JP5932587B2 - Electrochemical equipment - Google Patents

Description

  Embodiments of the present invention relate to electrochemical devices.

  For example, an electrochemical cell used in an electrochemical device such as a solid electrolyte fuel cell (SOFC) is formed by sandwiching an electrolyte membrane between two types of electrodes that perform an oxidation reaction and a reduction reaction. It is necessary to efficiently supply the gas necessary for the electrode reaction and discharge the gas generated at the electrode.

  For example, when a flat electrochemical cell is used, the electrochemical cell, current collector, separator, end plate, etc. are stacked and tightened with bolts and nuts, so there is a gap between each member. If another member is sandwiched between the members, a gas leak occurs in which the oxidizing agent and the reducing agent flowing through the gap leak from the gap, and so-called cross leak occurs in which the gases are mixed together, resulting in a decrease in power generation efficiency. There is a problem.

  In order to prevent this cross leak, a sealing structure has been proposed in which the side edges of the electrochemical cell and the current collector are filled with a sealing material and sealed.

JP 2010-55951 A

  However, in the case of the conventional seal structure, the electrochemical cell is directly stacked on other members, so that the electrochemical cell is easily damaged when assembled, so that the side edges of the electrochemical cell and the current collector are blocked. Since it is necessary to fill the sealing material, a technique is required for filling the sealing material, and once the sealing material is solidified, there is a problem that it is difficult to remove.

  The problem to be solved by the present invention is to provide an electrochemical device that can be incorporated and removed without damaging the electrochemical cell with a simple structure, and that can efficiently operate the electrochemical cell by preventing gas leakage. It is to be.

The electrochemical device of the embodiment includes an electrochemical cell, a cell holder, a gasket, a separator, and a sealant. The electrochemical cell includes an electrolyte membrane, an oxygen electrode provided on one surface of the electrolyte membrane, and a hydrogen electrode provided on a surface opposite to the oxygen electrode across the electrolyte membrane. The cell holder has a first opening having an inner diameter that can be loosely fitted to an outer edge portion of the electrochemical cell, and the electrochemical cell is inserted into the first opening. The gasket has a second opening formed with an inner diameter narrower than the first opening in order to expose the electrode while covering the surface of the cell holder and a part of the surface of the electrochemical cell; It is arranged for sealing on each surface of the cell holder and the electrochemical cell. The separator supplies a corresponding gas medium to each electrode of the electrochemical cell exposed from the second opening of the gasket. The sealing agent is filled or applied so as to fill a gap between the electrochemical cell, the cell holder, and the gasket.

  According to the present invention, the electrochemical cell can be incorporated and removed without damaging it with a simple structure, and the electrochemical cell can be operated efficiently by preventing gas leakage.

It is a longitudinal section showing the composition of the electrochemical device of one embodiment. It is a disassembled perspective view which shows the principal part of an electrochemical apparatus. It is a top view which shows the principal part of an electrochemical apparatus. It is XX sectional drawing of the electrochemical apparatus of FIG. It is sectional drawing which shows 2nd Embodiment.

Hereinafter, embodiments will be described in detail with reference to the drawings.
As shown in FIGS. 1 to 4, the electrochemical device of this embodiment includes an end plate 15a, an insulating sheet 17a, a separator 13a (hydrogen electrode side), a gasket 19a as a sheet-like sealing material, a current collector 14a, The electrochemical cell 10, the current collector 14b, the gasket 19b, the separator 13b (oxygen electrode side), the insulating sheet 17b, and the end plate 15b are stacked, and bolts 16a are passed through holes provided at the edges of the respective members. Tightened and fixed.

  This electrochemical device electrochemically reacts a reducing agent such as hydrogen with an oxidizing agent such as oxygen to obtain electric energy and water vapor, or reduces water vapor etc. by electrolysis at one electrode and at the opposite electrode. It is an apparatus provided with the electrochemical cell 10 which discharge | releases oxygen ion. A plurality of electrochemical cells 10 may be combined.

