JP2014207120A - Solid oxide electrochemical cell stack structure and hydrogen power storage system - Google Patents

Abstract

The present invention provides a solid oxide electrochemical cell stack structure in which heat exchange efficiency is improved and damage to a sealing material provided on a side surface portion can be suppressed. A solid oxide electrochemical cell stack structure includes a plurality of cell stacks and a flat plate heat exchanger disposed between the cell stacks. Each cell stack is formed by laminating a plurality of planar solid oxide electrochemical cells. [Selection] Figure 1

Description

  Embodiments of the present invention relate to a solid oxide electrochemical cell stack structure and a hydrogen power storage system.

  As an electrochemical device, a device in which a plurality of flat electrochemical cells each having a pair of electrodes on both main surfaces of an electrolyte are stacked via a separator is known. In such an electrochemical device, for example, an oxidant such as air is supplied to one electrode in each electrochemical cell, and a reducing agent such as hydrogen is supplied to the other electrode, and these react electrochemically. And used as a fuel cell.

  Among electrochemical devices, those using a solid oxide as an electrolyte have the following characteristics as compared with those using other electrolytes because the operating temperature is as high as 700 to 1000 ° C. That is, in addition to hydrogen, carbon monoxide can be used as a fuel. In addition, since the gas can be reformed inside, a reformer is unnecessary. Furthermore, high power generation efficiency can be expected by moving a gas turbine generator or a steam turbine generator using high-temperature exhaust heat such as exhaust gas.

  In general, in an electrochemical device, from the viewpoint of power generation efficiency and the like, it is required that reaction gases such as an oxidizing agent and a reducing agent react only in an electrochemical cell and do not mix or react in other portions. In order to suppress mixing and reaction other than in the electrochemical cell, it is required to suppress leakage of the reaction gas from the reaction gas flow path and the periphery of the electrochemical cell. In addition, it is required to suppress leakage of the reaction gas from the electrochemical device to the outside atmosphere or the like.

  In order to suppress leakage of the reaction gas, a sealing material is provided between the electrochemical cell and the separator. The sealing material is required to be in close contact with the electrochemical cell and to absorb internal stress or loosening of each part that occurs with a temperature change. As a material of the sealing material, in addition to glass, a layered or high-temperature-expandable mineral such as mica and vermiculite (for example, see Patent Document 1), a material having a thermal expansion / shrinkage property equivalent to a separator or a solid electrolyte (for example, a patent) Document 2) is known.

JP 2011-228171 A JP 2012-109251 A

  In recent years, an electrochemical device using a solid oxide as an electrolyte, specifically, a solid oxide fuel cell (SOFC) or a solid oxide electrolysis cell (SOEC), It is being considered for use in hydrogen power storage systems. Hydrogen power storage systems, for example, produce and store hydrogen by electrolysis of water using renewable energy with large output fluctuations such as solar power and wind power generation, and generate fuel cell power generation using hydrogen as fuel when necessary. Do.

  In such a hydrogen power storage system, hydrogen production becomes an endothermic reaction, and a power generation reaction becomes an exothermic reaction. Therefore, the hydrogen power storage system can be made highly efficient by supplying heat to the electrochemical device during hydrogen production and extracting heat from the electrochemical device during the power generation reaction. In such a case, it is necessary to provide heat exchange means in the electrochemical device.

  However, when heat exchange means is simply provided at both ends in the stacking direction of a plurality of electrochemical cells, the temperature difference between the center and both ends in the stacking direction becomes large, and the heat exchange efficiency does not necessarily increase. In particular, when heat exchange means are provided at both ends in the stacking direction of a large number of electrochemical cells, the heat exchange efficiency does not increase. In addition, from the viewpoint of suppressing the leakage of the reaction gas, it is preferable to provide a sealing material so as to cover these side surfaces in addition to between the electrochemical cell and the separator. When the sealing material is continuously provided so as to cover the entire side surface portion, the sealing material is likely to be damaged due to a difference in thermal expansion and displacement of individual components.

