Solid oxide cell stack

Abstract

A solid oxide cell stack includes: a plurality of interconnects; a first solid oxide cell disposed between the plurality of interconnects and including a first fuel electrode, a first electrolyte, and a first air electrode; and a second solid oxide cell disposed adjacent to the first solid oxide cell in a lateral direction between the plurality of interconnects, and including a second fuel electrode, a second electrolyte, and a second air electrode, an operating temperature of the first solid oxide cell is higher than an operating temperature of the second solid oxide cell.

Description

Technical Field

[0001] The present disclosure relates to a solid oxide battery stack. Background Art

[0002] Solid oxide fuel cells (SOFCs) and solid oxide electrolysis cells (SOECs) may include cells formed using an air electrode, a fuel electrode, and a solid electrolyte having oxygen ion conductivity, and herein, the cells may be referred to as solid oxide cells. The solid oxide cells may generate electric power through an electrochemical reaction, or may electrolyze water through the reverse reaction of a solid oxide fuel cell to generate hydrogen. Compared with other types of electrolysis cells or fuel cells (such as phosphoric acid fuel cells (PAFCs), alkaline fuel cells (AFCs), polymer electrolyte membrane fuel cells (PEMFCs), and direct methanol fuel cells (DMFCs)), the solid oxide cells have a low overvoltage based on low activation polarization and have high efficiency with low irreversible losses. In addition, the solid oxide cells can be used as carbon fuels or hydrocarbon-based fuels as well as hydrogen, and thus have a wide fuel selection range, and have a high electrode reaction rate, so that expensive noble metals are not required as electrode catalysts.

[0003] In addition, the solid oxide cells can be used in a stacked structure and can be disposed between a pair of interconnects. In the solid oxide battery stack, in order to effectively utilize fuel and heat, a method of reusing fuel and heat by reprocessing and reinjecting the reacted gas into the same battery stack or another battery stack has been used. This method requires a waste heat recovery system for collecting waste heat and adjusting the waste heat to an appropriate temperature, or a reforming system for changing the gas concentration, which may reduce the efficiency of the solid oxide battery stack. Summary of the Invention

[0004] Technical Problem

[0005] An exemplary embodiment provides a solid oxide battery stack having improved fuel and heat utilization efficiency.

[0006] Solution to the Problem

[0007] According to an aspect of the present disclosure, a solid oxide battery stack includes: a plurality of interconnects; a first solid oxide cell disposed between the plurality of interconnects and including a first fuel electrode, a first electrolyte, and a first air electrode; and a second solid oxide cell disposed adjacent to the first solid oxide cell in a lateral direction between the plurality of interconnects and including a second fuel electrode, a second electrolyte, and a second air electrode. The operating temperature of the first solid oxide cell is higher than the operating temperature of the second solid oxide cell.

[0008] The operating temperature of the first solid oxide cell may be higher than or equal to 750 °C, and the operating temperature of the second solid oxide cell is lower than 750 °C.

[0009] The first solid oxide cell may be an electrolyte-supported cell, and the second solid oxide cell is a fuel electrode-supported cell.

[0010] The second electrolyte may be thinner than the first electrolyte.

[0011] The first fuel electrode and the second fuel electrode may include Ni and YSZ.

[0012] The content ratio of Ni in the first fuel electrode may be lower than the content ratio of Ni in the second fuel electrode.

[0013] The first electrolyte and the second electrolyte may have substantially the same thickness.

[0014] The first air electrode and the second air electrode may include different materials.

[0015] The first air electrode may include a LaMg-based ceramic, and the second air electrode includes a LaCo-based ceramic.

[0016] The first electrolyte and the second electrolyte may have substantially the same thickness.

[0017] The first electrolyte and the second electrolyte may be connected to each other to have an integral structure.

[0018] The second electrolyte may be thinner than the first electrolyte.

[0019] When the stacking direction of the plurality of interconnects is referred to as the first direction, the first solid oxide cell and the second solid oxide cell may be arranged adjacent to each other in a second direction perpendicular to the first direction.

