Carbon dioxide recovery device

Abstract

To provide a CO2 recovery device which can improve CO2 recovery efficiency.SOLUTION: A CO2 recovery device includes a housing 10 and a plurality of electrochemical cells 20. The electrochemical cell 20 has an action electrode 21, a counter electrode 22, a separator 23, a frame 24 and a plurality of projections 25. The plurality of electrochemical cells 20 is stored in the housing 10 in a state in which a load is applied thereto in a lamination direction. The plurality of projections 25 provided on the frame 24 of the predetermined electrochemical cell 20 is brought into contact with the action electrode 21 of the different electrochemical cell 20 adjacent to the predetermined electrochemical cell 20 in the lamination direction. Thereby, a gas passage 30 is formed between the frame 24 of the predetermined electrochemical cell 20 and the action electrode 21 of the different electrochemical cell 20.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present disclosure relates to a carbon dioxide (hereinafter referred to as "CO2") recovery device that recovers CO2 from a gas containing CO2. [Background technology]

[0002] The CO2 capture device described in Patent Document 1 includes an electrochemical cell that is composed of a working electrode as one electrode containing a CO2 adsorbent, a counter electrode as the other electrode containing an electroactive auxiliary material, and a separator provided between the working electrode and the counter electrode. This CO2 capture device is configured to apply a voltage so that the working electrode has a lower potential than the counter electrode, and to adsorb CO2 to the working electrode. In the following description, the electrochemical cell may be simply referred to as a "cell." [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-72977 A Summary of the Invention [Problem to be solved by the invention]

[0004] Generally, a CO2 capture device is configured by stacking a plurality of cells inside a housing. The CO2 capture device flows a gas containing CO2 (hereinafter, referred to as a "CO2-containing gas") through a gas flow path formed between the stacked cells, and captures CO2 from the CO2-containing gas.

[0005] However, as a result of detailed investigation by the inventor, the following problem was found in the CO2 capture device. That is, the working electrode, the counter electrode, and the separator are all made of flexible materials and formed in a thin plate shape, and are curved in a natural state without being corrected in shape. Therefore, the gas flow path between the multiple cells stacked inside the housing becomes narrow, and the flow rate of the CO2-containing gas flowing through the gas flow path decreases. In addition, if proper positioning or uniform load cannot be applied during stacking, the electrical resistance value of the cells increases, and the amount of current that flows when a voltage is applied to the working electrode and the counter electrode decreases. This causes a problem of a decrease in the efficiency of CO2 adsorption by the working electrode.

[0006] In view of the above, an object of the present disclosure is to provide a CO2 recovery device capable of improving the CO2 recovery efficiency. [Means for solving the problem]

[0007] According to one aspect of the present disclosure, a CO2 capture device for capturing CO2 from a CO2-containing gas includes: a housing (10) having a gas inlet (15) and a gas outlet (16); A plurality of plate-shaped cells (20) stacked inside a housing, The cell is A working electrode (21) as one electrode for depositing CO2; a counter electrode (22) as the other electrode containing an electroactive auxiliary material; A separator (23) provided between the working electrode and the counter electrode; A frame (24) on which the working electrode, the counter electrode and the separator are mounted; a plurality of protrusions (25) provided on a surface of the frame opposite to a surface on which the working electrode, the counter electrode, and the separator are placed; The cells are housed in a housing with a load applied in the stacking direction, A plurality of protrusions provided on the frame of a specified cell abut against the working electrode of another cell adjacent to the specified cell in the stacking direction, and a gas flow path (30) through which the CO2-containing gas flows is formed between the frame of the specified cell and the working electrode of the other cell.

[0008] According to this, the multiple protrusions provided on the frame of a specific cell come into contact with the working electrode of another cell adjacent in the stacking direction, correcting the shape of those cells to a flat shape. Therefore, the gas flow path between the frame of the specific cell and the working electrode of the other cell can be widened. Therefore, the CO2 capture device can increase the flow rate of the CO2-containing gas flowing through the gas flow path, and improve the CO2 capture efficiency. In addition, the electrical resistance of the cell can be reduced by applying a load to the cell using multiple protrusions. Therefore, the CO2 capture device can increase the amount of current that flows when a voltage is applied between the working electrode and the counter electrode, improving the efficiency of CO2 capture.

[0009] Note that the reference symbols in parentheses attached to each component indicate an example of the correspondence between the component and specific components described in the embodiments described below. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic configuration diagram of a CO2 capture system in which a CO2 capture device according to a first embodiment is used. [Diagram 2] FIG. 1 is a perspective view of a CO2 recovery device according to a first embodiment. [Diagram 3] 3 is a front view of the CO2 recovery device as seen from the arrow III in FIG. 2. [Figure 4] FIG. 2 is a perspective view of a housing provided in the CO2 recovery device. [Diagram 5] FIG. 2 is an exploded perspective view of a cell provided in the CO2 capture device. [Figure 6] 6 is a view showing the bottom surface of the frame and the protrusions as viewed from the arrow VI in FIG. 5. [Figure 7] FIG. 2 is an explanatory diagram for explaining the function of a cell included in the CO2 recovery device. [Figure 8] 8 is a view showing a frame and a protrusion as viewed from the arrow VIII in FIG. 5 and FIG. 6. [Figure 9] FIG. 9 is an enlarged view of a portion XI in FIG. 8. [Figure 10]4 is a perspective view of a plurality of cells provided in the CO2 capture device in the portion X in FIG. 3. [Figure 11] FIG. 2 is a cross-sectional view of a plurality of cells provided in the CO2 capture device. [Figure 12] FIG. 11 is a perspective view showing a protrusion in a CO2 recovery device according to a second embodiment. [Figure 13] 11 is a diagram showing a frame and a protrusion in a CO2 recovery device according to a second embodiment. FIG. [Figure 14] 13 is a diagram showing a frame and a protrusion in a CO2 recovery device according to a third embodiment. FIG. [Figure 15] FIG. 11 is a perspective view showing a protrusion in a CO2 recovery device according to a fourth embodiment. [Figure 16] 13 is a diagram showing a frame and a protrusion in a CO2 recovery device according to a fourth embodiment. FIG. [Figure 17] FIG. 13 is a diagram showing a frame and a protrusion in a CO2 recovery device according to a fifth embodiment. [Figure 18] FIG. 13 is a perspective view showing a protrusion in a CO2 recovery device according to a sixth embodiment. [Figure 19] FIG. 13 is a diagram showing a frame and a protrusion in a CO2 recovery device according to a sixth embodiment. [Figure 20] FIG. 13 is a perspective view showing a protrusion in a CO2 recovery device according to a seventh embodiment. [Figure 21] FIG. 13 is a diagram showing a frame and protrusions in a CO2 recovery device according to a seventh embodiment. [Figure 22] FIG. 13 is a diagram showing a frame and protrusions in a CO2 recovery device according to an eighth embodiment. [Figure 23] FIG. 13 is a diagram showing a frame and protrusions in a CO2 recovery device according to a ninth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals, and the description thereof will be omitted.

