JP2015183252A - Cell stack and electrolytic module, and electrolytic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cell stack, an electrolytic module, and an electrolytic apparatus, in each of which peeling of a coating layer from a conductive substrate and diffusion of Cr to an electrode layer from the conductive substrate can be reduced.SOLUTION: A conductive member 4 is formed by coating the surface of a current collecting substrate 41 made of an alloy containing Cr with a coating layer 43 made of ceramics, and includes a first conductive piece 4a joined to a first fuel cell 3s and a second conductive piece 4b joined to a second fuel cell 3. A coating layer 43 on a first principal plane 4g on the side where the first and second conductive pieces 4a, 4b are joined to the fuel cell 3 is thicker than a coating layer 43 on a second principal plane 4j opposite to the first principal plane 4g. The first principal plane 4g of the first conductive piece 4a and the second conductive piece 4b, and the side plane formed continuously from the first principal plane 4g are joined to the fuel cell 3 by a conductive joint member 13.

Description

  The present invention relates to a cell stack, an electrolysis module, and an electrolysis apparatus in which a plurality of electrolysis cells are electrically connected using a conductive member having a conductive substrate covered with a coating layer.

  In recent years, as a next-generation energy, using a fuel gas (hydrogen-containing gas) and an oxygen-containing gas (air or the like), for example, a solid oxide fuel cell that generates power at a high temperature of 600 to 1000 ° C., and A cell stack in which a plurality of fuel cells are electrically connected in series via a current collecting member (conductive member) is known (see, for example, Patent Document 1).

  In this Patent Document 1, since heat resistance is required as a current collecting member, the surface of a current collecting substrate (conductive substrate) made of an alloy containing Cr is covered with a coating layer made of ceramics that reduces Cr diffusion. Things are used. The current collecting substrate is cut into a predetermined shape by a shearing force by pressing, and thereafter, the surface of the current collecting substrate is coated with a coating layer by dipping, sputtering, or the like, thereby constituting a current collecting member.

JP 2005-339904 A

  However, conventionally, no consideration has been given to the thickness of the coating layer covering the current collector substrate between the portion joined to the fuel cell and the portion that is not, so that the coating layer is peeled off or collected from the current collector substrate. There was a risk of Cr diffusion from the electric substrate.

  An object of the present invention is to provide a cell stack, an electrolytic module, and an electrolytic device that can reduce peeling of a coating layer from a conductive substrate and diffusion of Cr into an electrode layer.

  The cell stack of the present invention is a cell in which electrolytic cells and conductive members are alternately arranged, the electrolytic cells and the conductive members are bonded with a conductive bonding material, and a plurality of the electrolytic cells are electrically connected. A first conductive piece that is a stack, the conductive member is formed by coating a conductive substrate made of an alloy containing Cr with a coating layer made of ceramics, and is joined to the first electrolysis cell; And a thickness of the coating layer on the first main surface of the first conductive piece and the second conductive piece on the side to be joined to the electrolytic cell. It is thicker than the thickness of the coating layer on the second main surface opposite to the one main surface, and is formed continuously from the first main surface and the first main surface of the first conductive piece and the second conductive piece. The side surface of the electrolysis cell is made of the conductive bonding material. The combined wherein the are.

  The electrolytic module of the present invention is characterized in that the cell stack is stored in a storage container.

  Furthermore, the electrolysis apparatus of the present invention is characterized in that the electrolysis module and an auxiliary machine for operating the electrolysis module are housed in an outer case.

  According to the cell stack of the present invention, it is possible to reduce the diffusion of Cr from the conductive substrate to the electrolytic cell, and to reduce the peeling of the coating layer on the first main surface and the second main surface. Therefore, long-term reliability can be improved by using such a cell stack for an electrolytic module and an electrolytic apparatus.

