JP5257826B2 - Fuel cell stack, fuel cell stack unit and fuel cell - Google Patents

Description

  The present invention relates to a fuel cell stack of a solid oxide fuel cell (SOFC), and more particularly, an insulating and porous substrate, a tube covering the periphery of the substrate, and electrically connected to each other in series. The present invention relates to a fuel cell stack having a tubular portion laminated on a base so as to include a plurality of fuel cells that are formed.

  The present invention also relates to a fuel cell stack unit having a plurality of the above fuel cell stacks and a manifold to which they are attached. The present invention also relates to a fuel cell having a plurality of the above fuel cell stacks and a case containing them.

  Conventionally, it has an insulating and porous substrate, and a tubular portion laminated on the substrate so as to include a plurality of fuel cells that cover the periphery of the substrate in a tubular shape and are electrically connected to each other in series. A fuel cell stack is known (for example, see Patent Document 1). The fuel cell stack is a structure in which a plurality of fuel cells are combined. Each fuel cell has a fuel electrode and an air electrode, and generates electric power by causing a fuel gas containing hydrogen to act on the fuel electrode and causing air containing oxygen to act on the air electrode. In the case of a fuel cell having the tubular portion, generally, a fuel electrode is disposed inside the tubular portion and an air electrode is disposed outside the fuel electrode.

  An example of a fuel cell stack in which a plurality of fuel cells are combined will be described with reference to the fuel cell stack described in Patent Document 1. FIG. 15 is a perspective view of the fuel cell stack described in Patent Document 1. FIG.

  A fuel cell stack 100 described in Patent Document 1 includes an insulating porous substrate 102 and a plurality of fuel cells 104 that cover the periphery of the substrate 102 in a tubular shape and are electrically connected to each other in series. A tubular portion 106 laminated on the substrate 102 for inclusion. The cross-sectional shape of the fuel cell stack 1 is flat and has planar portions 108 that face each other. The plurality of fuel cells 104 are formed in the flat portion 108 and are arranged in a line from one end 101a of the tubular portion 106 to the other end 101b. In addition, the area of each fuel cell 104 gradually increases from one end 101a to the other end 101b.

  The fuel cell 100 is operated by flowing the fuel gas through the base 102 inside the tubular portion 106 from one end 101 a toward the other end 101 b and flowing air outside the tubular portion 106. When the fuel gas flows from one end 101a toward the other end 101b, hydrogen in the fuel gas is used from the fuel cell 104 on the one end side, so that the fuel gas flows to the other end. It fades as it goes. If fuel cells having the same area are arranged, the generated voltage decreases toward the other end. Furthermore, since the fuel cells having different generated voltages are arranged in series, a current flows forcibly through the fuel cells having a small generated voltage, and the fuel cells deteriorate. However, in the fuel cell stack 100 disclosed in Patent Document 1, since the area of the fuel cell 104 increases toward the other end, the generated voltage of each fuel cell 104 is kept constant. Can do. Moreover, deterioration of the fuel cell 104 can be prevented.

International Publication No. 2004/082058 Pamphlet (see FIGS. 2A to 2C)

  In the fuel cell stack 100 described above, hydrogen in the fuel gas is completely consumed, and so-called fuel depletion may occur, in which no hydrogen is supplied to the fuel cell 104 at the other end. In this case, the fuel cell at the other end becomes defective, and as a result, the entire fuel cell stack in which the fuel cells are electrically connected in series does not function. Therefore, there is room for improving the reliability so that the fuel cell does not become defective and the function of the entire fuel cell stack is maintained even if the fuel runs out.

  In addition, since the area of each fuel cell 104 is determined according to the flow rate and concentration of the fuel gas, it is difficult to design the specifications of the fuel cell.

  Accordingly, the present invention provides a tubular portion laminated on a base so as to include an insulating porous base and a plurality of fuel cells that cover the base in a tubular shape and are electrically connected to each other in series. It is a first object of the present invention to improve the reliability of a fuel cell stack having the above, and to provide a fuel cell stack unit and a fuel cell including the fuel cell stack.

  The present invention further includes a tubular portion laminated on the base so as to include an insulating and porous base and a plurality of fuel cells that cover the periphery of the base and are electrically connected to each other in series. And to provide a fuel cell stack unit and a fuel cell including the fuel cell stack, and to provide a fuel cell stack unit including the fuel cell stack. The purpose is.

