JP2017033627A - Solid oxide type fuel battery stack, solid oxide type fuel battery module and solid oxide type fuel battery system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid oxide type fuel battery stack, a solid oxide type fuel battery module and a solid oxide type fuel battery system in which a loss caused by Joule heat can be reduced and adjacent cell bundles can be easily connected to each other.SOLUTION: In a solid oxide type fuel battery stack, a first current collecting member 42 is formed of a metal material, provided to cover plural fuel electrode layer connected portions of solid oxide type fuel battery tubular cells 41 from the outside so that the solid oxide type fuel battery tubular cells 41 are bundled on one end side thereof, and electrically connected to each fuel electrode layer connected portion. A second current collecting member 43 is formed of a metal material, provided to cover plural oxidant gas electrode layer connected portions of the solid oxide type fuel battery tubular cells 41 from the outside thereof so that the plural solid oxide type fuel battery tubular cells 41 are bundled at the other end side thereof, and electrically connected to each oxidant gas electrode layer connected portion.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a solid oxide fuel cell stack, a solid oxide fuel cell module, and a solid oxide fuel cell system in which a plurality of solid oxide fuel cell cylindrical cells are electrically connected.

  Examples of the solid oxide fuel cell stack include the inventions described in Patent Documents 1 to 3. A solid oxide fuel cell described in Patent Document 1 includes a tubular support, a first electrode formed on the outer surface of the support, an electrolyte formed on the outer surface of the first electrode, and an electrolyte. The 2nd electrode formed in the outer surface of this, and the interconnector are provided. The second electrode and the electrolyte are divided into two or more regions in the direction along the longitudinal direction of the support. As a result, the solid oxide fuel cell described in Patent Document 1 has a current path length of current flowing in the direction along the longitudinal direction of the support as compared with the case where the second electrode and the electrolyte are not divided. We are trying to shorten it to reduce electrical resistance and reduce Joule heat losses.

  In the fuel cell described in Patent Document 2, a plurality of cylindrical small cells are arranged in a straight line along the central axis (longitudinal direction of the small cells) of the small cells. The plurality of small cells are electrically connected via a current collecting member. As a result, the fuel cell described in Patent Document 2 tries to suppress loss due to Joule heat and suppress a decrease in output while securing an output equivalent to a long cell integrally formed with a plurality of small cells. Yes.

  In the connection structure of the solid oxide fuel cell described in Patent Document 3, a cell bundle is constituted by three adjacent cylindrical single cells. The three single cells are arranged so as to be inscribed in the first current collecting member having a triangular cross section and arranged so as to be circumscribed on the outside of the second current collecting member. The three single cells are electrically connected in parallel by the first current collecting member and the second current collecting member. Accordingly, the connection structure of the solid oxide fuel cell described in Patent Document 3 attempts to suppress a decrease in output density in a cell bundle in which a plurality of single cells are assembled.

JP 2009-289754 A JP 2013-182700 A Japanese Unexamined Patent Publication No. 7-22060

  However, in the inventions described in Patent Document 1 and Patent Document 2, since the cylindrical fuel cell is divided in the direction along the longitudinal direction, a gas seal at the divided portion is required, and the number of sealed portions increases. . The solid oxide fuel cell is exposed to a high temperature for a longer time than other fuel cells, and a temperature cycle between room temperature and high temperature is added, so that the stress applied to the seal portion increases. For this reason, an increase in the number of seal points causes a decrease in the reliability of the solid oxide fuel cell. Further, when the cylindrical cell is divided in the direction along the longitudinal direction, the shapes of the electrodes and the interconnector may be complicated. Furthermore, when the number of divisions of the fuel cells increases, the number of parts including the connecting members for electrically connecting them increases significantly, which may lead to an increase in production process, complexity, and cost.

  On the other hand, in the invention described in Patent Document 3, since the fuel battery cell is not divided, there is no problem of an increase in the number of seal portions due to the division. However, in the invention described in Patent Document 3, the second current collecting member is provided inside the first current collecting member, and it is not easy to electrically connect adjacent cell bundles. Therefore, in the invention described in Patent Document 3, the second current collecting member is provided so as to protrude in the axial direction with respect to the first current collecting member, and the cell bundle is enlarged in the direction along the longitudinal direction. To do. In addition, the fuel electrode is provided with a notch in the direction along the longitudinal direction, resulting in a complicated shape of the fuel electrode and the interconnector, and an increase and complexity of these manufacturing processes, and an increase in cost. there is a possibility.

  The present invention has been made in view of such circumstances, and can reduce loss due to Joule heat and can easily connect adjacent cell bundles to each other. It is an object of the present invention to provide a physical fuel cell module and a solid oxide fuel cell system.

  A solid oxide fuel cell stack according to the present invention includes: (i) (a) a fuel electrode layer formed in a tubular shape, in which fuel flows from one end side to the other end side, and laminated on the outside of the fuel electrode layer. And an oxidant gas electrode layer provided in the oxidant gas atmosphere, and an electrolyte layer formed between the fuel electrode layer and the oxidant gas electrode layer, and (b) one of the fuel electrode layers The end portion side is exposed and the other end portion side of the fuel electrode layer is covered with the oxidant gas electrode layer, and (c) the fuel electrode layer cover is exposed to the exposed portion on the one end side of the fuel electrode layer. A plurality of solid oxide fuel cell tubular cells in which a connecting portion is formed and an oxidant gas electrode layer connected portion is formed on the other end side of the oxidant gas electrode layer; and (ii) A plurality of solid oxide fuel cell cylindrical cells made of a metal material are bundled on the one end side The first current collecting member provided so as to cover the plurality of fuel electrode layer connected portions of the solid oxide fuel cell cylindrical cell from the outside and electrically connected to each of the fuel electrode layer connected portions And (iii) a plurality of the oxidizers of the solid oxide fuel cell cylindrical cell formed of a metal material and bundled on the other end side of the plurality of solid oxide fuel cell cylindrical cells. A plurality of cell bundles each including a second current collecting member provided to cover the gas electrode layer connected portion from the outside and electrically connected to each of the oxidant gas electrode layer connected portions. The first current collecting member and the second current collecting member are electrically connected.

  According to the solid oxide fuel cell stack according to the present invention, each cell bundle includes a plurality of solid oxide fuel cell cylindrical cells, a first current collecting member, and a second current collecting member. . Therefore, a current path having a smaller electrical resistance than the ohmic resistance of the solid oxide fuel cell cylindrical cell can be formed in the direction along the longitudinal direction of the plurality of solid oxide fuel cell cylindrical cells. Therefore, the solid oxide fuel cell stack according to the present invention can reduce the electric resistance without dividing the solid oxide fuel cell cylindrical cell in the direction along the longitudinal direction, and the loss due to Joule heat. Can be reduced. Further, the first current collecting member and the second current collecting member are juxtaposed in the direction along the longitudinal direction of the plurality of solid oxide fuel cell cylindrical cells, so that adjacent cell bundles are electrically connected to each other. Easy to do.

1 is a configuration diagram illustrating an example of a solid oxide fuel cell system 1. FIG. FIG. 3 is a cross-sectional end view of the solid oxide fuel cell module 11 cut in a direction (arrow Z direction) along the longitudinal direction of a solid oxide fuel cell cylindrical cell 41. FIG. 3 is a perspective view showing a cell bundle group 40, a base member 31, and an anode gas manifold 33 in FIG. 3 is a front view showing an example of a solid oxide fuel cell cylindrical cell 41. FIG. 4 is a front view showing an example of a cell bundle 44. FIG. FIG. 4 is an end view of a cut portion of a cell bundle 44 cut along a plane perpendicular to a direction (arrow Z direction) along a longitudinal direction of a solid oxide fuel cell cylindrical cell 41. It is a VII-VII direction view of FIG. FIG. 5 is a front view showing an example of a state in which adjacent cell bundles 44 and 44 are electrically connected by a cell bundle connection member 45. FIG. 6 is a front view showing an example of a cell bundle 44 in which a plurality (three) of solid oxide fuel cell cylindrical cells 41, 41, 41 are arranged in a straight line according to the second embodiment. FIG. 10 is a cross-sectional end view of the cell bundle 44 of FIG. 9 taken along a plane perpendicular to a direction along the longitudinal direction of the solid oxide fuel cell cylindrical cell 41 (arrow Z direction) according to the second embodiment. .

