JP2008010311A - Method of operating fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of operating a fuel cell by which deterioration of power generation performance can be prevented. <P>SOLUTION: Each membrane-electrode assembly 20 in the fuel cell is constituted by arranging an anode electrode 22 and a cathode electrode 23 on both sides of a solid polymer electrolyte membrane 21; the plurality of membrane-electrode assemblies 20 are stacked via separators 30A and 30B; reaction gas passages (a fuel gas passage 51 and an oxidizer gas passage 52) are formed between a membrane-electrode assembly 20 and a separator 30A, and between a membrane-electrode assembly 20 and a separator 30B; and each cooling medium passage 53 is formed in the space shaped between the separator 30A and the separator 30B. In the operation method of the fuel cell, pressures of the reaction gases supplied to the reaction gas passages 51 and 52 are set higher than that of the cooling medium supplied to the cooling medium passage 53. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for operating a fuel cell.

  In a fuel cell, a membrane electrode structure is formed by sandwiching a solid polymer electrolyte membrane between an anode electrode and a cathode electrode from both sides, and a pair of separators are arranged on both sides of the membrane electrode structure to form a flat unit fuel. A battery (hereinafter referred to as a unit cell) is configured, and a plurality of unit cells are stacked to form a fuel cell stack. In this fuel cell, hydrogen gas is supplied as a fuel gas between the anode electrode and the separator, and air is supplied as an oxidant gas between the cathode electrode and the separator. As a result, hydrogen ions generated by the catalytic reaction at the anode electrode pass through the solid polymer electrolyte membrane and move to the cathode electrode, causing an electrochemical reaction with oxygen in the air at the cathode electrode, thereby generating power. Since power generation involves heat generation, a refrigerant is supplied between adjacent unit cells.

Patent Document 1 describes a technique for balancing the pressure of a cathode gas (oxidant gas) and the pressure of a coolant using a pressure regulator. Specifically, the pressure regulator is divided into two chambers by a deformable bellows, membrane or piston structure inside the pressure regulating container, and one chamber of the pressure regulator is communicated with the oxidant gas passage of the fuel cell. The other room is connected to the circulation passage (refrigerant passage).
JP 2003-3251 A

However, if the pressure of the reaction gas such as oxidant gas is equal to the pressure of the refrigerant, the refrigerant flows into the reaction gas passage between the separator and the electrode, and the membrane electrode structure is damaged, generating power. Performance may be reduced.
Accordingly, an object of the present invention is to provide a method of operating a fuel cell that can prevent a decrease in power generation performance.

  In order to solve the above-mentioned problems, the invention according to claim 1 is characterized in that an anode electrode (for example, the anode electrode 22 in the embodiment) is provided on both sides of a solid polymer electrolyte membrane (for example, the solid polymer electrolyte film 21 in the embodiment). A cathode electrode (for example, the cathode electrode 23 in the embodiment) is provided to form a membrane electrode structure (for example, the membrane electrode structure 20 in the embodiment), and a plurality of the membrane electrode structures are separated from the separator (for example, in the embodiment). And a reaction gas passage (for example, the fuel gas passage 51 and the oxidant gas passage 52 in the embodiment) is provided between the membrane electrode structure and the separator. In addition, a fuel provided with a refrigerant passage (for example, the refrigerant passage 53 in the embodiment) inside the separator. Cell (e.g., a fuel cell 1 in the embodiment) A method of operating, the pressure of the reaction gas supplied to the reaction gas passage, and setting higher than the pressure of the refrigerant supplied to the refrigerant passage.

  The invention according to claim 2 is characterized in that a difference between the pressure of the reaction gas and the pressure of the refrigerant is 10 kPa or more and 30 kPa or less.

  According to a third aspect of the present invention, a fuel gas passage (for example, the fuel gas passage 51 in the embodiment) is provided as the reaction gas passage between the anode electrode and the separator, and between the cathode electrode and the separator. An oxidant gas passage (for example, the oxidant gas passage 52 in the embodiment) is provided between them, and the pressure of the fuel gas supplied to the fuel gas passage is set higher than the pressure of the oxidant gas supplied to the oxidant gas passage. It is characterized by doing.

  According to the first aspect of the invention, it is possible to prevent the refrigerant from flowing into the reaction gas passage from the refrigerant passage. Therefore, it can prevent that a membrane electrode structure receives a damage with a refrigerant | coolant, and power generation performance falls.

