JP2005190763A - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily and simply evade ground fault or liquid junction occurring in a fuel cell. <P>SOLUTION: A stack 14 of the fuel cell 10 is constituted including parallel pipe assembly 16. The parallel pipe assembly 16 has tube body 22, a first support frame body 46, and a second support frame body 48, and respective members 22, 46, 48 are made of PEEK resin which is an insulator. In the stack 14, the first mutual support frame 46 and the second mutual support frame 48 are adhered and laminated so that those apertures 42, 44 form the cooling medium outward passage 86 and the cooling medium backward passage 88, respectively. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fuel cell including a stack formed by stacking a plurality of unit power generation cells.

  In recent years, due to increasing interest in environmental protection, attempts have been made to replace the power source of automobiles with internal combustion engines by using fuel cells. A vehicle equipped with a fuel cell is generally referred to as a fuel cell vehicle.

  The electrolyte / electrode assembly of a fuel cell is configured by, for example, an electrolyte membrane made of a solid polymer membrane such as perfluorosulfonic acid polymer interposed between an anode side electrode and a cathode side electrode. A unit power generation cell is configured by sandwiching the electrolyte / electrode assembly between a pair of separators, and a stack is configured by stacking a plurality of unit power generation cells. A current collecting plate is disposed at each end of the stack, and one current collecting plate is electrically connected to the anode side electrode of each unit power generation cell, and the remaining one current collecting plate is connected to each unit power generation. It is electrically connected to the cathode side electrode of the cell.

  Here, when the electrolyte is a perfluorosulfonic acid polymer, the stack generally includes a cooling plate made of metal in addition to the unit power generation cell. Each time two to three unit power generation cells are stacked, the cooling plate is interposed at a ratio of one sheet, and in some cases, the cooling plate may be interposed between the unit power generation cells.

  The cooling plate is provided with a refrigerant passage for circulating the refrigerant. When the fuel cell is operated, the refrigerant flows through the refrigerant passage via a refrigerant supply / discharge system connected to the stack. Thereby, the operation temperature of the stack is maintained at 80 to 90 ° C. On the other hand, electrons generated in each unit power generation cell are taken out from the current collecting plate and become electric energy for energizing a load connected to the outside.

  By the way, when cooling a fuel cell in a fuel cell vehicle, it is assumed that water or coolant for a cooling mechanism is used as the refrigerant. However, since these liquids show conductivity because they contain impurity ions and metal additives, there is a concern that electricity flows in the refrigerant. When such a situation occurs, a ground fault or a liquid fault occurs and the output of the fuel cell decreases.

  Even when deionized water or pure water is used as the refrigerant, metal powder or the like is mixed into the refrigerant while the refrigerant is circulated through the cooling system piping or the radiator during the operation of the fuel cell. In particular, the refrigerant exhibits conductivity.

  In order to avoid such problems, Patent Document 1 proposes forming a glassy film in the refrigerant passage.

Japanese Patent Laid-Open No. 7-230818

  In the technique described in Patent Document 1, after a fuel cell is manufactured, a sol, which is a raw material of a film, is passed through a refrigerant passage and attached. Furthermore, after discharging excess sol, nitrogen gas heated to 150 ° C. is circulated through the refrigerant passage, whereby the sol adhering to the refrigerant passage is cross-linked and dried and solidified to provide a coating.

  However, there may be a bent portion in the refrigerant passage. Therefore, the work of passing the sol is complicated and takes a long time. Moreover, when discharging the sol, a part of the sol adhering to the refrigerant passage is also discharged, and as a result, there is a concern that there is a portion where a film is not formed. Of course, when such a situation occurs, it becomes difficult to avoid a ground fault or a liquid fault.

  That is, the technique described in Patent Document 1 has a problem that it is necessary to perform a complicated operation and it is not easy to form a film over the entire refrigerant passage.

  The present invention has been made to solve the above-described problem, and it is possible to easily and easily avoid a ground fault or a liquid fault, and to provide a fuel cell excellent in cooling efficiency. To do.

