WO2018146809A1 - Electrochemical cell stack - Google Patents

Abstract

An electrochemical cell stack according to an embodiment of the present invention comprises an electrochemical cell, first and second separators, first and second collectors, a sealing material, and a member. The electrochemical cell comprises a hydrogen electrode, an electrolyte layer, and an oxygen electrode, and includes first and second main surfaces. The first and second separators face the first and second main surfaces, respectively. The first collector is disposed between the first main surface and the first separator, and electrically connects the electrochemical cell and the first separator. The second collector is disposed between the second main surface and the second separator, and electrically connects the electrochemical cell and the second separator. The sealing material is disposed between the first main surface and the first separator and forms a space between the electrochemical cell and the first separator. The member is disposed between the second main surface and the second separator and has a greater compressive strength than the second collector.

Description

Electrochemical cell stack

Embodiments of the present invention relate to an electrochemical cell stack.

Solid oxide electrochemical cells are being developed as fuel cells for power generation, electrolysis cells for hydrogen production, and power storage systems that combine these. Since the solid oxide electrochemical cell uses a solid oxide as an electrolyte, the operating temperature is high (for example, 600 to 1000 ° C.), and a high reaction rate can be obtained without using an expensive noble metal catalyst. Is possible. For this reason, when this is operated as a fuel cell (solid oxide fuel cell: SOFC), high power generation efficiency is obtained, and when it is operated as an electrolysis cell (solid oxide type electrolysis cell: SOEC), it is high at a low electrolysis voltage. Hydrogen can be produced efficiently.

In order to generate a lot of power and hydrogen, a plurality of electrochemical cells are stacked to form an electrochemical cell stack. At this time, in order to prevent gas leakage in the electrochemical cell, the sealing material is pressed and sealed. As a result, stress is applied from the sealing material to the electrochemical cell. Since the solid oxide electrochemical cell is generally made of a ceramic material, it may be deformed or damaged by this stress (particularly bending stress).

JP 2014-041704 A JP 2016-126893 A

An object of the present invention is to provide an electrochemical cell stack that facilitates sealing an electrochemical cell without damaging it.

The electrochemical cell stack according to the embodiment includes an electrochemical cell, first and second separators, first and second current collectors, a sealing material, and a member. The electrochemical cell includes a hydrogen electrode, an electrolyte layer, and an oxygen electrode, and has first and second main surfaces. The first and second separators face the first and second main surfaces, respectively. The first current collector is disposed between the first main surface and the first separator, and electrically connects the electrochemical cell and the first separator. The second current collector is disposed between the second main surface and the second separator, and electrically connects the electrochemical cell and the second separator. The sealing material is disposed between the first main surface and the first separator, and forms a space between the electrochemical cell and the first separator. The member is disposed between the second main surface and the second separator, and has a higher compressive strength than the second current collector.

1 is an exploded perspective view of an electrochemical cell stack 10 according to an embodiment. It is an exploded sectional view of electrochemical cell stack 10 concerning an embodiment. It is sectional drawing of the electrochemical cell stack 10 which concerns on embodiment. It is sectional drawing of the electrochemical cell stack 10a which concerns on the modification 1. It is sectional drawing of the electrochemical cell stack 10b which concerns on the modification 2. It is sectional drawing of the electrochemical cell stack 10c which concerns on the modification 3.

Hereinafter, although the solid oxide electrochemical cell stack according to the embodiment will be described, the present invention is not limited to the following embodiment and examples. Moreover, the schematic diagram referred in the following description is a figure which shows the positional relationship of each structure, The ratio of the magnitude | size of a particle | grain, the thickness of each layer, etc. do not necessarily correspond with an actual thing.