[0012] (First Embodiment) The first embodiment will be described with reference to the drawings. <Configuration of CO2 Recovery System> As shown in FIG. 1, the CO2 recovery apparatus 1 of the first embodiment is used, for example, in a CO2 recovery system 2. The CO2 recovery system 2 includes a pump 3, a CO2 recovery apparatus 1, a flow path switching valve 4, a CO2 utilization apparatus 5, a control apparatus 6, and the like.

[0013] The pump 3 supplies a CO2-containing gas to the CO2 recovery apparatus 1 and discharges a CO2-removed gas or CO2 from the CO2 recovery apparatus 1. As the CO2-containing gas, for example, air or exhaust gas of an internal combustion engine is used.

[0014] The CO2 recovery apparatus 1 is an apparatus that separates and recovers CO2 from a CO2-containing gas. The CO2 recovery apparatus 1 discharges the CO2-removed gas after recovering CO2 from the CO2-containing gas. Further, the CO2 recovery apparatus 1 can discharge the CO2 recovered from the CO2-containing gas. The configuration of the CO2 recovery apparatus 1 will be described later.

[0015] The flow path switching valve 4 is a three-way valve that switches the flow path of the exhaust gas (that is, the CO2-removed gas or CO2) discharged from the CO2 recovery apparatus 1. When the CO2-removed gas is discharged from the CO2 recovery apparatus 1, the flow path switching valve 4 switches the flow path of the exhaust gas to the atmosphere side. On the other hand, when CO2 is discharged from the CO2 recovery apparatus 1, the flow path switching valve 4 switches the flow path of the exhaust gas to the CO2 utilization apparatus 5 side.

[0016] As the CO2 utilization apparatus 5, for example, a storage tank for storing CO2 or an apparatus for converting CO2 into a hydrocarbon fuel such as methane can be used.

[0017] The control apparatus 6 is composed of a well-known microcomputer and peripheral circuits. The control apparatus 6 executes various arithmetic processes and controls the operations of the pump 3, the CO2 recovery apparatus 1, the flow path switching valve 4, and the like.

[0018] <Configuration of the CO₂ Recovery Device> Next, the CO₂ recovery device 1 of the first embodiment will be described.

[0019] As shown in FIG. 2, the CO₂ recovery device 1 includes a housing 10 and a plurality of electrochemical cells 20 (hereinafter referred to as "cells 20") disposed inside the housing 10. Each cell 20 is formed in a plate shape and is disposed inside the housing 10 in a stacked state. In each figure, the direction in which the plurality of cells 20 are stacked, that is, the stacking direction, is indicated by an arrow LD. Hereinafter, for convenience of explanation, one of the stacking directions will be referred to as "up" and the other as "down", but the installation state of the CO₂ recovery device 1 is not limited.

[0020] <Configuration of the Housing> As shown in FIGS. 2 to 4, the housing 10 has a bottom portion 11, a lid portion 12, and four support columns 13, and is formed in a rectangular parallelepiped shape. A plurality of cells 20 are placed on the bottom portion 11 in a stacked state. Therefore, the lowermost one of the plurality of cells 20 is in contact with the bottom portion 11. As shown in FIG. 4, a plurality of holes 14 are provided in the bottom portion 11. These plurality of holes 14 will be described later.

[0021] The four support columns 13 are provided at the corner portions of the bottom portion 11 and extend in the stacking direction. The four support columns 13 connect the bottom portion 11 and the lid portion 12. Hereinafter, for convenience of explanation, the four support columns 13 may be referred to as a first support column 131, a second support column 132, a third support column 133, and a fourth support column 134 in order in one direction on the outer periphery of the bottom portion 11.

[0022] As shown in FIGS. 2 to 4, the lid portion 12 is provided at a position facing the bottom portion 11 with the plurality of cells 20 interposed therebetween. The lid portion 12 is fixed to the support column 13 while applying a load to the plurality of cells 20 in the stacking direction. Therefore, the plurality of cells 20 are accommodated in the housing 10 while a load is applied in the stacking direction.

[0023] The housing 10 has a gas inlet 15 and a gas outlet 16. The area of ​​the housing 10 surrounded by the first support 131, the second support 132, the bottom 11, and the lid 12 constitutes the gas inlet 15. A CO2-containing gas is supplied to the gas inlet 15. The area of ​​the housing 10 surrounded by the third support 133, the fourth support 134, the bottom 11, and the lid 12 constitutes the gas outlet 16. The CO2-removed gas or CO2 is discharged from the gas outlet 16.

[0024] For ease of explanation, the direction connecting the center of gas inlet 15 and the center of gas outlet 16 of housing 10 is referred to as the first direction, and the direction perpendicular to the first direction and perpendicular to the stacking direction is referred to as the second direction. In each drawing, the first direction is indicated by an arrow D1, and the second direction is indicated by an arrow D2.

[0025] <Cell configuration> Fig. 5 is an exploded perspective view of one of the multiple cells 20 housed inside the housing 10. As shown in Fig. 5 and Fig. 6, the cell 20 has a working electrode 21, a counter electrode 22, a separator 23, a frame 24, and multiple protrusions 25. An ion-conductive material (not shown) is provided between the working electrode 21, the counter electrode 22, and the separator 23.

[0026] The working electrode 21 is formed by applying a mixture of a working electrode side conductive material and a working electrode side binder to a working electrode side substrate. The working electrode side substrate is a porous conductive material. The CO2 adsorbent may be applied to the working electrode 21. The CO2 adsorbent adsorbs CO2 by receiving electrons and releases the adsorbed CO2 by releasing electrons. For example, polyanthraquinone can be used as the CO2 adsorbent.

[0027] The working electrode side conductive material forms a conductive path to the CO2 adsorbent. As the working electrode side conductive material, for example, a carbonaceous material such as carbon nanotubes, carbon black, graphene, etc. can be used.

