JP2007141716A - Fuel cell system - Google Patents

Abstract

A simple tightening load can be reliably applied to a fuel cell and a flat membrane humidifier.
A fuel cell system (10) includes an intermediate plate (15) interposed between a fuel cell stack (12) and a humidifier (14), a first connection plate (74a) for holding the fuel cell stack (12), and the humidifier (14). 2nd connection plate 76a which holds. The intermediate plate 15, the first connection plate 74a, and the second connection plate 76a are provided with cylindrical portions 80, 82b, and 84b that are arranged on the same line, and a connection pin 86c is inserted integrally therewith.
[Selection] Figure 2

Description

  The present invention relates to a fuel cell system in which a polymer electrolyte fuel cell and a flat membrane humidifier are stacked in the stacking direction.

  For example, a polymer electrolyte fuel cell has a power generation cell in which an electrolyte membrane / electrode structure in which an anode side electrode and a cathode side electrode are arranged on both sides of an electrolyte membrane made of a polymer ion exchange membrane is sandwiched by separators. I have. This type of fuel cell is normally used as a fuel cell stack by stacking a predetermined number of power generation cells.

  In this fuel cell, a fuel gas, for example, a gas mainly containing hydrogen (hereinafter also referred to as hydrogen-containing gas) is supplied to the anode side electrode, while an oxidant gas, for example, A gas or air mainly containing oxygen (hereinafter also referred to as oxygen-containing gas) is supplied.

  Usually, a fuel cell is used as a fuel cell stack in which a predetermined number (for example, several tens to several hundreds) is stacked in order to obtain a desired power generation. In this fuel cell stack, the stacked fuel cells need to be reliably pressurized and held in order to prevent an increase in the internal resistance of the fuel cell and a decrease in the sealing performance of the reaction gas.

  On the other hand, in the fuel cell described above, it is necessary to maintain the electrolyte membrane in an appropriate wet state in order to exhibit an effective power generation function. For this reason, a humidifier that humidifies fuel gas and oxidant gas in advance through water is prepared, and the humidified fuel gas and oxidant gas are supplied to the fuel cell by connecting the humidifier to the fuel cell. What is supplied is known.

  In this case, as the humidifier, a flat membrane humidifier configured by alternately laminating water permeable membranes and separators is frequently used, and the flat membrane humidifier and the fuel cell are integrally held. A fuel cell integrated flat membrane humidifier structure is adopted. At that time, in the above structure, it is necessary to hold the flat membrane humidifier and the fuel cell integrally with a predetermined tightening load in the stacking direction. For example, the fuel cell stack disclosed in Patent Document 1 is applied. It is possible.

  As shown in FIG. 6, the fuel cell stack includes a stacked body 2 in which a plurality of unit cells 1 are stacked, and auxiliary plates 4 a with end plates 3 and 3 interposed at both ends in the stacking direction of the stacked body 2. 4b are arranged.

  A pair of fastening bands 5 and 5 are disposed along both side portions of the laminate 2. Cylindrical bosses 6 are provided at the ends of the fastening bands 5 and 5 and the auxiliary plates 4a and 4b so that the respective holes are aligned in a straight line. The fastening pins 5 and 5 and the auxiliary plates 4a and 4b are integrally connected by inserting the metal pin 7 into each boss portion 6.

  A plurality of bolts 8 are screwed onto the auxiliary plate 4a, while a plurality of disc springs 9 are disposed on the auxiliary plate 4b. Therefore, when the bolt 8 is screwed in, the end plate 3 is pressed downward, and the disc spring 9 disposed on the auxiliary plate 4b is compressed, which is necessary for the laminated body 2 via the pair of end plates 3. The fastening pressure is applied.

JP 2001-135344 A (FIG. 5)

  However, in Patent Document 1 described above, a plurality of bolts 8 and a plurality of disc springs 9, which are dedicated parts, are provided in order to adjust the tightening load of the fuel cell stack. Therefore, there is a problem in that the weight of the entire fuel cell stack increases due to the addition of dedicated parts.

  Moreover, in the fuel cell integrated flat membrane humidifier structure, a clamping load is applied to the fuel cell and the flat membrane humidifier via the pair of fastening bands 5 and 5. At that time, the tightening load required for the flat membrane humidifier is considerably smaller than the tightening load required for the fuel cell due to a difference in sealing performance. For this reason, when a necessary tightening load is applied to the fuel cell by the pair of fastening bands 5, 5, there is a problem that an unnecessarily large tightening load is applied to the flat membrane humidifier.