The cell stack apparatus is shown, (a) is a side view, (b) is an enlarged cross-sectional view showing a part of (a). It is a perspective view which extracts and shows the current collection member of FIG. (A) is the side view seen from the AA line of the current collection member shown in FIG. 2, (b) is the BB sectional drawing of the current collection member shown in FIG. (A) is sectional drawing which expands and shows the conductive piece of the current collection member shown in FIG.3 (b), (b) is CC sectional view taken on the line of (a). It is explanatory drawing which shows the first half of the manufacturing process of a current collection member. It is explanatory drawing which shows the second half of the manufacturing process of a current collection member. It is a longitudinal cross-sectional view which shows the joining state of the fuel cell and current collection member in the cell stack of FIG. It is an external appearance perspective view which decomposes | disassembles and shows the fuel cell module formed by accommodating the cell stack of FIG. 1 in a storage container. It is a perspective view which shows the fuel cell apparatus which accommodates a fuel cell module in an exterior case.

  FIG. 1 shows a cell stack device. This cell stack device 1 has a plurality of solid oxide fuel cells 3 which are a kind of electrolytic cells. The plurality of fuel cells 3 each have a gas flow path 12 therein, and have a pair of opposed main surfaces as a whole, a columnar conductive support 7, and one main support of the conductive support 7. On the surface, there is provided a power generation unit in which a fuel electrode layer 8 as an inner electrode layer, a solid electrolyte layer 9, and an oxygen electrode layer 10 as an outer electrode layer are arranged in this order. An interconnector layer 11 is disposed on the other main surface of the conductive support 7 to constitute a columnar (hollow flat plate) fuel cell 3.

  A plurality of fuel cells 3 are arranged in a row, and current collecting members (conductive members) 4 are arranged between adjacent fuel cells 3. As will be described in detail later, the fuel cell 3 and the current collecting member 4 are joined via a conductive bonding material 13, whereby a plurality of fuel cells 3 are joined via the current collecting member 4. The cell stack 2 is configured by electrical and mechanical joining.

  Also, a P-type semiconductor layer (not shown) can be provided on the outer surface of the interconnector layer 11. By connecting the current collecting member 4 to the interconnector layer 11 via the P-type semiconductor layer, the contact between them becomes an ohmic contact, and the potential drop can be reduced.

  The lower end portion of each fuel cell 3 constituting the cell stack 2 is fixed to the opening of the gas tank 6 with a sealing material 14 such as glass, whereby the fuel gas in the gas tank 6 is transferred to the fuel cell 3. Can be supplied to the fuel electrode layer 8 of the fuel cell 3 via the gas flow path 12 provided inside the fuel cell.

In the cell stack device 1 shown in FIG. 1, a hydrogen-containing gas flows as a fuel gas inside the gas flow path 12 of the fuel cell 3 and is disposed outside the fuel cell 3, particularly between the fuel cells 3. The oxygen-containing gas (air) flows through the internal space S of the current collecting member 4. As a result, the fuel gas is supplied from the gas tank 6 to the fuel electrode layer 8 and the oxygen-containing gas is supplied to the oxygen electrode layer 10, thereby generating power in the fuel cell 3.

  The cell stack device 1 is configured by arranging an elastically deformable conductive holding member 5 so as to hold the cell stack 2 from both ends in the arrangement direction x of the fuel cells 3, and a lower end of the holding member 5. The part is fixed to the gas tank 6. The sandwiching member 5 has a flat plate portion 5a provided so as to be positioned at both ends of the cell stack 2, and a shape extending outward along the arrangement direction x of the fuel cells 3, and the cell stack 2 (fuel cell) And a current extraction part 5b for extracting a current generated by the power generation of 3).

  Below, each member which comprises the fuel cell 3 of FIG. 1 is demonstrated.

As the fuel electrode layer 8, generally known ones can be used, and porous conductive ceramics such as ZrO ₂ (referred to as stabilized zirconia) in which a rare earth element oxide is dissolved, Ni and / or Or it can comprise with NiO.

The solid electrolyte layer 9 has a function as an electrolyte that bridges electrons between the electrodes, and at the same time, has to have a gas barrier property in order to prevent leakage between the fuel gas and the oxygen-containing gas. 3 to 15 mol% of a rare earth element oxide is formed of ZrO ₂ as a solid solution. In addition, as long as it has the said characteristic, you may comprise using another material etc.

