JP2014037620A - Device for reducing oxygen, chamber for reducing oxygen and refrigerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for reducing oxygen which can prevent the occurrence of a flooding phenomenon, and perform CA storage in stable performance.SOLUTION: A device for reducing oxygen 102 using a polymer electrolyte 116 includes an anodic water control part 126 between an anode 118 and a water supply body 128.

Description

  Embodiments of the present invention relate to an oxygen reduction device, an oxygen reduction chamber using the oxygen reduction device, and a refrigerator having these.

  Conventionally, the CA (Controlled Atmosphere) storage method includes a gas replacement method that is widely used in the food industry, a vacuum method that reduces oxygen by reducing the pressure, and a polymer electrolyte membrane that reduces oxygen in the CA storage room. For example, a polymer electrolyte method, an adsorption method using an oxygen adsorbent, and the like.

  The gas replacement method is a method in which a gas typified by nitrogen or carbon dioxide gas is stored by being replaced with air, and is widely used for maintaining freshness in the distribution process of food and vegetables.

  The vacuum method is a method of depressurizing as a method of reducing oxygen in order to prevent oxidation of food. Since the performance correlates with the degree of vacuum, the strength of the storage container and the capacity of the vacuum pump are required, which makes the apparatus relatively large.

  The method using an oxygen adsorbent is also widely used in the distribution process of confectionery and the like as in the gas replacement method.

  In the polymer electrolyte membrane method, hydrogen is electrolyzed at the anode to form hydrogen ions, and the hydrogen ions move through the polymer electrolyte membrane to reach the cathode and react with oxygen in the storage container to produce water. By consuming oxygen. Therefore, there is a merit that the pressure change is small and the strength of the storage container is not necessary.

JP 2004-218924 A Japanese Patent Laid-Open No. 9-287869 JP-A-6-184237

  However, in the polymer electrolyte membrane method, when the anode water supply is supplied as liquid water, the water moves through the polymer electrolyte membrane and reaches the cathode, and the reaction between hydrogen ions and oxygen at the cathode. This causes a so-called “flooding phenomenon” that hinders the performance of the oxygen reduction reaction.

  Therefore, an object of the embodiment of the present invention is to provide an oxygen reduction device, an oxygen reduction chamber, and a refrigerator that can prevent the occurrence of a flooding phenomenon and perform CA storage with stable performance.

  The present embodiment includes a polymer electrolyte membrane, an anode provided on one side of the polymer electrolyte membrane, a cathode provided on the other side of the polymer electrolyte membrane and leading to a reduced oxygen space, and the anode An anode current collector for energizing the cathode, a cathode current collector for energizing the cathode, a water supply body provided on the anode side, provided between the anode and the water supply body, from the water supply body And an anode water adjusting unit that suppresses the amount of water that moves to the anode.

It is a longitudinal cross-sectional view from the side of the refrigerator of Embodiment 1. It is the longitudinal cross-sectional view from the front of a refrigerator similarly. 1 is an enlarged longitudinal sectional view of an oxygen reduction device according to Embodiment 1. FIG. It is a disassembled perspective view of an oxygen reduction unit. It is a front view of an oxygen reducing device. It is a rear view of an oxygen reducing device. It is a longitudinal cross-sectional view of an oxygen reducing device. It is a longitudinal cross-sectional view of a refrigerator compartment lower part and a vegetable compartment, Comprising: It is the state which closed the door of the vegetable compartment. Similarly, the vegetable room door is pulled out. Similarly, the vegetable room door and the oxygen-reducing container are pulled out. It is a refrigeration cycle of a refrigerator. It is a block diagram of a refrigerator. It is an expansion longitudinal cross-sectional view of the oxygen reduction apparatus of the modification 1 of Embodiment 1. FIG. It is an expanded longitudinal cross-sectional view of the oxygen reduction apparatus of the modification 2 of Embodiment 1. FIG. It is a longitudinal cross-sectional view of the oxygen reduction apparatus of Embodiment 2. It is a disassembled perspective view of an oxygen reduction unit. It is a disassembled perspective view of an oxygen reducing device. It is a perspective view of a front case. It is a semi-vertical cross-sectional perspective view of a rear case. It is a longitudinal cross-sectional view of a water supply apparatus. It is a figure of the table showing a test result. It is a perspective view of the front case of the modification 1 of Embodiment 2. FIG. It is a perspective view of the front case of the modification 2 of Embodiment 2. FIG. It is a perspective view of the front case of the modification 3 of Embodiment 2. FIG. It is a perspective view of the front case of the modification 4 of Embodiment 2. FIG. It is a schematic sectional drawing which shows a part of refrigerator of Embodiment 3. It is sectional drawing which shows schematically the structure of the oxygen reduction apparatus used for the refrigerator of Embodiment 3. It is a 1st table | surface of the measurement result in the refrigerator of Embodiment 3. It is a 2nd table | surface of the measurement result in the refrigerator of Embodiment 3. It is a 3rd table | surface of the measurement result in the refrigerator of Embodiment 3. It is a 4th table | surface of the measurement result in the refrigerator of Embodiment 3. It is a 5th table | surface of the measurement result in the refrigerator of Embodiment 3. It is a 6th table | surface of the measurement result in the refrigerator of Embodiment 3. It is a 7th table | surface of the measurement result in the refrigerator of Embodiment 3. FIG. It is an 8th table | surface of the measurement result in the refrigerator of Embodiment 3. It is explanatory drawing of the effect of embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION

  Hereinafter, an oxygen reduction device for a refrigerator according to an embodiment will be described with reference to the drawings.

Embodiment 1

  The oxygen reduction apparatus 102 of the refrigerator 10 of Embodiment 1 is demonstrated based on FIGS. The refrigerator 10 of this embodiment has an oxygen reduction chamber 100, and the oxygen reduction chamber 100 has an oxygen reduction device 102.

(1) Structure of refrigerator 10 The structure of the refrigerator 10 is demonstrated based on FIG. 1 and FIG. FIG. 1 is a longitudinal sectional view as seen from the side of the entire refrigerator 10, and FIG. 2 is a longitudinal sectional view as seen from the front.

  The cabinet 12 of the refrigerator 10 is a heat insulation box, and is formed of an inner box and an outer box, and a heat insulating material is filled between the inner box and the outer box. The inside of the cabinet 12 has a refrigerator compartment 14, a vegetable compartment 16, a small freezer compartment 18 and a freezer compartment 20 in order from the top, and an ice making room 19 is provided beside the small freezer compartment 18. A heat insulating partition 36 is provided between the vegetable compartment 16, the small freezer compartment 18 and the ice making compartment 19. The refrigerator compartment 14 and the vegetable compartment 16 are partitioned by a horizontal partition 38. A front door 14a is provided on the front of the refrigerator compartment 14, and drawer doors 16a, 18a, 20a are provided in the vegetable compartment 16, the small freezer compartment 18, the freezer compartment 20, and the ice making compartment 19, respectively. Yes.

  A machine room 22 is provided at the bottom of the back surface of the cabinet 12, and a compressor 24 and the like constituting the refrigeration cycle are placed thereon. A control plate 26 is provided on the upper back of the machine room 22.

  A refrigeration evaporator (hereinafter referred to as “R EVA”) 28 is provided from the lower back of the refrigerator compartment 14 to the back of the vegetable compartment 16, and a refrigeration blower (hereinafter referred to as “R fan”) 30 is provided below the evaporator. Is provided. The R EVA 28 and the R fan 30 are disposed in an R EVA chamber 17 formed by the EVA cover 15. A freezing evaporator (hereinafter referred to as “F EVA”) 32 is provided from the back of the small freezer 18 to the back of the freezer 20, and a freezing fan (hereinafter referred to as “F fan”) 34 is provided above the evaporator. It has been. The cold air cooled by the R evaporator 28 is sent to the refrigerator compartment 14 and the vegetable compartment 16 by the R fan 30. The cold air cooled by the F evaporator 32 is blown by the F fan 34 to the small freezer compartment 18, the ice making chamber 19, and the freezer compartment 20.

  A refrigeration room sensor (hereinafter referred to as “R sensor”) for detecting the internal temperature of the refrigeration room 14 is provided on the back surface of the refrigeration room 14, and the internal temperature of the freezer room 20 is provided on the back surface of the freezer room 20. A refrigerating sensor (hereinafter referred to as “F sensor”) 35 is provided.

(2) Cold room 14 and vegetable room 16
Next, the structure of the refrigerator compartment 14 and the vegetable compartment 16 is demonstrated.

  As shown in FIG. 1, the refrigerator compartment 14 is provided with a plurality of shelves 40, and a chilled chamber 44 having a drawer-type chilled container 42 is provided at the lower part. The chilled chamber 44 is a low temperature chamber and stores meat and fish. A plurality of door pockets 46 are provided on the back surface of the door 14 a of the refrigerator compartment 14.

  As shown in FIGS. 8 to 10, the vegetable compartment 16 is provided with a drawer-type vegetable container 48 and is supported by a pair of left and right moving rails 50, 50 protruding rearward from the back surface of the door 16 a of the vegetable compartment 16. The pair of left and right moving rails 50, 50 move in the horizontal direction on fixed rails 52, 52 provided on the right inner wall and the left inner wall of the vegetable compartment 16, respectively.

  A hypoxic chamber 100 is provided at the rear of the partition 38 that hits the ceiling of the vegetable compartment 16. An oxygen reduction device 102 is provided at the rear of the oxygen reduction chamber 100. The oxygen reduction chamber 100 and the oxygen reduction device 102 will be described in detail later.

  Note that the oxygen reduction chamber 100 may be provided in the chilled chamber 44. This is because the fats and oils contained in the meat stored in the chilled chamber 44 are prevented from being oxidized and are suitable for storing meat and the like.

(3) Hypoxic chamber 100
Next, the structure of the oxygen reduction chamber 100 will be described with reference to FIGS. 1 and 8 to 10.

  As shown in FIG. 1, the oxygen reduction chamber 100 includes a container storage unit 104 that is suspended from a partition 38, an oxygen reduction container 106 that can be drawn forward from the container storage unit 104, and the oxygen reduction device 100. .

  As shown in FIGS. 8 to 10, the container storage portion 104 is suspended from the partition body 36, the ceiling surface of the container storage portion 104 is configured by the partition body 36, the front surface is open, and the back surface, both side surfaces, and the bottom surface are covered. I have it.

  As shown in FIGS. 8 to 10, the oxygen reduction container 106 can be pulled out from the front surface of the opened container housing portion 104, and the front surface of the oxygen reduction container 106 also serves as the door 108. A frame-like gasket 110 is provided on the four circumferences of the back surface of the door 108, and the oxygen reduction chamber 100 is hermetically sealed when the oxygen reduction container 106 is stored in the container storage portion 104.

As shown in FIGS. 8 to 10, a CO ₂ sensor 72 as food storage detection means is provided on the front side of the back surface of the container storage unit 104. When the food 58 such as vegetables is stored in the oxygen reduction chamber 100 and the vegetables breathe and discharge CO ₂ , the CO ₂ sensor 72 detects the discharged CO ₂ and outputs a signal. Thereby, it can be detected that the food 58 is stored in the oxygen reduction chamber 100. Note that a weight sensor, an infrared sensor, or the like may be used as the food storage detection means.

  As shown in FIGS. 8 to 10, a vent hole 112 is opened on the rear rear side of the container housing portion 104, and the oxygen reduction device 102 is attached to the position of the vent hole 112.

(4) Oxygen reduction device 102
Next, the structure of the oxygen reduction device 102 will be described with reference to FIGS.

  In the oxygen reduction device 102 using the polymer electrolyte membrane method, an oxygen reduction unit 115 is provided inside a box-shaped case 114 having heat insulation properties.

(4-1) Oxygen reduction unit 115
First, the oxygen reduction unit 115 is demonstrated based on FIG.3 and FIG.4. FIG. 3 is a longitudinal sectional view of the oxygen reduction device 102, and FIG. 4 is an exploded perspective view of the oxygen reduction unit 115. In FIGS. 3 and 4, the thickness of each member is thin, but the thickness is enlarged and described for easy understanding.

  A polymer electrolyte membrane (hereinafter simply referred to as “electrolyte membrane”) 116 is provided in the vertical direction, an anode 118 is provided at the rear of the electrolyte membrane 116, and a cathode 120 is provided at the front of the electrolyte membrane 116. . The cathode 120 is a laminate of a carbon catalyst and carbon paper. Further, platinum catalyst is supported on the anode 118 and the cathode 120, respectively. The electrolyte membrane 116, the anode 118, and the cathode 120 are integrally joined using a hot press or the like. A positive anode current collector 122 is provided behind the anode 118, and a negative cathode current collector 124 is provided in front of the cathode 120. Both current collectors 122 and 124 are mesh-like titanium films whose surfaces are plated with platinum. The anode current collector 122 performs positive energization on the anode 118, and the cathode current collector 124 provides negative energization on the cathode 120. Do. Both current collectors 122 and 124 are energized from electric wires 158 and 160. Further, an insulator 125 is provided between the current collectors 122 and 124 so that the current collectors 122 and 124 do not contact each other. The insulator 125 has a frame shape, and the electrolyte membrane 116, the anode 118, and the cathode 120 are accommodated therein.

  A water repellent layer 126 is provided behind the anode current collector 122. The water repellent layer 126 is provided inside the frame-shaped gasket 126. A water repellent layer 130 is also provided in front of the cathode current collector 124, and the water repellent layer 130 is also provided inside the frame-shaped gasket 131. As the water repellent layers 126 and 130, polymer films are used. Although many polymer films are water-repellent, it is necessary to permeate water vapor. Therefore, depending on the material, it is necessary to adjust the thickness, and water vapor, which is gaseous water, does not permeate liquid water. As the property of permeation, a fluorine resin film such as PTFE film or PFA, a nonwoven fabric using a water-repellent resin, or the like is preferable.

  A sheet-like water supply body 128 is disposed behind the water-repellent layer 126. As this water supply body 128, it is a nonwoven fabric etc., for example.

  As described above, in this embodiment, the anode water adjusting unit is the water repellent layer 126 and the cathode water adjusting unit is the water repellent layer 130.

  The oxygen reduction cells stacked in order as described above are sandwiched and fixed by a pair of front and rear fixing members 132 and 134. The rear fixing member 132 disposed on the anode side has a rectangular parallelepiped shape, and has an exhaust port 136 having a rectangular cross section at the bottom. As shown in FIG. 3, the exhaust port 136 penetrates in the front-rear direction. On the other hand, the front fixing member 134 attached to the cathode side also has a rectangular parallelepiped shape, and has an opening 138 at the center. The opening 138 has a strip shape in which a plurality of slit-like holes penetrating in the vertical direction are arranged. The opening 138 corresponds to the position of the vent hole 112 of the container storage unit 104.

  The oxygen reduction unit 115 is comprised by the above member. The fixing member 132 and the fixing member 134 are fixed by several screws (not shown). The fixing member 132 and the fixing member 134 are formed of, for example, ABS resin that requires rigidity in order to prevent warping of each of the sandwiched members.

  In the oxygen reduction unit 115, as shown in FIG. 3, the gasket 131 having the water repellent layer 130, the cathode current collector 124, and the side surfaces of the cathode 120 are sealed and packed with resin.

  The thickness in the front-rear direction of the fixing member 132 and the fixing member 134 is, for example, 10 mm, the thickness of the water supply body 128 is, for example, 0.2 mm, the thickness of the water-repellent layer 126 and the water-repellent layer 130 is, for example, 0.2 mm, The thickness of the gasket 131 is 0.2 mm, the thickness of the anode 118 is 0.25 mm, the thickness of the electrolyte membrane 116 is 0.2 mm, the thickness of the cathode 120 is 0.25 mm, and the thickness of the insulator 126 is 0, for example. The thickness of the anode current collector 122 and the cathode current collector 124 is 0.5 mm, for example.

(4-2) Case 114
The oxygen reduction unit 115 described above is accommodated in a box-shaped case 114. The case 114 will be described with reference to FIGS. 5 is a front view of the case 114, FIG. 6 is a rear view, and FIG. 7 is a longitudinal sectional view.

  Case 114 is formed of a heat insulating member. For example, the thickness is 5 mm. The case 114 includes a unit storage portion 140 for storing the oxygen reduction unit 115 and a water passage portion 142 provided on the side of the unit storage portion 140. The cylindrical water passage part 142 is provided with a water purification part 144 made of an ion exchange resin. Condensed water generated in the R-eva 28 is supplied from the water supply pipe 152 to the upper surface of the water passage portion 142 by the pump 146 through the hose 56. The water purified by the ion exchange resin water purifier 144 flows from the bottom surface of the water passage 142 into the lower part of the unit housing 140. As shown in FIG. 7, the lower part of the unit storage part 140 has a water holding part 148 that is inclined downward toward the center, and the water flowing out from the water purifying part 144 accumulates in the water holding part 148.

  As shown in FIG. 6, a diffusion port 150 for diffusing oxygen generated by the oxygen reduction unit 115 and a drain pipe 154 for allowing the water overflowing from the water holding unit 148 to flow outside are connected to the back surface of the case 114. Has been. The water from the drain pipe 154 is drained to an evaporating dish, for example.