<First embodiment>
(Solid oxide fuel cell system 1)
As shown in FIG. 1, the solid oxide fuel cell system 1 includes a power generation unit 10 and a hot water storage tank 21. The power generation unit 10 includes a solid oxide fuel cell module 11, a heat exchanger 12, a power conversion device 13, a water tank 14, and a control device 15.

  The solid oxide fuel cell module 11 includes at least a solid oxide fuel cell stack 30 as described later. The solid oxide fuel cell module 11 is supplied with reforming fuel, reforming water, and cathode gas (air). Specifically, the solid oxide fuel cell module 11 has one end connected to the supply source Gs and the other end of the reforming fuel supply pipe 11a to which the reforming fuel is supplied. A raw material pump 11a1 is provided in the reforming fuel supply pipe 11a. Further, the solid oxide fuel cell module 11 has one end connected to the water tank 14 and the other end of the water supply pipe 11b to which reformed water is supplied. The water supply pipe 11b is provided with a reforming water pump 11b1. Further, the solid oxide fuel cell module 11 has one end connected to the cathode air blower 11c1 and the other end of the cathode air supply pipe 11c to which cathode gas (air) is supplied.

  The heat exchanger 12 is a heat exchanger in which combustion exhaust gas exhausted from the solid oxide fuel cell module 11 is supplied and hot water stored in the hot water storage tank 21 is supplied, and heat is exchanged between the combustion exhaust gas and the hot water storage. is there. Specifically, the hot water storage tank 21 stores hot water, and is connected to a hot water circulation line 22 through which the hot water circulates (circulates in the direction of the arrow in FIG. 1). A hot water circulation pump 22a and the heat exchanger 12 are arranged on the hot water circulation line 22 in order from the lower end to the upper end. The heat exchanger 12 is connected (penetrated) with an exhaust pipe 11 d from the solid oxide fuel cell module 11. The heat exchanger 12 is connected to a condensed water supply pipe 12 a connected to the water tank 14.

  In the heat exchanger 12, the combustion exhaust gas from the solid oxide fuel cell module 11 is introduced into the heat exchanger 12 through the exhaust pipe 11d, and is cooled by being exchanged with the stored hot water. Water vapor contained in the combustion exhaust gas is condensed. The cooled combustion exhaust gas is discharged to the outside through the exhaust pipe 11d. Moreover, the condensed condensed water is supplied to the water tank 14 through the condensed water supply pipe 12a. The water tank 14 purifies the condensed water with ion exchange resin.

  The heat exchanger 12, the hot water tank 21, and the hot water circulation line 22 described above constitute an exhaust heat recovery system 20. The exhaust heat recovery system 20 recovers and stores the exhaust heat of the solid oxide fuel cell module 11 in hot water storage.

  The power converter 13 receives the DC voltage output from the solid oxide fuel cell stack 30, converts it to a predetermined AC voltage, and is connected to an AC system power supply 16a and an external power load 16c (for example, an electrical appliance). To the power line 16b. Further, the power conversion device 13 inputs an AC voltage from the system power supply 16a via the power supply line 16b, or inputs a DC voltage of the solid oxide fuel cell stack 30, and converts it to a predetermined DC voltage to compensate. Output to the machine (each pump, blower, etc.) and the control device 15. The controller 15 controls the operation of the solid oxide fuel cell system 1 by driving an auxiliary machine.

(Solid oxide fuel cell module 11)
As shown in FIG. 2, the solid oxide fuel cell module 11 includes a solid oxide fuel cell stack 30, an evaporation unit 50, a reforming unit 60, and a combustion unit 70. The solid oxide fuel cell stack 30 includes a cell bundle group 40.

(Solid oxide fuel cell stack 30)
The solid oxide fuel cell stack 30 includes a base member 31, a cell bundle group 40, a cover 32, an anode gas manifold 33 and a cathode gas manifold 34.

  The base member 31 is a metal plate (for example, ferritic stainless steel, austenitic stainless steel, chrome-iron-yttria alloy, etc., but ferritic stainless steel is particularly suitable) and has a square plate shape. Is formed. As shown in FIGS. 2 and 3, the cell bundle group 40 is erected on the base member 31.

  The cell bundle group 40 includes a plurality (six in this embodiment) of cell bundles 44. Each cell bundle 44 includes a plurality (three in this embodiment) of solid oxide fuel cell cylindrical cells 41, 41, 41, a first current collecting member 42, and a second current collecting member 43. ing. The cell bundle group 40 is configured by electrically connecting a plurality (six) of cell bundles 44 via the first current collecting member 42 and the second current collecting member 43 of each cell bundle 44. Hereinafter, the configuration of each solid oxide fuel cell cylindrical cell 41 will be described in order.

  As shown in FIG. 4, each of the plurality (three) of solid oxide fuel cell cylindrical cells 41, 41, 41 includes a fuel electrode layer 41a, an electrolyte layer 41b, and an oxidant gas electrode layer 41c. These are formed by laminating them in layers. The fuel electrode layer 41a is formed in a cylindrical shape, and the fuel flows from one end side (arrow Z2 direction side) to the other end side (arrow Z1 direction side). In the present embodiment, the fuel is a reformed gas obtained by reforming a hydrocarbon-based raw material such as natural gas described later, and is also referred to as an anode gas.

  The oxidant gas electrode layer 41c is laminated outside the fuel electrode layer 41a and is provided in an oxidant gas atmosphere. In the present embodiment, the oxidant gas is air and is also referred to as a cathode gas. The electrolyte layer 41b is formed between the fuel electrode layer 41a and the oxidant gas electrode layer 41c. That is, each of the plurality (three) of the solid oxide fuel cell cylindrical cells 41, 41, 41 is formed in the order of the fuel electrode layer 41a, the electrolyte layer 41b, and the oxidant gas electrode layer 41c from the inside in the radial direction. ing. As shown in FIG. 4, a reaction preventing layer 41d can be provided between the electrolyte layer 41b and the oxidant gas electrode layer 41c.

  In the present embodiment, each of the plurality (three) of solid oxide fuel cell cylindrical cells 41, 41, 41 is formed in a cylindrical shape. Compared to other fuel cells, the solid oxide fuel cell is exposed to a high temperature and has a temperature cycle in which the temperature difference between the room temperature and the high temperature is large. As a result, each solid oxide fuel cell cylindrical cell 41 repeats thermal expansion and thermal contraction. In the present embodiment, each of the plurality (three) of solid oxide fuel cell cylindrical cells 41, 41, 41 is formed in a cylindrical shape. Therefore, when the above-described temperature cycle is applied to each solid oxide fuel cell cylindrical cell 41, each solid oxide fuel cell cylindrical cell 41 expands or contracts evenly in the circumferential direction. be able to.

  The fuel electrode layer 41a includes, for example, a mixture of a catalytic metal such as Ni or Fe and a stabilized zirconia doped with at least one selected from rare earth elements such as Y, Sc and Ce, and a catalytic metal such as Ni and Fe. A mixture of ceria doped with at least one kind of rare earth elements such as Gd, Y, Sm, lanthanum gallate doped with a catalytic metal such as Ni or Fe and at least one kind selected from Sr, Mg, Co, Fe, Cu And at least one kind of mixture.

  The electrolyte layer 41b includes, for example, stabilized zirconia doped with at least one selected from rare earth elements such as Y, Sc, and Ce, ceria doped with at least one selected from rare earth elements such as Gd, Y, and Sm, Ni, and Sr. , Lanthanum gallate doped with at least one selected from Mg, Co, Fe and Cu.

  The oxidant gas electrode layer 41c includes, for example, lanthanum manganite doped with at least one selected from Sr and Ca, lanthanum ferrite doped with at least one selected from Sr, Co, Ni, and Cu, Sr, Fe Lanthanum cobaltite doped with at least one selected from Ni, Cu, barium cobaltite doped with at least one selected from Sr, Fe, silver, silver-palladium alloy, platinum, etc. Is done.

  The reaction preventing layer 41d can be formed using, for example, a ceria mixture doped with rare earth such as GDC (gadolinium doped ceria), YDC (yttria doped ceria), SDC (samarium doped ceria).

