JP2777725B2 - Solid electrolyte type cylindrical fuel cell unit and its manufacturing method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell using a solid electrolyte, in particular, one electrode made of a porous material is formed in a cylindrical shape, and the outer periphery thereof is made of a solid electrolyte and a porous material. The present invention relates to a single fuel cell (single cell) which is formed by sequentially forming the other electrode and arranged on the outer periphery of the current collector, and one of the electrodes is electrically connected to the current collector by an interconnector, and a method of manufacturing the single fuel cell. Things.

2. Description of the Related Art The principle configuration of this type of battery is that an oxidizing agent such as air and a reducing agent such as hydrogen gas are arranged between a solid electrolyte having ion conductivity, and the oxidizing agent and the reducing agent are respectively used. An electrode is used to obtain electric power in association with an oxidation-reduction reaction via an electrolyte. Since the power of only one cell having such a configuration is small, in practice, a plurality of cells are connected by an interconnector to form a stack, and a plurality of the stacks are required to be connected. Voltage and current are obtained. FIG. 3 is a simplified illustration of an example of the related art, and the fuel cell shown here is one in which six cells are arranged in one stack and 20 stacks are connected in series and parallel. That is, five stacks 3 are arranged between each of the five electrode plates 2 having the insulating film 1 formed on one surface, and one of the Ni tubes 4 forming the jacket of each stack 3 is ( Conduction is made only to the lower electrode plate 2 in FIG. As shown in an enlarged cross-sectional view in FIG. 4, each stack 3 has a central portion of a Ni tube 4 whose inner peripheral surface is covered with Ni felt 5, and a central portion of which has an outer peripheral surface of Ni tube 6 covered with Ni1 felt 7. Electrons 8 are arranged concentrically, and six unit cells (cells) 9 are arranged between these Ni felts 5 and 7. Then, as shown in FIG. 5 as an enlarged sectional view, the cell 9 has α
A cathode 11 made of LaCoO ₃ or La _1-x Sr _x MnO ₃ is formed on the outer periphery of a porous support tube 10 made of alumina (α-Al ₂ O ₃ ), CaO, ZrO ₂ or the like, and the outer periphery thereof is formed; The solid electrolyte 12 is formed, and an interconnector 13 penetrating a part of the solid electrolyte 12 in the radial direction and conducting to the cathode 11 is further provided, and an anode made of Ni or the like so as not to hide the interconnector 13 on the outer periphery of the solid electrolyte 12 is provided. The cells 9 having such a configuration are equally arranged on the outer periphery of the current collector 8 with the interconnector 13 electrically connected to the current collector 8. Each current collector 8 is electrically conducted by a predetermined means (not shown) to an electrode plate (the upper electrode plate in FIG. 3) 2 insulated by the insulating film 1 with respect to the Ni tube 4 forming the jacket. Therefore, for example, by flowing air through the inside of each cell 9 and flowing hydrogen gas around the anode 14, the oxidation / reduction reaction via the solid electrolyte 12 causes the upper electrode plate in FIG. 2 serves as an anode, and the lower electrode plate 2 serves as a cathode.

By the way, since the above-mentioned cell 9 has a cylindrical multilayer structure mainly made of ceramic, it has been conventionally manufactured as follows. That is, first, a cylindrical support tube 10 having a ridge on the outer surface for mounting the interconnector 13 is manufactured, and the cathode 11 is formed on the outer surface of the support tube 10 by spraying or slurry coating with the ridge portion masked. Then, the solid electrolyte 12 is formed on the outer periphery by thermal spraying, the anode 14 is formed on the outer periphery by thermal spraying, and thereafter, the interconnector 13 is formed by thermal spraying on the tip end surface of the ridge.

Problems to be Solved by the Invention However, in the conventional cell described above, the porous support tube 10 is composed of a ceramic material that emphasizes strength such as α-alumina, and LaCoO ₃ and La _1-x SrMnO ₃ are provided on the outer periphery thereof. Since the cathode 11 made of is formed, the support tube 10 or the cathode 11 may be broken due to a difference in thermal expansion coefficient between the two. Air flowing through the center of the support tube 10 passes through the inside of the support tube 10 and the cathode 11 to form a solid electrolyte.
Therefore, there is a problem that the support pipe 10 affects the diffusion of air because the inner surface of the support pipe 12 is reached.

In addition, as for the manufacturing method, the support tube 10 is first manufactured, and the cathode 11 is formed on the outer periphery thereof by a method such as thermal spraying or slurry coating. In forming the anode 14, the portion where the interconnector 13 is to be formed is masked, and the solid electrolyte 12 and the anode material are sprayed in that state. Work has to be difficult, and in this respect the work time is long,
In addition, there is a problem that the cost is increased.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and provides a solid electrolyte cylindrical fuel cell unit which has no risk of cracking due to a temperature change and has good manufacturing workability, and a method of manufacturing the fuel cell unit. The purpose is to do so.

