EP-4738485-A1 - ELECTROCHEMICAL DEVICE

EP4738485A1EP 4738485 A1EP4738485 A1EP 4738485A1EP-4738485-A1

Abstract

To provide an electrochemical device that easily achieves a thickness reduction of its insulating sealing member and can have improved performance. In an electrochemical device of an embodiment, a cell stack has an insulating sealing member installed between a first separator and a second separator and configured to seal a gap between the first separator and the second separator and electrically insulate the first separator and the second separator from each other. The insulating sealing member has a metal layer and an insulation layer stacked on the metal layer in a stacking direction. The insulation layer contains a glass paste base material having a lower glass transition temperature than an operating temperature of the cell stack and a filler material having a higher glass transition temperature than the operating temperature of the cell stack, and the filler material is dispersed in the glass base material.

Inventors

FUJIMOTO, AKIRA
SAWA, FUMIO
HIROSHIMA, Satoshi

Assignees

Kabushiki Kaisha Toshiba
Toshiba Energy Systems & Solutions Corporation

Dates

Publication Date: 20260506
Application Date: 20250714

Claims (4)

An electrochemical device comprising a cell stack including at least: electrochemical cells in each of which an electrolyte membrane is present between a fuel electrode and an oxygen electrode; and a first separator and a second separator which are formed of a metal material, the electrochemical cells being present between the first separator and the second separator in a staking direction, and the cell stack being configured such that a fuel electrode gas flows in the fuel electrodes, and an oxygen electrode gas flows in the oxygen electrodes, wherein the cell stack has an insulating sealing member installed between the first separator and the second separator and configured to seal a gap between the first separator and the second separator and electrically insulate the first separator and the second separator from each other, wherein the insulating sealing member has: a metal layer; and an insulation layer stacked on the metal layer in the stacking direction, and wherein the insulation layer includes a filler-containing part which contains a glass paste base material having a lower glass transition temperature than an operating temperature of the cell stack and a filler material having a higher glass transition temperature than the operating temperature of the cell stack, and in which the filler material is dispersed in the glass base material.
The electrochemical device according to claim 1, wherein the insulating sealing member includes an opening penetrating in the stacking direction, wherein the insulation layer further includes a filler-free part constituted by the glass paste base material, wherein the filler-containing part is provided to cover at least one of an edge portion located in a periphery of the metal layer and an edge portion located in a periphery of the opening, in a surface, of the metal layer, on which the insulation layer is stacked, and wherein the filler-free part is provided to cover a portion where the filler-containing part is not provided, in the surface, of the metal layer, on which the insulation layer is stacked.
The electrochemical device according to claim 1, wherein the filler material has an average particle size within a range of not less than 7 µm nor more than 13 µm.
The electrochemical device according to claim 1, wherein, in the insulation layer, a content ratio of the filler material in the filler-containing part is within a range of not less than 5 mass% nor more than 20 mass%.

Description

FIELD Embodiments of the present invention relate to an electrochemical device. BACKGROUND An electrochemical device has an electrochemical cell including a fuel electrode, an oxygen electrode, and an electrolyte membrane sandwiched between them. Out of electrochemical cells, a solid oxide electrochemical cell whose electrolyte membrane is a solid oxide is usable as at least one of a solid oxide fuel cell (SOFC) and a solid oxide electrolysis cell (SOEC). In the case where the solid oxide electrochemical cell is used as SOFC, for example, a fuel electrode gas (hydrogen, carbon monoxide, or the like) supplied to the fuel electrode and an oxygen electrode gas (oxygen, air, or the like) supplied to the oxygen electrode react through the electrolyte membrane under a high-temperature condition, resulting in the generation of electrical energy. On the other hand, in the case where the solid oxide electrochemical cell is used as SOEC, for example, a fuel electrode gas (water vapor) supplied to the fuel electrode is electrolyzed under a high-temperature condition, resulting in the production of hydrogen in the fuel electrode and the production of oxygen in the oxygen electrode. Typically, an electrochemical device includes a cell stack in which a plurality of electrochemical cells are stacked. The cell stack has a plurality of separators besides the plurality of electrochemical cells, and the plurality of electrochemical cells are each sandwiched between the plurality of separators in the stacking direction. In the cell stack, for an increase in power output and the like, the plurality of electrochemical cells are electrically connected through the separators. Further, the cell stack is sandwiched between a pair of end plates in the stacking direction, and the pair of end plates is fastened using, for example, fastening members such as bolts. The cell stack further has an insulating sealing member in each gap between the plurality of separators. The insulating sealing members are each, for example, a stack in which a metal layer and an insulation layer are stacked, and an inorganic material such as alumina or silica covers the metal layer to form the insulation layer. The insulating sealing members seal the gaps between the plurality of separators to prevent the leakage of the gases that are to be supplied to the electrochemical cells. In addition, the insulating sealing members electrically insulate the plurality of separators from each other to prevent the plurality of electrochemical cells from short-circuiting. SUMMARY OF THE INVENTION In the electrochemical device, the insulating sealing members are required to have high mechanical strength so as not to plastically deform to break when given a compressive load to obtain sealability. The insulating sealing members are further required to have excellent heat resistance to prevent their thermal deformation at the operating temperature of the electrochemical cells (for example, 600°C to 1000°C). Further, the insulating sealing members are required to have excellent insulation properties to prevent the occurrence of a short circuit. Besides, it is required to thin the insulating sealing members to meet a demand for the downsizing of the cell stack. However, conventionally, it has been sometimes difficult to obtain sufficient properties such as the insulation property while achieving the thinning of the insulating sealing members. For example, using gaskets as the insulating sealing members increases the thickness of the entire cell stack to make it difficult to downsize the cell stack. As a result, it is not easy to improve performance (power generation performance, electrolysis performance) while meeting the demand for the downsizing of the cell stack in the electrochemical device. Under such circumstances, a problem to be solved by the present invention is to provide an electrochemical device that can have improved performance while easily achieving the thinning of its insulating sealing member. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A is a side sectional view schematically illustrating an electrochemical device 1 according to a first embodiment (xz plane). FIG. 1B is a side sectional view schematically illustrating the electrochemical device 1 according to the first embodiment (yz plane).FIG. 2A is a horizontal sectional view schematically illustrating the electrochemical device 1 according to the first embodiment (Z1-Z1 part in FIG. 1A).FIG. 2B is a horizontal sectional view schematically illustrating the electrochemical device 1 according to the first embodiment (Z2-Z2 part in FIG. 1A).FIG. 3A is a horizontal sectional view schematically illustrating the electrochemical device 1 according to the first embodiment (Z3-Z3 part in FIG. 1A).FIG. 3B is a horizontal sectional view schematically illustrating the electrochemical device 1 according to the first embodiment (Z4-Z4 part in FIG. 1A).FIG. 4A is a schematic view illustrating the configuration of an insulatin