[0020] The plurality of interconnects may include a first recess and a second recess, the first solid oxide cell is disposed in the first recess, and the second solid oxide cell is disposed in the second recess.

[0021] The first recess and the second recess may communicate with each other.

[0022] The first fuel electrode may face the bottom surface of the first recess, and the second fuel electrode may face the bottom surface of the second recess.

[0023] The plurality of interconnects may include a plurality of through holes extending in the stacking direction of the plurality of interconnects, and the plurality of through holes are disposed outside the first recess and the second recess.

[0024] Some of the plurality of through holes may be connected to the first recess, and other through holes of the plurality of through holes may be connected to the second recess.

[0025] According to another aspect of the present disclosure, a solid oxide cell stack includes: a plurality of interconnects; a first solid oxide cell of an electrolyte-supported type disposed between the plurality of interconnects; and a second solid oxide cell of a fuel electrode-supported type disposed between the plurality of interconnects.

[0026] When the stacking direction of the plurality of interconnects is referred to as a first direction, the first solid oxide cell and the second solid oxide cell may be disposed adjacent to each other in a second direction perpendicular to the first direction.

[0027] According to one aspect of the present disclosure, a solid oxide cell stack includes: a plurality of interconnects; a first solid oxide cell disposed between the plurality of interconnects and including a first fuel electrode, a first electrolyte, and a first air electrode arranged in a first direction; and a second solid oxide cell disposed between the plurality of interconnects and including a second fuel electrode, a second electrolyte, and a second air electrode arranged in the first direction. The first solid oxide cell and the second solid oxide cell are disposed in a second direction intersecting the first direction. The first solid oxide cell and the second solid oxide cell differ from each other in at least one of the following aspects: the thickness between the first electrolyte and the second electrolyte, the material composition between the first fuel electrode and the second fuel electrode, and the material composition between the first air electrode and the second air electrode.

[0028] The first fuel electrode and the second fuel electrode may include Ni and YSZ, and the content ratio of Ni in the first fuel electrode may be lower than the content ratio of Ni in the second fuel electrode.

[0029] The first air electrode may include a LaMg-based ceramic, and the second air electrode may include a LaCo-based ceramic.

[0030] The first electrolyte and the second electrolyte may be connected to each other to have an integral structure.

[0031] The first electrolyte and the second electrolyte may be spaced apart from each other.

[0032] Advantageous Effects of the Invention

[0033] In the case of a solid oxide cell stack according to an exemplary embodiment of the present disclosure, the utilization efficiency of fuel and heat can be improved. Therefore, when the solid oxide cell stack is used as a fuel cell or an electrolytic cell, the performance can be improved. Brief Description of the Drawings

[0034] Figure 1 is a perspective view schematically showing a solid oxide battery stack according to an exemplary embodiment in the present disclosure;

[0035] Figure 2 is schematically showing Figure 1 an exploded perspective view of the solid oxide battery stack;

[0036] Figure 3 is a cross-sectional view schematically showing an example of a first solid oxide battery;

[0037] Figure 4 is a cross-sectional view schematically showing an example of a second solid oxide battery;

[0038] Figure 5 is Figure 1 a schematic cross-sectional view of the solid oxide battery stack;

[0039] Figure 6 is a cross-sectional view schematically showing another example of the first solid oxide battery and the second solid oxide battery;

[0040] Figure 7 is a schematic cross-sectional view showing another example of the first solid oxide battery and the second solid oxide battery;

[0041] Figure 8 is an exploded perspective view schematically showing a solid oxide battery stack according to another exemplary embodiment in the present disclosure;

[0042] Figure 9 is showing Figure 8 a schematic cross-sectional view of the solid oxide battery stack; and

[0043] Figure 10 is a cross-sectional view schematically showing examples of the first solid oxide battery and the second solid oxide battery that can be used in an exemplary embodiment for Figure 8 the. Detailed Description of the Embodiments

[0044] Hereinafter, exemplary embodiments of the inventive concept will be described in detail with reference to the drawings. However, the inventive concept can be illustrated in many different forms and should not be construed as limited to the specific exemplary embodiments set forth herein. Rather, these exemplary embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the inventive concept to those skilled in the art. In the drawings, the shapes and sizes of elements may be exaggerated for clarity, and the same reference numerals will always be used to denote the same or similar elements.