  The electrochemical cell 10 has a flat plate shape in which electrodes (hydrogen electrode 12a, electrolyte membrane 12x, oxygen electrode 12b) are formed on one side of a hydrogen electrode porous substrate 11 that is a support substrate. The electrochemical cell 10 does not hinder the effect even if the supporting base material is used as another member of the hydrogen polar porous base material 11.

  That is, the electrochemical cell 10 includes an electrolyte membrane 12x, an oxygen electrode 12b as an oxygen electrode provided on one surface of the electrolyte membrane 12x, and a surface opposite to the oxygen electrode 12b across the electrolyte membrane 12x. And a hydrogen electrode 12a as a hydrogen electrode.

  The separators 13a (hydrogen electrode side) and 13b (oxygen electrode side) are provided at, for example, a portion in contact with each electrode in order to perform two roles of supply of the reaction gas to each electrode and equal current collection from the entire electrode surface. It has gas supply grooves (indicated by broken lines in FIG. 1) carved on the electrode contact surface at an appropriate pitch.

  The reactive gas is supplied to the electrode through the gas supply groove, while the top of the groove: the portion in contact with the electrode is in close contact with the electrode via the current collectors 14a and 14b, and power is supplied to the electrochemical cell 10 from the outside. Alternatively, the electric power is taken out from the electrochemical cell 10.

  The adhesion between the current collectors 14a, 14b and the cell electrode surface is such that the electrochemical cell 10, separators 13a, 13b and current collectors 14a, 14b are vertically moved by a plurality of bolts 16a and nuts 16b via end plates 15a, 15b. Secure by tightening.

  It is desirable to use as many bolts 16a as possible (8 to 12 bolts) at the same interval around the cell as long as the workability is not impaired.

  Further, in order to insulate the end plate 15a and the current collector 14a, and the end plate 15b and the current collector 14b, the insulating plates 17a and 17b are interposed therebetween. This element of the insulating sheet 17 is not essential.

  The cell holder 18 has a frame shape and is arranged so as to cover the periphery of the electrochemical cell 10. The cell holder 18 in this example has substantially the same thickness as the electrochemical cell 10.

  That is, the cell holder 18 has an opening 18a as a first opening having the same inner diameter as the outer edge of the electrochemical cell, and the electrochemical cell 10 is inserted (freely fitted) into the opening 18a. is there.

  Since the electrochemical cell 10 is inserted (freely fitted) into the opening 18 a of the cell holder 18, a slight gap is generated between the cell holder 18 and the electrochemical cell 10. For this reason, the gap is filled with a filler 21 as a sealing material. The filler 21 is applied so as to fill the gap between the cell holder 18 and the gaskets 19a and 19b.

  That is, the filler 21 is filled or applied so as to seal (fill) the gaps between the electrochemical cell 10, the cell holder 18, and the gaskets 19a and 19b.

  As the filler 21, glass that melts near the operating temperature, ceramics or glass powder (preferably having an average particle size of 1 μm or less) that does not react or melt with the glass or peripheral members at the operating temperature were mixed. Use materials. In this example, for example, glass paste or the like is used as the mixed material.

  The electrolyte membrane 12x is provided as a dense layer having a certain width and not participating in the reaction on the surface of the electrochemical cell 10 on the oxygen electrode 12b side.

  The gasket 19a is disposed at a portion in contact with the separator 13a on the hydrogen electrode side. The gasket 19a is a sheet having the same size as the separator 13a and formed into a frame shape. The gasket 19b is disposed at a portion in contact with the separator 13b on the oxygen electrode side. The gasket 19b is a sheet having the same size as the separator 13b and formed into a frame shape.

  These gaskets 19a and 19b have the same width as the outer shape of the cell holder 18 and have a frame shape with an opening 19c opened so as to expose the electrolyte membrane 12x of the electrochemical cell 10.

  That is, the gaskets 19a and 19b are openings as second openings formed with an inner diameter narrower than the opening 18a in order to expose the electrodes while covering the surface of the cell holder 18 and a part of the surface of the electrochemical cell 10. 19c, which is disposed on each surface of the cell holder 18 and the electrochemical cell 10 for sealing.