  As shown in FIG. 4, in each of the plurality (three) of solid oxide fuel cell tubular cells 41, 41, 41, one end side (the arrow Z1 direction side) of the fuel electrode layer 41a is exposed. At the same time, the other end side (arrow Z2 direction side) of the fuel electrode layer 41a is covered with the oxidant gas electrode layer 41c. Each of the plurality (three) of solid oxide fuel cell cylindrical cells 41, 41, 41 is formed with a fuel electrode layer connected portion 41a1 and an oxidant gas electrode layer connected portion 41c1. . The fuel electrode layer connected portion 41a1 is formed in an exposed portion on one end side (arrow Z1 direction side) of the fuel electrode layer 41a. The oxidant gas electrode layer connected portion 41c1 is formed on the other end side (arrow Z2 direction side) of the oxidant gas electrode layer 41c.

  In the fuel electrode layer connected portion 41a1, the electrolyte layer 41b and the oxidant gas electrode layer 41c are not formed, but only the fuel electrode layer 41a is formed. A part of the electrolyte layer 41b is exposed. The method for forming the plurality (three) of the solid oxide fuel cell cylindrical cells 41, 41, 41 is not particularly limited. For example, the fuel electrode layer 41a is formed by a known method such as extrusion, pressing, or casting. The electrolyte layer 41b and the oxidant gas electrode layer 41c can be successively formed by a method such as printing, dipping or slurry coating. The same applies to the case where the reaction preventing layer 41 d is formed on the solid oxide fuel cell tubular cell 41.

  By these methods, each of the plurality (three) of the solid oxide fuel cell cylindrical cells 41, 41, 41 has the fuel electrode layer 41a, the electrolyte layer 41b, and the oxidant gas electrode layer 41c from the inside in the radial direction. In order, the above-described electrode materials are laminated in layers. Further, by performing masking according to the part at the stage of film formation, a part where the fuel electrode layer 41a is exposed and a part where the electrolyte layer 41b is exposed are formed. It is also possible to produce a plurality (three) of solid oxide fuel cell tubular cells 41, 41, 41 in which the outer diameter of an arbitrary part is changed by locally forming the film. The same applies to the case where the reaction preventing layer 41 d is formed on the solid oxide fuel cell tubular cell 41.

  The first current collecting member 42 is formed of a metal material, and is electrically connected to each fuel electrode layer connected portion 41a1 of a plurality (three) of solid oxide fuel cell cylindrical cells 41, 41, 41. Is done. The first current collecting member 42 can be formed using, for example, ferritic stainless steel, lanthanum chromite, or the like. The first current collecting member 42 is particularly preferably formed using ferritic stainless steel. Ferritic stainless steel having a high chromium content ratio is excellent in oxidation resistance at high temperatures, and has a smaller thermal expansion coefficient than austenitic stainless steel, and is suitable as the first current collecting member 42.

  As shown in FIGS. 3 and 5, the first current collecting member 42 includes a plurality (three) of solid oxide fuel cell cylindrical cells 41, 41, 41 on one end side (arrow Z <b> 1 direction side). A plurality of (three) fuel electrode layer connected portions 41a1, 41a1, 41a1 of the solid oxide fuel cell cylindrical cells 41, 41, 41 are provided so as to be bundled from outside, It is electrically connected to the layer connected portion 41a1.

  As shown in FIG. 6, the first current collecting member 42 includes main body portions 42 a and 42 b. The main body portion 42a is formed in a thin plate shape and includes flange portions 42a1 and 42a1. Similarly, the main body portion 42b is formed in a thin plate shape and includes flange portions 42b1 and 42b1. In the first current collecting member 42, for example, one flange 42a1 of the main body 42a and one flange 42b1 of the main body 42b are joined by spot welding or the like, and the other flange 42a1 of the main body 42a is joined. The other flange 42b1 of the main body 42b is joined. As shown in FIG. 6, when the main body 42 a and the main body 42 b are joined, the first current collecting member 42 has a direction along the longitudinal direction of the solid oxide fuel cell cylindrical cell 41 (arrow Z The cross-sectional shape cut by a plane perpendicular to (direction) is formed into a substantially equilateral triangle.

  The main body portions 42a, 42b are formed along the outer periphery of a plurality (three) of fuel electrode layer connected portions 41a1, 41a1, 41a1. As described above, the first current collecting member 42 includes a plurality (three) of fuel electrode layer connected portions 41a1, 41a1, 41a1 of the plurality (three) of solid oxide fuel cell tubular cells 41, 41, 41. Are electrically connected to each fuel electrode layer connected portion 41a1. The flange portions 42a1, 42a1, 42b1, and 42b1 can be provided at arbitrary positions except for first flat surface portions 42a3 and 42b3 described later. Moreover, the main-body parts 42a and 42b can also be formed integrally.

  The second current collecting member 43 is made of a metal material, and is electrically connected to each oxidant gas electrode layer connected portion 41c1 of the plurality (three) of solid oxide fuel cell cylindrical cells 41, 41, 41. Connected to. The second current collecting member 43 can be formed of the same metal material as the first current collecting member 42. However, the second current collecting member 43 is preferably formed to be porous. For the second current collecting member 43, for example, a porous metal such as a mesh metal, an expanded metal, or a punching metal can be used. As a result, the second current collecting member 43 can flow the oxidant gas (air), and each of the oxidizers of the plurality (three) of the solid oxide fuel cell cylindrical cells 41, 41, 41. An oxidant gas (air) can be supplied to the gas electrode layer 41c.

  As shown in FIGS. 3 and 5, the second current collecting member 43 includes a plurality (three) of solid oxide fuel cell cylindrical cells 41, 41, 41 on the other end side (arrow Z <b> 2 direction side). A plurality of (three) oxidant gas electrode layer connected portions 41c1, 41c1, 41c1 of the solid oxide fuel cell cylindrical cells 41, 41, 41 so as to be bundled from the outside. The oxidant gas electrode layer connected portion 41c1 is electrically connected.

  As shown in FIG. 6, the second current collecting member 43 includes main body portions 43 a and 43 b. The main body 43a is formed in a thin plate shape like the main body 42a of the first current collecting member 42, and includes flanges 43a1 and 43a1. Moreover, the main-body part 43b is formed in thin plate shape similarly to the main-body part 42b of the 1st current collection member 42, and is provided with the collar parts 43b1 and 43b1. The main body 43 a and the main body 43 b are joined in the same manner as the first current collecting member 42 and have the same cross-sectional shape as the first current collecting member 42. Since the 1st current collection member 42 and the 2nd current collection member 43 are exhibiting the same shape, in Drawing 6, the 1st current collection member 42 and the 2nd current collection member 43 are shown with a code number written together. Has been. In the figure, each solid oxide fuel cell cylindrical cell 41 shows only the outermost peripheral portion (fuel electrode layer connected portion 41a1 or oxidant gas electrode layer connected portion 41c1).

  The main body portions 43a, 43b of the second current collecting member 43 are formed along the outer periphery of a plurality (three) of the oxidant gas electrode layer connected portions 41c1, 41c1, 41c1. As described above, the second current collecting member 43 includes a plurality (three) of the oxidant gas electrode layer connected portions 41c1, 41c1 of the plurality (three) of the solid oxide fuel cell tubular cells 41, 41, 41. , 41c1 are covered from the outside, and are electrically connected to each oxidant gas electrode layer connected portion 41c1. The flange portions 43a1, 43a1, 43b1, and 43b1 can be provided at arbitrary positions except for second flat portions 43a3 and 43b3 described later. Moreover, the main-body parts 43a and 43b can also be formed integrally.

  According to the solid oxide fuel cell stack 30 of the present embodiment, the first current collecting member 42 and the second current collecting member 43 are formed of a metal material. The first current collecting member 42 includes a plurality (three in the present embodiment) of solid oxide fuel cell cylindrical cells 41, 41, 41 so as to be bundled on one end side (arrow Z1 direction side). A plurality (three) of the fuel electrode layer connected portions 41a1, 41a1, 41a1 of the solid oxide fuel cell tubular cells 41, 41, 41 are provided from the outside to be electrically connected to each fuel electrode layer connected portion 41a1. Connected. Further, the second current collecting member 43 includes a plurality of (three) solid oxide fuel cell cylindrical cells 41, 41, 41 so as to be bundled on the other end side (arrow Z2 direction side). A plurality of (three) oxidant gas electrode layer connected portions 41c1, 41c1, 41c1 of the tubular fuel cells 41, 41, 41 are provided from the outside, and each of the oxidant gas electrode layer connected portions 41c1 and Electrically connected.