[0028] The working electrode side binder is provided to hold the CO2 adsorbent and the working electrode side conductive material on the working electrode side base material. As the working electrode side binder, for example, a conductive resin can be used. As the conductive resin, an epoxy resin containing Ag or the like as a conductive filler, polytetrafluoroethylene (PTFE), fluororesin such as polyvinylidene fluoride (PVDF), etc. can be used.

[0029] The counter electrode 22 is formed by applying an electroactive auxiliary material, a counter electrode conductive material, and a counter electrode binder in a mixture state to a counter electrode substrate. The electroactive auxiliary material is an auxiliary electroactive species that transfers electrons between the working electrode 21 and the CO2 adsorbent. As the electroactive auxiliary material, for example, a metal complex that allows electron transfer by changing the valence of the metal ion can be used. Examples of such metal complexes include cyclopentadienyl metal complexes such as ferrocene, nickelocene, and cobaltocene, and porphyrin metal complexes. These metal complexes may be polymers or monomers.

[0030] The counter electrode side conductive material, the counter electrode side binder, and the counter electrode side substrate have the same configuration as the working electrode side conductive material, the working electrode side binder, and the working electrode side substrate.

[0031] The separator 23 is disposed between the working electrode 21 and the counter electrode 22, and separates the working electrode 21 from the counter electrode 22. The separator 23 is an insulating ion-permeable membrane that prevents physical contact between the working electrode 21 and the counter electrode 22 to suppress electrical short-circuiting and allows ions to pass through. The separator 23 may be a cellulose membrane, a polymer, or a composite material of a polymer and ceramic.

[0032] The ion conductive material is provided between the working electrode 21 and the counter electrode 22 via the separator 23. The ion conductive material is in contact with the CO2 adsorbent. The ions contained in the ion conductive material promote the electron attraction of the CO2 adsorbent when the CO2 adsorbent bonds with CO2. The ions contained in the ion conductive material do not directly react with the functional group contained in the CO2 adsorbent that bonds with CO2.

[0033] The ion-conductive material may be an electrolytic solution, a solid electrolyte, or the like. The electrolytic solution is a liquid salt that is nonvolatile at room temperature and normal pressure. When an electrolytic solution is used as the ion-conductive material, the electrolytic solution may be gelled to prevent elution from the cell 20. When a solid electrolyte is used as the ion-conductive material, it is desirable to use an ionomer made of a polymer electrolyte or the like to increase the contact area with the CO2 adsorbent.

[0034] As the electrolyte, for example, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([EMIM][Tf2N]), 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([BMIM][Tf2N]), 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]), etc. can be used.

[0035] 7, the working electrode 21 and the counter electrode 22 of the cell 20 are connected to a power source 7. The power source 7 applies a predetermined voltage to the working electrode 21 and the counter electrode 22, and can change the potential difference between the working electrode 21 and the counter electrode 22. The working electrode 21 is a negative electrode, and the counter electrode 22 is a positive electrode.

[0036] The cell 20 can be operated in a CO2 capture mode in which CO2 is captured by the working electrode 21, and a CO2 release mode in which CO2 is released from the working electrode 21, by changing the potential difference between the working electrode 21 and the counter electrode 22. The CO2 capture mode is a charge mode in which the cell 20 is charged, and the CO2 release mode is a discharge mode in which the cell 20 is discharged.

[0037] In the CO2 capture mode, a first voltage V1 is applied between the working electrode 21 and the counter electrode 22, and electrons are supplied from the counter electrode 22 to the working electrode 21. At the first voltage V1, the potential of the working electrode 21 is less than the potential of the counter electrode 22. The first voltage V1 can be set within a range of, for example, 0.3 to 3.0 V, and preferably 0.5 to 2.0 V.

[0038] On the other hand, in the CO2 release mode, a second voltage V2 is applied between the working electrode 21 and the counter electrode 22, and electrons are supplied from the working electrode 21 to the counter electrode 22. The second voltage V2 is a voltage different from the first voltage V1. The second voltage V2 may be a voltage lower than the first voltage V1, and the magnitude relationship between the working electrode potential and the counter electrode potential is not limited. That is, in the CO2 release mode, the working electrode potential may be less than the counter electrode potential, the working electrode potential may be equal to the counter electrode potential, or the working electrode potential may be greater than the counter electrode potential.

[0039] <Explanation of frame and protrusions> As shown in Figs. 5, 6 and 8 to 11, the frame 24 is formed in a dish shape, and has a bottom plate 26 and side plates 27. The bottom plate 26 is formed in a plate shape. The side plates 27 are provided so as to surround the outer edge of the bottom plate 26. The working electrode 21, the counter electrode 22 and the separator 23 are placed inside the frame 24, and are immersed in the electrolyte. The frame 24 is formed of a material having high formability, such as polypropylene (PP).

[0040] Incidentally, the above-mentioned working electrode 21, counter electrode 22, separator 23, and frame 24 are all made of flexible material and formed into a plate shape, and are curved in a natural state without being corrected in shape. Therefore, when the gas flow path 30 between the multiple cells 20 stacked inside the housing 10 becomes narrow, the flow rate of the CO2-containing gas flowing through the gas flow path 30 decreases. In addition, when the electrical resistance value of the cell 20 increases, the amount of current that flows when a voltage is applied to the working electrode 21 and the counter electrode 22 decreases. This causes a problem that the efficiency of adsorption of CO2 by the working electrode 21 decreases.

[0041] Therefore, the CO2 recovery device 1 has a plurality of protrusions 25 on the surface of the bottom plate 26 of the frame 24 opposite to the side on which the working electrode 21, the counter electrode 22, and the separator 23 are placed. The plurality of protrusions 25 and the frame 24 are integrally formed by, for example, resin injection molding.

[0042] 6, in the first embodiment, each of the protrusions 25 has a shape in which the length L1 in the first direction is longer than the length L2 in the second direction when viewed from the normal direction of the bottom plate 26 of the frame 24, i.e., the stacking direction. In the first embodiment, each of the protrusions 25 is a rectangle having a long side in the first direction.

[0043] The multiple protrusions 25 are arranged in a lattice pattern on the bottom plate 26 of the frame 24. In other words, the multiple protrusions 25 are lined up on the bottom plate 26 of the frame 24 in the first direction and also lined up in the second direction.

[0044] 6, the protrusions 25 are arranged at intervals in the second direction so as to form a linear flow path in the first direction. This is the same in the second to eighth embodiments described later.