FIG. 1 is an exploded perspective view illustrating a configuration of an electrochemical cell stack 10 according to the embodiment. 2 and 3 are an exploded cross-sectional view and a cross-sectional view schematically showing a partial cross section of the electrochemical cell stack 10 according to the embodiment.
The electrochemical cell stack 10 is a flat plate type, in which an electrochemical cell 11, separators 12 and 13, an insulating layer 14, a sealing material 15, and current collectors 16 and 17 are laminated.

Here, for ease of understanding, only one electrochemical cell 11 is shown, but it is usual to stack several to several tens of electrochemical cells 11. That is, usually, a plurality of cell units composed of the electrochemical cell 11, separators 12 and 13, insulating layer 14, sealing material 15, and current collectors 16 and 17 are stacked vertically.

Electrodes and end plates are added to the upper and lower ends of the electrochemical cell stack 10 (not shown). Moreover, a heater, a power supply, and a controller are added as needed. The heater generates heat by current from the power source and heats the electrochemical cell 11. The controller controls the heater, power supply, and the like.

The electrochemical cell 11 is a hydrogen support type having a planar shape, and a hydrogen electrode 112, an electrolyte layer 113, and an oxygen electrode 114 are sequentially stacked on a support substrate 111. That is, the electrochemical cell 11 includes a hydrogen electrode 112, an electrolyte layer 113, and an oxygen electrode 114, and has first and second main surfaces.
At the time of power generation, for example, a reducing agent such as hydrogen and an oxidizing agent such as oxygen react electrochemically to generate electric energy and water vapor. During electrolysis, water vapor or the like is reduced by electrolysis at the hydrogen electrode 112 and oxygen ions are released from the oxygen electrode 114.

The support substrate 111 is a layer that serves as a support for the electrochemical cell 11, and maintains or improves the mechanical strength of the electrochemical cell 11.

The support substrate 111 is made of a porous material having an appropriate porosity for allowing gas to pass therethrough. The thickness of the support substrate 111 is preferably in the range of 200 μm to 2 mm, for example. Both mechanical strength and gas permeability can be secured.

The hydrogen electrode 112 includes catalyst particles and oxygen ion conductive oxide particles. Examples of the catalyst include metals such as nickel, silver, and platinum, and metal oxides such as nickel oxide and cobalt oxide. Examples of the oxygen ion conductive oxide include ceria-based oxides such as samaria-stabilized ceria (SDC) or gadolinia-stabilized ceria (GDC), or zirconia-based oxides such as yttria-stabilized zirconia (YSZ). Can be mentioned. As the oxygen ion conductive oxide, an oxide constituting the electrolyte layer 113 may be used.

The thickness of the hydrogen electrode 112 can be set as appropriate, for example, in the range of 50 μm to 1000 μm.

The electrolyte layer 113 is a solid oxide layer having electronic insulation and oxygen ion conductivity. Examples of the solid oxide include stabilized zirconia, perovskite oxide, and ceria (CeO ₂ ) -based electrolyte solid solution.
Stabilized zirconia is zirconia in which a stabilizer is dissolved in zirconia. Examples of the stabilizer include Y ₂ O ₃ , Sc ₂ O ₃ , Yb ₂ O ₃ , Gd ₂ O ₃ , Nd ₂ O ₃ , CaO, and MgO. Examples of the perovskite oxide include LaSrGaMg oxide, LaSrGaMgCo oxide, and LaSrGaMgCoFe oxide. As the ceria-based electrolyte solid solution, a solid solution in which Sm ₂ O ₃ , Gd ₂ O ₃ , Y ₂ O ₃ , La ₂ O ₃ , or the like is dissolved in a material containing CeO ₂ can be given.

The electrolyte layer 113 has electronic insulation and oxygen ion conductivity within a temperature range of 600 to 1000 ° C., for example. Within this temperature range, oxygen ions can pass through the electrolyte layer 113.
In addition, the thickness of the electrolyte layer 113 can be set as appropriate, and can be in the range of 5 μm to 500 μm, for example.

