DE102012221427A1 - Fuel cell system i.e. high temperature-fuel cell system, for use in e.g. vehicle, has fuel cells connected in series and/or parallel by interconnectors, where part of interconnectors is made from material with perovskite structure - Google Patents

Abstract

The system (10) has a fuel cell stack (11) comprising fuel cells (1, 2) connected in series and/or in parallel by interconnectors (3). A part of the interconnectors is made from material e.g. manganese, oxygen, scandium, lanthanum, strontium or lanthanum-strontium-scandium-manganese oxide, with perovskite structure. The cell stack is designed in the form of a sandwich-like function layer system comprising a cathode layer (K), an electrolyte layer (E) and an anode layer (A). Cathode areas (1a, 2a) are formed in the cathode layer, and anode areas (1b, 2b) are formed in the anode layer. The fuel cells are designed as high temperature-fuel cells. An independent claim is also included for a method for manufacturing a fuel cell system.

Description

The present invention relates to a fuel cell system, a lanthanum-strontium-scandium-manganese oxide, a fuel cell, a method for producing a fuel cell system or a fuel cell, their uses and a corresponding energy system.

State of the art

Solid oxide fuel cells (SOFCs) are used to generate electricity and possibly also heat and are often used in auxiliary power units or in combined heat and power plants (CHP) for domestic energy supply or industrial power supply and in power plants as well as on-board power generation Used vehicles. Since solid oxide fuel cells are conventionally operated at temperatures of 600 ° C to 1000 ° C, they are also referred to as high temperature fuel cells.

Fuel cells include a cathode, an anode, and an electrolyte disposed therebetween.

In order to realize a series connection (series connection) of fuel cells, a so-called interconnector can be used which connects the anode of one cell to the cathode of the next cell. The interconnector should be well electronically conductive but insulating against the ions participating in the reaction (H ⁺ in polymer electrolyte membrane cells (PEM), O ^2- in high temperature fuel cells (SOFC)).

In the high-temperature fuel cell (SOFC), the interconnector is usually formed of high-temperature-stable metal plates, for example chromium (Cr).

The publication EP 2 355 217 A1 describes a fuel cell system comprising an interconnector.

The publication EP 1 356 535 B1 describes an electrically conductive material based on a multiphase system of at least two phases, the major phase being a perovskite phase.

The pamphlets CN 101043079 A and CN 101599546 describe lanthanum, strontium, scandium, and manganese containing cathode materials for fuel cells.

Disclosure of the invention

The present invention is a fuel cell system, for example a high-temperature fuel cell system, which comprises a fuel cell stack consisting of series and / or parallel (single) fuel cells, which are connected in series and / or in parallel via interconnectors, wherein at least a part of the interconnectors, in particular the interconnectors, a material with perovskite structure (ABO ₃ ) contains. In particular, the at least one part of the interconnectors or the interconnectors may be formed from the material having a perovskite structure.

It has been found that materials with perovskite structure are particularly suitable as material for interconnectors for series and / or parallel switching of fuel cells in a fuel cell system. Materials having a perovskite structure can advantageously be processed well by powder technology, have sufficient electronic conductivity, for example of> 1 S / cm, and be of thermal expansion compatible with the other materials of the fuel cell system, which frequently likewise have a perovskite structure. which has an advantageous effect in particular during sintering. Thus, on the one hand during sintering compared to carrier and / or electrolyte materials, a, in particular mechanically, stable connection can be formed. On the other hand, this enables a common sintering, a so-called cosintering, of the materials of the fuel cell system. As a result, advantageously the process steps for producing the fuel cell system and thus the production costs for the fuel cell system can be reduced. In addition, materials with perovskite structure can be stable under cathode atmosphere. The fact that the interconnector material can be configured similarly to the other materials of the fuel cell system, it is also possible by suitable selection of materials, for example, occur during sintering, side reactions whose reaction products could block the flow of current, for example, with cathode materials and anode materials, or to avoid , For example, with electrolyte materials to effect targeted.

In the context of the present invention, a fuel cell stack can be understood to mean an arrangement, in particular substantially compact, of fuel cells (cathode-electrolyte-anode units), for example in which the fuel cells form a layer system, a package and / or a stack. The term fuel cell stack is therefore not to be construed as meaning that the fuel cells are stacked in the fuel cell stack have to. In particular, the fuel cells in the fuel cell stack may be arranged next to one another, wherein the fuel cell stack may be formed, for example, in the form of a layer system.

For example, the cathodes of the fuel cells may include or be formed of at least one cathode material selected from the group consisting of lanthanum strontium manganese oxide (LSM), lanthanum strontium scandium manganese oxide (LSSM), lanthanum strontium cobalt. Iron oxide (LSCF), lanthanum nickel iron oxide (LNF) and mixtures thereof. For example, the at least one cathode material may be selected from the group consisting of lanthanum strontium manganese oxide (LSM), lanthanum strontium scandium manganese oxide (LSSM), and mixtures thereof. Lanthanum strontium manganese oxide, lanthanum strontium scandium manganese oxide, lanthanum strontium cobalt iron oxide and lanthanum nickel iron oxide advantageously also have a perovskite structure.

In another embodiment, the cathodes of the fuel cells also comprise or are formed from a material having a perovskite structure. In particular, the material with perovskite structure of the interconnectors may be at least isostructural with the material having perovskite structure of the cathodes.