[0045] As described above, in the first embodiment, each of the protrusions 25 has a shape having a long side in the first direction. In addition, the multiple protrusions 25 are arranged at intervals in the second direction on the bottom plate 26 of the frame 24, and a linear flow path is formed in the first direction. This prevents the flow of the CO2-containing gas flowing through the gas flow path 30 from becoming turbulent, and brings the gas flow closer to a straight flow, thereby reducing the pressure loss of the CO2-containing gas. Therefore, the CO2 recovery device 1 can increase the flow rate of the CO2-containing gas flowing through the gas flow path 30 and improve the recovery efficiency of CO2.

[0046] As shown in FIG. 10 and FIG. 11, in a state where a plurality of cells 20 are stacked, a plurality of protrusions 25 provided on the frame 24 of a predetermined cell 20 abuts against the working electrode 21 of another cell 20 adjacent to the predetermined cell 20 in the stacking direction. Therefore, all of the plurality of cells 20 are corrected to a flat shape by the plurality of protrusions 25. Therefore, a gas flow path 30 through which a CO2-containing gas flows is formed between the frame 24 of the predetermined cell 20 and the working electrode 21 of the other cell 20. The height of the plurality of protrusions 25 is set to a height (for example, about 0.2 to 50 mm, preferably about 0.5 to 10 mm) that can sufficiently secure the flow path area of ​​the gas flow path 30. In the present disclosure, a flat shape refers to a substantially flat shape including a slight curve or unevenness in addition to a completely flat surface.

[0047] Among the side plates 27 of the frame 24, the one having the first direction as a normal line is called the first side plate 271, and the one having the second direction as a normal line is called the second side plate 272. The height H1 of the first side plate 271 is formed slightly higher than the total thickness of the working electrode 21, the counter electrode 22, the separator 23, and the bottom plate 26 in a state where they are straightened to a flat shape. Therefore, the first side plate 271 suppresses leakage of the electrolyte. In addition, the height H2 of the second side plate 272 is formed to be approximately the same height as the total thickness of the working electrode 21, the counter electrode 22, the separator 23, the bottom plate 26, and the protrusion 25 in a state where they are straightened to a flat shape. Therefore, the CO2-containing gas flowing through the gas flow path 30 is suppressed from leaking between the second side plates 272 overlapping in the stacking direction.

[0048] As described above, the lid 12 of the housing 10 is fixed to the support 13 in a state in which a load is applied to the multiple cells 20 in the stacking direction. Specifically, the lid 12 of the housing 10 applies a load to the cell 20 adjacent to the lid 12 in the stacking direction, i.e., the uppermost cell 20. The load is transmitted from the multiple protrusions 25 of a specific cell 20 to another cell 20 adjacent to the specific cell 20 on the lower side in the stacking direction. In this way, the load applied from the lid 12 of the housing 10 to the uppermost cell 20 is transmitted in sequence to the cell 20 on the lower side in the stacking direction, and then transmitted to the cell 20 adjacent to the bottom 11 in the stacking direction, i.e., the lowermost cell 20.

[0049] As shown in Fig. 4, the bottom 11 of the housing 10 has a plurality of holes 14. The plurality of protrusions 25 of the lowest cell 20 among the plurality of stacked cells 20 are adapted to fit into the plurality of holes 14 provided in the bottom 11 of the housing 10. Therefore, the frame 24 of the lowest cell 20 can be brought into contact with the bottom 11 of the housing 10, eliminating unnecessary space and allowing more cells 20 to be provided in the housing 10 by that amount.

[0050] As shown in Figs. 10 and 11, the plurality of protrusions 25 of each of the plurality of stacked cells 20 are arranged in a straight line in the stacking direction. This makes it possible to prevent the cell 20 from curving and the protrusions 25 from buckling. The plurality of protrusions 25 can also reliably transmit a load from a given cell 20 to another cell 20 adjacent in the stacking direction. Therefore, the plurality of protrusions 25 can correct the shape of the cell 20 to a flat shape and prevent the gas flow path 30 from narrowing at any point. The plurality of protrusions 25 can also apply a substantially uniform surface pressure to each of the plurality of stacked cells 20, thereby reducing the electrical resistance of the cell 20.

[0051] Here, as shown in FIG. 9 , in each protrusion 25, the portion that connects to the frame 24 is referred to as the frame connection portion 251, the portion that abuts against the working electrode 21 of the cell 20 is referred to as the abutment portion 252, and the surface that connects the frame connection portion 251 and the abutment portion 252 is referred to as the protrusion side surface 253.

[0052] As shown in FIG. 9 to FIG. 11, each of the protrusions 25 has a shape in which the protrusion side surface 253 gradually approaches the center CL of the protrusion 25 from the frame connection portion 251 side toward the abutment portion 252 side. In other words, when viewed from a direction perpendicular to the stacking direction (i.e., the first direction and the second direction) or in a cross-sectional view parallel to the stacking direction, each of the protrusions 25 has a trapezoidal shape. When viewed from a direction perpendicular to the stacking direction (i.e., the first direction and the second direction) or in a cross-sectional view parallel to the stacking direction, each of the protrusions 25 has a tapered shape in which the protrusion side surface 253 gradually approaches the center CL of the protrusion 25. Furthermore, each of the protrusions 25 has a curved end 254 on the abutment portion 252 side. This makes it possible to reduce the area where the abutment portion 252 of the protrusion 25 contacts the working electrode 21, and increase the area of ​​the working electrode 21 exposed to the gas flow path 30, thereby improving the CO2 capture capacity.

[0053] Incidentally, when multiple cells 20 are stacked, the central position of the protrusion 25 of a given cell 20 and the central position of the protrusion 25 of another cell 20 may be slightly shifted from a state in which they are aligned in a straight line in the stacking direction due to manufacturing tolerances, etc. In that case, if the multiple protrusions 25 are made rectangular rather than trapezoidal, stress will be concentrated only in the portions of the protrusions 25 where the protrusions 25 overlap each other when viewed from the stacking direction, and the protrusions 25 may buckle or bend.

[0054] In contrast, as described above, in the first embodiment, each of the protrusions 25 is trapezoidal. This prevents the abutment portion 252 of the protrusion 25 of the predetermined cell 20 from shifting outwardly from the frame connection portion 251 of the protrusion 25 of the other cell 20 when viewed from the stacking direction, even if the central position of the protrusion 25 of a certain cell 20 is slightly shifted from the central position of the protrusion 25 of another cell 20 in the stacking direction. This prevents stress from concentrating on only a portion of the protrusion 25, and prevents the protrusion 25 from buckling.

