JP3201201B2 - Stacked phosphoric acid 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 single cell in which a matrix holding phosphoric acid is sandwiched between a fuel electrode and an air electrode, and a fuel cell and air are supplied to supply DC gas by an electrochemical reaction. The present invention relates to a laminated phosphoric acid fuel cell to be obtained, and more particularly to an airtight structure of a reaction gas of a single cell.

[0002]

2. Description of the Related Art FIG. 2 is a partially exploded perspective view showing the structure of a unit cell of a conventional laminated phosphoric acid fuel cell. In this configuration, the fuel electrode includes a square fuel electrode base 4 having a plurality of fuel gas flow grooves 4a,
A fuel electrode electrode 5 having the same square shape as the above, and is made of a gas-impermeable carbon material separator 1A and separator edges made of the same gas-impermeable carbon material disposed on both side edges of one surface thereof. The fuel gas passage groove 4a is housed in a concave groove formed by the portion 2A and the packing 3A made of fluororesin. The air electrode is
A rectangular air electrode base material 9 having a plurality of air flow grooves 9a in a direction orthogonal to the fuel gas flow grooves 4a, and an air electrode 8 having the same square shape as the air electrode base material 9 are gas-impermeable. Into a concave groove formed by a separator 1B made of a conductive carbon material, a separator edge 2B made of a carbon material also made of a gas-impermeable material and a packing 3B made of a fluororesin, which are arranged at both side ends of one surface thereof. Are stored with the air flow groove 9a opened. The rectangular matrix 6 holding the electrolyte phosphoric acid has the same width in the direction of the fuel gas flow grooves 4a as the width of the air electrode 8 and the width in the direction of the air flow grooves 9a of the fuel electrode 5. The fluororesin insulating sheet 7 is formed to have the same outer dimensions as the separators 1A and 1B, and has a square shape substantially the same as the outer dimensions of the matrix 6 at the center thereof. Holes are formed. In this configuration, the separator 1A and the fuel electrode substrate 4
The reservoir plate 10 located between the matrix 6 and 5 serves to replenish the phosphoric acid lost in the matrix 6 as the operation proceeds.

FIG. 3 is a perspective view of a single cell formed by laminating the components shown in FIG. As shown in the figure, the outer periphery of the unit cell is a separator 1 incorporating a separator edge 2A.
A, an insulating sheet 7, and a fuel electrode base material 4 having a fuel gas flow groove 4 a on one of opposite sides of the unit cell, which is defined by the outer periphery of the separator 1 B incorporating the separator edge 2 B. The end face with the electrode 5 is exposed, and the end face between the air electrode base material 9 provided with the air flow groove 9a and the air electrode 8 is exposed on the other opposite side surface orthogonal to the side surface. Further, the airtightness between the fuel gas flowing through both electrodes and the air is maintained by the insulating sheet 7 made of fluororesin and the packings 3A and 3B. Further, the anode electrode 5, the anode substrate 4, the separator 1A, and the separator edge 2A are in an electrically conductive state, and the cathode electrode 8, the cathode electrode 9, the separator 1B, the separator edge 2B, Is electrically conductive, the electrical insulation between the two electrodes is maintained by the fluororesin insulating sheet 7 and the packings 3A and 3B.

[0004] Accordingly, the single cell constructed as described above is stacked to form a stacked phosphoric acid fuel cell, and
A fuel gas supply manifold, a fuel gas discharge manifold, an air supply manifold, and an air discharge manifold are incorporated, and the fuel gas is supplied to the fuel gas supply manifold.
a, and air is supplied to the air supply manifold to flow through the air flow groove 9a, so that DC power can be obtained by an electrochemical reaction.

[0005]

If a stacked phosphoric acid fuel cell is formed by using the single cell constructed as described above, a predetermined power generation can be performed, and therefore, it is often employed in various power generation devices. I have. However, even in the stacked phosphoric acid type fuel cell in which the single cell is configured as described above, gas leakage occurs between the reaction gas systems flowing through both electrodes of the single cell with the progress of the power generation operation, and the stacking of the stacked phosphoric acid type fuel cell occurs. The service life of the phosphoric acid type fuel cell may be reduced.

