JP7213537B2 - Electrochemical cells and cell stacks - Google Patents

Description

The present invention relates to electrochemical cells and cell stacks.

There is an increasing demand for hydrogen storage systems that store renewable energy as hydrogen fuel. A hydrogen storage system uses surplus power to electrolyze water in a water electrolysis cell to store energy in the form of hydrogen, and when power is insufficient, the stored hydrogen is generated by a fuel cell to compensate for the power shortage.

Electrochemical cells (water electrolysis cells and fuel cells) require efficient and stable hydrogen decomposition and power generation. However, especially in a water electrolysis cell, uneven contact between a metal electrode and a catalyst-carrying electrode or between a catalyst-carrying electrode and a solid electrolyte leads to power concentration (application of high voltage), resulting in deterioration of the electrodes.

In conventional electrochemical cells, the anode unit and the cathode unit are fastened by screwing at about 4 to 6 locations. It is not easy to equalize the holding pressure by tightening the screws, and the deterioration of the electrodes as described above occurs.

Japanese Patent No. 5553308

SUMMARY OF THE INVENTION In view of the problems of the prior art as described above, it is an object of the present invention to provide an electrochemical cell and a cell stack capable of efficient and stable reaction.

In order to solve the above problems, an electrochemical cell according to the present invention has the following configuration. That is, one aspect of the present invention includes a first unit including a first electrode, a second unit including a second electrode, a catalyst-carrying electrode, and an electrolyte membrane, and An electrochemical cell in which the catalyst-carrying electrode and the electrolyte membrane are sandwiched therebetween. In this aspect, the first unit includes a fitting recess and a first recess provided on the bottom surface of the fitting recess, the first electrode is provided in the first recess, and the second The unit includes a fitting protrusion that fits into the fitting recess, and a second recess provided on an upper surface of the fitting protrusion, and the second electrode is provided in the second recess. , the fitting concave portion and the fitting convex portion are fitted.

By adopting the spigot structure in this way, uneven contact between the electrode and the electrolyte membrane and the catalyst-carrying electrode can be suppressed. As a result, the electrochemical cell according to this aspect can achieve efficient and stable reactions. In addition, since the spigot structure is adopted, there is also the advantage that assembly is easy.

In this aspect, the bottom surface of the fitting recess and the top surface of the fitting protrusion may be in contact directly or via an insulating sheet. As described above, the contact between the bottom surface of the fitting recess and the top surface of the fitting projection defines the contact between the first electrode/electrolyte membrane and the catalyst-carrying electrode/second electrode, so that uneven contact can be suppressed.

In this aspect, the distance between the surface of the first electrode and the surface of the second electrode is preferably smaller than the thickness of the electrolyte membrane and the catalyst-carrying electrode in an unloaded state. The electrolyte membrane and the catalyst-carrying electrode are sandwiched between the first electrode and the second electrode and are in uniform contact with the first electrode and the second electrode.

In this aspect, either the first unit or the second unit is provided with two fluid passages communicating between the electrolyte membrane and the catalyst-carrying electrode and the outside. may be larger in diameter than the fluid passages of the For example, it is preferable that the fluid passages discharging water and oxygen have a larger diameter than the fluid passages supplying water. The larger the diameter of the fluid passage, the slower the flow velocity, so the generated oxygen gas can be discharged more reliably.

In this aspect, grooves or holes may be provided on the surfaces of the first electrode and the second electrode. The grooves can be, for example, serpentine grooves, straight grooves, orthogonal grooves, or combinations thereof. This enables efficient supply and discharge of water and gas.

In this aspect, surfaces of the first electrode and the second electrode may be roughened. Roughening increases the contact area between the electrode and the catalyst-carrying electrode, so the resistance can be reduced.

In this aspect, the first unit has a first external electrode that is electrically connected to the first electrode and extends from the surface opposite to the surface on which the fitting recess is provided to the side surface; The unit may have a second external electrode that is electrically connected to the second electrode and extends from the surface opposite to the surface on which the fitting protrusion is provided to the side surface. Since the external electrodes extend to the sides of the unit in this manner, wiring for power supply is facilitated.

In this aspect, the first unit and the second unit each have a fluid passage for supplying or discharging a fluid on the side surface, and the first external electrode and the second external electrode have the fluid passage. It may be provided on a side different from the side on which it is provided. By providing the fluid passage and the external electrode on different sides in this manner, wiring and piping are facilitated.