The oxygen electrode layer 10 is not particularly limited as long as it is generally used. For example, the oxygen electrode layer 10 can be made of a conductive ceramic made of a so-called ABO ₃ type perovskite complex oxide. The oxygen electrode layer 10 needs to have gas permeability, and can have an open porosity of 20% or more, particularly 30 to 50%. As the oxygen electrode layer 10, for example, at least one of lanthanum manganite (LaSrMnO ₃ ), lanthanum ferrite (LaSrFeO ₃ ), lanthanum cobaltite (LaSrCoO ₃ ) and the like in which Mn, Fe, Co, etc. exist at the B site is used. Can do.

The interconnector layer 11 can be made of conductive ceramics, but needs to have reduction resistance and oxidation resistance because it comes in contact with a fuel gas (hydrogen-containing gas) and an oxygen-containing gas (air, etc.). For example, lanthanum chromite (LaCrO ₃ ) can be used. The interconnector layer 11 is dense in order to prevent leakage of the fuel gas flowing through the plurality of gas flow paths 12 existing in the conductive support 7 and the oxygen-containing gas flowing outside the conductive support 7. The relative density is preferably 93% or more, particularly 95% or more.

  The conductive support 7 needs to be gas permeable in order to allow the fuel gas to pass to the fuel electrode layer 8 and further to be conductive in order to collect current through the interconnector layer 11. Is done. Therefore, as the conductive support 7, it is necessary to use a material that satisfies this requirement. For example, conductive ceramics or cermet can be used.

  When the fuel cell 3 is manufactured, when the conductive support 7 is manufactured by co-firing with the fuel electrode layer 8 or the solid electrolyte layer 9, the conductive battery 7 is electrically conductive from the iron group metal component and the specific rare earth element oxide. The support 7 can be configured. Further, the conductive support 7 preferably has an open porosity of 30% or more, particularly 35 to 50% in order to have gas permeability, and the conductivity is 50 S / cm or more, Furthermore, it may be 300 S / cm or more and 440 S / cm or more.

Furthermore, as a P-type semiconductor layer (not shown), a layer made of a transition metal perovskite oxide can be exemplified. Specifically, those having higher electron conductivity than lanthanum chromite constituting the interconnector layer 11, for example, lanthanum manganite (LaSrMnO ₃ ), lanthanum ferrite (LaSrFeO ₃ ) in which Mn, Fe, Co, etc. exist at the B site. P-type semiconductor ceramics made of at least one kind such as lanthanum cobaltite (LaSrCoO ₃ ) can be used. In general, the thickness of such a P-type semiconductor layer is preferably in the range of 30 to 100 μm.

  The conductive joining material 13 joins the fuel cell 3 and the current collecting member 4 and can be configured using conductive ceramics or the like. As the conductive ceramic, one similar to that constituting the oxygen electrode layer 10 can be used. When the conductive ceramic is composed of the same components as the oxygen electrode layer 10, the bonding strength between the oxygen electrode layer 10 and the conductive bonding material 13 is high. Since it becomes high, it is preferable.

Specifically, LaSrCoFeO ₃ , LaSrMnO ₃ , LaSrCoO ₃ or the like can be used as the conductive bonding material 13. These materials may be produced using a single material, or the conductive bonding material 13 may be produced by combining two or more kinds.

  Further, the conductive bonding material 13 may be made of different materials having different particle diameters, or may be made of different materials having the same particle diameter. Furthermore, it may be composed of the same material having different particle diameters, or may be composed of the same material having the same particle diameter. When different particle diameters are used, it is preferable that the fine particle diameter is 0.1 to 0.5 μm and the coarse particle diameter is 1.0 to 3.0 μm. Moreover, when comprising the electroconductive joining material 13 with the same particle size, it is preferable that a particle size shall be 0.5-3 micrometers.