[0045] To clarify the present disclosure, parts not relevant to the description are omitted, and like reference numerals refer to like elements throughout the specification. In the drawings, for clarity, the thicknesses of layers, films, panels, regions, etc. are exaggerated. Further, in the drawings, although like reference numerals are shown in different drawings, they refer to like elements. Throughout the specification, unless explicitly described to the contrary, the word "comprising" and variations thereof (such as "comprises" or "comprising") will be understood to imply the inclusion of the stated elements but not the exclusion of any other elements.

[0046] Figure 1 and Figure 2 Schematically shown are a solid oxide battery stack according to an exemplary embodiment in the present disclosure, corresponding to a perspective view and an exploded perspective view, respectively. Figure 3 and Figure 4 are cross-sectional views schematically showing examples of a first solid oxide battery and a second solid oxide battery, respectively. Figure 5 is Figure 1 a schematic cross-sectional view of the solid oxide battery stack.

[0047] Referring to Figures 1 to 5 , the solid oxide battery stack 100 according to an exemplary embodiment in the present disclosure includes, as main components, a plurality of interconnects 110, a first solid oxide battery 120, and a second solid oxide battery 130. The second solid oxide battery 130 is disposed adjacent to the first solid oxide battery 120 in the lateral direction. Here, the operating temperature of the first solid oxide battery 120 is higher than that of the second solid oxide battery 130. As in this exemplary embodiment, by using solid oxide batteries 120 and 130 having different operating temperatures in a single solid oxide battery stack 100, the utilization rate of fuel and heat can be significantly improved. That is, different from a stack that only includes batteries having the same characteristics and whose efficiency decreases as the reaction proceeds during driving, in the exemplary embodiment in the present disclosure, by effectively arranging the batteries 120 and 130 having different optimal driving conditions, high efficiency can be maintained during driving. Hereinafter, the components of the solid oxide battery stack 100 will be described in detail.

[0048] The plurality of interconnects 110 may be formed of a material having excellent electrical conductivity and low degradation degree in a high-temperature environment. As a specific example, the plurality of interconnects 110 may be formed of a metal such as stainless steel, nickel, iron, or copper. The plurality of interconnects 110 may be electrically connected to the first solid oxide cell 120 and the second solid oxide cell 130. In this case, a plurality of first solid oxide cells 120 and a plurality of second solid oxide cells 130 may be provided and implemented in a stacked structure. In other words, the first solid oxide cell 120 and the second solid oxide cell 130 may be disposed on the upper interconnect 110 among the plurality of interconnects 110, and three or more interconnects 110 may be repeatedly stacked. The plurality of interconnects 110 may have a flat plate structure, and may further include recesses R1 and R2 in which the solid oxide cells 120 and 130 may be disposed, or flow paths F and through holes H through which fuel and air may diffuse. As will be described below, these additional elements of the interconnect 110 may facilitate fluid flow between the first solid oxide cell 120 and the second solid oxide cell 130 having different driving characteristics, thereby obtaining high efficiency.

[0049] The first solid oxide cell 120 and the second solid oxide cell 130 may be disposed between the plurality of interconnects 110 and may correspond to functional layers of a fuel cell or an electrolytic cell. In this case, the first solid oxide cell 120 and the second solid oxide cell 130 may be disposed in the first recess R1 and the second recess R2 of the interconnect 110, and the flow path F may be formed in the first recess R1 and the second recess R2 of the interconnect 110. The driving temperature of the first solid oxide cell 120 may be higher than the operating temperature of the second solid oxide cell 130, and such driving conditions may be achieved by specific exemplary embodiments in the present disclosure as will be described below. Refer to Figure 3 , the first solid oxide cell 120 may include a first fuel electrode 121, a first electrolyte 122, and a first air electrode 123. In this case, the first electrolyte 122 may be disposed between the first fuel electrode 121 and the first air electrode 123. In addition, refer to Figure 4 , the second solid oxide cell 130 may include a second fuel electrode 131, a second electrolyte 132, and a second air electrode 133. In this case, the second electrolyte 132 may be disposed between the second fuel electrode 131 and the second air electrode 133. In addition, as Figure 5 shown, the first solid oxide cell 120 may be disposed such that the first fuel electrode 121 faces the bottom surface of the first recess R1. Similarly, the second solid oxide cell 120 may be disposed such that the second fuel electrode 131 faces the bottom surface of the second recess R2.