  According to the invention of claim 2, since the differential pressure between the reaction gas and the refrigerant is 10 kPa or more, it is possible to reliably prevent the membrane electrode structure from being damaged by the refrigerant and reducing the power generation performance. . In addition, since the differential pressure between the reaction gas and the refrigerant is 30 kPa or less, it is possible to ensure the contact surface pressure between the separator and the membrane electrode structure, and to suppress the increase in contact resistance and improve the power generation performance. Can do.

  According to the third aspect of the present invention, it becomes possible to accurately detect the concentration of the fuel gas that has permeated through the membrane electrode structure in the oxidant gas after use, and to restrict the discharge of the fuel gas. it can.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Fuel cell stack)
FIG. 1 is a schematic perspective view of the fuel cell stack 1. The fuel cell stack 1 is formed by stacking a number of unit fuel cells 10 (hereinafter referred to as unit cells) 10 that are elongated in the vertical direction and electrically connecting them in series. End plates 90A and 90B are disposed on both sides of the unit fuel cells. It is configured by fastening. A fuel cell stack (hereinafter simply referred to as “fuel cell”) 1 of this embodiment is arranged in a vehicle or the like with the vertical direction directed to the vertical direction. Hereinafter, the arrows X and Y in the figure indicate the horizontal direction, and the arrow Z indicates the vertical direction.

  As shown in FIG. 2, the unit cell 10 has a sandwich structure in which separators 30 </ b> A and 30 </ b> B are disposed on both sides of the membrane electrode structure 20. Specifically, as shown in FIG. 3, the membrane electrode structure 20 is configured by providing an anode electrode 22 and a cathode electrode 23 on both sides of a solid polymer electrolyte membrane (electrolyte membrane) 21 made of, for example, a fluorine-based electrolyte material. Has been. It is desirable to provide a reactive gas diffusion layer outside each electrode. The anode electrode separator 30 </ b> A faces the anode electrode 22 of the membrane electrode structure 20, and the cathode separator 30 </ b> B faces the cathode electrode 23. Both separators 30A and 30B are formed by press-molding a metal plate in a predetermined manner. In a fuel cell formed by stacking unit cells, in two adjacent unit cells, the anode side separator 30A of one unit cell and the cathode side separator 30B of the other unit cell are in close contact. In addition, the coating for reducing contact resistance is given to the surface of separator 30A, 30B.

  In FIG. 2, the upper left corner of the membrane electrode structure 20 and both separators 30A, 30B is provided with a fuel gas supply port 11 through which fuel gas before use (for example, hydrogen gas) circulates. In a lower right corner, an anode off-gas discharge port 12 through which used fuel gas (hereinafter referred to as anode off-gas) flows is provided. Similarly, in the upper right corner of the membrane electrode structure 20 and both separators 30A and 30B, an oxidant gas supply port 13 through which the oxidant gas before use is circulated is provided. Is provided with a cathode offgas discharge port 14 through which the oxidant gas after use (hereinafter referred to as cathode offgas) flows. Further, at the left end of the membrane electrode structure 20 and both separators 30A, 30B, four refrigerant supply ports 15, 15,. In the section, four refrigerant outlets 16, 16,... Through which the used refrigerant flows are arranged in a column. These fuel gas supply port 11, anode offgas discharge port 12, oxidant gas supply port 13, cathode offgas discharge port 14, refrigerant supply ports 15, 15..., Refrigerant discharge ports 16, 16. Are provided penetrating in the stacking direction.

  30 A of anode side separators are provided with the flat part 36 which surface-contacts to the membrane electrode structure 20, and are in the rectangular area | region pinched | interposed between the refrigerant | coolant supply port 15,15 ... and the refrigerant | coolant discharge port 16,16 .... A protrusion 31A protruding in a direction away from the membrane electrode structure 20 is formed. A large number of the protrusions 31A are formed with the longitudinal direction thereof oriented in the vertical direction, and are arranged in parallel at equal intervals in the horizontal direction (X direction). Each ridge 31A extends in the vertical direction while meandering in a substantially trapezoidal wave pattern. As shown in FIG. 3, the cross-sectional shape of the ridge 31 </ b> A has a trapezoidal shape having a flat top portion 35, and the ends of the adjacent ridges 31 </ b> A and 31 </ b> A are connected by a flat portion 36.