  Thus, by producing the conductive bonding material 13 using materials having different particle sizes, coarse particles having a large particle size improve the strength of the conductive bonding material 13, and fine particles having a small particle size are made conductive. The sinterability of the bonding material 13 can be improved.

  Next, the current collecting member 4 will be described with reference to FIGS. The current collecting member 4 shown in FIG. 2 includes a plurality of first conductive pieces (first conductive pieces) 4a joined to one adjacent fuel cell 3 and a plurality joined to the other adjacent fuel cell 3. Second conductive piece (second conductive piece) 4b, a plurality of first current collecting pieces 4a and a first connecting portion 4c for connecting one ends of the plurality of second current collecting pieces 4b, and a plurality of first current collecting pieces The piece 4a and the second connecting portion 4d that connects the other ends of the plurality of second current collecting pieces 4b are used as a set of units. A plurality of sets of these units are connected in the longitudinal direction of the fuel battery cell 3 by the conductive connecting piece 4e. The first current collecting piece 4 a and the second current collecting piece 4 b are portions joined to the fuel cell 3. Further, a space S through which the oxygen-containing gas passes is defined between the first current collecting piece 4a and the second current collecting piece 4b.

  In the fuel cell 3, as described above, the portion where the fuel electrode layer 8 and the oxygen electrode layer 10 face each other through the solid electrolyte layer 9 is a portion that generates power. Therefore, in order to efficiently collect the current generated by the power generation unit of the fuel cell 3, the length of the current collecting member 4 along the longitudinal direction of the fuel cell 3 is the oxygen electrode layer in the fuel cell 3. It is preferable that the length is equal to or greater than 10 in the longitudinal direction. The structure of the current collecting member 4 is not limited to this.

  Since the current collecting member 4 is exposed to a high-temperature oxidizing atmosphere during the operation of the cell stack apparatus 1, a covering layer 43 is formed on the entire surface of the current collecting substrate (conductive substrate) 41, thereby collecting the current collecting member. Deterioration of the member 4 can be reduced. The thickness of the coating layer 43 is preferably 1 to 20 μm, particularly 1.5 to 5 μm. FIG. 4 shows a state in which the covering layer 43 is formed on the entire surface of the current collecting substrate 41, and oblique lines indicating a cross section of the current collecting substrate 41 are omitted.

Since the current collecting member 4 needs to have conductivity in a heat-resistant and high-temperature oxidizing atmosphere, the current collecting substrate 41 is made of an alloy containing Cr. In particular, since the current collecting member 4 is exposed to a high-temperature oxidizing atmosphere, the current collecting substrate 41 is made of an alloy containing Cr at a rate of 4 to 30% by mass. The current collecting substrate 41 can be made of, for example, a Fe—Cr alloy or a Ni—Cr alloy. The current collecting substrate 41 is a conductive substrate for high temperature (600 to 1000 ° C.).

  Further, in order to reduce the diffusion of Cr in the current collecting substrate 41 into the fuel cell 3, particularly the oxygen electrode layer 10, the coating layer 43 has a Zn oxide, or a perovskite complex oxide containing La and Sr. A thing etc. can be used. The coating layer 43 only needs to reduce the diffusion of Cr and may be other than the above materials.

  As shown in FIG. 3, the first current collecting piece 4 a and the second current collecting piece 4 b have a rectangular cross section and a first main surface 4 g (fuel) perpendicular to the arrangement direction x of the fuel cells 3. The second main surface of the surface opposite to the first side surface 4h, the second side surface 4i, and the first main surface 4g, which are parallel to the arrangement direction x of the fuel cells 3. 4j. In other words, the first main surface 4g, which is the surface facing the fuel cell 3, the first side surface 4h and the second side surface 4i adjacent to both sides of the first main surface 4g, and the first main surface 4g. 2 main surfaces 4j. The first side surface 4 h and the second side surface 4 i are side surfaces parallel to the thickness direction of the current collector substrate 41. The areas of the first main surface 4g and the second main surface 4j are sufficiently larger than the areas of the first side surface 4h and the second side surface 4i.