In order to achieve the above object, the present invention provides a fuel cell stack unit in which a plurality of fuel cell stacks in which a plurality of fuel cells are stacked on a substrate are electrically connected, wherein the substrate has a longitudinal direction. The cross section orthogonal to the longitudinal direction has a shape with a small thickness with respect to the width, and has a hole penetrating from one end to the other end along the longitudinal direction. In the fuel cell stack unit having an electrolyte and an air electrode, one of air and fuel gas flows from one end of the hole of the base to the other end, and the other of air and fuel gas is outside the fuel cell stack. Each of the fuel cell stacks has a fuel electrode terminal and an air electrode terminal electrically connected to the fuel electrode and the air electrode of the fuel cell, respectively. The first peripheral surface portion and the second peripheral surface portion that are located on the opposite sides of the substrate, and the first connection surface portion that is located on the opposite sides in the width direction of the base and connects the first peripheral surface portion and the second peripheral surface portion. And each of the fuel cell stacks is electrically connected to each fuel electrode terminal and air electrode terminal of the fuel cell stack, and the first peripheral surface portion of the base body. Alternatively, the plurality of electrode connection portions are electrically connected in series via a plurality of electrode connection portions provided apart from each other along the second peripheral surface portion, and the plurality of electrode connection portions are fuel cells of the fuel cell. It is provided near the center of the stack .

In the present invention, preferably, the plurality of electrode connection portions are provided with the central portion of the first peripheral surface portion or the second peripheral surface portion of the base interposed therebetween.

  In the present invention, preferably, each of the fuel cell stacks has a current along the first connection surface portion from the fuel electrode terminal on the first peripheral surface portion side to the air electrode terminal on the second peripheral surface portion side. And a current is caused to flow along the second connection surface portion from the fuel electrode terminal on the second peripheral surface portion side toward the air electrode terminal on the first peripheral surface portion side.

  According to the present invention, a fuel cell stack unit with improved reliability can be provided.

It is a schematic perspective view of the reference example of the fuel cell stack by this invention . FIG. 2 is a schematic cross-sectional view taken along line II-II in FIG. 1. It is sectional drawing similar to FIG. 2 of 1st Embodiment of the fuel cell stack by this invention . It is a sectional view similar to FIG. 2 of a second embodiment of a fuel cell stack according to the present invention. It is a perspective view of the reference example of the fuel cell stack unit by this invention . It is a perspective view of the fuel battery cell stack which attached the electrode connection member. It is a perspective view of an electrode connection member. It is the schematic which shows the flow of electricity of a fuel cell stack unit. It is a perspective view which shows embodiment of an electrode connection member. It is a perspective view which shows the modification of an electrode connection member. It is the schematic which shows the flow of electricity of embodiment of a fuel cell stack unit. 1 is a perspective view of an embodiment of a fuel cell stack unit according to the present invention . 1 is a schematic front view of a first embodiment of a fuel cell according to the present invention . FIG. 3 is a schematic plan view of a second embodiment of a fuel cell according to the present invention . It is a perspective view of a conventional fuel cell stack.

Hereinafter, reference examples and embodiments of a fuel cell stack according to the present invention will be described with reference to the drawings. Here, the fuel cell stack refers to one structure including a plurality of fuel cells.

FIG. 1 is a schematic perspective view of a reference example of a fuel cell stack according to the present invention. FIG. 2 is a schematic cross-sectional view taken along line II-II in FIG.

As shown in FIG. 1, a fuel cell stack 1 which is a reference example of the present invention includes an insulating and porous base 2, a base 2 covering the periphery of the base 2, and including a plurality of fuel cells 4. And a tubular portion 6 laminated on the substrate 2. In this fuel cell stack 1, one of air and fuel gas is caused to flow from one end 1 a to the other end 1 b through the base 2 located inside the tubular portion 6, and the other of air and fuel gas Is caused to flow outside the tubular portion 6.
Hereinafter, as an example, a fuel cell stack 1 having a structure in which fuel gas flows in a base body 2 located inside a tubular portion 6 will be described. The direction in which the fuel gas flows is referred to as a pipe gas flow direction F. The base body 2 has an elongated cross section perpendicular to the in-tube gas flow direction F, and has a plurality of holes 8 penetrating in the in-tube gas flow direction F. The substrate 2 is preferably formed of at least one of zirconia, magnesia, spinel, forsterite and the like doped with at least one selected from rare earth elements such as Ca and Y.

As shown in FIG. 2, the peripheral surface of the base body 2 on which the tubular portions 6 are laminated includes two plane portions 10 a and 10 c positioned on the opposite sides, and two plane portions 10 a and 10 c connected to each other and positioned on the opposite sides. It has connecting surface portions 10b and 10d. In this reference example , two fuel cells 4a and 4b are formed on one flat portion 10a, and two fuel cells 4c and 4d are formed on the other flat portion 10b. Each fuel cell 4a-4d has the same structure. Hereinafter, the component a of the fuel battery cell 4a will be described with reference symbol a, and the corresponding component of the other fuel cell 4b-4d will be labeled with reference symbols b to d, and the description thereof will be given. Omitted. In FIG. 2, in order to explain the constituent elements of the fuel cells 4 a to 4 d, their thickness is shown larger than the thickness of the base 2.