Means for Solving the Problems In order to achieve the above object, the fuel cell unit of the present invention has a cylindrical body having an air passage in the center and a ridge extending substantially along the axial direction on the outer surface. A solid electrolyte is formed on a portion of the outer periphery of the cylindrical body except for the front end surface of the ridge, and the front end surface of the ridge not covered with the solid electrolyte is formed of a porous ceramic material. An interconnector is attached, and a fuel electrode material is provided on the outer surface of the solid electrolyte.

Further, in the fuel cell unit of the present invention, the conductive porous ceramic material can be a perovskite-type lanthanum-based composite oxide represented by the following formula.

^{_{La 1-x M * x M}} ** O 3 where, 0 ≦ x ≦ 1 mole M * is an alkaline earth metal M ^** is Mn or a transition metal other hand, the production method of the present invention, the center hollow Toshikatsu A cylindrical body having a ridge extending substantially along the axial direction on the outer surface is formed of a conductive porous ceramic material, and a solid electrolyte is applied to an outer peripheral surface of the cylindrical body. Then, a fuel electrode is formed on the surface of the solid electrolyte. The method is characterized in that a material is applied, and thereafter, the solid electrolyte and the fuel electrode material on the tip surface of the ridge are removed, and an interconnector is formed in the removed portion.

In this manufacturing method, a perovskite-type lanthanum-based composite oxide represented by the following formula can be used as the conductive porous ceramic material.

^{_{La 1-x M * x M}} ** O 3 except that the 0 ≦ x ≦ 1 mole M ^* is in the process of alkaline earth metals M ^** is Mn or a transition metal or the present invention, the solid electrolyte and fuel electrode material It can be applied by thermal spraying or vapor deposition.

In the fuel cell unit according to the present invention, air as an oxidant flows through an air passage at the center of a cylindrical body formed of the conductive ceramic material, and a fuel such as hydrogen gas flows outside the outermost fuel electrode material. By flowing the gas, oxygen in the air reacts with the fuel gas through the solid electrolyte to generate electric power. In this case, the tubular body serves as an air electrode, and at the same time, the tubular body serves as a strength member for supporting the whole. Then, a plurality of the interconnectors are used integrally with each other in a state where the interconnector is connected to an appropriate current collector.

Embodiments Next, the present invention will be described in detail based on embodiments.

First, the fuel cell unit of the present invention will be described. FIG. 1 is a schematic cross-sectional perspective view showing an example of the fuel cell. An air passage 20 is formed along a central axis of a cylindrical body 21. the shape of shaped body 21 has a shape to form a ridge 22 along the substantially axial direction on a part of the outer surface of the cylindrical body and its cylindrical body ^{_{21, La 1-x M * x}} M ** O ₃ (However, 0 ≦ x ≦ 1
mole, M ^* is alkaline earth metal, M ^** is Mn or transition metal) Perovskite-type lanthanum-based composite oxide (eg, La _1-x Sr _x MO ₃ ) and a porous structure made of a conductive ceramic material It is formed as. The solid electrolyte 23 is applied to a portion of the outer surface of the cylindrical body 21 other than the end face of the ridge. As the solid electrolyte 23, a ion-conductive _{(Y 2 O 3) x ·} (ZrO 2) 1-x ( where, x is 0.08～0.1Mole) may be a known ceramic material such as.

Further, a fuel electrode material 24 made of Ni, Ni-cermet composite, or the like is adhered to the outer peripheral surface of the solid electrolyte 23.

An interconnector 25 made of LaCrO ₃ , Ni, or the like is formed on the tip end surface of the ridge 22, and the tubular body 21 is electrically connected to the outside by the interconnector 25, and the outer periphery of the tubular body 21 is airtight. Is secured.

In the same manner as the conventional fuel cell, a plurality of the above fuel cells are equally arranged on the outer periphery of the current collector, and each of the interconnectors 25 is connected to the current collector. An oxidant is supplied, and a fuel gas such as hydrogen gas is supplied to the outer peripheral surface. As a result, the oxidant reacts with the fuel gas via the solid electrolyte 23 to generate electric power, and accordingly, the tubular body 21 becomes an anode, and the fuel electrode material 24 becomes a cathode.

Therefore, the single fuel cell described above serves as a support member for supporting the entire body at the same time as the cylindrical body 21 serving as an anode.

