JPH034451A - Gas supply mechanism of solid electrolyte type fuel cell - Google Patents

Abstract

PURPOSE:To draw out power generation capacity up to a high level by providing a plurality of blowoff ports at positions different in the axial direction of an oxygen electrode or a fuel electrode, and providing the gas supply pipe in close vicinity to the oxygen electrode or the fuel electrode. CONSTITUTION:A solid electrolyte type fuel cell 11 is supplied with hydrogen gas by the fuel gas supply pipe 12 inserted in inner space, and when the air is supplied as oxidizing gas to the outside, it causes oxidizing and reducing reactions through solid electrolyte between an inside fuel cell and an outside oxygen electrode, and accompanying these reactions the power is generated. At this time, since plural gas blowoff ports 13 are severally formed at the positions different in axial direction of the fuel gas supply pipe 12, the fuel gas blown off from each gas blowoff port 13 is supplied directly to the inner periphery of the fuel electrode being provided inside the solid electrolyte type fuel cell 11, and enough concentration of fuel gas is supplied uniformly to each part of the fuel electrode. Hereby, the solid electrolyte type fuel cell 11 can be display a high level of power generating capacity.

Description

[Detailed Description of the Invention] Industrial Field of Application This invention is applicable to fuel electrodes of solid electrolyte fuel cells! ! The present invention relates to a gas supply structure for supplying fuel gas or oxidizing gas to at least one side of a primary electric generator.

Conventional technology In a solid oxide fuel cell, a fuel electrode is formed on one side of a solid electrolyte, and an oxygen electrode is formed on the other side, and a fuel gas such as hydrogen is supplied to the fuel electrode side. In addition, by supplying an oxidizing gas containing oxygen such as air to the oxygen electrode side, an oxidation/reduction reaction is caused via a solid electrolyte, and the electric power generated during the reaction is extracted and used.

For example, FIG. 6 shows a conventional general solid oxide fuel cell, in which a housing 1 surrounded by a heat insulating material 1a is divided into a combustion chamber 2 and an exhaust gas chamber 3 by a partition wall 1b. A plurality of bottomed cylindrical single cells 4 are housed in the combustion chamber 2 .

Each of these unit cells 4 has a fuel electrode formed inside a cylindrical solid electrolyte and an oxygen electrode formed outside thereof, and the open base end (upper end in FIG. 6) is connected to a circular shape formed in the partition wall 1b. are airtightly attached to each through hole 1C and arranged parallel to each other.

Air, which is an oxidizing gas, is taken into the combustion chamber 2 from the air intake port 5, flows around the space around the oxygen electrode of each unit cell 4, which has a cylindrical shape with a bottom, and flows around the oxygen electrode of each unit cell 4. A fuel gas such as hydrogen is supplied to the space inside the fuel electrode 4 from the exhaust gas chamber 3 side separated by the partition wall 1b by a fuel gas supply pipe 6 inserted inside through each through hole 1C, Fuel gas blows out from the tip of each fuel gas supply pipe 6 inserted to the inside of each cell 4 to near the bottom of the tip, and flows inside each cell 4 toward the base end side (upward in FIG. 6). After the residual gas flows into the exhaust gas chamber 3 through each through hole 1C, it is discharged from the fuel gas exhaust pipe 7 to the outside of the housing 1. The structure is such that they are electrically connected in parallel and the generated power is extracted.

Problems to be Solved by the Invention However, as in the case of the conventional solid oxide fuel cell described above, it is difficult to insert the fuel gas supply pipe 6 into the inner space where the fuel electrode of each bottomed cylindrical unit cell 4 is formed. In the case of a structure in which the fuel gas is inserted into each cell and fuel gas is ejected from the tip thereof, there is a high height at the tip side of each unit cell 4 where the tip part which is the blowout hole of the fuel gas supply pipe 6 is disposed. However, since the supplied fuel gas is not consumed in the oxidation/reduction reaction and flows toward the proximal end, the concentration of the fuel gas increases as it approaches the proximal end of each cell 4. There was a problem in that the concentration of the fuel gas became dilute on the proximal end side, weakening the oxidation/reduction reaction, and reducing the output of each cell 4.

Therefore, in the past, the amount of fuel gas supplied was increased more than necessary so that fuel gas with a sufficient gas concentration was supplied to positions far from the fuel gas outlet of each cell 4. A drop in output was prevented by supplying fuel gas in an amount that significantly exceeded that required for the oxidation/reduction reactions, but this resulted in the problem of unnecessarily consuming fuel gas due to a large amount of residual gas being hung up. there were.

