CN219419115U

CN219419115U - Module structure of solid oxide cell stack

Info

Publication number: CN219419115U
Application number: CN202320279719.8U
Authority: CN
Inventors: 马蒂·诺庞恩; J·斯特纽斯
Original assignee: Elkegen Co
Current assignee: Elkegen Co
Priority date: 2023-02-14
Filing date: 2023-02-14
Publication date: 2023-07-25
Anticipated expiration: 2033-02-14

Abstract

The present utility model relates to a module configuration of a solid oxide cell stack. The module configuration of solid oxide cell stacks is in a fuel cell system or an electrolyser cell system, each solid oxide cell stack comprising a unit cell (174) having a fuel side (100), an oxygen-enriched side (102) and an electrolyte material (104) between the fuel side and the oxygen-enriched side, each solid oxide cell stack (103) comprising a flow field plate (121) made of a material having a high electrical conductivity at high temperature, each solid oxide cell stack (103) having four angled structures, each solid oxide cell stack (103) comprising a gas seal structure (128) made of an electrically insulating material, the module configuration of solid oxide cell stacks having an internal gas distribution structure (127) for the inlet side and the outlet side of the fuel gas.

Description

Module structure of solid oxide cell stack

Technical Field

The present utility model relates to a module configuration of a Solid Oxide Fuel Cell (SOFC) stack or a module configuration of a Solid Oxide Electrolyzer Cell (SOEC) stack.

Background

Most of the energy in the world is produced by petroleum, coal, natural gas or nuclear energy. All these production methods have their particular problems, such as usability and environmental friendliness, of interest. In terms of environmental concerns, petroleum and coal in particular can cause pollution when they are burned. The problem with nuclear energy is at least the storage of spent fuel.

In particular, new energy sources, which are more environmentally friendly and have better efficiency than the above energy sources, for example, have been developed due to environmental problems. Fuel cells are a promising future energy solution, by which fuel energy, such as biogas, is converted directly into electricity via chemical reactions in an environmentally friendly process and in an electrolyzer which converts electricity into fuel.

Renewable energy production methods such as photovoltaic and wind energy face the problem of seasonal production variations because their power production is limited by environmental influences. In the case of overproduction, the production of hydrogen by water electrolysis is considered one of the energy storage options in the future. In addition, electrolysis cells can also be used to produce high quality methane gas from renewable biogas storage.

The present utility model relates to a module configuration of a Solid Oxide Fuel Cell (SOFC) stack or a module configuration of a Solid Oxide Electrolyzer Cell (SOEC) stack. The fuel cell reacts an input reactant fuel gas at the anode with a gaseous oxidant (oxygen) at the cathode to produce electricity. The electrolyzer reaction is opposite to that of a fuel cell, i.e. electricity is used to produce fuel and oxygen. SOFC and SOEC stacks include cell elements and separators stacked in a sandwiched manner, wherein each cell element is constituted by sandwiching an electrolyte, an anode side, and a cathode side. The reactant is directed by the flow field plate to the porous electrode.

As shown in fig. 1, the fuel cell includes a fuel side 100 and an oxygen-rich side 102 with an electrolyte material 104 therebetween. Here, this structure is referred to as a unit cell 174 (fig. 1, fig. 12). In a Solid Oxide Fuel Cell (SOFC), oxygen is supplied to the oxygen-rich side 102 and reduced to negative oxygen ions by receiving electrons from the cathode. The input stream is depleted of oxygen at the outlet side. Negative oxygen ions are transferred through the electrolyte material 104 to the fuel side 100 where they react with the fuel gas 108 to produce electrons, water, and typically carbon monoxide (CO) and carbon dioxide (CO) ₂ ) I.e., fuel off-gas 177. The anode and cathode are connected by an external circuit 111, the external circuit 111 comprising a load for the fuel cell, which extracts electrical energy from the system together with heat. The fuel cell reaction in the case of methane, carbon monoxide and hydrogen fuels is as follows:

anode: CH (CH) ₄ +H ₂ O＝CO+3H ₂

CO+H ₂ O＝CO ₂ +H ₂

H ₂ +O ^2- ＝H ₂ O+2e ^-

And (3) cathode: o (O) ₂ +4e ^- ＝2O ^2-

Net reaction: CH (CH) ₄ +2O ₂ ＝CO ₂ +2H ₂ O

CO+1/2O ₂ ＝CO ₂

H ₂ +1/2O ₂ ＝H ₂ O

In the electrolysis mode of operation (solid oxide electrolyzer cell (SOEC)) the reaction is reversed, i.e. heat and electrical energy from source 110 are supplied to the cell, where water and typically also carbon dioxide are reduced in the cathode side, forming oxygen ions which move through the electrolyte material 104 to the anode side where the oxidation reaction takes place. The same solid electrolyte cell can be used in SOFC and SOEC modes. In this case and in the context of the present description, the electrodes are typically named anode and cathode based on the fuel cell operation mode, whereas in pure SOEC applications the oxygen electrode may be named anode and the reactant electrode may be named cathode.

The solid oxide electrolyzer cell is operated at a temperature that allows high temperature electrolysis reactions to occur, typically between 500-1000 ℃, but temperatures other than the limits may be useful. These operating temperatures are similar to the conditions of an SOFC. The net cell reaction produces hydrogen and oxygen. The reaction with one mole of water at the anode with water reduction occurs as follows:

and (3) cathode: h ₂ O+2e ^- --->2H ₂ +O ^2-

Anode: o (O) ^2- --->1/2O ₂ +2e ^-

Net reaction: h ₂ O--->H ₂ +1/2O ₂

In Solid Oxide Fuel Cell (SOFC) and Solid Oxide Electrolyzer (SOE) stacks, commonly referred to herein as solid oxide cell stacks, are combined by stacking different cell layers, wherein the flow direction of the cathode gas is relative to the flow direction of the anode gas inside each cell and the gas between adjacent cells. Further, the cathode gas or the anode gas or both may pass through more than one cell before it is exhausted, and the multiple gas streams may be separated or combined after passing through the primary cell and before passing through the secondary cell. These combinations serve to increase current density and minimize thermal gradients across the cell and the entire cell stack.

SOFCs deliver a voltage of about 0.8V in normal operation, and SOECs deliver a voltage of about 1.3V. To increase the overall voltage output, the unit cells 174 are typically assembled into stacks in which the cells are electrically connected via flow field plates (also including: separator plates, interconnect plates, bipolar plates). The required voltage level determines the number of batteries required.

The bipolar plates separate the anode and cathode sides of adjacent cells and simultaneously enable electron conduction between the anode and cathode. The interconnect or bipolar plates are typically provided with a plurality of channels for the passage of fuel gas on one side of the interconnect plate and oxygen-enriched gas on the other side. The flow direction of the fuel gas is defined as the basic direction from the fuel inlet portion to the fuel outlet portion of the battery cell. Also, the flow direction of the oxygen-enriched gas is defined as the basic direction from the inlet portion of the cell to the outlet portion thereof.

Traditionally, cells are stacked on top of each other, with a complete overlap resulting in a stack with, for example, co-current flow, with all fuel and oxidant inlets on one side and all fuel and oxidant outlets on the opposite side. One feature that affects the temperature of the structure in operation is the steam reforming (steam reformation) of the fuel supplied to the cell. Steam reforming is an endothermic reaction and cools the fuel inlet edge of the cell.

The exit temperature of the exit gas is higher than the entrance temperature due to the exothermic nature of the electrochemical process. When endothermic and exothermic reactions are combined in the SOFC stack, a significant temperature gradient across the stack is created. The large thermal gradients cause thermal stresses in the stack, which are highly undesirable and which lead to differences in current density and electrical resistance. Thus, there is a thermal management problem with SOFC stacks: thermal gradients are reduced enough to avoid unacceptable stresses and electrical efficiency is maximized by uniform current density distribution.