In the context of a further embodiment of this embodiment, the material with perovskite structure of the interconnectors comprises at least part of the chemical elements of the material with perovskite structure of the cathodes. In particular, the perovskite structure of the interconnects may comprise the chemical elements of the perovskite structure of the cathodes. In particular, the perovskite structure material of the interconnects may be formed of the same chemical elements as the perovskite structure of the cathodes. For example, the interconnects may be formed of the same material as the cathodes.

For example, the anodes of the fuel cells may comprise or be formed of at least one anode material selected from the group consisting of nickel and yttria stabilized zirconia cermets (Ni / YSZ), lanthanum strontium titanium oxide (Sr _1-1.5x La _x TiO ₃ ), lanthanum strontium scandium manganese oxide (LSSM) and mixtures thereof. In particular, anode material may include or be formed from lanthanum-strontium-titanium oxide and / or lanthanum-strontium-scandium-manganese oxide. Lanthanum strontium titanium oxide and lanthanum strontium scandium manganese oxide also advantageously have a perovskite structure.

Within the scope of a further embodiment, the anodes of the fuel cells therefore also comprise or are formed from a material having a perovskite structure. In particular, the material with perovskite structure of the interconnects may be at least isostructural with the material having the perovskite structure of the anodes.

In a further embodiment of this embodiment, the material with perovskite structure of the interconnectors comprises at least part of the chemical elements of the material with perovskite structure of the anodes. In particular, the perovskite-structured material of the interconnects may comprise the chemical elements of the perovskite-structured material of the anodes. For example, the perovskite structure material of the interconnects may be formed of the same chemical elements as the perovskite structure material of the anodes. Optionally, the interconnectors may be formed of the same material as the anodes.

It has proved to be advantageous if the material with perovskite structure of the interconnectors is manganese-containing or comprises manganese, in particular manganese oxide, or based thereon.

Cathode materials and anode materials, particularly cathode materials, for fuel cells may be based especially on manganese-containing materials. Because the manganese content of the interconnect material is also configured, side reactions which are based on a concentration balance of manganese can advantageously be avoided.

Since cathode materials and anode materials are often oxygen-containing or comprise oxygen, it may be advantageous if the material with perovskite structure of the interconnectors is oxygen-containing or comprises or is based on oxygen.

Within the scope of a further embodiment, therefore, the material with perovskite structure of the interconnectors and / or the cathodes and / or the anodes, for example the interconnectors and the cathodes, in particular the interconnectors, contains manganese and / or oxygen, in particular containing manganese and oxygen, or comprises the material with perovskite structure of the interconnectors and / or the cathodes and / or the anodes, for example the interconnectors and the cathodes, in particular the interconnectors, manganese and / or oxygen, in particular manganese and oxygen, for example manganese oxide, or based thereon.

Scandium can advantageously improve the chemical stability of the material in a reducing environment. Thus, advantageously, the stability of the material in the anode atmosphere can be increased.

Within the scope of a further embodiment, therefore, the material with perovskite structure of the interconnectors and / or the cathodes and / or the anodes, in particular the interconnectors and the cathodes, in particular the interconnectors, comprises scandium or contains scandium.

By scandium, in particular, the chemical stability of, for example, manganese oxide based or comprehensive materials with perovskite structure can be improved in a reducing environment.

In particular, the material with perovskite structure of the interconnectors and / or the cathodes and / or the anodes, for example the interconnectors and the cathodes, in particular the interconnectors, therefore, a scandium and manganese and oxygen comprising material with perovskite structure, for example a material with Perovskite structure, which is based on a scandium manganese oxide, be. In particular, the B sites of the perovskite structure may comprise manganese and scandium, in particular being occupied by manganese and scandium.

Within the scope of a further embodiment, the material with perovskite structure comprises the interconnectors and / or the cathodes and / or the anodes, for example the interconnectors and the cathodes, in particular the interconnectors, lanthanum. In particular, the A sites of the perovskite structure may comprise lanthanum, in particular be occupied by lanthanum.

Within the scope of a further embodiment, the material with perovskite structure of the interconnectors and / or the cathodes and / or the anodes, for example the interconnectors and the cathodes, in particular the interconnectors, comprises at least one alkaline earth metal, in particular strontium. In particular, the A sites of the perovskite structure may comprise at least one alkaline earth metal, in particular strontium, in particular with the at least one alkaline earth metal, in particular strontium.

In this case, lanthanum and the at least one alkaline earth metal, for example strontium, in particular occupy the A sites of the perovskite structure.

In a further embodiment, the material with perovskite structure of the interconnectors and / or the cathodes and / or the anodes, in particular the interconnectors, is a lanthanum-strontium-scandium-manganese oxide (LSSM), for example (La, Sr) (Mn, Sc) O ₃ .

