JPH05101835A - Fuel cell - Google Patents

Abstract

PURPOSE:To provide a fuel cell, which can distribute gas uniformly to gas lines from manifold holes without decreasing the effective area of the fuel cell. CONSTITUTION:Gas separator plates 5a, 5b are installed on both sides of a cell 1 having an anode 3 and a cathode 4 and are furnished with gas lines 6, 7 for supplying gas to the anode and cathode and with manifold grooves 10, 11 for supplying and exhausting the gas to/from the lines 6, 7. The depth of these grooves 10, 11 shall be greater than that of the lines 6, 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell, and more particularly to an internal manifold type fuel cell.

[0002]

2. Description of the Related Art A fuel cell directly converts chemical energy of a supplied gas into electric energy, and at present, a phosphoric acid fuel cell, a molten carbonate fuel cell, a solid electrolyte fuel cell. Such research is actively conducted, and high power generation efficiency is expected.

Generally, an external manifold system and an internal manifold system are adopted as the gas supply system to the fuel cell. The external manifold method is to provide a gas supply section for each cell on the outer wall surface of the battery stack.
Although the structure is simple, it is necessary to devise a method for sealing the gas on the wall surface of the battery. On the other hand, the internal manifold method is to provide a gas supply unit for each cell inside the stack.
The seal may be a seal between the battery component and the gas separation plate, but since a part of the battery surface is used as a manifold, the effective area of the battery is reduced.

In consideration of the above, in a phosphoric acid fuel cell operated at a relatively low temperature (around 200 ° C.),
In many cases, the external manifold system is adopted, and in the molten carbonate fuel cell operated at a slightly high temperature (around 650 ° C.), either one of the systems is adopted and the high temperature (10
In a solid oxide fuel cell that is operated at about 00 ° C),
In many cases, the internal manifold method is used because it is easy to seal.

By the way, in the conventional internal manifold type fuel cell, as shown in FIGS. 5 and 6, the manifold holes 30, 31, 32 and 33 are made as small as possible to prevent the effective area of the cell from being reduced. Gas separation plate 5
1,52 are used.

[0006]

However, since the gas separating plates 51 and 52 shown in FIGS. 5 and 6 have different distances from the manifold holes 30 and 32 to the inlets of the gas passages 38 and 44, the inlets thereof are different. There is a difference in the pressure applied in the vicinity,
The gas could not be evenly distributed to each of the gas channels 38 and 44. As a result, there is a problem in that the gas does not evenly spread on the electrode surface and the battery performance is not sufficiently exhibited.

Therefore, as shown in FIG. 7, the manifold holes 39 and 40 are transformed into elongated holes, and the manifold holes 39 and 4 are formed.
A gas separation plate 53 having a substantially uniform distance from 0 to the inlet of each gas flow channel 41 is used. However, since the proportion of the manifold holes 39 and 40 in the cell surface is large, the effective area of the battery is reduced, and as a result, the battery characteristics are deteriorated.

In view of the above circumstances, it is an object of the present invention to provide a fuel cell capable of uniformly distributing gas from a manifold hole to each gas flow path without reducing the effective area of the cell. ..

[0009]

In order to solve the above-mentioned problems, the fuel cell of the present invention has a gas separation plate disposed on both sides of a cell having an anode and a cathode. A gas flow path for supplying gas to the cathode,
In a fuel cell in which a manifold groove for supplying and exhausting gas to and from the gas channel is formed, the depth of the manifold groove is
It is characterized in that it is formed to be deeper than the depth of the gas passage.

[0010]

According to the above structure, since the depth of the manifold groove is formed to be deeper than the depth of the gas passage, the gas is not formed in the manifold groove formed deeper than the depth of the gas passage. Can be stored once. Therefore, the pressures applied to the inlets of the gas flow paths can be made substantially equal, so that the differential pressure in each gas flow path can be reduced.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be specifically described below with reference to FIGS. 1 is a schematic cross-sectional view showing a main part of a solid oxide fuel cell according to an embodiment of the present invention, and FIG. 2 is a plan view showing an upper surface of a gas separation plate in the fuel cell of FIG. This fuel cell has, for example, as shown in FIG. 1, a multilayer structure of a cell 1 and gas separation plates 5a and 5b.

The cell 1 is, for example, a solid electrolyte plate 2 made of a sintered body of zirconia stabilized with 8% yttria.
And anode 3 consisting of nickel zirconia cermet
And a cathode 4 made of a perovskite type oxide such as lanthanum manganate. The cell 1 has a size of, for example, 10 cm × 10 cm. The gas separation plates 5a and 5b are made of, for example, a heat resistant metal such as a nickel chromium alloy (Inconel 600, 601). As shown in FIG. 2, ribs 14 are integrally formed on the upper surface of the gas separation plate 5b to form the anode gas flow channel 6. Further, each manifold hole (anode gas supply side manifold hole 8, anode gas exhaust side manifold hole 9) and each manifold groove (anode gas supply side manifold groove 10, anode gas exhaust side manifold groove 11, shown by dots in the figure) Are provided respectively. The depth of the manifold grooves 10 and 11 is, for example, 2 mm, and the depth of each anode gas flow channel 6 is, for example, 1 mm.
As a result, the manifold grooves 10 and 11 were formed to be deeper than the depth of each anode gas flow channel 6. On the other hand, the lower surface of the gas separation plate 5a has substantially the same structure as that of FIG. 2 except that the cathode gas flow path 7 is provided so as to be orthogonal to the anode gas flow path 6, and therefore the description thereof is omitted.

