JP5734690B2 - Fuel cell system - Google Patents

Description

  The present invention includes a fuel cell stack having an electrolyte / electrode structure in which a pair of electrodes are disposed on both sides of an electrolyte, and a power generation cell having the electrolyte / electrode structure and a separator, and the fuel cell. The present invention relates to a fuel cell system including a capacitance-type surface pressure measuring device disposed in a stack and measuring a surface pressure of the power generation cell.

  For example, in a polymer electrolyte fuel cell, an electrolyte membrane / electrode structure (MEA) in which an anode side electrode and a cathode side electrode are disposed on both sides of an electrolyte membrane (electrolyte) made of a polymer ion exchange membrane is used as a separator. A power generation cell sandwiched between the two. In this type of fuel cell, a predetermined number of power generation cells are usually stacked, and a terminal plate, an insulating plate, and an end plate are disposed at both ends in the stacking direction to constitute a fuel cell stack. The fuel cell stack is mounted on a fuel cell vehicle such as a fuel cell vehicle.

  In this fuel cell stack, a clamping load is applied between the pair of end plates in the stacking direction of the power generation cells by a clamping bolt, a casing, or the like. At that time, if the surface pressure of the electrode surface of the power generation cell varies (surface pressure distribution), the contact resistance may increase and the terminal voltage may decrease.

  Therefore, it is necessary to measure the surface pressure distribution in the fuel cell stack. For example, a fuel cell stack disclosed in Patent Document 1 is known. As shown in FIG. 13, this fuel cell stack includes a surface pressure sensor module 1, and the surface pressure sensor module 1 is provided at an arbitrary position in the stacking direction of fuel cells (not shown), for example, approximately in the center. ing. In the surface pressure sensor module 1, a surface pressure sensor 4 is disposed between a pair of separators 2 via a recess 3.

  The surface pressure sensor 4 is configured by covering a capacitor type or strain gauge sensor 5 with a resin 6. For example, two surface pressure sensors 4 are sandwiched between the separators 2, and the surface pressure distribution in the fuel cell can be measured via the surface pressure sensor 4.

JP 2006-120346 A

  However, in Patent Document 1 described above, the pair of separators 2 constituting the surface pressure sensor module 1 are provided with the recesses 3 for disposing the surface pressure sensor 4, and the separators used for other fuel cells Have different configurations. Therefore, a dedicated separator 2 must be prepared for the surface pressure sensor module 1, which is not economical.

  Further, although it is described that two or more surface pressure sensors 4 are arranged in the surface of the separator 2, this type of surface pressure sensor 4 covers the sensor 5 with a resin 6 and leads 7. Is provided. For this reason, it is substantially difficult to dispose a large number of surface pressure sensors 4 in the surface of the separator 2, and there is a problem that the surface pressure in the power generation surface cannot be measured with high accuracy.

  On the other hand, normally, when a large number of sensors are arranged, normal current distribution during power generation is hindered. As a result, a large current may be applied locally, and damage due to Joule heat may occur.

  The present invention solves this type of problem, and provides a fuel cell system capable of measuring the surface pressure distribution in the fuel cell stack with high accuracy and reliability and capable of obtaining a high-performance fuel cell stack. The purpose is to provide.

  The present invention includes a fuel cell stack having an electrolyte / electrode structure in which a pair of electrodes are disposed on both sides of an electrolyte, and a power generation cell having the electrolyte / electrode structure and a separator, and the fuel cell. The present invention relates to a fuel cell system including a capacitance type surface pressure measuring device disposed in a stack and measuring the surface pressure of the power generation cell.

In this fuel cell system, the capacitance-type surface pressure measuring device includes a plurality of dielectrics provided in the power generation surface of the power generation cell, and extends along the power generation surface direction of the power generation cell. A conductive portion for passing a current between the dielectrics in the laminating direction; a plurality of elongated first electrodes and a plurality of first electrodes that sandwich the dielectric from both sides of the laminating direction and extend perpendicular to each other. Two electrodes, a plurality of elongated metal first shield members, and a plurality of elongated metal first shield members that extend in directions orthogonal to each other, and are laminated on the outer sides of the first electrode and the second electrode, respectively. A metal second shield member, and between the adjacent first electrodes and between the adjacent second electrodes, the conductive portion is disposed, and the first circuit pattern connected to each first electrode is: Connected to the end of the first electrode. A plurality of first wiring portion, a first wiring portion of said plurality, while being set to the same surface area and the same length with each other, the second circuit pattern connected to the second electrode, the second A plurality of second wiring portions connected to the end portions of the electrodes are provided, and the plurality of second wiring portions are set to have the same length and the same surface area.

