Gas recovery system

Abstract

To provide a gas recovery system that can be prevented from deteriorating in capability of recovering gas to be recovered.SOLUTION: A carbon dioxide recovery system 1 recovers gas to be recovered from mixed gas by electrochemical reaction, and is provided with an electrochemical cell 101 and counter electrode surrounding members 110. The electrochemical cell 101 is constituted of a working electrode 104, a counter electrode 106, a separator 107, a working electrode power-collecting material 103 and a counter electrode power-collecting material 105 which are laminatedly arranged. The working electrode 104 adsorbs the gas to be recovered. The counter electrode 106 gives and receives electrons with the counter electrode 104. The counter electrode surrounding members 110 are arranged to cover the counter electrode 106 and the counter electrode power-collecting material 105 with respect to the electrochemical cell 101, which prevents the mixed gas from contacting the counter electrode 106.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a gas recovery system for recovering a recovery target gas from a mixed gas containing the recovery target gas. [Background Art]

[0002] Conventionally, Patent Document 1 discloses a carbon dioxide recovery system that recovers carbon dioxide, which is a recovery target gas, from a mixed gas containing carbon dioxide. The carbon dioxide recovery system of Patent Document 1 includes an electrochemical cell that adsorbs carbon dioxide through an electrochemical reaction.

[0003] The electrochemical cell is formed as a laminate in which a working electrode, a counter electrode, a working electrode current collector, a counter electrode current collector and the like, each formed in a flat plate shape, are laminated. The working electrode contains a carbon dioxide adsorbent that absorbs carbon dioxide from the mixed gas. The counter electrode contains an electroactive auxiliary material that exchanges electrons with the working electrode. The working electrode current collector is an electrode in contact with the working electrode. The counter electrode current collector is an electrode in contact with the counter electrode. [Prior Art Documents] [Patent Documents]

[0004] [Patent Document 1] Japanese National Publication of International Patent Application No. 2018-533470 [Summary of the Invention] [Problem to be Solved by the Invention]

[0005] Here, in a carbon dioxide recovery system, it is necessary to expose the working electrode to the mixed gas in order to cause the carbon dioxide adsorbent of the working electrode to adsorb carbon dioxide. Therefore, in Patent Document 1, the working electrode current collector is formed of a gas permeable membrane.

[0006] On the other hand, if the counter electrode is exposed to the mixed gas, the electroactivating auxiliary material of the counter electrode may be oxidized by the potential applied to the counter electrode. If the electroactivating auxiliary material is oxidized, it is possible that the recovery capacity of the target gas in the gas recovery system will decrease.

[0007] In view of the above points, this disclosure aims to provide a gas recovery system that can suppress the decrease in the recovery capacity of the gas to be recovered. [Means for solving the problem]

[0008] A gas recovery system according to one aspect of this disclosure is a gas recovery system that recovers a target gas from a mixed gas by an electrochemical reaction, and comprises an electrochemical cell (101) and a counter electrode surrounding member (110).

[0009] The electrochemical cell is constructed by stacking a working electrode (104), a counter electrode (106), a separator (107), a working electrode current collector (103), and a counter electrode current collector (105). The working electrode adsorbs the gas to be recovered. The counter electrode exchanges electrons with the working electrode. The separator is placed between the working electrode and the counter electrode to prevent physical contact between them and suppress electrical short circuits. The working electrode current collector contacts the working electrode to electrically connect the working electrode and the counter electrode. The counter electrode current collector contacts the counter electrode to electrically connect the working electrode and the counter electrode. The counter electrode surrounding member is positioned to cover the counter electrode and the counter electrode current collector with respect to the electrochemical cell, suppressing contact between the mixed gas and the counter electrode. The counter electrode surrounding member is made of a film member formed of a material that is impermeable to the mixed gas. Multiple holes are formed on the outer edge of the separator, penetrating the separator. The film member is positioned to cover the counter electrode and the counter electrode current collector, and at least the outer edge of the separator. via the outside, sandwiching the outer edge of the separator In this state, the parts are joined together inside multiple holes.

[0010] In the gas recovery system, contact between the mixed gas and the counter electrode is suppressed by a counter electrode surround member positioned relative to the electrochemical cell. As a result, the gas recovery system can suppress oxidation of the counter electrode and prevent a decrease in the recovery capacity of the target gas in the gas recovery system.

[0011] The reference numerals in parentheses next to each means described in this section and in the claims indicate the correspondence with the specific means described in the embodiments described later. [Brief explanation of the drawing]

[0012] [Figure 1] This is a conceptual diagram showing the overall configuration of the carbon dioxide capture system according to the first embodiment. [Figure 2] This is an explanatory diagram showing the configuration of a carbon dioxide capture device. [Figure 3] This is an explanatory diagram showing the configuration of an electrochemical cell in a carbon dioxide capture device. [Figure 4] This is an exploded perspective view of the electrochemical cell according to the first embodiment. [Figure 5] This is a cross-sectional view showing the configuration of an electrochemical cell according to the first embodiment. [Figure 6] This is a cross-sectional view showing the configuration of an electrochemical cell according to the second embodiment. [Figure 7] This is an exploded perspective view of the electrochemical cell according to the third embodiment. [Figure 8] This is a cross-sectional view showing the configuration of an electrochemical cell according to the third embodiment. [Figure 9] This is a cross-sectional view showing the configuration of an electrochemical cell according to the fourth embodiment. [Figure 10] This is a cross-sectional view showing the configuration of an electrochemical cell according to the fifth embodiment. [Modes for carrying out the invention]

[0013] Hereinafter, a plurality of modes for carrying out the present disclosure will be described with reference to the drawings. In each embodiment, portions corresponding to the matters described in the preceding embodiments may be denoted by the same reference numerals, and overlapping descriptions may be omitted. When only a part of the configuration is described in each embodiment, the other embodiments described above can be applied to the other parts of the configuration. Not only combinations of parts that are explicitly stated to be combinable in each embodiment, but also partial combinations of embodiments even if not explicitly stated, are possible as long as there is no obstacle to the combination.

[0014] (First Embodiment) A first embodiment of the present disclosure will be described with reference to the drawings. The first embodiment applies the gas recovery system of the present disclosure to a carbon dioxide recovery system 1 that separates and recovers carbon dioxide from a mixed gas containing carbon dioxide. Accordingly, the recovery target gas of the present embodiment is carbon dioxide.