  Therefore, the solid oxide fuel cell stack 30 of the present embodiment has a plurality (three) of solid oxide fuel cell cylindrical cells 41, 41, 41 in the direction along the longitudinal direction (arrow Z direction), A current path having a smaller electrical resistance than the ohmic resistance of the solid oxide fuel cell cylindrical cell 41 can be formed. Specifically, since the first current collecting member 42 is formed of a metal material, the current path formed by the main body portions 42a and 42b of the first current collecting member 42 is a solid oxide fuel cell cylindrical shape. Compared with the ohmic resistance of the cell 41, the electric resistance is small. The same applies to the second current collecting member 43. Therefore, the solid oxide fuel cell stack 30 of the present embodiment reduces the electric resistance without dividing the solid oxide fuel cell cylindrical cell 41 in the direction along the longitudinal direction (arrow Z direction). And loss due to Joule heat can be reduced. Further, the first current collecting member 42 and the second current collecting member 43 are arranged in a direction (arrow Z direction) along the longitudinal direction of the plurality (three) of solid oxide fuel cell cylindrical cells 41, 41, 41. Since they are arranged side by side, it is easy to electrically connect adjacent cell bundles 44 and 44 to each other.

  Further, according to the solid oxide fuel cell stack 30 of the present embodiment, the second current collecting member 43 of each cell bundle 44 is formed to be porous so that the oxidant gas in the oxidant gas atmosphere can flow. ing. Therefore, the second current collecting member 43 of each cell bundle 44 can circulate an oxidant gas (air), and each of the plurality (three) of solid oxide fuel cell cylindrical cells 41, 41, 41. Oxidant gas (air) can be supplied to the oxidant gas electrode layer 41c. Further, since the second current collecting member 43 is formed to be porous, the stress generated when the plurality (three) of the solid oxide fuel cell cylindrical cells 41, 41, 41 are thermally expanded or contracted. (Torsional stress) can be absorbed, and damage to a plurality (three) of solid oxide fuel cell cylindrical cells 41, 41, 41 can be suppressed.

  The first current collecting member 42 of each cell bundle 44 is formed more densely than the second current collecting member 43. Therefore, the first current collecting member 42 can reduce the electrical resistance per unit area as compared with the second current collecting member 43. Therefore, as shown in FIG. 3, the first current collecting member 42 is in a direction along the longitudinal direction of the solid oxide fuel cell tubular cell 41 (arrow Z direction) as compared with the second current collecting member 43. Although the length is set short, an increase in electrical resistance between the first current collecting member 42 and each fuel electrode layer connected portion 41a1 is suppressed.

  Further, since the oxidant gas electrode layer 41c (oxidant gas electrode layer connected portion 41c1) is laminated outside the fuel electrode layer 41a (fuel electrode layer connected portion 41a1), the first current collecting member 42 When the main body portions 42a and 42b and the main body portions 43a and 43b of the second current collecting member 43 are formed with the same dimensions, the inner wall surfaces 42a2 and 42b2 of the first current collecting member 42 and the fuel electrode layer connected portions 41a1. A gap is formed between The gap may also occur during processing or assembly, and a gap may also be generated between the inner wall surfaces 43a2 and 43b2 of the second current collecting member 43 and each oxidant gas electrode layer connected portion 41c1. There is. If a gap is generated between the inner wall surfaces 42a2 and 42b2 of the first current collecting member 42 and each fuel electrode layer connected portion 41a1, compared to the case where there is no gap, the first current collecting member 42 and each fuel electrode layer covered portion are provided. The electrical resistance between the connecting portion 41a1 increases and the conductivity between the first current collecting member 42 and each fuel electrode layer connected portion 41a1 decreases. The same applies to the second current collecting member 43. When a gap is generated between the inner wall surfaces 43a2 and 43b2 of the second current collecting member 43 and each of the oxidant gas electrode layer connected portions 41c1, the gap is formed. The electrical resistance between the second current collecting member 43 and each oxidant gas electrode layer connected portion 41c1 is increased as compared with the case where there is no second current collecting member 43 and each oxidant gas electrode layer connected portion 41c1. The conductivity between the two decreases.

  Therefore, as shown in FIG. 6, each cell bundle 44 preferably includes the first current collecting member 42 provided with the first conductive member 46 a and the second current collecting member 43 provided with the second conductive member 46 b. It is. The first conductive member 46a is formed of a conductive material. For example, a conductive material such as nickel can be used for the first conductive member 46a, and a lanthanum chromite oxide that is stable in an oxidation-reduction atmosphere can also be used. The first conductive member 46a is preferably formed in a sheet shape. In the present embodiment, the first conductive member 46 a is formed in a sheet shape, and a conductive adhesive is applied and bonded to the inner wall surfaces 42 a 2 and 42 b 2 of the first current collecting member 42. Although a conductive adhesive is not limited, For example, the conductive adhesive containing the component similar to the 1st conductive member 46a can be used. Thereby, the thermal expansion coefficient of a conductive adhesive can be made into the same grade as the thermal expansion coefficient of the 1st electroconductive member 46a. Furthermore, it is preferable that the first conductive member 46a is densely formed and has a gas sealing property. Thereby, the first conductive member 46a can seal the fuel gas.

  The first conductive member 46a has inner wall surfaces 42a2, 42b2 of the first current collecting member 42 so as to fill gaps between the inner wall surfaces 42a2, 42b2 of the first current collecting member 42 and the fuel electrode layer connected portions 41a1. And electrically connect between the first current collecting member 42 and each fuel electrode layer connected portion 41a1. As a result, the electrical resistance between the first current collecting member 42 and each fuel electrode layer connected portion 41a1 is reduced, and the electrical conductivity between the first current collecting member 42 and each fuel electrode layer connected portion 41a1 is reduced. Become good. Further, when the first conductive member 46a is formed in a sheet shape, a current path can be formed on one surface along the inner wall surfaces 42a2 and 42b2 of the first current collecting member 42, and reliability is improved.

  The second conductive member 46b is formed of a conductive material. For the second conductive member 46b, for example, conductive ceramics such as LSC (lanthanum strontium cobaltite) and LSCF (lanthanum strontium iron cobaltite) can be used. The second conductive member 46b is preferably formed in a sheet shape. In the present embodiment, the second conductive member 46 b is formed in a sheet shape, and a conductive adhesive is applied to be bonded to the inner wall surfaces 43 a 2 and 43 b 2 of the second current collecting member 43. Although a conductive adhesive is not limited, For example, the conductive adhesive containing the component similar to the 2nd current collection member 43 can be used. Thereby, the thermal expansion coefficient of a conductive adhesive can be made into the same grade as the thermal expansion coefficient of the 2nd conductive member 46b. Furthermore, it is preferable that the second conductive member 46 b be formed to be porous, like the second current collecting member 43. Thereby, like the 2nd current collection member 43, the 2nd electroconductive member 46b can distribute | circulate oxidizing gas (air).

  The second conductive member 46b is arranged such that the inner wall surface 43a2 of the second current collecting member 43 fills the gap between the inner wall surfaces 43a2, 43b2 of the second current collecting member 43 and each oxidant gas electrode layer connected portion 41c1. , 43b2 to electrically connect the second current collecting member 43 and each oxidant gas electrode layer connected portion 41c1. Thereby, the electrical resistance between the 2nd current collection member 43 and each oxidant gas electrode layer connection part 41c1 is reduced, and between the 2nd current collection member 43 and each oxidant gas electrode layer connection part 41c1. The conductivity of the is improved. Further, when the second conductive member 46b is formed in a sheet shape, a current path can be formed on one surface along the inner wall surfaces 43a2 and 43b2 of the second current collecting member 43, and reliability is improved.

  According to the solid oxide fuel cell stack 30 of the present embodiment, each cell bundle 44 includes the first current collecting member 42 including the first conductive member 46a, and the second current collecting member 43 includes the second conductive member. 46b. Therefore, the electrical resistance between the first current collecting member 42 and each fuel electrode layer connected portion 41a1 is reduced, and the electrical conductivity between the first current collecting member 42 and each fuel electrode layer connected portion 41a1 is good. become. Moreover, the electrical resistance between the 2nd current collection member 43 and each oxidant gas electrode layer connection part 41c1 is reduced, and between the 2nd current collection member 43 and each oxidant gas electrode layer connection part 41c1. Conductivity is improved.