  According to the present invention, the capacitance-type surface pressure measuring device includes a metal first shield member and a metal, with an insulating sheet interposed between the first electrode and the second electrode provided on both sides of the dielectric, respectively. A second shield member made is laminated. For this reason, it is possible to perform stable measurement satisfactorily and reliably without being affected by external noise.

  As a result, it is possible to satisfactorily measure the surface pressure in the power generation surface covering the use load region of the fuel cell stack. Therefore, a normal current is not inhibited during power generation, and the surface pressure distribution in the fuel cell stack can be measured with high accuracy and reliability.

1 is an explanatory perspective view of a fuel cell system according to an embodiment of the present invention. It is a partial cross section explanatory view of the fuel cell system. It is a disassembled perspective explanatory drawing of the electric power generation cell which comprises the said fuel cell system. It is a principal part disassembled perspective view of the electrostatic capacitance type surface pressure measuring apparatus which comprises the said fuel cell system. It is a principal part perspective view of the said electrostatic capacitance type surface pressure measuring apparatus. FIG. 6 is a cross-sectional view of the capacitance-type surface pressure measuring device taken along line VI-VI in FIG. 5. It is front explanatory drawing of the said electrostatic capacitance type surface pressure measuring apparatus. It is a principal part disassembled perspective view of the said capacitance-type surface pressure measuring apparatus. It is sectional drawing explaining another structure of the said electrostatic capacitance type surface pressure measuring apparatus. It is sectional drawing explaining the other structure of the said electrostatic capacitance type surface pressure measuring apparatus. It is sectional drawing explaining another structure of the said electrostatic capacitance type surface pressure measuring apparatus. It is sectional drawing explaining the further another structure of the said electrostatic capacitance type surface pressure measuring apparatus. 1 is a cross-sectional view of a main part of a fuel cell system disclosed in Patent Document 1. FIG.

  As shown in FIGS. 1 and 2, a fuel cell system 10 according to an embodiment of the present invention includes a fuel cell stack 12, and a capacitance type surface pressure measuring device 14 disposed in the fuel cell stack 12. Is provided. The fuel cell system 10 is mounted on a fuel cell vehicle such as a fuel cell vehicle (not shown), for example.

  In the fuel cell stack 12, a plurality of power generation cells 16 are stacked in the direction of arrow A, and end plates 20a and 20b are arranged at both ends in the stacking direction with terminal plates 17a and 17b and insulating plates 18a and 18b interposed therebetween. (See FIG. 2).

  The end plates 20a and 20b are fastened in the stacking direction by a plurality of fastening bolts 21a, for example. The end plate 20b is formed with a screw hole (not shown) into which the fastening bolt 21a is screwed. Alternatively, a through hole may be formed in the end plate 20b, and a nut (not shown) may be screwed to the tip of the fastening bolt 21a.

  Further, a clamping load may be applied by interposing a plate (not shown) between the end plates 20a and 20b and adjusting the distance between the end plates 20a and 20b. Further, a load may be applied between the end plate 20a and the insulating plate 18a or between the end plate 20b and the insulating plate 18b via a disc spring (not shown).

  As shown in FIGS. 2 and 3, each power generation cell 16 includes an electrolyte membrane / electrode structure 22, and a first separator 24 and a second separator 26 that sandwich the electrolyte membrane / electrode structure 22. Although the 1st separator 24 and the 2nd separator 26 are comprised by the carbon separator, for example, you may use a metal separator. Between the first separator 24 and the second separator 26, the electrolyte membrane / electrode structure 22 is accommodated and a gasket 27 is interposed.

  As shown in FIG. 3, an oxidant for supplying an oxidant gas, for example, an oxygen-containing gas (such as air) to one end edge of the power generation cell 16 in the direction of arrow B and communicating with each other in the direction of arrow A. A gas supply communication hole 28a, a cooling medium supply communication hole 30a for supplying a cooling medium such as pure water or ethylene glycol, and a fuel gas discharge communication hole 32b for discharging a fuel gas such as a hydrogen-containing gas are provided. Provided.

  The other end edge of the power generation cell 16 in the direction of the arrow B communicates with each other in the direction of the arrow A, the fuel gas supply communication hole 32a for supplying the 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 surfaces of the solid polymer electrolyte membrane 34.