[0006] That is, the reaction gas discharged from the single cell contains water produced by the reaction in the form of water vapor, and may further contain a phosphoric acid mist generated from phosphoric acid held in the matrix 6. Acid mist is generated on the side of the reaction gas discharge side of the single cell or the separator edge 3A,
If it adheres to the end of 3B, these parts formed using the porous carbon material as a raw material will be corroded. When the corrosion of the edges of the separator edge portions 3A and 3B progresses and the gas tightness is lost, the discharge system of the reaction gas and the supply system or discharge system of the other reaction gas are formed at the corner of the single cell. Gas leaks between
There is a problem that local heating or the like occurs due to a reduction in the generated power and a reaction accompanying the inflow of the leaked gas, and the performance of the laminated phosphoric acid fuel cell is rapidly reduced.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and has as its object to prevent gas leakage caused by phosphoric acid corrosion of the end of a separator edge of a single cell,
It is an object of the present invention to provide a highly reliable laminated phosphoric acid fuel cell that can be operated stably for a long period of time.

[0008]

In order to achieve the above-mentioned object, in the present invention, a rectangular matrix holding phosphoric acid of an electrolyte is formed by using a fuel electrode base material having a fuel gas passage groove and a fuel electrode. A square fuel electrode composed of an electrode, a single cell sandwiched between a rectangular air electrode composed of an air electrode substrate having an air flow groove in a direction orthogonal to the fuel gas flow groove and an air electrode, and In a laminated phosphoric acid fuel cell formed by alternately laminating rectangular separators made of a gas-impermeable carbon material, the separator has a separator edge portion disposed on a side edge thereof and a packing made of fluororesin. By forming a concave groove for storing the fuel electrode on one surface so that the fuel gas flow groove is opened, and forming a concave groove for storing the air electrode on the other surface so that the air flow groove is opened, and But A separator having a thickness substantially the same as that of the separator and having the same square shape as the separator and housed in a rectangular hole provided in the center of an insulating sheet made of a fluororesin, at least both ends of the separator edge portion The part is formed of a fluororesin.

[0009]

As described above, in the laminated phosphoric acid type fuel cell, the single cell separator is formed so that the fuel electrode is formed on the entire surface by the separator edge portion provided on the side edge thereof and the packing made of fluororesin. A concave groove for storing the air electrode, and a concave groove for storing the air electrode on the other surface so that the air flow groove is opened.
If at least both ends of the separator edge are to be formed of a fluororesin, even if the reaction gas discharged from the single cell contains phosphoric acid mist, both ends where the separator edge is in contact with the reaction gas are Since it is formed of a fluororesin, corrosion by phosphoric acid mist does not occur. Therefore, gas leakage at this portion is prevented, and the use of the single cell thus formed allows the stacked phosphoric acid fuel cell to operate stably for a long period of time.

[0010]

FIG. 1 is a perspective view, partially exploded, showing the structure of a single cell of a first embodiment of a laminated phosphoric acid fuel cell according to the present invention. Components having the same functions as those of the single cell of the conventional example shown in FIG. 2 among the components of the single cell of the embodiment shown in FIG. . The difference between the present embodiment and the conventional example lies in the configuration of the separator edge portions 2A, 2B disposed on the side edges on both sides of the separators 1A, 1B. The separator edge portions 2A and 2B of the conventional example of FIG. 2 are made of an integrated gas-impermeable carbon material formed of a porous carbon material, whereas the separator of the embodiment shown in FIG. The edge portions 2A and 2B are composed of the fluororesin layers 11A and 11B disposed at both ends in the direction in which the electrodes to be held are exposed on the side surfaces of the single cell, and the gas-impermeable carbon material layers 12A and 12B disposed therebetween. It is characterized by being formed.

In this configuration, since both end surfaces of the separator edge portions 2A and 2B that come into contact with the discharged reactant gas are formed of the fluororesin layer, the phosphoric acid mist contained in the discharged reactant gas becomes Since it is not corroded even if it adheres to the end face, the occurrence of gas leakage due to the corrosion of the separator edges 2A and 2B by phosphoric acid as seen in the conventional laminated phosphoric acid fuel cell is prevented. Becomes

The separator edges 2A and 2B of the single cell of the above-described embodiment have the fluororesin layer 11 disposed on both end surfaces.
A, 11B and the gas-impermeable carbon material layers 12A, 12B disposed therebetween, but the separator edge portions 2A, 2B may be formed from an integrated fluororesin layer. Obviously, the same effects as in the above embodiment can be obtained without being shown.