  In addition, as shown in FIG. 6, each cell bundle 44 preferably includes a third conductive member 48a. In the present embodiment, the third conductive member 48a is provided on the first gap forming member 47a. The first gap forming member 47a is provided inside the first current collecting member 42 so that the fuel electrode layer connected portions 41a1 and 41a1 of the adjacent solid oxide fuel cell tubular cells 41 and 41 do not contact each other. A gap is formed between the fuel electrode layer connected portions 41a1 and 41a1. The third conductive member 48a is provided along the outer wall surface 47a1 of the first gap forming member 47a and electrically connects the fuel electrode layer connected portions 41a1.

  The first gap forming member 47a is formed in a columnar shape, and is disposed at the center of a plurality (three) of solid oxide fuel cell tubular cells 41, 41, 41. The outer diameter of the first gap forming member 47a regulates the contact between the fuel electrode layer connected portions 41a1 and 41a1 of the adjacent solid oxide fuel cell tubular cells 41 and 41, and the fuel electrode layer connected portion 41a1. , 41a1 is set such that a gap can be formed between them. The shape of the first gap forming member 47a is not limited to a columnar shape or a cylindrical shape. For example, the first gap forming member 47a can be formed in a polygonal shape such as a triangle or a hexagon in the cross-sectional shape of FIG.

  In the present embodiment, since the third conductive member 48a is provided along the outer wall surface 47a1 of the first gap forming member 47a, the material and the like of the first gap forming member 47a are not limited. That is, the first gap forming member 47a may be formed of a conductive material or an insulating material. Alternatively, the first gap forming member 47a may be formed of a conductive material, and the first gap forming member 47a formed of a conductive material may be used as the third conductive member 48a. The conductive material may contain the same components as the first conductive member 46a. Thereby, the thermal expansion coefficient of the 1st clearance gap formation member 47a can be made comparable as the thermal expansion coefficient of the 1st electroconductive member 46a.

  The third conductive member 48a is formed of a conductive material. The conductive material is not limited, but may contain the same components as the first conductive member 46a. Thereby, fuel gas can be sealed and the thermal expansion coefficient of the 3rd conductive member 48a can be made into the same grade as the thermal expansion coefficient of the 1st conductive member 46a. The third conductive member 48a is preferably formed in a sheet shape. In the present embodiment, the third conductive member 48a is formed in a sheet shape, and a conductive adhesive is applied and bonded to the outer wall surface 47a1 of the first gap forming member 47a. Although a conductive adhesive is not limited, For example, the conductive adhesive containing the component similar to the 1st conductive member 46a can be used. Thereby, the thermal expansion coefficient of a conductive adhesive can be made into the same grade as the thermal expansion coefficient of the 1st electroconductive member 46a.

  According to the solid oxide fuel cell stack 30 of the present embodiment, each cell bundle 44 includes the third conductive member 48a. The third conductive member 48a is provided inside the first current collecting member 42, is formed of a conductive material, and is connected to the fuel electrode layer connected portion of the adjacent solid oxide fuel cell cylindrical cells 41, 41. 41a1 is electrically connected. For this reason, the third conductive member 48a electrically connects the plurality (three) of the fuel electrode layer connected portions 41a1, 41a1, 41a1 of the plurality (three) of the solid oxide fuel cell tubular cells 41, 41, 41. Current paths can be formed, and the conductivity between the fuel electrode layer connected portions 41a1 is improved. Further, when the third conductive member 48a is formed in a sheet shape, a current path can be formed on one surface along the outer wall surface 47a1 of the first gap forming member 47a, and the reliability is improved.

  In the present embodiment, each cell bundle 44 includes a first gap forming member 47a and a third conductive member 48a. Therefore, in the solid oxide fuel cell stack 30 of the present embodiment, it is easy to dispose the third conductive member 48a inside the first current collecting member 42, and a second gap forming member 47b to be described later. Are easily arranged side by side. Alternatively, the third conductive member 48a can be provided in a state where the fuel electrode layer connected portions 41a1 and 41a1 of the adjacent solid oxide fuel cell cylindrical cells 41 and 41 are in contact with each other. In this case, the third conductive member 48a can be provided, for example, along the outer wall surface of the support member having a smaller diameter than the outer diameter of the first gap forming member 47a, and the electric electrode layer connected portions 41a1 are electrically connected. Can be connected. In this case, the second gap forming member 47b, which will be described later, cannot be arranged side by side, but the effects described above for the third conductive member 48a can be obtained.

  As shown in FIG. 6, each cell bundle 44 preferably includes a second gap forming member 47b (corresponding to the gap forming member of the present invention). The second gap forming member 47b is provided inside the second current collecting member 43, and the oxidant gas electrode layer connected portions 41c1 and 41c1 of the adjacent solid oxide fuel cell cylindrical cells 41 and 41 do not contact each other. Thus, a gap is formed between the oxidant gas electrode layer connected portions 41c1 and 41c1.

  The second gap forming member 47b is formed in the same manner as the first gap forming member 47a. Similarly to the first gap forming member 47a, a plurality (three) of solid oxide fuel cell tubular cells 41, 41 are provided. , 41 at the center. The outer diameter of the second gap forming member 47b regulates the contact between the oxidant gas electrode layer connected portions 41c1 and 41c1 of the adjacent solid oxide fuel cell tubular cells 41 and 41, and the oxidant gas electrode layer. It is set so that a gap can be formed between the connected parts 41c1 and 41c1.

  In addition, the modification of a shape, material, etc. of the 2nd clearance gap formation member 47b are the same as that of the 1st clearance gap formation member 47a. However, the conductive material may include the same components as those of the second conductive member 46b. As a result, the oxidant gas (air) can be circulated, and the thermal expansion coefficient of the second gap forming member 47b can be made the same as the thermal expansion coefficient of the second conductive member 46b. Further, the first gap forming member 47a and the second gap forming member 47b can be integrally formed. In this case, the first gap forming member 47a and the second gap forming member 47b are preferably formed of an insulating material. As the insulating material, for example, alumina or the like can be used. Thereby, the assembly of each cell bundle 44 is facilitated. In addition, the number of parts can be reduced.

  According to the solid oxide fuel cell stack 30 of the present embodiment, each cell bundle 44 includes the second gap forming member 47b (corresponding to the gap forming member of the present invention). Therefore, the second gap forming member 47b includes a plurality (three) of oxidant gas electrode layer connected portions 41c1, 41c1, 41c1 of the plurality (three) of solid oxide fuel cell tubular cells 41, 41, 41. Thus, the formation of the closed region can be restricted. Therefore, each oxidant gas electrode layer connected portion 41c1 of the plurality (three) of solid oxide fuel cell cylindrical cells 41, 41, 41 supplies the oxidant gas (air) over substantially the entire circumference. The power generation performance is improved.

  As shown in FIG. 6, each cell bundle 44 preferably includes a fourth conductive member 48b. In the present embodiment, the fourth conductive member 48b is provided on the second gap forming member 47b. The fourth conductive member 48b is provided along the outer wall surface 47b1 of the second gap forming member 47b and electrically connects the oxidant gas electrode layer connected portions 41c1.

  The fourth conductive member 48b is formed of a conductive material. Although a conductive material is not limited, it is good to contain the component similar to the 2nd conductive member 46b. As a result, the oxidant gas (air) can be circulated, and the thermal expansion coefficient of the fourth conductive member 48b can be made the same as the thermal expansion coefficient of the second conductive member 46b. The fourth conductive member 48b is preferably formed in a sheet shape. In the present embodiment, the fourth conductive member 48b is formed in a sheet shape, and a conductive adhesive is applied and bonded to the outer wall surface 47b1 of the second gap forming member 47b. Although a conductive adhesive is not limited, For example, the conductive adhesive containing the component similar to the 2nd conductive member 46b can be used. Thereby, the thermal expansion coefficient of a conductive adhesive can be made into the same grade as the thermal expansion coefficient of the 2nd conductive member 46b.