[0015] As shown in FIG. 1, a carbon dioxide recovery system 1 according to the first embodiment includes a carbon dioxide recovery device 10, a pump 11, a flow path switching valve 12, a carbon dioxide utilization device 13, and a control device 14.

[0016] The carbon dioxide recovery device 10 separates and recovers carbon dioxide from the mixed gas. As the mixed gas, atmospheric air or exhaust gas from an internal combustion engine can be used. The mixed gas also contains gases other than carbon dioxide. The mixed gas is supplied to the carbon dioxide recovery device 10. The carbon dioxide recovery device 10 discharges the mixed gas after carbon dioxide has been removed, or the recovered carbon dioxide. A detailed configuration of the carbon dioxide recovery device 10 will be described later.

[0017] An inlet side of the pump 11 is connected to an outlet of the carbon dioxide recovery device 10. The pump 11 sucks the mixed gas after carbon dioxide has been removed, or the recovered carbon dioxide, from the carbon dioxide recovery device 10. Further, the mixed gas is supplied to the carbon dioxide recovery device 10 by the suction action of the pump 11.

[0018] Furthermore, although the present embodiment describes an example where the pump 11 is arranged on the downstream side of the carbon dioxide capture device 10 in the gas flow direction, the pump 11 may be arranged on the upstream side of the carbon dioxide capture device 10 in the gas flow direction.

[0019] The inlet side of the flow path switching valve 12 is connected to the discharge port of the pump 11. The flow path switching valve 12 is a three-way valve that switches the flow path of gas flowing out from the carbon dioxide capture device 10. One of the outlets of the flow path switching valve 12 is connected to the atmosphere side, and the other outlet of the flow path switching valve 12 is connected to the carbon dioxide utilization device 13 side. Accordingly, the flow path switching valve 12 switches between a flow path that causes the gas flowing out from the carbon dioxide capture device 10 to flow out to the atmosphere side, and a flow path that causes the gas flowing out from the carbon dioxide capture device 10 to flow out to the carbon dioxide utilization device 13 side.

[0020] The carbon dioxide utilization device 13 is a device that utilizes carbon dioxide. As the carbon dioxide utilization device 13, for example, a storage tank that stores carbon dioxide or a conversion device that converts carbon dioxide into fuel can be used. The conversion device is a device that converts carbon dioxide into a hydrocarbon fuel such as methane. The hydrocarbon fuel may be a gaseous fuel at normal temperature and normal pressure, or may be a liquid fuel at normal temperature and normal pressure.

[0021] The control device 14 is constituted by a well-known microcomputer including a CPU, ROM, RAM and the like, and peripheral circuits thereof. The control device 14 performs various calculations and processes based on a control program stored in the ROM, and controls the operation of various control target devices connected to the output side. More specifically, the control device 14 of the present embodiment controls the operation of the carbon dioxide capture device 10, the pump 11, and the flow path switching valve 12.

[0022] Next, the configuration of the carbon dioxide capture device 10 used in the carbon dioxide capture system 1 will be described with reference to FIGS. 2 and 3. As shown in FIG. 2, the carbon dioxide capture device 10 includes a housing 100 and a plurality of electrochemical cells 101. The housing 100 of the present embodiment is formed of a metal material. The housing 100 may be formed of a resin material.

[0023] The housing 100 has a gas inlet and a gas outlet. The gas inlet is an opening for introducing the mixed gas into the housing 100. The gas outlet is an opening for releasing the mixed gas, after carbon dioxide has been removed, or the recovered carbon dioxide, from inside the housing 100.

[0024] The electrochemical cell 101 adsorbs carbon dioxide through an electrochemical reaction, separating and recovering it from the mixed gas. The electrochemical cell 101 also releases the adsorbed carbon dioxide through an electrochemical reaction. Multiple electrochemical cells 101 are housed in the enclosure 100.

[0025] The electrochemical cell 101 is formed in the shape of a rectangular flat plate. Multiple electrochemical cells 101 are stacked inside the housing 100 at regular intervals so that their plate surfaces are parallel to each other.

[0026] Multiple gas channels 102 are formed between adjacent electrochemical cells 101 to allow the mixed gas flowing in from the gas inlet to circulate. Therefore, the flow direction of the mixed gas is parallel to the plate surface of the electrochemical cell 101 and perpendicular to the stacking direction of the multiple electrochemical cells 101.

[0027] As shown in Figure 3, the electrochemical cell 101 includes a working electrode current collector 103, a working electrode 104, a counter electrode current collector 105, a counter electrode 106, a separator 107, and an electrolyte layer 108. The working electrode current collector 103, the working electrode 104, the counter electrode current collector 105, the counter electrode 106, and the separator 107 are all formed in the shape of rectangular flat plates.

[0028] The electrochemical cell 101 is formed as a laminate of a working electrode current collector 103, a working electrode 104, a counter electrode current collector 105, a counter electrode 106, and a separator 107. The lamination direction in which the working electrode current collector 103, etc., are stacked in each individual electrochemical cell 101 coincides with the lamination direction in which multiple electrochemical cells 101 are stacked inside the housing 100.

[0029] The working electrode current collector 103 is a conductive member that contacts the working electrode 104 and electrically connects the working electrode 104 and the counter electrode 106. As shown in Figure 4, the working electrode current collector 103 has a working electrode side lead-out portion 103a, which is connected to the power supply 109.

[0030] Furthermore, one flat surface of the working electrode current collector 103 is exposed to the mixed gas. The other flat surface of the working electrode current collector 103 is in contact with the working electrode 104. Multiple working electrode openings 103b are formed in the working electrode current collector 103 to expose the mixed gas on one flat surface side to the working electrode 104 on the other flat surface side.

[0031] Specifically, the working electrode current collector 103 in this embodiment is made of a porous metal. Therefore, the working electrode opening 103b in this embodiment is formed by multiple voids formed inside the working electrode current collector 103 communicating with each other. As the working electrode current collector 103, a porous metal with a porosity of 50% or more can be used. The porosity is defined as the ratio of the volume of voids to the apparent volume.

[0032] The working electrode 104 can adsorb and recover carbon dioxide from a mixed gas, and desorb and release the recovered carbon dioxide. The working electrode 104 comprises a carbon dioxide adsorbent, a conductive additive, and a binder. The carbon dioxide adsorbent, conductive additive, and binder are used in a mixture state. More specifically, the carbon dioxide adsorbent and the conductive additive are used in a state in which they are held by the binder.