[0013]

As described above, according to the present invention, the rectangular matrix holding the phosphoric acid of the electrolyte is formed into a square fuel comprising the fuel electrode base material having the fuel gas passage groove and the fuel electrode. A single cell, which is sandwiched between a pole and an air electrode base material having an air flow groove in a direction orthogonal to the fuel gas flow groove and a rectangular air electrode made of the air electrode, is formed of a gas-impermeable carbon. In a laminated phosphoric acid type fuel cell formed by alternately laminating square separators made of a material, the separator has a fuel electrode on one surface by a separator edge portion arranged on a side edge thereof and a packing made of fluororesin. A concave groove for storing the fuel gas flow groove is formed so as to be opened, and a concave groove for storing the air electrode is formed so as to open the air flow groove on the other surface, and the matrix is substantially the same as the matrix. Has thickness At least two end portions of the separator edge portion are formed of a fluororesin that is housed in a square hole provided at the center of an insulating sheet made of a fluororesin having the same square shape as the parator. Therefore, even if the exhaust gas of the reaction gas of the single cell contains phosphoric acid mist and touches the end face of the separator edge, corrosion of the separator edge is prevented, so that gas leakage due to corrosion is prevented. Thus, a highly reliable laminated phosphoric acid fuel cell that can be operated stably for a long period of time can be obtained.

[Brief description of the drawings]

FIG. 1 is a partially exploded perspective view showing the configuration of a single cell according to a first embodiment of a stacked phosphoric acid fuel cell of the present invention.

FIG. 2 is a partially exploded perspective view showing a configuration of a unit cell of a conventional laminated phosphoric acid fuel cell.

FIG. 3 is a perspective view of a single cell formed by laminating the conventional components shown in FIG. 2;

[Explanation of symbols]

 1A, 1B Separator 2A, 2B Separator edge 3A, 3B Packing 4 Fuel electrode base material 4a Fuel gas flow groove 5 Fuel electrode electrode 6 Matrix 7 Insulation sheet 8 Air electrode electrode 9 Air electrode base material 9a Air flow groove 10 Reservoir Plate 11A, 11B Fluororesin layer 12A, 12B Carbon material layer

Continuation of the front page (56) References JP-A-3-205764 (JP, A) JP-A-63-48767 (JP, A) JP-A-58-157063 (JP, A) JP-A-60-189869 (JP) JP-A-1-197968 (JP, A) JP-A-62-98570 (JP, A) JP-A-7-6773 (JP, A) JP-A-5-41225 (JP, A) 61-147461 (JP, A) JP-A-4-4565 (JP, A) JP-A-7-235318 (JP, A) JP-A-63-112768 (JP, U) JP2-30143 (JP, A) B2) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01M 8/02

Claims (1)

(57) [Claims] 1. A rectangular matrix comprising a fuel electrode base having a fuel gas flow channel and a fuel electrode, and a rectangular matrix holding a fuel gas phosphoric acid, and a rectangular matrix perpendicular to the fuel gas flow channel. A single cell sandwiched between an air electrode substrate having an air flow groove in the direction to be formed and a rectangular air electrode made of an air electrode is alternately formed with a rectangular separator made of a gas-impermeable carbon material. In the stacked phosphoric acid type fuel cell formed by stacking, the separator is provided with a separator edge portion provided on a side edge thereof and a packing made of a fluororesin, whereby the fuel gas flow groove is opened on one side of the fuel electrode. A concave groove for accommodating the air electrode on another surface so as to open the air flow groove, and the matrix has substantially the same thickness as the matrix. Before At least two end portions of the separator edge portion are formed of a fluororesin, which is accommodated in a rectangular hole provided at the center of an insulating sheet made of a fluororesin having the same square shape as the separator. A stacked phosphoric acid fuel cell characterized by the above-mentioned.