[0050] When used as a fuel cell, in the fuel electrodes 121 and 131, water may be generated due to the oxidation of hydrogen or an oxidation reaction of a carbon compound may occur, and in the air electrodes 123 and 133, an oxygen ion generation reaction may occur due to the decomposition of oxygen. When used as an electrolytic cell, the reverse reactions may occur. For example, hydrogen may be generated according to the reduction reaction of water in the fuel electrodes 121 and 131, and oxygen may be generated in the air electrodes 123 and 133. As another example, when used as a fuel cell, a hydrogen decomposition (generating hydrogen ions) reaction may occur in the fuel electrodes 121 and 131, and oxygen ions and hydrogen ions may combine to generate water in the air electrodes 123 and 133. In the case of an electrolytic cell, a water decomposition reaction (generating hydrogen ions and oxygen ions) may occur in the fuel electrodes 121 and 131, and oxygen may be generated in the air electrodes 123 and 133. Additionally, ions may move from the first electrolyte 122 to the first fuel electrode 121 or the first air electrode 123, and from the second electrolyte 132 to the second fuel electrode 131 or the second air electrode 133.

[0051] The components of the first solid oxide cell 120 and the second solid oxide cell 130, namely, the first fuel electrode 121 and the second fuel electrode 131, the first electrolyte 122 and the second electrolyte 132, and the first air electrode 123 and the second air electrode 133 may include solid oxides. Specifically, the first fuel electrode 121 and the second fuel electrode 131 may include a cermet layer that includes a metal-containing phase and a ceramic phase. Here, the metal-containing phase may include a metal catalyst that acts as an electron conductor, such as nickel (Ni), cobalt (Co), copper (Cu), or an alloy thereof. The metal catalyst may be in a metallic state or may be in an oxidized state. In the case of the ceramic phase of the first fuel electrode 121 and the second fuel electrode 131, gadolinium-doped ceria (GDC), samarium-doped ceria (SDC), yttrium-doped ceria (YDC), scandium-stabilized zirconia (SSZ), ytterbium cerium scandium-stabilized zirconia (YbCSSZ), etc.

[0052] The first electrolyte 122 and the second electrolyte 132 may include stabilized zirconia. Specifically, the first electrolyte 122 and the second electrolyte 132 may include scandium-stabilized zirconia (SSZ), yttrium-stabilized zirconia (YSZ), scandium ceria-stabilized zirconia (SCSZ), scandium ceria yttrium-stabilized zirconia (SCYSZ), and scandium ceria ytterbium-stabilized zirconia (SCYbSZ), etc.

[0053] The first air electrode 123 and the second air electrode 133 may include an electronically conductive material, e.g., an electronically conductive perovskite material such as lanthanum strontium manganese (LSM). Other conductive perovskites may also be used, e.g., such as lanthanum strontium cobalt (LSC), lanthanum strontium cobalt manganese (LSCM), lanthanum strontium cobalt ferrite (LSCF), lanthanum strontium ferrite (LSF), La 0.85 Sr 0.15 Cr 0.9 Ni 0.1 O3 (LSCN) or a metal such as Pt. In some exemplary embodiments, the first air electrode 123 and the second air electrode 133 may include a mixture of an electronically conductive material and an ionically conductive ceramic material. For example, the first air electrode 123 and the second air electrode 133 may include about 10 wt% to about 90 wt% of an electronically conductive material (e.g., LSM, etc.) and about 10 wt% to about 90 wt% of an ionically conductive material. Here, the ionically conductive material may include a zirconia-based material and / or a ceria-based material.