  A water supply body 128 that hangs down from the oxygen reduction unit 115 is immersed in the water accumulated in the water holding unit 148. The water holding unit 148 may also serve as the water supply body 128 by holding water in a water holding member such as a sponge. As a water supply method, water may be retained by dropping water from above or by carrying moisture in the air with a deliquescent substance.

  The fixing member 134 of the oxygen reduction unit 115 is fixed to the back surface of the container storage unit 104, and the case 114 is also fixed to the container storage unit 104.

(5) Refrigeration cycle Next, the structure of the refrigeration cycle will be described with reference to FIG.

  In the refrigeration cycle, a condenser 60 and a three-way valve 62 are connected in order from the discharge side of the compressor 24. A refrigeration capillary tube 64 and an R-eva 28 are connected to one outlet of the three-way valve 62. The other outlet of the three-way valve 62 is connected to the freezing capillary tube 66 and the F-evapor 32. Thereafter, the refrigerant flow path becomes one, and reaches the suction side of the compressor 24 through the suction pipe 68. The refrigerant is compressed by the compressor 24 to be changed into a high-temperature and high-pressure gaseous refrigerant, and becomes a liquid state while releasing heat from the condenser 60. The liquid refrigerant is sent to the refrigeration capillary tube 64 or the freezing capillary tube 66 by the three-way valve 62, where it is depressurized so as to be easily vaporized, and then vaporized by the R EVA 28 or F EVA 32, and from the surroundings. Cold is generated by taking away heat.

(6) Electrical configuration of refrigerator 10 Next, the electrical configuration of the refrigerator 10 will be described based on the block diagram of FIG.

The control plate 26 is provided with a control unit 70 made of a microcomputer. The control unit 70 is connected to the compressor 24, the three-way valve 62, the R fan 30, the F fan 34, the oxygen reducing device 102, the pump 103, the R sensor 31, the F sensor 35, and the CO ₂ sensor 72.

  This control part 70 controls the refrigerating cycle demonstrated above using the inverter motor of the compressor 24, and the three-way valve 62, the refrigerator compartment 14 is 2 degreeC-4 degreeC, the vegetable room is 5 degreeC-7 degreeC, and a chilled room 44 is controlled to 0 ° C. to 1 ° C., and the small freezer 18, ice making chamber 19 and freezer 20 are controlled to −20 ° C. to −25 ° C.

(7) Operation State of Oxygen Reduction Device 102 The operation state of the oxygen reduction device 102 will be described with reference to FIGS.

  First, as shown in FIG. 8, when the vegetable compartment 16 is cooled, the door 16 a of the vegetable compartment 16 is closed, and the oxygen-reducing chamber 106 is housed in the container housing portion 104 for the oxygen-reducing chamber 100. . When the oxygen reduction container 106 is stored in the container storage portion 104, the inside of the oxygen reduction chamber 100 becomes a sealed space by the gasket 110 which is a sealing means.

  Next, as shown in FIG. 7, the pump 146 supplies the defrost water generated by the R EVA 28 to the upper part of the water passage part 142 via the hose 56 and the water supply pipe 152. The supplied water flows out from the bottom of the water passage portion 142 through the water purification portion 144 inside the water passage portion 142 and accumulates in the water holding portion 148. The water supply body 128 immersed in the water of the water holding unit 148 sucks up the accumulated water.

Next, as shown in FIG. 8, when the food 58 is stored in the oxygen reduction chamber 100, the food 58 breathes and emits CO ₂ . Then, the CO ₂ sensor 72 serving as food storage detection means detects the CO ₂ , and the control unit 70 starts energization of both the current collectors 122 and 124 or increases the value of the energized current. To do. Further, the internal temperature of the oxygen-reducing chamber 100 is higher than the internal temperature 1 ° C. of the chilled chamber 44. That is, since the oxygen-reducing chamber 100 is provided inside the vegetable compartment 16, it becomes the same as the inside temperature of the vegetable compartment 16, for example, 5 ° C to 7 ° C. As a result, the food 58 such as vegetables stored therein can prevent a low-temperature failure due to the internal temperature being too low.

  Next, as shown in FIGS. 3 and 4, the air in the oxygen reduction container 106 is supplied through the vent 112 of the oxygen reduction chamber 100 and the opening 138 of the fixing member 134, and the current collectors 122 and 124 are connected to each other. Since it is energized, oxygen is reduced from the air that flows in, and the oxygen reduction chamber 100 becomes the CA storage chamber. In the anode 118 and the cathode 120, the oxygen reduction reaction as shown in the following formulas (1) and (2) is performed.

Anode: 2H ₂ O → O ₂ + 4H ⁺ + 4e ⁻ (1)

Cathode ... O ₂ + 4H ⁺ + 4e ⁻ → 2H ₂ O (2)

Explaining this oxygen reduction reaction formula, water vapor that has passed through the water-repellent layer 126 from the water supply body 128 is electrolyzed at the anode 118 to form hydrogen ions, which move through the electrolyte membrane 116 and reach the cathode 120. Then, it reacts with oxygen inside the oxygen-reducing chamber 100 to generate water and consumes oxygen. Thereby, oxygen reduction is performed inside the oxygen reduction container 106, and the food 58 can be stored in CA.

  Next, as shown in FIGS. 3, 6, and 7, oxygen generated at the anode 118 of the oxygen reduction unit 115 first passes through the exhaust port 136 of the fixing member 132 and then diffuses from the diffusion port 150. .

  Here, the water-repellent layer 126 suppresses the amount of water that moves from the water supply body 128 to the anode 118 and does not move the water-repellent layer 126 and allows only gaseous water vapor to pass therethrough. This prevents liquid water from entering the anode 118 and prevents flooding.

  Further, by providing the water repellent layer 130 in front of the cathode 120, water is generated in the cathode 120 when the oxygen reducing chamber 100 is deoxygenated. This water is pure water produced by a chemical reaction. The generated water accumulates at the cathode 120 and more water than the anode 118, so that the water returns to the anode 118 through the electrolyte membrane 116 (back diffusion phenomenon). Therefore, pure water can be supplied to the anode 118 side, and the supply amount to the water supply body 128 can be reduced.

  Note that the control unit 70 controls the oxygen concentration by the oxygen reduction device 102 so that it is not less than 10%. This is effective even when the oxygen concentration of 10% is sufficient for the preservation of the food 58 such as vegetables, and a large amount of power is required to reduce the concentration to 10% or less. This is because the influence on the human body is undesirable when breathing.

  Next, as shown in FIG. 9, when the door 16a of the vegetable compartment 16 is pulled forward, the vegetable container 48 also moves forward. However, since the oxygen reduction container 106 of the oxygen reduction chamber 100 is stored in the container storage unit 104, the oxygen reduction state is maintained.

  Next, as shown in FIG. 10, when the oxygen reduction container 106 of the oxygen reduction chamber 100 is pulled forward, the oxygen reduction state is released and the food 58 stored in the oxygen reduction container 106 can be taken out.

(8) Effect According to this embodiment, since the case 114 of the oxygen reduction device 102 has heat insulation properties, electrolysis is performed in the oxygen reduction unit 115, and heat generated thereby can be transmitted to the vegetable compartment 16. Absent. Therefore, the internal temperature of the vegetable compartment 16 is not increased.

  In addition, since the diffusion port 150 is provided at the lower back of the case 114, the heat generated by the electric reaction is accumulated at the upper part of the unit housing portion 140, and the heat is not transmitted to the outside from the diffusion port 150 at the lower part. Further, since oxygen is a molecule having a molecular weight of 32 and is expected to be heavier than air and diffuse downward, it is efficient to provide the exhaust port 136 and the diffusion port 150 below the oxygen reduction device 102.

  Further, since the oxygen reduction unit 115 is surrounded by the heat insulating case 114, the inside of the case 114 is warmed by the heat of electrolysis, and the water sucked up by the water supply body 128 is easily evaporated, and stable hydrogen ions Supply becomes possible.

  Further, since the water holding portion 148 is provided inside the case 114, no special parts or space for storing water is required.

  Further, since the side surface of the cathode 120 is sealed with the resin 156, air in the oxygen reduction container 106 is supplied through the vent 112 and the opening 138, and only oxygen can be converted into water from the air.

  Further, since the electrolyte membrane 116, the anode 118, the cathode 120, the current collectors 122 and 124, and the water repellent layers 126 and 130 are sandwiched by the fixing member 132 and the fixing member 134, these members can be fixed integrally. Although each member is a thin layer, since it is clamped by the fixing members 132 and 134 from both sides, uniform contact of each member can be ensured without warping back. In particular, the fixing member 132 and the fixing member 134 have a strong rigidity at the portion that hits each member, and can prevent warping of each member. Therefore, a uniform contact area can be ensured.

  Further, since the opening 138 of the fixing member 134 on the cathode 120 side has a strip shape, the strength for pressing the cathode 124 can be maintained as it is, and an opening area through which oxygen passes can be secured.

  Moreover, since the water purifying part 144 of the ion exchange resin is provided in the water passage part 142, the water supplied to the water supply body 128 can remove the influence due to the water quality of the defrost water, and the deterioration of the oxygen reduction apparatus 102 can be prevented. Can be prevented.

  Further, the oxygen-reducing chamber 100 is provided inside the vegetable compartment 16 so that the temperature inside the oxygen-reducing chamber 100 is equal to or higher than the temperature inside the chilled chamber 44. Therefore, the internal temperature becomes 5 ° C. to 7 ° C., and the food 58 such as vegetables stored in the oxygen reduction chamber 100 does not cause a low temperature failure. On the other hand, the chilled chamber 44 is normally controlled at a temperature of about 1 ° C., and can store meat and fish for a long time without freezing.

When the food 58 is stored in the hypoxic chamber 100, the food 58 breathes and discharges CO ₂ , so the CO ₂ sensor 72 detects the CO ₂ , and the control unit 70 detects both the current collectors 122 and 124. Is energized, or the energized current value is increased. Thus, power can be saved until the food 58 is stored.

  In addition, by providing the water repellent layer 126, water can be prevented from entering the anode 118 from the water supply body 128 and only water vapor can be transmitted, so that the flooding phenomenon can be prevented.

  In addition, since a polymer film is used as the water repellent layer 126, even if there is an impurity such as a mineral in the supplied water, a phenomenon that the electrolyte membrane 116 is deteriorated can be prevented by blocking. Further, when the polymer film is used, the water repellent performance is not deteriorated and a long life can be obtained.

  Further, by providing the water repellent layer 130, the water generated at the cathode 120 flows to the anode 118, whereby pure water can be supplied to the anode 118, and the supply amount from the water supply body 128 can be reduced. . Furthermore, since water generated in the cathode 120 does not return into the oxygen reduction chamber 100, it is possible to prevent the food 58 from being accelerated by being cooled and condensed in the oxygen reduction chamber 100.

  Further, since defrosted water generated from the R-eva 28 is used, it is not necessary for the user to add water to the water supply body 128 at a constant cycle, and the user forgets to add water. Does not promote deterioration. That is, considering the deterioration of the oxygen reduction device 102, the supplied liquid should be close to pure water, and chlorine and minerals promote deterioration in tap water available in any household. On the other hand, defrost water is water formed by cooling water vapor, and although some metal components are dissolved on R EVA 28, impurities are considerably reduced compared with tap water. Deterioration of the device 102 can be prevented. Moreover, by supplying defrost water to the oxygen reduction apparatus 102, it is led to the evaporating dish provided in the machine room 22 to be converted into water vapor by heat, and the amount released can be reduced.

  Further, the oxygen reduction chamber 100 is fixed inside the vegetable chamber 16, and an oxygen reduction device 102 is fixed to the back surface of the oxygen reduction chamber 100. Therefore, even if the door 16a of the vegetable compartment 16 is opened, the oxygen reduction chamber 100 remains fixed. Then, when taking out the food 58 stored with reduced oxygen, the food 58 in the oxygen reduction container 106 can be taken out by opening the door 108. With such a structure, it is not necessary to move the electrical wiring, the water supply pipe 152, and the drain pipe 154 that are connected to the current collectors 122 and 124 of the oxygen reduction device 102, and the oxygen reduction device 102 and the oxygen reduction device 102 are not moved. The hermetic seal structure of the chamber 100 can be simplified, and the degree of freedom in design increases.

(9) Modification 1
A first modification of the first embodiment will be described with reference to FIG.

  In the first embodiment, only the cathode 120 side is covered with the resin 156, but in this modified example, the parts and side surfaces between the fixing member 132 and the fixing member 134 are all sealed with the resin 156.

  Thereby, there is no inflow of oxygen from other parts, and the oxygen in the oxygen reduction container 106 can be reduced more reliably by the oxygen reduction unit 115.

(10) Modification 2
Next, a second modification of the first embodiment will be described with reference to FIG.

  In the above embodiment, the electric wires 158 and 160 connected to the projecting piece of the anode current collector 122 and the projecting piece of the cathode current collector 124 have penetrated the case 114, but gas cannot enter and exit from this portion. It was.

  However, in this modified example, vents 162 and 164 are provided in a portion through which the electric wire 158 connected to the anode current collector 122 and the electric wire 160 connected to the cathode current collector 124 pass, and the vents 162 and 164 are connected to the electric wire. It may be larger than the outer diameters of 158 and 160 so that oxygen can diffuse from the vents 162 and 164.

Embodiment 2

  Next, the oxygen reduction apparatus 200 of the refrigerator 10 of Embodiment 2 is demonstrated based on FIGS. The difference between the present embodiment and the first embodiment is an oxygen reduction device 200 and a water supply device 300 that supplies water to the oxygen reduction device 200. Hereinafter, it demonstrates in order.

(1) Oxygen reduction device 200
In the oxygen reduction device 200, an oxygen reduction unit 202 is housed inside a case 204 having heat insulation properties. The oxygen reduction unit 202 will be described with reference to FIGS. 15 is a longitudinal sectional view of the oxygen reduction device 200, FIG. 16 is an exploded perspective view of the oxygen reduction unit 202, and FIG. 17 is an exploded perspective view of the oxygen reduction device 200. In FIGS. 15 to 17, the thickness of each member is thin, but the thickness is enlarged and described for easy understanding. Further, the description of the same members as those in the first embodiment is omitted.

  An electrolyte membrane 206 is provided in the vertical direction, an anode 208 is provided at the rear of the electrolyte membrane 206, and a cathode 210 is provided at the front of the electrolyte membrane 206. The cathode 210 is a laminate of a carbon catalyst and carbon paper. Further, platinum catalyst is supported on the anode 208 and the cathode 210, respectively. The electrolyte membrane 206, the anode 208, and the cathode 210 are integrally joined using a hot press or the like. Behind the anode 208. A positive-side anode current collector 212 is provided, and a cathode current collector 214 is provided in front of the cathode 210. Both current collectors 212 and 214 have slit-like openings 216 and 218, respectively, through which gas passes. The anode current collector 212 applies positive current to the anode 208, and the cathode current collector 214 performs negative current to the cathode 210. Both current collectors 212 and 214 are energized from electric wires (not shown). In addition, an insulator 220 is provided between the current collectors 212 and 214 in order to prevent the current collectors 212 and 214 from contacting each other. The insulator 220 has a frame shape, and the electrolyte membrane 206, the anode 208, and the cathode 210 are accommodated therein.

  A sheet-shaped water supply body 222 is disposed behind the anode current collector 212 on the anode 208 side. As this water supply body 222, it is a nonwoven fabric etc., for example. Further, the water supply body 222 has a sheet shape that is sucked up by the surface tension of water.

  A plate-like spacer 211 is disposed between the current collector 212 and the water supply body 222. The spacer 211 has a plurality of slit-shaped openings 213. The spacer 211 has a thickness of 1 mm, and forms a certain space A between the current collector 212 and the water supply body 222.

  The oxygen reduction cells stacked in order as described above are sandwiched and fixed by the front and rear pair of rear fixing members 224 and the front fixing member 226. The rear fixing member 224 disposed on the anode side has a storage recess 228 for storing the stacked members, and a groove 230 in which the protruding pieces of the current collectors 212 and 214 protrude is provided at the upper part. In addition, a slit-like opening 232 through which gas passes is opened at the center of the rear fixing member 224.

  The front fixing member 226 attached to the cathode side has a plate shape, and has a slit-like opening 234 through which gas passes in the center. As shown in FIG. 15, the slit-like opening 234 is inclined so as to become narrower as it is later, unlike the cross-sectional area on the front side and the cross-sectional area on the rear side. This is to make it easier to send air to the cathode current collector 214.

  The rear fixing member 224 and the front fixing member 226 are screwed with screws (not shown). A unit in which these members are integrated is referred to as an “oxygen reduction unit 202” in the second embodiment. Note that the projecting pieces of the current collectors 212 and 214 protrude from the upper part of the oxygen reduction unit 202, and the water supply body 222 hangs from the lower part.

(2) Case 204
The oxygen reduction unit 202 described above is accommodated inside a case 204 having a box-like heat insulating property. The case 204 will be described with reference to FIGS. 15 and 17.