In order to achieve the above object, the present invention provides an anode side electrode to which a fuel gas is supplied, a cathode side electrode to which an oxidant gas is supplied, and an interposition between the anode side electrode and the cathode side electrode. And a pair of separators provided with a fuel gas supply path for supplying the fuel gas or an oxidant gas supply path for supplying the oxidant gas and sandwiching the assembly In a fuel cell comprising a stack in which a plurality of unit power generation cells comprising:
A plurality of pipes for circulating a refrigerant, a first support provided with an inlet for supporting the pipes and introducing refrigerant into the passages of the pipes; The stack includes a refrigerant circulation means having a second support body provided with a discharge port through which the refrigerant is discharged in communication with the passage of the tubular body.
The tube extends along a plane perpendicular to the stacking direction of the stack;
In addition, the tubular body is an insulator.

  By using a tubular body as an insulator, it is possible to prevent electricity from flowing from the stack to the refrigerant even when a conductive refrigerant is used. Can be avoided. As a result, deterioration of the power generation characteristics of the fuel cell is avoided.

  Moreover, according to the present invention, it is possible to avoid the occurrence of a ground fault or a liquid fault only by performing a simple operation of disposing the pipe body in the stack. For this reason, it is not necessary to provide a refrigerant passage in the stack, and it is not necessary to perform a complicated operation of providing a film in the refrigerant passage.

  Furthermore, in the present invention, the tubular body extends along the direction orthogonal to the stacking direction of the stack, that is, along the surface direction of the unit power generation cell. For this reason, since the unit cell is cooled over the entire surface direction, the stack can be efficiently cooled. The tubular body may be adjacent to the constituent member of the unit power generation cell, or may be embedded in the constituent member.

  A preferred example of the insulator is a resin. Specifically, a fluorine-containing resin or an aromatic resin is preferable.

  A preferred example of the electrolyte in the fuel cell configured to cool the stack from the inside is a solid polymer.

Further, the present invention provides a joined body having an anode side electrode to which a fuel gas is supplied, a cathode side electrode to which an oxidant gas is supplied, and an electrolyte interposed between the anode side electrode and the cathode side electrode. And a pair of separators that are provided with a fuel gas supply path for supplying the fuel gas or an oxidant gas supply path for supplying the oxidant gas and sandwich the assembly. In a fuel cell comprising a stack in which a plurality of layers are stacked,
A plurality of pipes for circulating the refrigerant, a first support provided with an inlet for supporting the pipes and introducing the refrigerant in communication with a passage of the pipes; The stack includes a refrigerant circulation means having a second support body provided with a discharge port through which the refrigerant is discharged in communication with the passage of the tubular body.
The tube extends along a plane perpendicular to the stacking direction of the stack;
And the insulating film is provided in the inner peripheral wall or the outer peripheral wall of the said tubular body, It is characterized by the above-mentioned.

  That is, in this case, the insulating film is provided on the inner peripheral wall or the outer peripheral wall of the tubular body so that the refrigerant flowing through the tubular body and the stack are insulated from each other. Therefore, it is possible to avoid the occurrence of a ground fault or a liquid fault as described above. Of course, excellent cooling efficiency can be ensured. In this case, a metal tube may be used.

  Preferable examples of the insulating film include those made of a resin. More specifically, a fluorine-containing resin or an aromatic resin is preferable.

  Similarly to the above, a solid polymer may be mentioned as a suitable example of the electrolyte in the fuel cell configured to cool the stack from the inside.

  According to the present invention, the refrigerant and the stack can be insulated from each other by performing a simple operation of disposing the tubular body which is an insulator or the tubular body provided with the insulating film in the stack. . For this reason, a ground fault and a liquid fault can be avoided. Moreover, since the tube body cools the surface direction of the stack, the cooling efficiency is also excellent.

  Preferred embodiments of the fuel cell according to the present invention will be described below in detail with reference to the accompanying drawings.

  A schematic overall perspective view of the fuel cell according to the present embodiment is shown in FIG. The fuel cell 10 has a stack 14 in which a plurality of unit power generation cells 12 are stacked in the direction of arrow A in FIG. Further, the stack 14 includes a pipe parallel assembly 16 for circulating refrigerant and a pipe support plate 18. Among these, the tube support plate 18 is provided with a recessed portion 20 that is recessed in a direction away from the separator 34 by providing a corrugated portion that continuously recesses and rises in the direction of arrow B in FIG. It has been. As shown in FIGS. 2 and 3, a tube body 22 constituting the tube parallel assembly 16 is inserted into the recess 20.