  And thickness t1 of the coating layer 43 in the 1st main surface 4g of the side joined to the fuel cell 3 of the 1st current collection piece 4a and the 2nd current collection piece 4b is the 2nd main main surface which opposes the 1st main surface 4g. The surface 4j is formed thicker than the thickness t2 of the coating layer 43. In particular, the thickness t1 of the covering layer 43 on the first main surface 4g is preferably 1.1 times or more, and further 1.2 times or more than the thickness t2 of the covering layer 43 on the second main surface 4j. On the other hand, from the viewpoint of suppressing the peeling of the coating layer 43, the thickness t1 is preferably not more than twice the thickness t2, and more preferably not more than 1.5 times. The thickness t2 of the coating layer 43 on the second main surface 4j is preferably 1 μm or more, and particularly 1 to 5 μm.

  Further, the thickness t1 of the coating layer 43 on the first main surface 4g on the side where the first current collecting piece 4a and the second current collecting piece 4b are joined to the fuel battery cell 3 is the same as that on the first side surface 4h and the second side surface 4i. The covering layer 43 is formed thicker than the thickness t3. Thereby, the diffusion of Cr from the first main surface 4g having a short distance and a large area with the fuel cell 3 can be reduced. Further, the thickness t3 of the coating layer 43 on the first side surface 4h and the second side surface 4i is the coating on the first main surface 4g on the side where the first current collecting piece 4a and the second current collecting piece 4b are joined to the fuel cell 3. Since the thickness is smaller than the thickness t1 of the layer 43, the peeling of the coating layer 43 can be reduced even when the conductive bonding material 13 does not cover the first side surface 4h and the second side surface 4i.

  The thickness of the coating layer 43 on the first side surface 4h and the second side surface 4i is desirably formed thicker than the thickness t2 of the coating layer 43 on the second main surface 4j. Thereby, the spreading | diffusion of Cr to the fuel cell via the electroconductive joining material 13 from the 1st side surface 4h and the 2nd side surface 4i can be reduced.

  The corners of the current collecting substrate 41 are rounded, and as shown in FIG. 3B, the curvature of the current collecting substrate 41 is the same as that of the first main surface 4g in the first current collecting piece 4a joined to the oxygen electrode layer 10. Corners formed by the first side surface 4h and the second side surface 4i (corners on the oxygen electrode layer 10 side) are formed by the second main surface 4j, the first side surface 4h, and the second side surface 4i (interconnector layer). Is set smaller than the corner portion on the 11 side. Since the curvature of the corner formed by the first main surface 4g, the first side surface 4h and the second side surface 4i is small, cracks and the like in the coating layer 43 can be suppressed even when the coating layer 43 made of ceramics is thick, and Cr It is possible to further suppress the diffusion of Cr into the oxygen electrode layer 10 which is greatly affected by poisoning.

  Further, in the second current collecting piece 4b joined to the interconnector layer 11, the curvature of the corner formed by the first main surface 4g, the first side surface 4h, and the second side surface 4i is the second main surface 4j and the second main surface 4j. It is set to be larger than the curvature of the corner formed by the first side surface 4h and the second side surface 4i.

  Next, a method for producing the current collecting member 4 will be described. As shown to Fig.5 (a), on the lower mold | type 19a1 of the press machine provided with the lower mold | type 19a1 and the upper mold | type 19b1, the plate-shaped thickness which made the shape of one rectangle 0.1-1 mm, for example A current collecting board 41 is placed. Thereafter, as shown in FIG. 5B, the upper mold 19b1 is lowered to form a slit extending in the width direction of the current collecting substrate 41 as shown in FIG. 5C. The upper die 19b1 having a shape for forming a slit is inserted into the hole of the lower die 19a1 in which the slit portion is cut out, and the slit is formed in the current collecting substrate 41 by a shearing force.

