JP5474839B2 - Fuel cell current density distribution measuring device - Google Patents

Description

  The present invention relates to a current density distribution measuring device for a fuel cell in which an electrolyte / electrode structure in which an anode side electrode and a cathode side electrode are provided on both sides of an electrolyte, and a separator are laminated.

  For example, a polymer electrolyte fuel cell employs an electrolyte membrane (electrolyte) made of a polymer ion exchange membrane. A fuel cell is configured by sandwiching an electrolyte membrane / electrode structure (MEA) in which an anode side electrode and a cathode side electrode are disposed on both sides of the electrolyte membrane with a separator.

  In the fuel cell described above, a method of measuring a current density distribution is employed in order to detect a failure, perform a quality inspection, or detect a flooding. For example, a control device for a fuel cell system disclosed in Patent Document 1 is known.

  The fuel cell system includes a plurality of fuel cells stacked and at least one current density sensor that measures a current density distribution in a plane perpendicular to the stacking direction between the stacked fuel cells. It has a stack.

  The control device observes the internal state of the fuel cell stack based on the measured current density distribution, and operates the fluid supplied to the fuel cell stack in accordance with the observed internal state. Controlling the output current distribution in the battery stack to be uniform, the operation of the fluid is at least one of a flow rate of fuel gas, a flow rate of oxidant gas, a flow rate of cooling medium, and a humidification amount of the oxidant gas. It is characterized by including one operation.

  In the fuel cell system, it is necessary to monitor the power generation status of each fuel cell during operation and detect whether the fuel cell is generating power normally. For this reason, as a monitoring device, for example, a method of incorporating a potential sensor into a fuel cell system and detecting the potential of the anode or cathode of each fuel cell is employed.

JP 2006-318784 A

  However, in Patent Document 1 described above, only the current density distribution is measured, and the electrode potential of the fuel cell cannot be measured. Therefore, it is difficult to grasp the reaction state inside the fuel cell in detail, and there is a problem that the fuel cell cannot be efficiently controlled.

  The present invention solves this type of problem, and an object thereof is to provide a fuel cell current density distribution measuring device capable of easily and accurately measuring the current density distribution on the power generation surface of the fuel cell. To do.

  The present invention relates to a current density distribution measuring device for a fuel cell in which an electrolyte / electrode structure in which an anode side electrode and a cathode side electrode are provided on both sides of an electrolyte, and a separator are laminated.

  In this current density distribution measuring apparatus, a region corresponding to the power generation surface region of the electrolyte / electrode structure is divided into a plurality of regions, and a plurality of planar rectangular electrode segments each forming a pair, and a plurality of one poles A pair of insulating sheets disposed between the electrode segment and the plurality of electrode segments as the other pole, and a plurality of thin film resistors disposed between the pair of insulating sheets corresponding to each electrode segment With body.

On one surface of the thin film resistor, there is provided a first electrode portion that penetrates one insulating sheet and is connected to one electrode segment, and the other surface of the thin film resistor has the other A second electrode portion that penetrates the insulating sheet and is connected to the other electrode segment is provided. The first electrode portion and the second electrode portion are arranged at opposite positions or diagonal positions of the electrode segment, and the first wiring pattern and the second wiring for voltage acquisition are provided on the thin film resistor. Each one end of the pattern is connected, while the other end of each of the first wiring pattern and the second wiring pattern is connected to a connector, and the first wiring pattern connected to each thin film resistor and the The total length of the second wiring patterns is set to the same length .

  In this current density distribution measuring apparatus, it is preferable that a spacer member having the same thickness as the thin film resistor is interposed between the pair of insulating sheets adjacent to the thin film resistor.

  Furthermore, in this current density distribution measuring apparatus, it is preferable that the first wiring pattern and the second wiring pattern are set to have the same cross-sectional area.

  According to the present invention, a plurality of electrode segments obtained by dividing the power generation surface region of the electrolyte / electrode structure into a plurality of regions are provided, and a plurality of thin film resistors are disposed corresponding to each electrode segment. . For this reason, the distribution of the current density in each region in the power generation surface can be measured only by measuring the voltage generated at both ends of the thin film resistor.

  In addition, the first electrode portion and the second electrode portion provided on both surfaces of the thin film resistor are arranged at opposite side positions or diagonal positions of the electrode segment. Therefore, the resistance length can be increased, and the resistance value can be maximized within a limited area, which is efficient.