  According to the solid oxide fuel cell stack 30 of the present embodiment, each cell bundle 44 includes the fourth conductive member 48b. The fourth conductive member 48b is provided on the inner side of the second current collecting member 43, is formed of a conductive material, and the oxidant gas electrode layer cover of the adjacent solid oxide fuel cell cylindrical cells 41, 41. The connection parts 41c1 are electrically connected to each other. Therefore, a plurality (three) of the oxidant gas electrode layer connected portions 41c1, 41c1, 41c1 of the plurality (three) of the solid oxide fuel cell cylindrical cells 41, 41, 41 are provided by the fourth conductive member 48b. Can be formed, and the conductivity between the oxidant gas electrode layer connected portions 41c1 is improved. Further, when the fourth conductive member 48b is formed in a sheet shape, a current path can be formed on one surface along the outer wall surface 47b1 of the second gap forming member 47b, and the reliability is improved. In the present embodiment, each cell bundle 44 includes a second gap forming member 47b and a fourth conductive member 48b. Therefore, in the solid oxide fuel cell stack 30 of the present embodiment, it is easy to dispose the fourth conductive member 48 b inside the second current collecting member 43.

  As shown in FIGS. 3 and 7, a plurality (six) of cell bundles 44 are electrically connected via the first current collecting member 42 and the second current collecting member 43 of each cell bundle 44, and the cell A bundle group 40 is configured. The cell bundle group 40 includes a plurality of (six) first current collecting members 42 of a plurality (six) of cell bundles 44 in a direction along the longitudinal direction of the solid oxide fuel cell tubular cell 41 (arrow Z). As seen from (direction), the outer shape is substantially hexagonal. In FIG. 7, the first gap forming member 47a and the third conductive member 48a are not shown. A method for electrically connecting adjacent cell bundles 44 and 44 is not limited, but the cell bundle group 40 preferably includes a cell bundle connecting member 45. The cell bundle connection member 45 electrically connects adjacent cell bundles 44 and 44.

  As shown in FIG. 6, each cell bundle 44 preferably includes first plane portions 42a3 and 42b3 and second plane portions 43a3 and 43b3. The first flat portions 42a3 and 42b3 are formed in a planar shape on the outer wall surfaces of the main body portions 42a and 42b of the first current collecting member 42. The second flat surfaces 43a3 and 43b3 are formed in a planar shape on the outer wall surfaces of the main body portions 43a and 43b of the second current collecting member 43.

  As shown in FIG. 8, the cell bundle connection member 45 includes a first connection part 45a, a second connection part 45b, a connection part 45c, and a stop part 45d. The cell bundle connecting member 45 can be formed of the same metal material as the first current collecting member 42 and the second current collecting member 43. The first connection portion 45a is formed in a flat plate shape, and the first plane portions 42a3 and 42b3 of one cell bundle 44 (the cell bundle 44 on the left side of the paper in the figure) of the adjacent cell bundles 44 and 44. Alternatively, the second flat surface portions 43a3 and 43b3 (in the present embodiment, the first flat surface portions 42a3 and 42b3) are in surface contact and can be electrically connected. The first surface contact portion 45a1 shown in the drawing is a portion in surface contact with the first flat surface portions 42a3 and 42b3.

  The second connection portion 45b is formed in a flat plate shape, and the first plane portions 42a3 and 42b3 of the other cell bundle 44 (the cell bundle 44 on the right side of the paper surface in the figure) of the adjacent cell bundles 44 and 44. Alternatively, the second flat surface portions 43a3 and 43b3 (in this embodiment, the second flat surface portions 43a3 and 43b3) can be electrically connected in surface contact. 2nd surface contact part 45b1 shown to the figure is a site | part which is in surface contact with 2nd plane part 43a3, 43b3.

  The connecting portion 45c is formed in a flat plate shape, and connects the first connecting portion 45a and the second connecting portion 45b to electrically connect them. One end side of the connecting portion 45c is connected to the lower end side (arrow Z2 direction side) of the first surface contact portion 45a1 of the first connecting portion 45a, and the other end side of the connecting portion 45c is the second connecting portion 45b. It is connected to the upper end side (arrow Z1 direction side) of the second surface contact portion 45b1. Therefore, the connection part 45c can connect between the 1st connection part 45a and the 2nd connection part 45b in the shortest distance.

  The stop portion 45d is formed in a bowl shape and is provided on the upper end side (arrow Z1 direction side) of the first surface contact portion 45a1 of the first connection portion 45a. The stopping portion 45d is provided on the main body portions 42a and 42b of the first current collecting member 42 or the main body portions 43a and 43b of the second current collecting member 43 (in this embodiment, the main body portions 42a and 42b of the first current collecting member 42). It can be hooked. Therefore, it is easy to fix the cell bundle 44 and the cell bundle connection member 45 as compared with the case where the stopper 45d is not provided.

A conductive adhesive is applied between the first surface contact portion 45a1 and the first flat surface portions 42a3, 42b3, and the first connection portion 45a and the first flat surface portions 42a3, 42b3 are fixed and electrically connected. Connection is possible. Further, a conductive adhesive is applied between the second surface contact portion 45b1 and the second flat surface portions 43a3 and 43b3, and the second connection portion 45b and the second flat surface portions 43a3 and 43b3 are fixed. In addition, it can be electrically connected. As the conductive adhesive, for example, a conductive paste such as platinum, silver, copper, or a silver-palladium alloy, or conductive ceramics can be used. As the conductive ceramic, for example, an ABO ₃ type perovskite oxide can be used, and a lanthanum cobaltite oxide having a relatively high electrical conductivity or a lanthanum chromite oxide stable in an oxidation-reduction atmosphere can be used. Can do.

  According to the solid oxide fuel cell stack 30 of this embodiment, the cell bundle connection member 45 is provided, and the cell bundle connection member 45 includes a first connection part 45a, a second connection part 45b, and a connection part 45c. Yes. Each cell bundle 44 includes first plane portions 42a3 and 42b3 and second plane portions 43a3 and 43b3. Therefore, the first connection portion 45a is in surface contact with the first flat surface portions 42a3 and 42b3 or the second flat surface portions 43a3 and 43b3 (in the present embodiment, the first flat surface portions 42a3 and 42b3), so that the first current collecting member 42 is obtained. Alternatively, the second current collecting member 43 (first current collecting member 42 in the present embodiment) and the cell bundle connecting member 45 can be electrically connected. The second connecting portion 45b is in surface contact with the first flat surface portions 42a3 and 42b3 or the second flat surface portions 43a3 and 43b3 (in this embodiment, the second flat surface portions 43a3 and 43b3), and the first current collecting member 42 Alternatively, the second current collecting member 43 (second current collecting member 43 in this embodiment) and the cell bundle connecting member 45 can be electrically connected. Therefore, the solid oxide fuel cell stack 30 according to the present embodiment has the first current collecting member 42 and the cell bundle connecting member 45 that are electrically connected by point contact or line contact. The electrical resistance between the one current collecting member 42 and the cell bundle connecting member 45 can be reduced, and the loss due to Joule heat can be reduced. This is the same between the second current collecting member 43 and the cell bundle connecting member 45. Moreover, the cell bundle connection member 45 can electrically connect the adjacent cell bundles 44 and 44 at the shortest distance, and can simplify the shape of the connection member.

  In each cell bundle 44, a plurality (three) of solid oxide fuel cell cylindrical cells 41, 41, 41 are connected in parallel. Further, in the solid oxide fuel cell stack 30, a plurality of (six) cell bundles 44 are connected in series to form a cell bundle group 40. That is, the plurality (18) of solid oxide fuel cell cylindrical cells 41 constituting the cell bundle group 40 are electrically connected by using both serial connection and parallel connection. Therefore, the solid oxide fuel cell stack 30 of the present embodiment can arbitrarily set the output voltage, the output current, and the like, and the degree of freedom in stack design is improved.

  In addition, the 1st connection part 45a can also be in surface contact with 2nd plane part 43a3, 43b3, and can electrically connect between the 2nd current collection member 43 and the cell bundle connection member 45. FIG. The second connecting portion 45b can also be in surface contact with the first flat surface portions 42a3 and 42b3 to electrically connect the first current collecting member 42 and the cell bundle connecting member 45. Furthermore, all or some of the plurality (six) of cell bundles 44 can be connected in parallel. In this case, one cell bundle connecting member 45 connects the first current collecting members 42 of the adjacent cell bundles 44 and the other one cell bundle connecting member 45 is adjacent to the cell bundle. 44 second current collecting members 43 are connected to each other.

  As shown in FIGS. 2 and 7, both ends of a plurality (six) of cell bundles 44 connected in series are connected to a bus bar 35. The bus bar 35 includes a pair of bus bar connecting members 35a and 35a and a pair of bus bar main body portions 35b and 35b. The bus bar 35 is made of a metal material such as copper or aluminum. The pair of bus bar connecting members 35a and 35a are each formed in a plate shape, and the pair of bus bar main body portions 35b and 35b are each formed in a bar shape.