  The present invention solves this type of problem, and provides a fuel cell system capable of reliably applying a desired tightening load to a fuel cell and a flat membrane humidifier with a simple configuration. With the goal.

  In the present invention, an electrolyte membrane / electrode structure provided with electrodes on both sides of an electrolyte membrane and a separator are stacked, and a fuel gas and an oxidant gas which are reaction gases are supplied, and a solid to which a cooling medium is supplied A polymer type fuel cell and a flat membrane type humidifier provided with a water permeable membrane for humidifying at least one reaction gas supplied to the solid polymer type fuel cell with a humidified fluid are stacked in the stacking direction. It is a fuel cell system.

  The fuel cell system is arranged with an intermediate plate interposed between the polymer electrolyte fuel cell and the flat membrane humidifier, and extending in the stacking direction with respect to the side of the polymer electrolyte fuel cell. A first connecting plate that holds the polymer electrolyte fuel cell, and a second connecting plate that extends in the stacking direction with respect to the side of the flat membrane humidifier and holds the flat membrane humidifier. And a connecting plate. The intermediate plate, the first connection plate, and the second connection plate are provided with a cylindrical portion that is arranged on the same axis line and is fixed with the connection pins inserted integrally.

  The polymer electrolyte fuel cell is stacked between the intermediate plate and the first end plate, and the flat membrane humidifier is stacked between the intermediate plate and the second end plate. It is preferable that the connecting plate fixes the intermediate plate and the first end plate, while the second connecting plate fixes the intermediate plate and the second end plate.

  In the present invention, the polymer electrolyte fuel cell is held by the intermediate plate and the first connecting plate, and the flat membrane humidifier is held by the intermediate plate and the second connecting plate. For this reason, a desired tightening load can be reliably applied to the polymer electrolyte fuel cell and the flat membrane humidifier.

  Moreover, the cylindrical portions provided on the intermediate plate, the first connecting plate, and the second connecting plate are arranged on the same axis line, and a connecting pin is integrally inserted into the cylindrical portion. Therefore, the number of parts can be reduced well, the structure can be easily simplified, and it is economical.

  FIG. 1 is a schematic configuration explanatory diagram of a fuel cell system 10 according to an embodiment of the present invention, and FIG. 2 is a schematic perspective explanatory diagram of the fuel cell system 10.

  The fuel cell system 10 is mounted on a vehicle such as an automobile, for example, and includes a fuel cell stack 12 and a flat membrane humidifier 14, and the fuel cell stack 12 and the humidifier 14 include an intermediate plate 15. Are stacked together in the stacking direction (arrow A direction).

  The fuel cell stack 12 has a plurality of power generation cells 16 stacked in the direction of arrow A, and a first end plate 18a and an intermediate plate 15 are disposed at both ends in the stacking direction. An intermediate plate 15 and a second end plate 18b are disposed at both ends of the humidifier 14 in the stacking direction.

  As shown in FIG. 1, the power generation cell 16 includes, for example, an electrolyte membrane / electrode structure 20 in which an anode-side electrode 20b and a cathode-side electrode 20c are arranged on both sides of a solid polymer electrolyte membrane 20a, and the electrolyte membrane / electrode. A pair of separators 22 and 24 sandwiching the structure 20 is provided. For example, hydrogen gas is supplied to the anode side electrode 20b as a fuel gas, while air containing oxygen, for example, is supplied to the cathode side electrode 20c as an oxidant gas.

  The fuel cell system 10 includes a hydrogen supply channel 30 for supplying hydrogen gas to the fuel cell stack 12 and an exhaust gas containing unused hydrogen gas discharged from the fuel cell stack 12 into the hydrogen supply channel 30. And a hydrogen circulation flow path 32 for returning to the fuel cell stack 12 and supplying it to the fuel cell stack 12.

  In the hydrogen supply flow path 30, a hydrogen tank 34 that stores high-pressure hydrogen, a regulator 36 that reduces the pressure of the hydrogen gas supplied from the hydrogen tank 34, and the reduced hydrogen gas is supplied to the fuel cell stack 12. In addition, an ejector 38 is provided for sucking exhaust gas from the hydrogen circulation passage 32 and returning it to the fuel cell stack 12.

  A hydrogen supply port 39a for supplying hydrogen gas from the hydrogen supply flow path 30 to the power generation cell 16 and exhaust gas containing unused hydrogen gas discharged from the power generation cell 16 are circulated in the first end plate 18a. A hydrogen discharge port 39b for discharging to the flow path 32 is provided.