  The case 204 includes a rectangular parallelepiped front case 236, a rear case 238, a front case 236, and a frame-shaped middle case 240 sandwiched between the rear case 238. A front case 236 is arranged on the cathode side of the oxygen reduction unit 202, a rear case 238 is arranged on the anode side, and the front case 236, the rear case 238, and the middle case 240 are not shown in the state in which the oxygen reduction unit 202 is stored. Screwed.

  The front case 236 will be described with reference to FIGS. A square-shaped reaction recess 244 is provided at the center of the rear surface of the front case 236 having heat insulation properties. Further, a groove-shaped upper flow path 246 is provided from the upper surface of the reaction recess 244 toward the upper surface of the front case 236, and an upper vent hole 248 is opened on the upper surface of the front case 236. Further, a groove-like lower flow path 250 is provided downward from the lower surface of the reaction recess 244, and a lower vent hole 252 is opened on the lower surface of the front case 236. As shown in FIG. 15, a rectangular parallelepiped space is created between the cathode current collector 214 on the cathode side and the front wall of the front case 236 by the reaction recess 244. Hereinafter, this space is referred to as “reaction space B”.

  Next, the middle case 240 will be described with reference to FIGS. 15 and 17. A front fixing member 226 of the oxygen reduction unit 202 is housed in the central portion 242 of the frame-shaped middle case 240.

  Next, the rear case 238 will be described with reference to FIGS. A storage recess 254 that can store the rear fixing member 224 of the oxygen reduction unit 202 is provided at the center of the front surface of the rear case 238, and the current collectors 212 and 214 of the current collectors 212 and 214 are arranged from the storage recess 254 toward the upper surface of the rear case 238. Grooves 256 and 258 from which the protruding pieces protrude are provided. An exhaust recess 260 is further provided on the rear surface of the storage recess 254, and the lower surface of the exhaust recess 260 has an inclined surface so as to approach each other and communicates with the exhaust port 262. The exhaust port 262 opens on the lower surface of the rear case 238.

  The case 204 in which the oxygen reduction unit 202 is stored is attached to the rear surface of the container storage unit 104 of the oxygen reduction chamber 100. This attachment method will be described with reference to FIG.

  At the center of the rear surface of the container storage unit 104, a cubic storage holding unit 264 projects toward the storage side. The storage case 264 stores the front case 236 of the case 204 from the rear. Therefore, the upper hole 266 and the lower hole 268 are opened at positions corresponding to the upper ventilation hole 248 and the lower ventilation hole 252 that are opened on the upper surface and the lower surface of the front case 236.

  Since the case 204 protrudes from the rear surface of the container storage unit 104, the cover 270 is covered so as to cover the protruding portion. The cover 270 is made of a synthetic resin and has a shape that covers the entire rear case 238 of the case 204. The cover 270 is provided with current collector openings 278 and 278 through which both current collectors 212 and 214 protrude. In addition, an exhaust port 280 communicating with the exhaust port 262 of the rear case 238 is opened.

  Instead of the structure in which the oxygen storage container 106 is stored in the container storage unit 104, the container storage unit 104 itself may be configured with an oxygen reduction container in which food is stored.

(3) Water supply device 300
Next, the water supply apparatus 300 is demonstrated based on FIG. 15 and FIG.

  The water supply apparatus 300 has a water supply main body 302, and the water supply main body 302 is a horizontally long rectangular parallelepiped box. The water supply main body 302 is vertically divided by a partition wall 304 inside thereof, and an upper portion constitutes a water purification compartment 306 and a lower portion constitutes a suction section 308. A water supply pipe 152 is connected to the upper surface of the left end portion of the water supply main body 302, that is, the upper surface of the water purification section 306. This water supply pipe 152 is fed with defrosted water generated from the R EVA 28 of the refrigerator 10 by the pump 146.

  As shown in FIG. 19, the partition wall 304 is inclined downward from a portion to which the water supply pipe 152 is connected, and a water supply hole 310 leading to the suction section 308 is formed at the right end portion. A purified water section 312 made of an ion exchange resin is provided inside the purified water section 306. By providing this water purification unit 312, it is possible to remove the influence of the quality of defrost water supplied from the R EVA 28, and to prevent the oxygen reduction unit 115 from deteriorating. That is, the defrost water is frost adhering to the R EVA 28 and is collected in the drain pan, and therefore contains metal ions. Therefore, since there is a possibility of promoting the hydrolysis of the synthetic resin fibers constituting the water supply body 222, the provision of the water purification unit 312 can remove the influence of the quality of the defrost water.

  The suction section 308 has a water storage part 314 for storing the water supplied from the water supply hole 310. Further, a drain pipe 154 is provided at the left end of the suction section 308. A partition wall 316 is provided between the drain pipe 154 and the water storage unit 314. The defrost water supplied from the water supply hole 310 is accumulated in the water storage unit 314. The water storage unit 314 is recessed at the center, and the lower part of the water supply body 222 of the oxygen reduction unit 202 described above is immersed, and the water supply body 222 sucks up the accumulated water. When the amount of water in the water storage unit 314 increases and exceeds the partition wall 316, the water is drained from the drain pipe 154 to an evaporating dish (not shown). In the water supply main body 302 that is a horizontally long rectangular parallelepiped, the suction section 308 projects forward from the water purification section 306, and the water supply body 222 projects from the ceiling surface that projects forward from the suction section 308.

(4) Operation State of Oxygen Reduction Device 200 The operation state of the oxygen reduction device 200 will be described with reference to FIGS.

  The oxygen reduction device 200 is supplied from the water supply device 300 to the water supply body 222 in the same manner as the oxygen reduction device 102 of the first embodiment, and the water supplied to the water supply body 222 is expressed by Expression (1) and Expression (2). Due to the reduced oxygen reaction, the oxygen reduction chamber 100 is reduced in oxygen.

  By the way, when the water supply body 222 and the anode are in direct contact with each other, ion contamination components such as Ca (calcium) in the supplied water cause a reaction in the electrolyte membrane 206 and deteriorate the performance of the electrolyte membrane 206. There is. For this reason, the supply of water is preferably pure water or ion-exchanged water. As a method for supplying such pure water or ion-exchanged water to the current collector 212 on the anode side, there is a method in which water is once vaporized and supplied as water vapor. However, heating with a heater or the like for vaporization increases power consumption and is not appropriate. Further, as in the first embodiment, a method of inserting a water-repellent water-repellent layer 126 such as a PTFE film that allows water vapor to pass but does not allow liquid water to pass between the water supply body 222 and the current collector 216 is also conceivable. There is also a possibility of deterioration of the water repellent layer 126.

  Therefore, in the present embodiment, a space is provided between the water supply body 222 and the anode-side current collector 212 so that liquid water does not contact the current collector 212. In this method, water heated by the heat generation of the oxygen reduction unit 202 becomes water vapor, and can react by contacting the oxygen reduction cell. Increasing the voltage applied to the oxygen reduction cell in order to increase the reaction rate is more effective when directly affected by the oxygen reduction cell, for example, the amount of water vapor increases because the temperature of the oxygen reduction cell itself increases.

  In this embodiment, in order to form a space between the water supply body 222 and the anode-side current collector 212, a water-repellent and insulating spacer 211 is disposed. For the operation of the oxygen reduction cell, contact between the anode 208 and the current collector 212 on the anode side is important. If the resistance increases due to poor contact, the operation of the oxygen reduction cell becomes insufficient. For this reason, by transmitting the tightening pressure by the spacer 211 rather than simply providing a space, a more stable operation of the oxygen reduction cell can be ensured. In this case, the space between the water supply body 222 and the current collector on the anode side is formed by a slit-shaped opening 213 opened in the spacer 211. In addition, this opening part 213 should just be able to form space, and may be not only a slit form but a grid | lattice form. Since the spacer 211 is water repellent, liquid can be prevented from entering from the water supply body 222. Further, since the spacer 211 that is in close contact with the current collector 212 is insulative, electric energy is correctly transmitted from the current collector 212 on the anode side to the anode 208 without an increase in resistance due to the current collector 212.

  By the way, the thickness of the spacer 211 is a factor that directly determines the size of the space between the water supply body 222 and the current collector 212. Therefore, the table of FIG. 21 shows the results of the test conducted by the applicant to determine whether or not water from the water supply body 222 has entered the oxygen reduction cell by changing the thickness of the spacer 211.

  As shown in the table of FIG. 21, when the thickness of the spacer 211 was less than 1.0 mm, water entered, and when it was 1.0 mm or more, water did not enter. Therefore, the thickness of the spacer 211 is preferably 1.0 mm or more. However, if it is too thick, the thickness of the oxygen-reducing unit 202 becomes large, so 3.0 mm or less is preferable.

  In the present embodiment, the spacer 211 serves as an anode water adjusting unit.

  In addition, the hypoxic reaction is exothermic, and the higher the temperature, the more efficient the catalyst, and the reaction occurs at a lower voltage. On the other hand, if the oxygen reduction device is entirely covered with the heat insulating material, contact with air is lost and the oxygen reduction reaction is stopped. Further, in a structure in which air does not move, water generated at the cathode accumulates in the vicinity thereof, causing a flooding phenomenon that interferes with contact with air.

  Therefore, first, in this embodiment, the oxygen reduction unit 202 is covered with a heat insulating case 204, the temperature generated by the oxygen reduction reaction is maintained, the efficiency of the catalyst is improved, and the reaction is performed at a lower voltage. In particular, since the portion of the cathode 210 is entirely covered by the front wall of the front case 236, heat insulation can be further maintained.

  Secondly, in the present embodiment, even if the heat insulation as described above is maintained, a reaction space B is formed on the cathode 210 side by the reaction recess 244, and the upper ventilation hole 248 of the front case 236 is formed in the reaction space B. And air is supplied from the lower vent hole 252. That is, air containing oxygen is supplied from the lower hole 268 to the reaction space B formed by the reaction concave portion 244 through the lower vent hole 252 and the lower flow path 250, and is reduced by the expressions (1) and (2). Can promote oxygen reaction.

  Thirdly, in the present embodiment, water generated by the oxygen reduction reaction is converted into water vapor by the heat generation, and is discharged from the reaction space B into the oxygen reduction container 106 through the upper flow path 246, the upper ventilation hole 248, and the upper hole 266. Is done. Therefore, the flooding phenomenon does not occur. In particular, since the surrounding air is warmed by the heat generation of the oxygen reduction unit 202, the air easily escapes from above into the upper vent hole 248, and the water vapor generated by the oxygen reduction reaction also easily escapes.

  Fourth, in the present embodiment, by providing the vent holes 248 and 252 above and below the reaction space B, the flow of air from the bottom to the top becomes smooth, and air enters from the bottom to warm the oxygen reduction unit 202. Ascending airflow can be created in which the air containing water vapor generated here is discharged upward.

  In addition, when liquid water is generated, the opening 234 of the front fixing member 226 is inclined in the direction of gravity, and the liquid water is not easily collected from the hole 252. The front fixing member 226 may have water repellency.

(5) Effect According to the present embodiment, the spacer 211 is disposed between the anode-side current collector 212 and the water supply body 222, and the spacer 211 is provided with the opening 213, whereby the water supply body 222 and the current collector are disposed. A space is formed between the body 212 and the body 212. Therefore, the liquid water from the water supply body 222 does not contact the current collector 212, and the water heated by the heat generation of the oxygen reduction cell becomes water vapor, and can react by contacting the oxygen reduction cell. In order to increase the reaction rate, the voltage applied to the current collectors 212 and 214 of the oxygen reduction cell is increased, so that the temperature of the oxygen reduction cell itself increases and the amount of water vapor increases. The effect is more likely to appear.

  The flooding phenomenon is a phenomenon in which water is liquefied on the cathode side and shuts off the reaction gas. One of them is that when water is supplied to the anode with liquid water, the water moves through the electrolyte membrane. This is a phenomenon that reaches the cathode and inhibits the reaction between hydrogen ions and oxygen at the cathode. However, by supplying water to the anode 208 with water vapor as in the present embodiment, liquid water moves through the electrolyte membrane 206 and reaches the cathode 210, and the reaction between hydrogen ions and oxygen at the cathode 210 is performed. There is no hindrance, no flooding phenomenon occurs, and the performance of the oxygen reduction cell can be maintained.

  In addition, the clamping pressure from the current collector 212 to the anode 208 is transmitted by the spacer 211, and the anode 208 and the current collector 212 are completely brought into contact with each other, so that resistance due to poor contact does not increase, and a more stable reduction can be achieved. The operation of the oxygen cell can be secured. Further, since the spacer 211 is water-repellent, liquid water can be prevented from entering. Further, since the spacer 211 is insulative, resistance due to the current collector 212 is prevented from increasing, and electric energy is correctly transmitted to the oxygen reduction cell.

  Further, by setting the thickness of the spacer 211 to 1 mm or more, liquid water can be prevented from entering the oxygen reduction cell from the water supply body 222.

  The spacer 211 has a space formed by slit-shaped or lattice-shaped openings 213, and can transmit pressure to the current collector 212 at the edge of the openings 213. Therefore, rather than creating one large space, it is possible to transmit pressure and form a space by providing a plurality of small openings 213 and forming a large number of small spaces.

  In addition, since the water supply body 222 is a sheet that is sucked up using the surface tension of water and capillary action, considering the contact between the current collector 222 and the oxygen-reducing cell, the water supply body 222 should be as thin as possible. It is easy to convey to the current collector 212, and a stable operation of the oxygen reduction cell can be extracted. Moreover, the thin water supply body 222 has the merit that the thickness of the oxygen reduction unit and 202 can be reduced, and the installation location is not selected.

  In addition, since the oxygen reduction unit 202 is covered with the heat insulating case 204, the temperature can be increased by heat generated by the oxygen reduction reaction of the oxygen reduction unit 202, and the function of the catalyst can be further improved. In addition, since the front of the cathode 210 is covered by the front case 236 and the reaction space B is formed by the reaction recess 244, the cathode 210 can come into contact with air, and heat insulation due to the covering improves the efficiency of the catalyst. Can be raised.

  Further, the front case 236 has an upper vent hole 248 and a lower vent hole 252 that open and communicate with the reaction space B, so that the air flow is smooth and oxygen-containing air is easily supplied to the cathode 210. In particular, since a plurality of air holes 236 and 238 are provided, air circulation can be ensured.

  Further, since the upper vent hole 248 and the lower vent hole 252 communicate with the inside of the oxygen reduction chamber 100, the air inside the oxygen reduction chamber 100 can be reliably supplied.

  Further, since the cross-sectional areas of the upper ventilation hole 248 and the lower ventilation hole 252 are smaller than the area of the plurality of openings 234 opened in the front fixing member 226, air can be reliably circulated, and air can be supplied to the cathode 210. Can supply.

  In addition, since the width in the left-right direction of the front fixing member 226 of the oxygen reduction unit 202 is wider than the reaction recess 244, air can be easily supplied. Furthermore, since the width of the reaction recess 244 is wider than the width of the upper flow path 246 and the lower flow path 250, air easily diffuses inside the reaction recess 244.

  Further, the strip-shaped opening 234 of the front fixing member 226 is inclined so as to become narrower toward the rear, unlike the cross-sectional area on the front side and the cross-sectional area on the rear side. Easy to send.

  Further, in the upper flow path 246 inside the front case 236, the water vapor discharged upward by the ascending airflow decreases from the oxygen reduction unit 202, and as a result, the temperature drops, so that water droplets form inside the front case 236 and cause condensation. Sometimes. However, even if such condensation occurs, the upper flow path 246 and the lower flow path 250 are formed in a straight line, so that they do not collect in the reaction recess 244 of the oxygen reduction unit 202 and flow out of the lower vent hole 252 and are discharged. Is done.

(6) Modification 1
A first modification of the second embodiment will be described.

  In the above embodiment, the thickness of the spacer 211 is uniform, but in this modified example, only the top, bottom, left, and right edges of the four openings 213 in the spacer 211 are replaced with other portions (for example, the surrounding portions of the spacer 211). Each frame is thicker than (thickness) and formed into a frame shape. The reason is as follows. It is necessary to press the spacer 211 against the current collector 212 by screwing the front fixing member 226 and the rear fixing member 224. However, since the water supply body 222 needs to secure liquid water, it is difficult to transmit the pressure to the current collector 212 by the water supply body 222. This is because the material of the water supply body 222 swells and softens to absorb water. However, as in the first modification, by increasing the thickness of the edges of the four openings 213 in a frame shape, pressure can be transmitted through the frame-shaped portion.

  As a further modification of the first modification, the four edge portions of the square spacer 211 may be thicker than the other portions to form a frame shape.

(7) Modification 2
A second modification of the second embodiment will be described.

  In this modified example, water in the air is collected and supplied by blending deliquescent substances into the water supplied to the water supply body 222.

That is, in the said embodiment, although water was supplied from the water supply apparatus 300, in this modification, the water | moisture content in the surrounding air is collected and supplied as water by mix | blending a deliquescent substance with the water supply body 222. FIG. Examples of deliquescent substances include citric acid (C ₆ H ₈ O ₇ ), sodium hydroxide (NaOH), potassium carbonate (K ₂ CO ₃ ), magnesium chloride (NgCL ₂ , calcium chloride (CaCL ₂ ). A deliquescent substance usually becomes an impurity of water because it dissolves in water, and is not suitable for a hypoxia reaction. However, when it can be supplied with water vapor as in the above embodiment, the impurity contains in the water. However, this deliquescent material can be applied regardless of the hypoxic reaction.