The oxygen electrode 114 is made of a material that can efficiently dissociate oxygen and has electron conductivity. Examples of this material include lanthanum, strontium, manganese (LaSrMn) -based perovskite oxide (LSM), LaSrCo oxide (LSC), LaSrCoFe oxide (LSCF), LaSrFe oxide (LSF), LaSrMnCo oxide (LSMC). ), LaSrMnCr oxide (LSMC), LaCoMn oxide (LCM), LaSrCu oxide (LSCu), LaSrFeNi oxide (LSFN), LaNiFe oxide (LNF), LaBaCo oxide (LBC), LaNiCo oxide (LNC) LaSrAlFe oxide (LSAF), LaSrCoNiCu oxide (LSCNC), LaSrFeNiCu oxide (LSFNC), LaNi oxide (LN), GdSrCo oxide (GSC), GdSrMn oxide (GSM) PrCaMn oxide (PCaM), PrSrMn oxide (PSM), PrBaCo oxide (PBC), SmSrCo oxide (SSC), NdSmCo oxide (NSC), BiSrCaCu oxide (BSCC), BaLaFeCo oxide (BLFC), BaSrFeCo An oxide (BSFC), a YSrFeCo oxide (YLFC), a YCuCoFe oxide (YCCF), or a YBaCu oxide (YBC) can be used.

The oxygen electrode 114 is a mixture of these oxides, for example, LSM-YSZ, LSCF-SDC, LSCF-GDC, LSCF-YDC, LSCF-LDC, LSCF-CDC, LSM-ScSZ, LSM-SDC, LSM-GDC. But you can.
Furthermore, for example, components such as Pt, Ru, Au, Ag, and Pd may be added to the oxygen electrode 114.
The thickness of the oxygen electrode 114 can be set as appropriate, for example, in the range of 10 μm to 100 μm.

The separators 12 and 13 have functions of supplying a reactive gas (oxidant, reducing agent, or water vapor) to each electrode and collecting current evenly from the entire surface of the electrode. The separators 12 and 13 have through holes 18 serving as an oxygen channel and a fuel channel in order to supply a reaction gas to each electrode. The through hole 18 is, for example, a space that penetrates in the plate thickness direction of the separators 12 and 13 along the opposing sides.

The separators 12 and 13 have recesses 121 and 131 and grooves 122 and 132, respectively, and face the first and second main surfaces of the electrochemical cell 11, respectively.
The electrochemical cell 11 is disposed in the recesses 121 and 131.
A plurality of grooves 122 are arranged on the bottom surface of the recess 121 and are flow paths for supplying the reaction gas of the hydrogen electrode 112 in the X-axis direction.
A plurality of grooves 132 are arranged on the upper surface of the recess 131 and are flow paths for supplying the reaction gas of the oxygen electrode 114 in the Y-axis direction.

The reaction gas (hydrogen electrode gas) of the hydrogen electrode 112 enters the recess 121 from one of the pair of through holes 18 facing in the X-axis direction, flows in the X-axis direction along the groove 122, and reaches the hydrogen electrode 112. The reaction gas that has reacted at the hydrogen electrode 112 passes through the groove 122 from the hydrogen electrode 112 and is discharged from the other through hole 18.
The reaction gas (oxygen electrode gas) of the oxygen electrode 114 enters the recess 131 from one of the pair of through holes 18 facing in the Y-axis direction, flows in the Y-axis direction along the groove 132, and reaches the oxygen electrode 114. The reaction gas that has reacted at the oxygen electrode 114 passes through the groove 132 from the oxygen electrode 114 and is discharged from the other through-hole 18.

In FIG. 1, the hydrogen electrode gas and the oxygen electrode gas flow in directions orthogonal to each other (cross flow), but other configurations can also be employed. For example, the hydrogen electrode gas and the oxygen electrode gas may flow in the same direction within the surface of the electrochemical cell 11 (parallel flow: coflow) or in the reverse direction (counterflow: counterflow).