[0054] Furthermore, although this exemplary embodiment shows an example in which two solid oxide cells 120 and 130 are disposed between a plurality of interconnects 110, a greater number of solid oxide cells (i.e., three or more solid oxide cells) may also be provided as needed. In this case, the shape of the interconnects 110 may be appropriately modified accordingly. When the number of solid oxide cells 120 and 130 is three or more, the operating temperatures of at least two of the solid oxide cells 120 and 130 may be different.

[0055] In the case of this exemplary embodiment, as described above, the operating temperature of the first solid oxide cell 120 may be higher than the operating temperature of the second solid oxide cell 130, where the operating temperatures of the solid oxide cells 120 and 130 may be the optimum operating temperatures for high power generation efficiency or electric efficiency. As a specific example, the operating temperature of the first solid oxide cell 120 may be higher than or equal to 750 °C, and the operating temperature of the second solid oxide cell 130 may be lower than 750 °C. In Figure 2 which, the arrows indicate the flow of fuel and air when used as an electrolytic cell. Specifically, the solid lines indicate the flow of fuel, and the dashed lines indicate the flow of air. As Figure 2As shown, the temperature of the fuel passing through the first solid oxide cell 120 having a relatively high operating temperature decreases due to the endothermic reaction when used as an electrolytic cell, and the partial pressure of the fuel also decreases due to the use of the fuel. The fuel with decreased temperature and partial pressure may move toward the second solid oxide cell 130 having a relatively low operating temperature, and a high-efficiency reaction may occur in the second solid oxide cell 130. As in this exemplary embodiment, a high-efficiency reaction can be maintained by arranging the solid oxide cells 120 and 130 having different operating temperatures adjacent to each other in the fuel flow direction. In this case, the first solid oxide cell 120 and the second solid oxide cell 130 can be arranged adjacent to each other in the lateral direction. More specifically, when the stacking direction of the plurality of interconnects 110 is referred to as the first direction D1, the first solid oxide cell 120 and the second solid oxide cell 130 can be arranged adjacent to each other in a second direction D2 perpendicular to the first direction D1.

[0056] As Figure 2 shown, the first recess R1 and the second recess R2 provided in the interconnect 110 can be arranged to communicate with each other to facilitate the flow of fuel or air between the first solid oxide cell 120 and the second solid oxide cell 130. Additionally, the plurality of interconnects 110 can include a plurality of through holes H formed in the thickness direction (i.e., in the first direction D1 in the drawing). In this case, the plurality of through holes H can be arranged outside the first recess R1 and the second recess R2. Further, some of the plurality of through holes H can be connected to the first recess R1, and other through holes H of the plurality of through holes H can be connected to the second recess R2. Further, above, the case where the solid oxide cell stack 100 is used as an electrolytic cell has been described, and when the solid oxide cell stack 100 is used as a fuel cell, the gradient of the temperature or partial pressure of the fuel may appear opposite.