  The problem to be solved by the present invention is to provide a solid oxide electrochemical cell stack structure and a hydrogen power storage system that can improve heat exchange efficiency and can also prevent damage to a sealing material provided on a side surface portion. It is.

  The solid oxide electrochemical cell stack structure according to the embodiment includes a plurality of cell stacks and a flat plate heat exchanger disposed between the cell stacks. Each cell stack is formed by laminating a plurality of planar solid oxide electrochemical cells.

  According to the present invention, heat exchange efficiency is improved, and damage to the sealing material provided on the side surface portion can be suppressed.

The figure which shows typically an example of the laminated structure of a solid oxide type electrochemical cell stack structure. The figure which shows typically the other laminated structure of a solid oxide type electrochemical cell stack structure. The figure which shows typically the laminated structure of the solid oxide type electrochemical cell stack structure which has a flat heat exchanger in the one end part of the lamination direction. The figure which shows typically the laminated structure of the solid oxide type electrochemical cell stack structure which has a flat heat exchanger in the both ends of the lamination direction. The exploded sectional view showing an example of the lamination unit which has a solid oxide type electrochemical cell. Sectional drawing which shows an example of the electrochemical cell provided with the edge part cover. Sectional drawing which shows an example of a flat heat exchanger. The figure which shows typically an example of the lamination | stacking method of the cell stack and flat plate heat exchanger via metal foil. The figure which shows typically an example of the solid oxide type electrochemical cell stack structure which has a side part sealing material. The block diagram which shows an example of a hydrogen power storage system.

  Hereinafter, embodiments of a solid oxide electrochemical cell stack structure and a hydrogen power storage system will be described in detail with reference to the drawings. In the following description, a solid oxide electrochemical cell stack structure is simply referred to as a structure.

FIG. 1 is a schematic diagram illustrating an example of a laminated structure of the structure according to the embodiment.
The structure 10 includes a plurality of cell stacks 11 and a flat plate heat exchanger 12 disposed between the cell stacks 11. Each cell stack 11 is configured by laminating a plurality of flat solid oxide electrochemical cells 13. The flat solid oxide electrochemical cell 13 is actually stacked through a separator or the like (not shown). In the following description, the flat solid oxide electrochemical cell 13 is simply referred to as an electrochemical cell 13.

  By disposing the flat plate heat exchanger 12 between the cell stacks 11, the temperature difference in the stacking direction can be reduced and the heat exchange efficiency can be improved. In particular, when a large number of electrochemical cells 13 are stacked as a whole of the structure 10, these electrochemical cells 13 are divided into two or more parts (cell stack 11), and a flat plate heat exchanger is interposed between them. By arranging 12, for example, the temperature difference in the laminating direction can be reduced and the heat exchange efficiency can be improved as compared with the case where flat plate heat exchangers are arranged only at both ends in the laminating direction.

  The structure 10 may have at least two cell stacks 11 and one flat plate heat exchanger 12 disposed between the cell stacks 11. For example, as shown in FIG. In addition, it is preferable to have three or more cell stacks 11 and a flat plate heat exchanger 12 between the cell stacks 11. Increasing the number of cell stacks 11 can further reduce the temperature difference in the stacking direction and improve the heat exchange efficiency.

  The upper limit of the number of cell stacks 11 is not necessarily limited, and can be appropriately selected in consideration of the number of all electrochemical cells 13 in the structure 10, temperature differences in the stacking direction, and the like. In general, when the number of cell stacks 11 decreases, the number of electrochemical cells 13 in each cell stack 11 increases, so that the temperature difference in the stacking direction increases. Therefore, according to the number of all the electrochemical cells 13 in the structure 10, etc., the number of the respective cell stacks 11 is determined so that the number of the electrochemical cells 13 in each of the cell stacks 11 is not excessively increased. Is preferred.

  The number of all electrochemical cells 13 in the structure 10 is not necessarily limited, but is preferably 9 or more, more preferably 15 or more, and further preferably 30 or more. The upper limit of the number of all electrochemical cells 13 in the structure 10 is not necessarily limited, but is preferably 100 or less.

