JPH06215778A - Solid electrolyte-type fuel cell - Google Patents

Abstract

PURPOSE:To lower the electric resistance, lessen the quantities of oxygen electrodes and a fuel cell, improve electricity generation efficiency, and lower the cost. CONSTITUTION:A hollow part 25 is formed in both sides of an electricity generating layer 21 consisting of a fuel electrode 23, a solid electrolyte 22, and an oxygen electrode 24. The projected part 26a in the outer side of the hollow part 25 in the fuel electrode side and an inter connector layer 28 are electrically joined with a first conductive adhesive 27 and at the same time a projected part 26b in the outer side of a hollow part 25 in the oxygen electrode side of another electricity generating layer 21 and the projected part 26a are set face to face and joined with a second conductive adhesive 29.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid oxide fuel cell (SOFC), and more particularly to an SOFC which can be used not only for power generation but also for electrolytic cells such as water electrolysis and CO ₂ electrolysis.

[0002]

2. Description of the Related Art FIG. 3 is a schematic view of a conventional SOFC (Japanese Patent Application No. 2-48031).

Reference numeral 1 in the drawing denotes a power generation layer, which has a structure in which an oxygen electrode 3 and a fuel electrode 4 are arranged on both sides of a solid electrolyte 2, respectively. Laminated bodies 8a and 8b in which the oxygen electrode layer 6 and the fuel electrode layer 7 are laminated on both sides of the interconnector material 5 are arranged above and below the power generation layer 1. The outer top portion 9 on the upper side of the power generation layer 1 is joined to the upper laminated body 8a, and the fuel passage 10 is formed in the space created thereby. On the other hand, the lower outer top portion 11 of the power generation layer 1 is joined to the lower laminated body 8b, and an oxidant passage 12 is formed in the space created thereby.

As is clear from the invention of the present application, this is because in the field, the members that are not directly involved in power generation, such as a supporting member, are unnecessary in the structure that was considered in the mainstream before that. This is a really important idea.

[0005]

The SOFC has a power generation efficiency of more than 60% and is positioned as an important energy measure, but measures such as manufacturing cost are required. From this point, the prior art of FIG. 3 has an important point, but it requires the oxygen electrode layer 6 and the fuel electrode layer 7 which are not directly involved in the power generation itself.

The reason for this is that since the power generation layer 1 has a dimple structure, the generated electrons are concentrated in the dimple portion (recessed portion), and if they are directly joined to the interconnector material, the electrical resistance increases, so that electrons are generated. This is because each of the dimples is in contact with the electrode material so as to diffuse and allow a lateral flow of electrons.

The present invention has been made in view of the above circumstances, and aims to reduce the electric resistance as much as possible by making the best use of the respective characteristics, and also to provide a solid electrolyte fuel cell in which the number of members is reduced in the structure as a battery. The purpose is to provide.

[0008]

According to the present invention, a recess is provided on both surfaces of a power generation layer composed of three layers of a fuel electrode, a solid electrolyte and an oxygen electrode, and a protrusion on the outer side of the recess on the fuel electrode side has a first structure. 1
The electrical connection is made with the interconnector layer via a conductive adhesive, and the convex portion on the outer side of the concave portion on the oxygen electrode side of the other power generation film facing the convex portion is interposed with the second conductive adhesive. It is a solid oxide fuel cell characterized by being joined together.

[0009]

[Function] SOFC is a ceramic electrolyte YS
Since Z is used, the thermal expansion coefficients of the respective battery constituent members are made equal to prevent cracking due to deformation caused by the fact that the electrolytes are constrained by the difference in thermal expansion.

From this, the coefficient of thermal expansion matched to the electrolyte
Fuel electrodes, oxygen electrodes and interconnector materials of
The electric resistance of the material is neglected to some extent
It As a typical material example in this case, the present inventors
The following was obtained from the experimental results. Interconnector material: LaSrCrO₃(Thickness 1 mm) Hydrogen side: conductivity 1 s / cm, resistance 0.1 Ω · cm²  Oxygen side: conductivity 30s / cm, resistance 0.03Ω · cm²  Average: conductivity 10s / cm, resistance 0.01Ω · cm²  Oxygen electrode material: LaSrMnO₃(Thickness 50 μm) conductivity 20 s / cm, resistance 2.5 × 10^-FourΩ ・ cm²  Fuel electrode material: Ni / YSZ (60:40) (thickness 50 μm) conductivity 500 to 1000 s / cm, resistance 1 × 10^-FiveΩ ・ cm²

Although all the resistances are in the longitudinal flow direction, as is clear from this, the interconnector layer is overwhelmingly electrically conductive, including the fact that the structural member needs to have such a thickness as to have its own strength. Since the resistance is large, it is necessary to make this electrical flow as short as possible.

