JP2008027805A - Fuel cell stack and water content measuring device of fuel cell stack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell stack and a water content measuring device capable of measuring the water content in each fuel cell unit of the fuel cell stack. <P>SOLUTION: The fuel cell stack generating electric power by the chemical reaction of hydrogen and oxygen includes a plurality of fuel cell units stacked; a plurality of separators formed between the fuel cell units and in fuel cell units of both ends; end plates formed in the separators of both ends; and a plurality of electrodes, in which the surface is covered with an insulating film, formed in the plurality of separators, and whose one end is drawn out to the outside of the fuel cell stack. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel cell stack that generates power by chemically reacting hydrogen and oxygen, and in particular, it is possible to measure the amount of water that greatly affects the characteristics of the fuel cell for each fuel cell of the fuel cell stack. The present invention relates to a fuel cell stack and a water content measuring device.

  Prior art documents related to a fuel cell that generates power by chemically reacting hydrogen and oxygen are as follows.

JP 2003-051318 A JP 2003-036875 A JP 2003-297408 A JP 2005-222854 A

  FIG. 5 is a block diagram showing an example of a conventional fuel cell system. In FIG. 5, 1 is an electrolyte membrane, 2 and 3 are catalyst layers and diffusion layers. A catalyst layer / diffusion layer 2 and a catalyst layer / diffusion layer 3 are formed on both surfaces of the electrolyte membrane 1, respectively.

  A fuel gas (for example, hydrogen) is supplied to the catalyst layer / diffusion layer 2 as indicated by “FG01” in FIG. 5, and an oxidizing gas (for example, oxygen or air) is indicated by “OG01” in FIG. It is supplied to the catalyst layer / diffusion layer 3.

Here, the operation of the conventional example shown in FIG. 5 will be described. On the catalyst layer / diffusion layer 2 side (anode side), hydrogen becomes hydrogen ions (H ⁺ ) and releases electrons (e ⁻ ), while on the catalyst layer / diffusion layer 3 side (cathode side), it propagates through the electrolyte membrane 1. The generated hydrogen ions (H ⁺ ) and oxygen atoms react with electrons (e ⁻ ) to generate water (H ₂ O).

At this time, electrons generated on the catalyst layer / diffusion layer 2 side (anode side) by connecting external loads between the catalyst layer / diffusion layer 2 (anode side) and the catalyst layer / diffusion layer 3 (cathode side) ( e ⁻ ) can be taken out, in other words, direct current can be taken out.

  6 and 7 are cross-sectional views showing an example of a more specific conventional fuel cell. 6 is a cross-sectional view in a plane perpendicular to the electrolyte membrane of the fuel cell, and FIG. 7 is a cross-sectional view in a plane parallel to the gas flow path in the fuel cell.

  6, 4 is an electrolyte membrane, 5 is a catalyst layer / diffusion layer on the anode side, 6 is a catalyst layer / diffusion layer on the cathode side, and 7 is a gas flow path of fuel gas (for example, hydrogen) formed on the anode side. , 8 is a gas flow path of oxidizing gas (oxygen, air, etc.) formed on the cathode side, 9 is a conductive separator formed on the anode side, and 10 is a conductive separator formed on the cathode side. is there.

  A catalyst layer / diffusion layer 5 and a catalyst layer / diffusion layer 6 are formed on both surfaces of the electrolyte membrane 4, respectively. Further, a gas flow path 7 of a fuel gas (for example, hydrogen) is formed on the catalyst layer / diffusion layer 5, and an oxidizing gas (for example, oxygen or air) is formed on the catalyst layer / diffusion layer 6. A gas flow path 8 is formed.

  For example, the gas flow path 7 and the gas flow path 8 are formed so as to meander over the catalyst layer / diffusion layer 5 and the catalyst layer / diffusion layer 6 as indicated by “GT11” in FIG.

  Further, a separator 9 is formed on the catalyst layer / diffusion layer 5 and the gas flow path 7 where the gas flow path 7 is not formed, and the catalyst layer / diffusion layer 6 and the gas flow where the gas flow path 8 is not formed. A separator 10 is formed on the path 8.

  Here, the operation of the conventional example shown in FIGS. 6 and 7 will be described. A fuel gas (for example, hydrogen) is supplied to the gas channel 7, and an oxidizing gas (for example, oxygen or air) is supplied to the gas channel 8. For example, each gas is supplied from the supply port indicated by “IN11” in FIG. 7, and unreacted gas is discharged from the exhaust port indicated by “OT11” in FIG.