  Each cell stack 11 is configured by stacking two or more electrochemical cells 13. By arranging the flat plate heat exchanger 12 between the cell stacks 11 as described above, it is possible to reduce the temperature difference in the stacking direction and improve the heat exchange efficiency.

  The number of electrochemical cells 13 in each cell stack 11 is not necessarily limited as long as it is 2 or more, but is preferably 3 or more, more preferably 4 or more, and even more preferably 5 or more. By increasing the number of electrochemical cells 13 in the cell stack 11, it is possible to reduce the number of cell stacks 11 and suppress an excessive increase in the number of flat plate heat exchangers 12.

  The upper limit of the number of electrochemical cells 13 in each cell stack 11 is not necessarily limited, but is preferably 20 or less, more preferably 15 or less, and more preferably 10 or less from the viewpoint of reducing the temperature difference in the stacking direction. Is more preferable. Note that the number of electrochemical cells 13 in each cell stack 11 is not necessarily constant, and may be the same or different.

  In the structure 10, the cell stack 11 in which a plurality of electrochemical cells 13 are stacked and the flat plate heat exchanger 12 do not necessarily have to be strictly stacked alternately. For example, the structure 10 may include a single electrochemical cell 13 that does not constitute the cell stack 11 in part. In this case, with respect to some flat plate heat exchangers 12, a single electrochemical cell 13 is disposed on one main surface or both main surfaces. The structure 10 can partially have a single electrochemical cell 13 as described above, but the number of single electrochemical cells 13 is preferably 10% or less of the number of all electrochemical cells 13. More preferably, the electrochemical cell 13 is not provided. That is, the structure 10 is more preferably composed of a cell stack 11 in which a plurality of electrochemical cells 13 are stacked and a flat plate heat exchanger 12.

  Further, the structure 10 may include a flat plate heat exchanger 12 that is not disposed between the cell stacks 11. For example, as shown in FIG. 3, the flat plate heat exchanger 12 may be disposed at one end portion in the stacking direction, or as shown in FIG. 4, the flat plate heat exchanger 12 is disposed at both end portions in the stacking direction. May be.

Next, a specific configuration of the electrochemical cell 13 will be described.
FIG. 5 is an exploded cross-sectional view showing an example of a laminated unit having the electrochemical cell 13.

  The electrochemical cell 13 obtains electric energy and water vapor by electrochemically reacting a reducing agent such as hydrogen and an oxidizing agent such as oxygen, or reduces water vapor etc. by electrolysis with one electrode. The other electrode releases oxygen ions.

  The electrochemical cell 13 has a flat plate shape, and has, for example, a fuel electrode 132, an electrolyte membrane 133, and an air electrode 134 in this order on one surface of a hydrogen electrode porous substrate 131 that is a support substrate. That is, the electrochemical cell 13 is mainly composed of an electrolyte membrane 133, an air electrode 134 provided on one main surface of the electrolyte membrane 133, and a fuel electrode 132 provided on the other main surface of the electrolyte membrane 133.

  The electrolyte membrane 133 is made of a solid oxide having electronic insulation and ion conductivity. In addition, the electrolyte membrane 133 is formed dense so that gas leakage can be substantially ignored. As a constituent material of the electrolyte membrane 133, a constituent material of an electrolyte membrane in a known solid oxide fuel cell (SOFC) can be used without particular limitation. For example, a ceramic material having ion conductivity such as a ceria-based oxide doped with samarium or gadolinium, a lanthanum galide-based oxide doped with strontium or magnesium, or a zirconia-based oxide containing scandium or yttrium can be given. In addition, the constituent material of the electrolyte membrane 133 is not limited to these. The thickness of the electrolyte membrane 133 is not necessarily limited, but is preferably 5 to 500 μm from the viewpoint of mechanical strength and power generation characteristics.

  As a constituent material of the fuel electrode 132, a constituent material of a fuel electrode in a known solid oxide fuel cell (SOFC) can be used without particular limitation. For example, a mixture of a metal catalyst and a powder made of a ceramic material having ion conductivity or a composite powder thereof can be used.