It is a principal part disassembled perspective view of the fuel cell in which the measuring device concerning a 1st embodiment of the present invention is built. It is principal part cross-sectional explanatory drawing of the said measuring device. It is a schematic explanatory drawing of shunt resistance. It is a schematic explanatory drawing of other shunt resistance. It is a schematic explanatory drawing of another shunt resistance. It is a schematic explanatory drawing of another shunt resistance. It is partial front explanatory drawing of the said measuring device. It is principle explanatory drawing of the said measuring device arrange | positioned between fuel cells. It is principal part cross-sectional explanatory drawing of the measuring device which concerns on the 2nd Embodiment of this invention. It is a schematic explanatory drawing of shunt resistance and a spacer. It is a schematic explanatory drawing of another shunt resistance and another spacer. It is a schematic explanatory drawing of another shunt resistance and another spacer. It is a schematic explanatory drawing of another shunt resistance and another spacer. It is principle explanatory drawing of another measuring device arrange | positioned between separators.

  As shown in FIG. 1, a fuel cell 12 in which a measuring device 10 according to an embodiment of the present invention is incorporated includes an electrolyte membrane / electrode structure (electrolyte / electrode structure) 14 and the electrolyte membrane / electrode structure 14. First and second separators 16 and 18 are sandwiched. The 1st and 2nd separators 16 and 18 are comprised by a metal separator or a carbon separator, for example.

  One end edge (upper end edge) of the fuel cell 12 in the direction of arrow C (vertical direction in FIG. 1) communicates with each other in the direction of arrow A, which is the stacking direction, and an oxidant gas such as an oxygen-containing gas An oxidant gas supply communication hole 20a for supplying and a fuel gas supply communication hole 22a for supplying a fuel gas, for example, a hydrogen-containing gas, are arranged in an arrow B direction (horizontal direction).

  The other end edge (lower end edge) of the fuel cell 12 in the direction of arrow C communicates with each other in the direction of arrow A, and the fuel gas discharge communication hole 22b for discharging the fuel gas and the oxidant gas are discharged. The oxidant gas discharge communication holes 20b are arranged in the direction of the arrow B.

  A cooling medium supply communication hole 24a for supplying a cooling medium is provided at one end edge of the fuel cell 12 in the arrow B direction, and a cooling medium is provided at the other end edge of the fuel cell 12 in the arrow B direction. Is provided with a cooling medium discharge communication hole 24b.

  The electrolyte membrane / electrode structure 14 includes, for example, a solid polymer electrolyte membrane 26 in which a perfluorosulfonic acid thin film is impregnated with water, and a cathode side electrode 28 and an anode side electrode 30 that sandwich the solid polymer electrolyte membrane 26. With.

  The cathode side electrode 28 and the anode side electrode 30 have an electrode catalyst layer bonded to both surfaces of the solid polymer electrolyte membrane 26 and a gas diffusion layer made of carbon paper or the like disposed on the electrode catalyst layer. The electrode catalyst layer is formed by uniformly applying porous carbon particles carrying a platinum alloy on both surfaces of the solid polymer electrolyte membrane 26.

  An oxidant gas flow path 32 is provided on the surface 16 a of the first separator 16 facing the electrolyte membrane / electrode structure 14. The oxidant gas flow channel 32 has a plurality of flow channel grooves extending in the direction of arrow C, and communicates with the oxidant gas supply communication hole 20a and the oxidant gas discharge communication hole 20b. A cooling medium flow path 34 is provided between the surface 16 b of the first separator 16 and the surface 18 b of the second separator 18.

  A fuel gas flow path 36 is provided on the surface 18 a of the second separator 18 facing the electrolyte membrane / electrode structure 14. Similar to the oxidant gas flow channel 32, the fuel gas flow channel 36 has a plurality of flow channel grooves extending in the direction of arrow C, and communicates with the fuel gas supply communication hole 22a and the fuel gas discharge communication hole 22b. . A cooling medium flow path 34 communicating with the cooling medium supply communication hole 24a and the cooling medium discharge communication hole 24b is provided on the surface 18b of the second separator 18.