Lanthanum-strontium-scandium-manganese oxides (LSSM) with perovskite structure, for example (La, Sr) (Mn, Sc) O ₃ , can advantageously have sufficient electronic conductivity in cathodic (30 S / cm at 800 ° C) and anodic ( 5 S / cm at 850 ° C) and advantageously be thermally-expandable compatible with the other materials in the fuel cell system. Lanthanum-strontium-scandium-manganese oxides (LSSM) can also be used as cathode material and anode material, in particular as cathode material, and are isostructural with lanthanum-strontium-manganese oxides (LSM), for example (La, Sr) MnO ₃ , which are also used as cathode materials and anode materials, in particular as cathode materials, can be used, which is why when using lanthanum-strontium-scandium-manganese oxides (LSSM) as interconnector material and lanthanum-strontium-scandium-manganese oxides (LSSM) or lanthanum-strontium-manganese oxides (LSM) as Cathode material or anode material, a formation of new phases can be avoided at the interface. In addition, lanthanum-strontium-scandium-manganese oxides (LSSM) can advantageously be processed well by powder technology, for example by screen printing.

In a further embodiment, the perovskite structure material of the interconnects is (La ₁ -x Sr _x ) _a Sc _y Mn _{1 -y} O _{3 -δ} , where 0.1≤x≤0.3, 0.05≤y ≤ 0.2 and 0.95 ≤ a ≤ 1. Here, in particular, depends on the ratio between Mn ³⁺ and Mn ⁴⁺ . For example, -0.3 ≦ δ ≦ 0.3, for example -0.2 ≦ lanthanum-strontium-scandium-manganese oxides of this composition have been found to be particularly advantageous as an interconnector material. The interconnect material may be, for example, a single-phase material.

In another embodiment, the cathode material is or is the perovskite structure of the cathodes (La _1-x Sr _x ) _a Sc _y Mn _1-y O _{3 -δ} , where 0.1 ≦ x ≦ 0.3, 0.05 ≤ y ≤ 0.2 and 0.95 ≤ a ≤ 1. Here, depending in particular on the relationship between Mn ³⁺ and Mn ⁴⁺ . For example, -0.3 ≦ δ ≦ 0.3, for example -0.2 ≦ δ ≦ 0.2. Lanthanum-strontium-scandium-manganese oxides of this composition have a perovskite structure and have also proved to be particularly advantageous as a cathode material. The cathode material may be, for example, a single-phase material.

In the context of a further embodiment, the material is or is the material perovskite structure of the anodes (La _1-x Sr _x ) _a Sc _y Mn _1-y O _{3 -δ} , where 0.1 ≦ x ≦ 0.3, 0.05 ≤ y ≤ 0.2 and 0.95 ≤ a ≤ 1. Here, depending in particular on the relationship between Mn ³⁺ and Mn ⁴⁺ . For example, -0.3 ≦ δ ≦ 0.3, for example -0.2 ≦ δ ≦ 0.2, lanthanum-strontium-scandium-manganese oxides of this composition have a perovskite structure and have also been found to be particularly advantageous as an anode material proved. The anode material may be, for example, a single-phase material.

For example, the electrolytes of the fuel cells may include or be formed of at least one electrolyte material selected from the group consisting of yttria-stabilized zirconia (YSZ), scandium-stabilized zirconia (ScSZ), and mixtures thereof. If appropriate, the electrolyte material may contain lanthanum and strontium in an interface, in particular for the interconnector material.

In the context of a further embodiment, the fuel cell stack is designed in the form of a sandwich-type functional layer system which comprises a cathode layer, an electrolyte layer and an anode layer.

In this case, cathode regions can be formed in the cathode layer which form the cathodes of the fuel cells. In this case, the cathode regions can be separated, for example, by electrically and ionically insulating regions (from one another).

Anode regions may be formed in the anode layer which form the anodes of the fuel cells. In this case, the anode regions can be separated, for example, by electrically and ionically insulating regions (from one another).

In the electrolyte layer, electrolyte regions may be formed which form the electrolytes of the fuel cells.

Furthermore, interconnector regions, which form the interconnectors via which the fuel cells are connected in series and / or in parallel, can be formed in the electrolyte layer. For example, a cathode region of a fuel cell can be connected in series with an anode region of another fuel cell via an interconnector region, and / or a cathode region of a fuel cell can be connected in parallel with a cathode region of another fuel cell. The electrolyte regions may be at least partially separated from one another by interconnector regions, in particular ionically insulating.

In a further embodiment, at least one cathode region of a fuel cell arranged in the cathode layer and an anode region of another fuel cell arranged in the anode layer are arranged partially overlapping. In particular, an interconnector region may be formed in the electrolyte layer in the overlapping region. Thus, advantageously, a particularly compact fuel cell stack can be realized with the largest possible electrochemically active surfaces.

In the context of a further embodiment, the fuel cell system has a carrier body. By the carrier body of the fuel cell stack or the functional layer system can be mechanically relieved, so that the fuel cells can be made thinner. In particular, a reduction of the electrolyte layer thickness has an advantageous effect on the conductivity of the electrolyte and thus the performance of the fuel cell.

In particular, the carrier body can be designed tubular. For example, the raw carrier body can be configured closed on one side. For example, the carrier body can have at least one open tube end a fastening section for fastening the carrier body to a carrier substrate. At the other end of the tube, the carrier body can either likewise have such a fastening section or, in particular, be closed by a cap section. The two attachment portions or the attachment portion and the cap portion may be configured in particular gas-tight. In the section (s) adjacent to the fuel cells, the carrier body is preferably gas-permeable and has, for example, gas-permeable pores and / or openings.