  The fuel cell 4a includes a fuel electrode 12a stacked on the base 2, an electrolyte 14a stacked so as to cover the fuel electrode 12a, an air electrode 16a stacked on the electrolyte 14a, and an air electrode 16a. And a current collecting layer 18a laminated thereon. The electrolyte 14 a is formed of a dense material that does not allow air or fuel gas to pass therethrough, and has a tubular structure that covers the fuel electrode 12 a and the substrate 2. The electrolytes 14a to 14b are not separated but constitute an integral layer 14.

  The fuel electrode 12a includes, for example, a mixture of Ni and a zirconia doped with at least one selected from rare earth elements such as Ca, Y, and Sc, and a mixture of Ni and ceria doped with at least one selected from rare earth elements. And a mixture of Ni and lanthanum gallate doped with at least one selected from Sr, Mg, Co, Fe, and Cu.

  The electrolyte 14a is, for example, zirconia doped with at least one selected from rare earth elements such as Y and Sc, ceria doped with at least one selected from rare earth elements, and lanthanum gallate doped with at least one selected from Sr and Mg. It is formed from at least one kind.

  The air electrode 16a is selected from, 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, Ni and Cu. It is formed from at least one of samarium cobalt, silver, etc. doped with at least one.

  The current collecting layer 18a is preferably a porous conductive film containing silver from the viewpoint of conductivity and air permeability.

  The thickness T of the substrate 2 is, for example, 2 mm, the thickness of the fuel electrode 12a is, for example, 50 μm, the thickness of the electrolyte 14a is, for example, 30 μm, and the thickness of the air electrode 16a is, for example, 30 μm, and the thickness of the current collecting layer 18 a is, for example, 10 μm. The width W of the base 2 is, for example, 30 mm, and the length L of the base 2 is, for example, 80 mm (see FIG. 1).

  The fuel cell stack 1 further includes interconnectors 20a to 20d and an extended current collecting layer 22 for connecting the fuel cells 4a to 4d in series.

  The interconnectors 20 a to 20 d protrude from the fuel electrode 12 of each fuel cell 4 a to 4 d through the electrolyte 14 and are separated from the air electrode 16 and the current collecting layer 18. The interconnectors 20a to 20d are formed of, for example, at least one of lanthanum chromite doped with at least one selected from Sr, Ca and Mg, silver brazing, an alloy containing silver and silver, a mixture of silver and glass, and the like. . The thickness of the interconnectors 20a to 20d is, for example, 60 μm.

  The extended current collecting layer 22 is laminated on the electrolyte 14 of one connection surface portion 10b. The extended current collecting layer 22 is preferably a conductive member containing silver from the viewpoint of electrical connection, and may be the same material as the current collecting layer 18 or the same as the interconnectors 20a to 20d. It may be a material. The extension current collecting layer 22 has a thickness of 20 μm, for example.

  As shown in FIG. 1, each of the fuel cells 4a to 4d, the interconnectors 20a to 20d, and the extended current collecting layer 22 have a form extending from one end 1a to the other end 1b. In FIG. 1, the current collecting layers 18a and 18b, the interconnector 20a, and the extended current collecting layer 22 of the fuel cells 4a and 4b are visible. The fuel electrodes 12a to 12d, the air electrodes 16a to 16d, and the current collecting layers 18a to 18d are stacked in a rectangular shape.

The four fuel cells 4a to 4d are arranged in a line in the circumferential direction of the tubular portion 6 and are electrically connected to each other in series. Specifically, as shown in FIG. 2, the air electrode 16a and the current collecting layer 18a of the first fuel cell 4a and the fuel electrode 12b of the second fuel cell 4b are connected via an interconnector 20b. The current collecting layer 18 of the second fuel battery cell 4b and the fuel electrode 12c of the third fuel battery cell 4c are connected via the extended current collecting layer 22 and the interconnector 20c, and the third fuel battery cell 4c The air electrode 16c and the current collecting layer 18c are connected to the fuel electrode 12d of the fourth fuel cell 4d via the interconnector 20d. Thereby, a series connection cell group extending from the fourth fuel cell 4d to the first fuel cell 4a via the third and second fuel cells 4c, 4b, that is, a series of series connected to each other in series. A group 24a of fuel cells 4 is configured. In this reference example , the fuel cell stack 1 has a single series-connected cell group 24a. In the series-connected cell group 24a, the interconnector 20a functions as the fuel electrode terminal 26, the current collecting layer 18d of the fourth fuel cell 4d functions as the air electrode terminal 27, and the fuel electrode terminal 26 and the air electrode terminal. 27 is taken out. All of the above connections are made from one end 1a to the other end 1b.

