JP2021022476A - Cell stack device, fuel cell module, and fuel cell device - Google Patents

Abstract

To provide a cell stack device that can efficiently draw a large current from a fuel cell stack.SOLUTION: A cell stack device includes a cell stack in which fuel cell cells are arranged and electrically connected to each other, and a pair of conductive members 10 located at both ends of the cell stack in the arrangement direction x of the fuel cell, and electrically connected to the fuel cell. The conductive member 10 includes a power receiving unit 10a facing the cell stack, and a current extraction unit 10b extending outward from the power receiving unit 10a. The current extraction unit 10b includes an extraction unit main body, and a connection unit connected to an external device, and the ratio of the average width W1 of the extraction unit main body to the average W0 of the width of the power receiving unit 10a is 1/3 or more.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to a cell stack device, a fuel cell module, and a fuel cell device formed by electrically connecting a plurality of fuel cell cells.

In recent years, as a next-generation energy, a fuel cell device in which a cell stack device is stored in a storage container has been proposed (see, for example, Patent Document 1).

In the cell stack device, a plurality of fuel cell cells are arranged in a state of being erected via a current collecting member, and conductive members are arranged at both ends in the arrangement direction via the end current collecting member to fuel. The lower end of the battery cell and the lower end of the conductive member are fixed to the gas tank.

The conductive member includes a power receiving portion joined to the end current collecting member, and a current drawing portion integrally provided with the power receiving portion and extending outward along the arrangement direction of the fuel cell. The power receiving portion has a plurality of plate-shaped portions and a connecting portion that connects these plate-shaped portions, and the connecting portion has a width shorter than that of the plate-shaped portion.

JP-A-2010-129270

An object of the present disclosure is to provide a cell stack device, a fuel cell module, and a fuel cell device capable of efficiently extracting a large current from a fuel cell.

The cell stack device of the present disclosure is located at both ends of a cell stack formed by arranging and electrically connecting fuel cell cells and the cell stack in the arrangement direction of the fuel cell, and is electrically connected to the fuel cell. It includes a pair of conductive members connected to the. The conductive member includes a power receiving portion facing the cell stack and a current drawing portion extending outward from the power receiving portion. The current extraction unit has a extraction unit main body and a connection unit connected to an external device, and the ratio of the average width of the extraction unit body to the average width of the power receiving unit is 1/3 or more.

The fuel cell module of the present disclosure comprises the above-mentioned cell stack device housed in a storage container.

The fuel cell device of the present disclosure includes the above fuel cell module housed in an outer case.

According to the present disclosure, it is possible to provide a cell stack device, a fuel cell module, and a fuel cell device capable of efficiently extracting a large current from a fuel cell.

The upper part is a side view schematically showing one of the examples of the cell stack device, and the lower part is an enlarged cross-sectional view of a part of the part surrounded by the broken line of the cell stack device shown in the upper part. It is a perspective view which shows one of the examples of a conductive member. It is a top view which shows one of the examples of a current drawing part. It is a top view which shows one of the examples of a conductive member. It is an external perspective view which shows an example of a fuel cell module. It is an exploded perspective view which shows an example of a fuel cell apparatus.

The upper part of FIG. 1 is a side view schematically showing the cell stack device 1, and the lower part of FIG. 1 is an enlarged cross-sectional view of a part of the cell stack device 1 in the upper part of FIG. 1 surrounded by a broken line. .. The same members are designated by the same reference numerals, and the same applies hereinafter. The correspondence between the portion surrounded by the broken line in the upper part of FIG. 1 and each figure in the lower part of FIG. 1 is indicated by an arrow.

The cell stack device 1 includes a fuel cell 2 and a gas tank 3. The lower end of the fuel cell 2 is joined and fixed to the opening of the gas tank 3 with an electrically insulating sealing material S. The gas tank 3 supplies fuel gas to the fuel cell 2.

The fuel cell 2 includes a first electrode layer, a solid electrolyte layer, and a second electrode layer on one of the pair of opposing flat surfaces of the columnar conductive support 4. The power generation element 5 is a portion of the fuel cell 2 in which the solid electrolyte is sandwiched between the first electrode layer and the second electrode layer. An interconnector 6 is provided on the other flat surface of the pair of flat surfaces of the support 4, and the conductive support 4 has a plurality of gas flow paths 7 that allow gas to flow through the power generation element 5 inside. have. Hereinafter, the conductive support 4 may be abbreviated as the support 4.