In the catalyst layer / diffusion layer 5 on the anode side, hydrogen becomes hydrogen ions (H ⁺ ) and emits electrons (e ⁻ ), while hydrogen that has propagated through the electrolyte membrane 4 on the catalyst layer / diffusion layer 6 side on the cathode side. Ions (H ⁺ ) and oxygen atoms react with electrons (e ⁻ ) to generate water (H ₂ O).

At this time, by connecting an external load between the catalyst layer / diffusion layer 5 on the anode side and the catalyst layer / diffusion layer 6 on the cathode side (specifically, the separator 9 and the separator 10), the catalyst layer on the anode side It is possible to take out electrons (e ⁻ ) generated in the diffusion layer 5, in other words, to take out direct current.

  In addition, a stack of a plurality of such individual fuel cells (hereinafter referred to as fuel cell) (electrically connected in series) is called a fuel cell stack, and the voltage that can be taken out by using the fuel cell stack is increased. can do.

However, the water content of water (H ₂ O) generated by the reaction of hydrogen ions (H ⁺ ) and oxygen atoms that have propagated through the electrolyte membrane 4 with electrons (e ⁻ ) greatly affects the characteristics of the fuel cell. However, “Patent Document 3” and “Patent Document 4” describe a fuel cell provided with means for measuring the moisture content inside the fuel cell.

  Specifically, in “Patent Document 3”, as an example of measuring the moisture content, an example in which the moisture content is obtained using the internal resistance value obtained from the current and voltage characteristics of the fuel cell stack as the electrical conductivity of the solid electrolyte membrane. “Patent Document 4” describes an example in which a change in the amount of water inside the fuel cell stack is calculated from the current value of the fuel cell stack, the supply amount of the oxidizing gas, and the discharge amount of the oxidizing gas.

However, in practice, it is known that the moisture distribution between the fuel cells of the fuel cell stack is not uniform, and the moisture is partially distributed. "Patent Document 3" and "Patent Document 4" In the conventional example described in (2), the moisture content of the entire fuel cell stack can be measured, but the moisture content of each fuel cell constituting the fuel cell stack cannot be measured. there were.
Therefore, the problem to be solved by the present invention is to realize a fuel cell stack and a water content measuring device capable of measuring the water content in units of fuel cells of the fuel cell stack.

In order to achieve such a problem, the invention according to claim 1 of the present invention is:
In a fuel cell stack that generates electricity by chemically reacting hydrogen and oxygen,
A plurality of stacked fuel cells, a plurality of separators formed between the fuel cells and the fuel cells at both ends, an end plate formed at each of the separators at both ends, and a plurality of the separators The surface of the fuel cell stack is formed with a plurality of electrodes, one end of which is drawn out of the fuel cell stack, so that the water content can be measured in units of fuel cells of the fuel cell stack. Become.

The invention according to claim 2
In the fuel cell stack according to claim 1,
The fuel battery cell is
An electrolyte membrane; first and second catalyst layers / diffusion layers formed on both surfaces of the electrolyte membrane; a gas flow path for fuel gas formed in the first catalyst layer / diffusion layer; By comprising the gas flow path of the oxidizing gas formed in the catalyst layer / diffusion layer, it becomes possible to measure the water content in units of fuel cells of the fuel cell stack.

The invention described in claim 3
In a moisture measuring device for a fuel cell stack that generates electricity by chemically reacting hydrogen and oxygen,
A plurality of stacked fuel cells, a plurality of separators formed between the fuel cells and the fuel cells at both ends, an end plate formed at each of the separators at both ends, and a plurality of the separators A plurality of electrodes each having a surface covered with an insulating film and having one end drawn out of the fuel cell stack, and the electrostatic capacitance of the insulating film measured in advance by sequentially measuring the capacitance between the electrodes. By providing the capacitance measuring device that obtains the value corrected by the capacity, it becomes possible to measure the water content in units of fuel cells of the fuel cell stack.

