JP3151916B2 - Solid oxide fuel cell - Google Patents

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.

[0002]

2. Description of the Related Art For example, a plate type fuel cell is known as one type of solid oxide fuel cell. In this type of fuel cell, a solid electrolyte having a fuel electrode and an air electrode provided on the front and back surfaces, a fuel gas and air (oxygen) are uniformly supplied to the fuel electrode and the air electrode, and a path for electric charges generated at the electrodes is provided. It has a laminated structure composed of a conductive distributor and an interconnector.

[0003] Distributors are required not only to have excellent conductivity but also to have sufficient bonding strength with a solid electrolyte. However, since the conventional anode-side distributor uses nickel-zirconia cermet of the same composition as the anode, the anode-side distributor and the solid electrolyte peel off due to the temperature rise and fall during operation, and the fuel cell body is damaged. There was a problem of doing.
This is because the thermal expansion coefficient of nickel-zirconia cermet is larger than the thermal expansion coefficient of zirconia, which is a material of a main component (for example, a solid electrolyte) of a fuel cell.

Accordingly, an object of the present invention is to provide a solid electrolyte provided with a fuel electrode side conductive distributor which does not cause separation between the solid electrolyte and the fuel cell body when the temperature rises and falls during operation. To provide a fuel cell.

[0005]

In order to solve the above-mentioned problems, a solid oxide fuel cell according to the present invention comprises:
(A) a solid electrolyte provided with a fuel electrode and an air electrode on the front and back surfaces, and (b) a fuel electrode-side conductive distributor made of nickel, zirconia, and zircon provided on the fuel electrode side of the solid electrolyte; c) a cathode-side conductive distributor disposed on the cathode side of the solid electrolyte;
(D) an interconnector joined to at least one of the fuel electrode side or the air electrode side conductive distributor;
It is characterized by having.

In the above configuration, the anode-side conductive distributor is made of nickel, zirconia, and zircon. Therefore, the thermal expansion coefficient of the anode-side conductive distributor is a main component of the fuel cell (for example, a solid electrolyte).
Has a thermal expansion coefficient substantially equal to that of zirconia, which is a material of
Therefore, when the temperature rises and falls during operation, no separation occurs between the fuel electrode side distributor and the solid electrolyte, and the fuel cell body is not damaged.

[0007] The conductivity of the fuel electrode side distributor is determined by the nickel content, and the nickel content is set within a range that does not cause practical problems. Then, the contents of zirconia and zircon are set according to the nickel content.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a solid oxide fuel cell according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an exploded perspective view of a solid oxide fuel cell. The solid electrolyte 1 has a rectangular shape, and is made of yttrium-stabilized zirconia or the like. The air electrode 2 and the fuel electrode 3 are provided on the upper surface and the lower surface of the solid electrolyte 1, respectively.
Nickel-zirconia cermet or the like is used as a material of the fuel electrode 3, and lanthanum manganite or the like is used as a material of the air electrode 2.

The air electrode side conductive distributor 5 and the fuel electrode side conductive distributor 6 are provided on the surface of the air electrode 2 and the fuel electrode 3 so that the fuel gas and the air are evenly distributed to the air electrode 2 and the fuel electrode 3. In addition to functioning, the electrodes 2 and 3 function so as to be electrically connected to an interconnector 10 described later. As shown in Table 1, the material of the fuel electrode side distributor 6 is such that the weight ratio of nickel is 45 wt% and the weight ratio of zirconia and zircon is changed (see LOT Nos. 1 to 6). As a material of the air electrode side distributor 5, lanthanum manganite or the like is used.

The spacers 7 and 8 are arranged on both sides of the aligned distributors 5 and 6, respectively, and block air and fuel gas from outside air. As a material for the spacers 7 and 8, yttrium-stabilized zirconia or the like is used. As described above, the solid electrolyte 1 having the air electrode 2 and the fuel electrode 3 provided on the surface, the distributors 5 and 6, the spacers 7,
And an interconnector 1 above and below a unit cell 9 composed of
0 is provided. Lantern chromite or the like is used as a material of the interconnector 10.

FIG. 2 is a perspective view showing a solid oxide fuel cell 20 in which five single cells 9 are stacked via an interconnector 10. After the fuel cell 20 thus obtained is repeatedly raised and lowered a predetermined number of times from room temperature to 1000 ° C., the fuel electrode side distributor 6 and the solid electrolyte 1
Table 1 shows the results of the evaluation of the bonding state and the damaged state of the fuel cell 20.

[0012]

[Table 1]

In Table 1, the weight ratio of zircon is 1
It is shown that in the range of 0 to 35 wt%, the bonding strength between the fuel electrode side distributor 6 and the solid electrolyte 1 is sufficient, and the fuel cell 20 main body is not damaged.
The solid oxide fuel cell according to the present invention is not limited to the above embodiment, but can be variously modified within the scope of the gist. In particular, the weight ratio of nickel is 45
It is not limited to wt%, but can be changed within a range that does not impair the conductivity of the fuel electrode side distributor. Then, the weight ratio of zirconia and zircon is set according to the weight ratio of nickel.

[0014]

As is apparent from the above description, according to the present invention, the anode-side conductive distributor is made of nickel, zirconia, and zircon. It has a thermal expansion coefficient substantially equal to that of zirconia which is a material of a main component of the battery. As a result, a solid oxide fuel cell having a fuel electrode side conductive distributor that does not cause separation between the solid electrolyte and the fuel cell body when the temperature rises and falls during operation and does not damage the fuel cell body is obtained.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a single cell and an interconnector constituting an embodiment of a solid oxide fuel cell according to the present invention.

FIG. 2 is a perspective view showing the appearance of one embodiment of the solid oxide fuel cell according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Solid electrolyte 2 ... Air electrode 3 ... Fuel electrode 5 ... Air electrode side conductive distributor 6 ... Fuel electrode side conductive distributor 10 ... Interconnector 20 ... Solid electrolyte type fuel cell

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-207456 (JP, A) JP-A-5-151982 (JP, A) JP-A-5-174844 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H01M 8/00-8/24

Claims (1)

(57) [Claims] 1. A solid electrolyte provided with a fuel electrode and an air electrode on the front and back surfaces, a fuel electrode-side conductive distributor made of nickel, zirconia and zircon provided on the fuel electrode side of the solid electrolyte; A solid electrolyte type, comprising: an air electrode side conductive distributor disposed on the air electrode side of the electrolyte; and an interconnector joined to at least one of the fuel electrode side or the air electrode side conductive distributor. Fuel cell.