The fuel cell stack or the electrolyzer cell stack of the prior art has tolerance variations in the thickness of the unit cell structure between the cell structures in the stack. For example, in a battery stack structure using a ceramic material, it is only convenient to measure thickness variation in micrometers in the prior art embodiments. This causes the flow conditions to be different between the cells and causes the cell voltage distribution in the cell stack structure to vary, which results in thermal gradients between the cells and reduced power density of the stack. Thus, the duty cycle of the stack is reduced, and the lifetime of the stack is shortened, the former increasing the capital cost of the stack per production power output, and the latter increasing the operating cost of the stack structure, e.g., reducing the replacement time of the stack in a fuel cell system, and increasing the electrical cost in the electrolyzer stack.

High temperature solid oxide cell stacks are a preferred conversion technology due to their extremely high efficiency in fuel cells and electrolysis modes. The inherent challenges associated with this technology also stem from the high temperatures, which challenge is corrosion of the materials causing an increase in the internal resistance of the structure, thereby reducing the power and hydrogen production capabilities of the fuel cell and electrolyzer, respectively. Corrosion problems can exist in multiple locations in the stacked structure, but are typically in the inclusion of multiple triple regions. In such material systems, for example, due to their good corrosion resistance and matching thermal expansion characteristics between other stacked materials, metal interconnect materials, typically made of ferritic stainless steel grades, can react with sealing structures, typically made of at least part of glass materials, by, for example, changing the crystalline structure of the metal or by changing the protective oxide structure of the metal surface (which ultimately may result in a direct path of fuel and oxygen mixing through planar oxidation of the steel material, causing serious damage to the structure).

Disclosure of Invention

The object of the present utility model is to improve the reliability and structure of a fuel cell stack or an electrolyzer cell stack. This is achieved by the modular construction of a solid oxide cell stack in a fuel cell system or an electrolyzer cell system.

According to one aspect, the present utility model provides a module construction of solid oxide cell stacks in a fuel cell system or an electrolyser cell system, each solid oxide cell stack comprising a unit cell having a fuel side, an oxygen-rich side and an electrolyte material between the fuel side and the oxygen-rich side, each solid oxide cell stack comprising a flow field plate made of a material having a high electrical conductivity at high temperature, each solid oxide cell stack having four angled structures, each solid oxide cell stack comprising a gas seal structure made of an electrically insulating material, the module construction of solid oxide cell stacks having an internal gas distribution structure for the inlet side and the outlet side of the fuel gas, the oxygen side gas transfer being based on an oxygen side gas transfer open structure, and the module configuration of the solid oxide cell stack includes end plates for current collection, and the unit cells, the flow field plates, and the gas seal structure are arranged in a stack in the form of a solid oxide cell stack between the end plates, the module configuration of the solid oxide cell stack is arranged in a 2 x N matrix, N being any natural number, and the module configuration of the solid oxide cell stack includes a fuel inlet manifold and a fuel outlet manifold between two adjacent solid oxide cell stacks, the fuel inlet manifold and the fuel outlet manifold forming a fuel manifold to deliver supplied fuel gas to and fuel off-gas from the solid oxide cell stack, and from the standpoint of fuel gas supply and fuel off-gas connection, the solid oxide cell stacks are arranged in parallel connection in the fuel manifold and the solid oxide cell stacks are arranged with a common oxygen side gas supply chamber and a common oxygen side exhaust gas chamber, the common oxygen side gas supply chamber being connected to an inlet side of an oxygen side gas transfer open structure, the common oxygen side exhaust gas chamber being connected to an outlet side of an oxygen side gas transfer open structure and the inlet manifold comprising gas flow holes of a controllable size opening to the solid oxide cell stacks for forming a uniform gas flow to the solid oxide cell stacks and the outlet manifold comprising gas flow holes of a controllable size opening to the solid oxide cell stacks for forming a uniform gas flow from the solid oxide cell stacks and the module configuration of the solid oxide cell stacks comprising a first gas seal, a first electrically insulating plate and a second gas seal between the fuel manifold and the solid oxide cell stacks and on the top side and the bottom side of the solid oxide cell stacks, the module configuration of the solid oxide cell stacks comprising a second electrically insulating plate 114 for connecting the solid oxide cell stacks and a compressed air end plate of each of the solid oxide cell stacks.

