JPS63226885A - Fuel cell - Google Patents

Abstract

PURPOSE:To prevent a local cell from being formed and reduce the loss of an electrolyte and local corrosion by providing electrolyte plates for wet sealing and electrolyte plates for each electrode section face to face for individual gas passage holes at the periphery of a separator. CONSTITUTION:Wet sealing electrolyte plates 1b of passage holes 5, 7 feeding the oxidation gas and wet sealing electrolyte plates 1b of passage holes 6, 8 feeding the fuel gas are independently provided separately from each other at the periphery of each cell, and the wet sealing electrolyte plates lb of the passage holes are independent from electrolyte plates 1a for electrode sections. Thereby, even if the wet sealing electrolyte plates 1b of the passage holes 5, 7 of the oxidation gas and the wet sealing electrolyte plates 1b of the passage holes 6, 8 of the fuel gas are brought into contact with a separator 4 and the carbonate in the electrolyte plates 1b reaches the separator 4, no positive electrode section and negative electrode section are generated on the surface of the separator 4 to cause a short circuit. Accordingly, a local cell is prevented from being formed on the surface of the separator 4.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a fuel cell used in the energy sector that directly converts the chemical energy of fuel into electrical energy, and in particular relates to a molten carbonate type fuel cell. It is something.

[Prior Art] Among the molten carbonate fuel cells that have been proposed to date, there is one as shown in FIG.

That is, an electrolyte plate (tile) 1 made of porous material impregnated with molten carbonate is sandwiched between a cathode (oxygen electrode) 2 and an anode (fuel electrode) 3 from both sides, and an oxidizing gas OG is placed on the cathode 2 side. At the same time, fuel gas FG is supplied to the anode 3 side.
One cell (■) is one in which electricity is generated by the potential difference generated between the cathode 2 and anode 3 by supplying There is one that can be tightened with force to form a stack.

In a fuel cell having the above configuration, in the case of an internal manifold type as shown in the figure, there are supply side flow passage holes 5 and 6 for oxidizing gas OG and fuel gas "G" in the peripheral areas of the electrolyte plate 1 and separator 4. , a plurality of discharge side flow passage holes 7 and 8 are provided, and the electrolyte plate 1 is sandwiched between them so that the oxidizing gas OG and the fuel gas FG can flow.
．． The wet seal area around 8 is designed to prevent gas leakage.

A conventional electrolyte plate 1 in an internal manifold type fuel cell usually has the above-mentioned flow passage holes 5 and 6 for oxidizing gas and fuel gas in the wet seal part at the periphery, as shown in FIG.
7 and 8 are provided, and are integral with an electrode portion 8, which is a portion in contact with the electrodes.

[Problems to be Solved by the Invention] Therefore, in a local part of the separator 4, which is a metal surface that is in contact with the carbonate impregnated into the wet seal portion of the electrolyte plate 1, the flow passage hole 5 or 7 through which the oxidizing gas flows, An anode part and a cathode part are formed between the flow passage hole 6 or 8 through which the fuel gas flows and the gas passage of the separator 4 through which the oxidizing gas and the fuel gas flow, forming a local battery, and the carbonate is on the cathode side. It is deposited on the cathode gas (oxidizing gas) side.

As a result, the anode portion of the carbonate impregnated in the electrolyte plate 1 is pulled and drained by the precipitated carbonate, causing loss of electrolyte (carbonate). Furthermore, since the contact area between the wet seal portion A of the electrolyte plate 1 and the peripheral portion of the separator 4 is large, a reaction between the metal surface and the carbonate is likely to occur, and corrosion is likely to occur.

Therefore, the present invention aims to prevent the formation of local batteries and reduce electrolyte loss and local corrosion.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides an electrolyte plate having a size corresponding to the portion in contact with the electrode, and an electrolyte plate for wet sealing in each gas passage hole. are installed, the electrolyte plate is separated into the electrode portion and the wet seal portion of each channel hole, and the entire structure is placed in an N2 atmosphere.

[Function] Since the electrolyte plate for wet sealing is provided for each gas flow hole in the periphery of the separator independently from the electrolyte plate for the electrode section, the electrolyte plate for each gas flow hole is separated from each other.

Therefore, even if the carbonate in the wet seal electrolyte plate of each channel hole that comes into contact with the separator comes into contact with the separator, the movement of carbonate ions between the fuel gas side and the oxidizing gas side is suppressed, and a local battery is formed. Not done. Furthermore, since the area of the electrolyte plate that comes into contact with the separator is small, corrosion is less likely.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 show an embodiment of the present invention, and as shown in FIGS. 3 and 4, an oxidizing gas OG supply passage hole 5 and a fuel gas FG supply passage hole 5 are provided on one side of the peripheral portion. A plurality of side flow passage holes 6 are provided alternately, and a plurality of discharge side flow passage holes 7 for oxidizing gas OG and discharge side flow passage holes 8 for fuel gas FG are alternately provided on the other side of the periphery. Oxidizing gas OG with electrolyte plate 1 in between
This figure shows a case where the fuel cell is applied to an internal manifold type fuel cell in which the fuel gas FG and the fuel gas FG flow in parallel.