A second aspect of the present invention is a cell stack having a plurality of electrochemical cells according to the above aspects and electrically connected in series or in parallel.

Since the cell stack according to this aspect is an assembly of single cells, it is possible to easily identify a failed or deteriorated cell and to replace only the failed or deteriorated cell. In addition, since it is an aggregate of independent single cells, the shape of the stack can be freely determined, and it is possible to provide a cell stack with an appropriate shape according to the usage conditions.

Moreover, by branching off from a distribution pipe for supplying water and supplying water to the electrochemical cell, the flow rate and the amount of power generation can be made constant.

According to the present invention, it is possible to provide an electrochemical cell and cell stack capable of efficient and stable reaction.

FIG. 1 is a structural explanatory view of a water electrolysis cell stack. FIG. 2A is an exploded view of the water electrolysis cell, and FIG. 2B is an assembly view of the water electrolysis cell. 3A is a perspective view of the front side of the anode unit, and FIG. 3B is a perspective view of the back side of the anode unit. 4A to 4C are side view, front view and cross-sectional view of the anode unit, respectively. 5A is a perspective view of the front side of the cathode unit, and FIG. 5B is a perspective view of the back side of the cathode unit. 6A to 6C are side view, front view and cross-sectional view of the cathode unit, respectively. FIG. 7 is a diagram for explaining fitting of the anode unit and the cathode unit. FIG. 8 is a diagram showing the evaluation results of the water electrolysis performance in the case where the metal electrode surface is not processed, the case where the surface is roughened, and the case where cross grooves are provided. FIG. 9 is a diagram showing the results of two evaluations performed using unprocessed metal electrodes in order to evaluate the influence of the measurement order.

Preferred embodiments and examples of the present invention will be described below with reference to the drawings. However, the following embodiments and examples merely exemplify preferred configurations of the present invention, and the scope of the present invention is not limited to those configurations. In addition, unless otherwise specified, the scope of the present invention is limited only to the hardware configuration and software configuration of the apparatus, process flow, manufacturing conditions, dimensions, materials, shapes, etc., in the following description. it's not on purpose.

(overall structure)
This embodiment is a water electrolysis cell stack that uses electric power to electrolyze water. In this embodiment, for example, it is assumed that water is electrolyzed using electric power based on renewable energy such as sunlight, wind power, hydraulic power, and geothermal heat. However, the present embodiments may use power based on fossil fuels, nuclear power, or the like.

FIG. 1 is a configuration explanatory diagram of a water electrolysis cell stack 1 (hereinafter also simply referred to as stack 1) according to the present embodiment. A stack 1 is an assembly in which a plurality of water electrolysis cells 2 (single cells) are laminated. However, since each water electrolysis cell 2 has an independent structure as will be described later, the stack 1 does not necessarily have to stack the water electrolysis cells 2, and the stack shape can be freely determined. Further, although FIG. 1 shows the cell stack 1 including three water electrolysis cells 2, the number of water electrolysis cells 2 may be arbitrary.

The water electrolysis cell 2 is configured including an anode unit 10 and a cathode unit 20 . Electric power is supplied to the anode unit 10 and the cathode unit 20 from a DC power source (not shown), the electrode of the anode unit 10 is set as the anode (oxygen generating electrode), and the electrode of the cathode unit 20 is set as the cathode (hydrogen generating electrode). .

Water is supplied to the anode unit 10 of each water electrolysis cell 2 through a manifold branched from a common supply pipe 3, and oxygen generated at the anode is taken out from the oxygen extraction pipe 4 together with the water. Hydrogen generated at the cathode of the cathode unit is taken out from the hydrogen take-out tube 5 and led to a hydrogen storage section (not shown).

The structure of the water electrolysis cell 2 will be described in more detail. 2A is an exploded view of the water electrolysis cell 2, and FIG. 2B is an assembly view of the water electrolysis cell 2. FIG. 3A is a perspective view of the front surface (inside during assembly) of the anode unit 10, and FIG. 3B is a perspective view of the rear surface (outside during assembly) of the anode unit 10. FIG. 4A-4C are a side view, a front view, and a cross-sectional view of the anode unit 10. FIG. 5A is a perspective view of the front surface (inside during assembly) of the cathode unit 20, and FIG. 5B is a perspective view of the back surface (outside during assembly) of the cathode unit 20. FIG. 6A-6C are a side view, a front view, and a cross-sectional view of the cathode unit 20. FIG.