[0033] Carbon dioxide adsorbents are electroactive species that adsorb carbon dioxide by accepting electrons and desorb the adsorbed carbon dioxide by releasing electrons. For example, polyanthraquinone can be used as a carbon dioxide adsorbent.

[0034] The conductive additive forms a conductive path to the carbon dioxide adsorbent. Examples of conductive additives include carbon materials such as carbon nanotubes, carbon black, and graphene.

[0035] The binder is a binder that holds the carbon dioxide adsorbent and the conductive additive. As the binder, for example, a conductive resin made of a high-molecular-weight polymer can be used. As the conductive resin, an organic material such as epoxy resin containing Ag or the like as a conductive filler, or fluororesin such as polytetrafluoroethylene (PTFE) or polyvinylidene fluoride (PVDF) can be used.

[0036] The counter electrode current collector 105 is a conductive member that contacts the counter electrode 106 and electrically connects the working electrode 104 and the counter electrode 106. As shown in Figure 4, the counter electrode current collector 105 has a counter electrode side lead portion 105a formed thereon, which is connected to the power supply 109. One flat surface of the counter electrode current collector 105 is exposed to the mixed gas. The other flat surface of the counter electrode current collector 105 is in contact with the counter electrode 106.

[0037] The counter electrode 106 exchanges electrons with the working electrode 104 when the carbon dioxide adsorbent adsorbs or desorbs carbon dioxide. The counter electrode 106 comprises an electroactivating agent, a conductive additive, and a binder. The electroactivating agent, conductive additive, and binder are used in a mixture state. More specifically, in this embodiment, fine particles of the electroactivating agent and fine particles of the conductive additive are used in a state held by the binder.

[0038] The basic composition of the conductive additive and binder of the counter electrode 106 is the same as that of the conductive additive and binder of the working electrode 104. The electroactivating additive is an auxiliary electroactive species that transfers electrons with the carbon dioxide adsorbent of the working electrode 104, and is an active material with redox properties. As the active material, an organic compound having a π bond, a transition metal compound that can take on multiple oxidation states, or a metal complex that enables electron transfer by changing the valence of a metal ion can be used.

[0039] Examples of such metal complexes include cyclopentadienyl metal complexes such as ferrocene, nickerosene, and cobaltocene, or porphyrin metal complexes. These metal complexes may be polymers or monomers.

[0040] The separator 107 is positioned between the working electrode 104 and the counter electrode 106, separating them. The separator 107 is an insulating ion-permeable membrane that prevents physical contact between the working electrode 104 and the counter electrode 106, thereby suppressing electrical short circuits, while also allowing ions to pass through. As the separator 107, a cellulose membrane, a polymer, a composite material of polymer and ceramic, etc., can be used.

[0041] The electrolyte layer 108 is an immersion layer in which the working electrode 104, separator 107, and counter electrode 106 are immersed. For example, an ionic liquid can be used as the electrolyte layer 108. An ionic liquid is a salt of a liquid that is non-volatile at room temperature and pressure.

[0042] Furthermore, a power supply 109 is connected to the working electrode current collector 103 and the counter electrode current collector 105 of the electrochemical cell 101. The power supply 109 can apply a predetermined voltage to the working electrode 104 and the counter electrode 106, thereby changing the potential difference between the working electrode 104 and the counter electrode 106. The working electrode 104 is the negative electrode, and the counter electrode 106 is the positive electrode.

[0043] The electrochemical cell 101 operates in a carbon dioxide capture mode, in which carbon dioxide is captured at the working electrode 104, and in a carbon dioxide release mode, in which carbon dioxide is released from the working electrode 104, by changing the potential difference between the working electrode 104 and the counter electrode 106. The carbon dioxide capture mode is a charging mode that charges the electrochemical cell 101, and the carbon dioxide release mode is a discharge mode that discharges the electrochemical cell 101.

[0044] Specifically, in carbon dioxide capture mode, a first voltage V1 is applied between the working electrode 104 and the counter electrode 106, and electrons are supplied from the counter electrode 106 to the working electrode 104. At the first voltage V1, the working electrode potential is less than the counter electrode potential. The first voltage V1 can be, for example, in the range of 0.5 to 2.0 V.

[0045] In the carbon dioxide emission mode, a second voltage V2 is applied between the working electrode 104 and the counter electrode 106, supplying electrons from the working electrode 104 to the counter electrode 106. The second voltage V2 is different from the first voltage V1. The second voltage V2 only needs to be lower than the first voltage V1, and the relative magnitudes of the working electrode potential and the counter electrode potential are not limited. In other words, in the carbon dioxide emission 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.

[0046] Next, the operation of the carbon dioxide capture system 1 will be explained. As described above, the carbon dioxide capture system 1 operates by alternately switching between carbon dioxide capture mode and carbon dioxide release mode. The operation of the carbon dioxide capture system 1 is controlled by the control device 14.

[0047] First, the operation of the carbon dioxide recovery system 1 in carbon dioxide recovery mode will be explained. In carbon dioxide recovery mode, the pump 11 is activated. This supplies the mixed gas to the carbon dioxide recovery device 10. In the carbon dioxide recovery device 10, the voltage applied between the working electrode 104 and the counter electrode 106 of the electrochemical cell 101 is defined as the first voltage V1. This allows for the simultaneous donation of electrons to the electroactivating auxiliary material of the counter electrode 106 and the withdrawal of electrons to the carbon dioxide adsorbent of the working electrode 104.

[0048] The carbon dioxide adsorbent on the working electrode 104, having received electrons from the counter electrode 106, has increased carbon dioxide binding affinity and adsorbs carbon dioxide contained in the mixed gas. As a result, the carbon dioxide recovery device 10 can recover carbon dioxide from the mixed gas. The mixed gas, after carbon dioxide has been removed, is discharged from the carbon dioxide recovery device 10.

[0049] In carbon dioxide recovery mode, the flow path switching valve 12 switches to a flow path that allows the mixed gas discharged from the carbon dioxide recovery device 10 to flow out to the atmosphere. As a result, the mixed gas discharged from the carbon dioxide recovery device 10 is released into the atmosphere.