  The first current collecting member 42 of the cell bundle 44 on one end side of the plurality (six) of cell bundles 44 connected in series is connected to one bus bar connecting member 35a of the pair of bus bar connecting members 35a, 35a. Yes. The bus bar connecting member 35a is connected to one bus bar main body portion 35b of the pair of bus bar main body portions 35b and 35b. The second current collecting member 43 of the cell bundle 44 on the other end side of the plurality (six) of cell bundles 44 connected in series is connected to the other bus bar connecting member 35a of the pair of bus bar connecting members 35a, 35a. It is connected. The bus bar connecting member 35a is connected to the other bus bar main body portion 35b of the pair of bus bar main body portions 35b and 35b. The pair of bus bar main body portions 35b and 35b are provided so as to penetrate the base member 31, and can extract DC power generated by a plurality (18) of solid oxide fuel cell cylindrical cells 41 to the outside. It is possible.

  As shown in FIGS. 2 and 3, a plurality (18) of solid oxide fuel cell cylindrical cells 41 constituting the cell bundle group 40 are provided through the base member 31. The base member 31 is formed with a plurality (18 pieces) of through holes (not shown) having a diameter slightly larger than the outer diameter of the solid oxide fuel cell cylindrical cell 41. The cell 41 is inserted into the corresponding through hole. A seal member 36 seals between the through hole of the base member 31 and each solid oxide fuel cell cylindrical cell 41. As the seal member 36, for example, a glass-based seal material can be used.

  In addition, a heat insulating member can be provided between the lower end of the second current collecting member 43 of each cell bundle 44 and the base member 31. The heat insulating member can be formed of an insulating and heat insulating material (for example, ceramics made from aluminum oxide, magnesium oxide, silicon oxide, or a mixed material thereof). Thereby, the temperature of the seal part of the seal member 36 can be reduced. Therefore, the sealing member 36 can be made of a flexible silicon-based sealing material, which is preferable because it provides good gas sealing properties.

  As shown in FIG. 2, the cover 32 is attached to the upper surface of the base member 31. The cover 32 is formed in a box shape having an opening that opens downward. The sealed space R1 formed between the cover 32 and the base member 31 accommodates the upper part of the cell bundle group 40, the evaporation unit 50, and the reforming unit 60. A flange 32a formed outward is formed in the opening of the cover 32. The flange 32a contacts the upper surface of the base member 31, and is fixed to the base member 31 by screws 32b. Yes. Exhaust ports 32c and 32c are formed in the ceiling portion of the cover 32, and combustion exhaust gas is exhausted through the exhaust ports 32c and 32c.

  The anode gas manifold 33 is attached to the lower surface of the base member 31. The anode gas manifold 33 is formed in a box shape having an opening that opens upward. A sealed space formed between the anode gas manifold 33 and the base member 31 accommodates the lower part of the cell bundle group 40. A support plate (not shown) is provided in the anode gas manifold 33. The cell bundle group 40 is arranged in solid oxide form by arranging the lower end surfaces of a plurality (18) of solid oxide fuel cell tubular cells 41 constituting the cell bundle group 40 in contact with the support plate. The fuel cell cylindrical cell 41 is positioned in the direction along the longitudinal direction (arrow Z direction).

  An insulating plate (not shown) that insulates the two members is provided between the support plate and the plurality (18) of solid oxide fuel cell tubular cells 41. Further, a plurality (18) of through holes (not shown) are formed in the support plate and the insulating plate, respectively, and each formed by the fuel electrode layer 41a of each solid oxide fuel cell cylindrical cell 41. Anode gas can be supplied to each fuel flow path. An anode gas supply pipe 33a is connected to the anode gas manifold 33. One end of the anode gas manifold 33 is connected to the reforming unit 60 to supply anode gas. It is preferable that the through hole through which the anode gas of the support plate passes is provided with an orifice for reducing the flow rate of the anode gas. Thereby, the solid oxide fuel cell stack 30 can make the pressure loss of each solid oxide fuel cell cylindrical cell 41 uniform, and can make the distribution of anode gas uniform. Therefore, the solid oxide fuel cell stack 30 can suppress variations in power generation caused by uneven fuel supply.

  The cathode gas manifold 34 is provided in the space R1. The cathode gas manifold 34 is provided so as to surround a plurality (six) second current collecting members 43 constituting the cell bundle group 40 from the outside. The cathode gas manifold 34 is formed with a plurality of outflow holes (arrow positions in FIG. 2) through which the cathode gas (air) flows out toward the plurality (six) of second current collecting members 43. A cathode gas supply pipe 34 a to which cathode gas (air) is supplied is connected to the cathode gas manifold 34.

(Evaporation part 50)
The evaporation unit 50 is heated by the combustion gas of the solid oxide fuel cell stack 30, evaporates the supplied reforming water to generate water vapor, and preheats the supplied reforming fuel. The evaporation unit 50 mixes the generated water vapor and the preheated reforming fuel and supplies the mixture to the reforming unit 60. Examples of the reforming fuel include gas fuel for reforming such as natural gas and LP gas, and liquid fuel for reforming such as kerosene, gasoline, and methanol. In this embodiment, the reforming fuel uses natural gas. Yes.

  The other end of the water supply pipe 11 b whose one end (lower end) is connected to the water tank 14 is connected to the evaporation unit 50. Further, the other end of the reforming fuel supply pipe 11a having one end connected to the supply source Gs is connected to the evaporation unit 50. The supply source Gs is, for example, a gas supply pipe for city gas or a gas cylinder for LP gas.

(Reformer 60)
The reforming unit 60 is heated from the combustion gas described above and supplied with heat necessary for the steam reforming reaction, so that the reforming unit 60 is fuel from the mixed gas of the steam supplied from the evaporation unit 50 and the reforming fuel. Generate reformed gas. The reforming unit 60 is filled with a catalyst (for example, Ru or Ni-based catalyst), and the mixed gas reacts with the catalyst to be reformed to generate a gas containing hydrogen and carbon monoxide. (So-called steam reforming reaction).

  These generated gases (so-called reformed gases) are the above-described anode gas, and the anode gas manifold 33 of the solid oxide fuel cell stack 30 passes through each solid oxide fuel cell cylindrical cell 41. Derived to each fuel flow path. The reformed gas contains hydrogen, carbon monoxide, carbon dioxide, steam, unreformed natural gas (methane gas), and reformed water (steam) that has not been used for reforming. As described above, the reforming unit 60 generates reformed gas (fuel) from the reforming fuel (raw fuel) and the reformed water and supplies the reformed gas (fuel) to the solid oxide fuel cell stack 30. The steam reforming reaction is an endothermic reaction.

(Combustion part 70)
The combustion unit 70 is provided between the cell bundle group 40 and the evaporation unit 50 and the reforming unit 60. The combustion unit 70 includes a fuel gas (referred to as anode off gas, which is not used for power generation) discharged from a plurality (18) of solid oxide fuel cell cylindrical cells 41 constituting the cell bundle group 40 (also referred to as fuel off gas). Say). The combustion section 70 is supplied with an oxidant gas (referred to as cathode offgas, also referred to as oxidant offgas) that has not been used for power generation. In the combustion unit 70, the anode off-gas and the cathode off-gas are combusted to heat the evaporation unit 50 and the reforming unit 60.

  According to the solid oxide fuel cell module 11 of the present embodiment, the solid oxide fuel cell module 11 including the solid oxide fuel cell stack 30, the evaporation unit 50, and the reforming unit 60 is described above. The effects of the solid oxide fuel cell stack 30 can be obtained. Moreover, according to the solid oxide fuel cell system 1 of the present embodiment, the power generation including the solid oxide fuel cell module 11, the heat exchanger 12, the power conversion device 13, the water tank 14, and the control device 15. In the solid oxide fuel cell system 1 including the unit 10 and the hot water storage tank 21, it is possible to obtain the effects of the solid oxide fuel cell stack 30 described above.