The cell stack 8 has a plurality of fuel cell cells 2 erected and arranged, and a current collecting member 9a for electrically connecting adjacent fuel cell cells 2 in series. The direction in which the plurality of fuel cell cells 2 are arranged is referred to as the arrangement direction x.

The cell stack device 1 includes end current collecting members 9b at both ends of the cell stack 8 in the arrangement direction x, and conductive members 10 on the outer side thereof. The lower end of the conductive member 10 may be fixed to the gas tank 3 with the sealing material S. The conductive member 10 may be integrated with the end current collector member 9b.

Hereinafter, unless otherwise specified, the first electrode layer in contact with the support 4 will be referred to as a fuel electrode, and the second electrode layer located outside the fuel cell 2 will be referred to as an air electrode. The first electrode layer may be an air electrode and the second electrode layer may be a fuel electrode.

The fuel cell 2 may not form the first electrode layer, and the support 4 may be a fuel electrode or an air electrode. For example, the fuel cell 2 may include a solid electrolyte layer and a second electrode layer on one of the pair of flat surfaces of the support 4.

The fuel cell 2 may be, for example, a solid oxide fuel cell 2. The solid oxide fuel cell 2 has high power generation efficiency, and the fuel cell device can be miniaturized. Further, the solid oxide fuel cell 2 can perform load following operation, and can follow the fluctuating load required for, for example, a household fuel cell.

Hereinafter, each member constituting the cell stack device 1 shown in FIG. 1 will be described.

As the fuel electrode, a material generally known as the fuel electrode may be used. The fuel electrode may be formed from porous conductive ceramics such as stabilized zirconia and Ni and / or NiO. Stabilized zirconia is ZrO ₂ in which rare earth elements are dissolved, and also includes partially stabilized zirconia.

The solid electrolyte layer is an electrolyte that bridges electrons between electrodes. The solid electrolyte layer has a gas blocking property so that the fuel gas and the oxygen-containing gas such as air do not mix with each other. The material of the solid electrolyte layer is not particularly limited as long as it is an electrolyte having a gas blocking property, and may be, for example, ZrO ₂ in which 3 mol% to 15 mol% of a rare earth element is solid-solved.

As the air electrode, a material generally used as an air electrode may be used. The air electrode may be formed of, for example, conductive ceramics made of so-called ABO- ₃ type perovskite type oxide. The air electrode has gas permeability. The porosity of the air electrode may be 20% or more, particularly in the range of 30% to 50%.

The material of the interconnector 6 may be conductive ceramics. The interconnector 6 comes into contact with a fuel gas such as a hydrogen-containing gas and an oxygen-containing gas such as air. Therefore, as the material of the interconnector 6, a lanthanum chromite-based perovskite-type oxide (LaCrO _3- based oxide) having reduction resistance and oxidation resistance may be used. The interconnector 6 is dense so that the fuel gas flowing through the gas flow path 7 formed in the support 4 and the oxygen-containing gas flowing outside the fuel cell 2 are not mixed, and the interconnector 6 is 93% or more. In particular, it may have a relative density of 95% or more.

The support 4 has gas permeability and conductivity. Since the support 4 has gas permeability, the fuel gas flowing through the gas flow path 7 of the support 4 can reach the first electrode layer of the fuel electrode. Since the support 4 has conductivity, the electricity generated by the power generation element 5 can be collected via the interconnector 6. As the material of the support 4, for example, conductive ceramics, cermet, or the like may be used. When the support 4 is produced by co-fired with the fuel electrode or the solid electrolyte layer, the material of the support 4 may be a material containing an iron metal component and a specific rare earth oxide. The open porosity of the support 4 may be, for example, 30% or more, particularly in the range of 35 to 50%. When the support 4 has such an open porosity, the fuel gas flowing through the gas flow path 7 of the support 4 can reach the first electrode layer of the fuel electrode. The conductivity of the support 4 may be, for example, 300 S / cm or more, particularly 440 S / cm or more.