This invention was made in view of the above circumstances, and it is possible to supply a sufficiently high and equal concentration of fuel gas or an oxidizing gas of sufficient Φ over the entire length of a solid oxide fuel cell. The purpose is to provide a gas supply structure for electrolyte fuel cells.

Means for Solving the Problems As a means for solving the above problems, the gas supply structure of the solid oxide fuel cell of the present invention includes an oxygen electrode or a fuel electrode on the inside of the annular solid electrolyte, and an opposite electrode on the outside. In the cylindrical solid oxide fuel cell provided, gas supply pipes having blow-off holes at a plurality of different positions in the axial direction of the oxygen electrode or the fuel electrode are provided in the vicinity of the oxygen electrode or the fuel electrode. is set as vfyl.

Further, in the present invention, the gas supply pipe can be formed of a single pipe body in which a plurality of blow-off holes are formed.

Further, in the present invention, the gas supply pipe can be constructed of a plurality of pipe bodies having different lengths, each having an open end as a blow-off hole.

Further, in the present invention, each blowing hole of the gas supply pipe can be formed so as to blow gas toward each electrode surface of the oxygen electrode or the fuel electrode.

The oxidizing gas or fuel gas is discharged from the outlet, and the outlet is provided in multiple stages at different positions in the axial direction of the oxygen electrode or fuel electrode, and the gas supply pipe is connected to the oxygen electrode or fuel electrode. Since they are placed close to each other, unreacted, highly concentrated gas is supplied to multiple locations along the axis of the oxygen electrode or fuel electrode, increasing the power generation capacity of each solid oxide fuel cell to a high level. Can be withdrawn.

Embodiments Hereinafter, embodiments of a gas supply structure for a solid oxide fuel cell according to the present invention will be described with reference to FIGS. 1 to 5.

1 and 2 show a first embodiment of a gas supply structure for a solid oxide fuel cell according to the present invention. A solid oxide fuel cell 11 includes a fuel electrode inside an annular solid electrolyte, The solid electrolyte is made of yttria stabilized zirconia (YSZ), the fuel electrode is made of a cermet of nickel and zirconia, and the oxygen electrode is made of velorskite. Each type is formed from a lanthanum-based composite oxide.

In the space inside the fuel electrode of this solid oxide fuel cell 11, a fuel gas supply pipe 12 is inserted approximately at the center of the solid oxide fuel cell 11 in the axial direction. As shown in FIG. 2, this fuel gas supply pipe 12 has a plurality of gas blowing holes 13 formed at different positions in the axial direction in a cylindrical portion disposed in a space inside the fuel electrode.
The tip (the left end in FIG. 1) is inserted into the bottomed cylindrical solid-state lightning-resolved fuel V4 battery 11 up to the vicinity of the bottom of the tip. Further, the solid electrolyte type twisted 'n battery 11 is constructed so that air, which is an oxidizing gas, flows around the outer periphery of the oxygen electrode on the outside.

Next, the operation of this embodiment configured as described above will be explained.

The solid oxide fuel cell 11 is supplied with hydrogen gas through a fuel gas supply pipe 12 inserted into the inner space, and when air is supplied as an oxidizing gas to the outside, the inner fuel electrode and the outer oxygen Oxidation and reduction reactions occur between the electrode and the solid electrolyte, and electric power is generated along with this reaction.

At this time, hydrogen as fuel gas is supplied to the inside of the solid oxide fuel cell 11 through the fuel gas supply pipe 12;
A plurality of gas blowing holes 13 are provided in this fuel gas supply pipe 12.
Since they are formed at different positions in the axial direction, the fuel gas blown out from each gas blowout hole 13 is directly supplied to the inner circumferential surface of the fuel electrode provided inside the solid oxide fuel cell 11, and the fuel gas is Fuel gas of sufficient concentration is evenly supplied to each part of the electrode. As a result, the solid oxide fuel cell 11 can exhibit a high level of power generation performance.

FIG. 3 shows a second embodiment of the gas supply structure for a solid oxide fuel cell according to the present invention.
As in the case of the first embodiment, the J4 battery 21 is formed into a bottomed cylindrical shape with a fuel electrode provided inside a ring-shaped solid electrolyte and a W1 element electrode provided outside. A fuel gas supply pipe 22 is inserted almost into the center of the space inside the fuel electrode of the fuel cell 21, and its open end (the left end in FIG. 3) is connected to a bottomed cylindrical solid oxide fuel cell. The fuel gas supply pipe 22 is inserted into the vicinity of the front yMg portion in the fuel gas supply pipe 21, and hydrogen is supplied through this fuel gas supply pipe 22.

