JPS63178458A - Cylindrical solid electrolyte fuel cell - Google Patents

Abstract

PURPOSE:To substantially increase the quality of cell group by arranging in the same direction a plurality of substrate pipes each of which is formed by arranging plural unit cells in series, and electrically connecting the substrate pipes with conductive materials in several portions. CONSTITUTION:A plurality of stacks 27 are arranged in a line in the same direction, and unit cells 26 are electrically connected with metal plates 29 in several portions in the lengthy direction of the stacks. The unit cells 26 are connected in parallel, then connected in series. Even if one unit cell is disconnected, current flows through other unit cells 26 connected in parallel. Therefore, the influence of disconnected cell is negligible, and the quality of a cell group is substantially increased. Thereby, the assemblage of a huge number of cells is made possible and a large scale power generating plant can be realized.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a cylindrical solid electrolyte fuel cell (cylindrical 5OFG
>Regarding improvements.

[Prior art] Conventionally, as a cylindrical solid electrolyte fuel cell, as shown in Figs.
The thing shown in the figure is known as JP-A-52-12174.
No. 3).

1 in FIG. 6 is a single battery. This cell 1 is the seventh
As shown in the figure, fuel electrode 2. It is constructed by stacking a solid electrolyte membrane 3, an ink connector 4, and a fuel electrode 5, and has a structure in which a plurality of unit cells 1 having such a structure are arranged in series on a base tube 6 (hereinafter referred to as a stack 7). ). and,
The stack 7 has a structure in which a two-layer liquid m8 of a metal film and an oxide film is coated on the base tube 6, and a current is taken out through a water-cooled metal terminal 9 as shown in FIG. According to the solid electrolyte fuel cell with this structure,
Although the 5OFC1 battery can only obtain an electromotive force of about 0.9V, the stack 7 can obtain an electromotive force of about 0.9V, which is several times the number of batteries. Since it is possible to increase the voltage relatively easily in this way, it is very advantageous from the viewpoint of electricity users.

[Problems to be Solved by the Invention] However, the conventional solid electrolyte fuel cell has the following problems.

■In extreme cases, one of the multiple cells in the stack 7
If the battery becomes electrically disconnected due to damage or manufacturing error,
No current will flow through all of the plurality of cells in the stack 7. In this way, the total performance of the plurality of single cells in the stack 7 is strongly influenced by the performance of the worst battery among the plurality of single cells. In other words, in order to bring out 100% of the battery performance of the stack 7, all the single cells 1 must be in a perfect state. Therefore, a sampling inspection is insufficient for inspection, and a complete inspection is required, resulting in an enormous amount of inspection man-hours. In addition, the stack 7 includes a large number of single cells 1
are connected in series on one base tube, and even if the defective rate of a single cell is small, when considered as a stack 7, the defective rate is multiplied by the number of cells, resulting in poor yield.

(2) A similar problem occurs when a plurality of stacks 7 are connected in series to increase the voltage, so when increasing the size of the device, it is necessary to eliminate the defective rate of single cells. for example,
When building a 1 million kW class power plant, even if the output of each battery is 5W, it is necessary to have one 2g cell in perfect condition, but this is impossible even with current technology. close.

Further, since the structure is such that the current is extracted through the water-cooled metal terminal 9, there are the following problems.

(2) Since the electromotive force per cell of 5OFC is as low as approximately 0.9V, it is important to find out how to obtain a large output even if the resistance of the single cell is made small. One example is the thinning of yttria-stabilized zirconia (YSZ), which is a solid electrolyte. That is, YSZ is the most important component of 5ol-C, allowing only 02'' ions to pass through at high temperatures. However,
Since the specific resistance is several orders of magnitude higher than that of other components, it is a significant factor in increasing the resistance of the battery, but by making the film thinner, this effect has become relatively small.

In addition, we examined the structural materials of oxygen electrodes, fuel electrodes, interconnectors, etc., and in the conventional example, the resistance per cell was reduced to 0.10.
It is set to about 0.

As mentioned above, in the conventional example, the resistance of the battery part is set to 0.
Efforts have been made to lower the current to the order of 0.01 Ω, but the current extraction method uses a double wave [18] structure to conduct electricity from the operating temperature of the 5OFG to the metal terminal 9, which is water-cooled and has a structure close to room temperature. For this reason, 100 of the base tube 6
In consideration of temperature changes from 0° C. to room temperature and thermal stress, a length of several tens of cam units is required. Moreover, the electrical resistance (specific resistance) of metal materials tends to increase as the temperature increases, as shown in FIG. Therefore, the resistance of the current extraction section also increases to an extent that cannot be ignored, and the output at the 5OFG output terminal decreases.

■The metal terminal 9 has a water cooling mechanism 10, and naturally the base tube 6
It will take up more space.

Therefore, the installation pitch of the base tubes 6 cannot be made smaller than the dimensions of the water cooling mechanism 10, and the base tubes 6 cannot be arranged in high density.