[0057] As an example for distinguishing the operating temperatures of the first solid oxide cell 120 and the second solid oxide cell 130, the thicknesses of the electrolytes 122 and 132 included in the first solid oxide cell 120 and the second solid oxide cell 130, respectively, can be adjusted. More specifically, as Figure 3 shown, the first solid oxide cell 120 can be a so-called electrolyte-supported cell in which the first fuel electrode 121 and the first air electrode 123 are supported by the first electrolyte 122, and in this case, the first electrolyte 122 can be the thickest and widest. In contrast, in the case of the second solid oxide cell 130, as Figure 4As shown, the second fuel electrode 131 can be the thickest fuel electrode-supported cell. Since the electrolytes 122 and 132 have relatively high resistance, the operating temperature may increase when the electrolytes 122 and 132 are formed thick. Because the fuel electrode is relatively thin and stable against degradation caused by oxidation, i.e., has excellent durability, such an electrolyte-supported cell can operate efficiently at high temperatures. Thus, in the case of an electrolyte-supported cell such as the first solid oxide cell 120, when the first electrolyte 122 is relatively thick, the operating temperature can be higher than the operating temperature of the second solid oxide cell 130, and in the case of a fuel electrode-supported cell such as the second solid oxide cell 130, the ionic conductivity can be relatively high, such that the second solid oxide cell 130 can be driven efficiently even at low temperatures. However, the second solid oxide cell 130 can be implemented as a cell with a lower operating temperature, such as a metal-supported cell, rather than a fuel electrode-supported cell. In addition, the second solid oxide cell 130 can be a fuel electrode-supported cell and can additionally include a metal-supported cell or the like. Further, in the case where the difference in operating temperature is reliably achieved by adopting different supported solid oxide cells 120 and 130 as in this exemplary embodiment, the arrangement method of the first solid oxide cell 120 and the second solid oxide cell 130 does not have to be strictly limited to the form in which the first solid oxide cell 120 and the second solid oxide cell 130 are spaced apart from each other in the lateral direction.

[0058] Reference will be made to Figure 6 and Figure 7 to describe the first solid oxide cell and the second solid oxide cell according to a variant example. First, in the case of Figure 6 the second electrolyte 132 corresponds to a structure thinner than the first electrolyte 122, regardless of the shape of the electrolyte-supported or fuel electrode-supported type. Thus, for the reasons described above, the operating temperature of the first metal oxide cell 120 can be higher than the operating temperature of the second metal oxide cell 130. Next, in the case of Figure 7In this case, the difference in operating temperature between the first solid oxide battery 120 and the second solid oxide battery 130 is achieved by utilizing the material properties of the first fuel electrode 121 and the second fuel electrode 131, as well as the material properties of the first air electrode 123 and the second air electrode 133. In this case, the first electrolyte 122 and the second electrolyte 132 may have substantially the same thickness. First, the first fuel electrode 121 and the second fuel electrode 131 may include Ni and YSZ, and the difference in operating temperature may be generated by changing the mixing ratio of Ni and YSZ. That is, as the ratio of Ni decreases and the ratio of YSZ increases, the operating temperature may increase. Therefore, the content ratio of Ni in the first fuel electrode 121 may be lower than the content ratio of Ni in the second fuel electrode 131. Here, the content ratio of Ni may refer to wt%, and the Ni content in the first fuel electrode 121 and the second fuel electrode 131 may be relatively measured, so the content ratio of Ni may refer to mol% rather than wt%.

[0059] In Figure 7 In the example of, the materials of the first air electrode 123 and the second air electrode 133 may be adjusted, and the materials of the first fuel electrode 121 and the second fuel electrode 131 may also be adjusted simultaneously or individually. Specifically, the first air electrode 123 and the second air electrode 133 may include different types of materials. More specifically, the first air electrode 123 may include a LaMg-based ceramic (e.g., LSM) having a relatively high operating temperature, and the second air electrode 133 may include a LaCo-based ceramic (e.g., LSC) having a relatively low operating temperature.

[0060] In this way, the difference in operating temperature between the first solid oxide battery 120 and the second solid oxide battery 130 can be achieved by adjusting the materials of the first fuel electrode 121 and the second fuel electrode 131 and the materials of the air electrodes 123 and 133 through the difference in thickness between the first electrolyte 122 and the second electrolyte 132.

[0061] Figure 8 is an exploded perspective view schematically showing a solid oxide battery stack according to another exemplary embodiment in the present disclosure, Figure 9 is schematically showing Figure 8 of the solid oxide battery stack. In addition, Figure 10 is schematically showing an example that can be used for Figure 8 in the exemplary embodiment of the first solid oxide battery and the second solid oxide battery.