In addition, in the space outside the solid oxide fuel cell 21,
A plurality of oxidizing gas supply pipes 23 each serve as a solid electrolyte.
Each oxidizing gas supply pipe 23 is arranged in parallel with the i-type fuel cell 21, and each oxidizing gas supply pipe 23 has a plurality of gas blowouts in a section corresponding to the outer peripheral part where the M element electrode of the solid oxide fuel cell 21 is formed. The holes 24 are formed at different positions in the axial direction on the side facing the oxygen layer 4j (the outer circumference of the solid oxide fuel cell 21), and oxygen is supplied through the oxidizing gas supply pipe 23. It becomes 0.

Next, the operation of this embodiment configured as described above will be explained.

The solid oxide fuel cell 21 is supplied with hydrogen through a fuel gas supply pipe 22 inserted into the inner air space e1, and oxygen is supplied with oxidizing gas through a plurality of oxidizing gas supply pipes 23 arranged on the outside. When supplied as a gas, oxidation occurs between the inner fuel electrode and the outer oxygen electrode via a solid electrolyte.
A reduction reaction occurs, and electricity is generated along with the reaction.

At this time, oxygen gas is supplied as an oxidizing gas to the outside of the solid oxide fuel cell 21 through each oxidizing gas supply pipe 23 , and each oxidizing gas supply pipe 23 has a plurality of gas blowing holes 24 . are formed at different positions in the axial direction, so that the oxygen gas blown out from each gas blowing hole 24 is directly supplied to the outer peripheral surface of the oxygen electrode provided on the outside of the solid oxide fuel cell 21. Sufficient 1 degree oxygen gas is evenly supplied to each part of the oxygen electrode. As a result, the solid oxide fuel cell 21 can exhibit a high level of power generation performance.

Furthermore, FIG. 4 shows a gas supply pipe used in the gas supply structure of a solid oxide fuel cell according to a third embodiment of the present invention. .33, 34, and the tips of these tubes 32, 33, 34, which serve as gas blowing holes, are arranged at different positions in the axial direction of the solid oxide fuel cell (not shown). It is located in

Therefore, if the gas supply pipe 31 consisting of a plurality of pipe bodies 32, 33, 34 is used as a fuel gas supply pipe or an oxidizing gas supply pipe, or as both a fuel gas supply pipe and an oxidizing gas supply pipe, it is possible to As in the case of the embodiment, W1 element or gas such as hydrogen can be directly supplied to the oxygen electrode or fuel electrode of the solid oxide fuel cell, respectively.
As in both of the above embodiments, the solid oxide fuel cell can exhibit a high level of power generation performance.

FIG. 5 shows a fourth embodiment of the gas supply structure for a solid oxide fuel cell according to the present invention, in which a plurality of individual fuel cells are connected in series in the axial direction around the outer periphery of a porous support tube. This example shows an example in which the present invention is applied to a gas supply structure of a so-called solid oxide fuel cell stack, and will be explained below based on the drawings.

The solid electrolyte fuel cell stack 41 includes a single fuel cell 43 in which a fuel n electrode layer, a solid electrolyte layer, and an oxygen electrode layer are stacked in this order from the inside on the outer periphery of one long support tube 42 . A plurality of fuel cells 43.43 are formed with a predetermined length in the axial direction with a predetermined gap between adjacent fuel cell units 43.43, and each fuel cell unit 43.43 adjacent in the axial direction
An interconnector (not shown) is provided in the gap between them, that is, in the non-battery part 44, so that they are connected in series.

A fuel gas supply pipe 45 is inserted centrally into the space inside the support pipe 42 of the solid oxide fuel cell stack 41.

This fuel gas supply pipe 45 has a nozzle-shaped gas blowing part 46 at a position corresponding to the inner peripheral side (fuel electrode layer side) of each fuel cell unit 43 formed on the outer periphery of the porous support pipe 42. A plurality of each are provided, and each gas blowing part 46
are formed toward the inner peripheral surface of each corresponding fuel cell unit 43. Although not shown, air, which is an oxidizing gas, is supplied to the outer periphery of the solid oxide fuel cell stack 41.

Next, the operation of this embodiment configured as described above will be explained.

The solid oxide fuel cell stack 41 is supplied with hydrogen as a fuel gas through a fuel gas supply pipe 45 inserted into the inner space, and when air is supplied as an oxidizing gas to the outside, the outer periphery of the support pipe 42 In each fuel cell unit 43 formed in plurality, solid electrolysis occurs between the innermost fuel electrode layer and the outermost oxygen electrode layer. Oxidation and reduction reactions occur through the layers, and electric power is generated for each fuel cell unit 43 connected in series.