[0055] In addition, the interval P1 between the adjacent protrusions 25 in the in-plane direction of the bottom plate 26 of the frame 24 of a given cell 20 is set so that the surface pressure per unit area applied to another cell 20 adjacent to the given cell 20 in the stacking direction is uniform. Specifically, the interval P1 between the adjacent protrusions 25 in the in-plane direction of the bottom plate 26 of the frame 24 is set so that the surface pressure of the intermediate portion 202 between the adjacent protrusions 25 in the cell 20 is 70% or more of the surface pressure of the portion 201 where the protrusions 25 are provided in the cell 20. As a result, the CO2 recovery device 1 can reduce the electrical resistance value of the cell 20, thereby increasing the amount of current flowing through the cell 20 and improving the recovery efficiency of CO2. As shown in FIG. 6, the interval P1 between the adjacent protrusions 25 in the first direction on the bottom plate 26 of the frame 24 and the interval P2 between the adjacent protrusions 25 in the second direction are both set so that the surface pressure per unit area applied to the cell 20 is uniform.

[0056] <Effects of the First Embodiment> The CO2 recovery device 1 of the first embodiment described above provides the following advantages.

[0057] (1) The CO2 recovery device 1 of the first embodiment is configured such that a plurality of protrusions 25 provided on the frame 24 of a predetermined cell 20 abuts against the working electrode 21 of another cell 20 adjacent to the cell in the stacking direction, and a gas flow path 30 is formed between the frame 24 of the predetermined cell 20 and the working electrode 21 of the other cell 20. According to this, the multiple protrusions 25 of a given cell 20 come into contact with another cell 20 adjacent in the stacking direction, correcting the shape of those cells 20 to a flat shape. Therefore, it is possible to widen the gas flow path 30 between the frame 24 of the given cell 20 and the working electrode 21 of the other cell 20. Therefore, the CO2 recovery device 1 can increase the flow rate of the CO2-containing gas flowing through the gas flow path 30, and improve the CO2 recovery efficiency. In addition, the electrical resistance of the cell 20 can be reduced by applying a load to the cell 20 using the multiple protrusions 25. Therefore, the CO2 recovery device 1 can increase the amount of current that flows when a voltage is applied to the working electrode 21 and the counter electrode 22, thereby improving the CO2 recovery efficiency.

[0058] (2) In the first embodiment, the plurality of protrusions 25 of each of the plurality of stacked cells 20 are arranged linearly in the stacking direction. According to this, if the multiple protrusions 25 of each of the multiple cells 20 are not arranged linearly in the stacking direction, the cell 20 may be curved or the protrusions 25 may buckle due to the load, resulting in the occurrence of locations where the gas flow path 30 becomes narrow. In addition, the load will not be reliably transmitted from a given cell 20 to another cell 20 adjacent in the stacking direction via the protrusions 25. In contrast, in the first embodiment, the multiple protrusions 25 of each of the multiple stacked cells 20 are arranged linearly in the stacking direction, so that when a load is applied to the multiple cells 20 in the stacking direction, the cells 20 are prevented from bending and the protrusions 25 are prevented from buckling. This makes it possible to prevent the gas flow path 30 from narrowing at certain points. Furthermore, the multiple protrusions 25 can apply a substantially uniform surface pressure to each of the multiple stacked cells 20, thereby reducing the electrical resistance of the cells 20. Therefore, the CO2 recovery device 1 can widen the gas flow path 30 and increase the amount of current flowing through the cells 20, thereby improving the CO2 recovery efficiency.

[0059] (3) In the first embodiment, the intervals P1, P2 between adjacent protrusions 25 in the frame 24 are set so that the surface pressure per unit area applied to the cell 20 is uniform. As a result, the CO2 recovery device 1 can reduce the electrical resistance of the cell 20 by suppressing the variation in the surface pressure applied to the cell 20 from the multiple protrusions 25, thereby increasing the amount of current flowing through the cell 20 and improving the CO2 recovery efficiency. In addition, the surface pressure per specified unit area of ​​cell 20 being uniform means that the surface pressure of intermediate portion 202 between adjacent protrusions 25 in cell 20 is 70% or more of the surface pressure of portion 201 in cell 20 where protrusion 25 is provided.

[0060] (4) In the first embodiment, the spacings P1, P2 between adjacent protrusions 25 in the frame 24 are set so that the surface pressure of the intermediate portion 202 between adjacent protrusions 25 in the cell 20 is 70% or more of the surface pressure of the portion 201 in the cell 20 where the protrusions 25 are provided. According to this, the CO2 recovery device 1 applies a uniform surface pressure to the cell 20 and reduces the electrical resistance value of the cell 20, thereby increasing the amount of current flowing through the cell 20 and improving the CO2 recovery efficiency.

[0061] (5) In the first embodiment, the multiple protrusions 25 are arranged at intervals in the second direction so as to form a linear flow path in the first direction. According to this, the CO2 recovery device 1 reduces the pressure loss in the gas flow passage 30 and increases the flow rate of the CO2-containing gas flowing through the gas flow passage 30, thereby improving the CO2 recovery efficiency.

[0062] (6) In the first embodiment, the plurality of protrusions 25 have a shape in which the length L1 in the first direction is longer than the length L2 in the second direction when viewed in the stacking direction. This makes it possible to prevent the flow of the CO2-containing gas flowing through the gas flow passage 30 from becoming turbulent, to make the gas flow closer to a straight flow, and to reduce the pressure loss of the CO2-containing gas flowing through the gas flow passage 30. Therefore, the CO2 recovery device 1 can increase the flow rate of the CO2-containing gas flowing through the gas flow passage 30 and improve the CO2 recovery efficiency.

[0063] (7) In the first embodiment, the multiple protrusions 25 have a rectangular cross section perpendicular to the stacking direction. According to this, the shape of the plurality of protrusions 25 can be set arbitrarily.

[0064] (8) In the first embodiment, the multiple protrusions 25 are arranged in a lattice pattern. According to this, the arrangement of the multiple protrusions 25 can be set arbitrarily.