Further, when applying FIG. 4 which shows these in a schematic electric flow, when the pitch of the dimples is 3 mm, the lateral flow of electrons is 1.5 mm, and at this time, the interconnector is LaSrCrO ₃ and the thickness is 2 mm. When the thicknesses of the fuel electrode (Ni / YSZ) and the oxygen electrode (LaSrCrO ₃ ) are changed, the resistances of these three phases as a whole are shown in "Table 1" below.

[0013]

[Table 1]

As is clear from Table 1, the thickness of the fuel electrode side should be at most 50 μm, but the oxygen electrode side greatly depends on the thickness to reduce the electric resistance. In the present invention, since resistance due to such a lateral flow does not occur, a relatively thin adhesive material (usually the same material as the oxygen electrode is used) is electrically coupled even when connecting the oxygen electrode of the power generation layer and the interconnector. It is understood that it is sufficient to apply as much as possible.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIG.

Reference numeral 21 in the figure denotes a power generation layer, which is a solid electrolyte.
A fuel electrode 23 and an oxygen electrode 24 are respectively formed on the upper and lower surfaces of 22. A large number of dimples (concave portions) 25 are formed on both surfaces of the power generation layer 21, and convex portions 26a and 26b are formed on the opposite side of the dimples 25. The fuel electrode-side convex portion 26a of the power generation layer 21 is connected to an interconnector material 28 via an adhesive 27 that is a common material with the fuel electrode 23. On the other hand, the convex portion 26b on the oxygen electrode side of the power generation layer 21 is connected to the oxygen electrode 23 by an interconnector material 28 via an adhesive 29 which is a common material. Reference numeral 30 in the figure is a region surrounded by the power generation layer 21, the adhesive 27, and the interconnector material 28, that is, a fuel passage for supplying the fuel gas to the fuel electrode 23. Also,
Reference numeral 31 in the figure denotes an area surrounded by the power generation layer 21, the adhesive 29 and the interconnector material 28, that is, an oxidant passage for supplying oxygen to the oxygen electrode 24.

Thus, the SOFC according to this embodiment
Comprises a power generation layer 21 in which a fuel electrode 23 and an oxygen electrode 24 are respectively formed on the upper and lower surfaces of a solid electrolyte 22, and the convex portions 26a on the fuel electrode side of the power generation layer 21 are formed on the fuel electrode side.
23 is connected to the interconnector material 28 through an adhesive 27 which is a common material with the oxygen electrode 23, and the convex portion 26b on the oxygen electrode side of the power generation layer 21 is connected through an adhesive 29 which is a common material with the oxygen electrode 23.
Since 28 is connected, it is possible to suppress the lateral flow of electrons in the interconnector material having a large resistance.

[0018]

As described above in detail, according to the present invention, the electric resistance can be reduced, the oxygen electrodes and the fuel cells can be reduced in amount, and the power generation efficiency can be improved and the cost can be reduced. A fuel cell can be provided.

[Brief description of drawings]

FIG. 1 is an explanatory view of a solid oxide fuel cell according to an embodiment of the present invention.

FIG. 2 is a schematic perspective view of a power generation layer that is one configuration of the solid oxide fuel cell of FIG.

FIG. 3 is an explanatory view of a conventional solid oxide fuel cell.

4 is a schematic diagram showing a flow of electrons in the solid oxide fuel cell of FIG.

[Explanation of symbols]

21 ... Power generation layer, 22 ... Solid electrolyte, 23
… Fuel electrode, 24… Oxygen electrode, 25… Dimples,
26a, 26b ... convex portion, 27, 29 ... adhesive,
30 ... Fuel passage, 31 ... Oxidant passage.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hitoshi Miyamoto 2-1-1, Niihama, Arai-cho, Takasago-shi, Hyogo Prefecture Takasago Laboratory, Mitsubishi Heavy Industries, Ltd. (72) Koichi Takenobu, Wadazaki-cho, Hyogo-ku, Kobe-shi, Hyogo No. 1-1, Mitsubishi Heavy Industries, Ltd. Kobe Shipyard

Claims (1)

[Claims] 1. A dent is provided on both surfaces of a power generation layer composed of three layers of a fuel electrode, a solid electrolyte and an oxygen electrode, and a convex portion outside the dent on the fuel electrode side is provided with a first conductive adhesive agent. In addition to electrically connecting with the interconnector layer, a convex portion outside the concave portion on the oxygen electrode side of another power generation film facing the convex portion is joined via a second conductive adhesive. Solid oxide fuel cell.