[0050] Next, the operation of the carbon dioxide recovery system 1 in carbon dioxide release mode will be described. In carbon dioxide release mode, the pump 11 is stopped. This stops the supply of mixed gas to the carbon dioxide recovery device 10. In the carbon dioxide recovery device 10, the voltage applied between the working electrode 104 and the counter electrode 106 of the electrochemical cell 101 is set to the second voltage V2. This allows for simultaneous electron donation to the carbon dioxide adsorbent of the working electrode 104 and electron withdrawal to the electroactivating auxiliary material of the counter electrode 106.

[0051] The carbon dioxide adsorbent at the working electrode 104 releases electrons and enters an oxidized state. The carbon dioxide adsorbent's binding force to carbon dioxide decreases, and it desorbs and releases carbon dioxide. The carbon dioxide released from the carbon dioxide adsorbent is discharged from the carbon dioxide recovery device 10.

[0052] In carbon dioxide release mode, the flow path switching valve 12 switches to a flow path that allows carbon dioxide emitted from the carbon dioxide recovery device 10 to flow out to the inlet side of the carbon dioxide utilization device 13. As a result, the carbon dioxide emitted from the carbon dioxide recovery device 10 is supplied to the carbon dioxide utilization device 13.

[0053] As described above, the carbon dioxide recovery system 1 of this embodiment allows for the recovery of carbon dioxide from a mixed gas and the effective utilization of the recovered carbon dioxide.

[0054] Next, the manufacturing method for the electrochemical cell 101 described above will be explained. The manufacturing method for the electrochemical cell 101 in this embodiment includes a working electrode side current collector attachment step in which the working electrode 104 is attached to the working electrode current collector 103, and a counter electrode side current collector attachment step in which the counter electrode 106 is attached to the counter electrode current collector 105. The working electrode side current collector attachment step and the counter electrode side current collector attachment step can be carried out separately.

[0055] The process of attaching the current collector to the working electrode and the process of attaching the current collector to the counter electrode are basically the same. Therefore, we will first explain the process of attaching the current collector to the working electrode. In the process of attaching the current collector to the working electrode, a preparation process, a coating process, a drying process, and a peeling process are performed. In the preparation process, the working electrode current collector 103 is placed on a release paper that is placed on a flat surface. The release paper is a release paper used in the molding process of a substance that exhibits temporary adhesion.

[0056] In the coating process, the working electrode 104, which is made into a paste by mixing carbon dioxide adsorbent, conductive additive, and binder, is applied to the upper surface of the working electrode current collector 103 after the preparation process, i.e., the surface opposite the release paper, by screen printing or the like. As a result, the paste-like working electrode 104 penetrates not only the upper surface of the working electrode current collector 103 but also into the working electrode opening 103b.

[0057] In the drying process, the working electrode 104 coated on the working electrode current collector 103 after the coating process is dried. This hardens the working electrode 104. Therefore, the working electrode 104 is formed by solidifying fine particles of carbon dioxide adsorbent and fine particles of conductive additive together with a binder. In the drying process, the working electrode current collector 103 and the working electrode 104 may be heated to speed up the drying process. Alternatively, the working electrode current collector 103 and the working electrode 104 may be placed in a low-pressure environment.

[0058] In the peeling process, the release paper is peeled off the working electrode current collector 103. In the peeling process, when peeling the release paper off the working electrode current collector 103, there is a possibility that a part of the working electrode 104 may peel off together with the release paper, resulting in a portion of the working electrode 104 being damaged. Therefore, in the peeling process, it is desirable to peel off the release paper in a way that does not cause any damage to the working electrode 104.

[0059] Through the above process, in the current collector attachment process on the working electrode side, the working electrode 104 is attached to the working electrode current collector 103. In the current collector attachment process on the counter electrode side, where the counter electrode 106 is attached to the counter electrode current collector 105, the same preparation process, coating process, drying process, and peeling process are performed.

[0060] Then, a bonding process is performed in which the working electrode current collector 103 and working electrode 104, which were attached by the working electrode current collector attachment process, and the counter electrode current collector 105 and counter electrode 106, which were attached by the counter electrode current collector attachment process, are bonded together with a separator 107 in between. In the bonding process, as is clear from Figures 3 and 4, the working electrode 104 side surface and the counter electrode 106 side surface are bonded together so that they are in contact with the separator 107.

[0061] Subsequently, the power supply 109 is connected to the working electrode side lead-out 103a of the working electrode current collector 103 and the counter electrode side lead-out 105a of the counter electrode current collector 105. This manufactures the electrochemical cell 101.

[0062] In the carbon dioxide recovery system 1 according to the first embodiment, a counter electrode enclosure member 110 is placed around the electrochemical cell thus manufactured. In the first embodiment, a film member 111 made of a gas-impermeable material is used as the counter electrode enclosure member 110.

[0063] Furthermore, when placing the film members 111 on the electrochemical cell 101, the placement of the working electrode film 112 and the counter electrode film 113 is carried out under reduced pressure or inert gas conditions.

[0064] Specifically, as shown in Figure 4, the film members 111 consist of a working electrode film 112 and a counter electrode film 113 arranged relative to the electrochemical cell 101. Then, as shown in Figure 5, the working electrode film 112 and the counter electrode film 113 are arranged to surround the electrochemical cell 101 so as to house the electrochemical cell 101 inside.

[0065] The working electrode side film 112 is a film member 111 that is positioned to cover the working electrode side of the electrochemical cell 101. The working electrode side film 112 is positioned to be in close contact with the surfaces of the working electrode current collector 103 and the working electrode 104 in the electrochemical cell 101.

[0066] The working electrode side film 112 is formed to be larger than the working electrode side area of ​​the electrochemical cell 101, and has an opening 112a in its central portion. The opening 112a of the working electrode side film 112 is the same size as the working electrode 104 and is formed to expose the working electrode 104 to the mixed gas.

[0067] On the other hand, the counter electrode side film 113 is a film member 111 that is positioned to cover the counter electrode side of the electrochemical cell 101. The counter electrode side film 113 is positioned to be in close contact with the surfaces of the counter electrode current collector 105 and the counter electrode 106 in the electrochemical cell 101.

[0068] Furthermore, the outer edge of the working electrode film 112 is bonded to the outer edge of the counter electrode film 113 along its entire circumference. As a result, as shown in Figure 5, the electrochemical cell 101 is positioned inside the space formed by the working electrode film 112 and the counter electrode film 113. Because the working electrode film 112 and the counter electrode film 113 are composed of gas-impermeable materials, it is difficult for the mixed gas to flow out or into the space in which the electrochemical cell 101 is positioned, except for the opening 112a.