The separators 12 and 13 are generally formed of a plate-like conductive material in order to collect current evenly from the entire surface of the hydrogen electrode 112 and the oxygen electrode 114. The electrochemical cell 11 is electrically connected to the current collectors 16 and 17 and the separators 12 and 13. Electric power is supplied to the electrochemical cell 11 from the outside through the separators 12 and 13, or electric power is supplied from the electrochemical cell 11 to the outside.

The separators 12 and 13 are preferably made of a material that is conductive at an operating temperature (600 to 1000 ° C.) and has a thermal expansion coefficient close to that of the electrochemical cell 11, such as steel, stainless steel, and a ferritic alloy. The Ferro-based alloy is preferably a Crofer 22-based material or a ZMG-based material, and the stainless steel is preferably SUS310 or SUS430 (JIS standard).
The thickness of the separator 12 is preferably 0.3 to 3 mm.

The separators 12 and 13 and the insulating layer 14 have through holes 19 that penetrate in the stacking direction. Usually, a plurality of through holes 19 are provided around the electrochemical cell stack 10.

A tightening portion (for example, a bolt) is inserted into the through hole 19, and a fixing portion (for example, a nut) is fitted to the end portion and fixed. The electrochemical cell 11, separators 12 and 13, insulating layer 14, sealing material 15, and current collectors 16 and 17 are laminated and fixed by these tightening portions and fixing portions.

The insulating layer 14 is disposed between the separators 12 and electrically insulates between them.
The insulating layer 14 can be made of a material that has high electrical insulation and can withstand high temperatures, such as alumina, zirconia, silica, or a material containing at least these. The insulating layer 14 is desirably dense, but may be porous. The shape of the insulating layer 14 is not particularly limited.

The sealing material 15 is disposed between the electrolyte layer 113 and the separator 13 of the electrochemical cell 11 and prevents gas leakage from between them. The sealing material 15 makes one round around the side of the electrochemical cell 11 and surrounds the current collector 17. That is, the sealing material 15 forms and seals a space between the electrochemical cell 11 and the separator 13. However, the reactive gas can flow into and out of this space (oxygen electrode 114) through the groove 132 (between the upper surface of the separator 13 and the sealing material 15).

The sealing material 15 can be made of a material that has high electrical insulation and can withstand high temperatures, such as alumina, zirconia, silica, or a material containing at least these. This material may be the same as the insulating layer 14.
In order to prevent gas leakage, it is desirable that the sealing material 15 be dense. However, the sealing material 15 may be made of a material that is porous at room temperature and becomes dense when exposed to high temperature under pressure.
The shape of the sealing material 15 is not particularly limited. That is, if it is annular (ring shape), it can be in various shapes such as a circle and a rectangle.

The current collector 16 is disposed between the electrochemical cell 11 and the separator 12 and electrically connects the hydrogen electrode 112 and the separator 12.
The current collector 17 (first current collector) is disposed between the electrochemical cell 11 and the separator 13 and electrically connects the oxygen electrode 114 and the separator 13.

The current collector 16 is divided into current collectors 161 and 162 having different compressive strengths. The current collector 161 (second current collector) has a relatively small compressive strength and is disposed in the center of the electrochemical cell 11. The current collector 162 (a member having a higher compressive strength than the second current collector: the third current collector) has a relatively large compressive strength and is disposed on the outer periphery of the electrochemical cell 11 on the side opposite to the sealing material 15. Is done.

Compressive strength here is expressed by the amount of compression (deformation) for the same pressure, and is an amount corresponding to the Young's modulus. When the compressive strength is large, the amount of compression with respect to the same pressure is small (not easily crushed), and the Young's modulus is large. That is, unlike the breaking strength, the compressive strength generally represents resistance to pressure in the elastic deformation range.

The oxygen electrode 114 is not disposed on the facing surface of the current collector 162, the electrolyte layer 113 is disposed, and the sealing material 15 is disposed on the electrolyte layer 113.

