JP2006032054A - Fuel cell stack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow air mixed in a cooling medium to surely escape and a fuel stack to have a good cooling function with a simple structure. <P>SOLUTION: A piping manifold 46, on which a cooling medium supply port 58a is formed communicating with a cooling medium supply communication hole 30a, is placed on one end in the stacking direction of a fuel cell stack 10. The piping manifold 46 has the cooling medium supply port 58a and an air vent port 62, where the air vent port 62 is in a higher position than the cooling medium supply port 58a and communicates with the cooling medium supply communication hole 30a. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention has an electrolyte / electrode structure in which a pair of electrodes are disposed on both sides of an electrolyte, and the electrolyte / electrode structure and the separator are alternately stacked, and at least a cooling medium penetrates in the stacking direction. The present invention relates to a fuel cell stack in which a supply communication hole and a cooling medium discharge communication hole are formed.

  For example, in a polymer electrolyte fuel cell, an electrolyte membrane / electrode structure in which an anode side electrode and a cathode side electrode are provided on both sides of an electrolyte membrane (electrolyte) made of a polymer ion exchange membrane is sandwiched between separators. It has a power generation cell. 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. 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, a fuel gas channel for flowing fuel gas to the anode side electrode and an oxidant gas channel for flowing oxidant gas to the cathode side electrode are provided in the plane of the separator. . Furthermore, between the separators, a cooling medium flow path for flowing the cooling medium is provided along the surface direction of the separator.

  Generally, a fuel cell constitutes an internal manifold in which a fluid supply communication hole and a fluid discharge communication hole penetrating in the stacking direction of the separator are provided inside the fuel cell. The fuel gas, the oxidant gas, and the cooling medium, which are fluids, are supplied to the fuel gas flow path, the oxidant gas flow path, and the cooling medium flow path from the fluid supply communication holes, and then the fluid discharge communication holes. Have been discharged.

  As this type of internal manifold type fuel cell, “Fuel Cell Manifold” of Patent Document 1 is known. In Patent Document 1, as shown in FIG. 5, a single cell 1 configured by stacking a membrane-electrode assembly (MEA) and a separator is provided, and a stacking direction of a module 2 in which a plurality of single cells 1 are stacked is provided. A terminal 3, an insulator 4 and an end plate 5 are disposed at both ends, and a fuel cell stack 6 is configured.

  In the fuel cell stack 6, refrigerant manifolds 7 a and 7 b are provided penetrating in the stacking direction, and the refrigerant manifolds 7 a and 7 b communicate with a refrigerant flow path (not shown) provided in each single cell 1. ing. Refrigerant pipes 8a and 8b for supplying and discharging refrigerant to and from the refrigerant manifolds 7a and 7b are connected to the end plate 5 provided at one end of the fuel cell stack 6. The refrigerant supplied from the inlet side refrigerant pipe 8a to the refrigerant manifold 7a is introduced into the fuel cell stack 6, and after cooling each single cell 1, it is discharged from the refrigerant manifold 7b to the outlet side refrigerant pipe 8b.

Japanese Patent Laid-Open No. 2002-343406 (FIG. 1)

  However, in the above-mentioned Patent Document 1, when air is mixed in the refrigerant supplied from the refrigerant pipe 8a to the refrigerant manifold 7a, or when the refrigerant is injected after the fuel cell stack 6 is assembled, the air is mixed. The air may remain in the upper region of the refrigerant manifold 7a. Thereby, there exists a space part which does not have a cooling function in the upper part of the refrigerant | coolant manifold 7a, and there exists a problem that the whole electric power generation surface of each single cell 1 cannot be cooled favorably.

  The present invention solves this type of problem, and can provide a fuel cell stack that can reliably discharge air mixed in a cooling medium and can maintain a good cooling function with a simple configuration. The purpose is to provide.

  The present invention has an electrolyte / electrode structure in which a pair of electrodes are disposed on both sides of an electrolyte, and the electrolyte / electrode structure and the separator are alternately stacked, and at least a cooling medium penetrates in the stacking direction. It is a fuel cell stack in which a supply communication hole and a cooling medium discharge communication hole are formed.