In the porous section (s), the support body can have, for example, an open porosity of ≥ 20%, for example of ≥ 25% or of ≥ 30% or of ≥ 40%, for example of about 40%.

The pores can have an average pore size of ≦ 300 μm, for example ≦ 200 μm or ≦ 100 μm or ≦ 50 μm, and, for example, a percolating pore network with a through-distribution in a range of ≥ 1 μm to ≦ 20 μm, in particular 1 μm to ≤ 10 μm, for example of about 5 μm. Such a pore penetration distribution advantageously allows free gas diffusion, in particular without the occurrence of a so-called Knudsen effect.

The carrier body may in particular be formed from an inert material. In this case, inert can be understood as meaning that the material does not serve as an electrode or electrolyte. In this case, the fuel cell system may be referred to, for example, as an inertly supported fuel cell system.

The carrier body can be formed, for example, from one or more ceramic and / or glassy materials. For example, the carrier body may comprise or be formed of at least one material selected from the group consisting of magnesium silicates, in particular forsterite, zirconium dioxide, in particular doped zirconium dioxide, for example with 6.5% by weight or more of yttrium oxide (Y ₂ O ₃ ) doped zirconia, alumina, alumina-zirconia mixtures, spinels, for example, magnesium aluminate, zirconia-glass mixtures, zinc oxide, and mixtures thereof.

In particular, the carrier body may comprise or be formed from at least one magnesium silicate, in particular forsterite. Forsterite is based essentially on the general empirical formula Mg ₂ SiO ₄ . Forsterite can advantageously be highly electrically insulating and ionic and, for example, have a specific electrical resistance of 10 ¹¹ Ωm at 20 ° C. and a specific electrical resistance of 10 ⁵ Ωm at 600 ° C. Thus, it is advantageously possible to avoid electrical and ionic short circuits and to dispense with one or more additional insulation layers. Further advantages of Forsterit are its sintering behavior and its thermal expansion coefficient. Thus, forsterite can have advantageous shrinkage properties and an advantageous shrinkage kinetics. The thermal expansion coefficient of Forsterit can also substantially correspond to the thermal expansion coefficient of the materials of the fuel cell stack or functional layer system and be about 10 to 11 · 10 ^-6 K ^-1 , which is advantageous to a simultaneous sintering (cosintering) of the carrier body and the interconnectors, in particular of the fuel cell stack or the functional layer system. In addition, forsterite can be obtained via a reaction sintering from inexpensive raw materials, such as talc and magnesium oxide, which further contributes to cost savings in the production.

It is also possible that the support body also comprises or is formed from a material having a perovskite structure. For example, the material with perovskite structure of the interconnectors can be at least isostructural with the material with perovskite structure of the carrier body.

In principle, it is possible for the cathodes of the fuel cells or the cathode layer of the functional layer system as well as the anodes of the fuel cells or the anode layer of the functional layer system to be adjacent to the carrier body.

In the context of a further embodiment, however, the cathodes of the fuel cells or the cathode layer of the functional layer system adjoin the carrier body. The anodes can be open or freely accessible. This offers the possibility of using base metals and their alloys, for example nickel or nickel alloys, as anode material and / or as material for electrically contacting the fuel cells connected in series and / or in parallel via interconnectors, thereby further reducing the material and manufacturing costs.

The fuel cell stack can be applied, for example in the form of the functional layer system, for example on the inside or on the outside, in particular on the inside, of the, for example, raw, carrier body.

Within the scope of another embodiment, interconnectors, in particular the (complete) functional layer system, are produced by screen printing. Thus, advantageously, thin electrolytes can be realized, which advantageously affects the conductivity of the electrolyte and thus the performance of the fuel cell.

In a further embodiment, the materials of the functional layer system and optionally the carrier body are co-sintered, that is to say sintered simultaneously. As already explained, the production costs can advantageously be reduced in this way.

Advantageously, it is altogether possible to make available a fuel cell system in which fuel cells are connected in series and / or in parallel by interconnectors which are formed from a material which can be powder-processed, is stable in the anode and cathode atmosphere, a good one has electronic conductivity, for example, of> 1 S / cm, and when sintering forms no current flow blocking reaction products with cathode and anode materials.

Insofar as this is desired, the interconnector material can be designed such that it is also stable to carrier and electrolyte materials during sintering.

However, it is also possible to design the interconnector material such that it forms current-blocking reaction products with the carrier and electrolyte materials during sintering, in particular in order to suppress a parasitic current flow in this way.

With regard to further technical features and advantages of the fuel cell system according to the invention, reference is hereby explicitly made to the explanations in connection with the lanthanum strontium scandium manganese oxide according to the invention, the fuel cell according to the invention, the method according to the invention, the uses according to the invention, the energy system according to the invention and with the figure.

A further subject of the present invention is a lanthanum-strontium-scandium-manganese oxide, in particular having a perovskite structure, the general chemical formula: (La _1-x Sr _x ) _a Sc _y Mn _1-y O _{3 -δ} , in which
0.1 ≤ x ≤ 0.3
0.05 ≤ y ≤ 0.2 and
0.95 ≦ a ≦ 1.2, especially 1 ≦ a ≦ 1.2 and 1 <a ≦ 1.2, or 0.95 ≦ a ≦ 1 and 0.95 ≦ a <1, respectively.