  The air electrode 16a of the first fuel cell 4a and the air electrode 16c of the third fuel cell 4c may not be connected to the interconnectors 20b and 20d, respectively. However, as shown in FIG. 2, the air electrodes 16a and 16c are preferably arranged so as to be connected to the interconnectors 20b and 20d together with the current collecting layers 18a and 18c. Thereby, the reliability of the electrical connection between the air electrodes 16a and 16c and the interconnectors 20b and 20d can be ensured, and the air electrodes 16a and 16c exposed through the current collecting layers 18a and 18c can be secured. The power generation output can be increased by increasing the area.

Next, an example of how to make a fuel cell stack according to a reference example of the present invention will be described.

  First, a porous substrate 2 is formed by extruding an insulating substrate raw material powder. From the viewpoint of adjusting the degree of porosity, a pore former such as spherical particles of cellulose or fibrous graphite may be added to the raw material powder.

  Next, the fuel electrodes 12 a to 12 d are screen-printed on the substrate 2. Screen printing is performed so that the base 2 is rotated in the circumferential direction, and is performed on both planar portions 10a and 10c. Instead of screen printing the fuel electrodes 12a to 12d, for example, the fuel electrodes 12a to 12d previously formed into a sheet shape may be attached to the base 2 by the doctor blade method.

  Next, portions where the interconnectors 20a to 20d are formed are masked, the electrolyte 14 is slurry-coated, and the substrate 2, the fuel electrodes 12a to 12d, and the electrolyte 14 are co-fired at 1400 ° C., for example.

  Next, the air electrodes 16a to 16d are screen-printed in the same manner as the fuel electrodes 12a to 12d, and fired at 1100 ° C., for example. Instead of screen printing the air electrodes 16a to 16d, for example, the air electrodes 16a to 16d previously formed into a sheet shape may be attached to the electrolyte 14 by a doctor blade method.

  Next, the interconnectors 20a to 20d are formed by screen printing. Instead of screen printing the interconnectors 20a to 20d, for example, the interconnector powder may be pasted and applied directly. The interconnectors 20a to 20d are preferably formed so as to be directly connected to the air electrodes 16a to 16d.

  Finally, the current collecting layers 18a to 18d and the extended current collecting layer 22 are formed by screen printing, and the interconnectors 20a to 20d, the current collecting layers 18a to 18d and the extended current collecting layer 22 are co-fired at 800 ° C., for example. . Instead of screen printing the current collecting layers 18a to 18d and the extended current collecting layer 22, for example, the current collecting layers 18a to 18d previously formed into a sheet shape are doctor blades on the air electrodes 16a to 16d and the interconnectors 20b to 20d. You may paste by the method.

Next, the operation of the fuel cell according to the reference example of the present invention will be described.

  Fuel gas is supplied to the hole 8 of the base body 2 from one end 1a. Since the substrate 2 is porous, the fuel gas spreads not only to the holes 8 but to the entire substrate 2. The fuel gas includes hydrogen, a reformed gas obtained by reforming hydrocarbon fuel, and the like, and acts on the fuel electrode 12. The fuel gas becomes thinner toward the other end 1b due to the power generation reaction.

  Air is supplied around the tubular portion 6 of the fuel cell stack 1 and toward the other end 1b. The air contains oxygen and passes through the porous current collecting layer 18 to interact with the air electrode 16. Although air becomes thinner toward the other end 1b due to a power generation reaction, air is usually supplied in a relatively large amount for the purpose of controlling the operating temperature of the fuel cell.

  By electrically connecting the fuel electrode terminal 26, that is, the interconnector 20a, and the air electrode terminal 27, that is, the current collecting layer 18d of the fourth fuel cell 4d, the power generation effect of the fuel cell stack 1 is obtained. can get.

  The fuel gas that has not acted on the fuel electrodes 12a to 12d is combusted together with oxygen in the air when it exits from the other end 1b.

In the fuel cell stack 1 according to the reference example of the present invention, each fuel cell 4 functions at the one end 1a even when the fuel ends up at the other end 1b. The cell 4 itself does not become defective. As a result, the power generation effect of the fuel cell stack 1 is maintained, and the fuel cell stack 1 with high reliability can be provided.

  In addition, when fuel withering occurs at the other end 1b, the power generation efficiency of each fuel cell 4 decreases, but the fuel cells 4 are arranged in a row in the circumferential direction perpendicular to the in-pipe gas flow direction F. Therefore, the reduction in power generation efficiency of each of the fuel cells 4a to 4d electrically connected in series is almost the same. Accordingly, the voltage generated by each of the fuel cells 4a to 4d is substantially constant, and the deterioration of each of the fuel cells 4a to 4d is prevented, that is, the durability is improved.