  The fuel cell stack includes a manifold member provided with a cooling medium supply port communicating with the cooling medium supply communication hole, and the manifold member is located at a position higher than the cooling medium supply port in the cooling medium supply communication hole. An air vent is provided for communication.

  Further, the present invention has an electrolyte / electrode structure in which a pair of electrodes are disposed on both sides of the electrolyte, and the electrolyte / electrode structure and the separator are alternately stacked, and at least penetrates in the stacking direction. It is a fuel cell stack in which a cooling medium supply communication hole and a cooling medium discharge communication hole are formed.

  The fuel cell stack includes a manifold member provided with a cooling medium discharge port communicating with the cooling medium discharge communication hole, and the manifold member is located at a position higher than the cooling medium discharge port in the cooling medium discharge communication hole. An air vent is provided for communication.

  Furthermore, it is preferable that a pipe member having one end connected to the air vent port is provided, the pipe member is maintained at a position higher than the air vent port, and an opening / closing valve is mounted on the other end.

  Furthermore, it is preferable that the cooling medium supply communication hole and the cooling medium discharge communication hole communicate with a cooling medium circulation path that circulates outside the fuel cell stack.

  According to the present invention, when the cooling medium is supplied to the cooling medium supply port, the air mixed in the cooling medium moves vertically above the cooling medium supply port and is smoothly and reliably discharged from the air vent port. Is done. For this reason, air can be effectively prevented from being introduced into the cooling medium supply communication hole, and the cooling efficiency of the entire fuel cell stack can be improved satisfactorily with a simple configuration.

  Further, according to the present invention, when the cooling medium is discharged to the cooling medium discharge port, the air mixed in the cooling medium moves vertically above the cooling medium discharge port and smoothly and reliably passes through the air discharge port. To be discharged. Therefore, when the cooling medium is circulated from the cooling medium discharge port to the cooling medium supply port, it is possible to effectively prevent air from being introduced into the cooling medium supply communication hole. As a result, the cooling efficiency of the entire fuel cell stack is improved with a simple configuration.

  FIG. 1 is a schematic perspective view of a fuel cell system 12 incorporating a fuel cell stack 10 according to the first embodiment of the present invention.

  The fuel cell system 12 is mounted on a vehicle such as an automobile, for example, and includes a fuel cell stack 10 connected to the coolant circulation supply unit 14. Although not shown, the fuel cell stack 10 includes an oxidant gas supply unit that supplies an oxidant gas, for example, an oxygen-containing gas (such as air), and a fuel gas supply unit that supplies a fuel gas, for example, a hydrogen-containing gas. Is connected.

  The fuel cell stack 10 includes a stacked body 18 in which a plurality of power generation cells 16 are stacked in the direction of arrow A, and end plates 20 a and 20 b are disposed at both ends of the stacked body 18 in the stacking direction. The end plates 20a and 20b are fastened in the stacking direction by fastening bolts (not shown).

  As shown in FIG. 2, each power generation cell 16 includes an electrolyte membrane / electrode structure (electrolyte / electrode structure) 22, and a thin plate-shaped first and second metal sandwiching the electrolyte membrane / electrode structure 22. Separators 24 and 26 are provided.

  In order to supply an oxidant gas supply communication hole 28a for supplying an oxidant gas to one end edge of the power generation cell 16 in the long side direction (arrow B direction) and for supplying an oxidant gas to each other in the arrow A direction. The cooling medium supply communication hole 30a and the fuel gas discharge communication hole 32b for discharging the fuel gas are provided.

  The other end edge in the long side direction of the power generation cell 16 communicates with each other in the direction of the arrow A, the fuel gas supply communication hole 32a for supplying fuel gas, and the cooling medium discharge communication hole for discharging the cooling medium. 30b and an oxidant gas discharge communication hole 28b for discharging the oxidant gas are provided.

  The electrolyte membrane / electrode structure 22 includes, for example, a solid polymer electrolyte membrane 34 in which a perfluorosulfonic acid thin film is impregnated with water, and an anode side electrode 36 and a cathode side electrode 38 that sandwich the solid polymer electrolyte membrane 34. With.