  Examples of the metal catalyst include materials that are stable in a reducing atmosphere such as nickel, iron, cobalt, and noble metals (platinum, ruthenium, palladium, etc.) and have hydrogen oxidation activity. Examples of the ceramic material having ion conductivity include those having a fluorite structure or a perovskite structure. Examples of those having a fluorite structure include ceria-based oxides doped with samarium or gadolinium, zirconia-based oxides containing scandium or yttrium, and the like. Examples of those having a perovskite structure include lanthanum galade oxides doped with strontium and magnesium. The ceramic materials can be used alone or in combination of two or more. In addition, the fuel electrode 132 may be a single metal catalyst. The thickness of the fuel electrode 132 is not necessarily limited, but is preferably 10 to 1000 μm from the viewpoint of mechanical strength and power generation characteristics.

As a constituent material of the air electrode 134, a constituent material of the air electrode in a known solid oxide fuel cell (SOFC) can be used without particular limitation. For example, a metal oxide such as cobalt, iron, nickel, chromium, or manganese having a perovskite structure can be used. Specifically, (Sm, Sr) CoO ₃ , (La, Sr) MnO ₃ , (La, Sr) CoO ₃ , (La, Sr) (Fe, Co) O ₃ , (La, Sr) (Fe, Co, Ni) O _{3 and the} like. The ceramic materials can be used alone or in combination of two or more. The thickness of the air electrode 134 is not necessarily limited, but is preferably 10 to 1000 μm from the viewpoint of mechanical strength and power generation characteristics.

  For example, a frame-shaped cell holder 14 is provided around the electrochemical cell 13. In addition, separators 16 are disposed on both sides of the electrochemical cell 13 in the stacking direction via current collectors 15. A portion of the electrochemical cell 13, the cell holder 14, the pair of current collectors 15, and the pair of separators 16 constitutes one laminated unit 20, and a plurality of such laminated units 20 are laminated to form a cell stack. 11 is configured.

  The cell holder 14 is provided for supporting the electrochemical cell 13 and the like. The constituent material of the cell holder 14 is preferably a stable material that does not react with the reaction gas or peripheral members during operation, and for example, metal, glass, ceramics, and the like are preferable. The thickness of the cell holder 14 is preferably substantially the same as the thickness of the electrochemical cell 13.

  Although not shown, it is preferable to provide a filler between the electrochemical cell 13 and the cell holder 14. By providing a filler between the electrochemical cell 13 and the cell holder 14, it is possible to suppress a cross leak in which a reaction gas leaks from between the electrochemical cell 13 and the cell holder 14. As the filler, glass is preferable, and from the viewpoint of long-term durability, high melting point crystallized glass that is solid at 800 ° C. or lower is preferable. Examples of the filler include those containing such glass and at least one inorganic powder selected from ceramics and glass that does not react with the glass and peripheral members at the operating temperature and does not melt or soften. Formation of the filler between the electrochemical cell 13 and the cell holder 14 is performed, for example, by applying a paste containing the above components and setting the operating temperature or a temperature exceeding the operating temperature.

  The current collector 15 is disposed between the electrochemical cell 13 and the separator 16. The current collector 15 disposed between the fuel electrode 132 and the separator 16 on the fuel electrode side is preferably a porous body made of a metal such as nickel, silver, or platinum. The current collector 15 disposed between the air electrode 134 and the separator 16 on the air electrode side is, for example, a general metal such as nickel or stainless steel subjected to an oxidation-resistant surface treatment, or gold, silver, or A porous body composed of a metal having oxidation resistance such as platinum is preferred.

  The separator 16 is disposed on both sides of the electrochemical cell 13. That is, the electrochemical cell 13 is stacked on another electrochemical cell 13 or the flat plate heat exchanger 12 via the separator 16. A gas supply groove 161 is provided on the surface of the separator 16 facing the electrochemical cell 13. For example, a plurality of gas supply grooves 161 are linearly provided. The reaction gas is supplied to the electrochemical cell 13 through such a gas supply groove 161.