[0065] (9) In the first embodiment, each of the projections 25 has a shape in which the projection side surface 253 gradually approaches the center CL of the projection 25 from the frame connection portion 251 side toward the abutment portion 252 side. This makes it possible to reduce the contact area between the abutting portion 252 of the projection 25 and the working electrode 21, and increase the area of ​​the working electrode 21 exposed to the gas flow passage 30, that is, the area for adsorbing CO2. Furthermore, even if the center position of the protrusion 25 of a given cell 20 is slightly misaligned from the center position of the protrusion 25 of another cell 20 in the stacking direction, the abutting portion 252 of the protrusion 25 of the given cell 20 is prevented from being misaligned outwardly from the frame connecting portion 251 of the protrusion 25 of the other cell 20 as viewed in the stacking direction. This prevents stress from concentrating on only a portion of the protrusion 25 due to a load applied to the multiple cells 20 in the stacking direction, thereby preventing the protrusion 25 from buckling. This prevents the gas flow path 30 from narrowing.

[0066] (10) In the first embodiment, the end 254 of each protrusion 25 on the contact portion 252 side is curved. This makes it possible to reduce the contact area between the abutting portion 252 of the projection 25 and the working electrode 21, and increase the area of ​​the working electrode 21 exposed to the gas flow passage 30, that is, the area for adsorbing CO2. Even if the positions of the multiple protrusions 25 arranged linearly in the stacking direction are slightly misaligned, stress concentration on only a portion of the protrusions 25 due to a load applied to the multiple cells 20 in the stacking direction is prevented, and buckling of the protrusions 25 is prevented. Therefore, narrowing of the gas flow path 30 can be prevented.

[0067] (11) In the first embodiment, the lid portion 12 of the housing 10 is fixed to the support pillars 13 in a state in which a load is applied to the multiple cells 20 in the stacking direction. According to this, with a simple configuration, the plurality of cells 20 can be housed in the housing 10 in a state in which a load is applied to the plurality of cells 20 in the stacking direction.

[0068] (12) In the first embodiment, the bottom 11 of the housing 10 has a surface with which the lowermost cell 20 of the stacked cells 20 comes into contact, the surface having a plurality of holes 14 into which the plurality of protrusions 25 are inserted. This allows the frame 24 of the lowest cell 20 to abut against the bottom 11 of the housing 10, eliminating unnecessary space and allowing more cells 20 to be provided in the housing 10 by that amount. Therefore, the CO2 recovery device 1 can improve the CO2 recovery efficiency.

[0069] (Second to Ninth Embodiments) The second to ninth embodiments are different from the first embodiment in the shape and arrangement of the protrusions 25, but are otherwise similar to the first embodiment, so only the parts that differ from the first embodiment will be described.

[0070] Second embodiment A second embodiment will be described. As shown in Fig. 12 and Fig. 13, the protrusion 25a in the second embodiment has a shape in which a semicircle is combined with both ends in the longitudinal direction of a rectangle when viewed in the normal direction of the bottom plate 26 of the frame 24, i.e., the stacking direction. In other words, the protrusion 25a in the second embodiment has a shape in which the short side of a rectangle is made into an arc shape.

[0071] As shown in FIG. 13, the plurality of protrusions 25a are arranged in a lattice on the bottom plate 26 of the frame 24. The plurality of protrusions 25a are arranged in a plurality of rows in the second direction. Hereinafter, for convenience of explanation, the rows of the protrusions 25a arranged in the second direction are called the first row, the second row, the third row, etc., in order from the gas inlet 15 side. The long sides of the individual protrusions 25a are arranged diagonally with respect to the first direction. In addition, the individual protrusions 25a are arranged at different angles for each row. Specifically, the direction of the long sides of the protrusions 25a constituting the first row, the third row, and the fifth row (i.e., the odd-numbered rows) is different from the direction of the long sides of the protrusions 25a constituting the second row, the fourth row, and the sixth row (i.e., the even-numbered rows). The direction of the long sides of the protrusions 25a constituting the first row, the third row, and the fifth row (i.e., the odd-numbered rows) is the same. Moreover, the long sides of the projections 25a constituting the second, fourth and sixth rows (that is, the even-numbered rows) are oriented in the same direction.

[0072] The second embodiment described above can also achieve the same effects as the first embodiment.

[0073] Third embodiment A third embodiment will now be described. As shown in Fig. 14, the shape of the protrusion 25a in the third embodiment is the same as that described in the second embodiment.

[0074] The plurality of protrusions 25a are arranged in a plurality of rows in the second direction. In the third embodiment, the plurality of protrusions 25a are arranged with a different pitch in the second direction for each row. Specifically, the pitch in the second direction of the plurality of protrusions 25a constituting the first row, the pitch in the second direction of the plurality of protrusions 25a constituting the second row, and the pitch in the second direction of the plurality of protrusions 25a constituting the third row are different. The pitch in the second direction of the plurality of protrusions 25a constituting the first row is the same as the pitch in the second direction of the plurality of protrusions 25a constituting the sixth row. The pitch in the second direction of the plurality of protrusions 25a constituting the second row is the same as the pitch in the second direction of the plurality of protrusions 25a constituting the fifth row. The pitch in the second direction of the plurality of protrusions 25a constituting the third row is the same as the pitch in the second direction of the plurality of protrusions 25a constituting the fourth row. The above-described third embodiment can also achieve the same effects as the first embodiment.

[0075] (Fourth embodiment) A fourth embodiment will be described below. As shown in Figures 15 and 16, a protrusion 25b in the fourth embodiment has a rhombus with rounded corners when viewed in the normal direction of the bottom plate 26 of the frame 24, that is, the stacking direction.

[0076] 15, the multiple protrusions 25b are arranged in a lattice pattern. In other words, the multiple protrusions 25b are lined up in the first direction and also lined up in the second direction. The fourth embodiment described above can also achieve the same effects as the first embodiment.

[0077] Fifth embodiment A fifth embodiment will be described below. As shown in Fig. 17, the shape of the protrusion 25b in the fifth embodiment is the same as that described in the fourth embodiment.

[0078] The multiple protrusions 25b are arranged in a staggered pattern. Specifically, the protrusions 25b constituting the second row are arranged between the protrusions 25b constituting the first row. Furthermore, the protrusions 25b constituting the third row are arranged between the protrusions 25b constituting the second row. The fourth row and beyond are arranged in the same manner.

[0079] Moreover, each of the multiple protrusions 25b is arranged such that the longer diagonal of the rhombus is oblique to the first direction. Furthermore, the multiple protrusions 25b are arranged at different angles for each row. Specifically, the direction of the longer diagonal of the rhombus in the multiple protrusions 25b constituting the odd-numbered rows is different from the direction of the longer diagonal of the rhombus in the multiple protrusions 25b constituting the even-numbered rows. Furthermore, the direction of the longer diagonal of the rhombus in the multiple protrusions 25b constituting the odd-numbered rows is the same. Furthermore, the direction of the longer diagonal of the rhombus in the multiple protrusions 25b constituting the even-numbered rows is the same. The fifth embodiment described above can also achieve the same effects as the first embodiment.