(8) Modification 3
A third modification of the second embodiment will be described.

  In the above embodiment, water is supplied to the water supply body 222 using defrost water. However, in this modified example, water is supplied from the tap and supplied to the water supply body 222. If it is tap water, the freedom degree of the installation position of the oxygen reduction apparatus 200 will increase, and there exists an effect that it is easy to design.

(9) Modification 4
Modification 4 of Embodiment 2 will be described with reference to FIG.

  In this modified example, as shown in FIG. 22, the lower surface continuing from the storage recess 244 to the lower flow path 250 is an inclined surface. As a result, water droplets due to condensation generated in the upper flow path 246 and the reaction recess 244 flow more reliably to the lower flow path 250.

(10) Modification 5
Modification 5 of Embodiment 2 will be described with reference to FIG.

  In this modified example, as shown in FIG. 23, an upper flow path 246 and a lower flow path 250 are provided between the front surface 236a and the rear surface 236b of the front case 236 in contact with the oxygen reduction unit 202, that is, at the center of the upper surface 236c. Provide. Thereby, the oxygen reduction unit 202 can be more reliably covered with the front case 236 having heat insulation properties, and the heat insulation effect can be enhanced. Therefore, the efficiency of the catalyst can be further increased.

(11) Modification 6
Modification 6 of Embodiment 2 will be described with reference to FIG.

  In this modified example, as shown in FIG. 24, a plurality of ribs 282 as turbulent flow generating means are provided in the lower flow path 250 provided in the front case 236. The ribs 282 are provided at different levels and inclined so that the air entering from the lower vent holes 252 causes turbulence of airflow (turbulent flow) by the ribs 282, and at the position of the reaction recess 244. The catalyst can be spread over the entire area, and the catalyst can be reacted more efficiently by air.

(12) Modification example 7
Modification 7 of Embodiment 2 will be described with reference to FIG.

  In this modified example, as shown in FIG. 25, the upper flow path 246 and the lower flow path 250 are shifted and arranged so as not to be in a straight line to generate turbulent flow. With such an arrangement, airflow turbulence (turbulent flow) occurs, and air can be distributed throughout the oxygen reduction unit 202.

(13) Modification 8
In the second embodiment, the vent holes communicating with the reaction space B are provided vertically, but the present invention is not limited thereto, and may be provided left and right, diagonally, or vertically and horizontally diagonally.

Embodiment 3

  Hereinafter, the oxygen reduction device 421 according to the third embodiment and the refrigerator 401 including the oxygen reduction device 421 will be described with reference to FIGS. 26 to 35.

  First, the refrigerator 401 will be described with reference to FIG. The refrigerator 401 includes a refrigerator main body 402 formed of a heat insulating box. The refrigerator main body 402 has a refrigerating chamber at an upper portion (not shown), and has a hypoxic chamber 403 at an intermediate portion in the vertical direction of the refrigerator main body 402.

  The hypoxic chamber 403 is provided for preserving articles to be preserved such as vegetables housed therein in a low temperature and low oxygen environment for a long period of time. The oxygen-reducing chamber 403 is partitioned by a container housing portion 404 that forms a part of the wall of the refrigerator main body 402 and whose outer surface is covered with a heat insulating material, and is not communicated with the refrigerator compartment or the like. The container storage unit 404 is opened on the front surface of the refrigerator main body 402. This opening is opened and closed by a door 405.

  A refrigerant pipe (not shown) is provided on the outer surface of the container storage unit 404. The container housing 404 is cooled to a temperature suitable for refrigeration of food by the refrigerant flowing through the refrigerant pipe. Thereby, it is possible to refrigerate food stored in the oxygen reduction chamber 403 formed of the internal space of the container storage unit 404.

  The door 405 has a configuration in which a heat insulating material is filled therein, and also serves as a front wall of the oxygen-reducing container 406 whose upper surface is opened, for example. The oxygen reduction container 406 is movable in the front-rear direction with respect to the oxygen reduction chamber 403. With the oxygen reduction container 406 pulled out to the front side, vegetables and the like can be taken in and out through the opened upper surface.

  In order to move the oxygen reduction container 406 smoothly, a rail 407, a fixed roller 408, and a movable roller 409 are used. The rails 407 are disposed in the oxygen reduction chamber 403 at two positions on the left and right in the width direction of the oxygen reduction chamber 403, and extend in the front-rear direction. A fixed roller 408 that contacts the oxygen reduction container 406 from below is fixed to the front end of each rail 407. The movable roller 409 is fixed to the lower surface of the rear end portion of the oxygen reduction container 406 and is guided by the rail 407.

  Accordingly, the oxygen reduction container 406 can be smoothly moved in the front-rear direction with the rotation of these rollers while being supported by the fixed roller 408 and the movable roller 409 from the lower side.

  An annular seal packing 410 is attached to the periphery of the door 405. With the door 405 closing the front opening of the container storage unit 404, the seal packing 410 is brought into close contact with the front surface of the refrigerator main body 402 to hold the oxygen reduction chamber 403 in a sealed state. The door 405 can also be a heat insulating door attached to the front surface of the refrigerator main body 402 so as to be rotatable by a hinge. For this reason, the oxygen reduction container 406 may be pivotally attached.

  For example, the freezer compartment 413 divided into three upper and lower stages is formed at the lowermost part of the refrigerator main body 402 independently of the oxygen reducing chamber 403. The front opening of the freezer compartment 413 is opened and closed by a heat insulating opening / closing door 14. A machine room 415 is formed on the back side of the refrigerator main body 402 and at the lower end. A compressor 416 is installed in the machine room 415. In the refrigerator main body 402, a cooler 417 and a fan 418 to which refrigerant is supplied by a compressor 416 are disposed, and a cover 419 that covers these from the front side is disposed. Cold air generated by the cooler 417 and the fan 418 is circulated to the freezer compartment 413.

  The refrigerant that has flowed out of the cooler 417 is sucked into the compressor 416 through the refrigerant pipe (not shown) attached to the outer surface of the container storage unit 404. The refrigerator main body 402 is formed with a recess 420 that is open on one side surface, for example, the back surface. The recess 420 is provided on the rear side of the oxygen reduction chamber 403. The recess 420 and the oxygen reduction chamber 403 are communicated with each other via a through hole 402a formed in a wall that partitions them.

  Next, the oxygen reduction device 421 will be described with reference to FIG. The oxygen reduction device 421 includes an oxygen reduction unit 422, a power source 424, a case 425, a voltmeter 427 as voltage detection means, a control unit 429, and the like.

  The oxygen reduction unit 422 includes an oxygen reduction cell 423, an electrode assembly 436, and a cathode current collector 429, which are elements of this unit. The oxygen reduction unit 422 is not limited to one, and a plurality of oxygen reduction units 422 may be provided.

  The oxygen reduction cell 423 includes an anode 430 that is an element of the oxygen reduction unit 422, a cathode 431, and an electrolyte membrane 435.

  As the electrolyte membrane 435, a polymer electrolyte membrane can be suitably used. One side surface of the anode 430 is joined to one side surface of the electrolyte membrane 435. A cathode 431 is bonded to the other side surface of the electrolyte membrane 435 by contacting a cathode catalyst layer 432 described later. Therefore, the electrolyte membrane 435 is sandwiched between the anode 430 and the cathode 431.

  An electrode assembly 436 is bonded to the other side surface of the anode 430, that is, the side surface not in contact with the electrolyte membrane 435. Therefore, the electrode assembly 436 is disposed with the anode 430 interposed between the electrolyte membrane 435 and the electrode assembly 436.

  The electrode assembly 436 includes an anode current collector 437 and a vaporization layer 438 that are elements of the oxygen reduction unit 422. The anode current collector 437 of the electrode assembly 436 forms one electrode of the oxygen reduction unit 422. The anode current collector 437 is joined to the side surface of the anode 430. The vaporization layer 438 of the electrode assembly 436 is joined to the anode current collector 437 on the opposite side of the anode 430 with the anode current collector 437 as a boundary. Therefore, the vaporization layer 438 is disposed with the anode current collector 437 sandwiched between the anode 430 and the vaporization layer 438. And in this embodiment, this vaporization layer 438 becomes an anode water adjustment part.

  Note that the electrode assembly 436 may be formed by bonding the vaporized layer 438 to the anode side surface of the anode current collector 437, contrary to the present embodiment. The electrode assembly 436 may be formed by bonding the vaporized layer 438 to both side surfaces of the anode current collector 437.

  When these electrode assemblies 436 are used, a water vapor permeability that allows only water vapor to permeate without passing liquid water between the vaporized layer joined to the anode side surface of the anode current collector 437 and the anode 430 is provided. The electrode assembly 436 may be disposed with the anode 430 interposed between the electrolyte membrane 435 and an electric insulating layer having the structure interposed therebetween. Thereby, compared with the structure in which the vaporized layer 438 is bonded to the anode 430 and the electrode assembly 436 is disposed, it is possible to avoid the possibility that the oxygen reduction cell 423 and the electrode assembly 436 are corroded. Therefore, the durability of the oxygen reduction device 421 can be ensured. The oxygen reduction device 421 of this embodiment that does not require such insulation measures is preferable in that it has no corrosion problem and is excellent in durability despite its small number of parts.

  A cathode current collector 429 that is an element of the oxygen reduction unit 422 is joined to the outer side surface of the cathode 431, that is, the side surface of a gas diffusion layer 434 described later that is not in contact with the porous layer 433 described later. The cathode current collector 429 forms the other electrode of the oxygen reduction unit 422. The cathode current collector 429 and the anode current collector 437 are electrically connected to a power source 424.

  The case 425 incorporates the oxygen reduction unit 422 configured as described above. The case 425 is formed by connecting a first case member 441 and a second case member 445 made of an electrical insulating material. The electrolyte membrane 435 of the oxygen-reducing cell 423 is sandwiched between the first case member 441 and the second case member 445. At the same time, the first case member 441 and the second case member 445 fasten the oxygen reduction unit 422 along the thickness direction. Thereby, the closeness at each joint surface is ensured.

  An anode chamber 442 is formed between the first case member 441 and the electrode assembly 436 covering the anode 430. A cathode chamber 446 is formed between the second case member 445 and the cathode current collector 429 that covers the cathode 431.

  The first case member 441 has a water intake port 443 and an oxygen outlet 444 that communicate with the anode chamber 442. The water intake 443 is provided at the lower end of the first case member 441. Water for electrolysis, for example, water (liquid) is introduced into the anode chamber 442 from a water supply means such as a water supply tank (not shown) connected to the water intake port 443. The water (liquid) supplied to the anode chamber 442 may be an acidic aqueous solution or the like.

  The oxygen outlet 444 is provided in the upper part of the first case member 441 and guides oxygen generated by water oxidation reaction (electrolysis reaction) at the anode 430 from the anode chamber 442 to the outside.

  The second case member 445 has an air intake port 447 and a drain port 448 that communicate with the cathode chamber 446. A plurality of air intake ports 447 are provided on the side wall portion of the second case member 445 facing the cathode 431, and introduces air (oxygen) used for the oxygen reduction reaction into the cathode chamber 446. The drainage port 448 is provided at the lower end portion of the second case member 445 and guides the water generated by the oxygen reduction reaction from the cathode chamber 446 to the outside.

  Next, each element of the oxygen reduction unit having the oxygen reduction cell 423 will be described in more detail.

  First, the anode 430 will be described. The anode 430 contains a catalyst (anode catalyst) having an ability to oxidize water vapor. The anode catalyst is preferably supported on a substrate.

As the anode catalyst, for example, a composite oxide of a conductive metal oxide and a matrix oxide can be used. As the conductive metal oxide may include, for example, ruthenium oxide (RuO?), Iridium oxide (IrO ₂₎ or the like. Examples of the composite oxide with the matrix oxide include titanium oxide (TiO ₂ ), tin oxide (SnO ₂ ), and tantalum oxide (Ta ₂ O).

The anode catalyst may be selected in consideration of its activity, durability, cost and the like. As the composite oxide that forms this catalyst, in addition to the above, for example, RuO ₂ —Ta ₂ O, RuO ₂ —IrO ₂ , RuO ₂ —IrO ₂ —TO ₂ , RuO ₂ —SnO ₂ , RuO ₂ —Ta ₂ O, IrO ₂ -Ta ₂ O, and the like can be given.

  The base material supporting the anode catalyst has a mesh structure, and is selected in consideration of conductivity, electrochemical stability, adhesion to the anode catalyst, and the like. For example, an expanded metal such as titanium, a punching metal, an etching metal or the like that has been used in the field of the electrolytic industry can be used as the base material. Such an electrode in which the surface of a base material made of titanium is coated with the composite oxide is called a dimensionally stable (DSA) electrode.

  The anode 430 can be manufactured by a technique such as a coating method, a dipping method, or a spray method. For example, a method for manufacturing the anode 430 by the dipping method will be described below. As a base material, a titanium expanded metal having a thickness of 100 μm and an aperture ratio of 30% is prepared.

First, this substrate is washed after being immersed in a 10% oxalic acid aqueous solution maintained at 80 ° C. for 1 hour. Thereby, the surface of a base material is roughened and activated. Next, the dipping process, the drying process, and the firing process are further repeated a plurality of times in the order of description on the base material. In the dipping step, the base material is dipped in a butanol solution in which tantalum oxide and iridium chloride having a molar ratio of Ta: I = 0.3: 0.7 are dissolved. In the drying step, the immersed substrate is dried in air at 60 ° C. for 10 minutes. In the firing step, the dried substrate is fired in air at 45 ° C. for 10 minutes. The anode 430 is manufactured through these steps. In this case, the catalyst carrying amount coated on the surface of the base material having a mesh structure is manufactured such that, for example, a composite oxide of iridium oxide (IrO ₂ ) -tantalum oxide (Ta ₂ O) is 0.01 mg / cm ^2. Is done. In this adjustment, the amount of catalyst supported can be determined from the change in mass of the manufactured anode.

  The cathode 431 will be described. The cathode 431 is preferably composed of a cathode catalyst layer 432, a conductive porous layer (MPL) 433, and a gas diffusion layer (GDL) 434.

  The cathode catalyst layer 432 is formed in a sheet shape and joined to one surface of the porous layer 433. The gas diffusion layer 434 is formed in a sheet shape from a conductive material having air permeability or liquid permeability. The gas diffusion layer 434 is bonded to the other surface of the conductive porous layer 433 and sandwiches the porous layer 433 with the cathode catalyst layer 432.

  The cathode catalyst layer 432 contains a catalyst (cathode catalyst) having an ability to reduce oxygen. The cathode catalyst layer 432 is preferably a porous layer formed of a cathode catalyst and a proton conductive binder. The cathode catalyst preferably has a form in which at least one of noble metal particles and noble metal alloy particles is supported on a conductive carrier.

  The noble metal particles are preferably composed of at least a noble metal selected from the group consisting of platinum Pt, ruthenium Ru, rhodium Rh, palladium Pd, and iridium Ir. However, this is not restrictive.

  When noble metal alloy particles are used as the cathode catalyst, it is possible to improve the dissolution resistance and activity of the cathode catalyst. Examples of such noble metal alloy particles include, but are not particularly limited to, the following description, alloys including only two or more kinds of noble metal elements, alloys including noble metal elements and other metal elements, and the like.

  The noble metal alloy particles can obtain a high catalytic activity effect. For this reason, noble metal alloy particles based on platinum Pt may be used. Specifically, an alloy of one or more noble metal elements and platinum Pt is preferable. The one or more noble metal elements include noble metals other than platinum Pt such as ruthenium Ru, rhodium Rh, palladium Pd, iridium Ir, and the like, for example, titanium Ti, vanadium V, chromium Cr, manganese Mn, iron Fe, cobalt Co, and nickel Ni. Selected from the group.

  Although the alloy composition of the noble metal alloy particles depends on the type of metal element to be alloyed, platinum (Pt) is 30 atomic% to 95 atomic%, and the metal element to be alloyed is 5 atomic% to 70 atomic%. Is preferred. Here, “alloy” is a general term for a plurality of metal elements, or those having metallic properties formed from metal elements and non-metal elements. Alloys include solid solutions that are completely dissolved, eutectics in which the component metal elements are independent at the crystal level, and intermetallic compounds that are bonded at a certain ratio at the atomic level. An alloy in the state of

  The conductive support of the cathode catalyst layer 432 supports noble metal particles and / or noble metal alloy particles (that is, at least one of these particles). This conductive carrier is selected in consideration of electron conductivity, gas diffusibility, adhesion to the cathode catalyst, and the like. For example, carbon black, activated carbon, graphite and the like can be used, and a nanocarbon material can also be used. Examples of carbon black include furnace black, channel black, acetylene black, Vulcan (registered trademark; Cabot Corporation), and ketjen black. The nanocarbon material may be any of a fiber shape, a tube shape, a coil shape, and a sheet shape, for example.