[0069] Accordingly, according to the first embodiment, by covering the electrochemical cell 101 with a counter electrode surrounding member 110 consisting of an working electrode side film 112 and a counter electrode side film 113, contact of the mixed gas with the counter electrode current collector 105 and the counter electrode 106 can be suppressed.

[0070] Here, we consider the case where a mixed gas containing oxygen comes into contact with the counter electrode 106. When the mixed gas contains oxygen, the oxygen that comes into contact with the counter electrode 106 receives electrical energy, generating reactive oxygen species such as superoxide.

[0071] Such reactive oxygen species can easily oxidize the electroactivating auxiliary material and binder formed from organic materials in the counter electrode 106. When the electroactivating auxiliary material is oxidized, its ability to transfer electrons decreases. Furthermore, when the binder is oxidized, it becomes impossible to retain the electroactivating auxiliary material. As a result, the carbon dioxide recovery capacity of the working electrode 104 may decrease.

[0072] In this regard, in the carbon dioxide recovery system 1 according to the first embodiment, the electrochemical cell 101 is surrounded by the working electrode side film 112 and the counter electrode side film 113 as the counter electrode surrounding member 110, so that the counter electrode 106 is less likely to be exposed to the mixed gas. Therefore, oxidation of the electroactivating auxiliary material and binder of the counter electrode 106 can be suppressed, and a decrease in the recovery capacity of the target gas in the carbon dioxide recovery system 1 can be suppressed.

[0073] Furthermore, when selecting a material that can be used as the film member 111, it is desirable to consider the following points. First, in the first embodiment, in order to bond the outer edges of the working electrode side film 112 and the counter electrode side film 113, the material must have properties or characteristics that correspond to the sealing method at the outer edge.

[0074] For example, when sealing the outer edge by thermocompression bonding (hot plate welding), laser welding, ultrasonic welding, etc., it is necessary that the material has thermoplastic properties, and a configuration having a surface layer or coating of, for example, polypropylene, nylon, or polyvinyl chloride can be adopted.

[0075] Furthermore, when sealing the outer edge with adhesive bonding, it is desirable that the film member 111 has good wettability for the adhesive (i.e., a high surface energy) or a rough surface. For example, laser blasting, plasma treatment, etc., can be used to create a condition suitable for adhesive bonding. A configuration having a surface layer or coating of polyvinyl chloride, nylon, polyethylene terephthalate, etc., can be made suitable for adhesive bonding.

[0076] As mentioned above, the film member 111 must be gas-impermeable. In other words, it is desirable that the film member 111 be made of a material or structure that has gas barrier properties. For example, the film member 111 can be made of a metal vapor-deposited layer such as aluminum or copper, a metal foil layer such as aluminum, or a poorly permeable resin layer such as polyvinylidene chloride.

[0077] As described above, according to the carbon dioxide recovery system 1 of the first embodiment, the electrochemical cell 101 is covered by the working electrode side film 112 and the counter electrode side film 113, which are the counter electrode surrounding members 110, making it difficult to expose the counter electrode 106 to the mixed gas. As a result, the carbon dioxide recovery system 1 can suppress oxidation of the electroactivating auxiliary material and binder of the counter electrode 106, thereby suppressing a decrease in the recovery capacity of the target gas in the carbon dioxide recovery system 1.

[0078] (Second Embodiment) Next, a second embodiment, which differs from the embodiment described above, will be described with reference to Figure 6. In the second embodiment, the film member 111, which is arranged as the counter electrode surrounding member 110, is arranged relative to the electrochemical cell 101. Other basic configurations are the same as in the embodiment described above, so a further explanation will be omitted.

[0079] In the carbon dioxide recovery system 1 according to the second embodiment, the electrochemical cell 101 is constructed by stacking the working electrode current collector 103, working electrode 104, separator 107, counter electrode 106, and counter electrode current collector 105 in the same order as in the embodiment described above.

[0080] As shown in Figure 6, in the electrochemical cell 101 according to the second embodiment, a counter electrode side film 113, which is a film member 111, is arranged as a counter electrode surrounding member 110. The separator 107 in the second embodiment is made of a material that has welding properties to the counter electrode side film 113 and is configured to be larger in size than the counter electrode current collector 105 and the counter electrode 106. Therefore, in the electrochemical cell 101 according to the second embodiment, the outer edge of the separator 107 is positioned outside the outer edges of the counter electrode current collector 105 and the counter electrode 106.

[0081] In the second embodiment, the counter electrode side film 113 is positioned to cover the counter electrode side of the electrochemical cell 101 and is in close contact with the surfaces of the counter electrode current collector 105 and the counter electrode 106. The outer edge of the counter electrode side film 113 is bonded to the outer edge of the separator 107 by welding along its entire circumference.

[0082] Furthermore, the method of bonding the counter electrode film 113 and the separator 107 is not limited to welding, but various methods such as fusion bonding, chemical bonding, and physical bonding can be employed. In addition, other configurations may be used when bonding the counter electrode film 113 and the separator 107; for example, the counter electrode film 113 and the separator 107 may be bonded via an adhesive. The properties required for the constituent material of the counter electrode film 113 are the same as in the first embodiment.

[0083] As shown in Figure 6, in the second embodiment, the gas-impermeable counter electrode side film 113 is arranged to cover the counter electrode current collector 105 and the counter electrode 106 and is bonded to the outer edge of the separator 107. Therefore, no mixed gas flows into the space between the separator 107 and the counter electrode side film 113.

[0084] Furthermore, in the second embodiment, the bonding of the counter electrode film 113 to the separator 107 is performed under reduced pressure or inert gas conditions. Therefore, the space between the separator 107 and the counter electrode film 113 does not contain any mixed gas from the initial state.

[0085] According to the carbon dioxide recovery system 1 of the second embodiment, the counter electrode film 113 and the separator 107 separate the counter electrode current collector 105 and the counter electrode 106, thereby preventing contact of the mixed gas with the counter electrode 106. Therefore, the carbon dioxide recovery system 1 of the second embodiment can suppress oxidation of the electroactivating auxiliary material and binder of the counter electrode 106 with a small number of parts, thereby suppressing a decrease in the recovery capacity of the target gas in the carbon dioxide recovery system 1.