The gas supply / discharge pipe 12 is made of a heat-resistant metal such as nickel-chromium alloy (Inconel 600, 601), for supplying / discharging gas to / from the cell 1, so that the gas separating plate 5 is used.
It is connected to a and 5b by welding or the like. Seal 13 at the interface between the gas separation plates 5a, 5b and the solid electrolyte plate 2
For example, a sealing material made of a non-conductive high viscosity melt such as Pyrex glass is used.

Next, the flow of the anode gas in the fuel cell having the above structure will be described with reference to FIG. First,
The gas sent from the manifold hole 8 flows through the manifold groove 10 and is distributed to each gas flow path 6. On this occasion,
After the gas is once stored in the manifold groove 10 formed deeper than the depth of the gas passage 6, the gas is evenly distributed to each gas passage 6. When flowing through the anode gas flow channel 6, a reaction is performed. Subsequently, the reacted gas flows through the manifold groove 11 and is discharged from the manifold hole 9.

On the other hand, the flow of the cathode gas is substantially the same as the flow of the anode gas except that it flows so as to be orthogonal to the anode gas, and therefore its explanation is omitted. The fuel cell configured as described above is hereinafter referred to as (A) cell. [Comparative Example] In place of the gas separation plates 5a and 5b, a gas separation plate 51 shown in FIG. 5 (the depths of the manifold grooves 34 and 35 and the gas passage 38 are the same, for example, 1 mm) is implemented. A fuel cell having the same structure as the example was used.

A fuel cell having such a structure is referred to below as (X)
It is called a battery. [Experiment 1] The relative gas flow rate ratio in each cell plane was examined using the battery (A) of the present invention and the battery (X) of the comparative example. The results are shown in FIG. The experiment was conducted by sandwiching a diazo photosensitive paper in place of the cell 1 and flowing ammonia-containing air at room temperature. The gas channel numbers on the horizontal axis are the gas channel numbers 6, 38 closest to the manifold holes 8, 30.
Was set as No. 1 and the farthest gas passages 6, 38 were set as No. 16.

From the results shown in FIG. 3, in the battery (A) of the present invention, the gas is uniformly distributed to each gas flow path 6, whereas in the battery (X) of the comparative example, each gas flow. It can be seen that there are variations in the gas distribution in the passage. [Experiment 2] The relationship between the current density and the voltage per unit cell in the battery (A) of the present invention and the battery (X) of the comparative example was investigated. The results are shown in FIG.

In the experiment, air was used as the oxidant gas, hydrogen was used as the fuel gas, and the utilization rate of oxygen (U _ox ) and the utilization rate of fuel (U _f ) were 10%. From the results shown in FIG. 4, it can be seen that the battery (A) of the present invention always rumors the cell voltage of the battery (X) of the comparative example. Further, as the current density increases, the cell voltage of the battery (X) of the comparative example decreases, whereas the battery voltage of the battery (A) of the present invention hardly decreases. ) In the battery, it can be seen that the cell characteristics are improved especially on the high current density side. This is probably because the gas is evenly distributed in the gas flow path. [Other Matters] In the above embodiment, the depth of the manifold groove was set to be about twice the depth of the gas passage, but the present invention is not limited to this. In the above embodiments, the solid oxide fuel cell was used as the fuel cell, but the fuel cell is not limited to this, and for example, a molten carbonate fuel cell or the like may be used. In the above-described embodiment, the gas flow paths 6 and 7 are provided with ribs 14.
However, the present invention is not limited to this, and the gas flow paths 6 and 7 are formed by using, for example, a corrugate made of a heat-resistant metal such as a nickel chromium alloy (Inconel 600, 601), a foam metal, or a conductive ceramic such as a lanthanum chromite. Can also be molded.

[0019]

According to the present invention described above, since the depth of the manifold groove is formed to be deeper than the depth of the gas passage, the manifold formed deeper than the depth of the gas passage. Gas can be temporarily stored in the groove. Therefore, the pressures applied to the inlets of the gas flow paths can be made substantially equal, so that the differential pressure in each gas flow path can be reduced. As a result, the gas can be uniformly supplied to each gas flow path, so that the gas is evenly distributed over the electrode surface, and the battery performance is sufficiently exhibited.

In addition, since the portion of the manifold groove excluding the manifold hole and the back seal portion associated therewith can be used for the battery reaction, the battery characteristics can be improved without reducing the effective battery area. ..

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a main part of a battery (A) according to an embodiment of the present invention.

FIG. 2 is a plan view showing an upper surface of a gas separation plate according to the battery (A) of the present invention.

FIG. 3 is a graph showing a relative gas flow rate ratio in each cell plane of the battery (A) of the present invention and the battery (X) of the comparative example.

FIG. 4 is a graph showing the relationship between the current density and the voltage per unit cell in the battery (A) of the present invention and the battery (X) of the comparative example.

FIG. 5 is a plan view showing a gas separation plate relating to a (X) battery of a comparative example.

FIG. 6 is a plan view showing a gas separation plate for a conventional fuel cell.

FIG. 7 is a plan view showing a gas separation plate for a conventional fuel cell.

[Explanation of reference numerals] 1 cell 5 gas separation plate 6 anode gas flow channel 7 cathode gas flow channel 10 anode gas supply side manifold groove 11 anode gas exhaust side manifold groove

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Shuzo Murakami 2-18 Keihan Hondori, Moriguchi Sanyo Electric Co., Ltd. (72) Inventor Toshihiko Saito 2-18 Keihan Hondori, Moriguchi Sanyo Electric Co., Ltd. Within

Claims (1)

[Claims] 1. A gas separation plate is arranged on both surfaces of a cell having an anode and a cathode, and a gas flow path for supplying gas to the anode and cathode and a gas supply / discharge for this gas flow path are provided in the gas separation plate. In the fuel cell in which the manifold groove is formed, the depth of the manifold groove is formed to be deeper than the depth of the gas flow path.