  Returning to FIG. 2, a seal portion 43 made of an insulating resin (for example, silicon resin) is provided on the surface of the anode separator 30 </ b> A that is in close contact with the membrane electrode structure 20. The seal portion 43 surrounds and surrounds the outer side of the protrusion 31A from the fuel gas supply port 11 to the anode offgas discharge port 12, and the oxidant gas supply port 13, the cathode offgas discharge port 14, and the refrigerant supply ports 15 and 15 respectively. ... each refrigerant | coolant discharge port 16,16 ... is enclosed individually, respectively.

  The anode-side separator 30 </ b> A is attached with the flat portion 36 and the seal portion 43 in close contact with the anode electrode of the membrane electrode structure 20. The space formed between the protrusion 31A of the anode separator 30A and the membrane electrode structure 20 becomes the fuel gas passage 51 through which the fuel gas flows. As a result, the fuel gas introduced into the fuel gas passage 51 via the fuel gas supply port 11 flows through the upper buffer portion 37, the protrusion 31A, and the lower buffer portion 40 in this order, and is discharged to the anode off-gas discharge port 12. The

  The cathode side separator 30B has substantially the same configuration as the anode side separator 30A, and the space formed between the protrusion 31B of the cathode side separator 30B and the membrane electrode structure 20 is an oxidant gas in which the oxidant gas flows. A passage 52 is formed. As a result, the oxidant gas introduced into the oxidant gas passage via the oxidant gas supply port 13 circulates in order through the upper buffer part 37, the protrusion 31B, and the lower buffer part 40, and enters the cathode offgas discharge port 14. Discharged.

  Further, as shown in FIG. 2, a seal portion 44 made of an insulating resin (for example, silicon resin) is also provided on the back surface of the cathode separator 30B that is in close contact with the membrane electrode structure 20. The seal portion 44 surrounds and surrounds the outside of the ridge 31B from the refrigerant supply ports 15, 15... To the refrigerant discharge ports 16, 16,..., As well as the fuel gas supply port 11 and the anode offgas discharge port 12. The oxidant gas supply port 13 and the cathode offgas discharge port 14 are individually enclosed. Similar to the cathode-side separator 30B, a similar seal portion 44 is provided on the back surface of the anode-side separator 30A that is in close contact with the membrane electrode structure 20.

  In a fuel cell in which unit cells 10 are stacked, in two adjacent unit cells 10, 10, the seal portion 44 of the anode side separator 30 </ b> A of one unit cell 10 and the cathode side separator 30 </ b> B of the other unit cell 10. The seal portion 44 is brought into close contact. Thereby, the refrigerant path 53 is formed in the space between both separators 30A and 30B.

The refrigerant passage 53 will be described in detail with reference to FIGS. FIG. 4 representatively shows one protrusion 31A of the anode separator 30A and one protrusion 31B of the cathode separator 30B.
As described above, since the protrusion 31A of the anode-side separator 30A and the protrusion 31B of the cathode-side separator 30B are out of phase with each other, the top 35 of the first straight portion 32 and the protrusion 31B in the protrusion 31A. When the top portion 35 of the first straight portion 32 is overlapped closely, the top portion 35 of the second straight portion 33 in the protrusion 31A and the top portion 35 of the second straight portion 33 in the protrusion 31B do not overlap. , Are spaced apart from each other in the horizontal direction, and an opening 60 is formed therebetween.

  Further, the top portion 35 of the second straight portion 33 in the protrusion 31A of the anode separator 30A is disposed away from the flat portion 36 of the cathode separator 30B, and similarly, the protrusion 31B of the cathode separator 30B. The top portion 35 of the second straight portion 33 is spaced from the flat portion 36 of the anode separator 30A. As a result, the refrigerant passage 53 formed between the anode-side separator 30A and the cathode-side separator 30B is blocked in the horizontal direction at the portion where the first straight portions 32, 32 of the ridges 31A, 31B are abutted. However, it communicates in the horizontal direction at the portion where the second straight portions 33, 33 of the ridges 31A, 31B are present.

  As a result, the refrigerant introduced into the refrigerant passage 53 from the refrigerant supply port flows in the horizontal direction so as to sew between the second straight portion 33 of the protrusion 31A and the second straight portion 33 of the protrusion 31B. Flow to the corresponding refrigerant outlet. That is, while the fuel gas and the oxidant gas flow in the vertical direction, the refrigerant flows in a horizontal direction orthogonal to the flow direction of these reaction gases.