The invention according to claim 4
In a moisture measuring device for a fuel cell stack that generates electricity by chemically reacting hydrogen and oxygen,
A plurality of stacked fuel cells, a plurality of separators formed between the fuel cells and the fuel cells at both ends, an end plate formed at each of the separators at both ends, and a plurality of the separators A plurality of electrodes each having a surface covered with an insulating film and having one end drawn out of the fuel cell stack and the electrostatic capacitance of the insulating film measured in advance by simultaneously measuring the capacitance between the electrodes. By providing the capacitance measuring device that corrects by the capacity and calculates the difference between the correction values, it becomes possible to measure the water content in units of fuel cells of the fuel cell stack.

The invention according to claim 5
In the water content measuring apparatus for a fuel cell stack according to claim 3 or claim 4,
The fuel battery cell is
An electrolyte membrane; first and second catalyst layers / diffusion layers formed on both surfaces of the electrolyte membrane; a gas flow path for fuel gas formed in the first catalyst layer / diffusion layer; By comprising the gas flow path of the oxidizing gas formed in the catalyst layer / diffusion layer, it becomes possible to measure the water content in units of fuel cells of the fuel cell stack.

The present invention has the following effects.
According to the first, second, third and fifth aspects of the present invention, an electrode whose surface is covered with an insulating film is formed in the separator of the fuel cell stack, and one end of the electrode is drawn out of the fuel cell stack. It is possible to measure the amount of water in units of fuel cells of the fuel cell stack by sequentially measuring the capacitance between the electrodes and obtaining a value corrected with the capacitance of the insulating film measured in advance. become.

  According to the first, second, fourth and fifth aspects of the present invention, an electrode whose surface is covered with an insulating film is formed in the separator of the fuel cell stack, and one end of the electrode is placed outside the fuel cell stack. At the same time, the capacitance between the electrodes is simultaneously measured and corrected with the previously measured capacitance of the insulating film, and by calculating the difference between the correction values, moisture in each fuel cell of the fuel cell stack is calculated. It becomes possible to measure the quantity.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing an embodiment of a fuel cell stack according to the present invention. FIG. 1 is a cross-sectional view in a plane perpendicular to the electrolyte membrane of the fuel cell stack.

  In FIG. 1, 11, 14 and 17 are electrolyte membranes, 12, 15 and 18 are cathode-side catalyst layers / diffusion layers, 13, 16 and 19 are anode-side catalyst layers / diffusion layers, and 20, 22 and 24 are cathodes. Gas flow paths for oxidizing gas (oxygen, air, etc.) formed on the side, 21, 23 and 25 are gas flow paths for fuel gas (for example, hydrogen, etc.) formed on the anode side, 26, 27, 28 and 29 Is an electrically conductive separator, 30, 31, 32 and 33 are insulating films, 34, 35, 36 and 37 are electrodes, 38 and 39 are provided at both ends of each cell, and the positive and negative electrodes of the fuel cell stack. It is an end plate which functions as an electrode.

  11, 12, 13, 20, 21, 26, and 27 are first fuel cells, 14, 15, 16, 22, 23, 27, and 28 are second fuel cells, 17, 18, 19, 24, 25, 28 and 29 constitute a third fuel cell, respectively.

  The catalyst layer / diffusion layer 12 and the catalyst layer / diffusion layer 13 are formed on both surfaces of the electrolyte membrane 11, and the catalyst layer / diffusion layer 15 and the catalyst layer / diffusion layer 16 are formed on both surfaces of the electrolyte membrane 17. A catalyst layer / diffusion layer 18 and a catalyst layer / diffusion layer 19 are respectively formed.

  A gas flow path 20 for oxidizing gas (for example, oxygen or air) is formed on the catalyst layer / diffusion layer 12, and a fuel gas (for example, hydrogen) is formed on the catalyst layer / diffusion layer 13. A gas flow path 21 is formed.

  Similarly, a gas flow path 22 of an oxidizing gas (for example, oxygen or air) is formed on the catalyst layer / diffusion layer 15, and a fuel gas (for example, hydrogen) is formed on the catalyst layer / diffusion layer 16. Gas flow path 23 is formed.

  Further, a gas flow path 24 of an oxidizing gas (for example, oxygen or air) is formed on the catalyst layer / diffusion layer 18, and a fuel gas (for example, hydrogen) is formed on the catalyst layer / diffusion layer 19. A gas flow path 25 is formed.