As shown in FIGS. 2A and 2B, the water electrolysis cell 2 includes an insulating sheet 40a, a metal mesh 50a, a membrane electrode assembly (MEA) 30, a metal mesh 50b, and an insulating sheet 40b between the anode unit 10 and the cathode unit 20. has a structure in which The anode unit 10 and cathode unit 20 are fixed by bolts 63 and nuts 61 and 62 .

(anode unit)
A main body 101 of the anode unit 10 is made of, for example, an acrylic resin and has a square plate shape. The material of the main body 101 is not particularly limited, and it may be an insulating material other than acrylic resin, or even if it is a conductive material, an insulating material may be sandwiched between other conductive members. Moreover, the shape of the main body 101 is not limited to a square, and may be any shape. A circular fitting recess 102 is provided on the surface of the main body 101, and a square recess 103 (first recess) is further provided on the bottom surface 102a of the fitting recess 102. As shown in FIG. The shape of the fitting concave portion 102 may be any shape other than the circular shape as long as it corresponds to the shape of the fitting convex portion 202 .

A metal electrode 104 for supplying power to the MEA 30 is provided in the recess 103 . The material of the metal electrode 104 is not particularly limited as long as it has conductivity and corrosion resistance. For example, titanium, nickel, SUS (stainless steel), etc. can be used. The electrodes do not necessarily have to be made of metal, and carbon (graphite) electrodes such as graphene, graphite, carbon nanotubes, or other semiconductor electrodes can be used as long as they have conductivity and corrosion resistance. The surface of the metal electrode 104 may be roughened, or may be provided with at least one of meandering grooves, orthogonal grooves, straight grooves and holes. A base portion 104 a of the metal electrode 104 is in contact with the external electrode 105 and fixed to the main body 101 together with the external electrode 105 from the back side of the main body 101 by screws 106 . A base portion 104a of the metal electrode 104 is provided with an O-ring 104b for sealing. The external electrode 105 is an electrode extending from the back surface of the main body 101 to the side surface. The external electrode 105 is connected to a DC power supply.

A joint 107 that connects to the water supply pipe 3 is provided on a side of the main body 101 that is different from the side on which the external electrode 105 is provided. Water supplied via fitting 107 flows into recess 103 through fluid passage 108 and opening 109 . A joint 110 is provided on the side surface opposite to the joint 107 . Oxygen (and water) generated at the anode during water electrolysis is discharged from joint 110 to oxygen extraction pipe 4 via opening 112 and fluid passage 111 . Thus, the space of the recess 103 communicates with the outside through the opening 109, the fluid passage 108, the joint 107, the opening 112, the fluid passage 111, and the joint 110. FIG.

Here, the diameters of fluid passage 108 and opening 109 for supplying water are set smaller than the diameters of fluid passage 111 and opening 112 for discharging water and oxygen. Since the smaller the diameter of the fluid passage, the faster the flow velocity of the fluid, the oxygen generated during water electrolysis can more reliably flow toward the opening 112 .

(cathode unit)
A main body 201 of the cathode unit 20 is made of, for example, acrylic resin and has a square plate shape. The material of the main body 201 is not particularly limited, and an insulating material other than acrylic resin may be used. Moreover, the shape of the main body 201 is not limited to a square, and may be any shape. The surface of the main body 201 is provided with a circular fitting projection 202 that fits into the fitting recess 102 of the anode unit 10 . A square concave portion 203 (second concave portion) is provided on the upper surface 202a of the fitting convex portion 202 . The shape of the fitting projection 202 may be other than circular as long as it corresponds to the fitting recess 102 .

A metal electrode 204 for supplying power to the MEA 30 is provided in the recess 203 . The material of the metal electrode 204 is not particularly limited as long as it has conductivity and corrosion resistance. For example, titanium, nickel, SUS (stainless steel), etc. can be used. The electrodes do not necessarily have to be made of metal, and carbon (graphite) electrodes such as graphene, graphite, carbon nanotubes, or other semiconductor electrodes can be used as long as they have conductivity and corrosion resistance. The surface of the metal electrode 204 may be roughened or provided with at least one of meandering grooves, orthogonal grooves, straight grooves and holes. A base portion 204 a of the metal electrode 204 is in contact with the external electrode 205 and fixed to the main body 201 together with the external electrode 205 from the back side of the main body 201 by screws 206 . A base portion 204a of the metal electrode 204 is provided with an O-ring 204b for sealing. The external electrode 205 is an electrode extending from the back surface of the main body 201 to the side surface. The external electrode 205 is connected to a DC power supply.