In the fuel cell 2 shown in FIG. 1, the columnar support 4 is a plate-shaped piece extending in the longitudinal direction z of the fuel cell 2, and has a pair of opposing flat surfaces and a pair of semicircular side surfaces. It has a hollow flat plate shape. A coating layer 11 having a gas blocking property, such as the same material as the solid electrolyte layer, is provided on a portion such as the side surface of the support 4 that does not have the power generation element 5 and the interconnector 6. The lower end of the fuel cell 2 is fixed to the opening of the gas tank 3 with a sealing material S such as a glass sealing material having excellent heat resistance. The gas flow path 7 of the support 4 leads to a fuel gas chamber (not shown).

A current collecting member 9a is arranged between the adjacent fuel cell cells 2. The current collecting member 9a electrically connects two adjacent fuel cell cells 2 in series. The end current collecting members 9b are arranged at both ends of the cell stack 8 in the arrangement direction x. The current collecting member 9a and the end current collecting member 9b may be joined to the fuel cell 2 with a conductive adhesive. As the material of the current collecting member 9a and the end current collecting member 9b, an elastic metal or alloy may be used, or a felt made of metal fibers or alloy fibers may be used. Felt made of metal fibers or alloy fibers may be surface-treated, if necessary. The same member may be used for the current collecting member 9a and the end current collecting member 9b. As the end current collecting member 9b, a member that is more easily deformed than the current collecting member 9a may be used.

FIG. 2 is a perspective view showing one of the examples of the conductive member 10. The conductive member 10 includes a plate-shaped power receiving portion 10a joined to the end current collecting member 8b, a flat plate-shaped current drawing portion 10b extending outward from the power receiving portion 10a along the arrangement direction x of the fuel cell 2. It is provided with a fixing portion 10c fixed to the gas tank 3 at the lower end. In addition, in FIG. 1, in order to make it easy to understand the conductive member 10, it is shown by drawing diagonal lines.

A through hole 12 is provided at the end of the current extraction portion 10b in the arrangement direction x, and a current extraction cable from an external device (not shown) is connected to the through hole 12 with a bolt or the like. Hereinafter, the current extraction cable may be simply referred to as a cable.

In such a cell stack device 1, the larger the cross-sectional area of the cable and the current extraction portion 10b, the larger the current taken out from the cell stack device 1.

FIG. 3 is a plan view showing one of the examples of the current extraction unit 10b. The current extraction portion 10b shown in FIG. 3 has a extraction portion main body 10b1 and a connection portion 10b2 located outside the extraction portion main body 10b1 in the arrangement direction x and having a through hole 12. In other words, the extraction portion main body 10b1 is a portion of the current extraction portion 10b located between the power receiving portion 10a and the through hole 12.

When the average width of the power receiving unit 10a is W0 and the average width of the drawer main body 10b1 is W1, the ratio of W1 to W0 is 1/3 or more, that is, W0 is 3 times or less of W1. By setting the ratio of W1 to W0 to 1/3 or more, the cross-sectional area of the drawer portion main body 10b1 can be increased, and the electrical resistance of the drawer portion main body 10b1 becomes small. As a result, even if a large current flows from the cell stack 8 to the drawer portion main body 10b1, the cross-sectional area of the drawer portion main body 10b1 is large, so that the current loss in the drawer portion main body 10b1 can be reduced. This makes it possible to efficiently draw a large current from the fuel cell.

W1 may be W0 or less. When W1 is W0 or less, it is possible to reduce the concern that the drawer portion main body 10b1 and other parts of the cell stack device 1 or peripheral members come into contact with each other to cause a short circuit. The thickness of the drawer portion 10b1 may be thicker than the thickness of the power receiving portion 10a.

As the material of the conductive member 10, for example, a material having conductivity such as a heat-resistant alloy may be used. By using a conductive material for the conductive member 10, the current generated by the power generation of the fuel cell 2 can be collected. If necessary, the conductive member 10 may be made of a material having a heat-resistant film on its surface.