  For example, the gas flow paths 20, 21, 22, 23, 24 and the gas flow path 25 are formed so as to meander over the respective catalyst layers / diffusion layers as indicated by “GT 11” in FIG. 7.

  The separator 26 is formed on the gas flow path 20 and the catalyst layer / diffusion layer 12 where the gas flow path 20 is not formed, and the end plate 38 is formed on the separator 26.

  Similarly, a separator 29 is formed on the gas flow path 25 and the catalyst layer / diffusion layer 19 where the gas flow path 25 is not formed, and an end plate 39 is formed on the separator 29.

  A separator is provided between the catalyst layer / diffusion layer 13 in which the gas channel 21 and the gas channel 21 are not formed and the catalyst layer / diffusion layer 15 in which the gas channel 22 and the gas channel 22 are not formed. 27 between the catalyst layer / diffusion layer 16 in which the gas channel 23 and the gas channel 23 are not formed and the catalyst layer / diffusion layer 18 in which the gas channel 24 and the gas channel 24 are not formed. Is formed with a separator 28.

  Finally, an electrode 34 whose surface is covered with an insulating film 30 is formed in the separator 26, and one end of the electrode 34 is drawn out of the fuel cell stack.

  Similarly, an electrode 35 whose surface is covered with an insulating film 31 is formed in the separator 27, an electrode 36 whose surface is covered with an insulating film 32 is formed in the separator 28, and a surface which is covered with an insulating film 33 is formed in the separator 29. The covered electrodes 37 are formed, and the electrodes 35 and 36 and one end of the electrode 37 are drawn out of the fuel cell stack.

  Here, the operation of the embodiment shown in FIG. 1 will be described with reference to FIGS. FIG. 2 is a circuit diagram showing an electrical equivalent circuit viewed from the electrodes 34 to 37, and FIGS. 3 and 4 are explanatory diagrams for explaining a capacitance measuring method using the electrodes 34 to 37. FIG.

  In the first fuel cell, an oxidizing gas (for example, oxygen or air) is supplied to the gas passage 20, and a fuel gas (for example, hydrogen) is supplied to the gas passage 21. For example, each gas is supplied from the supply port indicated by “IN11” in FIG. 7, and unreacted gas is discharged from the exhaust port indicated by “OT11” in FIG.

In the catalyst layer / diffusion layer 13 on the anode side, hydrogen becomes hydrogen ions (H ⁺ ) and emits electrons (e ⁻ ), while hydrogen that has propagated through the electrolyte membrane 11 on the catalyst layer / diffusion layer 12 side on the cathode side. Ions (H ⁺ ) and oxygen atoms react with electrons (e ⁻ ) to generate water (H ₂ O).

At this time, the catalyst layer on the anode side is connected by connecting external loads between the catalyst layer / diffusion layer 13 on the anode side and the catalyst layer / diffusion layer 12 on the cathode side (specifically, the separator 27 and the separator 26). It is possible to extract electrons (e ⁻ ) generated in the diffusion layer 13, in other words, to extract a direct current.

  Similarly, in the second fuel cell, an oxidizing gas (for example, oxygen or air) is supplied to the gas passage 22, and a fuel gas (for example, hydrogen) is supplied to the gas passage 23. In the fuel cell of No. 3, an oxidizing gas (for example, oxygen or air) is supplied to the gas channel 24, and a fuel gas (for example, hydrogen) is supplied to the gas channel 25. For example, each gas is supplied from the supply port indicated by “IN11” in FIG. 7, and unreacted gas is discharged from the exhaust port indicated by “OT11” in FIG.

  Since the above-described chemical reaction in the first fuel cell occurs in both the second fuel cell and the third fuel cell, the catalyst layer / diffusion layer 19 on the anode side and the catalyst layer / diffusion layer 12 on the cathode side. (Specifically, by connecting an external load between the end plate 39 and the end plate 38, a direct current is taken out from the fuel cell stack (the first to third fuel cells are connected in series). It becomes possible.

  In such an operating state of the fuel cell, the electrolyte membrane between the electrodes 34, 35, 36 and the electrode 37 is measured by measuring the capacitance with the capacitance measuring device using the electrodes 34, 35, 36 and the electrode 37. The moisture content of the catalyst layer / diffusion layer and gas flow path can be measured as capacitance.

  That is, an electrical equivalent circuit viewed from the electrodes 34, 35, 36 and the electrode 37 is as shown in FIG.