A joint 207 for extracting hydrogen generated during water electrolysis is provided on a side of the main body 201 that is different from the side on which the external electrode 205 is provided. Hydrogen is discharged outside from joint 207 via opening 209 and fluid passage 208 . Thus, the space of the recess 203 communicates with the outside through the opening 209, the fluid passage 208, and the joint 207. As shown in FIG. Along with the hydrogen, part of the water passes through the ion exchange membranes between the MEAs 30 and is discharged to the outside via the openings 209 , the fluid passages 208 and the joints 207 .

(Surface processing of electrodes)
Either one or both of the surfaces of the metal electrode 104 of the anode unit 10 and the metal electrode 204 of the cathode unit may be grooved or roughened (sanded). The grooves can be, for example, meandering grooves, orthogonal grooves, striped grooves. The surface roughening may be provided by sandblasting, for example. When both the metal electrode 104 and the metal electrode 204 are processed, the same processing may be performed on both electrodes, or different processing may be performed. By subjecting the metal electrodes 104 and 204 to surface processing, the gas generated at the electrodes can be efficiently discharged, and the reaction at the electrodes is not hindered. This improves the water electrolysis performance of the cell.

(MEA: membrane electrode assembly)
The MEA 30 has a structure in which an electrolyte layer (electrolyte membrane) is sandwiched between catalyst-carrying electrodes. The electrolyte layer is ion-permeable and is specifically composed of an ion-exchange membrane. In this embodiment, a known ion exchange membrane used in water electrolysis may be used. Specific examples of ion exchange membranes include solid polymer electrolyte membranes such as perfluorocarbon resins into which ion exchange groups have been introduced. A catalyst-carrying electrode is an electrode that contains a water electrocatalyst on at least the surface portion of the side that contacts the electrolyte layer. Any known water electrocatalyst may be used, and examples thereof include platinum, ruthenium, iridium, rhodium, and alloys and oxides of these metals.

(Insulating sheet)
The insulating sheets 40a and 40b are made of an insulating and flexible material (for example, silicone), and have substantially the same shape as the bottom surface 102a of the fitting recess 102 and the top surface 202a of the fitting projection 202, respectively. It is a circular sheet with openings corresponding to 204 . The insulating sheets 40a and 40b function as sealing materials for sealing the electrolytic reaction portion (the space formed by the recess 103 and the recess 203). The thickness of the insulating sheets 40a and 40b is, for example, 0.1 mm to 0.3 mm. Note that if the housing is insulating, the insulating sheets 40a and 40b may be omitted.

(metal mesh)
The metal meshes 50a, 50b are sandwiched between the metal electrodes 104, 204 and the catalyst carrying electrodes.
The metal meshes 50a and 50b are, for example, SUS 20-100 mesh. The metal meshes 50a, 50b may be omitted if electrical conductivity between the metal electrodes 104, 204 and the catalyst-carrying electrodes can be ensured.

(Mating the anode unit and cathode unit)
Next, with reference to FIG. 7, the fitting of the anode unit 10 and the cathode unit 20 and the sandwiching of the MEA 30 between the metal electrodes 104 and 204 will be described.

The fitting concave portion 102 of the anode unit 10 and the fitting convex portion 202 of the cathode unit 20 are fitted together, and the bottom surface 102a of the fitting concave portion 102 and the top surface 202a of the fitting convex portion 202 are separated via the insulating sheets 40a and 40b. Contact. Therefore, it is desirable that the height (T2') of the fitting protrusion 202 is equal to or greater than the depth (T2) of the fitting recess 102. In this way, the contact between the anode unit 10 and the cathode unit 20 and the positions of the metal electrodes 104 and 204 are defined by the surfaces of the fitting concave portion 102 and the fitting convex portion 202. The pressing pressure of the MEA 30 can be made constant, and contact unevenness can be suppressed.