  The first separator 24 is provided with a fuel gas flow path 40 on a surface 24 a facing the electrolyte membrane / electrode structure 22. The fuel gas channel 40 has a plurality of channel grooves extending in the direction of arrow B, and communicates with the fuel gas supply communication hole 32a and the fuel gas discharge communication hole 32b. A cooling medium flow path 42 is formed on the surface 24 b of the first separator 24. The cooling medium flow path 42 has a plurality of flow path grooves extending in the direction of arrow B, and communicates with the cooling medium supply communication hole 30a and the cooling medium discharge communication hole 30b.

  In the second separator 26, an oxidant gas flow path 44 is formed on the surface 26 a facing the electrolyte membrane / electrode structure 22. The oxidant gas flow path 44 has a plurality of flow path grooves extending in the direction of arrow B, and communicates with the oxidant gas supply communication hole 28a and the oxidant gas discharge communication hole 28b. The surface 26b of the second separator 26 is configured to be flat.

  As shown in FIG. 2, the capacitance-type surface pressure measuring device 14 is arranged at the approximate center of the power generation cells 16 stacked in the fuel cell stack 12. As shown in FIGS. 4 and 5, the capacitance-type surface pressure measuring device 14 accommodates a plurality of dielectrics 50 that are located in the power generation surface of the power generation cell 16 and arranged in the directions of arrows B and C. Conductive portions 52, a plurality of first electrodes 54 and second electrodes 56 that sandwich the dielectric 50 integrally from both sides, and insulating members 58a on the outside of the first electrodes 54 and the second electrodes 56, respectively. The first shield member 60 and the second shield member 62 are provided so as to be surrounded by 58b and stacked.

  The capacitance-type surface pressure measuring device 14 constitutes a capacitance-type sensor, for example, a plurality of insulators such as PI (polyimide), LCP (liquid crystal polymer), and PET (polyethylene terephthalate). A dielectric 50 is provided.

The conductive portion 52 is a rectangular conductive member that extends along the power generation surface direction of the power generation cell 16 and is, for example, a low-electricity material such as silver, silver alloy, gold, gold alloy, copper, copper alloy, aluminum, or aluminum alloy. It is composed of a resistance material (electric resistivity 2 × 10 ⁻⁷ Ωm or less), carbon paper, carbon cloth, conductive resin, or the like. The surface of the conductive portion 52 is subjected to a plating process using gold for prevention of oxidation or a gold alloy as necessary.

  A plurality of first groove portions 64a extending in the direction of the arrow B and arranged in the direction of the arrow C are formed on the surface 52a facing the first electrode 54 of the conductive portion 52. A plurality of second groove portions 64b extending in the direction of arrow C and arranged in the direction of arrow B are formed on the surface 52b of the conductive portion 52 facing the second electrode 56.

  The total depth of the first groove part 64 a and the second groove part 64 b is set to a dimension larger than the thickness of the conductive part 52. An opening 66 for disposing each dielectric 50 is provided at a portion where the first groove portion 64a and the second groove portion 64b intersect.

  The first electrode 54 is accommodated in the first groove portion 64 a of the conductive portion 52 and is formed in a long shape in the direction of arrow B. The first electrode 54 is made of, for example, copper or gold and has a thickness set to 0.1 mm or less. If necessary, it may be surrounded by an insulating film made of a polymer material (not shown).

  Similarly to the first electrode 54 described above, the second electrode 56 is accommodated in the second groove portion 64b of the conductive portion 52 and is formed in a long shape in the direction of arrow C (direction orthogonal to the direction of arrow B). . The second electrode 56 is made of, for example, copper or gold, and has a thickness set to 0.1 mm or less, and is surrounded by an insulating film made of a polymer material (not shown) as necessary.

  The insulating member 58a has a long shape that is accommodated in the first groove portion 64a and extends in the arrow B direction, and accommodates the first electrode 54 and the first shield member 60 in an insulated state. The insulating member 58b has a long shape that is accommodated in the second groove portion 64b and extends in the direction of the arrow C, and accommodates the second electrode 56 and the second shield member 62 in an insulated state. The insulating members 58a and 58b are made of, for example, PI (polyimide), LCP (liquid crystal polymer), PET (polyethylene terephthalate), or the like.

  The first shield member 60 and the second shield member 62 are elongated metal thin plates that are accommodated in the first groove portion 64a and the second groove portion 64b and extend in directions orthogonal to each other (arrow B direction and arrow C direction), For example, it is composed of Cu (copper), Al (aluminum), or the like. All the first shield members 60 and all the second shield members 62 are electrically connected and grounded to the ground of an amplifier 86 described later.