  As shown in FIGS. 3 and 4, the unit power generation cell 12 is an electrolyte / electrode in which a solid polymer electrolyte membrane 28 made of a perfluorosulfonic acid polymer is interposed between an anode side electrode 24 and a cathode side electrode 26. A joined body (hereinafter also referred to as MEA) 30 is provided, and the MEA 30 is held in an opening 33 of a gasket 32 made of polytetrafluoroethylene resin (PTFE).

  The MEA 30 is sandwiched between a pair of separators 34 and 36, and a first gas passage 38 through which hydrogen as a fuel gas flows is provided in the separator 34 that contacts the anode side electrode 24. On the other hand, the separator 36 in contact with the cathode side electrode 26 is provided with a second gas passage 40 through which air as an oxidant gas containing oxygen flows. And the said pipe | tube parallel aggregate 16 is arrange | positioned adjacent to the separator 34 among these.

  A spacer 41 is interposed between the end of the tube support plate 18 and the separator 34 to prevent air and hydrogen from leaking out.

  As shown in FIGS. 1, 2, and 5, the pipe parallel assembly 16 includes the pipe body 22, a first pipe body 22 that supports the pipe body 22 below and above, and is provided with openings 42 and 44, respectively. A first support frame 46 and a second support frame 48 are provided. A through-insertion hole 50 for inserting the tube body 22 is provided on one end face of the first support frame body 46 and the second support frame body 48 (see FIG. 5). The position is set to be flush with the inner wall surfaces of the openings 42 and 44 in the first support frame 46 and the second support frame 48. As will be described later, the refrigerant is introduced into the opening 42 of the first support frame 46, and the refrigerant is discharged from the opening 44 of the second support frame 48.

  As shown in FIG. 6, which is a horizontal sectional view of the tube body 22, the tube body 22 is a hollow body having a passage 52, and in this case, polyether ether ketone (PEEK) which is a kind of aromatic resin. Made of resin. The passage 52 communicates with the opening 42 of the first support frame 46 and the opening 44 of the second support frame 48. The first support frame body 46 and the second support frame body 48 are also made of PEEK resin, like the tube body 22.

  In the stack 14, three pipe parallel assemblies 16 having eight pipe bodies 22 are arranged in parallel, and two pipe parallel assemblies 16 having two pipe bodies 22 are arranged at both ends. The space between the adjacent tube parallel assemblies 16, 16 is slightly larger than that between the tubes 22 in the same tube parallel assembly 16 (see FIG. 2). The dimensions of the first support frame 46 and the second support frame 48 are set so as to slightly protrude from the gasket 32, the separators 34, 36, etc. in the height direction of the stack 14 (the direction of arrow C). .

  Each tubular body 22 extends in the direction of arrow C. That is, each tubular body 22 extends along the vertical direction of one end face of the separator 34 that intersects perpendicularly to the stacking direction (arrow A direction) of the stack 14.

  As described above, the tube support plate 18 is provided with a plurality of recesses 20 that cover the tube body 22 in the length direction, that is, in the direction of the arrow C (see FIGS. 1, 2, and 3). ). That is, each tubular body 22 is in contact with the separator 34 while being inserted into the recess 20 of the tubular body supporting plate 18.

  In the above configuration, the gasket 32, the separators 34, 36, the tube support plate 18, and the spacer 41 (see FIG. 3) in the lower left corner, the lower right corner, the upper left corner, and the upper right in FIGS. The corners are respectively supplied with a second gas discharge passage 54 for discharging air, a first gas discharge passage 56 for discharging hydrogen, a first gas supply passage 58 for supplying hydrogen, and air. A second gas supply passage 60 is provided for this purpose. Of course, the first gas supply passage 58 and the first gas discharge passage 56 communicate with the first gas passage 38, and the second gas supply passage 60 and the second gas discharge passage 54 communicate with the second gas passage 40. doing.