The specific surface area of the conductive support, the cathode catalyst may be a sufficient to highly dispersed carrier, specifically ^a 50m ² / g~1400m 2 / g. If the specific surface area is less than 50 m ² / g, the dispersibility of the cathode catalyst in the conductive support may be reduced, and sufficient catalytic action may not be obtained. On the other hand, if the specific surface area exceeds 1400 m ² / g, the effective utilization rate of the cathode catalyst may decrease, and sufficient catalyst performance may not be obtained. Therefore, the specific surface area of the conductive support may be in the range, preferred specific surface area of ^{80m 2} / ^g~1200m 2 / g, more preferably a specific surface area of 100m ² / g~1000m ² / g.

  When the noble metal particles or the noble metal alloy particles are used as the cathode catalyst in the cathode catalyst layer 432 in which the cathode catalyst is supported on the conductive support, the noble metal particles or the noble metal alloy particles are supported on the same conductive material forming the conductive support. Alternatively, it may be supported on a different conductive material forming a conductive carrier. Similarly, when both the noble metal particles and the noble metal alloy particles are used as the cathode catalyst in the cathode catalyst layer 432 in which the cathode catalyst is supported on the conductive carrier, the noble metal particles and the noble metal alloy particles have the same conductivity as the conductive carrier. It may be carried on a material or may be carried on a different conductive material forming a conductive carrier.

  In the cathode catalyst layer 432 formed by supporting at least one of noble metal particles or noble metal alloy particles as a cathode catalyst on a conductive support, the amount of the cathode catalyst supported is 10 wt% with respect to the total mass of the cathode catalyst layer 432. % To 90 wt% is preferable.

  When the loading amount of the cathode catalyst is less than 10 wt%, the catalyst activity per unit mass is lowered and the desired catalyst performance is lowered. This is not preferable because a large amount of the cathode catalyst is required to obtain the desired catalyst performance. Moreover, it is not preferable in that the diffusibility of the reaction characteristics in the cathode catalyst layer 432 is lowered.

  On the contrary, when the loading amount of the cathode catalyst exceeds 90 wt%, the degree of dispersion of the cathode catalyst on the conductive support is lowered. As a result, the catalyst performance is not sufficiently improved for an increase in the amount of the cathode catalyst supported, which is not preferable because the cost of the cathode catalyst layer 432 increases.

  Therefore, the supported amount of the cathode catalyst may be in the above range, the preferable supported amount is 20 wt% to 80 wt%, and the more preferable supported amount is 30 wt% to 70 wt%.

  When the catalyst particles of the cathode catalyst are nanoparticles, the highest activity can be obtained. The average particle size of the catalyst particles is desirably 10 nm or less. If the average particle diameter of the catalyst particles exceeds 10 nm, the activity efficiency of the catalyst may be significantly reduced. A more preferable range of the average particle diameter of the catalyst particles is 0.5 nm to 10 nm. When the average particle diameter of the catalyst particles is less than 0.5 nm, it is difficult to control the catalyst synthesis process, and the catalyst production cost increases. As the catalyst particles, fine particles having an average particle diameter of 10 nm or less may be used alone, but aggregates (secondary particles) of primary particles made of the fine particles may be used.

  The cathode catalyst can be produced using a solution method such as an impregnation method, a precipitation method, a colloid method, or a dry method such as a sputtering method. Specific examples of the method for producing the cathode catalyst are as follows.

  First, acetylene black is dispersed in an aqueous solution in which chloroplatinic acid is dissolved, and sodium bicarbonate is added dropwise thereto to adjust the pH of the solution to 7-8. As a result, Pt oxide was supported on acetylene black. Next, the solid content was separated from the solution by filtration, washed with an aqueous sulfuric acid solution, and then dried at 60 ° C. (in the atmosphere). Thereafter, the obtained solid was pulverized and reduced with hydrogen gas to carry Pt on acetylene black. The amount of Pt supported was 10 wt%.

  The crystal structure of the cathode catalyst can be confirmed by assigning a diffraction peak in X-ray diffraction analysis (XRD). For example, RINT1200 manufactured by Rigaku can be used as an X-ray diffraction analysis (XRD) apparatus.

  The sample can be evaluated by a powder sample obtained by cutting out a part of the catalyst layer used for the synthesized catalyst or the cathode of the oxygen reduction cell. When taking out the catalyst from the sample, the cross-sectional portion of the substantially central portion of the surface having the maximum surface area of the product is used as the sample. The analysis sample was pulverized in an agate mortar and used a powder that passed through a 45 μm sieve.

  In the measurement, a glass sample plate (size of sample portion: length 20 mm × width 20 mm × depth 0.2 mm) was filled with a glass plate so that the analysis sample was smooth with the surface of the sample plate.

  The measurement conditions are as follows. For details on other measurement methods, refer to “Guidelines for X-ray diffraction (revised third edition)” issued by Rigaku Denki Co., Ltd.

Tube: Cu
Tube voltage: 40 kV
Tube current: 40 mA
Divergence slit: 1 deg
Scattering slit: 1 deg
Receiving slit: 0.30mm
Sampling angle: 0.020 deg
Scanning speed: 2 deg / min The average particle diameter of the cathode catalyst can be calculated from the crystallite diameter determined from the half width of the strongest diffraction peak of the catalyst in X-ray diffraction analysis (XRD). The Scherrer equation was used for the calculation.

  The composition analysis of the noble metal catalyst contained in the cathode catalyst layer 432 can be evaluated by inductively coupled plasma emission spectroscopy (ICP).

The analysis sample can also be evaluated by a powder sample obtained by cutting out a part of the catalyst layer used for the electrode catalyst or the cathode of the oxygen reduction cell. There are several methods for the pretreatment (solution) of the analysis sample, and these can be used in appropriate combination according to the element used for the catalyst. For example, in the case of an acid dissolution method, concentrated hydrochloric acid that forms a complex with many elements to assist dissolution, nitric acid having strong oxidizing power, hot concentrated sulfuric acid capable of high-temperature heat decomposition, and the like can be used. Further, when it is difficult to dissolve with a single acid, a mixed acid obtained by combining these acids may be used. When acid decomposition is difficult, pretreatment can be performed by an alkali melting method having a strong dissolving power by high-temperature melting. In this dissolution method, sodium carbonate (Na ₂ CO ₃ ), sodium peroxide (Na ₂ O ₂ ), a mixture of sodium hydroxide and sodium nitrate (NaOH + NaNO ₃ ), or the like can be used as the decomposition agent.

  The cathode catalyst layer 432 in the cathode 431 is a porous layer formed of a cathode catalyst and a proton conductive binder. The proton conductive binder is used to immobilize the cathode catalyst, and a perfluorosulfonic acid polymer (for example, product name: Nafion manufactured by DuPont) is selected.

  It is desirable that the cathode catalyst layer 432 has a catalyst layer structure that maintains a high proton conductivity and conductivity while maintaining a porosity that facilitates material diffusion. For this reason, the mixing ratio of the catalyst support and the proton conductive binder is such that the mass ratio (P / C) of the proton conductive binder (P) is 0.05 to 0.5 with respect to the total mass (C) of the catalyst layer. A range is desirable. If the mass ratio P / C is greater than 0.5, the continuity of the catalyst-supporting carbon may be reduced and the conductivity may be lowered.

  The cathode catalyst layer 432 is formed immediately above the conductive porous layer (MPL) 433 joined to the gas diffusion layer (GDL) 434. As the GDL with MPL, a commercially available product can be appropriately selected and used.

  The gas diffusion layer 434 is a sheet made of a material having air permeability or liquid permeability, such as carbon paper, carbon cloth, carbon felt, or the like, which has been appropriately given water repellency by a water repellent, and has conductivity. The conductive porous layer (MPL) 433 is a porous layer made of a water repellent and carbon particles.

  As the water repellent used for the gas diffusion layer 434 and the conductive porous layer 433, a fluororesin is selected. For example, polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer resin (FEP), tetrafluoroethylene perfluoroalkyl vinyl ether copolymer resin (PFA), and the like can be used.

  As the carbon particles used for the conductive porous layer 433, the same carbon particles as those described above can be used.

  The cathode catalyst layer 432 can be produced by the following method, for example. First, a cathode catalyst and a proton conductive binder are mixed and dispersed in an organic solvent such as water or alcohol to form a catalyst slurry. Next, this slurry is applied to the gas diffusion layer 434 and dried. Thereby, the cathode catalyst layer 432 is formed. The dispersion method is not particularly limited, and examples thereof include a dissolver, a ball mill, and a homogenizer.

As a specific manufacturing method of the cathode 431, for example, 5 g of water, 8 g of 1-propanol, 8 g of 2-propanol, and 2 g of ethylene glycol were weighed and mixed with 1 g of Pt / C obtained above, and zirconia balls were used. Mix for 1 hour on a ball mill. The obtained catalyst slurry was applied to the MPL surface of GDL with MPL, dried at 60 ° C. in the air, and then washed with 1% hydrogen peroxide solution for 1 hour to prepare cathode 431. The catalyst amount of Pt determined from the composition of the catalyst slurry and the weight change of the GDL with MPL was 1 mg / cm ² .

  The polymer electrolyte membrane 435 will be described. The electrolyte membrane 435 is preferably a thin film made of a perfluorocarbon sulfonic acid polymer because of its high proton conductivity. As the electrolyte membrane 435, for example, fluorine resin having a sulfonic acid group such as Nafion (registered trademark: manufactured by DuPont), Flemion (registered trademark: manufactured by Asahi Kasei Co., Ltd.), Aciplex (registered trademark: manufactured by Asahi Glass Co., Ltd.), etc. Can be mentioned. However, the electrolyte membrane 435 is not limited to these, and the electrolyte membrane 435 may be a thin film made of an organic polymer material having a sulfonic acid group. The film thickness of the polymer electrolyte membrane 435 is preferably 10 μm to 150 μm in consideration of membrane resistance. A more preferable film thickness is 30 μm to 100 μm.

  The vaporization layer 438 of the electrode assembly 436 will be described. The vaporization layer 438 is an anode water adjustment unit that suppresses the amount of water transferred to the anode, and is formed of a porous material. The water (liquid) supplied from the anode chamber 442 is converted into water vapor, and the water vapor is converted into water vapor. Provided to supply to the anode 430. Therefore, the vaporization layer 438 is a gas-liquid separation layer. The vaporized layer 438 is formed of a material having excellent thermal conductivity, in other words, a material having high thermal responsiveness, for example, a carbon porous body such as carbon paper, carbon cloth, or carbon felt.

  The vaporization layer 438 contains a water repellent that imparts a water repellent function. The water repellent function of the vaporization layer 438 prevents water (liquid) supplied to the anode chamber 442 from coming into direct contact with the anode 430. The water repellent includes fluororesins such as polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoroethylene copolymer resin (FEP), and tetrafluoroethylene perfluoroalkyl-vinyl ether copolymer resin (PFA). Can be preferably used.

  There is no guarantee that the treatment of the water repellent (fluororesin) on the carbon porous body will be performed uniformly. For this reason, when the content of the fluororesin is less than 5 wt (mass)%, the water-repellent function in the vaporization layer 438 becomes insufficient, and water (liquid) in the anode chamber 442 passes through the vaporization layer 438 to the anode 430. There is a risk of reaching. When the content of the fluororesin exceeds 50 wt (mass)%, the water repellent (fluororesin) is filled in the pores of the carbonaceous porous body, and the pore volume is reduced. As a result, the amount of water vapor supplied from the vaporized layer 438 to the anode 430 decreases, and it becomes difficult to obtain a sufficient current density necessary for the oxygen reduction operation, so that the rate of oxygen reduction may be slow.

  Therefore, the content of the water repellent (fluororesin) in the carbon porous body is preferably 5 wt% to 50 wt%, more preferably 8 wt% to 40 wt%, and 10 wt% to 35 wt%. Is more preferable.

  The vaporized layer 438 has the pore diameter, porosity, and layer thickness of the vaporized layer 438 set as follows in order to supply water (water vapor) necessary for the operation of the oxygen reduction cell 423 to the anode 430 without excess or deficiency. Has been.

  In the pore distribution with the pore diameter of the vaporized layer 438 as the horizontal axis and the pore volume of the vaporized layer 438 as the vertical axis, when the median diameter of the pore is less than 15 μm, the vaporized layer 438 to the anode 430 The supply amount of water vapor is less than the appropriate amount, and it becomes difficult to obtain a sufficient current density necessary for the oxygen reduction operation, which may reduce the rate of oxygen reduction. Further, since the treatment with the water repellent agent is not necessarily performed uniformly on the carbon porous body, it is conceivable that the median diameter of the pores exceeds 60 μm when the treatment is insufficient. In this case, water (liquid) in the anode chamber 442 may reach the anode 430 through the vaporization layer 438 without becoming water vapor.

  Therefore, the median diameter of the pore diameter is preferably 15 μm to 60 μm, more preferably 20 μm to 55 μm, and even more preferably 25 μm to 50 μm.

  When the porosity of the vaporized layer 438 is less than 40%, the amount of water vapor supplied from the vaporized layer 438 to the anode 430 is less than an appropriate amount, and it is difficult to obtain a sufficient current density necessary for the oxygen reduction operation. Therefore, the rate of oxygen reduction may be slow. On the other hand, if the porosity exceeds 90%, the strength of the vaporized layer 438 is insufficient, and there is a risk of trouble in process management such as water repellent treatment.

  Therefore, the porosity is preferably 40% to 90%, further preferably 45% to 85%, and more preferably 50% to 80%.

  If the vaporized layer 438 has a carbon porous body thickness of less than 100 μm, the vaporized layer 438 is insufficient in strength, and there is a risk that trouble may occur in process management such as water repellent treatment. Also, if the thickness of the porous body exceeds 500 μm, the amount of water vapor supplied from the vaporization layer 438 to the anode 430 is less than the appropriate amount, and it becomes difficult to obtain a sufficient current density necessary for the oxygen reduction operation. The rate of oxygen reduction may be slow. Therefore, the thickness of the vaporization layer 438 is preferably 100 μm to 500 μm, more preferably 110 μm to 450 μm, and even more preferably 130 μm to 400 μm. Note that the thickness of the vaporized layer 438 is obtained by dividing the area of the vaporized layer 438 into 16 regions and measuring the thickness of the center position of each region to obtain an average value of the measured values.

  In addition, the pore diameter and porosity of the vaporization layer 438 in the embodiment can be evaluated using a mercury porosimeter. A mercury porosimeter is an apparatus for evaluating the size of pores in a porous material by a mercury injection method. For this evaluation apparatus, “Autopore 9520 type” manufactured by Shimadzu Corporation can be used.

  The sample of the vaporized layer measured with a mercury porosimeter was dried under reduced pressure at room temperature for several hours, then cut into strips of about 1.2 × 2.5 cm, and 0.07 g to 0.13 g was used as a standard cell. take. Using this sample, the pore diameter and the porosity are measured under each condition of an initial pressure of about 5 kPa (about 0.7 psia, corresponding to a pore diameter of about 250 μm). At this time, the mercury parameters are set to a mercury contact angle of 130 degrees and a mercury surface tension of 485 dynes / cm. The pore volume is measured by detecting the pressure in the measurement process and the amount of mercury injected with a capacitance detector. Then, by modeling the pores into a cylindrical shape, the maximum diameter, bulk density, apparent density, porosity, and pore distribution can be obtained. The relationship between the pressure and the pore diameter through which mercury can enter at that pressure is expressed by the Washburn equation.

  An example of a specific method for manufacturing the vaporization layer 438 used in this embodiment will be described. First, carbon paper is immersed for 1 minute in a PTFE (polytetrafluoroethylene) -dispersed aqueous solution adjusted to a predetermined concentration and dried overnight at room temperature. Next, the carbon paper thus dried is fired at 380 ° C. for 10 minutes in an argon atmosphere. As a result, a vaporized layer 438 made of carbon paper subjected to water repellent treatment is created. In addition, the manufacturing method of this vaporization layer 438 is not specifically limited.

  The content of the water repellent (fluororesin) in the produced vaporized layer 438 can be evaluated by measuring a decrease in weight due to combustion. Alternatively, the fluororesin content of the vaporized layer 438 can also be evaluated by measuring weight loss due to combustion of carbon or fluororesin by differential thermal-thermogravimetric simultaneous measurement (TG-DTA).

  By selecting a structure in which a porous carbon particle layer (MPL) having air permeability or liquid permeability is laminated on the vaporization layer 438, the air permeability and liquid permeability to the anode 430 can be made uniform. . By making the air permeability and liquid permeability to the anode 430 uniform, the oxidation reaction of water on the anode catalyst proceeds smoothly, and an increase in electrolysis voltage can be suppressed. Therefore, it is desirable that the porous carbon particle layer is disposed on the anode 430 side.

  On the other hand, even if the porous carbon particle layer is disposed on the back side of the anode 430, liquid water can be uniformly diffused into the vaporization layer 438 through the porous carbon particle layer. Thereby, the air permeability and liquid permeability to the anode 430 are further promoted. Therefore, although it is possible to dispose a porous carbon particle layer on both sides of the vaporization layer 438, the disposition of the porous carbon particle layer is appropriately determined in consideration of the required cost, the performance of the oxygen reduction cell 423, and the lifetime. Just choose.