Also, the fuel cell stack 1 according to the reference example of the present invention differs from the conventional fuel cell stack in that the area of the fuel electrodes 12a to 12d, the air electrodes 16a to 16d, and the current collecting layers 18a to 18d is set to each fuel cell. Since it can be made the same in 4a-4d, a design and manufacture become easy. For example, in order to increase the generated voltage of the fuel cell stack 1, the number of cells may be increased. To increase the current, the areas of the fuel electrodes 12a to 12d and the air electrodes 16a to 16d can be increased. That's fine. Therefore, according to the fuel cell stack 1 according to the reference example of the present invention, it is easy to generate a relatively high voltage even if it is small.

Next, a first embodiment of a fuel cell stack according to the present invention. FIG. 3 is a cross-sectional view similar to FIG. 2 of the first embodiment of the fuel cell stack according to the present invention.

As shown in FIG. 3, the fuel cell stack 30 according to the first embodiment of the present invention is the same as the fuel cell stack 1 as the reference example except that the connection method of the fuel cells 4 a to 4 d is different. It has the structure of. Schematically, the second and third fuel cells 4b and 4c are electrically connected in series, and the fourth and first fuel cells 4d and 4a are electrically connected in series.

  Specifically, the extended current collecting layer in which the current collecting layer 18b of the second fuel battery cell 4b and the fuel electrode 12c of the third fuel battery cell 4c are stacked on the electrolyte 14 of one connecting surface portion 10b. 22 and the interconnector 20c. Thereby, the first series connection cell group 24b extending from the third fuel cell 4c to the second fuel cell 4b is configured. In the first series-connected cell group 24b, the interconnector 20b functions as the fuel electrode terminal 26a, and the current collecting layer 18c of the third fuel cell 4c functions as the air electrode terminal 27a. The voltage between the air electrode terminal 27a is taken out.

  Also, an extended current collecting layer 23 in which the current collecting layer 18d of the fourth fuel cell 4d and the fuel electrode 12a of the first fuel cell 4a are laminated on the electrolyte 14 of the other connecting surface portion 10d, and It is connected via the interconnector 20a. Thereby, the 2nd series connection cell group 24c extended from the 1st fuel cell 4a to the 4th fuel cell 4d is comprised. The second series connection cell group 24c is insulated from the first series connection cell group 24b. In the second series-connected cell group 24c, the interconnector 20d functions as the fuel electrode terminal 26b, and the current collecting layer 18a of the first fuel cell 4a functions as the air electrode terminal 27b. The voltage between the air electrode terminal 27b is taken out.

  Thus, in the present embodiment, the fuel cell stack 30 has two series-connected cell groups 24b and 24c. The fuel electrode terminal 26a of the first series connection cell group 24b and the air electrode terminal 27b of the second series connection cell group 24c are arranged on one plane portion 10a, and the air electrode terminal of the first series connection cell group 24b. It is preferable that the fuel electrode terminal 26b of 27b and the 2nd series connection cell group 24c is arrange | positioned at the other plane part 10c.

Next, a second embodiment of the fuel cell stack will be described. FIG. 4 is a cross-sectional view similar to FIG. 2 of the second embodiment of the fuel cell stack according to the present invention.

As shown in FIG. 4, the fuel cell stack 40 according to the second embodiment of the present invention is the same as the fuel cell stack 1 as the reference example except that the connection method of the fuel cells 4a to 4d is different. It has the structure of. Schematically, the second to fourth and first fuel cells 4b, 4c, 4d, 4a are electrically connected in series.

  Specifically, as shown in FIG. 4, the current collecting layer 18d of the second fuel cell 4b and the fuel electrode 12c of the third fuel cell 4c are connected via the extended current collecting layer 22 and the interconnector 20c. Then, the air electrode 16c and the current collecting layer 18c of the third fuel cell 4c and the fuel electrode 12d of the fourth fuel cell 4d are connected via the interconnector 20d, and the fourth fuel cell 4d is collected. The electric layer 18d and the fuel electrode 12a of the first fuel cell 4a are connected via the extended current collecting layer 23 and the interconnector 20a. Thereby, a series connection cell group 24d extending from the first fuel cell 4a to the second fuel cell 4b via the fourth and third fuel cells 4d and 4c is formed. In the present embodiment, the fuel cell stack 40 has a single series-connected cell group 24d. In the series-connected cell group 24d, the interconnector 20b functions as the fuel electrode terminal 26, the current collecting layer 18a of the first fuel cell 4a functions as the air electrode terminal 27, and the fuel electrode terminal 26 and the air electrode terminal. 27 is taken out.

Next, a reference example of the fuel cell stack unit will be described. FIG. 5 is a perspective view of a reference example of the fuel cell stack unit according to the present invention.