  In the fuel cell and unit cell configured as described above, the hydrogen ions generated by the catalytic reaction at the anode electrode 22 shown in FIG. 3 pass through the solid polymer electrolyte membrane 21 and move to the cathode electrode 23, and the cathode electrode. At 23, an electrochemical reaction with oxygen occurs to generate electricity. In order to prevent the unit cell from exceeding a predetermined operating temperature due to the heat generated by this power generation, the refrigerant flowing through the refrigerant passage 53 is deprived of heat and cooled.

(Fuel cell operation method)
FIG. 5 is a block diagram showing the configuration of the fuel cell operation system. The fuel cell 1 generates power by supplying hydrogen gas as a fuel gas to the fuel gas passage 51 and supplying air as an oxidant gas to the oxidant gas passage 52. In addition, a refrigerant such as an ethylene glycol aqueous solution is supplied to the refrigerant passage 53 to cool the fuel cell 1.

The air is pressurized by the air compressor 102, humidified by the cathode humidifier 103, and supplied to the oxidant gas passage 52 of the fuel cell 1. After this oxygen in the air is provided as an oxidant, it is discharged from the fuel cell 1 as a cathode off gas and released to the atmosphere via the pressure control valve 104. The ECU 110 drives the air compressor 102 to supply a predetermined amount of air to the fuel cell 1 and controls the pressure control valve 104 in accordance with the output required for the fuel cell 1 (hereinafter, required output). the supply pressure P _a of air to the oxidant gas passage 52 is adjusted to a pressure corresponding to the required output of the fuel cell 1.

  On the other hand, the hydrogen gas released from the high-pressure hydrogen tank 130 is decompressed by the regulator 105, passes through the ejector 106, is humidified by the anode humidifier 107, and is supplied to the fuel gas passage 51 of the fuel cell 1. After this hydrogen gas is used for power generation, it is discharged from the fuel cell 1 as an anode off-gas, drawn into the ejector 106 through the anode off-gas recovery path 111, and merged with the hydrogen gas supplied from the high-pressure hydrogen tank 130. The fuel cell 1 is supplied again and circulated. The anode off gas recovery path 111 is connected to an anode off gas discharge path 112 via an electromagnetically driven purge valve 108.

  The refrigerant stored in the refrigerant tank 150 is pressurized by the pump 152 and supplied to the refrigerant passage 53 of the fuel cell 1. The refrigerant used for cooling the fuel cell 1 is sent to the heat exchanger 158 via the pressure control valve 156. The refrigerant cooled in the heat exchanger 158 is returned to the refrigerant tank 150. The ECU 110 drives the pump 152 according to the operating state of the fuel cell 1 to supply a predetermined amount of refrigerant to the fuel cell 1 and controls the pressure control valve 156 to adjust the supply pressure of the refrigerant to the refrigerant passage 53. .

In the present embodiment, the pressure P _R (P _H and P _A ) of the reaction gas (hydrogen gas and air) supplied to the reaction gas passage (the fuel gas passage 51 and the oxidant gas passage 52) of the fuel cell 1 is used as the refrigerant passage. It is set higher than the pressure _{P M} of the refrigerant supplied to 53. If the reaction gas pressure P _R is less than the refrigerant pressure P _M, the refrigerant flows into the reaction gas passages 51 and 52 from the refrigerant passage 53 in FIG. 3, the membrane electrode assembly (especially reactive gas diffusion layer) 20 is damaged This is because the power generation performance may be reduced. Incidentally separator 30A partitioning the reaction gas passages 51 and 52 and the refrigerant passage 53, 30B, the difference between which is configured by the dense material of the metal plate or the like, a reactive gas pressure P _R and the refrigerant pressure P _M It is possible to set the pressure.

Specifically, the differential pressure _P R -P _M with a reactive gas pressure _{P R} and the refrigerant pressure _{P M} is set to be 10kPa or 30kPa or less. This is because when the differential pressure is less than 10 kPa, the refrigerant easily flows from the refrigerant passage 53 into the reaction gas passages 51 and 52 as described above.

On the other hand, when the differential pressure P _R -P _M exceeds 30 kPa, the pressure of the reaction gas passages 51 and 52 in FIG. Along with this, the contact surface pressure between the flat portions 36 of the separators 30A and 30B and the membrane electrode structure 20 decreases. In addition, since separator 30A, 30B of this embodiment is comprised, for example with the metal plate of thickness 1mm or less, it is easy to bend | bend by the pressure difference of front and back, and the fall of a contact surface pressure appears notably. Therefore, the electrical resistance (contact resistance) at the contact portion between the separators 30A and 30B and the membrane electrode structure 20 increases, and the resistance overvoltage increases. Thereby, the extraction efficiency of the electric power generated in the unit cell is lowered, and consequently the power generation performance is lowered. On the other hand, if the differential pressure is set to 30 kPa or less, it becomes possible to ensure the contact surface pressure between the separators 30A and 30B and the membrane electrode structure 20, and suppress the increase in contact resistance to improve the power generation performance. Can be improved.