  And as shown in FIG.6 (d), by clamping between the lower mold | type 19a2 and the upper mold | type 19b2 which round the corner | angular part of the current collection board | substrate 41, by pressing the main surface side of the current collection board | substrate 41, As shown in FIG. 6E, the corners of the current collecting substrate 41 can be rounded, and the covering layer 43 can be easily formed on this portion. By adjusting the curvatures of the corners of the lower die 19a2 and the upper die 19b2, the curvature of the corners on the oxygen electrode layer 10 side of the current collecting substrate 41 in the first current collecting piece 4a is changed to the corner on the interconnector layer 11 side. It can be smaller than the curvature of the part.

  Thereafter, as shown in FIG. 6F, the current collecting member 4 can be formed by forming a coating layer 43 on the surface of the current collecting substrate 41 by sputtering, for example.

  5C and FIGS. 6D to 6F are cross-sectional views, but the oblique lines in the current collecting substrate 41 are omitted.

  In the sputtering, first, an evaporation source is arranged above the current collecting substrate 41 arranged so that the first main surface 4g of the first current collecting piece 4a is on the upper side, and a coating layer is formed on the surface of the current collecting substrate 41 Thereafter, the vapor deposition source is arranged above the current collecting substrate 41 arranged so that the first main surface 4g of the second current collecting piece 4b is on the upper side, and a coating layer is formed on the surface of the current collecting substrate 41 Then, a coating layer is formed on the surface of the current collecting substrate 41 with a predetermined thickness.

  Then, a plate-like mask for blocking sputtering is inserted into the space S between the first current collecting piece 4a and the second current collecting piece 4b of the current collecting substrate 41, and the first main piece of the first current collecting piece 4a is inserted. A vapor deposition source is arranged above the current collecting substrate 41 arranged so that the surface 4g is on the upper side, a coating layer is formed on the surface of the current collecting substrate 41, and then the first main piece of the second current collecting piece 4b is formed. A vapor deposition source is arranged above the current collecting substrate 41 arranged so that the surface 4 g is on the upper side, and a coating layer is formed on the surface of the current collecting substrate 41. Thereby, the thickness of the coating layer 43 on the first main surface 4g of the first current collecting piece 4a and the second current collecting piece 4b is larger than the thickness of the coating layer 43 on the second main surface 4j facing the first main surface 4g. Can also be formed thick.

  Next, the joining state of the current collecting member 4 and the fuel cell 3 by the conductive joining material 13 will be described with reference to FIG.

  As shown in FIG. 7, the current collecting member 4 and the fuel cell 3 are joined via a conductive joining material 13. That is, the current collecting member 4 and the fuel cell 3 are electrically and mechanically connected by the conductive bonding material 13. The conductive bonding material 13 is provided so as to cover the first main surface 4g, the first side surface 4h, and the second side surface 4i, and the conductive bonding material 13 located on the first side surface 4h and the second side surface 4i is respectively It is provided so as to increase toward the fuel cell 3 to be joined (so as to form a meniscus). Moreover, you may provide the electroconductive joining material 13 so that the 1st current collection piece 4a and the 2nd current collection piece 4b may be covered completely by coat | covering the perimeter of the current collection member 4. FIG.

  That is, in FIG. 7, the conductive bonding material 13 is arranged for bonding the fuel cell 3 and the current collecting member 4, and the oxygen electrode layer 10 is disposed on the oxygen electrode layer 10 side of the fuel cell 3. It is provided over the entire surface. A conductive bonding material 13 is provided over the entire surface of the interconnector layer 11 on the interconnector layer 11 side of the fuel cell 3. Alternatively, the current collector 4 and the fuel cell 3 may be joined by providing the conductive joining material 13 only on part of the oxygen electrode layer 10 or the interconnector layer 11.

  In order to reduce the diffusion of Cr, it is better that the thickness of the coating layer 43 is thick. However, since the surface of the current collector substrate 41 made of an alloy is covered with the coating layer 43 made of ceramics, the thickness of the coating layer 43 is thick. And tends to peel off from the surface of the current collecting substrate 41.

