JPH05242899A - Direct internal reforming system molten carbonate type fuel cell - Google Patents

Abstract

PURPOSE:To provide a direct internal reforming system molten carbonate type fuel cell which can suppress the deterioration of a reforming catalyst and prolong the lifetime. CONSTITUTION:The anode side spacers 11, 11 are fixed on both sides of the top surface of a gas separation plate 6 along the flow direction of raw material gas in a direct internal reforming system molten carbonate type fuel cell arranging a reforming catalyst 9 inside the cell. This anode side spacer 11 consists of an electrolyte absorption part 11a consisting of a porous sintered body of plate-shaped Al2O3 as an electrolyte absorbing agent, and a stainless steel part 11b for preventing the electrolyte from entering from the manifold side provided on both ends of an electrolyte absorption part 11a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct internal reforming molten carbonate fuel cell, and more particularly to a seal portion of a gas separation plate.

[0002]

2. Description of the Related Art A molten carbonate fuel cell uses a cathode containing nickel oxide as a main component, an anode containing nickel as a main component, and an electrolyte plate composed of lithium aluminate and an electrolyte (lithium carbonate, potassium carbonate). It is manufactured by stacking a cell configured as above, a gas flow path plate, and a gas separation plate.

In the direct internal reforming molten carbonate fuel cell, a reforming catalyst is installed in the gas passage plate on the anode side to reform the fed gas such as methane to hydrogen gas, Used as fuel gas. Conventionally, this reforming catalyst is directly arranged in the anode side corrugated plate, which is the anode side gas flow plate.

[0004]

By the way, in the above-mentioned direct internal reforming molten carbonate fuel cell, a liquid electrolyte leached through the anode and its peripheral members or vaporized and scattered. The incoming gaseous electrolyte may adhere to the reforming catalyst and reduce the catalytic activity.

In particular, the liquid electrolyte has a larger amount of leaching than the gas electrolyte, so that the catalytic activity is easily lowered. Among them, the electrolyte leaching from the wet seal part falls on the surface of the spacer and falls on the corrugated surface, further permeates into the central part where the anode side corrugate is formed, and finally the electrolyte is present in the reforming catalyst. They are directly attached and cause a significant decrease in catalytic activity.

[0006] Such reduction in catalytic activity of the reforming catalyst causes
The direct internal reforming molten carbonate fuel cell has a problem of causing deterioration of cell characteristics and life characteristics. In view of the above problems, it is an object of the present invention to provide a direct internal reforming molten carbonate fuel cell capable of suppressing the deterioration of the reforming catalyst and extending the life of the cell.

[0007]

In order to achieve the above-mentioned object, the invention of claim 1 holds a cell in which an anode and a cathode are arranged on both surfaces of an electrolyte plate holding an electrolyte, and a reforming catalyst. In a battery in which a plurality of anode gas supply means for supplying the anode gas reformed by the reforming catalyst to the anode and a gas separation plate having a sealing portion for sealing the anode gas are stacked, a gas reforming catalyst In a direct internal reforming molten carbonate fuel cell in which the electrolyte is placed inside the cell, an electrolyte absorbing member for preventing the electrolyte from penetrating into the reforming catalyst is provided in the seal portion of the gas separation plate. It is characterized by being.

[0008]

[Function] Even when the electrolyte leaches out, the electrolyte absorbing member is provided in the seal part on the anode side of the gas separation plate, so the leached electrolyte is absorbed before reaching the reforming catalyst. It is absorbed by the member. This prevents the electrolyte from adhering to the reforming catalyst and maintains the catalytic activity.

[0009]

【Example】

[Embodiment] An embodiment of the present invention will be described below. 1 and 2 are views showing a direct internal reforming molten carbonate fuel cell of this embodiment. The direct internal reforming molten carbonate fuel cell has an electrolyte plate 1 made by a tape casting method of a slurry using lithium aluminate powder and an organic binder, and one surface of the electrolyte plate 1 Is provided with an anode 2 made of a nickel alloy porous sintered plate, and a cathode 3 made of a lithium nickel oxide porous sintered plate is provided on the other surface of the electrolyte plate 1. On the other surface side of the cathode 3, a stainless steel collector plate 4, a corrugate 5 on the cathode side, which has a corrugated plate shape and constitutes an oxidant gas passage, and a gas separation plate 6 are sequentially stacked.

On the other hand, on the other surface side of the anode 2, a current collector plate 7 made of nickel, and an anode side corrugate 8 having a corrugated plate shape and forming a fuel gas passage in a direction perpendicular to the cathode side corrugate 5 are provided. , And the gas separation plate 6 are sequentially stacked. Further, the anode-side corrugate 8 is filled and held with a pelletized Ni-based commercial catalyst as the reforming catalyst 9.

