such that the stagnant water in the drain is led to the drainage channel through the water lead-out channel. A fuel cell system is disclosed in which channels (126, 142) are provided.

In the fuel cell system described above, the narrowed channel portion may be provided upstream of a confluence portion with the water lead-out channel in the drain channel.

In the above fuel cell system, the reduced flow path portion is a first reduced flow path portion (126), and the water lead-out path has a flow path cross-sectional area smaller than that of the drain. Two reduced channel sections (128) may be provided.

In the fuel cell system described above, the first reduced flow path portion has a first narrowed portion (136) formed by reducing the diameter of a portion of the drainage channel, and the second reduced flow path portion has the water lead-out path. It may have a second constricted portion (138) that is a portion of the diameter of which is reduced.

In the above fuel cell system, the channel diameter S1 of the first reduced channel portion, the channel diameter S2 of the second reduced channel portion, and the channel diameter Sa of the drain valve satisfy Sa>(S1+S2). may be set as

In the fuel cell system described above, the reduced flow path portion (142) may function as an ejector that guides the water remaining in the drain to the drainage path by a venturi effect.

DESCRIPTION OF SYMBOLS 10A-10C... Fuel cell system 12... Fuel cell stack 16... Power generation cell 18... Cell stack 40... Power generation surface 42b... Oxidant gas discharge communication hole (discharge communication hole)
46b...Fuel gas discharge communication hole (discharge communication hole)
48... Fuel gas channel (reactant gas channel) 52... Oxidant gas channel (reactant gas channel)
64, 66... Drain 76... First gas lead-out path (gas lead-out path)
78 Second gas lead-out path (gas lead-out path) 82 Circulation flow path 94 Gas-liquid separator 96 Water reservoirs 100, 124 Water lead-out path 102 Drainage path 104 Drainage valves 106, 126 First contraction flow Path (reduced flow path)
108, 128 . . . second reduced flow path portion (reduced flow path portion)
114, 136... 1st diaphragm part (diaphragm part) 116, 138... 2nd diaphragm part (diaphragm part)
142... Reduced flow path part

Claims (11)

A fuel cell stack having a cell stack in which a plurality of power generation cells are stacked, each having a reaction gas flow path for flowing a reaction gas along a power generation surface. A discharge communication hole for discharging the reacted exhaust gas, and a drain communicating with the discharge communication hole for discharging the accumulated water in the discharge communication hole are formed through the power generation cells along the stacking direction. a fuel cell system comprising:
Insulators and end plates are sequentially arranged outward in the stacking direction at both ends of the cell stack in the stacking direction,
A plurality of the discharge communication holes are provided,
The fuel cell stack is provided with a plurality of gas lead-out paths communicating with the plurality of discharge communication holes to lead out the reaction exhaust gas,
Each of the plurality of gas lead-out passages is provided with a reduced flow passage portion having a flow passage cross-sectional area smaller than that of the plurality of discharge communication holes,
the reduced flow path portion is provided in the insulator or the end plate of the fuel cell stack,
The fuel cell system according to claim 1, wherein the reactive exhaust gas in the plurality of discharge communication holes, the pressure of which is increased by the contracted passage portion, pushes out the water remaining in the drain. A fuel cell stack having a cell stack in which a plurality of power generation cells are stacked, each having a reaction gas flow path for flowing a reaction gas along a power generation surface. A discharge communication hole for discharging the reacted exhaust gas, and a drain communicating with the discharge communication hole for discharging the accumulated water in the discharge communication hole are formed through the power generation cells along the stacking direction. a fuel cell system comprising:
A plurality of the discharge communication holes are provided,
The fuel cell stack is provided with a plurality of gas lead-out paths communicating with the plurality of discharge communication holes to lead out the reaction exhaust gas,
The fuel cell system has a gas-liquid separation unit for gas-liquid separation of the reaction exhaust gas led from the plurality of gas lead-out paths,
each of the plurality of gas lead-out passages includes a connection passage that connects the end plate of the fuel cell stack and the gas-liquid separator to each other;
The connection channel is provided with a reduced channel portion having a channel cross-sectional area smaller than the channel cross-sectional area of the plurality of discharge communication holes,
The fuel cell system according to claim 1, wherein the reactive exhaust gas in the plurality of discharge communication holes, the pressure of which is increased by the contracted passage portion, pushes out the water remaining in the drain. 3. The fuel cell system according to claim 1 or 2 ,
The fuel cell system according to claim 1, wherein the reduced passage portion has a constricted portion in which a portion of each of the plurality of gas lead-out passages is reduced in diameter. The fuel cell system according to claim 1 ,
a gas-liquid separation unit for gas-liquid separation of the reaction exhaust gas guided from the plurality of gas lead-out paths;
a water storage section for storing liquid water separated by the gas-liquid separation section;
a circulation channel for circulating the reaction exhaust gas separated by the gas-liquid separator to the fuel cell stack;
a water lead-out path leading the stagnant water led from the drain to the water reservoir;
a drainage channel for discharging the liquid water and the stagnant water stored in the water reservoir;
and a drain valve that opens and closes the drain channel. 3. The fuel cell system according to claim 2,
a water storage section for storing liquid water separated by the gas-liquid separation section;
a circulation channel for circulating the reaction exhaust gas separated by the gas-liquid separator to the fuel cell stack;
a water lead-out path leading the stagnant water led from the drain to the water reservoir;
a drainage channel for discharging the liquid water and the stagnant water stored in the water reservoir;
and a drain valve that opens and closes the drain channel. A fuel cell stack having a cell stack in which a plurality of power generation cells are stacked, each having a reaction gas flow path for flowing a reaction gas along a power generation surface. A fuel cell system in which a discharge communication hole for discharging the reacted exhaust gas and a drain communicating with the discharge communication hole for discharging accumulated water are formed through the power generation cells along the stacking direction. hand,
a gas-liquid separation unit for gas-liquid separation of the reaction exhaust gas guided from the discharge communication hole;
a drainage channel for discharging the liquid water separated by the gas-liquid separator;
a drain valve for opening and closing the drain;
a water lead-out path that guides the stagnant water in the drain upstream of the drain valve in the drain path,
In the drainage channel, when the drainage channel is opened by the drainage valve, a contraction flow that generates a differential pressure such that the water remaining in the drain is led to the drainage channel through the water lead-out channel. A fuel cell system provided with a channel. The fuel cell system according to claim 6 ,
The fuel cell system according to claim 1, wherein the narrowed flow path portion is provided upstream of a confluence portion with the water lead-out path in the drainage path. The fuel cell system according to claim 7 ,
The reduced flow path portion is a first reduced flow path portion,
The fuel cell system according to claim 1, wherein the water lead-out path is provided with a second reduced flow path portion having a flow path cross-sectional area smaller than that of the drain. The fuel cell system according to claim 8 ,
The first reduced flow path portion has a first narrowed portion obtained by reducing the diameter of a part of the drainage channel,
The fuel cell system, wherein the second reduced flow path portion has a second constricted portion formed by reducing a diameter of a part of the water lead-out path. The fuel cell system according to claim 8 or 9 ,
The channel diameter S1 of the first reduced channel portion, the channel diameter S2 of the second reduced channel portion, and the channel diameter Sa of the drain valve are set so that Sa>(S1+S2). fuel cell system. The fuel cell system according to claim 8 ,
The fuel cell system, wherein the reduced flow path portion functions as an ejector that guides the stagnant water in the drain to the drainage path by a venturi effect.

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