JPH01267964A - Fuel battery with solid electrolyte - Google Patents

Abstract

PURPOSE:To increase the number of unitary cells per unit area and raise the output density in power generation by arranging a number of unitary cells concentrically, and forming a fuel battery stack. CONSTITUTION:Each unitary cell is composed of a base tubing 1 consisting of a bottomed cylinder made in porous substance, an oxygen side electrode 3 in the form of laminate on the outer surface of this base tubing 1, and a fuel side electrode 4. Thus a number of unitary cells 5a-5d are made by the use of base tubings with different dias. and heights, and the shape of each unitary cell is in a cylinder with its one end closed, and they can be arranged concentrically by varying the dia. and height steppedly. Thus the number of unitary cells per unit area is increased, and the output density in power generation raised.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a solid oxide fuel cell, and particularly to a solid oxide fuel cell with a high power generation output density.

[Prior Art] Fuel cells, which have recently attracted attention as a low-pollution energy source, generate electrical energy by continuously supplying fuel as an active material and oxidizing agent from the outside, which are the sources of electromotive reactions. This is a battery that can take out the reaction products as well as continuously discharge the reaction products. Among these types of fuel cells, solid oxide fuel cells are attracting attention because they have no fear of electrolyte leakage and have a high reaction rate. It is known that a large number of sequentially stacked single cells are arranged on a substrate. Examples of such prior art include Japanese Patent Application Laid-Open No. 101971/1983.

[Problem to be solved by the invention]

However, in the above-mentioned conventional technology, a large number of single cells are arranged on a substrate, and the electrodes of each single cell are connected in series or parallel with interconnectors, etc., and a large substrate area is required for arranging the single cells. In addition, there was a problem that the power generation output per unit area, that is, the power generation output density was low.

An object of the present invention is to solve the problems of the prior art described above and to provide a solid oxide fuel cell with high power generation output density.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a single cell substrate in which an oxygen electrode made of a one-electron conductor, an oxygen ion conductive solid electrolyte, and a fuel electrode made of an electron conductor are laminated on a gas-permeable base tube. In the solid oxide fuel cell arranged in large numbers on the top, the base tube is formed into a cylindrical shape with one end closed, and the diameter and height of the base tube are changed in stages to constitute a single cell,
It is characterized by having a large number of these single cells arranged concentrically.

[Effect]

−・Single cells were created by changing the diameter and height of a cylindrical base tube with a closed end in stages, and the single cells were arranged concentrically on a substrate to form a fuel cell stack. As a result, the number of single cells per unit area of the substrate increases, and the power generation output density of the solid oxide fuel cell as a whole increases.

In the present invention, the solid electrolyte having electronic conductivity includes, for example, a fluorite-type oxide in which a divalent or trivalent metal oxide is dissolved in a tetravalent metal oxide, and a typical example is Zr.
0z Yz 03 (YSZ), CeO□-CaO
etc. are known. In addition, the electronic conductor used as the oxygen electrode or fuel electrode is chemically stable at high temperatures of around 1000°C, has a coefficient of thermal expansion close to that of the solid electrolyte, and has electronic conductivity. As an oxygen electrode, for example, LaCo0=, L, which is stable in a high temperature oxygen atmosphere.
Composite oxides such as aCr(h) can be used as fuel electrodes, such as CoN i -Z ro□, N
+ -A1 etc. are mentioned.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples.

FIG. 1A is a sectional view of a single cell constituting a solid oxide fuel cell showing one embodiment of the present invention, and FIG. 1B is a detailed view of the opening shown in FIG. 1A. This single cell consists of a bottomed cylindrical porous base tube l, and a lanthanum-based material such as LaCo, which is sequentially laminated on the outer surface of the base tube l on a thin film.
Q, an oxygen electrode (hereinafter referred to as the oxygen side electrode) 3, B
i, 0yYzox system, for example (Y-Ox). ,zs
(BizO, +). , ヮ, and a nickel-based fuel electrode (for example, N1p-YSZ).
(hereinafter referred to as the fuel side electrode) 4. Near the opening of the single cell, in order to efficiently take out the generated electrical energy, there is a part where the surface of the base tube I is exposed and where nothing is laminated, and an outer surface half around the circumference of the circle with a circular cross section. In the remaining half of the laminated electrode material, a portion is provided in which the electrode material laminated on the inner surface is extended and individually laminated. The stacking positions of the oxygen-side electrode 3 and fuel-side electrode 4 that are stacked on a single cell differ depending on the arrangement position of the single cell in the fuel cell stack. A side electrode 3 and a fuel side electrode 4 are laminated on the inner surface, respectively, and when the outer surface of the unit cell becomes a fuel flow path, the fuel side electrode 4 is laminated on the outer surface and the oxygen side electrode 3 is laminated on the inner surface. A large number of such single cells are created using base tubes of different diameters and heights, and these are combined to form a fuel cell stack.

FIG. 2 is an explanatory diagram of a fuel cell stack showing one embodiment of the present invention in which a large number of single cells are combined, and FIGS. 3A and 3B are respectively the tube arrangement directions of the air supply pipes 7 in FIG. 2. FIG. 2 is a cross-sectional view of FIG.