The modular construction of the solid oxide cell stacks includes means for controlling the size of the individual airflow apertures to create a uniform airflow between the solid oxide cell stacks.

The fuel manifold has an inlet pipe connection at a first end of the fuel manifold and an outlet pipe connection at a second end of the fuel manifold.

The air side seal structure includes a hard ceramic in a middle portion and a soft ceramic in an edge portion.

The fuel manifold and the cover portion of the solid oxide cell stack are made of at least one material having the same coefficient of thermal expansion.

The first electrically insulating plate is made of at least one dense material.

The second electrically insulating plate is made of at least one porous material.

The fuel manifold is made of ferritic steel.

The module configuration of the solid oxide cell stack includes a pair of at least two solid oxide cell stacks arranged electrically in a series connection.

The module configuration of the solid oxide cell stack includes X solid oxide cell stacks arranged in a series connection, where X is a natural number and satisfies 2N/x=y, where N and Y are natural numbers.

The module configuration of the solid oxide cell stacks includes compensation structures on the top side or the bottom side of the solid oxide cell stacks for compensating for height tolerances between the solid oxide cell stacks.

The module configuration of the solid oxide cell stack includes a gas tight structure in which the fuel manifold, the solid oxide cell stack, the first gas seal and the first gas seal, and the first and second electrically insulating plates are positioned, and the air side seal structure is sealed against the gas tight structure.

The modular construction of the solid oxide cell stack includes the compression structure inside the hermetic structure.

The modular construction of the solid oxide cell stack includes the compression structure located outside of the hermetic structure.

The modular construction of the solid oxide cell stack includes the fuel inlet manifold and the fuel outlet manifold that are joined together by welding to increase the rigidity and strength of the structure.

A benefit of the present utility model is a practical battery stack module configuration that can be sized according to the selected fuel cell or electrolysis cell application, thereby saving time, economic costs and assembly space.

Drawings

Fig. 1 shows a single fuel cell structure.

Fig. 2 shows a re-sold oxide cell structure.

Fig. 3 shows a first exemplary battery stack module configuration according to the present utility model from the front.

Fig. 4 shows a second exemplary battery stack module configuration according to the present utility model from the back side.

Fig. 5 shows a second exemplary battery stack module configuration according to the present utility model from the front.

FIG. 6 illustrates an exemplary manifold structure.

Fig. 7 shows a compressed structure inside the air side seal structure.

Fig. 8 shows a compression structure outside the air side seal structure.

Detailed Description

According to the utility model, the fuel cell stack or the electrolyzer stack comprises at least two single repeating structures. The single repeating structure includes: at least one electrochemically active cell structure comprising a fuel side, an oxygen-enriched side, and an electrolyte therebetween, the structure being disposed between at least two flow field plates, one flow field plate distributing oxygen-enriched gas in the oxygen-enriched side of the cell structure and the other flow field plate distributing fuel gas in the fuel side of the cell structure; and at least one sealing means sealing the gas atmosphere with its intended housing. The flow field plate has at least one inlet opening for fuel gas and/or oxygen-enriched gas and at least one outlet opening for spent fuel gas and/or oxygen-enriched gas. The flow direction of the fuel gas and the oxygen-enriched gas may be arranged to: a co-current configuration in which the two gases flow in substantially the same direction on each side of the unit cell; or a counter-current arrangement wherein the flow direction is substantially opposite between the fuel and the oxygen-enriched gas; or a total flow arrangement wherein the flow direction is substantially at a 90 ° angle between the fuel and the oxygen-enriched gas or in a combination thereof.