  The fuel cell system 10 includes an air supply channel 40 for supplying air to the fuel cell stack 12 and air for exhausting air discharged from the fuel cell stack 12 (hereinafter also referred to as off-gas) to the outside. A discharge channel 42. The air supply channel 40 is provided with a supercharger (or pump) 44 for supplying compressed air.

  As shown in FIGS. 3 and 4, the humidifier 14 is disposed on the first separator 52 disposed on one surface 50 a of the water permeable membrane 50 and on the other surface 50 b of the water permeable membrane 50. The second separator 54 is provided. The first and second separators 52 and 54 are alternately stacked in the direction of arrow A with the water permeable membrane 50 interposed therebetween to form a stacked body 56.

  The first and second separators 52 and 54 are configured by forming a metal plate into a wave shape. The first and second separators 52 and 54 may be configured in a corrugated shape by, for example, machining a carbon plate.

  As shown in FIG. 4, one end edge in the direction of arrow B of the laminate 56 passes through each other in the direction of arrow A and humidifies the air before reaction. The off-gas discharge communication holes 60b for discharging the off-gas after being formed are provided vertically (in the direction of arrow C).

  The other end edge of the laminated body 56 in the direction of arrow B communicates with each other in the direction of arrow A, and an off-gas supply communication hole 60a through which off-gas is supplied and an air discharge communication hole through which humidified air is discharged. 58b are arranged in the vertical direction.

  As shown in FIG. 1, the air supply communication hole 58 a communicates with the air supply flow path 40, and the air discharge communication hole 58 b communicates with an air supply port (not shown) of the fuel cell stack 12. The off gas supply communication hole 60 a communicates with an air discharge port (not shown) of the fuel cell stack 12, and the off gas discharge communication hole 60 b communicates with the air discharge flow path 42.

  As shown in FIG. 4, the first separator 52 communicates the air supply communication hole 58 a and the air discharge communication hole 58 b on the first surface 52 a side facing the one surface 50 a of the water permeable membrane 50. A plurality of serpentine-shaped air flow paths 62 that are halfway back and forth are provided in the direction.

  On the second surface 52b side opposite to the first surface 52a of the first separator 52, an air supply communication hole 58a and an air discharge communication hole 58b are communicated, and a plurality of serpentine shapes of one reciprocal half in the direction of arrow B are provided. An air flow path 64 is provided. The air flow paths 62 are alternately formed with the air flow paths 64 and have a wave shape as a whole (see FIG. 3).

  As shown in FIG. 4, the second separator 54 communicates the off gas supply communication hole 60 a and the off gas discharge communication hole 60 b to the third surface 54 a side facing the other surface 50 b of the water permeable membrane 50, and the direction of the arrow B Are provided with a plurality of serpentine-shaped off-gas passages 66 in one reciprocal half.

  The second separator 54 communicates with the fourth surface 54b opposite to the third surface 54a through the off-gas supply communication hole 60a and the off-gas discharge communication hole 60b, and a plurality of serpentine-shaped serpentine shapes of one and a half reciprocations in the arrow B direction. An off-gas channel 68 is provided. The off gas channel 66 is formed alternately with the off gas channel 68 and has a wave shape as a whole (see FIG. 3).

  A seal 70 is integrally formed on the first separator 52 so as to cover the outer peripheral edge portion, and a seal 72 is integrally formed on the second separator 54 so as to cover the outer peripheral edge portion (see FIG. 4).

  As shown in FIG. 2, first connecting plates 74 a and 74 b are arranged on both upper and lower sides of the fuel cell stack 12 so as to extend in the stacking direction (arrow A direction), and both the upper and lower sides of the humidifier 4. The second connection plates 76a and 76b are arranged extending in the stacking direction.

  A plurality of cylindrical portions 78a each having a predetermined length are provided on each of the upper and lower sides of the first end plate 18a at a predetermined interval. Similarly, a plurality of cylindrical portions 78b are provided at predetermined intervals on the upper and lower sides of the second end plate 18b. A plurality of cylindrical portions 80 are provided on each of the upper and lower sides of the intermediate plate 15 so as to be separated by a predetermined interval.

  A plurality of cylindrical portions 82a disposed between the cylindrical portions 78a of the first end plate 18a are provided on one side of the first connecting plates 74a and 74b on one end side in the horizontal direction. A plurality of cylindrical portions 82b are provided on the sides on the other end side in the horizontal direction of the first connecting plates 74a and 74b so as to be disposed over substantially half the length between the cylindrical portions 80 of the intermediate plate 15.