  The first seal member 38 and the second seal member 40 are integrally or individually provided on both surfaces 16a and 16b of the first separator 16 and both surfaces 18a and 18b of the second separator 18. The first seal member 38 and the second seal member 40 are, for example, EPDM, NBR, fluororubber, silicon rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroprene, or acrylic rubber, or a cushioning material. Or use packing material.

  The measuring device 10 is disposed between the fuel cells 12. As shown in FIGS. 1 and 2, the measuring device 10 includes electrode segments 44a and 44b having a substantially identical surface area at a position corresponding to at least a power generation surface region of the electrolyte membrane / electrode structure 14, and a pair of insulating sheets 42a. 42b. Outer peripheral insulating sheets 43a and 43b are provided on the outer periphery of the insulating sheets 42a and 42b.

  The insulating sheet 42a facing the first separator 16 and the insulating sheet 42b facing the second separator 18 divide the power generation surface area of the electrolyte membrane / electrode structure 14 into a plurality of areas and each form a pair of planes. A plurality of rectangular electrode segments 44a and 44b are provided.

  The electrode segments 44a and 44b preferably have a substantially square shape and are provided at the same area and symmetrical positions. The electrode segments 44a and 44b are respectively different poles, and include copper film layers 46a and 46b formed on the insulating sheets 42a and 42b, and gold plating layers 48a and 48b formed on the copper film layers 46a and 46b. Have. An insulating material having the same thickness as that of the electrode segments 44a and 44b is preferably filled between the electrode segments 44a and 44b.

  Between the insulating sheets 42a and 42b, a plurality of thin film resistors 50 are arranged corresponding to the electrode segments 44a and 44b. As the thin film resistor 50, for example, as shown in FIGS. 3 to 6, any one of shunt resistors 50a, 50b, 50c, and 50d is selectively employed.

  As shown in FIG. 3, the shunt resistor 50a has a narrow rectangular shape extending to the opposite side positions of the electrode segments 44a and 44b. The shunt resistor 50a preferably extends to the symmetrical position of the opposite sides of the electrode segments 44a and 44b. As shown in FIG. 4, the shunt resistor 50b has a wide polygonal shape extending to the opposite side positions of the electrode segments 44a and 44b.

  As shown in FIG. 5, the shunt resistor 50c has a meandering shape extending to the diagonal positions of the electrode segments 44a and 44b. As shown in FIG. 6, the shunt resistor 50d has a narrow rectangular shape extending to the diagonal positions of the electrode segments 44a and 44b. The shunt resistors 50a to 50d need only be able to increase the shunt resistance value, and can be set in various shapes.

  One surface of the thin film resistor 50 is provided with a first electrode portion 52a that penetrates one insulating sheet 42a and is connected to one electrode segment 44a. The surface is provided with a second electrode portion 52b that penetrates the other insulating sheet 42b and is connected to the other electrode segment 44b. The 1st electrode part 52a and the 2nd electrode part 52b have plated copper to the hole which penetrates insulating sheets 42a and 42b, and are arranged in the opposite side position or diagonal position of electrode segments 44a and 44b. .

  As shown in FIG. 7, in the measurement apparatus 10, a first wiring pattern 54 a and a second wiring pattern made of a conductive material for voltage acquisition are provided on the thin film resistor 50 provided at the uppermost right end of the front surface. Each end of 56a is connected. The other ends of the first wiring pattern 54a and the second wiring pattern 56a are connected to connectors 58a and 58b, respectively.

  One end of each of the first wiring pattern 54b and the second wiring pattern 56b for voltage acquisition is connected to the second thin film resistor 50 on the left side from the right end of the uppermost front. One end of the first wiring pattern 54c for voltage acquisition and the second wiring pattern 56c is connected to the third thin film resistor 50 on the left side from the right end of the uppermost front. One end of the first wiring pattern 54d and the second wiring pattern 56d for voltage acquisition is connected to the fourth (left end) thin film resistor 50 on the left side from the right end of the top front.

  In each thin film resistor 50, the total length of the first wiring pattern 54a and the second wiring pattern 56a, the total length of the first wiring pattern 54b and the second wiring pattern 56b, the first wiring pattern 54c and the second wiring pattern. The total length of 56c and the total length of the first wiring pattern 54d and the second wiring pattern 56d are set to the same length. The first wiring patterns 54a to 54d and the second wiring patterns 56a to 56d are set to have the same cross-sectional area.