Thus, the compressive strengths of the current collectors 161 and 162 are different in order to reduce bending stress when members such as the electrochemical cell 11 and the separators 12 and 13 are laminated and sealed. As described above, a plurality of members are tightened and fixed by a tightening portion (for example, a bolt) and a fixing portion (for example, a nut). At this time, the sealing material 15 is compressed to some extent to seal the space between the gas chemical cell 11 and the separator 13. For this reason, stress (bending stress) is applied from the sealing material 15 to the electrochemical cell 11, and the electrochemical cell 11 may be bent or damaged.

Since the current collector 162 has a relatively high compressive strength, the current collector 162 is not crushed even when stress is applied from the sealing material 15, and the electrochemical cell 11 is prevented from being bent (bending stress is applied). If the current collector 162 is crushed by the stress from the sealing material 15, the electrochemical cell 11 may be bent and damaged.

The current collector 17 has a small compressive strength to some extent. For example, it is desirable that the current collector 17 has a compressive strength close to or equivalent to the current collector 161. If the compressive strength of the current collector 17 is too large, the distribution of stress applied to the electrochemical cell 11 from the sealing material 15 and the current collector 17 becomes non-uniform, which is not preferable. That is, the stress applied from the current collector 17 to the electrochemical cell 11 may be significantly greater than the stress applied from the sealing material 15 to the electrochemical cell 11.

The current collectors 16 and 17 are preferably conductive at an operating temperature (600 to 1000 ° C.).
The current collector 16 can be made of a material that can withstand a reducing gas, such as a metal (for example, one or more alloys selected from Ni, Au, Pt, Ag, Fe, and Cu).
The current collector 17 is made of a material that can withstand an oxidizing gas, for example, a metal (for example, one or more alloys selected from Ag, Au, and Pt), a conductive oxide (for example, LSM, LSC). , LSCF, LSF, LSMC, LSMC, LCM, LSCu, LS, LN, GSC, GSM, PCaM, PSM, PBC, SSC, NSC, BSCC, BLFC, BSFC, YLFC, YCCF, YBC).

The following methods (1) and (2) can be used to make the compressive strength different between the current collectors 161 and 162.
(1) Different materials are used for the current collectors 161 and 162.
For example, the following combinations are used.
Current collector 161: Ni, Ag, Au, or Pt
Current collector 162: Ti, Fe, Cu, Ni, or an alloy thereof Preferably, the current collector 161 is Ni, the current collector 162 is a Ni alloy, and more preferably, the current collector 161 is porous Ni. The body 162 is made of a Ni alloy.

The current collector 162 may be made of the same material as the separator 12 as follows.
Current collector 161: Ni, Au, or Pt
Current collector 162: Steel, stainless steel, or ferritic alloy Preferably, current collector 161 is Ni and current collector 162 is a ferritic alloy, more preferably current collector 161 is porous Ni and current collector 162. Is referred to as “Crofer22APU”.

Furthermore, it is possible to use a material with low conductivity or virtually no conductivity for the current collector 162. In this case, the current collector 162 does not function as a current collector. However, if the contact area of the current collector 161 is large, sufficient conductivity can be secured between the hydrogen electrode 112 and the separator 12.
Current collector 161: Ni, Au, Pt
Current collector 162: oxide (eg, gallium oxide, zirconia, ceria)
Preferably, the current collector 161 is Ni, the current collector 162 is stabilized zirconia or doped ceria, more preferably the current collector 161 is porous Ni, and the current collector 162 is YSZ or GDC.

