Electrolysis module

Abstract

This electrolysis module comprises: a stack outer casing 11; a stack 12 provided inside the stack outer casing 11; and a space S provided between the stack outer casing 11 and the outer periphery of the stack 12 and / or inside the stack 12. A temperature-controlled fluid is supplied into the space S, the fluid being obtained by branching a gas supplied to an air electrode in the stack 12.

Description

Electrolysis Module

[0001] The present invention relates to an electrolysis module.

[0002] Patent Document 1 listed below discloses an electrolysis module (system) including a stack having units in which a plurality of cells, each formed by a vertically stacked anode layer, electrolyte layer, and cathode layer, are stacked, and interconnection plates that connect the units while sandwiching them from above and below. A fuel such as water vapor is supplied to the cathode layer, and air is supplied to the anode layer. From this perspective, the cathode layer is sometimes called the fuel electrode, and the anode layer is sometimes called the air electrode.

[0003] When water vapor is supplied to the anode, electrolysis of the water molecules in the water vapor occurs at the interface between the anode and the electrolyte layer due to the action of the electrolytic current applied to the solid oxide electrolysis cell, producing hydrogen and oxygen ions. The hydrogen is discharged from the outlet of the anode. Meanwhile, the oxygen ions pass through the electrolyte layer and recombine with oxygen at the interface between the electrolyte layer and the air layer. The oxygen is discharged from the outlet of the cathode together with the air supplied to the cathode. That is, when water vapor is supplied to the anode, the water vapor can be converted into hydrogen and oxygen according to the following electrochemical reaction: 2H2O → 2H2 + O2

[0004] Carbon dioxide may also be supplied to the anode. At this time, the carbon dioxide is electrolyzed into carbon monoxide and oxygen ions at the interface between the anode and the electrolyte layer by the action of an electrolytic current applied to the solid oxide electrolysis cell. The carbon monoxide is discharged from the outlet of the anode. The oxygen ions pass through the electrolyte layer and are discharged from the outlet of the cathode as described above. That is, when carbon dioxide is supplied to the anode, it can be converted into carbon monoxide and oxygen according to the following electrochemical reaction: 2CO2 → 2CO + O2

[0005] Water vapor and carbon dioxide may be supplied to the anode to perform co-electrolysis of water vapor and carbon dioxide.

[0006] Japanese Patent Application Laid-Open No. 2023-140335

[0007] The supply gas supplied to the anode and cathode is heated by absorbing Joule heat generated by the electrolysis current applied to the solid oxide electrolysis cell. The pressure of the supply gas is generally 0.2 to 0.9 MPaG. Because the supply gas pressure is high, the temperature change of the stack is strongly affected by the electrolysis current. Conventionally, the electrolysis current is adjusted to adjust the temperature of the entire stack to a temperature appropriate for the targeted electrolysis reaction. While there is an electrolysis current value that is efficient for the targeted electrolysis reaction, temperature control must take priority in order to cause the targeted electrolysis reaction. Therefore, conventionally, the efficiency of the electrolysis reaction is reduced due to stack temperature control.

[0008] The present invention has been made to solve the above-mentioned problems, and one of its objects is to provide an electrolysis module that can improve the efficiency of the electrolysis reaction.

[0009] (1) In one embodiment, the present invention relates to an electrolysis module including a stack exterior body, a stack provided inside the stack exterior body, and a space provided between the stack exterior body and the outer periphery of the stack and / or inside the stack, wherein a temperature-controlled fluid is supplied to the space, and the fluid is a branch of a supply gas supplied to an air electrode of the stack.

[0010] (2) The present invention may relate to the electrolysis module according to (1), wherein the space is divided into a plurality of flow paths.

[0011] (3) The present invention may relate to the electrolysis module according to (1) or (2), wherein the flow path is perpendicular to or opposite to the flow direction of the gas supplied to the anode of the stack.

[0012] (4) The present invention may relate to the electrolysis module according to any one of (1) to (3), wherein co-electrolysis is performed in the stack.