  The unit power generation cells 12 and the tube support plates 18 described above are alternately stacked. Further, current collecting plates 66 and 68 having tab portions 62 and 64, insulating sheets (not shown), and end plates 70 and 72 are provided. A backup plate 74 is further provided on each end, and further on the end plate 70 side. The end plate 72 and the backup plate 74 are fastened via a tie rod 76 shown in FIGS. 1 and 2 to form the stack 14. The upper end surface and the lower end surface of the stack 14 are provided with recesses 77 for avoiding the stack 14 from interfering with the tie rod 76. The tie rod 76 is passed between the pipe bodies 22 and 22 between the adjacent pipe parallel assemblies 16 and 16.

  Among these, the current collecting plate 66 is electrically connected to the anode side electrode 24 of each unit power generation cell 12, and the current collecting plate 68 is electrically connected to the cathode side electrode 26.

  Further, a second gas exhaust port 78 for exhausting air and a first gas exhausting hydrogen are respectively provided at the lower left corner, the lower right corner, the upper left corner, and the upper right corner of the end plate 70 in FIG. A gas discharge port 80, a first gas supply port 82 for supplying hydrogen, and a second gas supply port 84 for supplying air are provided. The second gas discharge port 78, the first gas discharge port 80, the first gas supply port 82, and the second gas supply port 84 are connected to the second gas discharge passage 54, the first gas discharge passage 56, the first gas supply passage 58, Needless to say, the second gas supply passages 60 communicate with each other.

  The backup plate 74 is formed in a shape that does not block the second gas discharge port 78, the first gas discharge port 80, the first gas supply port 82, and the second gas supply port 84 provided in the end plate 70. .

  As shown in FIG. 2, when the stack 14 is formed, the first support frame bodies 46 and the second support frame bodies 48 of the pipe parallel assembly 16 come into contact with each other. When the stack 14 is tightened by the tie rod 76, the first support frame bodies 46 and the second support frame bodies 48 are in close contact with each other in a liquid-tight state, whereby the openings 42 of the first support frame body 46 are in contact with each other. A continuous refrigerant forward path 86 (see FIG. 1) and a refrigerant return path 88 in which the openings 44 of the second support frame 48 are connected to each other are formed.

  A refrigerant supply jig 90 is disposed in one opening of the refrigerant forward path 86, and a first closing jig 92 is disposed in the other opening. The refrigerant return path 88 is provided with a refrigerant discharge jig 94 at an opening on the side where the refrigerant supply jig 90 is provided, and on the side where the first closing jig 92 is provided. A second closing jig 96 is disposed in the opening. The refrigerant supply jig 90 and the first closing jig 92, and the refrigerant discharge jig 94 and the second closing jig 96 are connected by tie rods 97, respectively.

  The coolant supply jig 90 has a joint portion 98 to which a coolant supply source (not shown) and a pipe (not shown) for bridging the coolant supply jig 90 are connected. The connecting part 100 radially expanded from 98 is a hollow body. That is, a chamber (not shown) is formed inside the connecting portion 100, and the chamber communicates with the refrigerant forward path 86. One refrigerant discharge jig 94 is configured in substantially the same manner as the refrigerant supply jig 90, and includes a joint portion 102 and a connecting portion 104.

  The fuel cell 10 according to the present embodiment is basically configured as described above. Next, the function and effect will be described.

  When the fuel cell 10 is operated, hydrogen is supplied from a hydrogen supply source (not shown), such as a hydrogen gas cylinder, to the first gas supply port 82, and second gas is supplied from an air supply source (not shown), such as a compressor. Air is supplied to the mouth 84. Hydrogen reaches the anode side electrode 24 via the first gas passage 38, while air reaches the cathode side electrode 26 via the second gas passage 40. The anode side electrode 24 undergoes an ionization reaction of hydrogen, and electrons generated thereby are taken out from the current collecting plate 66 to energize a load (not shown) electrically connected to the tab portions 62 and 64. Used as electrical energy.

  Then, the proton moves through the solid polymer electrolyte membrane 28 and reaches the cathode side electrode 26, via oxygen in the air supplied to the cathode side electrode 26 and the tab portion 64 of the current collecting plate 68. It reacts with the electrons that have reached the cathode side electrode 26 to generate moisture.

  Unreacted hydrogen is discharged from the first gas passage 38 via the first gas discharge port 80. In addition, moisture, unreacted oxygen, and nitrogen in the air generated by the cathode electrode 26 are discharged from the second gas passage 40 via the second gas discharge port 78.