Next, a method for manufacturing the above-described fuel cell alone will be described. First, as shown in FIG. 2 (A), a cylindrical shape having a through hole serving as an air passage 20 in the center and a convex ridge 22 on the outer surface. Build body 21. This is, for example, extruding a ceramic material kneaded with a resin into a predetermined shape by extrusion molding,
The molded body can be manufactured through the steps of degreasing and sintering. Next, as shown in FIG. 2 (B), a solid electrolyte 23 is applied to the entire outer peripheral surface of the tubular body 21. Further, as shown in FIG. 2 (C), the outer peripheral surface of the solid electrolyte 23 is formed. Then, a fuel electrode material 24 is applied. These solid electrolytes 23
The fuel electrode material 24 can be applied by, for example, thermal spraying or steam. Thereafter, an interconnector 25 is provided, which is performed as follows. That is, the fuel electrode material 24 and the solid electrolyte 23 on the tip surface of the ridge 22 are removed as shown in FIG. 2 (D), and LaCrO ₃ or Ni is sprayed or vapor-deposited on the removed portion to form an interconnector 25. Is formed as shown in FIG. 2 (E).

That is, in the above-described method, the masking is not particularly performed, and even if the masking is performed, only the portion other than the ridge 22 is masked when the interconnector 25 is formed. As a result, the workability is good. .

Effect of the Invention As described above, in the fuel cell unit of the present invention, La
_{^{1-x M * x M **}} O 3 ( where, 0 ≦ x ≦ 1 mole, M * is an alkaline earth metal, M ^** is Mn or a transition metal) such as perovskite lanthanum composite oxide represented by Since the cylindrical body formed of the conductive ceramic composite oxide also serves as the cathode and the support member, there is no risk of cracking due to a difference in thermal expansion coefficient when two types of ceramic materials are joined, and the cathode side In this case, there is little influence on gas diffusion, and the step of forming only the cathode can be omitted, so that the manufacturing time can be reduced, and the size and weight can be reduced. In addition, since the dimensional restrictions are relaxed, the electrodes can be made thicker, the internal resistance can be reduced accordingly, and a single fuel cell having good electrical characteristics can be obtained.

On the other hand, according to the manufacturing method of the present invention, since the masking of the interconnector portion having a small size is not required, the worker becomes good, and as a result, the fuel cell unit can be manufactured in a short time and at low cost. .

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional perspective view showing an embodiment of the present invention, and FIGS. 2 (A), 2 (B), 2 (C), 2 (D), and 2 (E) are cross-sectional views showing a manufacturing process by the method of the present invention. FIG. 3, FIG. 3 is a sectional view showing an example of a fuel cell constituted by connecting a plurality of cells in series and parallel, FIG. 4 is a sectional view showing one of the stacks, and FIG. 5 shows a conventional cell. It is sectional drawing. 20 ... air passage, 21 ... cylindrical body, 22 ... ridge, 23 ... solid electrolyte, 24 ... fuel electrode material, 25 ... interconnector.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Shoichi Hasegawa 1-5-1 Kiba, Koto-ku, Tokyo Inside Fujikura Electric Wire Co., Ltd. (72) Inventor Hiroshi Yamanouchi 1-1-5-1 Kiba, Koto-ku, Tokyo Fujikura (72) Inventor Masakatsu Nagata 1-5-1, Kiba, Koto-ku, Tokyo Fujikura Electric Wire Co., Ltd. (56) References JP-A-63-86360 (JP, A) (58) Fields investigated ( Int.Cl. ⁶ , DB name) H01M 8/00-8/02 H01M 8/08-8/24

Claims (5)

(57) [Claims] 1. A cylindrical body having an air passage in a center portion and a convex ridge extending substantially along an axial direction on an outer surface is formed of a conductive porous ceramic material. The solid electrolyte is applied to the portion excluding the end surface of the solid electrolyte, an interconnector is attached to the end surface of the ridge that does not have the solid electrolyte, and a fuel electrode material is provided on the outer surface of the solid electrolyte. A solid electrolyte type cylindrical fuel cell unit characterized in that: 2. The solid electrolyte type cylindrical fuel cell according to claim 1, wherein the conductive porous ceramic material is a perovskite-type lanthanum-based composite oxide represented by the following formula. ^{_{La 1-x M * x M}} ** O 3 where, 0 ≦ x ≦ 1 mole M * alkaline earth metals M ^** is Mn or a transition metal 3. A cylindrical body having a hollow central part and having a ridge extending substantially in the axial direction on the outer surface is formed of a conductive porous ceramic material, and a solid electrolyte is applied to the outer peripheral surface of the cylindrical body. Then, a fuel electric field material is applied to the surface of the solid electrolyte, and thereafter, the solid electrolyte and the fuel electrode material on the tip surface of the ridge are removed, and an interconnector is formed in the removed portion. Of solid electrolyte type cylindrical fuel cells. 4. The method according to claim 3, wherein the conductive porous ceramic material is a perovskite-type lanthanum-based composite oxide represented by the following formula. . ^{_{La 1-x M * x M}} ** O 3 where, 0 ≦ x ≦ 1 mole M * alkaline earth metals M ^** is Mn or a transition metal 5. The method according to claim 3, wherein the solid electrolyte and the fuel electrode material are applied by thermal spraying or vapor deposition.