[0013] (5) The present invention may relate to the electrolysis module according to any one of (1) to (4), further comprising: a heat exchanger connected to an inlet and an outlet of the air electrode of the stack for exchanging heat between a supply gas supplied to the air electrode and an exhaust gas exhausted from the air electrode; and a flow path switcher disposed between the outlet of the air electrode and the heat exchanger, configured to switch a flow path between a flow path leading to the heat exchanger and a flow path bypassing the heat exchanger.

[0014] (6) The electrolysis module may relate to any one of (1) to (5), wherein the pressure of the gas supplied to the air electrode and the fuel electrode of the stack is 10 kPaG or more and less than 200 kPaG.

[0015] According to one embodiment of the electrolysis module of the present invention, a temperature-controlled fluid that is a branch of the gas supplied to the air electrode of the stack is supplied to a space provided between the stack exterior body and the outer periphery of the stack and / or inside the stack. This makes it possible to control the temperature of the stack independently of the electrolysis current, thereby improving the efficiency of the electrolysis reaction.

[0016] 1 is an explanatory diagram schematically illustrating an electrolysis module according to a first embodiment of the present invention. It is a cross-sectional view of the solid oxide electrolysis cell of FIG. 1. It is a perspective view showing the stack exterior body and the stack of FIG. 2. It is a longitudinal cross-sectional view of the stack exterior body and the stack taken along plane IV of FIG. 3. It is a cross-sectional view of the stack exterior body taken along line V-V of FIG. 4. It is an explanatory diagram showing fluids flowing in the space of FIG. 4. It is a cross-sectional view of the stack exterior body taken along line VII-VII of FIG. 6. It is an explanatory diagram showing gas supplied to the air electrode of the stack of FIG. 6. It is a cross-sectional view of the stack exterior body taken along line IX-IX of FIG. 8. It is an explanatory diagram showing a first mode of supply of fuel gas to the stack of FIG. 9. It is an explanatory diagram showing a second mode of supply of fuel gas to the stack of FIG. 9. It is a longitudinal cross-sectional view of the stack exterior body and the stack of an electrolysis module according to a second embodiment of the present invention. It is a cross-sectional view of the stack exterior body taken along line XIII-XIII of FIG. 12. It is an explanatory diagram schematically illustrating an electrolysis module according to a third embodiment of the present invention. It is a cross-sectional view of the flow path switch of FIG. 14. It is an explanatory diagram showing the operation of the flow path switch of FIG. 15.

[0017] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to each embodiment, and the components can be modified and embodied without departing from the spirit of the present invention. Furthermore, various inventions can be formed by appropriately combining multiple components disclosed in each embodiment. For example, some components may be omitted from all the components shown in the embodiments. Furthermore, components of different embodiments may be appropriately combined.

[0018] 1 is an explanatory diagram that schematically illustrates an electrolysis module according to a first embodiment of the present invention. The electrolysis module of this embodiment is a module (system) that performs electrolysis of a fuel gas 2 using a solid oxide electrolysis cell 1 (SOEC).

[0019] Various gases may be used as the fuel gas 2. The fuel gas 2 in this embodiment includes steam 3a from the steam supply means 3 and various gases 4a from the various gas supply means 4. The steam supply means 3 in this embodiment includes a water supply source 30 that supplies water (HO), a boiler 31 that heats the water from the water supply source 30 to generate steam 3a, and a pressure regulator 32 and a flow rate regulator 33 connected to the outlet of the boiler 31. The various gas supply means 4 in this embodiment includes various gas supply sources 40 that supply various gases, mass flow meters 41 connected to the various gas supply sources 40 and measuring the mass flow rates of the various gases, and a first heater 42 connected to the outlet of the mass flow meter 41 and heating the various gases as needed. In this embodiment, the various gas supply source 40 supplies carbon dioxide (CO), nitrogen (N), and hydrogen (H). The water vapor 3 a from the water vapor supply means 3 and the various gases 4 a from the various gas supply means 4 are mixed in a mixer 50 such as a static mixer, heated by a second heater 51 as necessary, and then supplied to the solid oxide electrolysis cell 1 as the fuel gas 2.