[0086] As described above, according to the carbon dioxide recovery system 1 of the second embodiment, when the separator 107 and the counter electrode side film 113 divide the counter electrode current collector 105 and the counter electrode 106, the effects and advantages obtained from the configuration and operation common to the above-described embodiment can be obtained.

[0087] As shown in Figure 6, by bonding the counter electrode film 113 to the separator 107, the counter electrode current collector 105 and the counter electrode 106 can be isolated from the mixed gas. Therefore, deterioration of the counter electrode 106 and the resulting decrease in the recovery capacity of the target gas can be suppressed with a small number of parts.

[0088] (Third embodiment) Next, a third embodiment, which differs from the embodiments described above, will be explained with reference to Figures 7 and 8. In the third embodiment, the counter electrode surrounding member 110 uses a working electrode side film 112 and a counter electrode side film 113 to suppress the deterioration of the counter electrode 106 while simultaneously ensuring the adhesion of the components of the electrochemical cell 101. Other basic configurations are the same as in the embodiments described above, so a further explanation will be omitted.

[0089] As shown in Figures 7 and 8, in the carbon dioxide recovery system 1 according to the third embodiment, the electrochemical cell 101 is constructed by stacking the working electrode current collector 103, working electrode 104, separator 107, counter electrode 106, and counter electrode current collector 105 in the same order as in the embodiments described above.

[0090] In the third embodiment, the separator 107 of the electrochemical cell 101 has a plurality of holes 107a formed therein. In the separator 107 of the third embodiment, the plurality of holes 107a are arranged along the outer edge of the separator 107 and penetrate the separator 107 in the thickness direction.

[0091] The separator 107 is formed to be larger in size than the working electrode current collector 103, the working electrode 104, the counter electrode current collector 105, and the counter electrode 106. Furthermore, the multiple holes 107a are formed to be located outside the outer edges of the working electrode current collector 103, the working electrode 104, the counter electrode current collector 105, and the counter electrode 106, respectively.

[0092] In the second embodiment, a material having welding properties to the film member 111 is used as the constituent material of the separator 107, but in the third embodiment, welding properties to the film member 111 are not required. In the third embodiment, the separator 107 can be made of various materials as long as the material can prevent physical contact between the working electrode 104 and the counter electrode 106 and suppress electrical short circuits.

[0093] As shown in Figures 7 and 8, in the electrochemical cell 101 according to the third embodiment, a film member 111, consisting of a working electrode side film 112 and a counter electrode side film 113, is arranged as a counter electrode surrounding member 110.

[0094] The working electrode side film 112 is a film member 111 that is arranged to cover the working electrode side of the electrochemical cell 101, similar to the embodiment described above. The working electrode side film 112 is arranged to be in close contact with the surfaces of the working electrode current collector 103 and the working electrode 104 in the electrochemical cell 101.

[0095] The working electrode side film 112 is formed to be larger than the working electrode side area of ​​the electrochemical cell 101, and has an opening 112a in its central portion. The opening 112a of the working electrode side film 112 is the same size as the working electrode 104 and is formed to expose the working electrode 104 to the mixed gas.

[0096] As shown in Figure 8, the outer edge of the working electrode side film 112 is located outside the outer edges of the working electrode current collector 103 and the working electrode 104, and outside the outer edge of the separator 107.

[0097] Furthermore, the counter electrode side film 113 according to the third embodiment is a film member 111 that is arranged to cover the counter electrode side of the electrochemical cell 101. The counter electrode side film 113 is arranged to be in close contact with the surfaces of the counter electrode current collector 105 and the counter electrode 106 in the electrochemical cell 101.

[0098] As shown in Figure 8, the outer edge of the counter electrode film 113 is located outside the outer edges of the counter electrode current collector 105 and the counter electrode 106, and also outside the outer edge of the separator 107.

[0099] In the third embodiment, the working electrode film 112 and the counter electrode film 113 are bonded together by welding inside the multiple holes 107a formed in the separator 107. This fixes the relative positional relationship between the working electrode film 112, the counter electrode film 113, and the separator 107. Furthermore, in the third embodiment, the outer periphery of the working electrode film 112 and the outer periphery of the counter electrode film 113 are welded together over the entire circumference outside the outer periphery of the separator 107.

[0100] In other words, the gas-impermeable counter electrode side film 113 is positioned to cover the counter electrode current collector 105 and the counter electrode 106, and is bonded to the working electrode side film 112 through the holes 107a of the separator 107. Therefore, it is possible to prevent the mixed gas from flowing into the space between the separator 107 and the counter electrode side film 113.

[0101] Furthermore, similar to the embodiments described above, the positioning of the working electrode film 112 and the counter electrode film 113 relative to the electrochemical cell 101 is performed under reduced pressure or inert gas conditions. Therefore, the space between the separator 107 and the counter electrode film 113 does not contain any mixed gas from the initial state.

[0102] According to the carbon dioxide recovery system 1 of the third embodiment, the working electrode side film 112, the counter electrode side film 113, and the separator 107 separate the counter electrode current collector 105 and the counter electrode 106, thereby preventing contact of the mixed gas with the counter electrode 106. Therefore, the carbon dioxide recovery system 1 of the third embodiment can suppress oxidation of the electroactivating auxiliary material and binder of the counter electrode 106, thereby suppressing a decrease in the recovery capacity of the target gas in the carbon dioxide recovery system 1.

[0103] Furthermore, as shown in Figure 8, since the working electrode film 112 and the counter electrode film 113 are welded together inside the multiple holes 107a, the relative positional relationship between the separator 107, the working electrode film 112, and the counter electrode film 113 can be fixed.

[0104] In other words, pressure can be applied in the lamination direction to the working electrode current collector 103 and the working electrode 104 between the separator 107 and the working electrode side film 112, thereby improving the adhesion of the components on the working electrode side in the electrochemical cell 101.

[0105] Similarly, pressure can be applied in the lamination direction to the counter electrode current collector 105 and the counter electrode 106 between the separator 107 and the counter electrode side film 113, thereby improving the adhesion of the components on the counter electrode side in the electrochemical cell 101. In other words, in the carbon dioxide recovery system 1 according to the third embodiment, the adhesion of the components of the electrochemical cell 101 arranged inside can be improved by using the separator 107, the working electrode side film 112, and the counter electrode side film 113.

[0106] Furthermore, the properties required for the working electrode film 112 and the counter electrode film 113 in the third embodiment are the same as those in the embodiments described above. In the third embodiment, it is necessary to apply pressure in the lamination direction by the electrochemical cell 101 using the separator 107, the working electrode film 112, and the counter electrode film 113.