The current extraction unit 10b may be appropriately arranged according to the shape of the fuel cell 2 and the like. In the example of FIG. 2, the current extraction unit 10b is arranged below the power receiving unit 10a according to the shape of the columnar fuel cell 2 shown in FIG. The fuel cell 2 may have a cylindrical shape or a flat plate shape. The cell stack 8 may be a stack of flat fuel cell cells 2. In FIG. 2, the current extraction portion 10b extending along the arrangement direction x is shown. For example, in the case of the cell stack 8 in which the flat plate-shaped fuel cell 2 is laminated, the current extraction portion 10b extends in the y direction or the z direction. You may.

As shown in FIG. 3, the connecting portion 10b2 may have a width smaller than that of the drawer portion main body 10b1. Since the width of the connecting portion 10b2 is smaller than that of the drawer portion main body 10b1, the degree of freedom of connection with the cable is increased.

The upper end of the power receiving portion 10a of the conductive member 10 in the longitudinal direction z may be arranged at the same position as the upper end of the fuel cell 2 or at a position higher than the upper end of the fuel cell 2 while being fixed to the gas tank 3. .. By setting the upper end of the power receiving unit 10a to the same position as the upper end of the fuel cell 2 or a position higher than the upper end of the fuel cell 2, the stress generated in the fuel cell 2 can be relaxed and the fuel cell 2 can be relaxed. The current generated by the power generation of the above is efficiently collected in the power receiving unit 10a. The width of the conductive member 10 may be the same as the width of the power generation element 5 and the width of the interconnector 6, whichever is shorter, or may be larger than that. The width of the conductive member 10 may be the same as or larger than the width of the fuel cell 2.

As shown in FIG. 4, the power receiving unit 10a may have a first portion 13 having a narrow width. The first portion 13 has lower rigidity than the other portions of the power receiving portion 10a and is easily deformed. The cell stack device 1 having such a power receiving unit 10a can absorb the displacement of the fuel cell 2 or the displacement of the cell stack 8 at the first portion 13, and has an influence on the sealing property around the cable in the storage container. Can be reduced. The first portion 13 may be arranged in the vicinity of the current extraction portion 10b. When the first portion 13 is arranged close to the current extraction portion 10b, the through hole 12 of the connection portion 10b2 is fixed to the current extraction cable, and the first portion 13 is vertically z and / or horizontal to the current extraction portion 10b. When a displacement in the direction, particularly a displacement in the width direction y in the horizontal direction occurs, the displacement is easily absorbed by the first portion 13, and the displacement of the through hole 12 located at the tip of the current extraction portion 10b can be suppressed. As a result, it is possible to reduce an adverse effect on the sealing property around the cable in the storage container.

Although not shown, the first portion 13 may have a portion that overlaps with the drawer portion main body 10b1 when the conductive member 10 is viewed from the side in the y direction.

The width of the first portion 13 may be appropriately set according to the width of the power receiving portion 10a so as to be more easily deformed than the portions other than the first portion 13. The width of the first portion 13 may be smaller than W0. Further, the width of the first portion 13 may be larger than, for example, W1.

The thickness of the first portion 13 may be the same as that of other portions of the power receiving portion 10a. The thickness of the first portion 13 may be thicker than that of other portions of the power receiving portion 10a. When the thickness of the first portion 13 is thicker than that of the other portions of the power receiving portion 10a, a larger current can be taken out even if the width of the first portion 13 is narrow. The thickness of the first portion 13 may be thinner than that of the other portions of the power receiving portion 10a. When the thickness of the first portion 13 is thinner than that of the other portions of the power receiving portion 10a, it becomes easier to absorb the displacement in the stacking direction x.

FIG. 5 shows a fuel cell module 20 in which a cell stack device 1 is housed inside a rectangular parallelepiped storage container 21. The fuel cell module 20 of FIG. 5 includes a reformer 22 arranged above the cell stack 2 and a gas flow pipe 23 connecting the reformer 22 and the gas tank 3. The reformer 22 reforms raw fuels such as natural gas and kerosene to generate fuel gas. The gas flow pipe 23 supplies the fuel gas reformed by the reformer 22 to the gas tank 3. The fuel gas is supplied from the gas tank 3 to the gas flow path 7 inside the fuel cell 2.

FIG. 5 shows a state in which the front surface and the rear surface, which are a part of the storage container 21, are removed, and the cell stack device 1 housed inside is taken out to the rear. The fuel cell module 20 shown in FIG. 5 can slide and store the cell stack device 1 in the storage container 21. The cell stack device 1 does not have to include the reformer 22.