[0062] Referring to Figures 8 to 10, in the present exemplary embodiment, the solid oxide battery stack 200 includes a plurality of interconnects 210, a first solid oxide battery 220, and a second solid oxide battery 230 as main components. Here, the operating temperature of the first solid oxide battery 220 is higher than that of the second solid oxide battery 230. Different from the previous exemplary embodiment, the first electrolyte 222 and the second electrolyte 232 can be connected to each other to form an integral structure. In this case, the first solid oxide battery 220 and the second solid oxide battery 230 can be arranged in a single recess R provided in the interconnect 210. The first electrolyte 222 and the second electrolyte 232, which are implemented as an integral structure in the present exemplary embodiment, can be advantageous in manufacturing or processing the solid oxide batteries 220 and 230, and can be suitable for miniaturizing the solid oxide battery stack 200. In order to make the operating temperatures of the first solid oxide battery 220 and the second solid oxide battery 230 different, the materials of the fuel electrodes 221 and 231 and the materials of the air electrodes 223 and 233 can be adjusted, or the thicknesses of the first electrolyte 222 and the second electrolyte 232 can be adjusted in the same manner as described above.

[0063] For example, as in Figure 9 the example, when the first electrolyte 222 and the second electrolyte 232 have substantially the same thickness, the first fuel electrode 221 and the second fuel electrode 231 can include Ni and YSZ, and the content ratio of Ni in the first fuel electrode 221 can be lower than the content ratio of Ni in the second fuel electrode 231. In addition, the materials of the first air electrode 223 and the second air electrode 233 can be adjusted, and the materials of the first air electrode 223 and the second air electrode 233 can also be adjusted simultaneously or individually. Specifically, the first air electrode 223 and the second air electrode 233 can include different types of materials. More specifically, the first air electrode 223 can include a LaMg-based ceramic (e.g., LSM) having a relatively high operating temperature, and the second air electrode 233 can include a LaCo-based ceramic (e.g., LSC) having a relatively low operating temperature.

[0064] In addition, as in Figure 10 the example, the first electrolyte 222 and the second electrolyte 232 can form an integral structure with each other, while the second electrolyte 233 can be thinner than the first electrolyte 232, and even in this form, the operating temperature of the first solid oxide battery 220 can be achieved to be higher than that of the second solid oxide battery 230.

[0065] Configurations that make the operating temperature of the first solid oxide cell higher than that of the second solid oxide cell can be achieved by combining two or more of the above examples. For example, an example with a thickness difference and an example with a material composition difference can be combined such that the operating temperature of the first solid oxide cell can be higher than that of the second solid oxide cell, but the present disclosure is not limited thereto. Some repetitive descriptions will be omitted to avoid redundancy.

[0066] In the case of a solid oxide cell stack according to an exemplary embodiment of the present disclosure, the utilization efficiency of fuel and heat can be improved. Therefore, when the solid oxide cell stack is used as a fuel cell or an electrolytic cell, the performance can be improved.

[0067] Although the exemplary embodiments have been shown and described above, it will be readily understood by those skilled in the art that modifications and variations can be made without departing from the scope of the present disclosure defined by the appended claims.

Claims

1. A solid oxide cell stack, comprising: A plurality of interconnects; A first solid oxide cell disposed between the plurality of interconnects and including a first fuel electrode, a first electrolyte, and a first air electrode; And A second solid oxide cell disposed adjacent to the first solid oxide cell in a lateral direction between the plurality of interconnects and including a second fuel electrode, a second electrolyte, and a second air electrode, Wherein, the operating temperature of the first solid oxide cell is higher than the operating temperature of the second solid oxide cell.

2. The solid oxide battery stack according to claim 1, wherein, The operating temperature of the first solid oxide cell is higher than or equal to 750 °C, and the operating temperature of the second solid oxide cell is lower than 750 °C.

3. The solid oxide battery stack according to claim 1, wherein, The first solid oxide cell is an electrolyte-supported cell, and the second solid oxide cell is a fuel electrode-supported cell.

4. The solid oxide battery stack according to claim 1, wherein, The second electrolyte is thinner than the first electrolyte.

5. The solid oxide battery stack according to claim 1, wherein, The first fuel electrode and the second fuel electrode include Ni and YSZ.

6. The solid oxide battery stack according to claim 5, wherein, The content ratio of Ni in the first fuel electrode is lower than the content ratio of Ni in the second fuel electrode.