  The porous carbon particle layer is a porous layer composed of a water repellent and carbon particles. A fluororesin is selected as the water repellent material. For example, polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer resin (FEP), tetrafluoroethylene perfluoroalkyl vinyl ether copolymer resin (PFA) ) Etc. can be used. As the carbon particles, the same conductive particles as those described above can be used.

  Since the porous carbon particle layer has a water-repellent function necessary for making air permeability and liquid permeability uniform, it appropriately contains a fluororesin. If the content of the fluororesin is less than 5 wt%, the water repellent function is insufficient, and liquid water may stagnate inside the porous carbon particle layer and block the pores. When the content of the fluororesin exceeds 50 wt%, the fluororesin fills the pores of the porous carbon particle layer and decreases the pore volume. As a result, the amount of water vapor supplied to the anode 430 is reduced, and the current density necessary for the oxygen reduction operation cannot be sufficiently obtained, so that the oxygen reduction rate may be delayed. Therefore, the fluororesin content is desirably 5 wt% to 50 wt%, preferably 8 wt% to 40 wt%, and more preferably 10 wt% to 35 wt%.

  The porous carbon particle layer has an appropriate thickness for uniform air permeability and liquid permeability. If the thickness of the porous carbon particle layer is less than 10 μm, it is difficult to obtain a uniform porous carbon particle layer due to the unevenness of the vaporized layer 438 as a base material, and the air permeability and liquid permeability are made uniform. Becomes difficult. On the other hand, if the thickness of the porous carbon particle layer is larger than 100 μm, the supply amount of water vapor to the anode 430 is reduced and the current density necessary for the oxygen reduction operation cannot be obtained sufficiently, so that the oxygen reduction rate becomes slow. There is a fear. Accordingly, the thickness of the porous carbon particle layer is desirably 10 μm to 100 μm, preferably 15 μm to 80 μm, and more preferably 20 μm to 50 μm.

  The thickness of the porous carbon particle layer was an average value obtained by observing the cross section of the vaporized layer 438 with a scanning electron microscope and observing at least five locations. The measurement conditions were as follows.

Apparatus: JXA-8100 manufactured by JEOL Ltd.
SEM observation conditions: acceleration voltage: 15 kV, magnification: 400 times As a specific example of a method for producing the vaporized layer 438 on which the porous carbon particle layer used in the embodiment is laminated, a known method can be used.

  For example, first, carbon particles and an aqueous PTFE dispersion are mixed and dispersed in an organic solvent such as water or alcohol to a predetermined concentration and composition to form a slurry. Next, this slurry is applied to a vaporized layer prepared in advance and dried, and this is fired at 380 ° C. for 10 minutes in an argon atmosphere, thereby producing a vaporized layer 438 on which a porous carbon particle layer is laminated. . The dispersion method in this production method is not particularly limited, and a dissolver, a ball mill, a homogenizer, or the like can be used. A coating method in the production method is not particularly limited, and can be performed by a casting method, a spray method, or the like. The vaporized layer 438 on which a commercially available porous carbon particle layer is laminated can be appropriately selected in consideration of required cost, device performance, and lifetime.

  The oxygen reduction unit 422 described above can be manufactured, for example, by the following method.

First, the anode 430, the cathode 431, and the electrolyte membrane 435 of the oxygen-reducing cell 423 are joined (thermocompression bonding) using a device that can be heated and pressurized. Generally, joining is performed by a hot press machine. The press temperature in that case should just be more than the glass transition temperature of the proton conductive polymer from which the binding property of an electrode and the electrolyte membrane 435 is obtained, and is generally 100 to 400 degreeC. The pressing pressure depends on the hardness of the electrode used, but is ^{usually, 5kg / cm 2 ~200kg / cm} 2. Next, the obtained oxygen-reducing cell 423 is combined with a cathode current collector 429 serving as an electrode, a vaporization layer 438 of an electrode assembly 436, and an anode current collector 437 serving as an electrode. Thereby, the oxygen reduction unit 422 can be obtained.

  The oxygen reduction device 421 is disposed in the refrigerator main body 402 so that the oxygen reduction cell 423 can react with oxygen in the oxygen reduction chamber 403. As a specific example, the oxygen reduction device 421 is accommodated in the recess 420 of the refrigerator main body 402 with the air intake port 447 formed in the second case member 445 facing the through hole 402a of the refrigerator main body 402 as shown in FIG. ing. Thus, the cathode chamber 446 and the oxygen reduction chamber 403 are communicated with each other via the through hole 402a, and the cathode 431 of the oxygen reduction cell 423 can react with oxygen in the oxygen reduction chamber 403.

  As shown in FIG. 27, the anode current collector 437 of the oxygen reduction cell 423 is electrically connected to the positive electrode of the power source 424, and the cathode current collector 429 of the oxygen reduction cell 423 is electrically connected to the negative electrode of the power source 424. It is connected. The power source 424 applies a voltage or current between the anode 430 and the cathode 431 of the oxygen reduction cell 423. In addition, the code | symbol 29 in FIG. 27 has shown the detector. The detector 29 detects a voltage or current applied to the oxygen reduction cell 423, and is a voltmeter, for example.

  Each time the door 405 of the refrigerator 401 is opened, the oxygen concentration in the oxygen reduction chamber 403 becomes the same as the oxygen concentration in the atmosphere. For this reason, every time the door 405 is closed, the oxygen reduction device 421 is operated so that the oxygen reduction chamber 403 has a target low oxygen concentration. Next, a reaction (oxygen reduction reaction) in which oxygen in the oxygen reduction chamber 403 is reduced by the operation of the oxygen reduction device 421 will be described.

  In a state where water (liquid) is supplied from the water intake port 443 to the anode chamber 442, a DC voltage is applied between the anode 430 and the cathode 431 of the oxygen reduction cell 423 under the control of the control unit 429, The oxygen reduction cell 423 is operated. Note that the vaporized layer 438 included in the electrode assembly 436 is subjected to water repellent treatment between the anode 430 and the anode chamber 442, so that water (liquid) in the anode chamber 442 directly enters the anode 430 of the oxygen reduction cell 423. There is no contact.

As the oxygen reduction cell 423 is operated, water (H ₂ O) is electrolyzed (oxidized) on the surface of the anode 430, and water (liquid) is generated on the surface of the cathode 431.

That is, oxygen (O ₂ ), protons (H ⁺ ), and electrons (e ⁻ ) are generated by the electrolysis reaction of water at the anode 430. This reaction is represented by the formula (1) shown in the first embodiment. Oxygen (O ₂ ) generated by such water oxidation is discharged out of the anode chamber 442 through the oxygen outlet 444.

On the other hand, the generated proton (H ⁺ ) moves from the anode 430 through the electrolyte membrane 435 to the cathode 431. At the same time, the generated electrons (e ⁻ ) move to the cathode 431 through an external circuit including the power source 424 and the like.

Air (oxygen and nitrogen) in the oxygen reduction chamber 403 is supplied to the cathode chamber 446 through the air intake port 447. Therefore, at the cathode 431, oxygen (O ₂ ) in the oxygen reduction chamber 403 reacts with protons (H +) and electrons (e ⁻ ) supplied to the cathode 431 to generate water (liquid). This reaction is represented by the formula (2) shown in the first embodiment. As described above, oxygen in the air is converted into water by the oxygen reduction reaction at the cathode 431, so that the oxygen concentration in the oxygen reduction chamber 403 decreases. Thereby, it is possible to preserve | save the preservation | save target object accommodated in the oxygen reduction chamber 403 hold | maintained at the temperature lower than the outside of a store | warehouse | chamber, for example, vegetables, maintaining freshness over a long time.

  Since the oxygen reduction reaction described above is an exothermic reaction, the temperature of the oxygen reduction cell 423 and the cell peripheral member joined to the cell so as to conduct heat increase with the oxygen reduction reaction. Although the calorific value of the oxygen reduction cell 423 differs depending on the density of the current passed through the oxygen reduction cell 423 for the oxygen reduction reaction, it was confirmed that the oxygen reduction cell 423 increased by about 30 ° C. due to its operation. Accordingly, the temperature of the vaporization layer 438 having high thermal responsiveness with respect to the oxygen reduction cell 423 rises close to the temperature of the oxygen reduction cell 423.

  For this reason, in the oxygen reduction reaction, water (liquid) supplied from the anode chamber 442 through the anode current collector 437 to the vaporized layer 438 is heated in the vaporized layer 438 and converted into water vapor to the anode 430. Supplied.

  The pressure of water vapor supplied to the anode 430 is defined by the saturated water vapor pressure. This suppresses water molecules from passing through the electrolyte membrane 435 from the anode 430 and moving to the cathode 431 together with protons (H +).

  In this way, excess water is suppressed from being transferred from the anode 430 to the cathode 431 to the cathode 431 that generates water (liquid) by the reaction in the above formula (2). Therefore, excessive stagnation of water (liquid) at the cathode 431 can be suppressed. At the same time, the water (liquid) in the anode chamber 442 is restrained from being transferred from the anode 430 to the cathode 431 as extra water, so that the water required for the reaction at the anode 430 is transferred to the anode 430. There is no risk of supply shortage.

  As the stagnation of water (liquid) at the cathode 431 is suppressed, the cathode flooding phenomenon is less likely to occur. For this reason, it is suppressed that water (liquid) obstruct | occludes the pore of the cathode catalyst layer 432, and the supply of the oxygen in the oxygen reduction chamber 403 to the cathode catalyst layer 432 is prevented. Therefore, the voltage required for the oxygen reduction reaction can be prevented from becoming excessive, and the performance reduction of the oxygen reduction device 421 can be suppressed.

  In the oxygen reduction operation, water (liquid) supplied to the anode chamber 442 may contain impurity ions such as metal ions. In this case, as described above, the water in the anode chamber 442 is heated by the vaporization layer 438 before reaching the anode 430 and supplied to the anode 430 as water vapor. Thus, the vaporization layer 438 exhibits ion trap performance by distilling water.

  Thereby, impurity ions such as metal ions are prevented from accumulating in the electrolyte membrane 435, so that the proton (H +) conductivity in the electrolyte membrane 435 is suppressed from decreasing. As a result, the electrical resistance of the oxygen reduction cell 423 is increased, and an excessive increase in the voltage required for the oxygen reduction reaction is suppressed, so that a decrease in the performance of the oxygen reduction device can be suppressed.

  Further, in the operation of the oxygen reduction device 421, movement of excess water molecules from the anode 430 to the cathode 431 can be suppressed by supplying water vapor to the anode 430 through the vaporization layer 438 as described above. This suppresses the electrolyte membrane 435 from being swollen with water molecules during the oxygen reduction operation. On the other hand, the electrolyte membrane 435 is heated by the residual heat of the oxygen reduction cell 423 as the oxygen reduction device 421 is stopped. Nevertheless, changes in the dimensions of the electrolyte membrane 435 due to swelling and drying of the electrolyte membrane 435 are suppressed. Therefore, it is possible to suppress delamination at the joint surface between the electrolyte membrane 435 and the anode 430 of the oxygen reduction cell 423, and to suppress a decrease in durability of the oxygen reduction device 421.

  In the oxygen reduction device 421, the amount of water vapor supplied to the anode 430 is affected by the vaporization layer 438. For this reason, an electric heater may be attached to the outside of the oxygen reduction unit 422, specifically, the case 425, and the temperature of the oxygen reduction unit 422 having the oxygen reduction cell 423 may be controlled by the heat generated by the heater. As a result, the amount of water vapor supplied to the anode 430 can be stably controlled.

  Hereinafter, examples of the oxygen reduction device 421 will be described.

Example 1
In Example 1, the vaporized layer 438 is obtained by the following manufacturing method. First, carbon paper having a thickness of 180 μm is immersed in an aqueous PTFE dispersion for 1 minute, and then dried overnight at room temperature. Next, the carbon paper thus dried is baked at 380 ° C. for 10 minutes in an argon atmosphere. To do. As a result, a vaporized layer 438 made of carbon paper having a PTFE content of 5 wt% as a fluororesin was obtained. As a result of evaluating the vaporized layer 438 by pore distribution measurement, the median diameter of the vaporized layer 438 was 35 μm, and the porosity was 70%.

The oxygen reduction unit 422 in Example 1 was obtained by the following manufacturing method. An anode 430 made by the above-described manufacturing method and having a size of 20 cm ² is prepared. A cathode 431 made of the above-described manufacturing method and having a size of 12 cm ² is prepared. Along with this, an electrolyte membrane (registered trademark; Nafion, manufactured by DuPont) 35 having a thickness of 50 μm and a size of 30 cm ² is prepared. The anode 430, the cathode 431, and the electrolyte membrane 435 were joined by heating and pressurizing with a hot press machine (thermocompression bonding) to obtain an oxygen-reducing cell 423. Hot pressing was performed under the conditions of a temperature of 160 ° C., a pressure of 20 kg / cm ² , and a pressing time of 3 minutes. Then, the oxygen reduction unit 422 is obtained by preparing and combining the elements of the oxygen reduction cell 423 and other elements, that is, the vaporization layer 438, the anode current collector 437, and the cathode current collector 429.

  Evaluation in Example 1 is as follows.

  The oxygen reduction unit 422 was sandwiched between the first case member 441 and the second case member 445, and these were connected to create a case 425. Thereby, the oxygen reduction device 421 is created. The anode current collector 437 and the cathode current collector 429 of this apparatus were connected to a power source 424. In the evaluation of the oxygen reduction device 421, the anode chamber 442 of the first case member 441 in which the anode 430 is housed is filled with water (liquid), and the cathode chamber 446 in the second case member 445 in which the cathode 431 is housed is filled. Air was supplied by spontaneous breathing.

In such a state, a voltage was applied to the oxygen reduction cell 423 by the power source 424, and the reaction current was controlled to be a constant current. In this constant current control, for example, a voltage applied to the oxygen reduction cell 423 is detected by a voltmeter 427 (see FIG. 27) as voltage detection means, and the control unit 429 outputs the output voltage of the power source 424 based on the detection information. It was done by controlling. By this constant current control, for example, a constant current of 0.2 A / cm ² was applied to the oxygen reduction cell 423 to perform the oxygen reduction reaction, and the electrolysis voltage was measured 1 hour and 1000 hours after the start of the reaction. The results are shown in the table of FIG.

(Example 2)
In the same manner as in Example 1, a vaporized layer 438 made of carbon paper having a thickness of 180 μm and a PTFE content of 10 wt% was produced. As a result of evaluating the vaporized layer 438 by pore distribution measurement, the median diameter of the vaporized layer 438 was 35 μm, and the porosity was 65%. An oxygen reduction device having this vaporized layer 438 was prepared by performing the same operation as in Example 1, and the oxygen reduction reaction was performed by the same operation as in Example 1. After 1 hour and 1000 hours from the start of the reaction, The electrolysis voltage of was measured. The results are shown in the table of FIG. 28 to the table of FIG.

(Example 3)
In the same manner as in Example 1, a vaporized layer 438 made of carbon paper having a thickness of 180 μm and a PTFE content of 30 wt% was produced. As a result of evaluating the vaporized layer 438 by pore distribution measurement, the median diameter of the vaporized layer 438 was 35 μm, and the porosity was 60%. An oxygen reduction device having this vaporized layer 438 was prepared by performing the same operation as in Example 1, and the oxygen reduction reaction was performed by the same operation as in Example 1. After 1 hour and 1000 hours from the start of the reaction, The electrolysis voltage of was measured. The results are shown in the table of FIG.

Example 4
In the same manner as in Example 1, a vaporized layer 438 made of carbon paper having a thickness of 180 μm and a PTFE content of 50 wt% was produced. As a result of evaluating the vaporized layer 438 by pore distribution measurement, the median diameter of the vaporized layer 438 was 35 μm, and the porosity was 55%. An oxygen reduction device having this vaporized layer 438 was prepared by performing the same operation as in Example 1, and the oxygen reduction reaction was performed by the same operation as in Example 1. After 1 hour and 1000 hours from the start of the reaction, The electrolysis voltage of was measured. The results are shown in the table of FIG.

(Example 5)
In the same manner as in Example 1, a vaporized layer 438 made of carbon paper having a thickness of 180 μm and a PTFE content of 1 wt% was produced. As a result of evaluating the vaporized layer 438 by pore distribution measurement, the median diameter of the vaporized layer 438 was 35 μm, and the porosity was 75%. An oxygen reduction device having this vaporized layer 438 was prepared by performing the same operation as in Example 1, and the oxygen reduction reaction was performed by the same operation as in Example 1. After 1 hour and 1000 hours from the start of the reaction, The electrolysis voltage of was measured. The results are shown in the table of FIG.

(Example 6)
In the same manner as in Example 1, a vaporized layer 438 made of carbon paper having a thickness of 180 μm and a PTFE content of 60 wt% was produced. As a result of evaluating the vaporized layer 438 by pore distribution measurement, the median diameter of the vaporized layer 438 was 35 μm and the porosity was 45%. An oxygen reduction device having this vaporized layer 438 was prepared by performing the same operation as in Example 1, and the oxygen reduction reaction was performed by the same operation as in Example 1. After 1 hour and 1000 hours from the start of the reaction, The electrolysis voltage of was measured. The results are shown in the table of FIG.