  The separators 13a and 13b are provided with gas supply grooves 24. Gas groove covers 20a and 20b are respectively provided at portions where the gas supply groove 24 and the gaskets 19a and 19b are in contact with each other, and the surfaces where the gaskets 19a and 19b and the gas supply groove 24 are in contact with each other are made smooth. .

  That is, the separators 13a and 13b are grooves (gas supply grooves) for supplying the corresponding gas medium to the electrodes (hydrogen electrode 12a and oxygen electrode 12b) of the electrochemical cell 10 exposed from the openings 19c of the gaskets 19a and 19b. 24) is formed.

  Under the operating conditions of the electrochemical cell 10, the oxygen electrode 12b and the separator 13b (oxygen electrode side) and the electrical contact between the hydrogen electrode 12a and the separator 13a (hydrogen electrode side) are ensured while ensuring gas sealing at the end. To increase the thickness of the cell holder 18 under the same operating conditions as the thickness of the center of the electrochemical cell 10 (oxygen electrode 12b + electrolyte membrane 12x + hydrogen electrode 12a) plus the thickness of the current collectors 14a, 14b on both sides. The thicknesses of the gaskets 19a and 19b plus the thickness are preferably substantially the same (preferably the difference between the two is 0.1 mm or less).

  In tightening at the time of assembly, it is desirable that the gaskets 19a and 19b and the current collectors 14a and 14b contract according to pressure to provide a certain degree of robustness with respect to ensuring gas sealing performance and electrical contact.

  As the current collectors 14a and 14b whose thickness can be adjusted, for example, gold / silver mesh, felt, punching metal, or the like is used so as to have an appropriate thickness. You may adjust beforehand so that it may become suitable thickness.

  Furthermore, the contact resistance can be further reduced by adopting a structure that expands or expands at the use temperature of the electrochemical cell 10.

  In addition to the materials listed above, each electrode material or a metal paste with strong oxidation resistance (such as gold or silver) and a foaming substance (such as shirasu balloon, pearlite, fly ash) are mixed. Is mentioned. The mixing ratio of the foaming substance is desirably 1 to 20% (preferably 5 to 10%).

  Moreover, when the end face where the electrochemical cell 10 and the cell holder 18 come into contact is filled with the filler 21, it is possible to effectively prevent the reaction gas from leaking (cross leak) at the end of the electrochemical cell.

  As described above, according to the first embodiment, after the electrochemical cell 10 is mounted in the opening 18a of the cell holder 18, the opening 18a of the cell holder 18, the outer edge portion of the electrochemical cell 10, and the gaskets 19a and 19b. By filling or applying the filler 21 so as to fill the gap, gas leakage to the inside and outside of the apparatus can be prevented, and airtightness and electrical insulation of various gas flow paths can be maintained. In addition, since the filler 21 is not applied to the bolts 16a and the holes, the assembling work is easy, and it is possible to remove (disassemble) once assembled as a device.

  Further, the cell holder 18 and the separators 13a and 13b are provided with gas manifolds for supplying and discharging gas to and from the oxygen electrode 12b and the hydrogen electrode 12a, and the constituent members are brought into close contact with the cell holder 18 and the separators 13a and 13b. By providing a hole for the bolt 16a and integrating the hole for the bolt 16a and the gas manifold, a good gas sealing property can be obtained with a simple structure.

  As a result, the electrochemical cell can be incorporated and removed with a simple structure without damaging it, and gas leakage can be prevented and the electrochemical cell can be operated efficiently.

Next, a second embodiment will be described with reference to FIG.
In FIG. 1, the filler 21 is directly filled in the gap between the outer edge portion of the electrochemical cell 10 and the opening of the cell holder 18, but in the second embodiment, as shown in FIG. 5, the outer edge of the electrochemical cell 10. The part is covered with the cell end cover 22 from three sides of the cell end face and the two electrode faces.

  The cell end cover 22 covers the outer surface and part of the front and back surfaces of the electrochemical cell 10 and has a U-shaped cross section. Similarly to the separators 13a and 13b, the cell end cover 22 is formed of a stable metal or glass / ceramics that does not react with the reaction gas supplied to the electrochemical cell 10 and peripheral members under operating conditions.