  The anode side electrode 36 and the cathode side electrode 38 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 a platinum alloy on the surface. And an electrode catalyst layer (not shown) formed. The electrode catalyst layers are formed on both sides of the solid polymer electrolyte membrane 34.

  The first metal separator 24 is provided with a fuel gas flow path 40 that communicates the fuel gas supply communication hole 32 a and the fuel gas discharge communication hole 32 b on the surface facing the electrolyte membrane / electrode structure 22. The first metal separator 24 is provided with a cooling medium flow path 42 that communicates the cooling medium supply communication hole 30a and the cooling medium discharge communication hole 30b on the opposite surface.

  The second metal separator 26 is provided with an oxidant gas flow path 44 on the surface facing the electrolyte membrane / electrode structure 22, and the oxidant gas flow path 44 communicates with the oxidant gas supply communication hole 28 a and the oxidant gas discharge communication. It communicates with the hole 28b. The second metal separator 26 overlaps with the first metal separator 24 on the opposite surface, and the cooling medium flow path 42 is integrally formed.

  The fuel gas flow path 40, the cooling medium flow path 42, and the oxidant gas flow path 44 are configured by, for example, a plurality of grooves extending in the direction of arrow B. Sealing members (not shown) are integrally formed on the surfaces of the first and second metal separators 24 and 26.

  A plurality of screw holes 45a are formed in the end plate 20a to surround the oxidant gas supply communication hole 28a, the cooling medium supply communication hole 30a, and the fuel gas discharge communication hole 32b. A plurality of screw holes 45b are formed surrounding the medium discharge communication hole 30b and the oxidant gas discharge communication hole 28b.

  Piping manifolds (manifold members) 46 and 48 are fixed to the end plate 20 a on the surface opposite to the stacked body 18. The piping manifolds 46 and 48 are provided with mounting plate-like portions 50a and 50b arranged at both ends in the lateral direction (arrow B direction) of the end plate 20a. A plurality of holes 52a and 52b are formed coaxially with the screw holes 45a and 45b of the end plate 20a in each of the mounting plate-like parts 50a and 50b. Screws 54 are inserted into the holes 52a and 52b, and the ends of the screws 54 are screwed into the screw holes 45a and 45b, whereby the pipe manifolds 46 and 48 are fixed to the end plate 20a.

  As shown in FIGS. 2 and 3, the piping manifold 46 has an oxidant gas supply communication hole 28a, an oxidant gas supply port 56a communicating with the cooling medium supply communication hole 30a and the fuel gas discharge communication hole 32b, and a cooling medium supply. A port 58a and a fuel gas discharge port 60b are formed.

  The pipe manifold 46 is provided with an air vent port 62 that communicates with the coolant supply passage 30a at a position higher than the coolant supply port 58a. The oxidant gas supply port 56a, the cooling medium supply port 58a, and the fuel gas discharge port 60b are formed in the cylindrical portion, and the air vent port 62 is formed in the small-diameter cylindrical portion.

  As shown in FIG. 2, the pipe manifold 48 has a fuel gas supply port 60a, a coolant discharge port 58b, and an oxidation port that communicate with the fuel gas supply passage 32a, the coolant discharge passage 30b, and the oxidant gas discharge passage 28b. An agent gas discharge port 56b is formed.

  As shown in FIG. 1, the cooling medium circulation supply unit 14 includes a supply pipe 64a connected to the cooling medium supply port 58a and a discharge pipe 64b connected to the cooling medium discharge port 58b, and the supply pipe 64a. And the discharge pipe 64b are connected to a circulation pump 66.

  The oxidant gas supply port 56a and the oxidant gas discharge port 56b are connected to an oxidant gas supply unit (not shown), while the fuel gas supply port 60a and the fuel gas discharge port 60b are connected to a fuel gas supply unit (not shown). Connected.