(2) Varying the porosity of the current collectors 161 and 162.
A porous metal is used for at least one of the current collectors 161 and 162.
A porous metal is a metal material having a large number of pores. The porous metal can be produced by (a) sintering metal powder or metal fiber, or (b) cooling in a state where gas bubbles are generated in the molten metal.
Even when the metal materials themselves used for the current collectors 161 and 162 are the same, the current collector 161 can be made more porous than the current collector 162 by making the current collector 161 porous.
In addition, both the current collectors 161 and 162 are formed of a porous metal, and the porosity of the current collector 161 is made larger than that of the current collector 162, so that the compressive strength of the current collector 161 is higher than that of the current collector 162. Can be small.
Preferably, the current collector 161 is porous Ni having a high porosity, and the current collector 162 is porous Ni (or non-porous Ni) having a low porosity.

In the present embodiment, the current collector 16 is composed of current collectors 161 and 162 having different compressive strength, and the current collector 162 having high compressive strength is disposed on the opposite side of the sealing material 15 with the electrochemical cell 11 in between. Is done. For this reason, even if a pressure is applied to the sealing material 15, the current collector 162 is not crushed, and the current collector 162 is crushed, so that non-uniformity of stress applied to the electrochemical cell 11 is alleviated. That is, the bending stress to the electrochemical cell 11 at the time of gas sealing is reduced.

(Modification 1)
FIG. 4 is a cross-sectional view schematically showing a partial cross section of the electrochemical cell stack 10a according to the first modification.
Here, the current collector 162 is made of the same material as that of the separator 12 and is integrated.

(Modification 2)
FIG. 5 is a cross-sectional view schematically showing a partial cross section of the electrochemical cell stack 10b according to the second modification.
The electrochemical cell stack 10b is a flat plate type, in which an electrochemical cell 11a, separators 12 and 13, an insulating layer 14, a sealing material 15, and current collectors 16 and 17 are laminated.

The electrochemical cell 11 a is an oxygen support type having a planar shape, and an oxygen electrode 114, an electrolyte layer 113, and a hydrogen electrode 112 are sequentially stacked on a support substrate 111. That is, in the electrochemical cell stack 10b, the hydrogen electrode 112 and the oxygen electrode 114 are interchanged as compared with the electrochemical cell stack 10.

The current collector 17 is disposed between the electrochemical cell 11 and the separator 12 and electrically connects the hydrogen electrode 112 and the separator 12.
The current collector 16 is disposed between the electrochemical cell 11 and the separator 13 and electrically connects the oxygen electrode 114 and the separator 13.

The current collector 16 includes current collectors 161 and 162 having different compressive strengths. The current collector 161 has a relatively small compressive strength and is disposed at the center of the electrochemical cell 11. The current collector 162 has a relatively large compressive strength and is disposed on the outer periphery of the electrochemical cell 11.
The hydrogen electrode 112 is not disposed on the facing surface of the current collector 162, the electrolyte layer 113 is disposed, and the sealing material 15 is disposed on the electrolyte layer 113.

Since the current collector 162 has a relatively high compressive strength, the current collector 162 is not crushed even when stress is applied from the sealing material 15, and the electrochemical cell 11 is prevented from being bent (bending stress is applied).

As described above, the current collector 17 has a small compressive strength to some extent. For example, it is desirable that the current collector 17 has a compressive strength close to or equivalent to the current collector 161.

The current collector 17 can be made of a material that can withstand a reducing gas, such as a metal (for example, one or more alloys selected from Ni, Au, Pt, Ag, Fe, and Cu).
The current collector 16 is made of a material that can withstand an oxidizing gas, such as a metal (for example, one or more alloys selected from Ag, Au, and Pt), and a conductive oxide (for example, LSM, LSC). , LSCF, LSF, LSMC, LSMC, LCM, LSCu, LS, LN, GSC, GSM, PCaM, PSM, PBC, SSC, NSC, BSCC, BLFC, BSFC, YLFC, YCCF, YBC).
In the electrochemical cell stack 10b, since the atmosphere to which the current collectors 16 and 17 are exposed is opposite to that of the electrochemical cell stack 10, the constituent materials thereof are switched.