In particular, it depends on the ratio between Mn ³⁺ and Mn ⁴⁺ . For example, -0.3 ≦ δ ≦ 0.3, for example, -0.2 ≦ δ ≦ 0.2. Lanthanum-strontium-scandium-manganese oxides with a> 1 are unstable under sintering conditions and can transform under sintering conditions into lanthanum-strontium-scandium-manganese oxides with a = 1. Lanthanum oxide (La ₂ O ₃ ) and strontium oxide (SrO) can form as secondary phases. In contact with zirconia, for example, yttria-stabilized zirconia (Y-ZrO ₂ ) and / or scandium-stabilized zirconia (ScSZ), which is often used as the electrolyte material, lanthanum zirconia (La ₂ Zr ₂ O ₇ ) and strontium zirconia (SrZrO ₃ ) may be formed. As a result, an electrically insulating interface can form between the lanthanum-strontium-scandium-manganese oxides and the zirconium oxide, for example the electrolyte. Insofar as the lanthanum-strontium-scandium-manganese oxide is used as interconnector material, this is advantageous since the interconnector material is not intended to ensure an electrical connection between the cathode material and the anode material but to the electrolyte material. After sintering in contact with zirconia, the interconnect material may have a composition of a = 1.

For a ≦ 1, in particular a <1, the reaction with zirconium oxide, for example yttrium-stabilized zirconium dioxide (Y-ZrO ₂ ) and / or scandium-stabilized zirconium dioxide (ScSZ), and thus the formation of an electrically insulating interface is suppressed. This is particularly desirable for the use of the lanthanum-strontium-scandium-manganese oxide as the cathode material and / or anode material, in particular cathode material, since otherwise no current could flow into the electrolyte.

By 0.1.ltoreq.x.ltoreq.0.3, it is advantageously possible to obtain a material which can be used both as interconnector material as cathode material and / or anode material. In addition, by such a strontium advantageously an interdiffusion of strontium between the lanthanum strontium scandium manganese oxide according to the invention and, for example, used as a cathode material or anode material, lanthanum-strontium manganese oxide with similar strontium, for example, x ≈ 0.2, as far as possible be prevented.

By 0.05 ≤ y ≤ 0.2, on the one hand, the perovskite structure can be stabilized at low partial pressures. On the other hand, by 0.05 ≦ y ≦ 0.2, the chemical stability of the material in a reducing environment can be sufficiently increased in order to also allow use of the material in anodes atmosphere, for example as interconnector material and / or anode material. Advantageously, in addition, the material costs can be kept low.

Lanthanum-strontium-scandium-manganese oxides with 1 ≦ a ≦ 1.2, or 1 <a ≦ 1.2 have proven to be advantageous, in particular as interconnector material, for the production of interconnectors, in particular wherein 0.95 ≦ a ≦ after sintering 1 can be.

Such lanthanum-strontium-scandium-manganese oxides with 0.95 ≦ a ≦ 1 or 0.95 ≦ a <1 have proven to be advantageous for the production of cathodes and / or anodes, in particular as cathode material and / or anode material, in particular sintering can remain 0.95 ≤ a ≤ 1.

With regard to further technical features and advantages of the lanthanum-strontium-scandium manganese oxide according to the invention, reference is hereby explicitly made to the explanations in connection with the fuel cell system according to the invention, the fuel cell according to the invention, the method according to the invention, the uses according to the invention, the energy system according to the invention and with the figure.

A further subject matter of the present invention is a fuel cell comprising at least one lanthanum-strontium-scandium-manganese oxide according to the invention, where 0.95 ≤ a ≤ 1 or 0.95 ≤ a <1. For example, the cathode of the fuel cell and / or the anode of the fuel cell and / or an electrical interconnection element, for example an interconnector, the fuel cell may comprise or be formed from the at least one lanthanum-strontium-scandium-manganese oxide. In particular, an electrical interconnection element, for example an interconnector, of the fuel cell may comprise or be formed from the at least one lanthanum-strontium-scandium-manganese oxide.

With regard to further technical features and advantages of the fuel cell according to the invention, reference is hereby explicitly made to the explanations in connection with the fuel cell system according to the invention, the lanthanum strontium scandium manganese oxide according to the invention, the method according to the invention, the uses according to the invention, the energy system according to the invention and with the figure.

Another object of the present invention is a method, in particular for the production of a fuel cell system according to the invention or a fuel cell according to the invention.

In the method, in particular at least one interconnector of the fuel cell system can be produced by screen printing. For example, the interconnectors can be produced by screen printing. In particular, the (complete) functional layer system can be produced by screen printing.

In particular, at least one interconnector of the fuel cell system may contain a material having a perovskite structure.

The material having a perovskite structure may, for example, be a lanthanum-strontium-scandium-manganese oxide, for example a lanthanum-strontium-scandium-manganese oxide according to the invention. In this case, the at least one interconnector can be formed, for example, from a lanthanum-strontium-scandium-manganese oxide, in particular a lanthanum-strontium-scandium-manganese oxide according to the invention, with 1 ≦ a ≦ 1.2, for example by screen printing, in particular adjacent to a zirconium oxide-based material become. By means of sintering, an electrically insulating interface between the zirconia-based material and the lanthanum-strontium-scandium-manganese oxide can be formed, in particular wherein a ≦ 1 or a = 1 can be after sintering.