As shown in FIG. 8, a voltmeter 60 is connected to the connectors 58 a and 58 b, and the voltage is detected by each thin film resistor 50. The measuring device 10 detects the current density of the power generation surface area corresponding to each electrode segment 44a, 44b based on the voltage drop detected for each thin film resistor 50. Current density _{i n} of each electrode segment 44a, 44b _is determined from _{i n = V n / (R} n × A n). V _n (V) is a resistance voltage, R _n (Ω) is a resistance value, and _An (cm ² ) is a segment electrode area.

  The operation of the measuring apparatus 10 configured as described above will be described below in relation to the fuel cell 12.

  As shown in FIG. 1, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas supply communication hole 20a, and a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas supply communication hole 22a. Further, a cooling medium such as pure water or ethylene glycol is supplied to the cooling medium supply communication hole 24a.

  The oxidant gas is introduced into the oxidant gas flow path 32 provided in the first separator 16 and moves along the cathode side electrode 28 constituting the electrolyte membrane / electrode structure 14. On the other hand, the fuel gas supplied to the fuel gas supply communication hole 22 a is introduced into the fuel gas flow path 36 of the second separator 18 and moves along the anode side electrode 30 constituting the electrolyte membrane / electrode structure 14.

  Therefore, in each electrolyte membrane / electrode structure 14, the oxidant gas supplied to the cathode side electrode 28 and the fuel gas supplied to the anode side electrode 30 are consumed by an electrochemical reaction in the electrode catalyst layer, Power generation is performed.

  Next, the oxidant gas consumed by being supplied to the cathode side electrode 28 is discharged to the oxidant gas discharge communication hole 20b. Similarly, the fuel gas supplied to and consumed by the anode side electrode 30 is discharged to the fuel gas discharge communication hole 22b.

  The cooling medium supplied to the cooling medium supply communication hole 24 a is introduced into the cooling medium flow path 34 between the first and second separators 16 and 18. The cooling medium cools the electrolyte membrane / electrode structure 14 and then is discharged into the cooling medium discharge communication hole 24b.

  By the way, in the measuring device 10, as shown in FIG. 2, a thin film resistor 50 is provided between the electrode segments 44a and 44b, and when the fuel cell 12 generates electric power, a current flows through the thin film resistor 50. Flows. Therefore, when a voltage drop is measured via the voltmeter 60, a current density distribution for each power generation surface region corresponding to each electrode segment 44a, 44b of the electrolyte membrane / electrode structure 14 is measured from this voltage drop. The

  In this case, in the first embodiment, a plurality of electrode segments 44a and 44b obtained by dividing the power generation surface region of the electrolyte membrane / electrode structure 14 into a plurality of regions are provided, and corresponding to each electrode segment 44a and 44b. A plurality of thin film resistors 50 are provided. Therefore, only by measuring the voltage generated at both ends of the thin film resistor 50, it is possible to measure the current density distribution in each region in the power generation surface.

  Moreover, the first electrode portion 52a and the second electrode portion 52b provided on both surfaces of the thin film resistor 50 are arranged at opposite positions or diagonal positions of the electrode segments 44a and 44b. Specifically, as shown in FIGS. 3 to 6, any of the shunt resistors 50 a, 50 b, 50 c and 50 d can be used for the thin film resistor 50. Thereby, the thin film resistor 50 can increase the resistance length, maximize the resistance value within a limited area, and measure the current density with high accuracy. The advantage that it can be obtained.

  For this reason, for example, it is possible to measure the flooding range and the potential at that time from the measured current density and potential behavior, and based on these information, the deterioration of the electrolyte membrane / electrode structure 14 Can be accurately predicted.

  Further, in each thin film resistor 50, the total length of the first wiring pattern 54a and the second wiring pattern 56a, the total length of the first wiring pattern 54b and the second wiring pattern 56b, the first wiring pattern 54c and the second wiring pattern 56b. The total length of the wiring pattern 56c and the total length of the first wiring pattern 54d and the second wiring pattern 56d are respectively set to the same length.

  Therefore, the resistance of the entire wiring pattern connected to each thin film resistor 50 can be made the same, and there is an effect that the measurement accuracy of the current density distribution in each region is improved.