A unit cell 10 is constituted by the electrolyte plate 1, the anode 2, the cathode 3, both current collector plates 4 and 7, corrugates 5 and 8, and gas separation plates 6 and 6, and this unit cell 10 is formed. A battery stack is formed by stacking a large number of plates and tightening them in the stacking direction with upper and lower end plates (not shown). Here, as shown in FIG. 3, on both sides of the upper surface of the gas separation plate 6, along the flow direction of the source gas,
The anode side spacers 11, 11 are fixed. The anode side spacer 11 is an electrolyte absorbing portion 11a made of a plate-shaped porous sintered body of Al ₂ O ₃ which is an electrolyte absorbing agent.
And a stainless steel portion 11b for preventing the electrolyte from entering from both ends of the electrolyte absorbing portion 11a on the manifold side. On the other hand, on both sides of the lower surface of the gas separation plate 6, the cathode side spacer 1 made of stainless steel is provided along the flow direction of the oxidant gas (perpendicular to the flow direction of the source gas).
2 and 12 are fixed. Both spacers 11, 1
The outer side surface and the upper surface or the lower surface of 2 are wet seal parts 1 formed by bending the stainless steel plate.
It is covered by 3, 14. As a result, the gas separation plate 6 has the separator portion 15 for separating the anode 2 and the cathode 3 and the wet seal surfaces 16 and 17 formed by pressing the wet seal portions 13 and 14 against the electrolyte plate 1. Will have.

Further, the source gas supply section A has a source gas supply manifold, the fuel gas discharge section B has a fuel gas discharge manifold, the oxidant gas suction section C has an oxidant gas supply manifold, and the oxidant gas discharge section. Oxidant gas discharge manifolds are connected to the parts D (not shown). The raw material gas supplied from the raw material gas supply manifold to the back side of each anode 2 is reformed into a fuel gas by the reforming catalyst 9 and then supplied to the anode 2 to cause a cell reaction.

A battery stack was prepared by laminating four 250 cm ² size single cells configured as described above. Hereinafter, this battery stack is referred to as (A) battery stack. [Comparative Example] Instead of the anode side spacer 11,
A battery stack was produced in the same manner as in Example 1 except that a spacer made entirely of stainless steel was used.

Hereinafter, this battery stack is referred to as (X) battery stack. [Experiment] The battery characteristics and the life thereof were measured using the battery stack (A) of the present invention and the battery stack (X) of the comparative example. The results are shown in FIG. As the measurement conditions, the temperature was raised, and when the temperature reached 650 ° C, the raw material gas adjusted so that the ratio of the amount of methane gas to water vapor became 3.0 was made to flow into the anode side, and the reforming catalyst modified it. Quality and power was generated. At this time, power generation has a current density of 150 m.
The measurement was performed under A / cm ² , and the characteristics were measured after the battery characteristics became stable.

As is apparent from FIG. 4, (A) of the present invention
The battery characteristics of the battery stack and the (X) battery stack of the comparative example are substantially the same, but the battery characteristics of the (X) battery stack of the comparative example significantly deteriorate after 2000 hours. It was found that the (A) battery stack of the present invention can obtain stable characteristics even after 3000 hours. [Other Embodiments] Although not shown in the above embodiments, as the spacer on the anode side, as shown in FIG. 5, a groove 22 is formed in the spacer 21 and the groove 22 is filled with the electrolyte absorbent 23. It has been confirmed by an experiment that the same effect as that of the above-mentioned embodiment can be obtained even if it is used.

[0016]

As described above, according to the present invention, the electrolyte absorbing member provided in the seal portion of the gas separation plate absorbs the leaching electrolyte before reaching the reforming catalyst. It is possible to prevent the electrolyte from adhering to the high quality catalyst and maintain the catalytic activity. As a result, there is an effect that the life of the fuel cell can be extended.

[0017]

[Brief description of drawings]

[0018]

FIG. 1 is a schematic cross-sectional view of a battery.

[0019]

FIG. 2 is an exploded perspective view of a main part of a battery stack.

[0020]

FIG. 3 is a schematic view of a gas separation plate incorporating a spacer according to the present invention.

[0021]

FIG. 4 is a diagram showing battery life characteristics.

[0022]

FIG. 5 is a detailed view of an anode side spacer.

[0023]

[Explanation of symbols]

 1 Electrolyte Plate 2 Anode 3 Cathode 6 Gas Separation Plate 8 Anode-side Corrugated Plate 9 Reforming Catalyst 11a Electrolyte Absorption Part 11b Stainless Part 13 Wet Seal Part

Front page continuation (72) Inventor Masato Nishioka 2-18 Keiyo Hondori, Moriguchi Sanyo Electric Co., Ltd. (72) Inventor Toshihiko Saito 2-18 Keihan Hondori, Moriguchi Sanyo Electric Co., Ltd.

Claims (1)

[Claims] 1. A cell in which an anode and a cathode are arranged on both sides of an electrolyte plate holding an electrolyte, and an anode gas which holds a reforming catalyst and supplies the anode gas reformed by the reforming catalyst to the anode. In a battery in which a plurality of supply means and a gas separation plate having a seal portion for sealing the anode gas are stacked, a direct internal reforming molten carbonate fuel cell in which a gas reforming catalyst is arranged inside the cell, The seal portion of the gas separation plate is provided with an electrolyte absorbing member for preventing the electrolyte from penetrating into the reforming catalyst. A direct internal reforming molten carbonate fuel cell. ..