7. The solid oxide cell stack according to claim 6, wherein, The first electrolyte and the second electrolyte have substantially the same thickness.

8. The solid oxide battery stack according to claim 1, wherein, The first air electrode and the second air electrode include different materials.

9. The solid oxide battery stack according to claim 8, wherein, The first air electrode includes a LaMg-based ceramic, and the second air electrode includes a LaCo-based ceramic.

10. The solid oxide battery stack according to claim 9, wherein, The first electrolyte and the second electrolyte have substantially the same thickness.

11. The solid oxide battery stack according to claim 1, wherein, The first electrolyte and the second electrolyte are connected to each other to have an integral structure.

12. The solid oxide battery stack according to claim 11, wherein, The second electrolyte is thinner than the first electrolyte.

13. The solid oxide battery stack according to claim 1, wherein, When the stacking direction of the plurality of interconnects is referred to as the first direction, the first solid oxide cell and the second solid oxide cell are arranged adjacent to each other in a second direction perpendicular to the first direction.

14. The solid oxide battery stack according to claim 1, wherein, The plurality of interconnects include a first recess and a second recess, the first solid oxide cell is disposed in the first recess, and the second solid oxide cell is disposed in the second recess.

15. The solid oxide battery stack according to claim 14, wherein, The first recess and the second recess communicate with each other.

16. The solid oxide battery stack according to claim 14, wherein, The first fuel electrode faces the bottom surface of the first recess, and the second fuel electrode faces the bottom surface of the second recess.

17. The solid oxide battery stack according to claim 14, wherein, The plurality of interconnects include a plurality of through holes extending in the stacking direction of the plurality of interconnects, and the plurality of through holes are arranged outside the first recess and the second recess.

18. The solid oxide battery stack according to claim 17, wherein, Some of the plurality of through holes are connected to the first recess, and other through holes of the plurality of through holes are connected to the second recess.

19. A solid oxide cell stack, comprising: A plurality of interconnects; A first solid oxide cell of electrolyte-supported type disposed between the plurality of interconnects; And A second solid oxide cell of fuel electrode-supported type disposed between the plurality of interconnects.

20. The solid oxide battery stack according to claim 19, wherein, When the stacking direction of the plurality of interconnects is referred to as the first direction, the first solid oxide cell and the second solid oxide cell are arranged adjacent to each other in a second direction perpendicular to the first direction.

21. A solid oxide cell stack, comprising: A plurality of interconnects; A first solid oxide cell, disposed between the plurality of interconnects and including a first fuel electrode, a first electrolyte, and a first air electrode arranged in a first direction; and A second solid oxide cell, disposed between the plurality of interconnects and including a second fuel electrode, a second electrolyte, and a second air electrode arranged in the first direction, wherein the first solid oxide cell and the second solid oxide cell are disposed in a second direction intersecting the first direction, and the first solid oxide cell and the second solid oxide cell are different from each other in at least one of the following aspects: the thickness between the first electrolyte and the second electrolyte, the material composition between the first fuel electrode and the second fuel electrode, and the material composition between the first air electrode and the second air electrode.

22. The solid oxide battery stack according to claim 21, wherein, The first fuel electrode and the second fuel electrode include Ni and YSZ, and the content ratio of Ni in the first fuel electrode is lower than the content ratio of Ni in the second fuel electrode.

23. The solid oxide battery stack according to claim 22, wherein, The first electrolyte and the second electrolyte have substantially the same thickness.

24. The solid oxide battery stack according to claim 21, wherein, The first air electrode includes a LaMg-based ceramic, and the second air electrode includes a LaCo-based ceramic.

25. The solid oxide battery stack according to claim 24, wherein, The first electrolyte and the second electrolyte have substantially the same thickness.

26. The solid oxide battery stack according to claim 21, wherein, The first electrolyte and the second electrolyte are connected to each other to have an integral structure.

27. The solid oxide battery stack according to claim 21, wherein, The first electrolyte and the second electrolyte are spaced apart from each other.

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