■5OFC needs to be operated at a high temperature of approximately 1000℃, and in order to improve the total fuel thermal efficiency including the power generation equipment, there are two ways to a) retain the heat in the high temperature power generation section, that is, transfer it to areas other than the power generation section. It is very important to reduce heat dissipation and b) how to utilize the heat of the hot gas. However, in the conventional case, since both ends of the base tube 6, which also serves as gas supply and exhaust, are fixed to water-cooled metal terminals 9, heat dissipation in this direction is extremely large, and a large amount of energy is required to heat the power generation section. shall be. In addition, the waste gas is also cooled to near room temperature, and reuse of that heat is hardly expected in terms of fuel thermal efficiency.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a cylindrical solid electrolyte fuel cell that dramatically improves the quality of a battery group and has great potential for use in large-scale power generation plants.

[Means and effects for solving the problems] The present invention has a plurality of base tubes in which a plurality of unit cells are arranged in series, one in the same direction.
The gist is to arrange the base tubes in rows and electrically connect the base tubes to each other at a plurality of locations using a conductive material. According to the present invention, there are effects such as dramatically improving reliability as a battery group.

[Example] Hereinafter, an example of the present invention will be described with reference to FIGS. 1 to 3. Here, FIG. 1 is a perspective view of a cylindrical solid electrolyte fuel cell according to an embodiment of the present invention, and FIG.
A cross-sectional view taken along xsia, and FIG. 3 shows an equivalent circuit diagram of the same fuel cell.

21 in the figure is a base tube. This base i! Above 21 is an oxygen electrode 22. Solid electrolyte 1I23. A plurality of unit cells 26 in which interconnectors 24 and fuel electrodes 25 are stacked are arranged in series, thus forming a stack 27. As shown in FIG. 1, a plurality of stacks 27 are arranged in a line in the same direction to form a stack row 28. The unit cells 26 constituting the stack 27 are laterally connected by a metal felt or metal plate 29 made of nickel or the like. However, in the equivalent circuit diagram of Fig. 3, for example, if the cell 033 is disconnected,
The electrical connection between the single cell C32 and the single cell 034 is C13 and C23.

This is done via a single cell called C43, and overall the performance drop is very small.

According to the above embodiment, a plurality of stacks 27 are arranged in a row in the same direction, and the cells 26 are electrically connected to each other via metal plates 29 or the like at a plurality of locations in the longitudinal direction of the stack. After a plurality of 2-6 are connected in parallel, they are connected in series.

Therefore, even if one cell breaks, the current will flow through the other cells 26 arranged in parallel, making it virtually unaffected by batteries with inferior performance, dramatically improving the quality of the battery group. improves.

In addition, the dramatic improvement in quality has made it possible to assemble vast numbers of batteries, creating the possibility of large-scale power generation plants.

Note that the cylindrical solid electrolyte fuel cell according to the present invention is not limited to the one described in the above embodiment, but may be one shown in FIGS. 4 and 5. Here, in FIG. 4, the stack rows 28 are arranged so that the direction of current flow is alternately reversed one row at a time,
The stack rows 28 have a structure in which the left and right stack rows are alternately connected to each other. Here, the stack rows 28 are arranged in opposite directions one by one, and the cells at both ends of the stack row in the longitudinal direction are electrically connected to the adjacent stack rows by the metal plates 29 or the like alternately on the left and right. Therefore, the circuit becomes an equivalent circuit shown in FIG. That is, a plurality of stack columns 29
In this case, cells are connected in parallel and in series to form a battery group.
This battery group constitutes a power generation module 30 further connected in series.

Note that 31 in the figure is a support stand that supports the stack rows 28. By adopting the above configuration, the current is A-8-4
Flows through the high temperature range from 0-+D→E→F in the shortest length. However, the cylindrical 5OFG having the above structure has the following effects by connecting the stack rows 28 one after another under high temperature and extracting current.

(a) Electrical loss at the current extraction section is reduced and characteristics are improved.

(b) Cooling becomes unnecessary, allowing for high-density battery arrangement.

(c) Since cooling is not required, less heating energy is required and it is possible to recover thermal energy from waste gas.

[Effects of the Invention] As described in detail above, according to the present invention, the quality of the battery group is dramatically improved, the electrical loss at the current extraction part is reduced, the characteristics are improved, and the high-density It is possible to provide a cylindrical solid electrolyte fuel cell that has various effects such as battery arrangement and recovery of thermal energy from waste gas.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a cylindrical solid electrolyte fuel cell according to an embodiment of the present invention, Fig. 2 is a sectional view taken along the line X-X in Fig. 1, and Fig. 3 is an equivalent circuit of the same fuel cell. 4 is an explanatory diagram of a cylindrical solid oxide fuel cell according to another embodiment of the present invention, FIG. 5 is an equivalent circuit diagram of the same fuel cell, and FIG. 6 is an explanatory diagram of a conventional cylindrical solid oxide fuel cell. Fig. 7 is a cross-sectional view of the fuel cell, Fig. 8 is an explanatory drawing of the current extraction state of the fuel cell, and Fig. 9 is the relationship between the specific resistance of various metals and temperature. FIG. 21... Base tube, 22... Oxygen electrode, 23... Solid electrolyte membrane, 24... Interconnector, 25... Fuel electrode, 26... Cell, 27... Stack, 28
...Stack row, 29.30...Metal plate, 31...
・Power generation module. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 2 Figure 4 Figure 6 Figure 7 11118 Figure 9

Claims (1)

[Claims] A cylindrical solid electrolyte fuel cell characterized in that a plurality of base tubes each having a plurality of unit cells arranged in series are arranged in one row in the same direction, and the base tubes are electrically connected to each other at a plurality of points using a conductive material.