  Further, the top portion between the gas supply grooves 161 is in close contact with and electrically connected to the electrochemical cell 13 via the current collector 15, and the power supply to the electrochemical cell 13 or the power extraction from the electrochemical cell 13 is performed. Is done. The constituent material of the separator 16 is preferably a stable material that has conductivity and does not react with the reaction gas or peripheral members during operation. Although not shown, the separator 16 may have a gas manifold that supplies a reactive gas to the electrochemical cell 13 and discharges the reactive gas from the electrochemical cell 13.

  Although the electrochemical cell 13, the current collector 15 and the separator 16 are not shown in close contact with each other, for example, a plurality of holes are provided around these members so as to penetrate them in the stacking direction. This is done by inserting bolts into the parts and tightening in the stacking direction. At this time, when the separator 16 has a gas manifold as described above, the hole and the gas manifold may be integrated.

  An interlayer sealing material 17 is preferably provided between the cell holder 14 and the separator 16 in order to ensure airtightness. The interlayer sealing material 17 is preferably provided on the entire circumferential direction between the cell holder 14 and the separator 16. As the interlayer sealing material 17, glass is preferable, and high melting point crystallized glass that is solid at 800 ° C. or lower is particularly preferable from the viewpoint of long-term durability. Examples of the filler include those containing such glass and at least one inorganic powder selected from ceramics and glass that does not react with the glass and peripheral members at the operating temperature and does not melt or soften. Formation of the interlayer sealing material 1 between the cell holder 14 and the separator 16 is performed, for example, by applying a paste containing the above-mentioned components to an operating temperature or a temperature exceeding this.

  Although not shown, a groove for sealing material for storing the interlayer sealing material 17 is provided at a position where the interlayer sealing material 17 is provided in the cell holder 14 or the separator 16 in order to ensure adhesion by the interlayer sealing material 17. It is preferable. Further, the separator 16 has a groove cover 162 that covers at least the gas supply groove 161 in which the interlayer seal material 17 is disposed from the viewpoint of improving the adhesion and airtightness by smoothing the contact surface with the interlayer seal material 17. It is preferable to have.

  The width of the interlayer sealing material 17 is not necessarily limited as long as the airtightness between the cell holder 14 and the separator 16 can be secured, but is preferably about the same as the width of the cell holder 14. By setting the width of the sealing material 17 to be approximately the same as the width of the cell holder 14, good airtightness can be obtained.

When the size of the air electrode 134 is smaller than the size of the electrolyte membrane 133, the electrolyte membrane 133 is exposed around the air electrode 134 with a certain width. That is, a dense layer that does not participate in the reaction is exposed around the air electrode 134. In this case, the width (w ₁ ) of the sealing material 17 on the air electrode 134 side with respect to the electrolyte membrane 133 is equal to or larger than the width (w ₂ ) of the cell holder 14 and is dense with the width (w ₂ ) of the cell holder 14. Airtightness is further improved by setting the width (w ₃ ) or less (w ₂ ≦ w ₁ ≦ w ₂ + w ₃ ) of the layer width (w ₃ ).

  The electrochemical cell 13, cell holder 14, current collector 15 and interlayer seal material 17 preferably satisfy the following conditions from the viewpoint of improving airtightness and electrical contact. That is, a pair of electrochemical cells 13 (hydrogen electrode porous substrate 141, hydrogen electrode 142, electrolyte membrane 143, and oxygen electrode 144) and a pair disposed on both sides in the stacking direction in the state of operation of the structure 10. It is preferable that the total thickness of the current collectors 15 and the total thickness of the cell holder 14 and the pair of interlayer seal members 17 are substantially the same.

  Further, it is preferable that at least one selected from the current collector 15 and the interlayer seal material 17 is contracted according to the tightening pressure at the time of assembling the structure 10 to provide a certain degree of robustness with respect to ensuring airtightness and electrical contact. . Examples of such a current collector 15 include gold, silver mesh or felt, or a material obtained by stacking punching metal so as to have an appropriate thickness. The current collector 15 is preferably made of a material that expands or stretches during operation from the viewpoint of reducing contact resistance. As such a material, for example, a paste of a metal similar to an electrode or a metal having oxidation resistance (for example, gold, silver, etc.) and a foamable material (shirasu balloon, pearlite, fly ash, etc.) are mixed. Things. 1-20 mass% is preferable in the whole material, and, as for the mixing ratio of the substance which has foamability, 5-10 mass% is more preferable.