  This cell end cover 22 suppresses the influence of the edge smoothness and thickness of the electrochemical cell on the gas sealability by adjusting the smoothness and thickness uniformity of the end face more strictly than the electrochemical cell 10, Higher robustness can be given.

  Between the cell end cover 22 and the cell holder 18, there is disposed a seal layer 23 composed of a mixture of a structural material that does not melt at the operating temperature of the electrochemical cell and a sealing material that melts at the operating temperature. Thereby, the gas-seal property between members can be further strengthened.

  As described above, according to the second embodiment, the end portion of the electrochemical cell 10 is protected by the cell end portion cover 22, and the gap between the cell end portion cover 22 and the cell holder 18 is filled with the filler 21 (sealant). By using the seal structure filled with, good power generation performance can be obtained while suppressing gas leakage under high temperature and high pressure use conditions.

  In other words, in this seal structure, the cell end cover 22 and the cell holder 18 are composed of a mixture of a structural material that does not melt at the operating temperature of the electrochemical cell 10 and a sealing material that melts at the operating temperature. By providing the sealing layer 23 or by disposing the filler 21 on the end surface where the cell end cover 22 and the cell holder 18 are in contact with each other, it is possible to ensure a higher gas sealing property.

  In each of the sealing structures described above, the difference between the thickness of the electrochemical cell 10 or the cell end cover 22 adjacent to the cell holder 18 and the thickness of the cell holder 18 is 0.1 mm or less, thereby further ensuring gas sealing performance. Can be secured.

  Although the embodiment of the present invention has been described, this embodiment is presented as an example and is not intended to limit the scope of the invention. The novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 10 ... Electrochemical cell, 11 ... Hydrogen electrode porous base material, 12a ... Hydrogen electrode, 12b ... Oxygen electrode, 12x ... Electrolyte membrane, 13a, 13b ... Separator, 14a ... Current collector, 15a, 15b ... End plate, 16a ... Bolt, 16b ... nut, 17a, 17b ... insulating sheet, 18 ... cell holder, 18a ... opening, 19a, 19b ... gasket, 19c ... opening, 20a ... gas groove cover, 21 ... filler, 22 ... cell end cover, 23 ... Seal layer, 24 ... Gas supply groove.

Claims (5)

A flat plate electrochemical cell having an electrolyte membrane, an oxygen electrode provided on one surface of the electrolyte membrane, and a hydrogen electrode provided on a surface opposite to the oxygen electrode with the electrolyte membrane interposed therebetween When,
A cell holder having a first opening with an inner diameter capable of loosely fitting the outer edge of the electrochemical cell, and having the electrochemical cell inserted into the first opening;
In order to expose the electrode while covering the surface of the cell holder and a part of the surface of the electrochemical cell, the cell holder has a second opening formed with an inner diameter narrower than the first opening. And a gasket arranged for sealing on each surface of the electrochemical cell;
A separator for supplying a corresponding gas medium to each electrode of the electrochemical cell exposed from the second opening of the gasket;
An electrochemical device comprising a sealing agent filled or applied so as to fill a gap between the electrochemical cell, the cell holder, and the gasket.   The electrochemical device according to claim 1, wherein the sealing agent is filled between an end surface of an outer edge of the electrochemical cell and an end surface of the opening of the cell holder. A cell end cover that is formed in a U-shaped cross section and covers a part of the outer surface and front and back surfaces of the electrochemical cell is disposed between the electrochemical cell and the cell holder,
3. The electrochemical device according to claim 1, wherein the sealing agent is filled or applied in a gap between each of the electrochemical cell, the cell end cover, the cell holder, and the gasket.   The electrochemical device according to any one of claims 1 to 3, wherein the sealant is composed of a mixture of a material having a structure that does not melt at the operating temperature of the electrochemical cell and a sealant that melts at the operating temperature. The electrochemical device according to claim 3 or 4, wherein the sealing agent is filled in a gap between the cell end cover and the cell holder.

Images