  On the other hand, in the present embodiment, the thickness t1 of the coating layer 43 on the first main surface 4g of the first current collecting piece 4a and the second current collecting piece 4b joined to the fuel cell 3 is the first main surface 4g. Is thicker than the thickness t2 of the coating layer 43 on the second main surface 4j opposite to the first main surface 4j, it is possible to reduce the diffusion of Cr from the current collecting substrate 41 to the fuel cell 3 and to reduce the first main surface 4g and the first main surface 4g. Since the first side surface 4h and the second side surface 4i formed continuously from the surface 4g are bonded to the fuel cell 3 by the conductive bonding material 13, the peeling of the coating layer 43 on the first main surface 4g is reduced. it can.

  Next, the fuel cell module 20 in which the cell stack device 1 is stored in the storage container 21 will be described with reference to FIG.

  A fuel cell module 20 shown in FIG. 8 includes a reformer 22 for reforming raw fuel such as natural gas or kerosene to generate fuel gas in order to obtain fuel gas used in the fuel cell 3. It is arranged above the cell stack 2. The fuel gas generated by the reformer 22 is supplied to the gas tank 6 through the gas flow pipe 23 and supplied to the gas flow path 12 provided inside the fuel battery cell 3 through the gas tank 6. .

  FIG. 8 shows a state in which a part (front and rear surfaces) of the storage container 21 is removed and the cell stack device 1 and the reformer 22 housed inside are taken out rearward. Here, in the fuel cell module 20 shown in FIG. 8, the cell stack device 1 can be slid and stored in the storage container 21.

  In addition, the oxygen-containing gas introduction member 24 provided inside the storage container 21 is disposed between the pair of cell stacks 2 juxtaposed in the gas tank 6 in FIG. 8, and the oxygen-containing gas flows into the fuel gas. Accordingly, the oxygen-containing gas is supplied to the lower end side of the fuel cell 3 so that the fuel cell 3 flows laterally from the lower end side toward the upper end side. The surplus fuel gas (fuel offgas) that has been discharged from the gas flow path 12 of the fuel cell 3 and was not used for power generation is burned above the upper end of the fuel cell 3, so that the temperature of the cell stack 2 is increased. Can be effectively increased, and the activation of the cell stack device 1 can be accelerated. In addition, the fuel gas that has not been used for power generation discharged from the gas flow path 12 of the fuel battery cell 3 is burned above the upper end of the fuel battery cell 3 to be disposed above the cell stack 2. The reformer 22 can be warmed. Thereby, the reforming reaction can be efficiently performed in the reformer 22.

  Next, a fuel cell device 25 in which the fuel cell module 20 and an auxiliary machine (not shown) for operating the fuel cell module 20 are housed in an outer case will be described with reference to FIG.

The fuel cell device 25 shown in FIG. 9 has a module housing chamber 29 in which the inside of an exterior case made up of a support column 26 and an exterior plate 27 is vertically divided by a partition plate 28 and the upper side thereof houses the above-described fuel cell module 20. The lower side is configured as an auxiliary equipment storage chamber 30 for storing auxiliary equipment for operating the fuel cell module 20. In addition, the auxiliary machine stored in the auxiliary machine storage chamber 30 is omitted.

  Further, the partition plate 28 is provided with an air circulation port 31 for flowing the air in the auxiliary machine storage chamber 30 to the module storage chamber 29 side, and a part of the exterior plate 27 constituting the module storage chamber 29 An exhaust port 32 for exhausting air in the module storage chamber 29 is provided.

  Although the present invention has been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and improvements can be made without departing from the scope of the present invention.

For example, in the above embodiment, a cell stack, a fuel cell module, and a fuel cell device using fuel cells have been described. However, the present invention is not limited to this, and water vapor and voltage are applied to an electrolytic cell to provide water vapor. It can also be applied to an electrolysis cell (SOEC) that generates hydrogen and oxygen (O ₂ ) by electrolyzing (water), a cell stack including the electrolysis cell, an electrolysis module, and an electrolysis apparatus.