  As shown in FIG. 6, an end cover 18 that covers the upper and lower surfaces and the three sides of the end of the electrochemical cell 13 can be provided between the electrochemical cell 13 and the cell holder 14. By adjusting the smoothness and thickness uniformity of the end portion of the end cover 18 more strictly than the electrochemical cell 13, the influence of the smoothness and thickness of the end portion of the electrochemical cell 13 can be suppressed, and more High robustness can be given. The constituent material of the end cover 18 is preferably a stable material that does not react with the reaction gas or the peripheral member during operation, like the constituent material of the cell holder 14, and for example, metal, glass, ceramics and the like are preferable.

  A filler 19 is preferably provided between the electrochemical cell 13 and the end cover 18. By providing the filler 21 between them, cross leak can be suppressed. Although not shown, it is preferable to provide a filler between the cell holder 14 and the end cover 18. By providing a filler between the cell holder 14 and the end cover 18, cross leak can be further suppressed.

  The filler 19 provided between the electrochemical cell 13 and the end cover 18 and the filler provided between the cell holder 14 and the end cover 18 are preferably glass, and particularly 800 from the viewpoint of long-term durability. High melting point crystallized glass that is solid at a temperature of ℃ or lower is preferred. Examples of the filler include those containing such glass and at least one inorganic powder selected from ceramics and glass that does not react with the glass and peripheral members at the operating temperature and does not melt or soften. The filler is formed between the electrochemical cell 13 and the end cover 18 and between the cell holder 14 and the end cover 18, for example, by applying a paste containing the above components and operating temperature or a temperature exceeding this. This is done.

  The flat plate heat exchanger 12 has a large heat transfer area with a heat transport medium such as nitrogen gas from the viewpoint of efficiently exchanging heat at a limited contact surface with the cell stack 11 to reduce the size of the structure 10. It preferably has a structure. As the flat plate heat exchanger 12, for example, one having a tubular flow path 121 for a heat transport medium as shown in FIG. 7 is preferable. The cross-sectional shape of the channel 121 is not necessarily limited as long as heat exchange can be performed, and may be a circular shape, a quadrangular shape, or the like. Moreover, the planar shape of the flow path 121 is not necessarily limited as long as heat exchange can be performed, and can be linear, meandering, or the like, and the number and arrangement thereof can be determined as appropriate. Such a flow path 121 is preferably formed of a metal material such as stainless steel by an electrochemical method such as etching because fine processing is easy.

  The cell stack 11 and the flat plate heat exchanger 12 may be directly laminated, or may be laminated via a metal foil 21 such as a metal gasket as shown in FIG. By laminating via the metal foil 21, the thermal resistance between the two can be reduced by plastic deformation of the metal foil 21, and the deformation tolerance can be improved to reduce the stress that leads to a decrease in the airtightness of the cell stack 11. The constituent material of the metal foil 21 is preferably stainless steel or the like. The thickness of the metal foil 21 is preferably 0.05 to 0.1 mm.

  As shown in FIG. 9, it is preferable to provide a side surface sealing material 22 on the side surface of each cell stack 11 so as to cover the side surface of each cell stack 11. By providing the side surface sealing material 22, the airtightness can be further improved. Further, by providing the side surface sealing material 22 for each cell stack 11, for example, compared to the case where the cell stack 11 is continuously provided on the side surfaces of all the cell stacks 11, the continuous region is made smaller. Damage can be suppressed by reducing the influence of differences in thermal expansion and misalignment of the parts. Furthermore, since the number of layers of the stack unit 20 in each cell stack 11 is smaller than the number of layers of the stack unit 20 in the structure 10, the side surface seal 22 is provided for each cell stack 11, thereby The operation of providing the material 22 becomes easy.