[0107] For this reason, it is desirable that the working electrode film 112 and the counter electrode film 113 according to the third embodiment have mechanical strength to hold the electrochemical cell 101. For example, by having a plastic layer such as polyethylene and making it possible to press-molde, the working electrode film 112 and the counter electrode film 113 can be made to have mechanical strength.

[0108] As described above, according to the carbon dioxide recovery system 1 of the third embodiment, even when the working electrode side film 112 and the counter electrode side film 113 are used as the counter electrode surrounding member 110, the effects and advantages obtained from the same configuration and operation as the above-described embodiment can be obtained.

[0109] Furthermore, in the third embodiment, the working electrode film 112 and the counter electrode film 113 are welded together inside the multiple holes 107a formed in the separator 107, thereby maintaining the relative positional relationship between the separator 107, the working electrode film 112, and the counter electrode film 113. This allows pressure to be applied in the lamination direction to the electrochemical cell 101 placed inside the space composed of the working electrode film 112 and the counter electrode film 113, thereby improving the adhesion of the constituent members of the electrochemical cell 101.

[0110] (Fourth Embodiment) Next, a fourth embodiment, which differs from the embodiments described above, will be explained with reference to Figure 9. In the fourth embodiment, a containment container 115 and resin 116 are used as the counter electrode surrounding member 110. Other basic configurations are the same as in the embodiments described above, so a further explanation will be omitted.

[0111] As shown in Figure 9, in the carbon dioxide recovery system 1 according to the fourth embodiment, the electrochemical cell 101 is constructed by stacking the working electrode current collector 103, working electrode 104, separator 107, counter electrode 106, and counter electrode current collector 105 in the same order as in the embodiments described above.

[0112] In the carbon dioxide recovery system 1 according to the fourth embodiment, a containment container 115 and resin 116 are used as the counter electrode surrounding member 110. As shown in Figure 9, the containment container 115 is formed in the shape of a box with one side (the top side in Figure 9) open. The containment container 115 is made of a gas-impermeable material and is formed to accommodate an electrochemical cell 101 inside.

[0113] An electrochemical cell 101 is placed inside the containment container 115. The electrochemical cell 101 is positioned so that the counter electrode 106 side is in contact with the bottom surface of the containment container 115, and the working electrode 104 side is exposed.

[0114] As shown in Figure 9, inside the containment container 115, resin 116 is placed in the space between the inner surface of the containment container 115 and the electrochemical cell 101. The resin 116 is a gas-impermeable resin material and is filled into the space between the containment container 115 and the electrochemical cell 101 by resin potting.

[0115] The following are the required material properties or characteristics of the resin 116 to be filled by resin potting. First, in order to simultaneously seal the working electrode 104 and the counter electrode 106, the resin 116 must have electrical insulating properties. Second, in order to realize resin potting, the resin 116 must have fluidity and curability. Furthermore, in order to keep the electrochemical cell 101 inside the containment container 115, the resin 116 must have adhesive properties to the containment container 115, which is the other counter electrode surrounding member 110. Examples of resins 116 that satisfy these conditions include two-component curing epoxy resins and two-component curing silicone resins.

[0116] The amount of resin 116 filled into the containment container 115 by resin potting is determined so as to cover the surfaces of the counter electrode 106 and the counter electrode current collector 105 of the electrochemical cell 101 placed inside, while keeping the working electrode 104 exposed from the resin 116. By curing the resin 116 filled into the containment container 115 by resin potting, the placement of the counter electrode surrounding member 110 for the electrochemical cell 101 according to the fourth embodiment is completed.

[0117] Furthermore, the placement of the electrochemical cell 101 inside the containment container 115 and the resin potting work inside the containment container 115 are carried out under reduced pressure or inert gas conditions.

[0118] As shown in Figure 9, in the fourth embodiment, the electrochemical cell 101 is covered at least by the containment container 115 and resin 116, which are the counter electrode surrounding member 110, with the counter electrode current collector 105 and the counter electrode 106 covered. Therefore, it is possible to prevent the mixed gas from flowing into the space formed between the electrochemical cell 101 and the inside of the containment container 115.

[0119] According to the carbon dioxide recovery system 1 of the fourth embodiment, the containment container 115 and resin 116 cover the counter electrode current collector 105 and the counter electrode 106, thereby preventing contact of the mixed gas with the counter electrode 106. Therefore, the carbon dioxide recovery system 1 of the fourth embodiment can suppress oxidation of the electroactivating auxiliary material and binder of the counter electrode 106, thereby suppressing a decrease in the recovery capacity of the target gas in the carbon dioxide recovery system 1.

[0120] As described above, according to the carbon dioxide recovery system 1 of the fourth embodiment, even when a containment container 115 is used as the counter electrode surrounding member 110, the effects and advantages derived from the same configuration and operation as the above-described embodiment can be obtained.

[0121] By placing the electrochemical cell 101 inside the containment container 115 and preventing the inflow of the mixed gas into the containment container 115, oxidation of the electroactivating auxiliary material and binder of the counter electrode 106 can be suppressed.

[0122] Furthermore, by filling the space between the containment container 115 and the electrochemical cell 101 with a gas-impermeable resin 116, contact of the mixed gas with the counter electrode current collector 105 and counter electrode 106 of the electrochemical cell 101 can be reliably prevented. Accordingly, the carbon dioxide recovery system 1 according to the fourth embodiment can suppress a decrease in the recovery capacity of the target gas in the carbon dioxide recovery system 1.

[0123] In the fourth embodiment, the containment container 115, which serves as the counter electrode surrounding member 110, was made of resin, but the embodiment is not limited to this. The containment container 115 can be made of various materials as long as it is gas-impermeable; for example, metal may be used.

[0124] Furthermore, in the fourth embodiment, a resin 116 filled with resin potting is used as the counter electrode surrounding member 110, and as a member used together with the containment container 115, but the embodiment is not limited to this. Different members and methods can be used as long as the inflow and outflow of the mixed gas into and out of the containment container 115 can be suppressed. For example, a gas-impermeable film member 111 may be placed to seal the space between the opening edge of the containment container 115 and the electrochemical cell 101, thereby suppressing the inflow and outflow of the mixed gas into and out of the space created between the counter electrode 106 and the inside of the containment container 115.