  In FIG. 2, “ED21”, “ED22”, “ED23”, and “ED24” indicate electrodes 34, 35, 36, and 37. In FIG. 2, “CP21”, “CP22”, “CP23”, and “CP24” are insulated. The capacitance of the films 30, 31, 32 and 33.

  Further, “CP25” in FIG. 2 is a capacitance of the electrolyte membrane 11 (corresponding to the first fuel cell). Similarly, “CP26” in FIG. 2 is the capacitance of the electrolyte membrane 14 (corresponding to the second fuel cell), and “CP27” in FIG. 2 is the electrolyte membrane 17 (corresponding to the third fuel cell). The capacitance of

  That is, in the equivalent circuit shown in FIG. 2, the electrode indicated by “ED21” in FIG. 2 is connected to one end of the capacitance “CP21”, and the other end of the capacitance “CP21” is one end of the capacitance “CP25”. Connected to. 2 is connected to one end of the capacitance “CP22”, and the other end of the capacitance “CP22” is connected to the other end of the capacitance “CP25” and the capacitance “CP26”. Are connected to one end of each.

  The electrode indicated by “ED23” in FIG. 2 is connected to one end of the capacitance “CP23”, and the other end of the capacitance “CP23” is the other end of the capacitance “CP26” and one end of the capacitance “CP27”. Connected to each. Finally, the electrode indicated by “ED24” in FIG. 2 is connected to the other end of the capacitance “CP27”.

  Here, a method for measuring the capacitance of each fuel cell will be described. In FIG. 3, “CP21”, “CP22”, “CP23”, “CP24”, “CP25”, “CP26” and “CP27” are assigned the same reference numerals as in FIG. It is a capacitance measuring device that measures the same.

  In addition, the switches indicated by “SW31”, “SW32”, “SW33”, and “SW34” in FIG. 3 appropriately select the electrodes 34, 35, 36, and the electrode 37 and connect them to the input terminal of the capacitance measuring device 41. .

  The switch indicated by “SW31” in FIG. 3 selects one end (electrode 34) of the capacitance “CP21”, and the switch indicated by “SW32” in FIG. 3 selects one end (electrode 35) of the capacitance “CP22”. In this case, the capacitance measuring device 41 measures the capacitance value in which the capacitances “CP21”, “CP25”, and “CP22” are connected in series.

  Then, the capacitance “CP21” or “CP22” of the insulating film is measured in advance (for example, the capacitance between the electrode and the separator on which the electrode is formed is measured to obtain the capacitance of the insulating film. The value obtained by subtracting the capacitance of the insulating film measured in advance from the capacitance value measured by the capacitance measuring device 41 is used as the capacitance of the first fuel cell. It is assumed that “CP25”.

  Similarly, one end (electrode 35) of the capacitance “CP22” is selected by the switch indicated by “SW32” in FIG. 3, and one end (electrode 36) of the capacitance “CP23” is selected by the switch indicated by “SW33” in FIG. ) Is selected, the capacitance measuring device 41 measures the capacitance value in which the capacitances “CP22”, “CP26” and “CP23” are connected in series.

  Then, the capacitance “CP22” or “CP23” of the insulating film is measured in advance (for example, the capacitance between the electrode and the separator on which the electrode is formed is measured to obtain the capacitance of the insulating film. The value obtained by subtracting the capacitance of the insulating film measured in advance from the capacitance value measured by the capacitance measuring device 41 is used as the capacitance of the second fuel cell. It is assumed that “CP26”.

  Finally, one end (electrode 36) of the capacitance “CP23” is selected by a switch indicated by “SW33” in FIG. 3, and one end (electrode 37) of the capacitance “CP24” is selected by a switch indicated by “SW34” in FIG. ) Is selected, the capacitance measuring device 41 measures the capacitance value in which the capacitances “CP23”, “CP27”, and “CP24” are connected in series.

  Then, the capacitance “CP23” or “CP24” of the insulating film is measured in advance (for example, the capacitance between the electrode and the separator on which the electrode is formed is measured to obtain the capacitance of the insulating film. The value obtained by subtracting the capacitance of the insulating film measured in advance from the capacitance value measured by the capacitance measuring device 41 is used as the capacitance of the third fuel cell. It is assumed that “CP27”.