Fig. 2 shows a flow field plate 121 of a fuel cell stack. The complete fuel cell stack includes a plurality of flow field plates 121 placed one after the other in the manner shown. The plate in this embodiment is rectangular and symmetrical. A unit cell 174 including an electrolyte layer between an anode electrode and a cathode electrode is disposed between the flow field plates 121, approximately in the middle of the plates. The electrolyte element structure may be any suitable electrolyte element structure and will not be described in detail herein. The flow field plates 121 and the unit cells 174 are sealed with a gas seal structure 128, which is preferably made of a compressible material, such as a ceramic, mineral or glass material. The gas seal structure 128 according to the present utility model is compressed when the cells are assembled into a stacked structure. The two opposing flow field plates 121 and the unit cells 174 and the gas seal 128 therebetween form a single repeating structure.

The fuel cell stack configuration of fig. 2 includes restrictive orifices 135, 136 leading to the flow distribution region and to the flow outlet region. The gas seal 128 is compressed over the restricted orifices 135, 136. The restrictive orifices 135, 136 ensure that the fuel flow is evenly distributed throughout the active area of the fuel cell electrode by creating an additional pressure drop (pressure sink) to the flow path. The gas seal structure 128 also creates similar pressure loss conditions between the repeating structures of the fuel cell to ensure uniform flow distribution characteristics for each repeating structure of the fuel cell. The uniform flow distribution in the fuel cell stack also ensures uniform heat distribution conditions of the fuel cell stack, i.e., similar thermal gradients between cells in the stack. Thus, the duty ratio of the fuel cell stack is increased, and the fuel cell stack life becomes longer.

The purpose of the gas seal 128 is also to ensure that the oxidant and fuel do not mix directly without fuel cell reaction in the electrochemically active regions and that the fuel and oxidant do not leak out of the electrochemical cells and that adjacent electrochemical cells are not in electrical contact with each other and that the oxidant and fuel are supplied to the desired flow field plates 121. The flow field plates 121 are planar sheets made of metal alloys, ceramic materials, cermet materials, or other materials capable of withstanding the chemical, thermal, and mechanical stresses present in the fuel cell. The oxygen-enriched gas may be any gas or gas mixture that includes a measurable amount of oxygen.

A preferred method of manufacture for forming the contoured surface of the flow field plate 121 is as follows: methods using plastic deformation, such as stamping, forming, pressing, etc., in which the shape of the material is changed without adding or removing material; or methods of adding material such as welding, sintering and laser sintering or removal such as etching and machining. If the flow field material is brittle, other manufacturing methods may be used, such as extrusion, casting, printing, molding, and the like. The gas holes may generally be made in the same manufacturing step.

Each flow field plate 121 may be similarly fabricated in a stacked assembly configuration, thus requiring a desired number of plates of only one type to produce a fuel cell stack having a desired number of repeating unit cells 174. This simplifies the structure and eases the manufacture of the fuel cell.

Solid oxide electrolyzer stacks differ from solid oxide fuel cell stacks only in that electricity is used to produce fuel using a reaction that is the inverse of the fuel cell reaction described in the prior art.

The single largest energy consuming device in a fuel cell system is the blower or compressor used to supply air to the cathode compartments of the fuel cell stack. The power consumption of the air supply is proportional to the pressure level it requires to compress the air. Furthermore, in solid oxide electrolyzer systems, air is typically supplied to the anode in order to control the thermal balance of the electrolyzer stack and maintain a well-defined oxygen partial pressure across the anode chamber. One of the main sources of pressure loss in fuel cell and electrolyzer systems is the stack itself. The device is advantageously designed in such a way that the air side of the device has an open channel to the surrounding atmosphere.

First and second exemplary cell stack module configurations according to the present utility model in a fuel cell system or an electrolyzer cell system are shown in fig. 3 to 5. In a solid oxide cell stack module configuration, each stack (also referred to below as a solid oxide cell stack, fuel cell stack, or cell stack) includes a unit cell 174 having a fuel side 100, an oxygen-rich side 102, and an electrolyte material 104 between the fuel side and the oxygen-rich side. Each cell stack 103 includes a flow field plate 121 made of a material having high electrical conductivity at high temperatures. Preferably, high conductivity means an area specific resistance value of less than 0.1 ohm cm ² And preferably below 0.01 ohm cm ² . High temperature means a temperature value exceeding 400 ℃. Each stack has four angled structures and a gas seal gasket made of an electrically insulating material. This configuration has an internal gas distribution structure 127 for the inlet side and the outlet side of the fuel gas. Oxygen side gas delivery is based on an open channel structure. The construction includes end plates 170 for current collection and the unit cells 174, flow field plates 121 and gas seal structure 128 are arranged as a stack of cells 103 between the end plates 170.