[0125] (Fifth embodiment) Next, a fifth embodiment, which differs from the embodiments described above, will be described with reference to Figure 10. In the fifth embodiment, a different counter-pole surrounding member 110 is used compared to the embodiments described above. Other basic configurations are the same as in the embodiments described above, so a further explanation will be omitted.

[0126] In the carbon dioxide recovery system 1 according to the fifth embodiment, the electrochemical cell 101 is constructed by stacking the working electrode current collector 103, working electrode 104, separator 107, counter electrode 106, and counter electrode current collector 105 in the same order as in the embodiments described above.

[0127] As shown in Figure 10, in the carbon dioxide recovery system 1 according to the fifth embodiment, resin 116 is used as the counter electrode surrounding member 110. In the fifth embodiment, the resin 116 is positioned relative to the electrochemical cell 101 by molding.

[0128] Specifically, an example of a procedure for placing resin 116 on an electrochemical cell 101 by molding will be described. First, a mold is prepared that has a space large enough to accommodate the electrochemical cell 101. Next, the electrochemical cell 101 is placed inside the space formed in the mold with the counter electrode side facing downwards.

[0129] A resin 116, which serves as a counter electrode surrounding member 110, is injected into the mold in which the electrochemical cell 101 is placed. The resin 116 is thermoplastic and gas-impermeable, and is injected into the space in a fluid state. The amount of resin 116 injected into the space is determined so as to cover the surfaces of the counter electrode 106 and the counter electrode current collector 105, while keeping the working electrode 104 exposed from the resin 116.

[0130] After injecting a predetermined amount of resin 116 into the mold cavity, the mold is cooled to harden the resin 116 inside the cavity. Once the resin 116 has hardened, the electrochemical cell 101 containing the resin 116 is removed from the mold, as shown in Figure 10, and the molding process is completed.

[0131] Furthermore, it is preferable that the molding of the resin 116 onto the electrochemical cell 101 be carried out under reduced pressure or inert gas conditions.

[0132] In the fifth embodiment, by performing the molding process described above, an electrochemical cell 101 in which resin 116 is arranged as a counter electrode surrounding member 110 can be obtained. Since the resin 116 covers at least the counter electrode current collector 105 and the counter electrode 106, contact of the mixed gas with the counter electrode 106 can be prevented. Therefore, the carbon dioxide recovery system 1 according to the fifth embodiment can suppress oxidation of the electroactivating auxiliary material and binder of the counter electrode 106, thereby suppressing a decrease in the recovery capacity of the target gas in the carbon dioxide recovery system 1.

[0133] The following points can be mentioned regarding the material properties or characteristics required of the resin 116 used in the molding process. First, in order to simultaneously seal the working electrode 104 and the counter electrode 106, the resin 116 must have electrical insulating properties. Furthermore, in order to realize the molding process, the resin 116 must have fluidity and curability.

[0134] Furthermore, in order to prevent contact of the mixed gas with the counter electrode 106, the resin 116 must have gas impermeability (i.e., gas barrier properties). Also, in order to hold the electrochemical cell 101 inside the molded resin 116, the resin 116 must have a certain level of mechanical strength. An example of a resin 116 that satisfies these conditions is a silica filler-containing epoxy resin.

[0135] As described above, according to the carbon dioxide recovery system 1 of the fifth embodiment, even when a molded resin 116 is used as the counter electrode surrounding member 110, the effects and advantages derived from the common configuration and operation of the above-described embodiment can be obtained.

[0136] (Other embodiments) The present invention is not limited to the embodiments described above, and can be modified in various ways without departing from the spirit of the invention. Furthermore, the means disclosed in each of the above embodiments may be combined as appropriate to the extent that they are feasible.

[0137] (a) In the embodiments described above, an example was given in which the gas recovery system according to the disclosure is applied to a carbon dioxide recovery system 1 that recovers carbon dioxide from a mixed gas. However, the application of the gas recovery system according to the disclosure is not limited to this. The gas recovery system according to the disclosure may also be applied to a system that recovers specific types of gases other than carbon dioxide from a mixed gas. For example, nitrogen oxide gas (NOx) and sulfur oxide gas (SOx) can be used as the gas to be recovered in the gas recovery system.

[0138] (b) In the third embodiment described above, a single opening 112a of the working electrode side film 112 was used, which was approximately the same size as the working electrode 104. However, the embodiment is not limited to this. The opening 112a only needs to expose the working electrode 104 to the mixed gas, and it is also possible to have multiple openings.

[0139] When multiple openings are arranged over an area roughly equivalent to that of the working electrode 104, the frame portion forming the opening edges of the multiple openings will be positioned within the same area as the working electrode 104. The frame portion can apply pressure within the area of ​​the working electrode 104 in a direction that presses the constituent materials of the electrochemical cell 101 in the lamination direction. In other words, by composing the opening 112a of the working electrode side film 112 with multiple openings, the adhesion of the constituent materials in the electrochemical cell 101 can be improved. [Explanation of symbols]

[0140] 1. Carbon dioxide capture system 101 Electrochemical cell 103 Working electrode current collector 104 Working electrode 105 Counter electrode current collector 106 Opposite 107 Separator 110 Counter-pole surrounding member 111 Film component

Claims

[Claim 1] A gas recovery system that recovers a target gas from a mixed gas by an electrochemical reaction, An electrochemical cell (101) is constructed by stacking and arranging the following: a working electrode (104) that adsorbs the gas to be recovered; a counter electrode (106) that exchanges electrons with the working electrode; a separator (107) that is placed between the working electrode and the counter electrode to prevent physical contact between the working electrode and the counter electrode and suppress electrical short circuits; a working electrode current collector (103) that abuts against the working electrode and electrically connects the working electrode and the counter electrode; and a counter electrode current collector (105) that abuts against the counter electrode and electrically connects the working electrode and the counter electrode. The electrochemical cell is provided with a counter electrode surrounding member (110) which is positioned to cover the counter electrode and the counter electrode current collector, and which suppresses contact between the mixed gas and the counter electrode. The counter electrode surrounding member (110) is composed of film members (111, 112, 113) made of a material that is impermeable to the mixed gas, Multiple holes (107a) are formed on the outer edge of the separator, passing through the separator. The film member is arranged to cover the counter electrode and the counter electrode current collector, and is joined inside the plurality of holes, at least via the outside of the outer edge of the separator, with the outer edge of the separator sandwiched between them, in a gas recovery system.

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