  As a result, an electrode whose surface is covered with an insulating film is formed in the separator of the fuel cell stack, and one end of the electrode is drawn out of the fuel cell stack, and the capacitance between the electrodes is sequentially measured in advance. By obtaining a value corrected by the capacitance of the insulating film, the water content can be measured in units of fuel cells of the fuel cell stack.

  Here, another method for measuring the capacitance of each fuel cell will be described. In FIG. 4, “ED21”, “ED22”, “ED23”, “ED24”, “CP21”, “CP22”, “CP23”, “CP24”, “CP25”, “CP26” and “CP27” are the same as those in FIG. The same reference numerals are attached, and 42, 43 and 44 are capacitance measuring devices for measuring capacitance (corresponding to the amount of water).

  A capacitance measuring device 42 is connected between the electrodes indicated by “ED21” and “ED22” in FIG. 4, and a capacitance measuring device 43 is connected between the electrodes indicated by “ED21” and “ED23” in FIG. Is done. Further, a capacitance measuring device 44 is connected between the electrodes indicated by “ED21” and “ED24” in FIG.

  Capacitance measuring devices 42, 43 and 44 simultaneously measure the capacitance between the electrodes. Since the capacitance measuring device 42 measures the capacitance between the electrodes indicated by “ED21” and “ED22” in FIG. 4, the capacitances “CP21”, “CP25” and “CP22” are connected in series. The capacitance value is measured.

  Further, since the capacitance measuring device 43 measures the capacitance between the electrodes indicated by “ED21” and “ED23” in FIG. 4, the capacitances “CP21”, “CP25”, “CP26” and “CP23” are measured. Are measured in series.

  Further, since the capacitance measuring device 44 measures the capacitance between the electrodes indicated by “ED21” and “ED24” in FIG. 4, the capacitances “CP21”, “CP25”, “CP26”, “CP27”. And the capacitance value in which “CP24” is connected in series is measured.

  Then, the capacitances “CP21” to “CP24” of the insulating film are measured in advance (for example, the capacitance between the electrode and the separator on which the electrode is formed is measured to obtain the capacitance of the insulating film. And subtracting the capacitance of the insulating film measured in advance from the capacitance values measured by the capacitance measuring devices 42 to 44 and calculating the difference between the correction values. The capacitances “CP25”, “CP26” and “CP27” of the first, second and third fuel cells can be separated.

  For example, the correction value in the capacitance measuring device 43 (capacitance value in which capacitances “CP25” and “CP26” are connected in series) and the correction value in the capacitance measuring device 42 (capacitance “CP25”). The electrostatic capacity “CP26” of the second fuel cell is separated by calculating the difference from the electrostatic capacity value of the second fuel cell.

  Similarly, for example, correction values in the capacitance measuring device 44 (capacitance values in which the capacitances “CP25”, “CP26”, and “CP27” are connected in series) and correction values in the capacitance measuring device 43 are used. The capacitance “CP27” of the third fuel cell is separated by calculating the difference from (capacitance value in which the capacitances “CP25” and “CP26” are connected in series).

  As a result, an electrode whose surface is covered with an insulating film is formed in the separator of the fuel cell stack, and one end of the electrode is drawn out of the fuel cell stack, and the capacitance between the electrodes is simultaneously measured and measured in advance. It is possible to measure the amount of water in units of fuel cells of the fuel cell stack by correcting with the capacitance of the insulating film and calculating the difference between the correction values.

  In the embodiment shown in FIG. 1, a fuel cell stack in which three fuel cells are stacked is configured for simplicity of description. Of course, a fuel cell stack is configured by stacking a plurality of fuel cells. It doesn't matter.

  In this case, an electrode whose surface is covered with an insulating film is formed in the separator formed between both ends of the fuel cell stack or between each fuel cell, and one end of the electrode is drawn out of the fuel cell stack. Thus, the moisture content can be measured in units of fuel cells of the fuel cell stack in the same manner as in the description of the embodiment shown in FIG.

  Further, in the description of the embodiment shown in FIG. 1, it is exemplified that each gas flow path is formed so as to meander on the catalyst layer / diffusion layer. Of course, the structure of the gas flow path is this structure. It is not limited to.

  In the description of the embodiment shown in FIG. 1, each electrode is formed in the separator in a direction intersecting the gas flow path. However, the present invention is not limited to this and is parallel to the gas flow path. It may be in the direction or in other directions.