[0080] Sixth embodiment A sixth embodiment will be described. As shown in Fig. 18 and Fig. 19, the protrusion 25c of the sixth embodiment has a shape in which one side of a rectangle overlaps one side of a triangle when viewed in the normal direction of the bottom plate 26 of the frame 24, i.e., the stacking direction, and further, the corner of the triangle opposite to the rectangle is rounded.

[0081] As shown in Fig. 19, the multiple protrusions 25c are arranged in a lattice pattern. In other words, the multiple protrusions 25c are lined up in the first direction and also lined up in the second direction. The multiple protrusions 25c lined up in the second direction are alternately arranged with a shape in which a triangle is located on one side of a square in the first direction and a shape in which a triangle is located on the other side of a square in the first direction. The multiple protrusions 25c lined up in the first direction are also alternately arranged with a shape in which a triangle is located on one side of a square in the first direction and a shape in which a triangle is located on the other side of a square in the first direction. The sixth embodiment described above can also achieve the same effects as the first embodiment.

[0082] Seventh embodiment A seventh embodiment will be described. As shown in Fig. 20 and Fig. 21, a protrusion 25d in the seventh embodiment has a circular shape when viewed in the normal direction of the bottom plate 26 of the frame 24, that is, the stacking direction. That is, the multiple protrusions 25d are cylindrical.

[0083] 21, the multiple protrusions 25d are arranged in a lattice pattern. In other words, the multiple protrusions 25d are lined up in the first direction and also lined up in the second direction. The seventh embodiment described above can also achieve the same effects as the first embodiment.

[0084] Eighth embodiment An eighth embodiment will now be described. As shown in Fig. 22, the shape of a protrusion 25d in the eighth embodiment is the same as that described in the seventh embodiment.

[0085] The multiple protrusions 25d are arranged in a staggered pattern. Specifically, the protrusions 25d constituting the second row are arranged between the protrusions 25d constituting the first row. Furthermore, the protrusions 25d constituting the third row are arranged between the protrusions 25d constituting the second row. The fourth row and subsequent rows are arranged in the same manner. The eighth embodiment described above can also achieve the same effects as the first embodiment.

[0086] Ninth embodiment A ninth embodiment will now be described. As shown in Fig. 23, the shape of a protrusion 25d in the ninth embodiment is also the same as that described in the seventh embodiment.

[0087] The multiple protrusions 25d are arranged concentrically about a predetermined position on the bottom plate 26 of the frame 24. The ninth embodiment described above can also achieve the same effects as the first embodiment.

[0088] (Other embodiments) (1) In each of the above embodiments, one example of the shape and arrangement of the protrusion 25 is shown, but the shape and arrangement of the protrusion 25 are not limited to these examples, and the shape and arrangement of the protrusion 25 can be any combination of the examples of each embodiment, and further, any other shape and arrangement can be used.

[0089] (2) In each of the above embodiments, the CO2 capture apparatus 1 has been described as being used in the CO2 capture system 2. However, the CO2 capture apparatus 1 may be used for any purpose.

[0090] (3) In each of the above embodiments, the housing 10 of the CO2 recovery device 1 has been described as having a rectangular parallelepiped shape having a bottom 11, a lid 12, and four pillars 13, but this is not limited to the above and the housing 10 can have any shape and configuration.

[0091] (4) In each of the above embodiments, the working electrode 21 is coated with a CO2 adsorbent. However, the present invention is not limited to this. The working electrode 21 may not be coated with a CO2 adsorbent.

[0092] The present disclosure is not limited to the above-mentioned embodiments, and can be appropriately modified within the scope of the claims. In addition, the above-mentioned embodiments and parts thereof are not unrelated to each other, and can be appropriately combined except when the combination is clearly impossible. In addition, in each of the above-mentioned embodiments, it goes without saying that the elements constituting the embodiment are not necessarily essential, except when it is specifically stated that they are essential or when it is clearly considered to be essential in principle. In addition, in each of the above-mentioned embodiments, when the numbers, values, amounts, ranges, etc. of the components of the embodiment are mentioned, they are not limited to the specific numbers, except when it is specifically stated that they are essential or when it is clearly limited to a specific number in principle. In addition, in each of the above-mentioned embodiments, when the shape, positional relationship, etc. of the components are mentioned, they are not limited to the shape, positional relationship, etc., except when it is specifically stated that they are essential or when it is clearly limited to a specific shape, positional relationship, etc. in principle.