Preferably, in the method, the materials of the functional layer system and optionally the carrier body are co-sintered.

With regard to further technical features and advantages of the method according to the invention, reference is hereby explicitly made to the explanations in connection with the fuel cell system according to the invention, the lanthanum strontium scandium manganese oxide according to the invention, the fuel cell according to the invention, the uses of the invention, the energy system according to the invention and with the figure.

A further subject matter of the present invention is the use of a lanthanum-strontium-scandium-manganese oxide according to the invention as interconnector material and / or as cathode material and / or as anode material and / or for producing an interconnector of a fuel cell and / or for producing a cathode of a fuel cell and / or or for producing an anode of a fuel cell and / or for producing an electrically insulating interface, in particular for a zirconium oxide-based material, in particular a fuel cell, and / or for producing a fuel cell.

In particular, 1 ≦ a ≦ 1.2 or 1 <a ≦ 1.2 may be used for producing an interconnector and / or for producing an electrically insulating interface. Advantageously, it can thereby be effected that the lanthanum-strontium-scandium-manganese oxide reacts with the zirconium oxide-based material or an electrolyte to form an electrically insulating interface.

In the, in particular sintered, interconnector material and / or in the, in particular unsintered and sintered, cathode material and / or in the, in particular unsintered and sintered, anode material and / or for producing a cathode and / or for producing an anode can in particular 0.95 ≤ a ≤ 1 or 0.95 ≤ a <1, respectively.

Another object of the present invention is the use of a fuel cell system according to the invention and / or a fuel cell according to the invention and / or a fuel cell system according to the invention and / or a fuel cell produced according to the invention as a high temperature fuel cell / s.

With regard to further technical features and advantages of the uses according to the invention, reference is hereby explicitly made to the explanations in connection with the fuel cell system according to the invention, the lanthanum strontium scandium manganese oxide according to the invention, the fuel cell according to the invention, the method according to the invention, the energy system according to the invention and with the figure.

Furthermore, the present invention relates to an energy system, for example a combined heat and power plant, for example for a residential or commercial building, an industrial plant, a power plant or a vehicle, for example a micro-cogeneration plant, and / or a vehicle which comprises / s a fuel cell system according to the invention and / or a fuel cell system produced according to the invention and / or a fuel cell according to the invention and / or a fuel cell produced according to the invention and / or used. A (micro) combined heat and power plant may, in particular, be understood to mean a plant for the simultaneous generation of electricity and heat from an energy source.

With regard to further technical features and advantages of the energy system according to the invention, reference is hereby explicitly made to the explanations in connection with the fuel cell system according to the invention, the lanthanum strontium scandium manganese oxide according to the invention, the fuel cell according to the invention, the method according to the invention, the uses according to the invention and with the figure.

drawing

Further advantages and advantageous embodiments of the objects according to the invention are illustrated by the drawing and explained in the following description. It should be noted that the drawing has only descriptive character and is not intended to limit the invention in any way. It shows

1 a schematic cross section through an embodiment of a fuel cell system according to the invention.

1 shows that the fuel cell system 10 , a fuel cell stack 11 from series-connected fuel cells 1 . 2 includes, which via interconnectors 3 are connected in series.

1 illustrates that the fuel cell stack 11 is formed in the form of a multilayer, sandwich-type layer system, wherein the fuel cells 1 . 2 are formed substantially side by side. 1 shows that the functional layer system 11 wherein a cathode layer K, an electrolyte layer E and an anode layer A comprises, wherein in the cathode layer K cathode regions 1a . 2a are formed, which are the cathodes of the fuel cell 1 . 2 form, wherein in the anode layer A anode regions 1b . 2 B are formed, which are the anodes of the fuel cell 1 . 2 form and wherein in the electrolyte layer E electrolyte areas 1c . 2c are formed, which are the electrolytes of the fuel cell 1 . 2 form.

1 shows that in the electrolyte layer E also at least one interconnector area 3 is formed, which is an interconnector 3 forms over which the fuel cells 1 . 2 are connected in series. In particular, it is via the interconnector or interconnector area 3 the cathode area 1a the one fuel cell 1 with the anode area 2 B the other fuel cell 2 connected in series.

1 illustrates that while doing the electrolyte areas 1c . 2c at least in the area shown in the cross section shown through the interconnector area 3 , in particular ionically insulating, are separated from one another. Before and behind the plane of the paper, the electrolyte areas can be separated from each other by other ionically insulating areas.

1 further illustrates that the cathode regions 1a . 2a by at least one electrically and ionically insulating region 4 and the anode areas 1b . 2 B by at least one electrically and ionically insulating region 5 are separated from each other.

In the in 1 In addition, the cathode regions are shown 1a . 2a and anode areas 1b . 2 B formed in the cathode layer K or anode layer A such that the cathode region 1a the one fuel cell 1 the anode area 2 B the other fuel cell 2 partially overlapped. In the overlapping region, the interconnector region is present in the electrolyte layer E. 3 educated.

1 further shows that the fuel cell system 10 a carrier body 12 having. The tubular carrier body 12 For example, it may be formed of one or more ceramic and / or vitreous materials. Basically, it may be in the carrier body 12 to act both a tubular or tubular carrier body and a planar carrier body. The fuel cell system 10 Therefore, it can be both a tubular fuel cell system and a planar fuel cell system. In particular, the fuel cell system may be a tubular fuel cell system. Of the Fuel cell stack 11 can in this case on the inside or on the outside, in particular on the inside, of the carrier body 12 be upset.