(Comparative Example 1)
An oxygen reduction device without a vaporization layer was created. Therefore, in the oxygen reduction device of Comparative Example 1, the anode current collector is directly joined to the anode. Using the oxygen reduction apparatus of Comparative Example 1, the oxygen reduction reaction was performed in the same manner as in Example 1, and the electrolysis voltage was measured 1 hour and 1000 hours after the start of the reaction. The results are shown in the table of FIG.

  As shown in the table of FIG. 28, the oxygen reduction devices of Examples 1 to 4 including the vaporized layer having a fluororesin content of 5 wt% or more and less than 50 wt% include the vaporized layer having a fluororesin content of 1 wt%. 1000 hours compared with the oxygen reduction device of Example 5 provided, the oxygen reduction device of Example 6 provided with a vaporization layer having a fluororesin content of 60 wt%, and the oxygen reduction device of Comparative Example 1 provided with no vaporization layer It was confirmed that the subsequent electrolysis voltage could be kept low. That is, when the fluorine content of the vaporized layer 438 is in the range of 5 wt% to 50 wt%, the amount of water vapor supplied from the vaporized layer 438 to the anode 430 is appropriate.

  This limits the amount of water that permeates the cathode 431 even when electrolysis is performed for a long time, so that the water generated by the electrolysis is smoothly discharged from the cathode 431 and maintains a low electrolysis voltage even after 1000 hours. it can. From this, it is understood that the fluorine content of the vaporization layer 438 that can supply the amount of water vapor necessary for the operation of the oxygen reduction cell 423 to the anode 430 without excess or deficiency is preferably 5 wt% to 50 wt%. It has become clear that the oxygen reduction device that has been removed and the oxygen reduction device without the vaporization layer are not suitable for long-time operation.

(Example 7)
In the same manner as in Example 1, a vaporized layer 438 made of carbon paper having a thickness of 180 μm and a PTFE content of 10 wt% was produced. As a result of evaluating the vaporized layer 438 by pore distribution measurement, the median diameter of the vaporized layer 438 was 60 μm, and the porosity was 65%. An oxygen reduction device having this vaporized layer 438 was prepared by performing the same operation as in Example 1, and the oxygen reduction reaction was performed by the same operation as in Example 1. After 1 hour and 1000 hours from the start of the reaction, The electrolysis voltage of was measured. The results are shown in the table of FIG.

(Example 8)
In the same manner as in Example 1, a vaporized layer 438 made of carbon paper having a thickness of 180 μm and a PTFE content of 10 wt% was produced. As a result of evaluating the vaporized layer 438 by pore distribution measurement, the median diameter of the vaporized layer 438 was 45 μm and the porosity was 65%. An oxygen reduction device having this vaporized layer 438 was prepared by performing the same operation as in Example 1, and the oxygen reduction reaction was performed by the same operation as in Example 1. After 1 hour and 1000 hours from the start of the reaction, The electrolysis voltage of was measured. The results are shown in the table of FIG.

Example 9
In the same manner as in Example 1, a vaporized layer 438 made of carbon paper having a thickness of 180 μm and a PTFE content of 10 wt% was produced. As a result of evaluating the vaporized layer 438 by pore distribution measurement, the median diameter of the vaporized layer 438 was 15 μm, and the porosity was 65%. An oxygen reduction device having this vaporized layer 438 was prepared by performing the same operation as in Example 1, and the oxygen reduction reaction was performed by the same operation as in Example 1. After 1 hour and 1000 hours from the start of the reaction, The electrolysis voltage of was measured. The results are shown in the table of FIG.

(Example 10)
In the same manner as in Example 1, a vaporized layer 438 made of carbon paper having a thickness of 180 μm and a PTFE content of 10 wt% was produced. As a result of evaluating the vaporized layer 438 by pore distribution measurement, the median diameter of the vaporized layer 438 was 100 μm, and the porosity was 65%. An oxygen reduction device having this vaporized layer 438 was prepared by performing the same operation as in Example 1, and the oxygen reduction reaction was performed by the same operation as in Example 1. After 1 hour and 1000 hours from the start of the reaction, The electrolysis voltage of was measured. The results are shown in the table of FIG.

(Example 11)
In the same manner as in Example 1, a vaporized layer 438 made of carbon paper having a thickness of 180 μm and a PTFE content of 10 wt% was produced. As a result of evaluating the vaporized layer 438 by pore distribution measurement, the median diameter of the vaporized layer 438 was 10 μm, and the porosity was 65%. An oxygen reduction device having this vaporized layer 438 was prepared by performing the same operation as in Example 1, and the oxygen reduction reaction was performed by the same operation as in Example 1. After 1 hour and 1000 hours from the start of the reaction, The electrolysis voltage of was measured. The results are shown in the table of FIG.

  As shown in the table of FIG. 29, the oxygen reduction device of Example 2 provided with the vaporization layer whose median diameter of the pores is 15 μm or more and 60 μm, and the oxygen reduction device provided with the vaporization layer of Examples 7 to 9 are Compared with the oxygen reduction apparatus of Example 10 provided with the vaporization layer whose median diameter is 100 micrometers, and the oxygen reduction apparatus of Example 10 provided with the vaporization layer whose median diameter is 10 micrometers, the electrolysis voltage after 1000 hours is obtained. It was confirmed that it could be kept low. That is, when the median diameter of the vaporized layer 438 is in the range of 15 μm to 60 μm, the amount of water vapor supplied from the vaporized layer 438 to the anode 430 is appropriate.

  This limits the amount of water that permeates the cathode 431 even when electrolysis is performed for a long time, so that the water generated by the electrolysis is smoothly discharged from the cathode 431 and maintains a low electrolysis voltage even after 1000 hours. it can. From this, it is understood that the pore diameter of the vaporization layer 438 that can supply the amount of water vapor necessary for the operation of the oxygen reduction cell 423 to the anode 430 without excess or deficiency is such that the median diameter is 15 μm to 60 μm. It became clear that an oxygen reduction device outside this range and an oxygen reduction device without a vaporized layer are not suitable for long-time operation.

(Example 12)
In the same manner as in Example 1, a vaporized layer 438 made of carbon paper having a thickness of 180 μm and a PTFE content of 10 wt% was produced. As a result of evaluating the vaporized layer 438 by pore distribution measurement, the median diameter of the vaporized layer 438 was 35 μm, and the porosity was 90%. An oxygen reduction device having this vaporized layer 438 was prepared by performing the same operation as in Example 1, and the oxygen reduction reaction was performed by the same operation as in Example 1. After 1 hour and 1000 hours from the start of the reaction, The electrolysis voltage of was measured. The results are shown in the table of FIG.

(Example 13)
In the same manner as in Example 1, a vaporized layer 438 made of carbon paper having a thickness of 180 μm and a PTFE content of 10 wt% was produced. As a result of evaluating the vaporized layer 438 by pore distribution measurement, the median diameter of the vaporized layer 438 was 35 μm, and the porosity was 75%. An oxygen reduction device having this vaporized layer 438 was prepared by performing the same operation as in Example 1, and the oxygen reduction reaction was performed by the same operation as in Example 1. After 1 hour and 1000 hours from the start of the reaction, The electrolysis voltage of was measured. The results are shown in the table of FIG.

(Example 14)
In the same manner as in Example 1, a vaporized layer 438 made of carbon paper having a thickness of 180 μm and a PTFE content of 10 wt% was produced. As a result of evaluating the vaporized layer 438 by pore distribution measurement, the median diameter of the vaporized layer 438 was 35 μm, and the porosity was 40%. An oxygen reduction device having this vaporized layer 438 was prepared by performing the same operation as in Example 1, and the oxygen reduction reaction was performed by the same operation as in Example 1. After 1 hour and 1000 hours from the start of the reaction, The electrolysis voltage of was measured. The results are shown in the table of FIG.

(Example 15)
In the same manner as in Example 1, a vaporized layer 438 made of carbon paper having a thickness of 180 μm and a PTFE content of 10 wt% was produced. As a result of evaluating the vaporized layer 438 by pore distribution measurement, the median diameter of the vaporized layer 438 was 35 μm, and the porosity was 30%. An oxygen reduction device having this vaporized layer 438 was prepared by performing the same operation as in Example 1, and the oxygen reduction reaction was performed by the same operation as in Example 1. After 1 hour and 1000 hours from the start of the reaction, The electrolysis voltage of was measured. The results are shown in the table of FIG.

  As shown in the table of FIG. 30, the oxygen reduction device of Example 2 and the oxygen reduction devices of Examples 12 to 14 having the vaporization layer 438 having a porosity of 40% or more and less than 90% have a porosity of 30. It was confirmed that the electrolysis voltage after 1000 hours could be kept low as compared with the oxygen reduction device of Example 15 having a vaporization layer of%. That is, when the porosity of the vaporized layer 438 is in the range of 40% to 90%, the amount of water vapor supplied from the vaporized layer 438 to the anode 430 is appropriate.

  This limits the amount of water that permeates the cathode 431 even when electrolysis is performed for a long time, so that the water generated by the electrolysis is smoothly discharged from the cathode 431 and maintains a low electrolysis voltage even after 1000 hours. it can. From this, it is understood that the porosity of the vaporization layer 438 that can supply the amount of water vapor necessary for the operation of the oxygen reduction cell 423 to the anode 430 without excess or deficiency is preferably 40% to 90%. It became clear that the oxygen reduction device and the oxygen reduction device without the vaporization layer are not suitable for long-time operation.

(Example 16)
In the same manner as in Example 1, a vaporized layer 438 made of carbon paper having a thickness of 110 μm and a PTFE content of 10 wt% was produced. As a result of evaluating the vaporized layer 438 by pore distribution measurement, the median diameter of the vaporized layer 438 was 35 μm, and the porosity was 65%. An oxygen reduction device having this vaporized layer 438 was prepared by performing the same operation as in Example 1, and the oxygen reduction reaction was performed by the same operation as in Example 1. After 1 hour and 1000 hours from the start of the reaction, The electrolysis voltage of was measured. The results are shown in the table of FIG.

(Example 17)
In the same manner as in Example 1, a vaporized layer 438 made of carbon paper having a thickness of 270 μm and a PTFE content of 10 wt% was produced. As a result of evaluating the vaporized layer 438 by pore distribution measurement, the median diameter of the vaporized layer 438 was 35 μm, and the porosity was 65%. An oxygen reduction device having this vaporized layer 438 was prepared by performing the same operation as in Example 1, and the oxygen reduction reaction was performed by the same operation as in Example 1. After 1 hour and 1000 hours from the start of the reaction, The electrolysis voltage of was measured. The results are shown in the table of FIG.

(Example 18)
In the same manner as in Example 1, a vaporized layer 438 made of carbon paper having a thickness of 360 μm and a PTFE content of 10 wt% was produced. As a result of evaluating the vaporized layer 438 by pore distribution measurement, the median diameter of the vaporized layer 438 was 35 μm, and the porosity was 65%. An oxygen reduction device having this vaporized layer 438 was prepared by performing the same operation as in Example 1, and the oxygen reduction reaction was performed by the same operation as in Example 1. After 1 hour and 1000 hours from the start of the reaction, The electrolysis voltage of was measured. The results are shown in the table of FIG.

(Example 19)
In the same manner as in Example 1, a vaporized layer 438 made of carbon paper having a thickness of 600 μm and a PTFE content of 10 wt% was produced. As a result of evaluating the vaporized layer 438 by pore distribution measurement, the median diameter of the vaporized layer 438 was 35 μm, and the porosity was 65%. An oxygen reduction device having this vaporized layer 438 was prepared by performing the same operation as in Example 1, and the oxygen reduction reaction was performed by the same operation as in Example 1. After 1 hour and 1000 hours from the start of the reaction, The electrolysis voltage of was measured. The results are shown in the table of FIG.

  As shown in the table of FIG. 31, the oxygen reduction device of Example 2 and the oxygen reduction devices of Examples 16 to 18 having a vaporization layer 438 having a thickness of 100 μm or more and less than 500 μm have a thickness of 600 μm. It was confirmed that the electrolysis voltage after 1000 hours can be kept low compared with the oxygen reduction device of Example 19 provided with a vaporized layer. That is, when the thickness of the vaporized layer 438 is in the range of 100 μm to 500 μm, the amount of water vapor supplied from the vaporized layer 438 to the anode 430 is appropriate.

  This limits the amount of water that permeates the cathode 431 even when electrolysis is performed for a long time, so that the water generated by the electrolysis is smoothly discharged from the cathode 431 and maintains a low electrolysis voltage even after 1000 hours. it can. From this, it can be seen that the thickness of the vaporization layer 438 that can supply the amount of water vapor necessary for the operation of the oxygen reduction cell 423 to the anode 430 without excess or deficiency is preferably 100 μm to 500 μm. The oxygen device and the oxygen reduction device without the vaporized layer are not suitable for long-time operation.

(Example 20)
The water supplied to the anode 430 was adjusted so as to contain 500 ppm of metal impurity ions such as Na, Ca, Al, Fe, Ni, Cu, and Zn, and this was supplied to the oxygen reduction device similar to that in Example 2 for evaluation. did. The results are shown in the table of FIG.

(Comparative Example 2)
The water containing impurity ions prepared in Example 20 was supplied to the oxygen reduction apparatus similar to Comparative Example 1 and evaluated. The results are shown in the table of FIG.

  As shown in the table of FIG. 32, the oxygen reduction apparatus of Example 2 did not change the capacity of the oxygen reduction apparatus even when water (liquid) containing impurity ions was supplied as shown in Example 20. On the other hand, as shown in Comparative Example 2, when water containing impurity ions is supplied to the oxygen reduction device of Comparative Example 1 having no vaporized layer, the electrolytic voltage immediately increases and the performance of the oxygen reduction device decreases. It was confirmed.

  That is, in the oxygen reduction device of Comparative Example 2, if impurity ions such as metal ions are contained in the water supplied to the anode, it accumulates in the polymer electrolyte membrane and the conductivity of hydrogen ions decreases. Resulting in. In contrast, the oxygen reduction device of Example 2 and the oxygen reduction device of Example 20 distill water supplied to the anode 430 by the vaporization layer 438 provided therein, and supply water vapor to the anode 430. For this reason, impurity ions are not accumulated in the electrolyte membrane 435 of the oxygen reduction cell 423. Therefore, the electrolytic voltage after 1000 hours can be maintained in a low state.

(Example 21)
The production of the vaporized layer 438 in which the porous carbon particle layer is laminated will be described. The carbon powder and the PTFE dispersion aqueous solution were mixed with the isopropyl alcohol aqueous solution and stirred to prepare a carbon slurry. In the same manner as in Example 1, a vaporized layer made of carbon paper having a thickness of 180 μm and a PTFE content of 5 wt% was manufactured. The slurry was applied to the vaporized layer by a spray method and dried at 80 ° C. overnight. This was baked at 380 ° C. for 10 minutes in an argon atmosphere to obtain a vaporized layer 438 in which a porous carbon particle layer containing 5% PTFE was laminated to a thickness of 20 μm.

  As a result of evaluating the vaporized layer 438 by pore distribution measurement, the median diameter of the vaporized layer 438 was 35 μm, and the porosity was 70%. An oxygen reduction apparatus having the vaporized layer 438 was produced by performing the same operation as in Example 1. However, the vaporization layer 438 was installed so that the porous carbon particle layer was oriented to the oxygen-reducing cell side. Using this oxygen reduction apparatus, the oxygen reduction reaction was carried out in the same manner as in Example 1, and the electrolytic voltage was measured 1 hour and 1000 hours after the start of the reaction. The results are shown in the table of FIG. 33 and the table of FIG.

(Example 22)
In the same manner as in Example 21, a vaporized layer 438 in which a porous carbon particle layer containing 20% PTFE was laminated to a thickness of 20 μm was manufactured. Using the oxygen reduction device having the vaporized layer 438, the oxygen reduction device was evaluated in the same manner as in Example 21. The results are shown in the table of FIG.

(Example 23)
In the same manner as in Example 21, a vaporized layer 438 in which a porous carbon particle layer containing 50% PTFE was laminated to a thickness of 20 μm was manufactured. Using the oxygen reduction device having the vaporized layer 438, the oxygen reduction device was evaluated in the same manner as in Example 21. The results are shown in the table of FIG.

(Example 24)
In the same manner as in Example 21, a vaporized layer 438 in which a porous carbon particle layer containing 1% PTFE was laminated to a thickness of 20 μm was manufactured. Using the oxygen reduction device having the vaporized layer 438, the oxygen reduction device was evaluated in the same manner as in Example 21. The results are shown in the table of FIG.

(Example 25)
In the same manner as in Example 21, a vaporized layer 438 in which a porous carbon particle layer containing 60% PTFE was laminated to a thickness of 20 μm was produced. Using the oxygen reduction device having the vaporized layer 438, the oxygen reduction device was evaluated in the same manner as in Example 21. The results are shown in the table of FIG.