At this time, hydrogen gas as a fuel gas is supplied to the inside of the solid oxide fuel cell stack 41 through a fuel gas supply pipe 45. Since a plurality of nozzle-shaped gas blowing portions 46 are formed at each position of each fuel cell unit 43 formed, fuel gas is blown out toward the portion of each fuel cell unit 43 between the non-cell parts, Fuel gas is directly supplied to the inside of the innermost fuel electrode layer of each fuel cell unit 43, and a sufficient concentration of fuel gas is evenly supplied to each part of the fuel electrode without waste.

As a result, each fuel cell unit 43 exhibits a high level of power generation performance, and the solid oxide fuel cell stack 41 as a whole can obtain high output.

In addition, in each of the above embodiments, each gas supply pipe 12.2
3, 31, and 45, the gas supply pipes have been described as having straight lines, but the gas supply pipes may have other shapes such as a coil shape.

Detailed Description of the Invention As described above, the gas supply structure of the solid oxide fuel cell of the present invention consists of a cylindrical solid electrolyte with a #1 element electrode or fuel electrode provided inside the annular solid electrolyte and an opposite electrode provided outside. In the electrolyte fuel cell, gas supply pipes with blow-off holes at different positions in the axial direction of the oxygen electrode or the fuel electrode are provided close to the i1 element electrode or the fuel electrode, so that the gas Since fuel gas or oxidizing gas can be directly supplied to each part of the solid oxide fuel cell from each outlet of the supply pipe, sufficient amount of fuel gas or oxidizing gas can be supplied to each electrode, and solid oxide fuel In addition to improving the power generation capacity of the battery, the amount of wasteful fuel gas or oxidizing gas discharged without being used in the reaction can be reduced by 1, thereby greatly improving the utilization efficiency of fuel gas or oxidizing gas. It has effects such as being able to.

[Brief explanation of the drawing]

1 and 2 show a first embodiment of the present invention, in which FIG. 1 is a schematic sectional view showing a gas supply structure of a solid oxide fuel cell, and FIG. 2 is a perspective view of a fuel gas supply pipe. , 3rd
The figure is a schematic sectional view showing the gas supply structure of a solid oxide fuel cell according to the second embodiment of the present invention, and FIG.
A perspective view of a gas supply pipe used in a gas supply structure of a solid oxide fuel cell according to an embodiment, and FIG. 5 is a schematic sectional view showing a gas supply structure of a solid oxide fuel cell stack according to a fourth embodiment of the present invention. , FIG. 6 is a diagram showing an example of a conventional gas supply structure of a fuel cell. DESCRIPTION OF SYMBOLS 11... Solid oxide fuel cell, 12... Fuel gas supply pipe, 13... Gas blow-off hole, 21... Solid oxide fuel cell, 22... Fuel gas supply pipe, 2
3... Oxidizing gas supply pipe, 24... Gas blow-off hole, 31... Gas supply pipe, 32.33.34... Pipe body, 41... Solid oxide fuel cell stack, 42
...Support tube, 43...Fuel cell unit, 44...
・Non-battery part, 45...Fuel gas supply pipe, 46...
・Gas blowing part. Fig. 1 Fig. 4 Fig. 31: Forces, 4 disputes and control Fig. 2 Fig. 6 Fig. 3 ↑ 9

Claims (3)

[Claims] (1) In a cylindrical solid electrolyte fuel cell in which an oxygen electrode or a fuel electrode is provided inside an annular solid electrolyte and an opposite electrode is provided on the outside, a plurality of different positions in the axial direction of the oxygen electrode or fuel electrode are provided. 1. A gas supply structure for a solid oxide fuel cell, characterized in that a gas supply pipe with a blowout hole is provided in close proximity to an oxygen electrode or a fuel electrode. (2) The gas supply structure for a solid oxide fuel cell according to claim 1, wherein the gas supply pipe is a single pipe body in which a plurality of blow-off holes are formed. (3) The gas supply structure for a solid oxide fuel cell according to claim 1, wherein the gas supply pipe is composed of a plurality of pipe bodies of different lengths each having an open end as a blowout hole. . (4) Claim 1, wherein each blowout hole of the gas supply pipe is formed so as to blow out gas toward each electrode surface of the oxygen electrode or the fuel electrode.
4. A gas supply structure for a solid oxide fuel cell according to any one of 3 to 3.