JPH02181368A - Molten carbonate fuel cell - Google Patents

Abstract

PURPOSE:To keep cell performance high over a long period of time by installing two stage separator sealing parts on the contact surface with an electrolyte plate and an electrode and by installing an electrolyte holding groove in the separator sealing part, directly under the end of the electrode, between both sealing parts. CONSTITUTION:An upper stage sealing part 4 is installed on the contact surface of a separator 1 with an electrolyte plate 3, and a lower stage sealing part 5 is also installed on the contact surface of the separator 1 with an electrode 2. An electrolyte holding groove 6 is formed in the whole periphery directly under the end of the electrode 2 between the upper stage sealing part 4 and the lower stage sealing part 5. During operation, an electrolyte flowing out from the electrolyte plate 3 tends to enter the inside of the separator 1 but is held in the electrolyte holding groove 6. Moreover, since the electrode 2 is supported with the lower stage sealing part 5, the electrolyte can not penetrate into the separator 1. The corrosion of the inside of the separator 1 is prevented and cell performance is kept high over a long period of time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a molten carbonate fuel cell, and particularly to a structure of a fuel cell suitable for preventing corrosion inside a separator.

[Conventional technology]

The conventional molten carbonate fuel cell is disclosed in Japanese Patent Application Laid-Open No. 60-9156.
As described in Publication No. 7, it consists of a separator, an electrode, and an electrolyte plate, and the outer periphery of the electrolyte plate is surrounded by a high-density ceramic frame to prevent electrolyte from leaking from the outer periphery.
The structure was designed to increase the electrolyte holding capacity of the electrolyte plate.

[Problem to be solved by the invention]

The above conventional technology prevents the electrolyte from flowing out, but it does not take into account the fact that the electrolyte may enter the separator from the boundary with the separator where the electrode end comes into contact with it, and this may cause internal corrosion of the separator. This has become a problem.

An object of the present invention is to prevent electrolyte from directly entering the separator from the electrolyte plate into the separator that is in contact with the electrolyte plate, and to maintain the electrolyte near the boundary even if the electrolyte enters from the boundary between the separator and the electrode end. However, it is an object of the present invention to provide a molten carbonate fuel cell having a structure that prevents corrosion inside the separator by preventing corrosion inside the separator.

[Means to solve the problem]

The above purpose is to provide a separator seal portion on the contact surface of the separator that contacts the electrolyte plate and the electrode in a molten carbonate fuel cell consisting of a separator, an electrode, and an electrolyte plate, and the separator seal portion contacts the electrolyte plate. It consists of two seal parts: an upper seal part, which is a surface, and a lower seal part, which is a surface that comes into contact with the electrode.The electrolyte is applied to the separator seal part around the entire circumference immediately below the electrode end between the upper seal part and the lower seal part. This is achieved by providing a retaining groove.

[For production]

By making the separator seal part that presses the electrolyte plate into two stages: the upper seal part, which is the surface that contacts the electrolyte plate, and the lower seal part, which is the surface that contacts the electrode, it is possible to prevent the electrolyte from directly entering the separator from the electrolyte plate. In addition, since the lower seal part of the two-stage seal part presses the electrode, the electrolyte does not enter into the separator.

In addition, the electrolyte holding groove provided all around the circumference just below the electrode end between the upper seal part and the lower seal part allows the electrolyte flowing out between the separator seal part and the electrode end to be retained in the electrolyte holding groove. without invading the inside.
Corrosion inside the separator can be prevented.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. 1st
The figure shows the structure of a basic unit of a molten carbonate fuel cell equipped with a two-stage seal and an electrolyte holding groove.

In FIG. 1, electrodes 2.degree. 2 are provided above and below an electrolyte plate 3, and separators 1, 1 are provided above and below the electrodes to form a basic unit.

An upper seal portion 4 is provided on the contact surface of the separator 1 that directly contacts the electrolyte plate 3, and a lower seal portion 5 is provided on the contact surface of the separator 1 that contacts the electrode 2. 5 is holding down the electrode 2.

An electrolyte holding groove 6 recessed into the separator 1 is formed along the entire circumference immediately below the end of the electrode 2 between the upper seal part 4 and the lower seal part 5.

During battery operation, the electrolyte impregnated in the electrolyte plate 3 is prevented from directly entering the separator l due to the upper seal part 4, and flows along the upper seal part 4 to the end of the electrode 2, from where it flows into the separator 1. It tries to get inside, but electrode 2
Since there is an electrolyte holding groove 6 just below the end of the electrolyte, it is held there. Further, since the lower seal portion 5 presses the electrode 2, the electrolyte does not enter the inside of the separator 1 from this portion.

According to this embodiment, by retaining the electrolyte in the electrolyte retaining groove 6 provided in the separator seal part, there is an effect of preventing the electrolyte from entering into the separator, and corrosion inside the separator can be prevented for a long period of time. Battery performance can be maintained without deterioration.

〔Effect of the invention〕

According to the present invention, the electrolyte that flows out from the electrolyte plate during operation tends to enter the separator, but this electrolyte can be retained in the electrolyte holding groove, and furthermore, since the electrode is held down by the lower seal part, the electrolyte Since no intrusion into the interior of the separator occurs, corrosion inside the separator can be prevented and battery performance can be maintained for a long time.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a basic unit of a molten carbonate fuel cell in which an electrolyte holding groove is provided in a separator seal portion comprising a two-stage seal portion according to an embodiment of the present invention.

Claims (1)

[Claims] In a molten carbonate fuel cell consisting of a separator, an electrode, and an electrolyte plate, a separator seal portion is provided on the contact surface of the electrolyte plate, the electrode, and the separator, and the separator seal portion includes an upper seal portion and an upper seal portion on the surface that contacts the electrolyte plate. It is characterized by having a two-stage seal part on the lower seal part of the surface that comes into contact with the electrode, and an electrolyte holding groove is provided in the separator seal part around the entire circumference immediately below the electrode end between the upper seal part and the lower seal part. molten carbonate fuel cell.