The following methods (1) and (2) can be used to make the compressive strength different between the current collectors 161 and 162.
(1) Different materials are used for the current collectors 161 and 162.
For example, the following combinations are used.
Current collector 161: Ag, Au, or Pt
Current collector 162: Alloy containing Ag, Au, or Pt Preferably, the current collector 161 is Ag and the current collector 162 is an Ag alloy, and more preferably, the current collector 161 is porous Ag and the current collector 162 is A (non-porous) Ag alloy is used.

The current collector 162 may be made of the same material as the separator 12 as follows.
Current collector 161: Ag, Au, or Pt
Current collector 162: Steel, stainless steel, or ferrite alloy Preferably, the current collector 161 is Ag and the current collector 162 is a ferrite alloy, and more preferably, the current collector 161 is porous Ag and the current collector 162. Is referred to as “Crofer22APU”.

Furthermore, it is possible to use a material with low conductivity or virtually no conductivity for the current collector 162. In this case, the current collector 162 does not function as a current collector. However, if the contact area of the current collector 161 is large, sufficient conductivity can be secured between the oxygen electrode 114 and the separator 12.
Current collector 161: Ag, Au, Pt
Current collector 162: General ceramic, oxide (preferably gallium oxide, zirconia, ceria)
Preferably, the current collector 161 is Ag, the current collector 162 is stabilized zirconia or doped ceria, more preferably the current collector 161 is porous Ag, and the current collector 161 is YSZ or GDC.

(2) Varying the porosity of the current collectors 161 and 162.
A porous metal is used for at least one of the current collectors 161 and 162.
Even if the metal materials themselves used for the current collectors 161 and 162 are the same, the current collector 161 can be made porous so that the compressive strength of the current collector 171 can be made smaller than that of the current collector 162.
In addition, both the current collectors 161 and 162 are formed of a porous metal, and the porosity of the current collector 161 is made larger than that of the current collector 162, so that the compressive strength of the current collector 161 is higher than that of the current collector 162. Can be small.
Preferably, the current collector 161 is a porous Ag having a high porosity, and the current collector 161 is a porous Ag (or non-porous Ag) having a low porosity.

(Modification 3)
FIG. 6 is a cross-sectional view schematically showing a partial cross section of an electrochemical cell stack 10c according to Modification 3.
The electrochemical cell stack 10c includes the electrochemical cell 11a, similar to the electrochemical cell stack 10b, but the current collector 162 is made of the same material as the separator 12 and is integrated.

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

Claims (7)

1. An electrochemical cell comprising a hydrogen electrode, an electrolyte layer, and an oxygen electrode and having first and second main surfaces;
   First and second separators respectively facing the first and second main surfaces;
   A first current collector disposed between the first main surface and the first separator and electrically connecting the electrochemical cell and the first separator;
   A sealing material disposed between the first main surface and the first separator, and forming a space between the electrochemical cell and the first separator;
   A second current collector disposed between the second main surface and the second separator and electrically connecting the electrochemical cell and the second separator;
   A member having a compressive strength greater than that of the second current collector, disposed between the second main surface and the second separator;
   An electrochemical cell stack comprising:
2. The electrochemical cell stack according to claim 1, wherein the member has conductivity and functions as a third current collector that electrically connects the electrochemical cell and the second separator.
3. The sealing material surrounds the first current collector;
   The electrochemical cell stack according to claim 1, wherein the member surrounds the second current collector.
4. The electrochemical cell stack according to claim 1, wherein the member is disposed on the opposite side of the sealing material with respect to the electrochemical cell.
5. The compressive strength of the first current collector is smaller than the compressive strength of the member.
   The electrochemical cell stack according to claim 1.
6. The electrochemical cell stack according to claim 1, wherein the member is made of the same material as the second separator.
7. The electrochemical cell stack according to claim 6, wherein the member is integrated with the second separator.

Images