  One end of a piping member 68 is connected to the air vent port 62. The piping member 68 is maintained at a position (in the direction of the arrow C1) higher than the height position P of the air vent port 62, and an opening / closing valve 70 is attached to the other end and can be opened outside the vehicle. The on-off valve 70 is opened when air is vented from the piping member 68 or when the cooling medium is filled in the fuel cell stack 10.

  The operation of the fuel cell system 12 configured as described above will be described below.

  First, the oxidant gas is supplied from the oxidant gas supply port 56 a to the oxidant gas supply communication hole 28 a of the fuel cell stack 10. On the other hand, the fuel gas is supplied from the fuel gas supply port 60 a to the fuel gas supply communication hole 32 a of the fuel cell stack 10.

  As shown in FIG. 2, in the fuel cell stack 10, oxidant gas is introduced into the oxidant gas flow path 44 of the second metal separator 26 from the oxidant gas supply communication hole 28 a, and the electrolyte membrane / electrode structure 22. It moves along the cathode side electrode 38. On the other hand, the fuel gas is introduced into the fuel gas flow path 40 of the first metal separator 24 from the fuel gas supply communication hole 32 a and moves along the electrolyte membrane / electrode structure 22 anode side electrode 36.

  Therefore, in each electrolyte membrane / electrode structure 22, the oxidant gas supplied to the cathode side electrode 38 and the fuel gas supplied to the anode side electrode 36 are consumed by an electrochemical reaction in the electrode catalyst layer, Power generation is performed.

  Next, the oxidant gas supplied and consumed to the cathode side electrode 38 flows along the oxidant gas discharge communication hole 28b, and is then discharged to the oxidant gas discharge port 56b connected to the end plate 20a. Similarly, the fuel gas consumed by being supplied to the anode side electrode 36 is discharged to the fuel gas discharge communication hole 32b, flows, and discharged to the fuel gas discharge port 60b connected to the end plate 20a.

  Further, as shown in FIG. 1, a cooling medium such as pure water or ethylene glycol is sent from the supply pipe 64 a to the cooling medium supply port 58 a under the action of the pump 66 that constitutes the cooling medium circulation supply unit 14. The cooling medium supply communication hole 30a in the battery stack 10 is supplied. As shown in FIG. 2, the cooling medium flows into the cooling medium flow path 42 between the first and second metal separators 24 and 26 and then flows along the direction of arrow B. This cooling medium cools the electrolyte membrane / electrode structure 22, and then moves through the cooling medium discharge communication hole 30b and is discharged from the cooling medium discharge port 58b connected to the end plate 20a to the discharge pipe 64b for circulation. The

  In this case, the first embodiment includes a pipe manifold 46 fixed to the end plate 20a. The pipe manifold 46 is provided with a cooling medium supply port 58a communicating with the cooling medium supply communication hole 30a. An air vent port 62 communicating with the cooling medium supply communication hole 30a is provided at a position higher than the cooling medium supply port 58a.

  For this reason, when the cooling medium is supplied to the cooling medium supply port 58a via the cooling medium circulation supply unit 14, the air mixed in the cooling medium moves above the cooling medium supply port 58a and moves to the air vent port. 62 is smoothly and reliably discharged.

  As a result, it is possible to effectively prevent air from being introduced into the cooling medium supply communication hole 30a, and the effect of improving the cooling efficiency of the entire fuel cell stack 10 with a simple configuration can be obtained.

  Furthermore, in the first embodiment, the piping member 68 whose one end is connected to the air vent port 62 is maintained at a position higher than the height of the air vent port 62. Therefore, air venting and the like in the piping member 68 are performed satisfactorily. In the first embodiment, the position of the air vent 62 is set based on the height direction when the fuel cell stack 10 is installed.