An exemplary module configuration according to the present utility model includes battery stacks 103 arranged in a 2 x N matrix, N being any natural number. The configuration includes a fuel inlet manifold 150 and a fuel outlet manifold 152 between two adjacent cell stacks 103, the fuel inlet manifold 150 and the fuel outlet manifold 152 forming a fuel manifold 171 to deliver the supply fuel gas 108 to and from the stacks and the fuel exhaust 177. From the standpoint of fuel gas supply and fuel off-gas connection, the stacks are arranged in parallel connection in the manifold.

In yet another embodiment, the module configuration includes a pair of at least two cell stacks 103 electrically arranged in a series connection. In a further embodiment, the module configuration comprises X cell stacks 103 arranged in a series connection, wherein X is a natural number and satisfies 2N/x=y, where N and Y are natural numbers. The cell stack 103 is provided with a common oxygen side gas supply chamber 106, which is connected to the inlet side of the oxygen side gas transport open structure 105, and a common oxygen side exhaust gas chamber 176, which is connected to the outlet side of the oxygen side gas transport open structure 105. As shown in fig. 4 and 5, the fuel manifold 171 may have an inlet pipe connection 160 at a first end of the manifold and an outlet pipe connection 162 at a second end of the manifold. In another embodiment, the fuel manifold 171 may have an inlet pipe connection 160 at a first end of the manifold, an outlet pipe connection 162 at a second end of the manifold, and other arrangements are possible. The fuel manifold 171 includes size controllable airflow holes to the cell stack 103 for creating uniform airflow to and from the stack based on the pressure differential between the inlet and outlet tube connections 160, 162 of the fuel manifold 171. In a preferred embodiment, the module configuration includes means for controlling the size of each airflow aperture 133, 137 (fig. 6) for creating a uniform airflow between the cell stacks 103. The pressure loss may require a different pore size between the airflow apertures 133, 137.

As shown in fig. 7, the module arrangement further comprises a first gas seal 155, a first electrically insulating plate 119 and a second gas seal 156 between the fuel manifold 171 and the cell stack 103. On the top side 122 and the bottom side 124 of the cell stack 103, the module configuration includes a second electrically insulating plate 114, a compression structure 116 for the cell stack 103, and an airtight structure between the stacks. Each stacked end plate 170 is connected to an electrical connector 173. The module configuration may include a gas tight structure 200 in which the fuel manifold 171, the cell stack 103, the first and second gas seals 155, 156, and the first and second electrically insulating plates 119, 114 are positioned. The air side seal 169 has been sealed against the air-tight structure 200.

In an embodiment according to the utility model, the modular construction may comprise a compression structure 116 inside the airtight structure (fig. 7). In other embodiments according to the utility model, the modular construction may comprise a compression structure 116 external to the gas tight structure (fig. 8).

In a preferred embodiment, the modular construction may include centering structures in the top side 122 and the bottom side 124. The centering structure may include a threaded bore and a sealing portion. In a preferred embodiment, the modular arrangement may include a compensation plate on the top side 122 of the cell stacks 103 to compensate for height tolerances between the cell stacks 103. The modular construction may preferably include such an air flow structure in the fuel manifold 171 to create a pressure condition wherein the pressure loss in the fuel inlet manifold 150 and the fuel outlet manifold 152 is less than the pressure loss in the individual cells 174. The exemplary fuel manifold 171 shown in fig. 6 includes inlet and outlet tube connections 160, 162 to and from the stack of airflow holes 133, 137. In a preferred embodiment, the fuel inlet manifold 150 and the fuel outlet manifold 152 may be joined together by welding to increase structural rigidity and strength.