As shown in the figure, the fuel cell of the present invention includes flow passage holes 5 on the supply and discharge side for oxidizing gas and fuel gas, which are provided in the periphery of the separator 4;
Only in parts 6, 7, and 8, the web 1 to the electrolyte plate 1b for sealing are formed in a cylindrical shape, and the electrolyte plate 1a, which contacts the cathode 2 and the anode 3 on both sides, is connected to each electrode of the cathode 2 and anode 3. The electrolyte plate 1a for the electrode portion and each electrolyte plate 1b for wet sealing the flow path holes of each gas are made independent from each other, and the separator 4
There should be no electrolyte plates other than the above-mentioned electrolyte plates 1b around the area.

When assembling a fuel cell, both sides of a small electrolyte plate 1a for electrode parts are sandwiched between a cathode 2 and an anode 3 as in the conventional method shown in FIG. One cell is stacked in multiple layers with a separator 4 in between so that fuel gas flows through each side, and an independent cylindrical electrolyte is placed in the wet seal portion of each gas passage hole 5, 6, 7.8. Each plate 1b is installed, and the whole is housed in a container filled with N2 and placed in a N2 atmosphere.

As shown in FIGS. 1 and 2, the periphery of each cell consists of an electrolyte plate 1b for wet sealing in the flow passage hole 5 or 7 through which oxidizing gas flows, and a wet sealing electrolyte plate 1b in the flow passage hole 6 or 8 through which the fuel gas does not flow. The electrolyte plates 1b for sealing are completely separated and independent from each other, and as shown in FIG. Since the configuration is such that the wet sealing electrolyte plate 1b of the oxidizing gas flow path hole 5.7 and the fuel gas flow path hole 6,
The wet sealing electrolyte plates 1b of 8 come into contact with the separator 4, and the carbonate in each of these electrolyte plates 1b is released into the separator 4.
Even if the separator 4 comes into contact with the separator 4, an anode portion and a cathode portion will not be formed on the surface of the separator 4 and a short circuit will occur, and the formation of a local battery on the surface of the separator 4 is prevented. Furthermore, even if a local battery is formed, the electrolyte plate 1b for wet-sealing each channel hole in the peripheral area and the electrolyte plate 1a for the electrode part are independent as described above. There is no loss due to the electrolyte in the electrolyte plate 1a moving to the oxidizing gas flow path holes.

In addition, since the electrolyte plate 1b for wet sealing the channel holes of each of the scum is in contact with the periphery of the separator 4, the contact area between the electrolyte plate 1b and the metal separator 4 is small. , corrosion can be reduced accordingly.

In the above embodiment, the oxidizing gas and fuel gas supply side passage holes 5 and 6 are provided on one side of the peripheral portion, and the oxidizing gas and fuel gas discharge side passage holes 7 and 8 are provided on the opposite side of the peripheral portion. Although we have shown the case where the oxidizing gas and the fuel gas sandwich the electrolyte plate and flow in parallel, the same can be said of the case where the gas flows are counter-flow or cross-flow in addition to the above-mentioned parallel flow. It goes without saying that the shapes of the flow passage holes for each gas may be other than those shown in the drawings, and that various other changes may be made without departing from the gist of the present invention.

[Effects of the Invention] As described above, according to the fuel cell of the present invention, in an internal manifold type fuel cell, the electrolyte plate for wet-sealing the oxidizing gas passage hole provided in the peripheral portion and the fuel gas passage The electrolyte plates for hole wet sealing are completely separated from each other and made independent, and each of these electrolyte plates is also made independent from the electrolyte plate for the electrode section, and the entire structure is placed in an N2 atmosphere. , the oxidizing gas flow path hole and the fuel gas flow path hole can be completely separated, and a local battery is formed between the oxidation gas flow path hole, the fuel gas flow path hole, and the flow path in the metal separator. In addition to reducing electrolyte loss, the electrolyte plate for wet sealing the oxidizing gas flow path hole and the electrolyte plate for wet sealing the fuel gas flow path hole are completely separated. The area in contact with the metal separator can be reduced, reducing corrosion. Furthermore, the dependence of the seal on the smoothness of the separator surface can be reduced, and an increase in sealing efficiency can be expected. .

[Brief explanation of the drawing]

Fig. 1 is an example diagram showing the relationship between the electrolyte plate and the separator in the fuel cell of the present invention, Fig. 2 is an enlarged sectional view taken along ■-■ of Fig. 1, and Fig. 3 is a conventional internal manifold type molten carbonate salt. FIG. 4 is a cutaway side view showing an example of a type fuel cell, and FIG. 4 is a plan view of an electrolyte plate in a conventional fuel cell. 1, la, lb... electrolyte plate, 2... cathode, 3
...Anode, 4...Separator.

Claims (1)

[Claims] 1) The electrolyte plate and the separator have flow passage holes for supplying and discharging oxidizing gas and fuel gas in the periphery of the plate, and both sides of the electrolyte plate are held between the cathode and anode electrodes, so that the oxidation gas is formed on the cathode side. In an internal manifold type fuel cell formed by stacking gas and fuel gas to the anode side through a separator, the electrolyte plate is
It is characterized by having an electrolyte plate for the electrode part that the electrodes contact, and each electrolyte plate for wet sealing the flow path hole part of each gas separated and made independent from each other, and the whole being placed in an N_2 atmosphere. fuel cell.