A fuel cell stack unit 50 as a reference example of the present invention has a fuel gas manifold 52 and 25 fuel cell stacks 1 according to a reference example disposed thereon.

  The fuel gas manifold 52 is a horizontally long rectangular parallelepiped sealed box, and has a fuel gas space 54 filled with fuel gas therein. The fuel gas space 54 communicates with the hole 8 of each fuel cell stack 1. Fuel gas is supplied to the fuel gas space 54 from a fuel gas supply pipe (not shown). The fuel gas supply pipe (not shown) is preferably connected to a reformed gas apparatus (not shown).

  The fuel cell stack 1 is airtightly fixed using brazing or glass on the fuel gas manifold 52 in a row so that the planar portions 10a and 10b of the adjacent fuel cells 1 face each other. Adjacent fuel cells 1 are electrically connected in series via electrode connection members 56.

  FIG. 6 is a perspective view of a fuel cell stack having an electrode connecting member attached thereto. FIG. 7 is a perspective view of the electrode connection member. FIG. 8 is a schematic diagram showing the flow of current in the fuel cell stack unit.

As shown in FIGS. 6 and 7, the electrode connection member 56 has an attachment portion 56 a that can be attached to the other end 1 b of the fuel cell stack 1, and a connection portion 56 b that extends downward from the attachment portion. doing. The attachment portion 56a has a C-shaped cross-sectional shape that can be fitted so as to tighten the other end portion 1b of the fuel cell stack 1. The connecting portion 56b has a U-shaped cross-sectional shape that can be pressed and bent between the adjacent fuel cell stacks 1. The connecting portion 56b is connected to the interconnector 20 of the first fuel cell 4a of one fuel cell stack 1 adjacent to each other and the current collecting layer 18 of the fourth fuel cell 4d of the other fuel cell stack 1. It is pressed and contacts from one end 1a to the other end 1b. Thereby, the adjacent fuel cell stacks 1 are electrically connected in series and reliably.
Thus, as shown in FIG. 8, the fuel electrode terminal 26u and the air electrode terminal 27u of the fuel cell stack unit 60 are respectively the fuel electrode terminal 26 of the fuel cell stack 1 on one side and the air electrode terminal on the other side. 27, and the current flows along the path indicated by the arrow A1. From the viewpoint of more reliably connecting the electrode connecting member 56 and the fuel cell stack 1, a conductive adhesive or a mixture of silver and glass may be interposed between the electrode connecting member 56 and the fuel cell stack 1. Good.

  The electrode connection member 56 is formed by, for example, sheet metal processing or the like of various metals covered with silver, lanthanum chromite, lanthanum cobaltite, or the like, stainless steel, nickel base alloy, chromium base alloy, or the like. Is preferred. The electrode connecting member 56 is preferably a dense body from the viewpoint that current flows in the thickness direction of the U-shaped portion and from the viewpoint of rectifying the flow of the reaction gas flowing outside the fuel cell stack 1.

  Since the electrode connecting member 56 extends from one end 1a to the other end 1b between the fuel cells 4 facing each other, even if there is a contact failure in a part thereof, the electrical connection of the fuel cell 4 The connection state is maintained, and the reliability of the fuel cell stack unit 50 is improved.

9 and 10 are perspective views showing an embodiment and a modification of the electrode connecting member.

As shown in FIG. 9, the electrode connection member 58 of the embodiment, similar to the connection portion 56b of the electrode member 56, bent to allow the Y-shaped deflection is pressed between the adjacent fuel cell stack 1 metal It is a sheet. The modified electrode connecting member 58 is attached between them by pushing it between adjacent fuel cell stacks 1 and from one end 1a to the other end 1b. From the viewpoint of more reliably connecting the electrode connection member 58 and the fuel cell stack 1, a conductive adhesive or a mixture of silver and glass may be interposed between the electrode connection member 58 and the fuel cell stack 1. Good.

  As shown in FIG. 10, the electrode connection member 60 of the modified example is formed of a material that can be bent and, for example, various metals coated with silver, lanthanum chromite, lanthanum cobaltite, etc., stainless steel, nickel-base alloy It is made of a porous ceramic material such as sponge-like, felt-like or lanthanum chromite of a heat-resistant metal such as a chromium-based alloy. The electrode connection member 60 of the modified example is attached between them by pushing it between the adjacent fuel cell stacks 1 and from one end 1a to the other end 1b. From the viewpoint of more reliably connecting the electrode connecting member 60 and the fuel cell stack 1, a conductive adhesive or a mixture of silver and glass may be interposed between the electrode connecting member 60 and the fuel cell stack 1. Good.

FIG. 11 is a schematic diagram illustrating a current flow in the embodiment of the fuel cell stack unit.