  The side surface sealing material 22 is preferably provided so as to cover the side surface portions of all the stacked units 20 included in each cell stack 11. For example, in the case of the stacked unit 20 in which the electrochemical cell 13 is disposed so as to be surrounded by the cell holder 14 between the pair of separators 16, it straddles the side surface portion of the pair of separators 16 and the side surface portion of the cell holder 14. It is preferable to provide the side surface sealing material 22 as described above, and it is preferable that the side surface sealing material 22 is provided so as to straddle the side surface portions of other adjacent stacked units 20 in the same cell stack 11.

  In addition, when the hole for the supply or discharge | emission of reaction gas etc. is provided in the side part of the separator 16, the side part sealing material 22 is provided so that this hole etc. may be removed. Moreover, the formation range of the side part sealing material 22 is not necessarily limited only to the side part of the cell stack 11, and may be formed in a part of side part of the adjacent flat plate heat exchanger 12.

  As the side part sealing material 22, glass is preferable, and high melting point crystallized glass that is solid at 800 ° C. or lower is particularly preferable from the viewpoint of long-term durability. Examples of the filler include those containing such glass and at least one inorganic powder selected from ceramics and glass that does not react with the glass and peripheral members at the operating temperature and does not melt or soften. Formation of the side part sealing material 22 to a side part is performed by apply | coating the paste containing the said component and setting it as operating temperature or the temperature beyond this, for example.

  Although the structure 10 has been described above, the structure 10 may use an inorganic gasket instead of the interlayer sealing material 17 or together with the interlayer sealing material 17. Examples of the inorganic gasket include those having a frame shape substantially similar to that of the interlayer sealing material 17. Examples of the inorganic gasket include a material containing vermiculite and the like and formed into a sheet shape.

  When an inorganic gasket is used instead of the interlayer sealing material 17, it is disposed between the cell holder 14 and the separator 16 instead of the interlayer sealing material 17. Further, when an inorganic gasket is used together with the interlayer sealing material 17, the inorganic gasket is disposed between the interlayer sealing material 17 and the separator 16. When an inorganic gasket is used, disassembly of the structure 10 (lamination unit 20) after assembly is facilitated. In particular, the combined use of the interlayer sealing material 17 and the inorganic gasket facilitates disassembly of the structure 10 (lamination unit 20) after assembly, and improves airtightness and electrical insulation.

  The structure 10 is equipped with an external manifold or the like as necessary, and is at least one selected from a solid oxide fuel cell (SOFC) and a solid oxide electrolysis cell (SOEC). It is suitably used as an electrochemical device that functions as For example, the electrochemical device may function only as SOFC or SOEC, or may function as SOFC in some cases and function as SOEC in other times. In addition, the electrochemical device may be one in which all the cell stacks 11 function simultaneously as SOFC or SOEC, or a part of the cell stacks 11 function as SOFC and at the same time other cell stacks 11 function as SOEC. Good.

  As an electrochemical apparatus, what is used for a hydrogen production system is preferable, and what is used for a hydrogen power storage system is more preferable. Hydrogen power storage systems, for example, produce and store hydrogen by electrolysis of water using renewable energy with large output fluctuations such as solar power and wind power generation, and generate fuel cell power generation using hydrogen as fuel when necessary. Do. In the hydrogen power storage system, for example, the electrochemical device functions as SOEC to produce hydrogen by electrolysis of water, and the electrochemical device functions as SOFC to generate fuel cell power using hydrogen. In the hydrogen power storage system, hydrogen production becomes an endothermic reaction, and the power generation reaction becomes an exothermic reaction. Therefore, the hydrogen power storage system can be made highly efficient by supplying heat to the electrochemical device functioning as the SOEC and extracting the heat from the electrochemical device functioning as the SOFC. By applying the structure 10 to such an electrochemical device, the hydrogen power storage system can be made more efficient. Even in the hydrogen production system, it is possible to increase the efficiency by effectively supplying the heat of the endothermic reaction.