  The first wiring patterns 54a to 54d and the second wiring patterns 56a to 56d are set to have the same cross-sectional area. Thereby, the measurement accuracy of the current density distribution in each region can be improved.

  FIG. 9 is an explanatory cross-sectional view of a main part of a measuring apparatus 80 according to the second embodiment of the present invention. Note that the same components as those of the measurement apparatus 10 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the measuring device 80, a spacer member 82 having the same thickness as the thin film resistor 50 is interposed between the pair of insulating sheets 42 a and 42 b adjacent to the thin film resistor 50. As shown in FIGS. 10 to 13, in the shunt resistors 50 a, 50 b, 50 c and 50 d employed as the thin film resistor 50, spacers 82 a, 82 b, 82 c and 82 d are employed as the spacer member 82. The spacers 82a, 82b, 82c, and 82d are set to have shapes and numbers corresponding to the shapes of the shunt resistors 50a, 50b, 50c, and 50d, respectively, and are formed in a substantially rectangular shape in the regions of the electrode segments 44a and 44b. Is done.

  In the second embodiment configured as described above, a spacer member 82 having the same thickness as the thin film resistor 50 is interposed between the pair of insulating sheets 42a and 42b. For this reason, the contact state between each electrode segment 44a, 44b can be ensured favorably, and the effect that it becomes possible to reduce the contact resistance with the fuel cell 12 is acquired.

  In the first and second embodiments, the measuring devices 10 and 80 are disposed between the fuel cells 12, but the present invention is not limited to this. For example, as shown in FIG. 14, the measuring devices 10 and 80 can be arranged between the first separator 16 and the second separator 18 instead of the electrolyte membrane / electrode structure 14. Further, the measuring devices 10 and 80 may be arranged at the end of the fuel cell stack in which a plurality of fuel cells 12 are stacked.

DESCRIPTION OF SYMBOLS 10, 80 ... Measuring apparatus 12 ... Fuel cell 14 ... Electrolyte membrane and electrode structure 16, 18 ... Separator 26 ... Solid polymer electrolyte membrane 28 ... Cathode side electrode 30 ... Anode side electrode 32 ... Oxidant gas flow path 34 ... Cooling Medium flow path 36 ... Fuel gas flow paths 42a, 42b ... Insulating sheets 44a, 44b ... Electrode segments 46a, 46b ... Copper film layers 48a, 48b ... Gold plating layers 50 ... Thin film resistors 50a-50d ... Shunt resistances 52a, 52b ... Electrode portions 54a to 54d, 56a to 56d ... Wiring patterns 58a and 58b ... Connector 60 ... Voltmeter 82 ... Spacer member 82a to 82d ... Spacer

Claims (3)

A current density distribution measuring device for a fuel cell in which an electrolyte / electrode structure in which an anode side electrode and a cathode side electrode are provided on both sides of an electrolyte and a separator are laminated,
Dividing a region corresponding to the power generation surface region of the electrolyte / electrode structure into a plurality of regions, and a plurality of planar rectangular electrode segments each forming a pair;
A pair of insulating sheets disposed between the plurality of electrode segments as one pole and the plurality of electrode segments as the other pole;
A plurality of thin film resistors arranged corresponding to each electrode segment between a pair of insulating sheets;
With
On one surface of the thin film resistor, a first electrode portion that penetrates one insulating sheet and is connected to one electrode segment is provided.
The other surface of the thin film resistor is provided with a second electrode portion that penetrates the other insulating sheet and is connected to the other electrode segment,
The first electrode part and the second electrode part are arranged at opposite positions or diagonal positions of the electrode segment ,
Each end of the first wiring pattern and the second wiring pattern for voltage acquisition is connected to the thin film resistor, and each other end of the first wiring pattern and the second wiring pattern is connected to the connector. As
The total length of each thin film resistor connected to said first wiring pattern and the second wiring pattern are respectively set to the same length current density distribution measuring apparatus for a fuel cell characterized by Rukoto.   The current density distribution measuring apparatus according to claim 1, wherein a spacer member having the same thickness as the thin film resistor is interposed between the pair of insulating sheets adjacent to the thin film resistor. A fuel cell current density distribution measuring device. 3. The current density distribution measuring apparatus according to claim 1 or 2 , wherein the first wiring pattern and the second wiring pattern are set to have the same cross-sectional area.

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