  While hydrogen and air are circulated as described above, a coolant such as cooling water is circulated inside the stack 14. That is, the cooling water sent from a cooling water supply source (not shown) passes through the chamber in the connecting portion 100 of the refrigerant supply jig 90 and is introduced into the refrigerant forward path 86.

  Since one end portions of the refrigerant forward path 86 and the refrigerant return path 88 are respectively closed by the first closing jig 92 and the second closing jig 96, the cooling water is supplied from the openings 42 of the first support frame bodies 46. It flows through the passage 52 (see FIG. 6) of the tubular body 22 and rises from below along the height direction of the stack 14 (the direction of arrow C in FIG. 2). Thereby, the unit power generation cell 12 is cooled through the separator 34 adjacent to the pipe parallel assembly 16.

  The rising cooling water is discharged from the passages 52 of the pipe bodies 22 to the openings 44 of the second support frame bodies 48 and guided to the refrigerant return path 88, and then in the connecting portion 104 in the refrigerant discharge jig 94. It passes through the chamber and is discharged from the joint portion 102.

  In the above cooling water flow process, since the pipe body 22, the first support frame body 46, and the second support frame body 48 are made of PEEK resin, electricity does not flow through the pipe parallel assembly 16. In other words, even if a conductive material such as water is used as the coolant, a ground fault or liquid junction is caused by circulating the coolant through the stack 14 through the insulating pipe parallel assembly 16. It can be avoided.

  Thus, in this Embodiment, since the pipe body 22 for distribute | circulating a refrigerant | coolant is comprised with the insulator, it can prevent easily and constantly that a ground fault or a liquid junction arises.

  Moreover, according to the present embodiment, the complicated operation of providing the insulating film in the refrigerant passage is performed by performing the extremely simple and easy operation of disposing the pipe parallel assembly 16 in the stack 14. It is possible to avoid the occurrence of a ground fault or a liquid fault and the stack 14 can be reliably cooled. In addition, since it is not necessary to provide a coolant passage in the gasket 32, the separators 34, 36, etc., it is extremely easy to manufacture the stack 14.

  In the above-described embodiment, the tubular body 22 is made of PEEK resin, but may be made of fluorine-containing resin such as polytetrafluoroethylene (PTFE) resin. Then, as shown in FIG. 7 or FIG. 8, the tube 22 may be made of metal, and an insulating film 110 made of PEEK resin, fluorine-containing resin, or the like may be provided on the inner peripheral wall or the outer peripheral wall. The same applies to the first support frame 46 and the second support frame 48.

  Further, it is not particularly necessary that the tube body 22 is adjacent to the separator 34. For example, as shown in FIG. 9, the tube body 22 may be buried in the solid polymer electrolyte membrane 28. In this case, the pipe parallel assembly 16 may be placed at the time when the solid polymer electrolyte membrane 28 is formed about half, and the film formation is resumed to form the remaining half. In FIG. 9, reference numerals 112 and 114 denote a gas diffusion layer and an electrode catalyst layer constituting the anode side electrode 24 or the cathode side electrode 26, respectively. The same applies to the following drawings.

  Alternatively, as shown in FIGS. 10 and 11, the tube body 22 may be buried in the gas diffusion layer 112 or the electrode catalyst layer 114 of the anode side electrode 24 or the cathode side electrode 26.

  Furthermore, the tube body 22 extends along the lateral direction of the stack 14 (the direction of arrow C in FIG. 1), and as shown in FIG. 12, the first gas passage 38 or the second gas passage 40 of the separators 34, 36. You may make it insert the tubular body 22 in this. Alternatively, as shown in FIGS. 13 and 14, the tube body 22 may be buried in the separators 34 and 36.

  The fuel cell 10 having each configuration described above can be used by being mounted on an automobile, for example.