  As shown in FIG. 5, the dielectric 50 is arrange | positioned at each opening 66 of the electroconductive part 52, the 1st electrode 54 accommodated in the 1st groove part 64a, and the 2nd electrode 56 accommodated in the 2nd groove part 64b, Are arranged in a so-called grid pattern in a direction perpendicular to each other across the dielectric 50.

  As shown in FIGS. 5 and 6, the thickness t1 of the dielectric 50 in the stacking direction (arrow A direction) is set to be thicker (t1> t2) than the thickness t2 of the conductive portion 52 in the stacking direction. The Both surfaces of the dielectric 50 in the stacking direction are disposed so as to protrude outward from both surfaces of the conductive portion 52 in the stacking direction. The thickness t1 of the dielectric 50 in the stacking direction (arrow A direction) may be set to be thinner (t1 ≦ t2) than the thickness t2 of the conductive portion 52 in the stacking direction.

  As shown in FIG. 7, in the control device 68, the first circuit pattern 70 is provided at the end of the first electrode 54, while the second circuit pattern 72 is provided at the end of the second electrode 56. . The first circuit pattern 70 includes a wiring portion 74 connected to the end portion of each first electrode 54, and the wiring portion 74 is connected to the first connector 78 via an A / D converter 76. The second circuit pattern 72 includes a wiring unit 80 connected to the end of each second electrode 56, and the wiring unit 80 is connected to the second connector 84 via the A / D converter 82.

  The A / D converters 76 and 82 are arranged close to each other in the plane of the conductive portion 52 in order to avoid the influence of external noise. The first connector 78 and the second connector 84 are connected to the amplifier 86.

  In the first circuit pattern 70, the plurality of wiring portions 74 have the same length and the same surface area, while in the second circuit pattern 72, the plurality of wiring portions 80 have the same length and the same surface area. Is done.

  As shown in FIG. 8, the capacitance type surface pressure measuring device 14 includes a conductive sheet (for example, carbon paper, carbon cloth, etc.) 88 on both sides, and the first separator 24 and the second separator 26. It is pinched. The capacitance-type surface pressure measuring device 14 has substantially the same dimensions (including thickness) as the electrolyte membrane / electrode structure 22 shown in FIG. 3, and between the first and second separators 24, 26. By being sandwiched between the two, the same size and shape as the power generation cell 16 are formed.

  The capacitance type surface pressure measuring device 14 has a fuel gas on the surface of the first separator 24 on the side of the capacitance type surface pressure measuring device 14 so as not to be exposed to fuel gas or oxidant gas. The supply communication hole 32a and the fuel gas discharge communication hole 32b are circulated by a resin seal (not shown), while the surface of the second separator 26 on the capacitance type surface pressure measuring device 14 side is connected to the oxidant gas supply communication. The hole 28a and the oxidizing gas discharge communication hole 28b are circulated by a resin seal (not shown).

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

  First, as shown in FIG. 2, the fuel cell stack 12 includes a plurality of power generation cells 16 stacked in the direction of arrow A, and terminal plates 17a and 17b and insulating plates 18a and 18b interposed at both ends in the stacking direction. Thus, the end plates 20a and 20b are arranged. The end plates 20a and 20b are tightened in the stacking direction by a plurality of tightening bolts 21a, and an initial load is applied.

  For this reason, an initial load is applied to the fuel cell stack 12 in the stacking direction, and the dielectric 50 is compressed and deformed. Therefore, in the state where the thickness t1 of the dielectric 50 is the same as the thickness t2 of the conductive portion 52, the output sensitivity due to the thickness change of the dielectric 50 is improved, and the conductive portion 52 is The current can be surely passed in the stacking direction.

  Next, as shown in FIG. 1, the oxidant gas is supplied to the oxidant gas supply communication hole 28 a of the fuel cell stack 12, while the fuel gas is supplied to the fuel gas supply communication hole 32 a of the fuel cell stack 12. Is done. Further, the cooling medium is supplied to the cooling medium supply communication hole 30 a of the fuel cell stack 12.

  In the fuel cell stack 12, as shown in FIG. 3, the oxidant gas is introduced into the oxidant gas flow path 44 of the second 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 separator 24 from the fuel gas supply communication hole 32 a and moves along the anode side electrode 36 of the electrolyte membrane / electrode structure 22.

  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 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 then discharged to the end plate 20a.