FIG. 7 is a graph showing the relationship between the current taken out from the fuel cell and the resistance overvoltage. In FIG. 7, the case where the differential pressure ΔP (P _R −P _M ) is 10 kPa or more and 30 kPa or less is indicated by a solid line, and the case where the differential pressure ΔP exceeds 30 kPa is indicated by a broken line. According to FIG. 7, when the same current is obtained, the resistance overvoltage of the solid line is lower than the resistance overvoltage of the broken line. That is, by setting the differential pressure to 10 kPa or more and 30 kPa or less, it is possible to improve the power extraction efficiency and thus improve the power generation performance.

  In the present embodiment, the pressure of hydrogen gas supplied to the fuel gas passage 51 of the fuel cell 1 is set higher than the pressure of air supplied to the oxidant gas passage 52 by the regulator 105 shown in FIG. The regulator 105 is composed of, for example, a pneumatic proportional pressure control valve, introduces the air pressure at the outlet of the air compressor 102 as a signal pressure, and the hydrogen gas pressure at the outlet of the regulator 105 has a predetermined pressure range corresponding to the signal pressure. The pressure reduction is controlled so that

The structure of the regulator 105 will be described with reference to the schematic sectional view of FIG.
The internal space of the body 121 of the regulator 105 is partitioned up and down by pressure regulating diaphragms 122a and 122b (122). A space above the diaphragm 122 a is a signal pressure chamber 123. The signal pressure chamber 123 is a sealed space, and air pressurized by the compressor is introduced into the signal pressure chamber 123 from the air introduction hole 125 through the air signal introduction path 115. The signal pressure chamber 123 is provided with a bias setting spring (elastic body) 129 for biasing the diaphragm 122a downward.

  On the other hand, a space below the diaphragm 122b is a hydrogen gas passage 124. The hydrogen gas passage 124 is partitioned by a horizontally arranged valve seat portion 128, the lower side being a first hydrogen gas passage 124 a and the upper side being a second hydrogen gas passage 124 b. The hydrogen gas flows from the hydrogen supply pipe 113 through the hydrogen gas inlet 131 into the first hydrogen gas passage 124a, passes through the flow hole 133 formed in the valve seat portion 128, and then passes through the second hydrogen gas passage 124b. It flows out to the hydrogen supply pipe 113 through the hydrogen gas outlet 132. A stem 126 is attached to the lower surface of the diaphragm 122b. The stem 126 is provided with a valve element 127 that can be seated and separated from the flow hole 133 of the valve seat portion 128 from below.

  In the regulator 105 configured as described above, when the first thrust acting downward on the diaphragm 122 is larger than the second thrust acting upward, a downward force acts on the diaphragm 122, and the valve body 127. Is pushed away from the valve seat portion 128 (ie, in the valve opening direction). Thereby, since the flow hole 133 formed in the valve seat part 128 is opened from the valve body 127, hydrogen gas flows from the first hydrogen gas passage 124a through the flow hole 133 into the second hydrogen gas passage 124b.

  Thereafter, when the pressure of the second hydrogen gas passage 124b increases, the second thrust becomes larger than the first thrust, and an upward force acts on the diaphragm 122, so that the valve element 127 approaches the valve seat portion 128 ( That is, it pushes in the valve closing direction). As a result, the flow hole 133 formed in the valve seat portion 128 is closed by the valve body 127. By repeating the above operation, the first thrust and the second thrust are balanced.

First thrust acting downwards relative to the diaphragm 122, the pressure P ₁ of the air pressurized by the compressor, which is the sum of the pressing force P _C by the bias setting spring 129. The second thrust acting upward is the hydrogen gas pressure P ₂ at the outlet of the regulator 105. By the first thrust and a second thrust is balanced, it is possible to set the hydrogen gas pressure P ₂ higher than the air pressure P _1. The pressing force P _C by the bias setting spring 129 is constant, it is possible to hold the difference between the hydrogen gas pressure P ₂ and the air pressure P ₁ by the regulator 105 to a constant.