1 illustrates that while the cathodes 1a . 2a the fuel cells 1 . 2 or the cathode layer K of the functional layer system 11 to the carrier body 12 adjoin. The anodes 1b . 2 B the fuel cells 1 . 2 or the anode layer A of the functional layer system 11 is open or freely accessible.

The puncturing of the carrier body 12 indicates that the carrier body 12 in that to the fuel cells 1 . 2 adjacent section has gas permeable pores and / or openings.

According to the invention contains the interconnector 3 a material with perovskite structure (ABO ₃ ). For example, the interconnector 3 a lanthanum-strontium-scandium-manganese oxide (LSSM) (La, Sr) (Mn, Sc) O ₃ having perovskite structure.

(La, Sr) (Mn, Sc) O ₃ (LSSM) with perovskite structure advantageously has sufficient electronic conductivity in cathodic (30 S / cm at 800 ° C) and anodic (5 S / cm at 850 ° C) atmosphere , It is advantageously compatible in thermal expansion with the other materials in the (high temperature) fuel cell system ((SO) FC). LSSM can also be used as a cathode material and is isostructural with the cathode material lanthanum-strontium-manganese oxide (LSM) ((La, Sr) MnO ₃ ), which is why when using LSSM as interconnector material and LSSM or LSM as the cathode material advantageously no new phases form at the interface. In the case of using LSSM as interconnector material and LSM as cathode material, although only a slight concentration balance of scandium (Sc) can occur, which is essentially harmless. By using LSSM as interconnector and cathode material, it is also possible to avoid scandium concentration compensation. Although LSSM can react to form lanthanum zirconate (La ₂ Zr ₂ O ₇ ) at the interface with an electrolyte formed from zirconium dioxide (ZrO ₂ ), the resulting reaction layer is only very thin, for example <100 nm thick, and also beyond this interface no current must flow, harmless to the function. Advantageously, the powder processing properties of LSSM are also very similar to those of LSM.

The doping with scandium (Sc) advantageously stabilizes the lanthanum-strontium-manganese oxide (LSM) which is unstable in reducing environment, which is why lanthanum-strontium-scandium-manganese oxide (LSSM) is advantageously also suitable for use in anodes atmosphere. Preferably, lanthanum-strontium-scandium-manganese oxide (LSSM) of the composition (La _1-x Sr _x ) _a Mn ₁ -y Sc _y O _{3 -δ} with x = 0.1 ... 0.3, y = 0, 05 ... 0.2 and a = 0.95 ... 1 are used. The lanthanum-strontium-scandium-manganese oxide (LSSM) can advantageously be processed as a powder into a screen-printing paste and, together with the other components, used to produce the electrode-electrolyte functional-layer package and then to sinter it.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 2355217 A1 [0006]
• EP 1356535 B1 [0007]
• CN 101043079 A [0008]
• CN 101599546 [0008]

Claims (15)