The thickness of the surface portions of the metal electrodes 104 and 204 is smaller than the depth of the recesses 103 and 203 . Therefore, when the anode unit 10 and the cathode unit 20 are assembled, there is a gap T1 between the surfaces of the metal electrodes 104 and 204 . This interval T1 is made smaller than the sum of the thicknesses of the catalyst-carrying electrodes of the MEA 30 and the metal meshes 50a and 50b (here, the thickness is when no load is applied). Therefore, the metal electrodes 104 and 204 are brought into contact with the catalyst-carrying electrodes of the MEA 30 with uniform pressure during assembly. In this embodiment, for example, the thickness of the surface portions of the metal electrodes 104 and 204 is 2 mm, the depth of the concave portions 103 and 203 is 2.4 mm, and the thickness of the catalyst-supporting electrodes of the MEA 30 (when no load is applied) is 0.8 mm. ˜1.0 mm, and the thickness of each of the metal meshes 50a and 50b is 0.1 mm.

A distance T3 between the bottom surface 102a of the fitting recess 102 and the top surface 202a of the fitting projection 202 during assembly is equal to the thickness of the insulating sheets 40a and 40b. When the insulating sheets 40a and 40b are omitted, the interval T3 is zero. In this embodiment, since the height (T2') of the fitting projection 202 is equal to or greater than the depth (T2) of the fitting recess 102, the upper end portion of the fitting recess 102 and the fitting projection 202 at the time of assembly. The interval T4 between the lower ends satisfies the relationship T4≧T3 (≧0).

In the present embodiment, the external electrode 105 of the anode unit 10 and the external electrode 205 of the cathode unit 20 are assembled so as to be positioned on the side facing the same direction. The joints 107 , 110 , 207 are located on the side faces facing away from the external electrodes 105 , 205 . Therefore, connection of wiring and piping becomes easy. It should be noted that the anode unit 10 and the cathode unit 20 do not necessarily have to be assembled in this direction, and may be assembled in any direction as necessary.

(performance evaluation)
The water electrolysis cell 2 having the configuration described above was produced, and water electrolysis performance was evaluated. The results are shown in FIG. Here, the evaluation was performed for each of the cases where the electrodes 104 and 204 were not surface-processed, where the surfaces were roughened, and where cross-shaped grooves were provided. Roughening is provided by 100 grit sandblasting. The cross grooves have a groove width of 2 mm, a groove depth of 0.2 mm, and a groove interval of 4 mm. This evaluation utilized a PtC/IrOx 5-layer MEA, and the same MEA was used for each evaluation.

In FIG. 8, a graph 81 shows the voltage-current characteristics in the case of no machining, a graph 82 in the case of roughening, and a graph 83 in the case of cross grooves. FIG. 8 also shows how water droplets are dropped on each electrode.

As shown in the figure, a sufficiently large current was obtained even when the electrode surface was not processed, but a large current increase was achieved by roughening the surface and providing cross grooves. Thus, it can be seen that the hydrophilicity/hydrophobicity of the electrode surface affects the performance of water electrolysis.

In the experiment of FIG. 8, the same MEA was used, and measurements were performed in the order of no machining, surface roughening, and cross grooves. Here, taking into consideration the influence of the order of experiments, the measurement without processing was performed again at the end. FIG. 9 shows the evaluation results when using the electrode without processing for the first and second times. Graph 81 is the first measurement, and graph 84 is the second measurement. Thus, the second measurement does not show a large increase in current, indicating that the order of measurement has little effect. That is, it can be seen that the current increase shown in FIG. 8 is due to the surface processing of the electrode.

(Advantageous effect of this embodiment)
In the water electrolysis cell 2 according to the present embodiment, the fitting recess 102 of the anode unit 10 and the fitting protrusion 202 of the cathode unit 20 define contact between these units. Therefore, the pressing pressure between the metal electrodes 104, 204 and the catalyst-supporting electrode and the pressing pressure between the catalyst-supporting electrode and the electrolyte layer can be kept constant. By suppressing contact unevenness, power concentration (high voltage application) can be avoided, and effects such as efficient hydrogen generation and suppression of electrode deterioration can be obtained.

In addition, since the spigot structure is adopted, for example, the MEA 30, the insulating sheets 40a and 40b, etc. are placed on the anode unit 10 with the surface side facing up, and the cathode unit 20 is fitted. , the water electrolysis cell 2 is assembled. Thus, the water electrolysis cell 2 according to this embodiment has the advantage of being easy to assemble.