The storage container 21 is provided with an oxygen-containing gas introducing member 24 inside. The oxygen-containing gas introduction member 24 of FIG. 5 is arranged between the cell stacks 2 in a state where the cell stack device 1 is housed in the storage container 21. The oxygen-containing gas introduction member 24 supplies the oxygen-containing gas to the lower end of the fuel cell 2. The oxygen-containing gas flows by the oxygen-containing gas introducing member 24 from the lower end to the upper end on the side of the fuel cell 2 in accordance with the flow of the fuel gas. The fuel gas discharged from the gas flow path 7 of the fuel cell 2 to the upper end of the fuel cell 2 is mixed with the oxygen-containing gas and burned. By burning the fuel gas discharged at the upper end of the fuel cell 2, the temperature of the fuel cell 2 rises, and the start of the cell stack device 1 can be accelerated. Further, when the fuel gas burns at the upper end of the fuel cell 2, the reformer 22 arranged above the fuel cell 2 is warmed, and the reformer 22 can efficiently perform the reforming reaction. it can.

FIG. 6 is an exploded perspective view showing an example of the fuel cell device 30. In FIG. 6, some configurations are omitted.

In the fuel cell device 30 shown in FIG. 6, the inside of the exterior case having the support column 31 and the exterior plate 32 is vertically partitioned by the partition plate 33. The upper side of the outer case is a module storage chamber 34 for storing the above-mentioned fuel cell module 20. The lower side inside the outer case is an auxiliary equipment storage chamber 35 for storing auxiliary equipment for operating the fuel cell module 20. The description of the auxiliary equipment to be stored in the auxiliary equipment storage chamber 35 is omitted.

The partition plate 33 is provided with an air flow port 36. The air in the auxiliary machine storage chamber 35 flows to the module storage chamber 34 through the air flow port 36. An exhaust port 37 is provided in a part of the exterior plate 32 that constitutes the module storage chamber 34. The air in the module storage chamber 34 is exhausted from the exhaust port 37.

As described above, the fuel cell device 30 includes the fuel cell module 20 capable of improving the power generation efficiency in the module storage chamber 34, so that the fuel cell device 30 can be the fuel cell device 30 having improved power generation efficiency.

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

For example, in the fuel cell stack device 1 described above, an example is shown in which fuel gas is supplied to the gas flow path 7 in the fuel cell 2 and oxygen-containing gas is supplied to the outside of the fuel cell 2. An oxygen-containing gas may be supplied to the gas flow path 7, and the fuel gas may be supplied to the outside of the fuel cell 2.

1: Cell stack device 2: Fuel cell 3: Gas tank 4: Conductive support 5: Power generation element 6: Interconnector 7: Gas flow path 8: Cell stack 9a: Current collecting member 9b: End current collecting member 10: Conductive member 10a: Power receiving part 10b: Current drawing part 11: Dense coating layer 12: Through hole 13: First part 20: Fuel cell module 30: Fuel cell device

Claims (7)

A cell stack consisting of arranging fuel cell cells and electrically connecting them,
A pair of conductive members located at both ends of the cell stack in the arrangement direction of the fuel cell and electrically connected to the fuel cell are provided.
The conductive member includes a power receiving portion facing the cell stack and a current drawing portion extending outward from the power receiving portion.
The current extraction unit has a connection unit connected to the extraction unit main body and an external device, and also has a connection unit.
A cell stack device in which the ratio of the average width of the drawer unit body to the average width of the power receiving unit is 1/3 or more. The cell stack device according to claim 1, wherein the average width of the drawer portion main body is equal to or less than the average width of the power receiving portion. The cell stack device according to claim 1 or 2, wherein the power receiving unit has a narrow first portion. The cell stack device according to claim 3, wherein the first portion has a portion that overlaps with the main body of the drawer portion in a side view of the conductive member. The cell stack device according to claim 3 or 4, which has two or more of the first parts. A fuel cell module in which the cell stack device according to any one of claims 1 to 5 is stored in a storage container. A fuel cell device in which the fuel cell module according to claim 6 is housed in an outer case.

Images