  In addition, a cooling medium such as pure water or ethylene glycol is introduced into the cooling medium flow path 42 between the first separator 24 and the second separator 26 and then flows along the arrow B direction. The cooling medium cools the electrolyte membrane / electrode structure 22, then moves to the cooling medium discharge communication hole 30 b, and is discharged to the end plate 20 a for circulation.

  In this case, in this embodiment, as shown in FIGS. 4 to 6, the first electrode 54 and the second electrode 56 provided on both sides of the dielectric 50 are surrounded by the insulating members 58 a and 58 b, respectively. A first shield member 60 and a second shield member 62 are laminated. For this reason, the capacitance-type surface pressure measuring device 14 is not affected by noise from the outside, and an effect that stable measurement can be performed satisfactorily and reliably is obtained.

  As a result, it is possible to satisfactorily measure the surface pressure in the power generation surface covering the use load region of the fuel cell stack 12. Therefore, a normal current is not inhibited during power generation, and the surface pressure distribution in the fuel cell stack 12 can be measured with high accuracy and reliability.

  In the capacitance-type surface pressure measuring device 14, the first electrode 54 and the first shield member 60 are integrally accommodated in the insulating member 58 a while being insulated from each other. However, the present invention is not limited to this. It is not a thing. The same applies to the second electrode 56 and the second shield member 62.

  For example, as shown in FIG. 9, the first shield member 60 is surrounded by the insulating member 90a, and the first electrode 54 is surrounded by the insulating member 90b in a state where the first electrode 54 is laminated on the insulating member 90a. You may comprise.

  Further, as shown in FIG. 10, the first shield member 60 may be surrounded by the insulating member 92a, and the first electrode 54 may be surrounded by the insulating member 92b, and these may be laminated.

  Further, as shown in FIG. 11, the first shield member 60a is set to have a width dimension larger than that of the first electrode 54, and both end portions in the width direction of the first shield member 60a are bent toward the first electrode 54 side. . In a state where the first electrode 54 is covered with the first shield member 60 a, the first shield member 60 a and the first electrode 54 may be configured to be insulated from each other and surrounded by the insulating member 94.

  Furthermore, as shown in FIG. 12, the first shield member 60b is set to have a width dimension larger than that of the first electrode 54, and the first shield member 60b and the first electrode 54 are insulated from each other. Alternatively, the insulating member 96 may be surrounded.

DESCRIPTION OF SYMBOLS 10 ... Fuel cell system 12 ... Fuel cell stack 14 ... Capacitance type surface pressure measuring device 16 ... Power generation cell 22 ... Electrolyte membrane and electrode structure 24, 26 ... Separator 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 50 ... dielectric 52 ... conductive parts 54, 56 ... electrodes 58a, 58b, 90a, 90b, 92a, 92b, 94, 96 ... Insulating members 60, 60a, 60b, 62 ... Shield members 64a, 64b ... Groove portions 66 ... Openings 70, 72 ... Circuit patterns 74, 80 ... Wiring portions 76, 82 ... A / D converters 78, 84 ... Connectors 88 ... Conductive sheet

Claims (1)

A fuel cell stack having an electrolyte / electrode structure in which a pair of electrodes are disposed on both sides of the electrolyte, and a power generation cell having the electrolyte / electrode structure and a separator, and a fuel cell stack disposed in the fuel cell stack; A fuel cell system provided with a capacitance type surface pressure measuring device for measuring the surface pressure of the power generation cell,
The capacitance-type surface pressure measuring device includes a plurality of dielectrics provided in a power generation surface of the power generation cell,
A conductive portion that extends along the power generation surface direction of the power generation cell and that allows a current to flow between the dielectrics in the stacking direction;
A plurality of elongated first electrodes and a plurality of second electrodes extending in directions perpendicular to each other while sandwiching the dielectric from both sides in the stacking direction;
A plurality of elongated metal first shield members and a plurality of elongated first metal electrodes and a plurality of first electrodes and a plurality of second electrodes that are stacked with insulating sheets interposed therebetween and extend in directions orthogonal to each other. A metal second shield member;
With
Between the adjacent first electrodes and between the adjacent second electrodes, the conductive portions are respectively disposed,
The first circuit pattern connected to each first electrode has a plurality of first wiring portions connected to end portions of the first electrodes, and the plurality of first wiring portions have the same length and While set to the same surface area,
The second circuit pattern connected to each second electrode has a plurality of second wiring portions connected to the end portions of the second electrodes, and the plurality of second wiring portions have the same length as each other and A fuel cell system having the same surface area.

Images