  FIG. 4 is a schematic perspective view of a fuel cell system 82 incorporating a fuel cell stack 80 according to the second embodiment of the present invention. The same components as those of the fuel cell system 12 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the fuel cell stack 80, an air vent port 84 that communicates with the coolant discharge passage 30b is provided at a position where the pipe manifold 48 is higher than the coolant discharge port 58b. One end of a pipe member 86 is connected to the air vent port 84. The pipe member 86 is maintained above the height position P of the air vent port 84, and an opening / closing valve 88 is provided at the other end. The

  In the second embodiment configured as described above, the cooling medium circulation supply unit 14 circulates the cooling medium from the discharge pipe 64 b to the supply pipe 64 a, and the cooling medium is supplied into the fuel cell stack 80. Here, the air mixed in the cooling medium moves above the cooling medium discharge port 58 b and is smoothly and reliably discharged from the air vent port 84. At that time, the air pressure is adjusted by controlling the on-off valve 88, so that the air venting process can be satisfactorily performed from the air vent port 84 to the outside of the vehicle.

  Thereby, air is not mixed in the cooling medium circulated from the cooling medium discharge port 58b to the cooling medium supply port 58a, and air is reliably prevented from being introduced into the cooling medium supply communication hole 30a. And the same effect as the first embodiment can be obtained.

  In the first and second embodiments, the air vent ports 62 and 84 are provided independently without overlapping the cooling medium supply port 58a and the cooling medium discharge port 58b. A part thereof may be provided so as to overlap with the height direction of the opening 58a and the cooling medium discharge port 58b.

1 is a schematic perspective view of a fuel cell system incorporating a fuel cell stack according to a first embodiment of the present invention. It is a principal part disassembled perspective view of the said fuel cell stack. FIG. 2 is a cross-sectional explanatory view of a piping manifold that constitutes the fuel cell stack. It is a schematic perspective view of the fuel cell system incorporating the fuel cell stack which concerns on the 2nd Embodiment of this invention. 6 is a schematic explanatory diagram of a manifold of a fuel cell of Patent Document 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,80 ... Fuel cell stack 12, 82 ... Fuel cell system 14 ... Cooling medium circulation supply part 16 ... Power generation cell 20a, 20b ... End plate 22 ... Electrolyte membrane and electrode structure 24, 26 ... Separator 28a ... Oxidant gas supply Communication hole 28b ... Oxidant gas discharge communication hole 30a ... Cooling medium supply communication hole 30b ... Cooling medium discharge communication hole 32a ... Fuel gas supply communication hole 32b ... Fuel gas discharge communication hole 34 ... Solid polymer electrolyte membrane 36 ... Anode side electrode 38 ... Cathode side electrode 40 ... Fuel gas flow path 42 ... Cooling medium flow path 44 ... Oxidant gas flow path 46, 48 ... Pipe manifold 56a ... Oxidant gas supply port 56b ... Oxidant gas discharge port 58a ... Cooling medium supply port 58b ... Cooling medium discharge port 60a ... Fuel gas supply port 60b ... Fuel gas discharge port 62, 84 ... Air vent 64a ... Supply piping 6 b ... exhaust pipe 66 ... pump 68,86 ... piping member 70,88 ... off valve

Claims (4)

An electrolyte / electrode structure having a pair of electrodes disposed on both sides of the electrolyte, and alternately stacking the electrolyte / electrode structure and the separator, and penetrating in the stacking direction; A fuel cell stack in which a cooling medium discharge communication hole is formed,
A manifold member provided with a cooling medium supply port communicating with the cooling medium supply communication hole;
The fuel cell stack, wherein the manifold member is provided with an air vent port communicating with the coolant supply passage at a position higher than the coolant supply port. An electrolyte / electrode structure having a pair of electrodes disposed on both sides of the electrolyte, and alternately stacking the electrolyte / electrode structure and the separator, and penetrating in the stacking direction; A fuel cell stack in which a cooling medium discharge communication hole is formed,
A manifold member provided with a cooling medium discharge port communicating with the cooling medium discharge communication hole;
The fuel cell stack, wherein the manifold member is provided with an air vent port communicating with the coolant discharge passage at a position higher than the coolant discharge port. The fuel cell stack according to claim 1 or 2, further comprising a piping member having one end connected to the air vent.
The piping member is maintained at a position higher than the air vent, and an open / close valve is attached to the other end of the fuel cell stack. 4. The fuel cell stack according to claim 1, wherein the coolant supply passage and the coolant discharge passage communicate with a coolant circulation path that circulates outside the fuel cell stack. 5. A fuel cell stack characterized by

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