[0093] (In view of the present disclosure) The present disclosure described above can be understood from the following viewpoints, for example. [First viewpoint] A carbon dioxide recovery apparatus for recovering carbon dioxide from a carbon dioxide-containing gas, a housing (10) having a gas inlet (15) and a gas outlet (16); a plurality of plate-shaped electrochemical cells (20) stacked inside the housing; The electrochemical cell comprises: A working electrode (21) as one electrode for adsorbing carbon dioxide; a counter electrode (22) as the other electrode containing an electroactive auxiliary material; a separator (23) provided between the working electrode and the counter electrode; a frame (24) on which the working electrode, the counter electrode, and the separator are placed; a plurality of protrusions (25) provided on a surface of the frame opposite to a surface on which the working electrode, the counter electrode, and the separator are placed; The electrochemical cells are housed in the housing with a load applied in a stacking direction (LD), a carbon dioxide recovery device, wherein the plurality of protrusions provided on the frame of a predetermined electrochemical cell abut against the working electrode of another electrochemical cell adjacent to the predetermined electrochemical cell in the stacking direction, and a gas flow path (30) through which the carbon dioxide-containing gas flows is formed between the frame of the predetermined electrochemical cell and the working electrode of the other electrochemical cell. [Second viewpoint] The carbon dioxide capture apparatus according to a first aspect, wherein the protrusions of each of the stacked electrochemical cells are arranged linearly in a stacking direction. [Third Perspective] The carbon dioxide recovery device described in the first or second aspect, wherein the spacing (P1, P2) between adjacent protrusions on the frame is set so that a surface pressure per unit area applied to the electrochemical cell is uniform. [Fourth viewpoint] The carbon dioxide recovery device according to any one of the first to third aspects, wherein the distance between adjacent protrusions on the frame is set so that the surface pressure of an intermediate portion (202) between adjacent protrusions in the electrochemical cell is 70% or more of the surface pressure of a portion (201) in the electrochemical cell where the protrusions are provided. [Fifth viewpoint] A direction connecting the center of the gas inlet and the center of the gas outlet is referred to as a first direction (D1), and a direction perpendicular to the first direction and perpendicular to the stacking direction is referred to as a second direction (D2). The carbon dioxide capture device according to any one of the first to fourth aspects, wherein the plurality of protrusions are arranged at intervals in the second direction so as to form a linear flow path (AF) in the first direction. [Sixth viewpoint] The carbon dioxide capture device according to a fifth aspect, wherein the plurality of protrusions have a length (L1) in the first direction longer than a length (L2) in the second direction when viewed in the stacking direction. [Seventh viewpoint] The carbon dioxide capture device according to any one of the first to sixth aspects, wherein the plurality of protrusions have a circular, elliptical, or polygonal shape, or a combination thereof, in a cross-sectional view perpendicular to the stacking direction. [Eighth viewpoint] The carbon dioxide capture apparatus according to any one of the first to seventh aspects, wherein the plurality of protrusions are arranged in a lattice pattern, a concentric circle pattern, or a staggered pattern. [Ninth viewpoint] In each of the projections, a portion connected to the frame is called a frame connection portion (251), a portion abutting against the working electrode is called a contact portion (252), and a surface connecting the frame connection portion and the contact portion is called a projection side surface (253). A carbon dioxide capture device as described in any one of the first to eighth aspects, wherein each of the protrusions has a shape in which the protrusion side surface gradually approaches the center (CL) of the protrusion from the frame connection portion side toward the abutment portion side. [10th viewpoint] The carbon dioxide capture device according to a ninth aspect, wherein an end (254) of each of the projections on the contact portion side is curved. [Eleventh viewpoint] The housing has a bottom (11) on which a plurality of the electrochemical cells are placed in a stacked state, a lid (12) facing the bottom with the plurality of the electrochemical cells interposed therebetween, and a support (13) connecting the bottom and the lid, The carbon dioxide capture apparatus according to any one of the first to tenth aspects, wherein the lid portion is fixed to the support in a state in which a load is applied to the plurality of electrochemical cells in a stacking direction. [12th viewpoint] The carbon dioxide recovery apparatus according to an eleventh aspect, wherein the bottom portion has a plurality of holes (14) into which the plurality of protrusions fit, on a surface that contacts a lowest one of the plurality of stacked electrochemical cells. [Explanation of symbols]

[0094] 10. Chassis 15 Gas inlet 16 Gas outlet 20 Electrochemical Cell 21 Working electrode 22 Opposite 23 Separator 24 Frames 25 Protrusion 30 Gas flow path

Claims

1. A carbon dioxide recovery apparatus for recovering carbon dioxide from a carbon dioxide-containing gas, A housing (10) having a gas inlet (15) and a gas outlet (16); and a plurality of plate-shaped electrochemical cells (20) stacked inside the housing, The electrochemical cell comprises: A working electrode (21) as one electrode for adsorbing carbon dioxide; A counter electrode (22) as the other electrode containing an electroactive auxiliary material; A separator (23) provided between the working electrode and the counter electrode; A frame (24) on which the working electrode, the counter electrode, and the separator are placed; a plurality of protrusions (25) provided on a surface of the frame opposite to a surface on which the working electrode, the counter electrode, and the separator are placed; The electrochemical cells are housed in the housing with a load applied in a stacking direction (LD), a carbon dioxide recovery device, wherein a plurality of the protrusions provided on the frame of a predetermined electrochemical cell abut against the working electrode of another electrochemical cell adjacent to the predetermined electrochemical cell in the stacking direction, and a gas flow path (30) through which the carbon dioxide-containing gas flows is formed between the frame of the predetermined electrochemical cell and the working electrode of the other electrochemical cell.

2. The carbon dioxide capture device according to claim 1 , wherein the plurality of protrusions of each of the plurality of stacked electrochemical cells are arranged linearly in a stacking direction.

3. 3. The carbon dioxide recovery device according to claim 1, wherein the intervals (P1, P2) between adjacent protrusions on the frame are set so that a predetermined surface pressure per unit area applied to the electrochemical cell is uniform.

4. 3. The carbon dioxide recovery device according to claim 1, wherein the distance between adjacent protrusions on the frame is set so that the surface pressure of an intermediate portion (202) between adjacent protrusions in the electrochemical cell is 70% or more of the surface pressure of a portion (201) in the electrochemical cell where the protrusions are provided.

5. A direction connecting the center of the gas inlet and the center of the gas outlet is referred to as a first direction (D1), and a direction perpendicular to the first direction and perpendicular to the stacking direction is referred to as a second direction (D2). The carbon dioxide capture device according to claim 1 or 2, wherein the plurality of protrusions are arranged at intervals in the second direction so as to form a linear flow path (AF) in the first direction.

6. The carbon dioxide capture device according to claim 5 , wherein the plurality of protrusions have a length (L1) in the first direction longer than a length (L2) in the second direction when viewed from the stacking direction.

7. The carbon dioxide capture device according to claim 1 or 2, wherein the plurality of protrusions have a circular, elliptical, polygonal or combination thereof in a cross section perpendicular to the stacking direction.

8. The carbon dioxide capture device according to claim 1 or 2, wherein the plurality of protrusions are arranged in a lattice pattern, a concentric circle pattern, or a staggered pattern.

9. In each of the projections, a portion connected to the frame is called a frame connection portion (251), a portion abutting against the working electrode is called a contact portion (252), and a surface connecting the frame connection portion and the contact portion is called a projection side surface (253).

3. The carbon dioxide capture device according to claim 1, wherein each of the projections has a shape in which the projection side surface gradually approaches a center (CL) of the projection from the frame connection portion side toward the abutment portion side.

10. The carbon dioxide capture device according to claim 9 , wherein an end (254) of each of the projections on the contact portion side is curved.

11. The housing has a bottom (11) on which a plurality of the electrochemical cells are placed in a stacked state, a lid (12) facing the bottom with the plurality of the electrochemical cells interposed therebetween, and a support (13) connecting the bottom and the lid, The carbon dioxide capture device according to claim 1 , wherein the lid portion is fixed to the support pillar in a state in which a load is applied to the electrochemical cells in a stacking direction.

12. The carbon dioxide recovery device according to claim 11, wherein the bottom portion has a plurality of holes (14) into which the plurality of protrusions fit, on a surface that contacts the lowest one of the plurality of stacked electrochemical cells.

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