1 is a schematic overall perspective view of a fuel cell according to an embodiment. 1 is an overall perspective view showing a schematic configuration of a fuel cell according to an embodiment. FIG. 2 is a plan sectional view of the stack of FIG. 1. FIG. 2 is an explanatory perspective view showing a schematic configuration of a unit power generation cell constituting the fuel cell of FIG. 1. FIG. 2 is an overall schematic perspective view of a pipe parallel assembly disposed in the stack of FIG. 1. FIG. 6 is a horizontal sectional view of the tubular body of FIG. 5. It is a horizontal direction sectional view of a pipe object in a fuel cell concerning another embodiment. It is a horizontal direction sectional view of a pipe object in a fuel cell concerning another embodiment. It is a plane sectional view of a stack which shows the arrangement position of a pipe in a fuel cell concerning another embodiment. It is a plane sectional view of a stack which shows the arrangement position of a pipe in a fuel cell concerning another embodiment. It is a plane sectional view of a stack which shows the arrangement position of a pipe in a fuel cell concerning another embodiment. It is a longitudinal cross-sectional view of the stack which shows the arrangement | positioning position of the tubular body in the fuel cell which concerns on another embodiment. It is a longitudinal cross-sectional view of a stack | stuck which shows the arrangement | positioning position of the pipe body in the fuel cell which concerns on embodiment different from the fuel cell of FIGS. 9-12. It is a longitudinal cross-sectional view of a stack | stuck which shows the arrangement | positioning position of the pipe body in the fuel cell which concerns on embodiment different from the fuel cell of FIGS. 9-13.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fuel cell 12 ... Unit power generation cell 14 ... Stack 16 ... Pipe parallel assembly 18 ... Plate support plate 20 ... Recess 22 ... Tube 24 ... Anode side electrode 26 ... Cathode side electrode 28 ... Solid polymer electrolyte membrane 30 Electrolyte / electrode assembly 34, 36 Separator 42, 44 ... Opening 46, 48 ... Support frame 52 ... Passage 66, 68 ... Current collecting plate 86 ... Refrigerant forward path 88 ... Refrigerant return path 90 ... Refrigerant supply jig 92 96 ... Closure jig 94 ... Refrigerant discharge jig 112 ... Gas diffusion layer 114 ... Electrode catalyst layer

Claims (8)

An anode-side electrode to which fuel gas is supplied; a cathode-side electrode to which oxidant gas is supplied; and a joined body having an electrolyte interposed between the anode-side electrode and the cathode-side electrode; and the fuel gas A stack in which a plurality of unit power generation cells having a fuel gas supply path for supplying or an oxidant gas supply path for supplying the oxidant gas and having a pair of separators sandwiching the assembly are stacked In a fuel cell comprising:
A plurality of pipes for circulating a refrigerant, a first support provided with an inlet for supporting the pipes and introducing refrigerant into the passages of the pipes; The stack includes a refrigerant circulation means having a second support body provided with a discharge port through which the refrigerant is discharged in communication with the passage of the tubular body.
The tube extends along a plane perpendicular to the stacking direction of the stack;
The fuel cell is characterized in that the tubular body is an insulator.   2. The fuel cell according to claim 1, wherein the tube is made of a resin.   3. The fuel cell according to claim 2, wherein the tubular body is made of a fluorine-containing resin or an aromatic resin.   The fuel cell according to any one of claims 1 to 3, wherein the electrolyte is a solid polymer. An anode-side electrode to which fuel gas is supplied; a cathode-side electrode to which oxidant gas is supplied; and a joined body having an electrolyte interposed between the anode-side electrode and the cathode-side electrode; and the fuel gas A stack in which a plurality of unit power generation cells having a fuel gas supply path for supplying or an oxidant gas supply path for supplying the oxidant gas and having a pair of separators sandwiching the assembly are stacked In a fuel cell comprising:
A plurality of pipes for circulating a refrigerant, a first support provided with an inlet for supporting the pipes and introducing refrigerant into the passages of the pipes; The stack includes a refrigerant circulation means having a second support body provided with a discharge port through which the refrigerant is discharged in communication with the passage of the tubular body.
The tube extends along a plane perpendicular to the stacking direction of the stack;
The fuel cell is characterized in that an insulating film is provided on an inner peripheral wall or an outer peripheral wall of the tubular body.   6. The fuel cell according to claim 5, wherein the insulating film is made of a resin.   The fuel cell according to claim 6, wherein the insulating film is made of a fluorine-containing resin or an aromatic resin. 8. The fuel cell according to claim 5, wherein the electrolyte is a solid polymer.

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