[0020] As is well known, a solid oxide electrolysis cell 1 has a stack 12 (see FIG. 2 ) that includes units 120 (see FIG. 2 ) in which a plurality of air electrodes (anode layers), a plurality of electrolyte layers, and a plurality of fuel electrodes (cathode layers) are stacked in that order, and interconnection plates 121 (see FIG. 2 ) that connect the units 120 while sandwiching them from above and below. A fuel gas 2 (water vapor 3 a and various gases 4 a) is supplied to the fuel electrodes of the stack 12.

[0021] Due to the action of an electrolytic current applied to the solid oxide electrolysis cell 1 from the power source 6, water vapor 3a supplied to the fuel electrode is electrolyzed at the interface between the fuel electrode and the electrolyte layer, producing hydrogen and oxygen ions. The hydrogen is discharged from the outlet of the fuel electrode. Meanwhile, the oxygen ions pass through the electrolyte layer and recombine with oxygen at the interface between the electrolyte layer and the air layer. The oxygen is discharged from the outlet of the air electrode. That is, in the stack 12 of the solid oxide electrolysis cell 1, water vapor 3a is converted into hydrogen and oxygen according to the following electrochemical reaction: 2H2O → 2H2 + O2

[0022] Furthermore, due to the action of the electrolytic current applied to the solid oxide electrolysis cell 1 from the power source 6, carbon dioxide supplied to the anode is electrolyzed at the interface between the anode and the electrolyte layer to generate carbon monoxide and oxygen ions. Carbon monoxide is discharged from the outlet of the anode. Meanwhile, oxygen ions pass through the electrolyte layer and recombine with oxygen at the interface between the electrolyte layer and the air layer. Oxygen is discharged from the outlet of the air cathode. That is, in the stack 12 of the solid oxide electrolysis cell 1, carbon dioxide is converted to carbon monoxide and oxygen according to the following electrochemical reaction: 2CO2 → 2CO + O2

[0023] In other words, in the stack 12 of the solid oxide electrolysis cell 1 of this embodiment, co-electrolysis of water vapor 3a and carbon dioxide is carried out. The hydrogen and carbon monoxide produced at the fuel electrode are sent to downstream equipment together with the fuel gas 2 (water vapor 3a and various gases 4a) that was not electrolyzed. Examples of downstream equipment include a reactor that produces methane from hydrogen and carbon monoxide according to the following reaction formula: 3H2 + CO → HO + CH4

[0024] Air 7a is supplied from air supply means 7 to the air electrode of stack 12 of solid oxide electrolysis cell 1. Oxygen generated at the interface with the air layer is sent to downstream equipment together with the air 7a. The air supply means 7 of this embodiment includes an air supply source 70, such as a blower, that supplies air 7a, a flow meter 71 that measures the flow rate of air 7a from the air supply source 70, and a third heater 72 that heats the air 7a as needed.

[0025] Heat exchange means 8 is provided between the water vapor supply means 3, the various gas supply means 4, and the air supply means 7 and the solid oxide electrolysis cell 1. The heat exchange means 8 in this embodiment includes a first heat exchanger 81, a fourth heater 82, a second heat exchanger 83, and a fifth heater 84. The first heat exchanger 81 is connected to the inlet and outlet of the anode of the stack 12 and performs heat exchange between the supply gas (fuel gas 2) supplied to the anode and the exhaust gas (hydrogen, carbon monoxide, and non-electrolyzed fuel gas 2) discharged from the anode. The fourth heater 82 is provided between the first heat exchanger 81 and the inlet of the anode and heats the supply gas supplied to the anode as needed. The second heat exchanger 83 is connected to the inlet and outlet of the cathode of the stack 12 and performs heat exchange between the supply gas (air 7a) supplied to the cathode and the exhaust gas (oxygen and air 7a) discharged from the cathode. The fifth heater 84 is provided between the second heat exchanger 83 and the inlet of the air electrode, and heats the supply gas supplied to the air electrode as needed.

[0026] Next, Figure 2 is a cross-sectional view of the solid oxide electrolysis cell 1 in Figure 1. The X, Y, and Z axes in the figure are mutually perpendicular. Although not limited thereto, the solid oxide electrolysis cell 1 may be arranged with the Y axis aligned vertically and the X and Z axes aligned horizontally. The direction in which the X axis extends may be referred to as the width direction, the direction in which the Y axis extends as the height direction, and the direction in which the Z axis extends as the depth direction.