As shown in FIG. 11, in the fuel cell stack unit 62 of the embodiment, the fuel cell stack 30 of a plurality of the first embodiment, one fuel cell stack 40 and the fuel gas in the second embodiment They are fixed on the manifold and are electrically connected in series by the electrode connecting member 58 of the embodiment . Specifically, the electrode connection member 58 includes the air electrode terminal 27a of the first series connection cell group 24b of one fuel cell stack 30 adjacent to each other and the first series connection cell of the other fuel cell stack 30 . It is pressed against and in contact with the fuel electrode terminal 26a of the group 24b. In addition, the electrode connection member 58 includes the fuel electrode terminal 26b of the second series connection cell group 24c of one fuel cell stack 30 adjacent to each other and the second series connection cell group 24c of the other fuel cell stack 30 . It is pressed against and in contact with the air electrode terminal 27b. Thus, the current flows along the path indicated by the arrow A2 shown in FIG.

In this case, the fuel electrode terminal 26u and the air electrode terminal 27u of the fuel cell stack unit 62 are each located farthest from the fuel cell stack 40 of the second embodiment, and the fuel cell stack 30 of the first embodiment. Fuel electrode terminal 26a and air electrode terminal 27b. Accordingly, the wiring work to the fuel electrode terminal 26u and the air electrode terminal 27u becomes common regardless of the number of the fuel cell stacks 30, so that the work when assembling the fuel cell stack 30 and increasing / decreasing the number of the fuel cell stacks 30 are performed. It becomes easy.

Next, an embodiment of the fuel cell stack unit will be described. FIG. 12 is a perspective view of an embodiment of a fuel cell stack unit according to the present invention.

The fuel cell stack unit 70 according to the embodiment of the present invention includes a fuel gas manifold 72 and four fuel cell stacks 76 disposed on the side surfaces 72a and 72b.

The fuel cell stack 76 is a modification of the fuel cell stack 1 of the reference example described above, except that the number of the fuel cells 4 arranged in each of the planar portions 10a and 10c is five. It has the same structure as the stack 1.

  The fuel gas manifold 72 is a horizontally long rectangular parallelepiped sealed box, and has a fuel gas space 74 filled with fuel gas therein. In the fuel gas space 74, the hole 8 of each fuel cell stack 76 and the fuel gas space 74 communicate with each other. Fuel gas is supplied to the fuel gas space 74 from a fuel gas supply pipe (not shown). The fuel gas supply pipe (not shown) is preferably connected to a reformed gas apparatus (not shown).

The two fuel cell stacks 76 are airtightly fixed to one side surface 72a of the fuel gas manifold 72 using brazing or glass so that one flat surface portion 10a and the other flat surface portion 10b face each other. ing. The other two fuel cell stacks 76 are brazed or glass-sealed to the other side surface 72b of the fuel gas manifold 72 so that the one plane portion 10a and the other plane portion 10b face each other. It is fixed to.
Adjacent fuel cells 76 are electrically connected in series via the electrode connecting members 58 and 60 (not shown) described above.

  The fuel cell stack unit 70 enables the arrangement of the fuel cell stack having a small vertical dimension.

Next, an example of a fuel cell using the fuel cell stack unit of the reference example will be described. FIG. 13 is a schematic front view of a first embodiment of a fuel cell according to the present invention.

  As shown in FIG. 13, the fuel cell 80 according to the first embodiment of the present invention includes the above-described fuel cell stack unit 50 (in FIG. 13, the number of fuel cell stacks 1 is omitted as six). And a case 81 for housing it. The fuel gas H is supplied from the outside of the case 81 to the fuel gas manifold 52 through the reformer 82 disposed in the case 81, and the inside of the fuel cell stack 1 is moved from one end 1a to the other end 1b. It flows toward. The air O flows from the outside of the case 91 through the outsides of the fuel cell stack 1 through the passages 93 and 94 provided in the case 91. From the viewpoint of obtaining a uniform current distribution, the air is preferably blown from below the fuel cell stack 1 and flows outside the tube of the fuel cell stack 1 from below to above. By blowing air from the lower side of the fuel cell stack 1, an effect of cooling the lower side of the fuel cell stack 1 is obtained. That is, the current distribution that tends to concentrate below the fuel cell stack 1 can be spread throughout the fuel cell stack 1 due to the temperature difference. Thus, the fuel gas H and the air O are mixed and burned in the combustion region 85 adjacent to the other end 1b of the fuel cell stack 1, and the combustion gas C generated thereby is provided in the case 81. It is discharged from the discharge port 97 through the passage 96. The reformer 92 is preferably disposed in the combustion region 85 in order to use heat generated by the combustion of the fuel gas H and air O.

Next, an example of a fuel cell using the fuel cell stack unit embodiment will be described. FIG. 14 is a schematic plan view of a second embodiment of the fuel cell according to the present invention.