In addition, in the anode unit 10, the diameter of the fluid passage 108 and the opening 109 for supplying water is smaller than the diameter of the fluid passage 111 and the opening 112 for discharging oxygen and water. (and oxygen) flow rate. Therefore, the oxygen generated by water electrolysis is discharged more reliably, and it is possible to suppress the oxygen from remaining on the electrode.

Moreover, the water electrolysis cell stack 1 obtained by stacking the water electrolysis cells 2 according to this embodiment has the following advantages. Firstly, since each water electrolysis cell 2 is independent, it is possible to individually monitor the operation and identify a failed or deteriorated cell. Also, it can be replaced in cell units. Secondly, since the water electrolysis cells 2 are independent, the water electrolysis cells 2 do not necessarily have to be stacked, and the stack shape can be freely changed according to the usage of the water electrolysis cell stack 1 .

(Modification)
In the above embodiment, the anode unit 10 is provided with the fitting concave portion 102 and the cathode unit 20 is provided with the fitting convex portion 202. Conversely, the anode unit 10 is provided with the fitting convex portion. , the cathode unit 20 may be provided with a fitting recess. Similar effects can be obtained with such a configuration.

Although the shape of the water electrolysis cell 2 is quadrangular, it may be circular or other polygonal shapes, and the shape is not particularly limited.

Although the above embodiment is a water electrolysis cell (stack), a fuel cell (stack) may have a similar structure. That is, the present invention is applicable to both water electrolysis cells (stacks) and fuel cells (stacks).

1: Water electrolysis cell stack 2: Water electrolysis cell 3: Water supply pipe 4: Oxygen removal pipe 5: Hydrogen removal pipe 10: Anode unit 20: Cathode unit 101: Anode unit main body 102: Fitting recess 103: Recess 104: Metal Electrode 105: External electrode 106: Screw 107: Joint 108: Fluid passage 109: Opening 110: Joint 111: Fluid passage 112: Opening 201: Cathode unit main body 202: Fitting convex portion 203: Concave portion 204: Metal electrode 205: External electrode 206: Screw 207: Joint 208: Fluid passage 209: Opening

Claims (9)

a first unit including a first electrode, a second unit including a second electrode, an electrolyte membrane and a catalyst-carrying electrode, wherein the electrolyte membrane and the catalyst-carrying electrode are interposed between the first electrode and the second electrode An electrochemical cell sandwiched by
The first unit includes a fitting recess and a first recess provided on the bottom surface of the fitting recess, wherein the first electrode is provided in the first recess,
The second unit includes a fitting projection having a height equal to or greater than the depth of the fitting recess and fitting into the fitting recess, and a second recess provided on an upper surface of the fitting projection. wherein the second electrode is provided in the second recess,
The fitting concave portion and the fitting convex portion are fitted together ,
the distance between the surface of the first electrode and the surface of the second electrode is smaller than the thickness of the electrolyte membrane and the catalyst-supporting electrode in an unloaded state;
An electrochemical cell characterized by: The bottom surface of the fitting recess and the top surface of the fitting protrusion are in contact directly or via an insulating sheet.
The electrochemical cell of claim 1. Either the first unit or the second unit is provided with two fluid passages communicating between the electrolyte membrane and the catalyst-carrying electrode and the outside,
one fluid passageway having a larger diameter than the other fluid passageway;
3. An electrochemical cell according to claim 1 or 2 . the fluid passage for discharging water and oxygen has a larger diameter than the fluid passage for supplying water;
4. An electrochemical cell according to claim 3 . Grooves are provided on the surfaces of the first electrode and the second electrode,
5. An electrochemical cell according to any one of claims 1-4 . The surfaces of the first electrode and the second electrode are roughened,
5. An electrochemical cell according to any one of claims 1-4 . The first unit has a first external electrode electrically connected to the first electrode and extending from the surface opposite to the surface provided with the fitting recess to the side surface,
The second unit has a second external electrode that is electrically connected to the second electrode and extends from the surface opposite to the surface on which the fitting protrusion is provided to the side surface.
7. An electrochemical cell according to any one of claims 1-6 . The first unit and the second unit have fluid passages for supplying or discharging fluid on their sides,
The first external electrode and the second external electrode are provided on a side surface different from the side surface on which the fluid passage is provided,
8. An electrochemical cell according to claim 7 . Having a plurality of electrochemical cells according to any one of claims 1 to 8 ,
multiple electrochemical cells electrically connected in series or in parallel,
cell stack.

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