First, on one side of the supporting substrate made of Ni and _Y 2 _{O 3,} the fuel electrode layer of Ni and _Y 2 _{O 3} is from _ZrO 2 and (YSZ) was dissolved, a solid electrolyte layer made of _{YSZ, La 0.6} A fuel cell shown in FIG. 1 was produced in which an oxygen electrode layer made of Sr _0.4 Co _0.2 Fe _0.8 O ₃ (LSCF) and an interconnector layer made of lanthanum chromite were formed on the other side.

  Thereafter, a current collecting member as shown in FIGS. 2 to 4 was formed on the surface of the current collecting substrate by a sputtering method with a coating layer made of ZnO. Of the first current collecting piece and the second current collecting piece of the current collecting member, the cut surfaces of 10 current collecting pieces were observed by SEM (scanning electron microscope: 500 times), and the thickness of the coating layer was confirmed. The thickness of the coating layer at the center of the first main surface 4g, the coating layer at the center of the second main surface 4j, the coating layer at the center of the first side surface 4h, and the thickness of the coating layer at the center of the second side surface 4i are measured. The average value was obtained.

  As for the thickness of the covering layer, the thickness of the first main surface 4g of the first current collecting piece 4a is 2.7 μm, the thickness of the second main surface 4j is 2.1 μm, and the thickness of the first side surface 4h and the second side surface 4i is The thickness of the first main surface 4g of the second current collecting piece 4b is 2.7 μm, the thickness of the second main surface 4j is 2.1 μm, the first side surface 4h, The thickness of the two side surfaces 4i was 2.3 μm and 2.2 μm, respectively.

  Then, the fuel cell and the current collecting member are joined as shown in FIG. 7 using a conductive joining material made of LSCF, and heat treatment is performed at 1000 ° C. for 2 hours to join the fuel cell and the current collecting member. Made samples. This sample was heat-treated in the atmosphere at 750 ° C. × 3000 hr, and the cross-section of the sample after the heat treatment was analyzed with EPMA (wavelength dispersive X-ray microanalyzer) to confirm the diffusion state of Cr from the current collecting member. Moreover, the peeling condition of the coating layer in a current collection member was confirmed by SEM (3000 times). As a result, there was no diffusion of Cr into the oxygen electrode layer, and there was no peeling of the coating layer.

1: Cell stack device 2: Cell stack 3: Fuel cell 4: Current collecting member (conductive member)
4a: First current collecting piece (first conductive piece)
4b: Second current collecting piece (second conductive piece)
4g: 1st main surface 4h: 1st side surface 4i: 2nd side surface 4j: 2nd main surface 13: Conductive joining material 20: Fuel cell module 21: Storage container 25: Fuel cell apparatus 41: Current collection board | substrate (conductive board | substrate) )
43: Coating layer

Claims (4)

  An electrolysis cell and a conductive member are alternately arranged, the electrolysis cell and the conductive member are joined with a conductive bonding material, and a plurality of the electrolysis cells are electrically connected, and the conductive stack A member is formed by coating a conductive substrate made of an alloy containing Cr with a coating layer made of ceramics, and a first conductive piece bonded to the first electrolytic cell and a second bonded to the second electrolytic cell. And the thickness of the coating layer on the first main surface of the first conductive piece and the second conductive piece on the side to be joined to the electrolysis cell is opposite to the first main surface. The first main surface of the first conductive piece and the second conductive piece and the side surface formed continuously from the first main surface are thicker than the thickness of the covering layer on the two main surfaces, It is bonded to the electrolytic cell with a bonding material Cell stack.   The electrolysis cell includes an electrode layer and an interconnector layer facing each other, the first conductive piece is joined to the electrode layer, the second conductive piece is joined to the interconnector layer, The corners of one conductive piece and the second conductive piece are chamfered, and the curvature of the corner on the electrode layer side of the first conductive piece is more than the curvature of the corner on the interconnector layer side of the first conductive piece. The cell stack according to claim 1, wherein the cell stack is also small.   An electrolytic module comprising the cell stack according to claim 1 or 2 accommodated in a storage container.   4. An electrolysis apparatus comprising the electrolysis module according to claim 3 and an auxiliary machine for operating the electrolysis module housed in an outer case.

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