Incidentally, the pressure P ₁ of the air at the outlet of the compressor 102 shown in FIG. 5, are different from each other and supply pressure P _A of air to the oxidant gas channel 52. The pressure P ₂ of the hydrogen gas at the outlet of the regulator 105, are different from each other and supply pressure P _H of the air to the fuel gas passage 51. However, ECU 110 described above, by controlling the pressure control valve 104, to set the supply pressure _{P A} of air to the oxidant gas passage 52 to a predetermined value. Moreover, if properly setting the pressure difference between the air pressure P ₁ and the hydrogen gas pressure P ₂ in this case by a bias setting spring of the regulator 105, the supply of the supply pressure P _H and the air of the hydrogen gas to the fuel cell 1 it is possible to set a differential pressure between the pressure P _a to a predetermined value.

In the present embodiment, the pressure P _H of the hydrogen gas supplied to the fuel gas passage 51 of the fuel cell 1, is set to be higher than the pressure P _A of the air supplied to the oxidant gas channel 52.
Since hydrogen gas has a small molecular weight, a part of the hydrogen gas supplied to the fuel gas passage 51 inevitably permeates the membrane electrode structure. In order to monitor the permeation of the hydrogen gas, the concentration of the hydrogen gas is detected at the outlet of the oxidant gas passage 52. Here, the supply pressure P _H of the hydrogen gas by increasing the feed pressure P _A of the air, it is possible to accurately detect the concentration of hydrogen gas. Thereby, discharge of hydrogen gas can be regulated.

Further in this embodiment, the differential pressure _P H -P _A of hydrogen gas pressure _{P H} and the air pressure _{P A} is set to be 10kPa or 30kPa or less. This is because when the differential pressure is less than 10 kPa, the concentration of hydrogen gas that has passed through the membrane electrode structure 20 shown in FIG. 2 cannot be detected accurately.
On the other hand, when the differential pressure exceeds 30 kPa, excessive stress acts on the membrane electrode structure 20 sandwiched between the anode-side separator 30A and the cathode-side separator 30B, thereby reducing the power generation capacity.

The present invention is not limited to the embodiment described above.
For example, in the above-described embodiment, all the refrigerant passages are provided between two adjacent unit cells. However, the refrigerant passages may be provided by being thinned out without being provided between all the unit cells. In this case, at the portion where the refrigerant passage is thinned out, two adjacent unit cells share one separator, and the separator functions as an anode separator in one unit cell, and serves as a cathode separator in the other unit cell. Function.
In the embodiment, a structure in which separators having corrugated ridges in which the flow direction of the reaction gas and the flow direction of the refrigerant intersect is employed, but the structure is not limited to this structure, and the flow of the reaction gas The direction and the flow direction of the refrigerant may be any.

It is a schematic perspective view of a fuel cell stack. FIG. 3 is an exploded view of a unit fuel cell constituting the fuel cell stack. It is a fragmentary sectional view of a fuel cell stack. It is a perspective view which shows the separator lamination state in the said fuel cell stack. It is a block diagram of a fuel cell. It is sectional drawing of a regulator. It is a graph which shows the relationship between an electric current and resistance overvoltage.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Fuel cell 20 ... Membrane electrode structure 21 ... Solid polymer electrolyte membrane 22 ... Anode electrode 23 ... Cathode electrode 30A ... Anode side separator 30B ... Cathode side separator 51 ... Fuel gas passage 52 ... Oxidant gas passage 53 ... Refrigerant passage

Claims (3)

An anode electrode and a cathode electrode are provided on both sides of the solid polymer electrolyte membrane to form a membrane electrode structure, and a plurality of the membrane electrode structures are stacked with a separator interposed between the membrane electrode structure and the separator. A method of operating a fuel cell in which a reaction gas passage is provided in the separator and a refrigerant passage is provided in the separator,
A method of operating a fuel cell, characterized in that a pressure of a reaction gas supplied to the reaction gas passage is set higher than a pressure of a refrigerant supplied to the refrigerant passage.   The method of operating a fuel cell according to claim 1, wherein the difference between the pressure of the reaction gas and the pressure of the refrigerant is 10 kPa or more and 30 kPa or less. As the reaction gas passage, a fuel gas passage is provided between the anode electrode and the separator, and an oxidant gas passage is provided between the cathode electrode and the separator.
3. The method of operating a fuel cell according to claim 1, wherein the pressure of the fuel gas supplied to the fuel gas passage is set higher than the pressure of the oxidant gas supplied to the oxidant gas passage. .

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