[0027] As shown in Fig. 2 , the solid oxide electrolysis cell 1 of the electrolysis module of the present embodiment includes a stack exterior body 11 and a stack 12. The solid oxide electrolysis cell 1 may further include an outer casing 10.

[0028] The external housing 10 is a housing that surrounds the stack exterior body 11 and the stack 12. While FIG. 2 shows the external housing 10 in cross section, the external housing 10 surrounds the stack exterior body 11 and the stack 12 from above, below, front, back, left, and right. The terms "up, down," "front, back," "left, right," and related terms are used merely to facilitate understanding and correspond to the orientation of the drawings, and these terms do not necessarily limit the orientation of the stack exterior body 11, etc. (The same applies below). The external housing 10 may be made of a thermal insulating material. Examples of thermal insulating materials that constitute the external housing 10 include Roslim board. The wall thickness of the external housing 10 may be, for example, 100 to 150 mm, and the internal space of the external housing 10 may be, for example, 300 to 600 mm x 250 to 400 mm x 400 to 1100 mm.

[0029] The stack exterior body 11 is provided inside the external housing 10. The stack exterior body 11 may be made of heat-resistant steel. An example of the heat-resistant steel that constitutes the stack exterior body 11 is NCA-1 manufactured by Nippon Steel Stainless Steel Corporation. The wall thickness of the stack exterior body 11 may be, for example, 1.5 to 3 mm, and the outer dimensions of the stack exterior body 11 may be, for example, 200 to 300 mm x 150 to 300 mm x 200 to 400 mm. The stack exterior body 11 is disposed in the center of the internal space of the external housing 10 by a fixing member made of heat-resistant steel. The distance between the internal wall of the external housing 10 and the external wall of the stack exterior body 11 may be 10 mm or more and 150 mm or less. One or more stack exterior bodies 11 may be installed in the internal space of the external housing 10. The space formed between the internal wall of the external housing 10 and the external wall of the stack exterior body 11 is filled with gas discharged from the air electrode, thereby contributing to uniform heating of the stack exterior body.

[0030] The stack 12 is provided inside the stack exterior casing 11. As described above, the stack 12 includes a unit 120 in which multiple air electrodes (anode layers), multiple electrolyte layers, and multiple fuel electrodes (cathode layers) are stacked in this order, and interconnection plates 121 that connect the units together while sandwiching them from above and below. Fuel gas 2 (see FIG. 1) to the fuel electrodes is directly supplied to the stack 12 through a dedicated pipe 20 (see FIGS. 10 and 11). Meanwhile, air 7a (see FIG. 1) to the air electrodes is supplied to the inside of the stack exterior casing 11 through a dedicated pipe 21 (see FIGS. 10 and 11) and then supplied to the stack 12 inside the stack exterior casing 11. The air 7a supplied to the stack 12 passes through the inside of the stack exterior casing 11 and is exhausted into the space between the stack exterior casing 11 and the external casing 10. Providing the stack 12 inside the stack exterior casing 11 ensures a flow path for the air 7a, which advantageously enables temperature control of the stack 12 by adjusting the temperature of the air 7a.

[0031] Next, Fig. 3 is a perspective view showing the stack exterior body 11 and stack 12 of Fig. 2, Fig. 4 is a longitudinal cross-sectional view of the stack exterior body 11 and stack 12 taken along plane IV of Fig. 3, and Fig. 5 is a cross-sectional view of the stack exterior body 11 taken along line VV of Fig. 4. In Fig. 3, in order to show the interior of the stack exterior body 11, parts of the stack exterior body 11 (top plate 11t, one side plate 11s, and front plate 11f) are shown with imaginary lines (two-dot chain lines).

[0032] The stack exterior body 11 surrounds the stack 12 from above, below, behind, and to the left and right. The stack exterior body 11 has a bottom plate 11b disposed below the stack 12, a top plate 11t disposed above the stack 12, a pair of side plates 11s disposed on the left and right of the stack 12, a front plate 11f disposed in front of the stack 12, and a rear plate 11r disposed behind the stack 12. The height of the side plates 11s (the length in the Y-axis direction) is greater than the heights of the front plate 11f and the rear plate 11r. This is because the pair of side plates 11s are bolted to the stack exterior body 11 via a flange structure, making the side plates 11s removable.