  A plurality of cylindrical portions 84a disposed between the cylindrical portions 78b of the second end plate 18b are provided on the side of the second connecting plates 76a and 76b on one end side in the horizontal direction. A plurality of cylindrical portions 84b arranged in parallel with the cylindrical portions 82b are provided between the cylindrical portions 80 of the intermediate plate 15 on the other end side in the horizontal direction of the second connecting plate 76a.

  The cylindrical portion 78a provided on both the upper and lower sides of the first end plate 18a and the cylindrical portion 82a provided on the one end side of the first connection plates 74a and 74b are disposed on the same axis, The connecting pin 86a is integrally inserted and fixed.

  The cylindrical portion 78b provided on the upper and lower sides of the second end plate 18b and the cylindrical portion 84a provided on the one end side of the second connection plates 76a and 76b are disposed on the same axis, The connecting pin 86b is integrally inserted and fixed.

  As shown in FIGS. 2 and 5, the cylindrical portion 80 of the intermediate plate 15, the cylindrical portion 82b provided on the other end side of the first connection plates 74a and 74b, and the second connection plates 76a and 76b. The cylindrical portions 84b provided on the end side are arranged on the same axis, and the connecting pin 86c is integrally inserted and fixed.

  In the fuel cell stack 12 and the humidifier 14, spacer members 88 a and 88 b having adjusted thicknesses are provided as necessary in order to absorb a change in the length in the stacking direction and apply a desired tightening load. (See FIG. 2).

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

  As shown in FIG. 1, the hydrogen gas supplied from the hydrogen tank 34 to the hydrogen supply flow path 30 is depressurized to a predetermined pressure via the regulator 36, and then passes through the ejector 38 to supply hydrogen to the fuel cell stack 12. It is supplied to the mouth 39a. After the hydrogen supplied to the hydrogen supply port 39a moves along the anode side electrode 20b constituting each power generation cell 16, exhaust gas containing unused hydrogen is discharged from the hydrogen discharge port 39b to the hydrogen circulation channel 32. Is done. The exhaust gas is returned to the hydrogen supply flow path 30 under the suction action of the ejector 38 and then supplied again as fuel gas into the fuel cell stack 12.

  On the other hand, air is supplied to the air supply channel 40 via the supercharger 44. This air is supplied from the second end plate 18 b constituting the humidifier 14 to the air supply communication hole 58 a of the stacked body 56.

  As shown in FIG. 4, the pre-reaction air supplied to the air supply communication hole 58a moves along a plurality of air flow channels 62, 64 having a serpentine shape. Air flowing through the air flow path 62 contacts one surface 50 a of the water permeable membrane 50, and air moving along the air flow path 64 contacts one surface 50 a of the other water permeable membrane 50. (See FIG. 3).

  In the humidifier 14, off gas, which has been reacted air used for power generation of the fuel cell stack 12, is supplied to the off gas supply communication hole 60a. This off-gas is introduced into off-gas flow paths 66 and 68 communicating with the off-gas supply communication hole 60 a of the second separator 54.

  As shown in FIG. 4, the off-gas moves along a plurality of off-gas passages 66 and 68 having a serpentine shape. For this reason, the off-gas that moves in the off-gas channel 66 contacts the other surface 50 b of the water-permeable membrane 50, and the off-gas that moves along the off-gas channel 68 is the other of the other water-permeable membrane 50. In contact with the surface 50b (see FIG. 3).

  Therefore, the moisture in the off gas that moves along the off gas channel 66 of the second separator 54 is supplied to the pre-reaction air that passes through the water permeable membrane 50 and moves along the air channel 62. Humidified. Further, the air before the reaction that moves along the air flow path 64 is humidified by the off gas that moves along the off gas flow path 68. The humidified air is supplied to the fuel cell stack 12 from the air discharge communication hole 58b.

  As shown in FIG. 1, the humidified air is supplied to the cathode-side electrode 20c of each power generation cell 16, and the off-gas containing unused air is discharged to the humidifier 14 as described above. Thereby, in each power generation cell 16, the hydrogen supplied to the anode side electrode 20b and the oxygen in the air supplied to the cathode side electrode 20c react to generate power.