FIG. 10 is a configuration diagram illustrating an example of a hydrogen power storage system.
The hydrogen power storage system 30 includes an electrochemical device 31, a hydrogen storage tank 32, and pipes 33 and 34 connecting them.

  The electrochemical device 31 has the structure 10. The electrochemical device 31 has both SOFC and SOEC functions. That is, the electrochemical device 31 is a power / hydrogen conversion device that can operate in a power generation mode and an electrolysis mode.

  The hydrogen storage tank 32 stores hydrogen produced by the electrochemical device 31 and supplies hydrogen to the fuel cell power generation of the electrochemical device 31 as necessary. Hydrogen is transported from the electrochemical device 31 to the hydrogen storage tank 32 through a pipe 33. Further, hydrogen is transported from the hydrogen storage tank 32 to the electrochemical device 31 through a pipe 34.

  In the hydrogen power storage system 30, for example, hydrogen is produced by electrolysis of water by an electrochemical device 31 using renewable energy having a large output fluctuation such as sunlight or wind power generation. At this time, the production efficiency of hydrogen can be improved by supplying heat through the flat plate heat exchanger 12 of the electrochemical device 31. On the other hand, at the time of fuel cell power generation, heat is taken out through the flat plate heat exchanger 12 of the electrochemical device 31 and stored in another device or the like, or the heat can be used effectively.

  As mentioned above, although embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of 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.

  DESCRIPTION OF SYMBOLS 10 ... Solid oxide type electrochemical cell stack structure, 11 ... Cell stack, 12 ... Flat plate heat exchanger, 13 ... Flat plate solid oxide type electrochemical cell, 14 ... Cell holder, 15 ... Current collector, 16 ... Separator, 17 ... interlayer seal, 18 ... end cover, 20 ... lamination unit, 21 ... metal foil, 22 ... side seal, 30 ... hydrogen power storage system, 31 ... electrochemical device, 32 ... hydrogen storage tank, 33, 34 ... piping, 121 ... flow path, 131 ... hydrogen electrode porous substrate, 132 ... fuel electrode, 133 ... electrolyte membrane, 134 ... air electrode

Claims (10)

A plurality of cell stacks in which a plurality of planar solid oxide electrochemical cells are stacked;
A solid oxide electrochemical cell stack structure comprising: a flat plate heat exchanger disposed between the cell stacks. The solid oxide electrochemical cell stack structure according to claim 1,
A solid oxide electrochemical cell stack structure in which three or more cell stacks are provided and the flat plate heat exchanger is disposed between the cell stacks. The solid oxide electrochemical cell stack structure according to claim 1 or 2,
The cell stack is a solid oxide electrochemical cell stack structure having 20 or less flat plate solid oxide electrochemical cells. The solid oxide electrochemical cell stack structure according to any one of claims 1 to 3,
The cell stack is a solid oxide electrochemical cell stack structure in which a side surface portion is covered with a side surface sealing material containing glass independently of each other. The solid oxide electrochemical cell stack structure according to claim 4,
The glass is a solid oxide electrochemical cell stack structure which is a high melting point crystallized glass which is solid at 800 ° C. or lower. The solid oxide electrochemical cell stack structure according to any one of claims 1 to 5,
A solid oxide electrochemical cell stack structure in which the plate heat exchanger and the cell stack are directly laminated. The solid oxide electrochemical cell stack structure according to any one of claims 1 to 5,
A solid oxide electrochemical cell stack structure in which the flat plate heat exchanger and the cell stack are laminated via a metal foil. The solid oxide electrochemical cell stack structure according to claim 7,
The metal foil is a solid oxide electrochemical cell stack structure made of stainless steel. The solid oxide electrochemical cell stack structure according to any one of claims 1 to 8,
The flat plate heat exchanger is a solid oxide electrochemical cell stack structure having a heat transport medium channel formed therein by an electrochemical method.   The solid oxide electrochemical cell stack structure according to any one of claims 1 to 9 functions as at least one selected from a solid oxide fuel cell (SOFC) and a solid oxide electrolytic cell (SOEC). Hydrogen power storage system.

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