[0033] As particularly shown in FIGS. 4 and 5 , a space S is provided between the stack exterior casing 11 and the outer periphery of the stack 12. The outer periphery of the stack 12 can be understood as the region outside the stack 12 along the X and Y axes between one end and the other end of the stack 12 along the Z axis. As described below, the Z axis also corresponds to the flow direction of air 7a supplied to the air electrode of the stack 12 and discharged from the air electrode. The space S is provided between the inner surfaces of the bottom plate 11b, top plate 11t, and side plate 11s and the outer surface of the stack 12. The separation distance between the bottom plate 11b, top plate 11t, and side plate 11s and the stack 12 may be 5 mm or more and 20 mm or less. A distance of 5 mm or more ensures a flow path for the air 7a in the space S, enabling advantageous temperature control of the stack 12 by adjusting the temperature of the air 7a. A distance of 20 mm or less improves the heat exchange efficiency with the stack 12 by adjusting the temperature of the air 7a.

[0034] In this embodiment, the space S is divided into multiple flow paths. In this embodiment, the space S is divided into multiple flow paths by multiple fin members 13 provided between the outer surface of the stack 12 and the inner surface of the stack exterior body 11. As particularly shown in FIG. 5 , the fin member 13 has a base 13a fixed to the outer surface of the stack 12 and multiple wall portions 13b erected from the base 13a. The wall portions 13b erect from both ends of the base 13a and an intermediate portion of the base 13a. The tips of the wall portions 13b abut against the inner surface of the stack exterior body 11. The wall portions 13b, the wall portions 13b, and the stack exterior body 11 define multiple flow paths. The flow paths extend in the Z-axis direction (the flow direction of the air 7a) around the outer periphery of the stack 12.

[0035] Next, Fig. 6 is an explanatory diagram showing the fluid flowing in the space S in Fig. 4, and Fig. 7 is a cross-sectional view of the stack outer casing 11 taken along line VII-VII in Fig. 6. Also, Fig. 8 is an explanatory diagram showing the gas supplied to the air electrode of the stack 12 in Fig. 6, and Fig. 9 is a cross-sectional view of the stack outer casing 11 taken along line IX-IX in Fig. 8. Note that Figs. 7 and 9 are also front views of the stack 12 as viewed from the upstream side along the flow direction of the gas (air 7a) supplied to the air electrode of the stack 12.

[0036] As shown in Figures 6 and 7, a temperature-controlled fluid is supplied to the space S. The fluid supplied to the space S is a branched gas supplied to the air electrode of the stack 12, as shown in Figures 8 and 9. In this embodiment, air 7a whose temperature is controlled by the second heat exchanger 83 and the fifth heater 84 (see Figure 1) is supplied to the air electrode of the stack 12 and the space S.

[0037] More specifically, as shown in FIGS. 6 and 8 , air 7a is supplied into the stack exterior casing 11 through an opening 11a provided in the rear plate 11r. The air 7a travels along the Z axis and collides with one end face 12a (upstream end face) of the stack 12. Although not shown in detail, the cathode inlets are provided as small openings distributed along one end face 12a of the stack 12. Some of the air 7a passes through the cathode through these openings and is discharged from the other end face 12b (downstream end face) of the stack 12 (see FIG. 8 ). Meanwhile, some of the air 7a that collides with one end face 12a (upstream end face) of the stack 12 spreads along the end face 12a and flows downstream through the space S (see FIG. 6 ). In this way, by supplying air 7a (a temperature-controlled fluid branched from the gas supplied to the cathode of the stack 12) to the space S provided between the stack exterior casing 11 and the stack 12, the temperature of the stack 12 can be controlled without relying on the electrolysis current, thereby improving the efficiency of the electrolysis reaction.

[0038] In the electrolysis module of this embodiment, the pressure of the gas supplied to the air electrode and the fuel electrode of the stack 12 may be 10 kPaG or more and less than 200 kPaG.