<Second embodiment>
This embodiment differs from the first embodiment in the arrangement of a plurality (three) of solid oxide fuel cell tubular cells 41, 41, 41 of each cell bundle 44. Hereinafter, differences from the first embodiment will be described. In the drawings, the same parts as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  As shown in FIG. 9, a plurality (three) of solid oxide fuel cell cylindrical cells 41, 41, 41 of each cell bundle 44 are arranged in a straight line. Therefore, as shown in FIG. 10, the first current collecting member 42 and the second current collecting member 43 are each formed in a flat shape. Also in the solid oxide fuel cell stack 30 of the present embodiment, the same effects as those described in the first embodiment can be obtained. The same applies to the solid oxide fuel cell module 11 and the solid oxide fuel cell system 1.

  In the present embodiment, a plurality (three) of the solid oxide fuel cell cylindrical cells 41, 41, 41 of each cell bundle 44 are arranged in a straight line. A closed region is not formed by a plurality (three) of the oxidant gas electrode layer connected portions 41c1, 41c1, 41c1 of the solid oxide fuel cell cylindrical cells 41, 41, 41. Therefore, each cell bundle 44 does not include the second gap forming member 47b. Each cell bundle 44 does not include the first gap forming member 47a, the third conductive member 48a, and the fourth conductive member 48b. However, also in the solid oxide fuel cell stack 30 of the present embodiment, each cell bundle 44 can include at least one of the first gap forming member 47a and the second gap forming member 47b. Each cell bundle 44 can include at least one of a third conductive member 48a and a fourth conductive member 48b. In this case, these can be provided between adjacent solid oxide fuel cell tubular cells 41, 41.

<Others>
The present invention is not limited to the embodiments described above and shown in the drawings, and can be implemented with appropriate modifications within the scope not departing from the gist. For example, the number of solid oxide fuel cell cylindrical cells 41 constituting each cell bundle 44 is not limited to three, but may be a plurality. Further, the arrangement of the plurality of solid oxide fuel cell cylindrical cells 41 is not limited to a triangular shape or a straight line shape, but may be an arbitrary shape (for example, a polygonal shape such as a quadrangle or a pentagon). it can. Similarly, the number of cell bundles 44 constituting the cell bundle group 40 is not limited to six, and may be plural. Further, the arrangement of the plurality of cell bundles 44 is not limited to a hexagonal shape, and may be an arbitrary shape (for example, a linear shape, a polygonal shape, etc.).

1: Solid oxide fuel cell system,
10: power generation unit,
11: Solid oxide fuel cell module, 12: Heat exchanger, 13: Power conversion device,
14: Water tank, 15: Control device, 16a: System power supply, 16b: Power supply line,
21: Hot water tank
30: Solid oxide fuel cell stack,
40: Cell bundle group,
41: Solid oxide fuel cell cylindrical cell,
41a: fuel electrode layer, 41a1: fuel electrode layer connected portion,
41b: electrolyte layer,
41c: oxidant gas electrode layer, 41c1: oxidant gas electrode layer connected portion,
42: first current collecting member,
42a2, 42b2: inner wall surface, 42a3, 42b3: first flat surface portion,
43: Second current collecting member,
43a2, 43b2: inner wall surface, 43a3, 43b3: second plane portion,
44: Cell bundle,
45: Cell bundle connection member,
45a: first connection part, 45b: second connection part, 45c: coupling part,
46a: first conductive member, 46b: second conductive member,
47a: first gap forming member,
47b: second gap forming member (corresponding to the gap forming member of the present invention),
48a: third conductive member, 48b: fourth conductive member,
50: evaporation part,
60: reforming section,
70: Combustion part.

Claims (9)

(I) (a) A fuel electrode layer that is formed in a cylindrical shape and in which fuel flows from one end side to the other end side, and an oxidant gas electrode that is stacked outside the fuel electrode layer and provided in an oxidant gas atmosphere And an electrolyte layer formed between the fuel electrode layer and the oxidant gas electrode layer, and (b) one end side of the fuel electrode layer is exposed and the other electrode layer of the fuel electrode layer is exposed. The end side is covered with the oxidant gas electrode layer, and (c) a fuel electrode layer connected portion is formed in the exposed part on the one end side of the fuel electrode layer, and the oxidant gas electrode layer A plurality of solid oxide fuel cell cylindrical cells in which an oxidant gas electrode layer connected portion is formed on the other end side of
(Ii) A plurality of the fuel electrode layer covers of the solid oxide fuel cell cylindrical cell formed of a metal material so as to bundle the plurality of solid oxide fuel cell cylindrical cells on the one end side. A first current collecting member provided to cover the connecting portion from the outside and electrically connected to each of the fuel electrode layer connected portions;
(Iii) A plurality of the oxidant gas electrodes of the solid oxide fuel cell cylindrical cell formed of a metal material so as to bundle the plurality of solid oxide fuel cell cylindrical cells on the other end side A second current collecting member provided to cover the layer connected portion from the outside and electrically connected to each of the oxidant gas electrode layer connected portions;
A solid oxide fuel cell stack in which a plurality of cell bundles are electrically connected via the first current collecting member and the second current collecting member of each cell bundle. Each cell bundle is
Formed of a conductive material and provided along the inner wall surface of the first current collecting member so as to fill a gap between the inner wall surface of the first current collecting member and each connected portion of the fuel electrode layer. A first conductive member that electrically connects the first current collecting member and each fuel electrode layer connected portion;
It is formed of a conductive material and is provided along the inner wall surface of the second current collecting member so as to fill a gap between the inner wall surface of the second current collecting member and each of the oxidant gas electrode layer connected portions. A second conductive member that electrically connects between the second current collecting member and each of the oxidant gas electrode layer connected portions;
A solid oxide fuel cell stack according to claim 1.   3. The solid oxide fuel cell stack according to claim 1, wherein the second current collecting member of each of the cell bundles is formed to be porous so that the oxidant gas in the oxidant gas atmosphere can flow. . A cell bundle connecting member for electrically connecting the adjacent cell bundles;
Each of the cell bundles includes a planar first planar portion formed on the outer wall surface of the first current collecting member and a planar second planar portion formed on the outer wall surface of the second current collecting member. Prepared,
The cell bundle connection member is a first connection portion that can be electrically connected in surface contact with the first plane portion or the second plane portion of one of the adjacent cell bundles, and
A second connection part that can be electrically connected in surface contact with the first plane part or the second plane part of the other cell bundle of the adjacent cell bundles;
A connecting portion for connecting and electrically connecting the first connecting portion and the second connecting portion;
The solid oxide fuel cell stack according to any one of claims 1 to 3.   Each of the cell bundles is provided inside the first current collecting member, is formed of a conductive material, and electrically connects the fuel electrode layer connected portions of the adjacent solid oxide fuel cell cylindrical cells. The solid oxide fuel cell stack according to any one of claims 1 to 4, further comprising a third conductive member to be connected.   Each of the cell bundles is provided inside the second current collecting member, and the oxidant gas is connected so that the oxidant gas electrode layer connected portions of the adjacent solid oxide fuel cell cylindrical cells do not contact each other. The solid oxide fuel cell stack according to any one of claims 1 to 5, further comprising a gap forming member that forms a gap between the pole layer connected portions.   Each of the cell bundles is provided inside the second current collecting member, is formed of a conductive material, and electrically connects the oxidant gas electrode layer connected portions of the adjacent solid oxide fuel cell cylindrical cells. The solid oxide fuel cell stack according to any one of claims 1 to 6, further comprising a fourth conductive member that is electrically connected. A solid oxide fuel cell stack according to any one of claims 1 to 7,
An evaporation section that is heated by the combustion gas of the solid oxide fuel cell stack, evaporates the supplied reforming water to generate steam, and preheats the supplied reforming raw material;
A reforming section for generating a reformed gas as the fuel from the steam supplied from the evaporation section and a mixed gas of the reforming raw material;
A solid oxide fuel cell module. A power generation unit;
A hot water storage tank for storing hot water,
A solid oxide fuel cell system comprising:
The power generation unit is
A solid oxide fuel cell module according to claim 8,
Heat exchange is performed between the combustion exhaust gas exhausted from the solid oxide fuel cell module and the hot water supplied from the hot water storage tank, and water vapor contained in the combustion exhaust gas is condensed to discharge condensed water. A heat exchanger to
A water tank for purifying the condensed water discharged from the heat exchanger;
A control device for driving an auxiliary machine to control the operation of the solid oxide fuel cell system;
A power converter that converts at least DC power output from the solid oxide fuel cell module to AC power and outputs the AC power to a power line connected to an AC power supply; and
A solid oxide fuel cell system.

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