Fuel cell system ( 10 ) comprising a fuel cell stack ( 11 ) of fuel cells connected in series and / or in parallel ( 1 . 2 ), wherein the fuel cells ( 1 . 2 ) via interconnectors ( 3 ) are connected in series and / or in parallel, characterized in that at least a part of the interconnectors ( 3 ) contains a material with perovskite structure. Fuel cell system ( 10 ) according to claim 1, characterized in that the cathodes ( 1a . 2a ) and / or anodes ( 1b . 2 B ) of the fuel cells ( 1 . 2 ) also comprise a material with perovskite structure, in particular wherein the material with perovskite structure of the interconnectors ( 3 ) at least a portion of the chemical elements of the perovskite structure of the cathodes ( 1a . 2a ) and / or anodes ( 1b . 2 B ). Fuel cell system ( 10 ) according to claim 1 or 2, characterized in that the material with perovskite structure of the interconnectors ( 3 ) and / or the cathode ( 1a . 2a ) and / or the anodes ( 1b . 2 B ) Comprises manganese and / or oxygen. Fuel cell system ( 10 ) according to one of claims 1 to 3, characterized in that the material with perovskite structure of the interconnectors ( 3 ) and / or the cathode ( 1a . 2a ) and / or the anodes ( 1b . 2 B ) Scandium includes. Fuel cell system ( 10 ) according to one of claims 1 to 4, characterized in that the material with perovskite structure of the interconnectors ( 3 ) and / or the cathode ( 1a . 2a ) and / or the anodes ( 1b . 2 B ) Lanthanum includes. Fuel cell system ( 10 ) according to one of claims 1 to 5, characterized in that the material with perovskite structure of the interconnectors ( 3 ) and / or the cathode ( 1a . 2a ) and / or the anodes ( 1b . 2 B ) comprises at least one alkaline earth metal, in particular strontium. Fuel cell system ( 10 ) according to one of claims 1 to 6, characterized in that the material with perovskite structure of the interconnectors ( 3 ) a lanthanum-strontium-scandium-manganese oxide, in particular (La _1-x Sr _x ) _a Sc _y Mn _{1 -y} O _{3 -δ} , where 0.1 ≦ x ≦ 0.3, 0.05 ≦ y ≦ 0, 2 and 0.95 ≤ a ≤ 1, and / or wherein the perovskite structure material of the cathodes ( 1a . 2a ) Lanthanum-strontium-manganese oxide and / or lanthanum-strontium-scandium-manganese oxide, in particular (La _1-x Sr _x ) _a Sc _y Mn _{1 -y} O _{3 -δ} , where 0.1 ≦ x ≦ 0.3, 0 , 05 ≤ y ≤ 0.2 and 0.95 ≤ a ≤ 1, and / or wherein the perovskite structure material of the anodes ( 1b . 2 B ) Lanthanum-strontium-scandium-manganese oxide, in particular (La _1-x Sr _x ) _a Sc _y Mn ₁ -y O ₃ -δ, where 0.1 ≦ x ≦ 0.3, 0.05 ≦ y ≦ 0.2 and 0.95 ≤ a ≤ 1. Fuel cell system ( 10 ) according to one of claims 1 to 7, characterized in that the fuel cell stack ( 11 ) in the form of a sandwich-type functional layer system which comprises a cathode layer (K), an electrolyte layer (E) and an anode layer (A), wherein cathode regions (K) in the cathode layer (K) 1a . 2a ) are formed, which the cathodes of the fuel cell ( 1 . 2 ), wherein in the anode layer (A) anode regions ( 1b . 2 B ) are formed, which the anodes of the fuel cells ( 1 . 2 ), wherein in the electrolyte layer (E) electrolyte regions ( 1c . 2c ) are formed, which the electrolyte of the fuel cell ( 1 . 2 ), and wherein in the electrolyte layer (E) further interconnector areas ( 3 ) are formed, which the interconnectors ( 3 ), over which the fuel cells ( 1 . 2 ) are connected in series and / or in parallel, in particular wherein at least one cathode region (K) arranged in the cathode region ( 1a ) a fuel cell ( 1 ) and an anode region (A) disposed in the anode layer (A) ( 2 B ) of another fuel cell ( 2 ) are arranged partially overlapping, in particular wherein in the overlapping region an interconnector region ( 3 ) is formed in the electrolyte layer (E). Fuel cell system ( 10 ) according to one of claims 1 to 8, characterized in that the fuel cell system ( 10 ) a, in particular tubular, carrier body ( 12 ), in particular wherein the cathodes ( 1a . 1b ) of the fuel cell or the cathode layer (K) of the functional layer system ( 11 ) to the carrier body ( 12 ). Lanthanum-strontium-scandium-manganese oxide, especially with perovskite structure, the general chemical formula: (La _1-x Sr _x ) _a Sc _y Mn _1-y O _{3 -δ} , wherein 0.1 ≦ x ≦ 0.3, 0.05 ≦ y ≦ 0.2 and 0.95 ≦ a ≦ 1.2, more preferably 1 <a ≦ 1.2 or 0.95 ≦ a ≦ 1. A fuel cell comprising at least one lanthanum-strontium-scandium-manganese oxide according to claim 10, wherein 0.95 ≤ a ≤ 1. Method for producing a fuel cell system ( 10 ) according to one of claims 1 to 8 or a fuel cell according to claim 11, characterized in that at least one interconnector ( 3 ) of the fuel cell system ( 10 ), in particular the functional layer system ( 11 ), by screen printing produced and / or the materials of the functional layer system ( 11 ) and optionally the carrier body ( 12 ) are co-sintered; and / or at least one interconnector ( 3 ) of the fuel cell system ( 10 ) contains a material having a perovskite structure, in particular wherein the at least one interconnector ( 3 ) is formed from a lanthanum-strontium-scandium-manganese oxide according to claim 10 with 1 <a ≤ 1.2 adjacent to a zirconia-based material, wherein by sintering an electrically insulating interface between the zirconia-based material and the lanthanum-strontium-scandium Manganese oxide is formed, in particular wherein after sintering a ≤ 1. Use of a lanthanum-strontium-scandium-manganese oxide according to claim 10 as interconnector material and / or as cathode material and / or as anode material and / or for producing an interconnector of a fuel cell and / or for producing a cathode of a fuel cell and / or for producing an anode of a Fuel cell and / or for producing an electrically insulating interface, in particular to a zirconia-based material, in particular a fuel cell, and / or for producing a fuel cell, in particular wherein for producing an interconnector and / or for producing an electrically insulating interface 1 <a ≤ Is 1.2, and / or wherein in the interconnector material and / or in the cathode material and / or in the anode material and / or for producing a cathode and / or for producing an anode 0.95 ≤ a ≤ 1. Use of a fuel cell system ( 10 ) according to one of claims 1 to 9 and / or a fuel cell according to claim 11 and / or a fuel cell system produced by a method according to claim 12 ( 10 ) and / or a fuel cell manufactured by a method according to claim 12 as a high-temperature fuel cell / s. Energy system, in particular for a residential or commercial building, an industrial plant, a power plant or a vehicle, comprising a fuel cell system ( 10 ) according to one of claims 1 to 9 and / or a fuel cell according to claim 11 and / or a fuel cell system produced by a method according to claim 12 ( 10 ) and / or a fuel cell produced by a method according to claim 12 and / or using a fuel cell system ( 10 ) according to claim 14.

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