[0039] First, the above technology makes it possible to control the temperature of the stack 12 without relying on the electrolysis current. This means that temperature control is possible even if the pressure of the supply gas is reduced. In other words, the pressure of the supply gas, which was previously 0.2 to 0.9 MPaG, can now be reduced to 10 to 200 kPaG.

[0040] Since the pressure at the fuel electrode is approximately the same as the supply pressure at the air electrode via the electrolyte, the pressure at the fuel electrode can also be kept low. Furthermore, the mixed pressure of the various gases 4a and water vapor 3a on the fuel electrode side can also be kept low. Generally, when the pressure at the downstream stage of the pump is high, the influence of pump pulsation becomes strong, and the flow rates of the various gases 4a and water vapor 3a become unstable, resulting in the mixture ratio not reaching the theoretical value and performance deteriorating. However, by lowering the pressure, the mixture ratio can be made closer to the theoretical value.

[0041] Furthermore, by keeping the pressure at the anode (≒ vapor pressure) between 10 kPaG and 200 kPaG, the vapor temperature can be kept below 180°C. Here, in co-electrolysis, the mixing ratio of various gases 4a and water vapor 3a is an important factor affecting product quality, and accurate control of the vapor volume is required. Within this temperature range, highly reliable methods such as differential pressure and ultrasonic methods can be used to measure the vapor flow rate.

[0042] Next, Fig. 10 is an explanatory diagram showing a first mode of supplying the fuel gas 2 to the stack 12 of Fig. 9, and Fig. 11 is an explanatory diagram showing a second mode of supplying the fuel gas 2 to the stack 12 of Fig. 9. As shown in Figs. 10 and 11, the fuel gas 2 to the anode is directly supplied to the stack 12 through a dedicated pipe 20. On the other hand, the air 7a to the cathode is supplied to the inside of the stack outer casing 11 through a dedicated pipe 21, and then supplied to the stack 12 inside the stack outer casing 11.

[0043] The flow path of the space S is perpendicular to or opposite to the flow direction of the fuel gas 2 (gas supplied to the anode of the stack 12). A perpendicular configuration is shown in Fig. 10, and an opposite configuration is shown in Fig. 11. Providing the flow path of the space S in this manner and perpendicular to or opposite to the flow direction of the fuel gas 2 has the advantage of improving the electrolysis efficiency and heat exchange efficiency at the same time.

[0044] Second Embodiment Fig. 12 is a longitudinal cross-sectional view of a stack exterior body 11 and a stack 12 of an electrolysis module according to a second embodiment of the present invention, and Fig. 13 is a cross-sectional view of the stack exterior body 11 taken along line XIII-XIII in Fig. 12. In the first embodiment, the space S to which a temperature-controlled fluid is supplied has been described as being provided between the stack exterior body 11 and the stack 12. However, the space S to which a temperature-controlled fluid is supplied may be provided in another location.

[0045] 12 and 13 show an embodiment in which a space S to which a temperature-controlled fluid is supplied is further provided inside the stack 12. In this embodiment, a spacer 14 is provided inside the stack 12, and the spacer 14 has a plurality of flow paths extending in the flow direction of the temperature-controlled fluid (air 7a). The spacer 14 is arranged so as to overlap the air electrode, electrolyte layer, and fuel electrode (cathode layer) in the stack 12. In the embodiment shown in FIGS. 12 and 13, the space S is provided both between the stack outer casing 11 and the stack 12 and inside the stack 12, but the space S provided on the outer periphery of the stack 12 may be omitted. The rest is the same as in embodiment 1.

[0046] Embodiment 3. Figure 14 is an explanatory diagram schematically illustrating an electrolysis module according to Embodiment 3 of the present invention. As shown in Figure 14, the electrolysis module may further include a flow path switch 9 that is disposed between the outlet of the air electrode of the stack 12 and the second heat exchanger 83 and is configured to switch the flow path between a flow path leading to the second heat exchanger 83 and a flow path that bypasses the second heat exchanger 83.