The fuel manifold 171 and the cover portion of the cell stack 103 are preferably made of materials having approximately the same coefficient of thermal expansion. The air side seal 169 preferably includes a hard ceramic in the middle portion and a soft ceramic in the edge portion. The fuel manifold 171 is preferably made of ferritic steel. The first electrically insulating plate 119 is preferably made of at least one dense material. The second electrically insulating plate 114 is preferably made of at least one of porous materials. The dense or porous material is preferably a ceramic material and/or a mineral. The gas seal structure 128 and the first and second gas seals 155, 156 are preferably manufactured by screen printing techniques and are made at least in part of a glass material, a glass ceramic material, or a braze alloy material. The module construction preferably includes ceramic and/or glass cement to bond the cells together with the first gas seal 155 and the second gas seal 156.

In one embodiment (e.g., fig. 2), the height of the flow holes may be determined by the distance from at least one of the bottom of the flow distribution region and the bottom of the flow outlet region to the bottom of the gasket structure to stabilize flow distribution in the stacked repeating structure with tolerance variations in electrolyte element structure thickness. Similar pressure loss conditions between cells are achieved by using a gasket structure that can be compressed and also pre-compressed at least from the flow portion in order to achieve a uniform heat distribution, i.e. a similar thermal gradient between cells in the stack. Therefore, the duty ratio of the solid oxide cell stack is increased, and also the lifetime of the stack becomes longer.

The cell stack configuration according to the present utility model may include a restricted aperture leading to the flow distribution region and leading to the flow outlet region. In one embodiment, the device may be used to direct a fuel feed stream from the side of the fuel cell to the flow distribution region. The gasket structure is compressed over the restricted orifice. The restrictive orifice ensures uniform distribution of fuel flow to the entire active area of the fuel cell electrode by creating an additional pressure drop across the flow path. The gasket structure also creates similar pressure loss conditions between the repeating structures of the fuel cell, which ensures uniform flow distribution characteristics for each repeating structure of the fuel cell. The uniform flow distribution in the fuel cell stack also ensures uniform heat distribution conditions of the fuel cell stack, i.e., similar thermal gradients between cells in the stack. Thus, the duty ratio of the fuel cell stack is increased, and the fuel cell stack life becomes longer.

The purpose of the gasket structure is also to ensure that the oxidant and fuel do not mix directly without fuel cell reaction inside the electrochemically active regions and that the fuel and oxidant do not leak from the electrochemical cells and that adjacent electrochemical cells do not electrically contact each other and that the oxidant and fuel are supplied to the desired flow field plate plane. The flow field plates are planar sheets made of metal alloys, ceramic materials, cermet materials, or other materials capable of withstanding the chemical, thermal, and mechanical stresses present in the fuel cell. The oxygen-enriched gas may be any gas or gas mixture that includes a measurable amount of oxygen.

Thus, while there have shown and described and pointed out fundamental novel features of the utility model as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated may be made by those skilled in the art without departing from the spirit of the utility model. For example, it is expressly intended that all combinations of those elements that perform substantially the same result are within the scope of the utility model. Substitutions of elements from one described embodiment to another are also fully intended and contemplated. It should also be understood that the drawings are not necessarily drawn to scale, but that they are merely conceptual in nature. Accordingly, it is intended that the scope of the appended claims be limited only.

