Patent Application
20110086287
This application claims priority to Spanish Patent Application No. P200930826, filed Oct. 9, 2009.
This invention relates to solid oxide fuel stacks having at least one metal-supported tubular cell and at least one attached interconnector.
There are known in the state of the art, solid oxide fuel stacks comprising a plurality of tubular solid oxide fuel cells, which operate at high temperatures within an approximate range of 600 to 1000° C., and which, depending on the type of support used, may be categorized as tube-shaped solid oxide fuel cells with a cathode support, anode support, electrolyte support or metal support.
Tubular solid oxide fuel cells generally comprise a structure formed by an internal electrode, an electrolyte deposited on the internal electrode, an external electrode deposited on the electrolyte, and in the case of metal-supported tubular cells, a metal support deposited mainly on the external electrode.
One of the problems to be resolved in this type of fuel stacks is the difficulty of forming an electrical connection between the respective cells, given that this type of cell operates at high temperatures, and the interconnectors must be designed in such a way that they are sufficiently flexible to maintain proper electrical contact, and must also withstand large thermal cycles. The interconnectors must also have an optimum contact surface to prevent a reduction in the power density of the cells.
There are known different solutions, described for example in International Appl. No. WO2006/017777A2, U.S. Pat. No. 5,258,240 and U.S. Pat. No. 7,157,172, which describe fuel stacks that comprise anode and/or cathode-supported tubular cells in which each tubular cell comprises a built-in interconnector that comes into contact with the internal electrode. The electrical connection between the built-in interconnector in a tubular cell and the external electrode of another adjacent tubular cell is formed by individual nickel interconnectors positioned between the adjacent cells or by mesh or metal supports positioned between the tubular cells.
According to one implementation a solid oxide fuel stack is provided comprising: a first solid oxide fuel cell supported by and electrically coupled to a first connector, the first solid oxide fuel cell comprising a first electrode, an electrolyte deposited on the first electrode, a second electrode deposited on the electrolyte, and a first metal support arranged on the second electrode, the first connector having a first member in contact with a first portion of the first metal support, the first connector arranged to resiliently support the first solid oxide fuel cell by the application of contact pressure to the first portion of the first metal support.
According to one implementation a solid oxide fuel stack is provided comprising: first a solid oxide fuel cell supported between and electrically coupled to first and second connectors, the solid oxide fuel cell comprising a first electrode, an electrolyte deposited on the first electrode, a second electrode deposited on the electrolyte, and a first metal support arranged on the second electrode, the first connector having a first member in contact with a first portion of the first metal support and a second member in contact with a second portion of the first metal support, the second connector having a first member in contact with a third portion of the first metal support and a second member in contact with a fourth portion of the first metal support, the first and second connectors each arranged to resiliently support the first solid oxide fuel cell by the application of contact pressure to the first, second, third and fourth portions of the first metal support.
According to one implementation a solid oxide fuel stack is provided comprising: a solid oxide fuel cell supported between and electrically coupled to a first plate and a second plate by first and second connectors, respectively, the solid oxide fuel cell comprising a first electrode, an electrolyte deposited on the first electrode, a second electrode deposited on the electrolyte, and a metal support arranged on the second electrode, the first connector having a first member in contact with a first portion of the metal support and a second member in contact with a second portion of the metal support, the second connector having a first member in contact with a third portion of the metal support and a second member in contact with a fourth portion of the tubular support, the first and second connectors fixed to the first and second support plates, respectively, and each arranged to resiliently support the solid oxide fuel cell between the first and second support plates by the application of contact pressure to the first, second, third and fourth portions of the metal support.
According to one implementation a tubular solid oxide fuel cell is provided that comprises a first electrode, an electrolyte deposited on the first electrode, a second electrode deposited on the electrolyte, and a metal support arranged on the second electrode. In one implementation the interconnector comprises support means and contact means adapted for the electrical contact with the metal support, the contact means being arranged fixed to the support means and flexible in relation to said support means. The interconnector is also arranged preloaded in relation to the metal support, with the result that the contact pressure between the interconnector and the metal support is obtained by means of the preload, ensuring said contact even at high temperatures for long periods of time.
The flexibility of the contact means as opposed to the support means allows the interconnector to remain in contact with the metal support at all times regardless of the irregularities in shape that the tubular solid oxide fuel cell may present both longitudinally and transversally.
In addition, the interconnector has a compact and simple design that enables the fitting of the solid oxide fuel cell.
These and other advantages and characteristics of the invention will be made evident in the light of the drawings and the detailed description thereof.
Each tubular solid oxide fuel cell 1, shown in detail in
In the implementations of
In one implementation, each interconnector 6 comprises support means 7, which may include a substantially rectangular and rigid support plate 11, and contact means 8 through which the electrical contact of the interconnector 6 with the metal support 5 of the solid oxide fuel cell 1 is achieved. The contact means 8 is arranged fixed to the support plate 11 by welding or any other known means, and are flexible in relation to said support plate 11.
In some implementations the support plate 11 has a thickness of between approximately 0.5 and 1.0 mm, and may include, as shown in
In the implementations of
In addition, the corresponding interconnector 6 is arranged preloaded in relation to the metal support 5 with the aim of ensuring proper electrical contact at all times with the tubular fuel cell 1. To achieve this, in one implementation the solid oxide fuel stack 20 comprises preload means 15, shown in
In other embodiments not shown in the figures, the preload means 15 may include an external weight on at least one of the support plates 11 or preloaded springs arranged between the two support plates 11 of two interconnectors 6 facing each other, thereby ensuring the permanent contact between the corresponding interconnector 6 and the solid oxide fuel cell 1.
In addition, the contact means 8 comprise a contact plate 10,16 that includes at least one substantially flat fixing surface 10b,16b, through which the contact plate 10,16 is fixed to the support plate 11, and at least one contact surface 10c,16c flexible in relation to the fixing surface 10b,16b, adapting itself to the possible irregularities in shape that the tubular fuel cell 1 may present, either on its circular perimeter or longitudinally, thereby securing the permanent electrical contact of the interconnector 6 with the tubular fuel cell 1. In one implementation the contact means 8 also comprises connection surfaces 10d,16d that respectively connect each contact surface 10c,16c to the corresponding fixing surface 10b,16b.
According to some implementations each interconnector 6 comprises a plurality of contact plates 10,16 that have a thickness of between approximately 0.5 mm and 1 mm, and are arranged transversally along the metal support 5 and substantially parallel and equidistant to each other.
In the embodiments shown in
Additionally, in the embodiment shown in
In addition,
In other embodiments not shown in the figures, the contact plate 10,16 may have a single contact surface 10c,16c with the tubular fuel cell 1, said single contact surface 10c,16c being flexible in relation to the connection surface 10b,16b and therefore to the corresponding support plate 11.
According to some implementations, both the support plate 11 and the contact plate 10,16 are preferably made of a metal material capable of withstanding high temperatures, in excess of 800° C., for long periods of time. The oxidation behaviour of the material must be good at high temperatures, it must be able to resist creep when subjected to a constant force, and must also be easily conformable.
| Number | Date | Country | Kind |
|---|---|---|---|
| P200930826 | Oct 2009 | ES | national |