  In this case, in this embodiment, as shown in FIGS. 1 and 2, the fuel cell stack 12 and the humidifier 14 are integrally stacked in the stacking direction with the intermediate plate 15 interposed therebetween. The fuel cell stack 12 is held via first connection plates 74a and 74b connected to the first end plate 18a and the intermediate plate 15, while the humidifier 14 is connected to the second end plate 18b and the intermediate plate 15b. It is held via second connection plates 76 a and 76 b connected to the plate 15.

  For this reason, it is possible to reliably apply a desired tightening load to the fuel cell stack 12 and the humidifier 14 respectively, and in particular, it is preferable that a larger load than the optimum load is applied to the humidifier 14. It becomes possible to stop. This is because the optimum tightening load is different between the fuel cell stack 12 and the humidifier 14 and the optimum tightening load of the humidifier 14 is smaller than the optimum tightening load of the fuel cell stack 12.

  Moreover, in the present embodiment, as shown in FIGS. 2 and 5, the cylindrical portion 80 of the intermediate plate 15, the cylindrical portion 82b of the first connection plates 74a and 74b, and the cylindrical portion of the second connection plates 76a and 76b. 84b is disposed on the same axis as each other, and a connecting pin 86c is integrally inserted into the cylindrical portions 80, 82b and 84b. Therefore, the connection structure of the fuel cell stack 12 and the connection structure of the humidifier 14 can be used together, and the number of parts can be reduced well, the structure can be easily simplified, and the effect is economical. can get.

  In the present embodiment, the configuration is such that air as one reaction gas is humidified and supplied to the fuel cell stack 12. However, the present invention is not limited to this, and the fuel gas as the other reaction gas is used. A structure for humidifying the air may be employed. Further, although off-gas which is air discharged from the fuel cell stack 12 is used as the humidifying fluid, the present invention is not limited to this, and other humidifying gas, for example, dedicated steam gas, pure water, liquid, or the like is used. It may be used.

1 is an explanatory diagram of a schematic configuration of a fuel cell system according to an embodiment of the present invention. It is a schematic perspective explanatory view of the fuel cell system. It is a partial cross section side view of the humidifier which constitutes the fuel cell system. It is a principal part disassembled perspective explanatory view of the humidifier. It is a principal part disassembled perspective view of the intermediate | middle plate, the 1st connection plate, and the 2nd connection plate which comprise the said fuel cell system. 2 is an explanatory diagram of a fuel cell stack of Patent Document 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fuel cell system 12 ... Fuel cell stack 14 ... Humidifier 15 ... Intermediate plate 16 ... Power generation cell 18a, 18b ... End plate 20 ... Electrolyte membrane and electrode structure 20a ... Solid polymer electrolyte membrane 20b ... Anode side electrode 20c ... Cathode side electrodes 22, 24, 52, 54 ... Separator 40 ... Air supply channel 42 ... Air discharge channel 50 ... Water permeable membrane 56 ... Laminated body 58a ... Air supply communication hole 58b ... Air discharge communication hole 60a ... Off-gas supply Communication hole 60b ... Off gas discharge communication holes 62, 64 ... Air flow channel 66, 68 ... Off gas flow channel 74a, 74b, 76a, 76b ... Connection plates 78a, 78b, 80, 82a, 82b, 84a, 84b ... Cylindrical portion 86a ~ 86c ... Connecting pin

Claims (2)

Solid polymer fuel in which an electrolyte membrane / electrode structure provided with electrodes on both sides of an electrolyte membrane and a separator are stacked, and fuel gas and oxidant gas as reaction gases are supplied and a cooling medium is supplied A fuel cell system in which a battery and a flat membrane humidifier provided with a water permeable membrane for humidifying at least one reaction gas supplied to the polymer electrolyte fuel cell with a humidified fluid are stacked in the stacking direction. There,
An intermediate plate interposed between the polymer electrolyte fuel cell and the flat membrane humidifier;
A first connection plate that extends in the stacking direction with respect to the side of the polymer electrolyte fuel cell and holds the polymer electrolyte fuel cell;
A second connection plate that extends in the stacking direction with respect to the side of the flat membrane humidifier and holds the flat membrane humidifier;
With
The fuel cell, wherein the intermediate plate, the first connection plate, and the second connection plate are provided with a cylindrical portion that is disposed on the same axis and fixed with a connection pin inserted integrally. system. 2. The fuel cell system according to claim 1, wherein the polymer electrolyte fuel cell is stacked between the intermediate plate and the first end plate.
The flat membrane humidifier is laminated between the intermediate plate and the second end plate,
The first connection plate fixes the intermediate plate and the first end plate,
The fuel cell system, wherein the second connection plate fixes the intermediate plate and the second end plate.

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