  As shown in FIG. 14, the fuel cell 90 according to the second embodiment of the present invention is provided on the above-described fuel cell stack unit 70 (in FIG. 14, one planar portion 10a of the fuel cell stack 70). The number of the fuel battery cells 4 is omitted in two, and a case 91 is provided. The fuel gas H is supplied from the outside of the case 91 to the fuel gas manifold 72 through the reformer 92 disposed in the case 91, and the inside of the fuel cell stack 76 is changed from one end 1a to the other end 1b. It flows toward. The air O is supplied from the outside of the case 91 to the air manifold 94 through the air heat exchanger 93 disposed in the case 91 and flows over the entire outside of the fuel cell stack 76. The fuel gas H and the air O are mixed and burned in the combustion region 95 adjacent to the other end 1 b of the fuel cell stack 76, and the combustion gas C generated thereby is discharged from an outlet provided in the case 91. It is discharged from 96. The reformer 92 and the air heat exchanger 93 are preferably arranged in the combustion region 95 in order to use heat generated by the combustion of the fuel gas H and the air O.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the invention described in the claims. Needless to say, these are also included within the scope of the present invention.

  In the above embodiment, the gas flowing inside the tubular portion 6 of the fuel cell 4 is a fuel gas such as reformed gas obtained by reforming hydrogen or hydrocarbon fuel, and the outside of the tubular portion 6 of the fuel cell 4. The gas flowing through the air was air containing oxygen, but the gas flowing inside may be exchanged with the gas flowing outside.

  Moreover, in the said embodiment, although the cross section of the fuel cell 4 was flat shape, cross-sectional shape is arbitrary and an elliptical flat tube shape may be sufficient.

  The shape and number of the fuel cells 4 provided in the fuel cell stack 1 are arbitrary. Accordingly, the fuel cell stack 1 may be vertically long or horizontally long when the in-pipe gas flow direction F is regarded as the vertical direction. In the case of being vertically long, it is suitable for increasing the current, that is, for increasing the area of the fuel cell 4. Further, in the case of landscape, it is preferable when it is desired to increase the voltage, that is, when the number of fuel cells 4 is increased.

DESCRIPTION OF SYMBOLS 1, 30, 40 Fuel cell stack 1a One edge part 1b The other edge part 2 Base | substrate 4, 4a-4d Fuel cell 6 Tubular part 10a, 10c Planar part 10b, 10d Connection surface part 12a-12d Fuel electrode 14 ( 14a-14d) Electrolytes 16a-16d Air electrodes 18a-18d Current collecting layers 20a-20d Interconnectors 22, 23 Extended current collecting layers 24a-24d Series connected cell groups 50, 70 Fuel cell stack units 52, 72 Fuel gas manifold 80 , 90 Fuel cell 81, 91 Case

Claims (3)

A fuel cell stack unit in which a plurality of fuel cell stacks in which a plurality of fuel cells are stacked on a substrate are electrically connected, wherein the substrate extends in the longitudinal direction and has a cross section perpendicular to the longitudinal direction in width. A fuel cell stack having a shape with a small thickness and having a hole penetrating from one end to the other end along the longitudinal direction inside the fuel cell, each of which includes a fuel electrode, an electrolyte, and an air electrode In the unit
One of air and fuel gas flows from one end of the hole in the base to the other end, and the other of air and fuel gas flows outside the fuel cell stack,
Each of the fuel cell stacks has a fuel electrode terminal and an air electrode terminal electrically connected to the fuel electrode and the air electrode of the fuel cell,
The base body includes a first peripheral surface portion and a second peripheral surface portion located on opposite sides in the thickness direction of the base body, and a first peripheral surface portion and a second peripheral surface located on opposite sides in the width direction of the base body. Having a peripheral surface composed of a first connecting surface portion and a second connecting surface portion connecting the portions;
Each of the fuel cell stacks is electrically connected to the fuel electrode terminal and the air electrode terminal of each of the fuel cell stacks, and is separated along the first peripheral surface portion or the second peripheral surface portion of the base. Are connected in series with each other via a plurality of electrode connection portions provided, and the plurality of electrode connection portions are provided near the center of the fuel cell stack of the fuel cell . A fuel cell stack unit characterized by that. 2. The fuel cell stack unit according to claim 1, wherein the plurality of electrode connection portions are provided across a central portion of the first peripheral surface portion or the second peripheral surface portion of the base body. Each of the fuel cell stacks flows a current along the first connection surface portion from the fuel electrode terminal on the first peripheral surface portion side of the base toward the air electrode terminal on the second peripheral surface portion side, fuel cell according to claim 1 or 2 is configured to flow the current along the from the circumferential portion of the fuel electrode terminal toward the first peripheral portion side of the air electrode terminal second connecting surface portion Stack unit.

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