3A and 3B, this fuel cell stack has a flange vi made of electrically insulating ceramics.
6, and a single cell 5 fitted concentrically into the flange plate 6.
a, 5b, 5C and 5d, an air supply pipe 7, which is branched from the air supply pipe 7 and passes through the flange plate 6, into the base pipe 1 of the single cell 5a and between the single cells 5b and 50. An air pipe 8 that sends air, a fuel feed pipe 9, and a pipe branched from the fuel feed pipe 9 and passing through the partition wall 11 and temporary flange 6 marked 11) between the single cells 5a and 5b and between the single cells 5C. 5d, and a fuel pipe 10 that sends fuel during each period. Both the air pipe 8 and the fuel diagonal pipe 10 have their tips extending to the tips of each single cell in order to send air and fuel to the tips of the single cells, and the partition wall I″l of the fuel pipe IO and the flange plate 6 The space between the air supply pipe 7 and the fuel supply pipe 9 is a double pipe, with the inner pipe serving as a fuel supply passage and the outer pipe serving as a fuel return passage. The air layer and the fuel layer are separated from each other.
is a fuel hole provided in the outer tube of the fuel pipe 10.

In such a configuration, the air supply pipe 7 and the air pipe 8
through the base tube 1 of the single cell 5a and the single cells 5b and 50.
The air A supplied during this period fills the base tube 1 of the unit cell 5a and the space between the unit cells 5b and 50, and then flows out of the unit cell through the gap between the flange plate 6 and the air tube 8. On the other hand, the single cells 5a and 5
fuel fed between b and between single cells 5c and 5d,
For example, after hydrogen F fills the space between each single cell, it passes between the flange plate 6 and the fuel pipe 100, flows through the outer pipe of the double pipe fuel pipe 1o, and flows through the partition wall 11 for fuel delivery. It flows out to the supply pipe 9 side. An electrode reaction occurs between the electrodes of each single cell to which air A and hydrogen F are supplied in this manner. For example, at the oxygen side electrode 3 on the outer surface of the single cell 5b facing the flow path of air A, oxygen in the air A receives and takes electrons from an external circuit to become oxygen ions, and the solid electrolyte layered inside 2 and becomes a charge carrier. On the other hand, this single cell 5
The inside of the base tube 1 of b becomes a flow path for hydrogen F, which is a fuel, and the hydrogen F flows through the base tube 1 to the fuel-side electrode 4 laminated on its outer surface, where it is absorbed into the solid electrolyte f2. It reacts with oxygen ions to produce water and releases electrons to the outside. Similar electrode reactions occur in other single cells to generate electrical energy, which is collected by the conductive material in the flange plate 6, and then
taken outside. Note that the outer side of the single cell 5d is the partition wall 1.
This is an air layer separated from the fuel layer by 1, and oxygen in this air layer is taken into the oxygen side electrode 3 on the outer surface of the single cell 5d. Further, the fuel hole 12 provided in the outer tube of the fuel tube 10 allows a portion of surplus fuel that is not used for the electrode reaction to leak into the air layer from the fuel hole 12 and burn, raising the air temperature to a high temperature. It is intended to be maintained.

FIGS. 4A and 4B are explanatory diagrams showing the arrangement of the current collecting conductive material on the flange plate 6 and the method of connecting the conductive materials. The current collecting conductive materials 3 are arranged concentrically, and FIG. 4A shows a series connection, and FIG. 4B shows a parallel connection. The electrical energy generated in each unit cell is collected by a current collecting conductive material 13 deposited on the flange plate 6 that supports the unit cell, and then taken out to the outside. Note that the method of connecting the current collecting conductive material 13 can be arbitrarily selected within each fuel cell stack.

According to this example, the shape of the single cell is cylindrical with one end closed, and the diameter and height are changed in stages, so that a large number of single cells can be combined concentrically, and the single cell per unit area is The number increases, and the power generation output density increases.

In addition, unnecessary contact between the fuel and air is avoided by the partition wall 11, and a portion of the fuel leaks to the air side from the fuel hole I2, so that the temperature of the air is maintained at a high temperature by burning this fuel. It can improve fuel utilization.

〔Effect of the invention〕

According to the present invention, since a fuel cell stack is constructed by arranging a large number of single cells concentrically, the number of single cells per unit area increases, resulting in a high power generation output density.

[Brief explanation of the drawing]

FIG. 1A is a sectional view of a single cell constituting a solid oxide fuel cell showing one embodiment of the present invention, FIG. 1B is a detailed view of a portion of FIG. 1A, and FIG. 2 is an embodiment of the present invention. Explanatory diagram of a fuel cell stack of a solid oxide fuel cell showing an example, No. 3A
Figure 3B is a sectional view of Figure 2 and Figure 4A, respectively.
4B and 4B are diagrams each showing an example of a method for connecting a conductive material for current collection deposited on a flange plate of a fuel cell stack. 5a to 5d... Single cell, 6... Flange plate, 7...
- Air supply pipe, 9... Fuel supply pipe, 11... Partition wall. Agent Patent Attorney Takeshi Kawakita 2: Solid electrolyte 3: Oxygen side electrode 4: Fuel side electrode 5a to 5d: Single cell 6: Flange plate 7: Air supply pipe 8: Air pipe 9: Fuel supply pipe 10: Fuel diagonal pipe 1: Partition wall 12: Fuel hole ζ /

Claims (1)

[Claims] (1) A solid electrolyte in which a large number of single cells are arranged on a substrate, in which an oxygen electrode made of an electron conductor, an oxygen ion conductive solid electrolyte, and a fuel electrode made of an electron conductor are stacked on a gas-permeable base tube. type fuel cell, characterized in that the base tube has a cylindrical shape with one end closed, the diameter and height of the base tube are changed stepwise to constitute a single cell, and a large number of these single cells are arranged concentrically. Solid electrolyte fuel cell.