  In addition, in the capacitance measuring method shown in FIGS. 3 and 4, correction is performed by subtracting the capacitance of the insulating film measured in advance from the capacitance value measured by the capacitance measuring device. Although described, it is of course possible to set the capacitance of the insulating film that has been measured in advance in the capacitance measuring device, and to perform correction calculation in the capacitance measuring device.

  In the capacitance measuring method shown in FIG. 4, the capacitance between the electrodes is simultaneously measured using a plurality of capacitance measuring devices for simplicity of explanation. You may measure the electrostatic capacitance between electrodes simultaneously with one electrostatic capacitance measuring apparatus which has a terminal.

  In addition, in the capacitance measuring method shown in FIG. 4, it is described that the difference between the correction values is calculated to separate the capacitance of each fuel cell, but the correction value of each capacitance measuring device is Of course, the difference calculation may be performed by any one of the capacitance measurement devices, one capacitance measurement device having a plurality of input terminals, or a separate calculation control device.

It is sectional drawing which shows one Example of the fuel cell which concerns on this invention. It is a circuit diagram which shows the electrical equivalent circuit seen from the electrode. It is explanatory drawing explaining the measuring method of the electrostatic capacitance using an electrode. It is explanatory drawing explaining the measuring method of the electrostatic capacitance using an electrode. It is a block diagram showing an example of a conventional fuel cell system. It is sectional drawing in a surface perpendicular | vertical with respect to the electrolyte membrane of a fuel cell. It is sectional drawing in the surface parallel to the gas flow path in a fuel cell.

Explanation of symbols

1, 4, 11, 14, 17 Electrolyte membrane 2, 3, 5, 6, 12, 13, 15, 16, 18, 19 Catalyst layer / diffusion layer 7, 8, 20, 21, 22, 23, 24, 25 Gas flow path 9, 10, 26, 27, 28, 29 Separator 30, 31, 32, 33 Insulating film 34, 35, 36, 37 Electrode 38, 39 End plate

Claims (5)

In a fuel cell stack that generates electricity by chemically reacting hydrogen and oxygen,
A plurality of stacked fuel cells; and
A plurality of separators respectively formed between the fuel cells and the fuel cells at both ends;
End plates respectively formed on the separators at both ends;
A fuel cell stack, comprising: a plurality of electrodes each having a surface covered with an insulating film and having one end drawn out of the fuel cell stack. The fuel battery cell is
An electrolyte membrane;
First and second catalyst layers / diffusion layers formed on both surfaces of the electrolyte membrane;
A gas flow path of fuel gas formed in the first catalyst layer / diffusion layer;
2. The fuel cell stack according to claim 1, comprising a gas flow path of an oxidizing gas formed in the second catalyst layer / diffusion layer. In a moisture measuring device for a fuel cell stack that generates electricity by chemically reacting hydrogen and oxygen,
A plurality of stacked fuel cells; and
A plurality of separators respectively formed between the fuel cells and in the fuel cells at both ends;
End plates respectively formed on the separators at both ends;
A plurality of electrodes each having a surface covered with an insulating film formed in each of the separators and having one end drawn out of the fuel cell stack;
A moisture content measuring device comprising: a capacitance measuring device that sequentially measures the capacitance between the electrodes and obtains a value corrected by the capacitance of the insulating film measured in advance. In a moisture measuring device for a fuel cell stack that generates electricity by chemically reacting hydrogen and oxygen,
A plurality of stacked fuel cells; and
A plurality of separators respectively formed between the fuel cells and in the fuel cells at both ends;
End plates respectively formed on the separators at both ends;
A plurality of electrodes each having a surface covered with an insulating film formed in each of the separators and having one end drawn out of the fuel cell stack;
Moisture content characterized by comprising a capacitance measuring device that simultaneously measures the capacitance between the electrodes, corrects it with the capacitance of the insulating film measured in advance, and calculates the difference between the correction values measuring device. The fuel battery cell is
An electrolyte membrane;
First and second catalyst layers / diffusion layers formed on both surfaces of the electrolyte membrane;
A gas flow path of fuel gas formed in the first catalyst layer / diffusion layer;
The moisture content measuring apparatus according to claim 3 or 4, comprising a gas flow path of an oxidizing gas formed in the second catalyst layer / diffusion layer.

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