[0047] The second heat exchanger 83 is effective in improving thermal efficiency when the temperature of the stack 12 is rising. However, during steady-state operation of the stack 12, when the average temperature of the stack 12 is controlled by the air temperature and flow rate, if the average temperature of the stack 12 is lower than the set temperature, the outlet temperature of the fifth heater 84 is increased to control the average temperature of the stack 12 toward the rising side. On the other hand, if the average temperature of the stack 12 is higher than the set temperature, the outlet temperature of the fifth heater 84 must be decreased to control the average temperature of the stack 12 toward the falling side. However, because the outlet temperature of the fifth heater 84 is affected by the second heat exchanger 83, it takes time to lower the outlet temperature of the fifth heater 84, resulting in a time delay and making it difficult to control the temperature of the stack 12. In other words, when the temperature of the stack 12 is rising, the temperature is raised by effectively utilizing the exhaust heat of the stack 12 via the second heat exchanger 83, and by bypassing the second heat exchanger 83 during electrolysis, the inlet temperature of the air electrode of the stack 12 can be directly linked to the set temperature of the fifth heater 84. This allows the temperature of the stack 12 during electrolysis to be accurately controlled by the fifth heater 84. Furthermore, the temperature of the stack 12 can be lowered more quickly.

[0048] Next, Fig. 15 is a cross-sectional view of the flow path switch 9 of Fig. 14. As shown in Fig. 15, the flow path switch 9 has a housing 90 and a movable body 91. The housing 90 has a first connection part 90a connected to a pipe leading to the inlet of the air electrode of the stack 12, a second connection part 90b connected to a pipe leading to the second heat exchanger 83, and a third connection part 90c connected to a pipe for bypassing the second heat exchanger 83. The movable body 91 is rotatably provided inside the housing 90 and can take a position that closes the second connection part 90b, a position that closes the third connection part 90c, and an intermediate position therebetween.

[0049] Next, Figure 16 is an explanatory diagram showing the operation of the flow path switch 9 of Figure 15. As shown in Figure 16, when the temperature of the stack 12 is rising, the movable body 91 of the flow path switch 9 is in a position that closes the third connection part 90c, and the fluid from the air electrode of the stack 12 is directed to the second heat exchanger 83. When the temperature of the stack 12 is completely rising, the movable body 91 of the flow path switch 9 is in an intermediate position, and a portion of the fluid from the air electrode of the stack 12 is directed to the second heat exchanger 83, and the remainder bypasses the second heat exchanger 83. When the stack 12 is being electrolyzed or cooled, the movable body 91 of the flow path switch 9 is in a position that closes the second connection part 90b, and the fluid from the air electrode of the stack 12 bypasses the second heat exchanger 83. The other configurations are the same as those of the first and second embodiments.

[0050] Although the preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, the present invention is not limited to these examples. It is clear that a person skilled in the art to which the present invention pertains can conceive of various modifications and alterations within the scope of the technical ideas set forth in the claims, and it is understood that these also naturally fall within the technical scope of the present invention.

[0051] 9: Flow path switch 10: External housing 11: Stack exterior body 12: Stack S: Space

Claims

1. An electrolysis module comprising: a stack exterior body; a stack provided inside the stack exterior body; and a space provided between the stack exterior body and the outer periphery of the stack and / or inside the stack, wherein a temperature-controlled fluid is supplied to the space, and the fluid is a branch of a gas supplied to an air electrode of the stack.

2. The electrolysis module according to claim 1, wherein the space is divided into a plurality of flow paths.

3. The electrolysis module according to claim 2, wherein the flow path is perpendicular to or opposite to the flow direction of the gas supplied to the fuel electrode of the stack.

4. An electrolysis module according to any one of claims 1 to 3, wherein co-electrolysis is carried out in the stack.

5. The electrolysis module according to any one of claims 1 to 3, further comprising: a heat exchanger connected to the inlet and outlet of the air electrode of the stack for exchanging heat between a supply gas supplied to the air electrode and an exhaust gas exhausted from the air electrode; and a flow path switcher disposed between the outlet of the air electrode and the heat exchanger, configured to switch a flow path between a flow path leading to the heat exchanger and a flow path bypassing the heat exchanger.

6. The electrolysis module according to any one of claims 1 to 3, wherein the pressure of the gas supplied to the air electrode and the fuel electrode of the stack is 10 kPaG or more and less than 200 kPaG.

Images