Claims

1. A module configuration of solid oxide cell stacks in a fuel cell system or an electrolyser cell system, each solid oxide cell stack comprising a unit cell having a fuel side, an oxygen-rich side and an electrolyte material between the fuel side and the oxygen-rich side, each solid oxide cell stack comprising a flow field plate made of a material having a high electrical conductivity at high temperature, each solid oxide cell stack having four angled structures, each solid oxide cell stack comprising a gas seal structure made of an electrically insulating material, the module configuration of solid oxide cell stacks having an internal gas distribution structure for the inlet side and the outlet side of the fuel gas, the oxygen side gas transfer being based on an oxygen side gas transfer open structure, and the module configuration of the solid oxide cell stack comprises end plates for current collection and the unit cells, the flow field plates and the gas seal structure are arranged as a stack in the form of a solid oxide cell stack between the end plates, characterized in that the module configuration of the solid oxide cell stack is arranged in a 2 x N matrix, N being any natural number, and the module configuration of the solid oxide cell stack comprises a fuel inlet manifold and a fuel outlet manifold between two adjacent solid oxide cell stacks, which form a fuel manifold for delivering supplied fuel gas to and from the solid oxide cell stack and fuel off-gas from the point of view of fuel gas supply and fuel off-gas connection, the solid oxide cell stacks are arranged in parallel connection in the fuel manifold and the solid oxide cell stacks are arranged with a common oxygen side gas supply chamber and a common oxygen side exhaust gas chamber, the common oxygen side gas supply chamber being connected to an inlet side of an oxygen side gas transfer open structure, the common oxygen side exhaust gas chamber being connected to an outlet side of an oxygen side gas transfer open structure, and the fuel inlet manifold comprising gas flow holes of controllable size opening to the solid oxide cell stacks for forming a uniform gas flow to the solid oxide cell stacks and the fuel outlet manifold comprising gas flow holes of controllable size opening to the solid oxide cell stacks for forming a uniform gas flow from the solid oxide cell stacks, and the module configuration of the solid oxide cell stacks comprising a first gas seal, a first electrically insulating plate and a second gas seal between the fuel manifold and the solid oxide cell stacks and on a top side and a bottom side of the solid oxide cell stacks, the module configuration of the solid oxide cell stacks comprising a second electrically insulating plate, a compressed air end plate for connecting the solid oxide cell stacks to the solid oxide cell stacks each other and the solid oxide seal structure.

2. The solid oxide cell stacked module construction of claim 1, wherein the solid oxide cell stacked module construction includes means for controlling the size of each airflow aperture to create a uniform airflow between the solid oxide cell stacks.

3. The solid oxide cell stacked module configuration of claim 1, wherein the fuel manifold has an inlet pipe connection at a first end of the fuel manifold and an outlet pipe connection at a second end of the fuel manifold.

4. The solid oxide cell stacked module construction of claim 1, wherein the air side seal structure comprises a hard ceramic piece in a middle portion and a soft ceramic piece in an edge portion.

5. The solid oxide cell stack module construction of claim 1, wherein the cover portion of the solid oxide cell stack and the fuel manifold are made of materials having the same coefficient of thermal expansion.

6. The solid oxide cell stacked module construction of claim 1, wherein the first electrically insulating plate is made of a dense material.

7. The solid oxide cell stacked module construction of claim 1, wherein the second electrically insulating plate is made of a porous material.

8. The solid oxide cell stack module construction of claim 1, wherein the fuel manifold is made of ferritic steel.

9. The solid oxide cell stacked module configuration of claim 1, wherein the solid oxide cell stacked module configuration comprises a pair of at least two solid oxide cell stacks arranged electrically in series connection.

10. The solid oxide cell stacked module configuration of claim 1, comprising X solid oxide cell stacks arranged in a series connection, wherein X is a natural number and satisfies 2N/X = Y, wherein N and Y are natural numbers.

11. The solid oxide cell stack module configuration of claim 1, wherein the solid oxide cell stack module configuration comprises a compensation structure on a top side or a bottom side of the solid oxide cell stack for compensating for height tolerances between the solid oxide cell stacks.

12. The solid oxide cell stacked module construction of claim 1, wherein the solid oxide cell stacked module construction comprises a gas tight structure in which the fuel manifold, the solid oxide cell stack, the first and second gas seals, and the first and second electrically insulating plates are positioned and against which the air side seal structure is sealed.

13. The solid oxide cell stacked module construction of claim 12, wherein the solid oxide cell stacked module construction comprises the compression structure inside the hermetic structure.

14. The solid oxide cell stacked module construction of claim 12, wherein the solid oxide cell stacked module construction comprises the compression structure located outside of the hermetic structure.

15. The solid oxide cell stacked module construction of claim 1, comprising the fuel inlet manifold and the fuel outlet manifold connected together by welding to increase structural rigidity and strength.