  As shown in the table of FIG. 33, the oxygen reduction devices of Examples 21 to 23 in which the vaporized layer having a fluororesin content of 5 wt% to 50 wt% contained in the porous carbon particle layer are arranged as porous carbon particles. Oxygen reduction apparatus of Example 24 in which a vaporized layer having a fluorine resin content of 1 wt% is disposed, or an oxygen reduction apparatus in Example 25 in which a vaporized layer having a fluorocarbon resin content of a porous carbon particle layer of 60 wt% is disposed. Compared with the oxygen reduction apparatus of Example 1 (refer to the table of FIG. 28) having no porous carbon particle layer in the apparatus or the vaporized layer, the electrolysis voltage after 1 hour or 1000 hours after the start of the reaction is low. It was confirmed.

  That is, according to the oxygen reduction apparatuses of Examples 21 to 23, the amount of water vapor supplied from the vaporization layer 438 to the anode 430 is appropriate, and the air permeability and liquid permeability to the anode 430 are uniform. Thereby, the oxidation reaction of water on the anode catalyst proceeds smoothly, and an increase in electrolysis voltage is suppressed.

(Example 26)
The production of the vaporized layer in which the porous carbon particle layer is laminated will be described. The carbon powder and the PTFE dispersion aqueous solution were mixed with the isopropyl alcohol aqueous solution and stirred to prepare a carbon slurry. This slurry was applied to the vaporized layer produced in Example 17 by a spray method and dried at 80 ° C. overnight. This was baked at 380 ° C. for 10 minutes in an argon atmosphere to obtain a vaporized layer 438 in which a porous carbon particle layer containing 25% PTFE was laminated to a thickness of 10 μm.

  As a result of evaluating the vaporized layer 438 by pore distribution measurement, the median diameter of the vaporized layer 438 was 35 μm, and the porosity was 65%. An oxygen reduction apparatus having the vaporized layer 438 was produced by performing the same operation as in Example 1. However, the vaporization layer 438 was installed so that the porous carbon particle layer was oriented to the reduced kill cell side. Using this oxygen reduction apparatus, the oxygen reduction reaction was carried out in the same manner as in Example 1, and the electrolytic voltage was measured 1 hour and 1000 hours after the start of the reaction. The results are shown in the table of FIG.

(Example 27)
In the same manner as in Example 26, a vaporized layer 438 in which a porous carbon particle layer containing 25% PTFE was laminated to a thickness of 100 μm was manufactured. Using the oxygen reduction device having the vaporized layer 438, the oxygen reduction device was evaluated in the same manner as in Example 26. The results are shown in the table of FIG.

(Example 28)
In the same manner as in Example 26, a vaporized layer 438 in which a porous carbon particle layer containing 25% PTFE was laminated to a thickness of 80 μm was manufactured. Using the oxygen reduction device having the vaporized layer 438, the oxygen reduction device was evaluated in the same manner as in Example 26. The results are shown in the table of FIG.

(Example 29)
In the same manner as in Example 26, a vaporized layer 438 in which a porous carbon particle layer containing 25% PTFE was laminated to a thickness of 5 μm was manufactured. Using the oxygen reduction device having the vaporized layer 438, the oxygen reduction device was evaluated in the same manner as in Example 26. The results are shown in the table of FIG.

(Example 30)
In the same manner as in Example 26, a vaporized layer 438 in which a porous carbon particle layer containing 25% PTFE was laminated to a thickness of 200 μm was manufactured. Using the oxygen reduction device having the vaporized layer 438, the oxygen reduction device was evaluated in the same manner as in Example 26. The results are shown in the table of FIG.

  As shown in the table of FIG. 34, the oxygen reduction devices of Examples 26 to 28 in which the vaporized layers having a porous carbon particle layer thickness of 10 to 100 μm are arranged have a porous carbon particle layer thickness of 5 μm. The oxygen reduction device of Example 29 in which the vaporization layer was arranged, or the oxygen reduction device of Example 30 in which the vaporization layer having a porous carbon particle layer thickness of 200 μm was arranged, or the vaporization layer had a porous carbon particle layer It was confirmed that the electrolysis voltage after 1 hour or 1000 hours from the start of the reaction was lower than that of the oxygen reduction apparatus of Example 17 (see FIG. 4).

  That is, according to the oxygen reduction devices of Examples 26 to 28, the amount of water vapor supplied from the vaporization layer 438 to the anode 430 is appropriate, and the air permeability and liquid permeability to the anode 430 are uniform. Thereby, the oxidation reaction of water on the anode catalyst proceeds smoothly, and an increase in electrolysis voltage is suppressed.

(Example 31)
A hypoxic device was produced and evaluated in the same manner as in Example 21. However, the vaporized layer 438 was installed so that the porous carbon particle layer was oriented on the surface opposite to the oxygen-reducing cell side. Using the oxygen reduction device having the vaporized layer 438, the oxygen reduction reaction was performed in the same manner as in Example 21 and in the same manner as in Example 1, and the electrolysis voltage after 1 hour and 1000 hours after the start of the reaction. Was measured. The results are shown in the table of FIG.

(Example 32)
The production of the vaporized layer in which the porous carbon particle layer is laminated will be described. The carbon powder and the PTFE dispersion aqueous solution were mixed with the isopropyl alcohol aqueous solution and stirred to prepare a carbon slurry. This carbon slurry was applied to both sides of the vaporized layer produced in Example 1 by a spray method and dried at 80 ° C. overnight. This was baked at 380 ° C. for 10 minutes in an argon atmosphere, and a porous carbon particle layer containing 25% PTFE was formed on both sides of the vaporized layer with a thickness of 25 μm. Using the oxygen reduction device having the vaporized layer 438, the oxygen reduction reaction was performed in the same manner as in Example 1, and the electrolysis voltage was measured 1 hour and 1000 hours after the start of the reaction. The results are shown in the table of FIG.

  As shown in the table of FIG. 35, Example 21 or Example 31 in which the positional relationship between the porous carbon particle layer laminated on the vaporization layer 438 and the anode 430 was changed, or porous carbon particles on both sides of the vaporization layer 438 were obtained. In Example 32 in which the layer was formed, it was confirmed that the electrolysis voltage after 1 hour or 1000 hours from the start of the reaction was lower than in Example 1 in which the vaporized layer 438 did not have a porous carbon particle layer.

  That is, according to the oxygen reduction device of Example 21, or Example 31 or Example 32, the amount of water vapor supplied from the vaporization layer 438 to the anode 430 is appropriate, and the air permeability and liquid flow to the anode 430 are also suitable. Uniformity. Thereby, the oxidation reaction of water on the anode catalyst proceeds smoothly, and an increase in electrolysis voltage is suppressed.

Effects of the embodiment

  In the above-mentioned column “Problems to be solved by the invention”, the problem to be solved of the present invention has been described. The contents of the problem are classified into three and explained in detail based on FIG. 36, and the implementation described above. The effects of Embodiments 1 to 3 will be described. FIG. 36 illustrates an oxygen reduction cell 500. The oxygen reduction cell 500 is formed of an anode 502, a polymer electrolyte membrane 504, and a cathode 506. The cathode 506 includes a cathode catalyst layer 508, MPL (conductivity). A porous layer) 510 and a GDL (gas diffusion layer) 512 are formed. Note that the cathode 506 side is the oxygen reduction chamber.

(1) First problem The first problem is a problem before the hypoxic reaction. As shown in the formulas (1) and (2), the reaction is performed on the anode 502 side and the cathode 506 side, respectively. However, hydrogen ions (protons) H ⁺ and water are transferred from the anode 502 side to the cathode 506 side. 36, liquid entrained water that moves together with protons is generated as shown in FIG. 36, and platinum (Pt) of the catalyst of the cathode catalyst layer 508 is covered with this liquid water and air. Phenomenon (flooding phenomenon) that can not react with oxygen in the inside occurs. That is, it is a problem that the reaction cannot be performed because oxygen does not reach platinum of the catalyst.

(2) Second problem The second problem is a problem after the hypoxic reaction. As shown in FIG. 36, this problem is that, in the cathode 506, protons and oxygen in the air react on platinum of the catalyst, and the platinum of the catalyst is covered with liquid water, so that the following reaction does not occur. It is a problem.

(3) Third problem The third problem is also a problem after the hypoxic reaction. Since the inside of the refrigerator 10 is cooled, water vapor that is a gas is condensed and liquid condensed water is accumulated on the surface of the cathode 506. That is, as shown in FIG. 36, the liquid water flows backward and stays at the cathode 506, and the diffusion resistance is increased when air (oxygen) flows into the cathode 506 by the staying water, and the air flows into the cathode 506. Hard to reach. Moreover, this subject is a peculiar subject for performing a hypoxic reaction inside a refrigerator.

  How the first to third embodiments solve the above three problems to obtain the effect will be described in order.

(4) Solution for First Problem A solution for the first problem will be described. The solution is to reduce the amount of liquid entrained water that moves together with protons by preventing the anode 502 from contacting liquid water with the anode 502 as much as possible. Thereby, the flooding phenomenon which is the first problem can be prevented.

  First, when the anode water adjusting unit moves only water vapor and does not move liquid water, such as a water repellent layer, a space, and a vaporized layer, it is water molecules that adhere to the surface of the anode 502. Therefore, liquid entrained water can be reduced, and only protons can easily pass through the polymer electrolyte membrane 504.

  That is, as described in Embodiment 1, when the anode water adjustment part is a water-repellent layer 126 such as a film, a nonwoven fabric, a porous membrane, or a filter, the surface of the anode 502 becomes water-repellent and hydrophilic, The liquid water that passes through the water repellent layer 126 and reaches the surface of the anode 502 can be reduced, and the liquid entrained water can be reduced.

  As described in the second embodiment, when the anode water adjusting unit is the space A, the liquid water and the surface of the anode 502 are completely out of contact with each other, so that the liquid entrained water is eliminated.

  In the case where the anode water adjusting unit is the vaporization layer 438 as described in the third embodiment, only water vapor passes through the vaporization layer 438 and the amount of liquid water reaching the surface of the anode 502 can be reduced. Has the effect of reducing.

(5) Solution for Second Problem Next, a solution for the second problem will be described.

  After the deoxygenation reaction, the reaction water allows vaporization of the liquid water after oxygen and hydrogen have reacted with platinum in the catalyst, and the platinum in the catalyst is not covered with water, so the next reaction is possible. There is still a possibility that the platinum of the catalyst is covered with liquid water.

  Therefore, as described in the first to third embodiments, since the liquid water is not touching the surface of the anode 502 by the anode water adjustment unit, the liquid water in the cathode 506 is polymerized due to the difference in liquid water concentration. So-called back diffusion occurs in which the electrolyte membrane 504 flows back to the anode 502 and liquid water in the cathode 506 can be reduced, so that the catalyst platinum is not covered with liquid water. Further, the liquid water can be used as water supply on the anode 502 side.

  When the MPL 510 on the cathode 506 side or the GDL 512 with MPL has water repellency, liquid water is unlikely to adhere to the surface, so that there is an effect that water is easily formed and water vapor easily escapes. Since MPL 510 transmits only water vapor, liquid water may remain in the cathode 506, but in order to solve the third problem, it is preferable that water vapor is transmitted. This will be described below.

  As another method for solving the second problem, there is the following method.

  First, air may be blown into the reaction space B described in the second embodiment. This makes it easier for liquid water to move from the cathode 506 to the anode 502 due to the difference in liquid water concentration.

  Moreover, the voltage value of the DC voltage applied to the oxygen reduction unit described in Embodiments 1 to 3 is set higher by a predetermined time than the voltage during oxygen reduction. Thereby, gases other than water are produced | generated by a hypoxic reaction, and the liquid water around platinum of a catalyst can be removed.

  Further, with respect to the DC voltage applied between the anode 502 and the cathode 506, plus and minus are reversed only within a predetermined time. As a result, the liquid water in the cathode 506 undergoes an oxygen reduction reaction, and hydrogen moves to the anode 502 side, so that the water in the cathode 506 disappears. Therefore, the catalyst platinum is not covered with the liquid water.

(6) Solution for Third Problem Next, a solution for the third problem will be described. The solution can be solved by providing the cathode water adjusting portion (water repellent layer 130) as described in the first embodiment. In other words, there is an effect that the cathode water adjusting unit is provided so that condensed water is accumulated on the surface of the cathode 506 and liquid water does not enter the cathode 506, thereby preventing the platinum of the catalyst from being covered with the liquid water. . In addition, when the cathode water adjusting portion has water repellency such as the water repellent layer 130, liquid water does not collect on the surface due to surface tension, so that a gap is formed on the surface, and oxygen is absorbed in the cathode. There is an effect of easily moving to 506.

  Further, as an example of modification of the cathode water adjustment unit, in order to eliminate the dew condensation water, a heating means may be provided in the oxygen reduction unit to warm the surface of the cathode 506 so as to prevent the dew condensation by increasing the saturated water vapor amount.

  As another modification of the cathode water adjusting unit, an air flow path may be formed on the surface of the cathode 506, and fresh air may be sent by air blowing means or natural convection to eliminate condensed water.

Example of change

  In each said embodiment, although the oxygen reduction unit was provided in the refrigerator 10, you may provide in an apparatus other than this and the storage. In other words, it can be applied to commercial and household refrigerators that can preserve vegetables, foods, etc. in a high-quality state for a long time, and can store chemicals, medical materials, chemical substances, etc. that are sensitive to oxygen concentration. Applicable to refrigerators and the like.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 10 ... Refrigerator, 16 ... Vegetable room, 100 ... Hypoxic chamber, 102 ... Oxygen reduction apparatus, 104 ... Container storage part, 106 ... Hypoxic container, 114 ... Case 115 ... Hypoxic unit, 116 ... Electrolyte membrane, 118 ... Anode, 120 ... Cathode, 122 ... Anode current collector, 124 ... Cathode current collector, 126 ... Water repellent layer, 128 ... water supply body, 130 ... water repellent layer, 132 ... fixing member, 134 ... fixing member, 136 ... exhaust port, 138 ... opening, 140 ... Unit storage section 162 ... vent hole, 164 ... vent hole, 211 ... spacer, 213 ... opening, 438 ... vaporization layer

Claims (21)

A polymer electrolyte membrane;
An anode provided on one side of the polymer electrolyte membrane;
A cathode provided on the other side of the polymer electrolyte membrane and leading to a reduced oxygen space;
An anode current collector for energizing the anode;
A cathode current collector for energizing the cathode;
A water supply body provided on the anode side;
An anode water adjusting unit that is provided between the anode and the water supply body and suppresses the amount of water that moves from the water supply body to the anode;
A hypoxic device. The anode water adjusting unit moves only water vapor and does not move liquid water.
The oxygen reduction device according to claim 1. The anode water adjusting part has water repellency;
The oxygen-reducing device according to claim 2. The anode water adjusting part is a space;
The oxygen-reducing device according to claim 2. The space is formed by a water-repellent spacer disposed between the anode and the water supply body.
The oxygen reduction device according to claim 4. The space is formed by an insulating spacer disposed between the anode and the water supply body.
The oxygen reduction device according to claim 4. The spacer has a slit-shaped or lattice-shaped opening,
The oxygen reduction device according to claim 5 or 6. The spacer is formed to have a large thickness only at the portions that contact the anode and the water supply body, respectively.
The oxygen reduction device according to any one of claims 5 to 7. A cathode water adjusting unit that is provided between the cathode and the oxygen reduction space and suppresses the amount of water that moves from the cathode to the oxygen reduction space;
The oxygen reduction device according to any one of claims 1 to 8. The cathode water adjusting unit is a layer that moves only water vapor and does not move water.
The oxygen reduction device according to claim 9. The cathode water adjustment part is a water-repellent polymer film,
The oxygen reduction device according to claim 10. Supplying water to the water supply body through an ion exchange resin;
The oxygen reduction device according to any one of claims 1 to 11. Inside the heat insulating case,
The polymer electrolyte membrane, the anode, the cathode, the anode current collector, the cathode current collector, and the water supply body were housed.
The oxygen-reducing device according to any one of claims 1 to 12. The oxygen reduction device according to claim 2, wherein the anode water adjusting unit is a vaporized layer disposed on at least one of both surfaces of the anode current collector. An electrode assembly is formed by the anode current collector and the vaporized layer,
The electrode assembly is disposed with the anode sandwiched between the electrolyte membrane, and water supplied to the vaporized layer is converted into water vapor in the vaporized layer and supplied to the anode.
The oxygen reduction device according to claim 14. The anode contains a catalyst for oxidizing the supplied water vapor,
The cathode has a cathode catalyst layer containing a catalyst for reducing oxygen;
The polymer electrolyte membrane has proton conductivity,
The oxygen reduction device according to claim 15. A sealed space, and the oxygen reduction device according to any one of claims 1 to 16,
The reduced oxygen space is the sealed space;
Hypoxic chamber. The oxygen-reducing device according to any one of claims 1 to 17, or the oxygen-reducing chamber according to claim 5,
refrigerator. Supplying defrosted water generated from an evaporator provided in the refrigerator to the water supply body,
The refrigerator according to claim 18. The oxygen reduction device is fixed inside the refrigerator cabinet,
The refrigerator according to claim 18. The refrigerator is
A refrigeration room as a first storage room;
A low-temperature chamber that is provided in the refrigeration chamber and has a lower internal temperature than the refrigeration chamber; and
A second storage room set at a higher internal temperature than the cold room;
Have
The oxygen reduction chamber is provided in the second storage chamber;
The refrigerator according to claim 18.

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