Electrochemical cell, electrochemical cell device, module, and module housing device

Abstract

The electrochemical cell includes a solid electrolyte layer and a first electrode. The solid electrolyte layer contains an ion-conductive first material in which a rare earth element is solid-solved. The first electrode contains a rare earth element, and has a first surface in contact with the solid electrolyte layer and a second surface on the opposite side from the first surface. The second surface side of the first electrode has a higher rare earth element content than the first surface side.

Description

Technical Field

[0001] The present disclosure relates to an electrochemical cell unit, an electrochemical cell unit device, a module, and a module housing device. Background Art

[0002] In recent years, as next-generation energy, various fuel cell unit stack devices having a plurality of fuel cell units have been proposed. A fuel cell unit is a type of electrochemical cell unit that can generate electric power using a fuel gas such as a hydrogen-containing gas and an oxygen-containing gas such as air.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2014-524655 Summary of the Invention

[0006] An electrochemical cell unit according to one aspect of the embodiment includes a solid electrolyte layer and a first electrode. The solid electrolyte layer contains a first material having ion conductivity in which a rare earth element is solid-dissolved. The first electrode contains a rare earth element and has a first surface in contact with the solid electrolyte layer and a second surface on the side opposite to the first surface. The content rate of the rare earth element on the second surface side of the first electrode is larger than that on the first surface side.

[0007] In addition, an electrochemical cell unit device of the present disclosure has a cell unit stack including the electrochemical cell unit described above.

[0008] In addition, a module of the present disclosure includes the electrochemical cell unit device described above and a storage container for storing the electrochemical cell unit device.

[0009] In addition, a module housing device of the present disclosure includes: the module described above; auxiliary equipment for operating the module; and an outer housing for housing the module and the auxiliary equipment. Brief Description of the Drawings

[0010] Figure 1A It is a cross-sectional view showing an example of the electrochemical cell unit according to the first embodiment.

[0011] Figure 1B It is a side view showing an example of the electrochemical cell unit according to the first embodiment as viewed from the air electrode side.

[0012] Figure 1C It is a side view showing an example of the electrochemical cell unit according to the first embodiment as viewed from the interconnector side.

[0013] Figure 2A It is a perspective view showing an example of the electrochemical cell unit device according to the first embodiment.

[0014] Figure 2B is Figure 2A a cross-sectional view along the X-X line shown in the figure.

[0015] Figure 2C is a top view showing an example of an electrochemical cell unit device according to the first embodiment.

[0016] Figure 3A is to Figure 1A enlarge the cross-sectional view of the region R1 shown in the figure.

[0017] Figure 3B is an enlarged cross-sectional view showing another example of an electrochemical cell according to the first embodiment.

[0018] Figure 4 is an external perspective view showing an example of a module according to the first embodiment.

[0019] Figure 5 is an exploded perspective view schematically showing an example of a module housing device according to the first embodiment.

[0020] Figure 6 is a cross-sectional view of an electrochemical cell unit device according to the second embodiment.

[0021] Figure 7 is a cross-sectional view showing an example of an electrochemical cell according to the second embodiment.

[0022] Figure 8 is to Figure 7 enlarge the cross-sectional view of the region R2 shown in the figure.

[0023] Figure 9A is a perspective view showing an example of an electrochemical cell according to the third embodiment.

[0024] Figure 9B is Figure 9A a partial cross-sectional view of the electrochemical cell shown in the figure.

[0025] Figure 9C is to Figure 9B enlarge the cross-sectional view of the region R3 shown in the figure.

[0026] Figure 10A is a cross-sectional view showing an example of an electrochemical cell according to the fourth embodiment.

[0027] Figure 10B is a cross-sectional view showing another example of an electrochemical cell according to the fourth embodiment.

[0028] Figure 10C is a cross-sectional view showing another example of an electrochemical cell according to the fourth embodiment.

[0029] Figure 11 is a sectional view showing an enlarged view of the region R4 shown in Figure 10A shown. Detailed Embodiment

[0030] In the above fuel cell unit stack device, there is room for improvement in terms of improving performance.

[0031] Therefore, it is expected to provide an electrochemical cell unit, an electrochemical cell unit device, a module, and a module housing device that can improve performance.

[0032] Hereinafter, with reference to the drawings, embodiments of the electrochemical cell unit, the electrochemical cell unit device, the module, and the module housing device disclosed in the present application will be described in detail. It should be noted that the present disclosure is not limited by the embodiments shown below.

[0033] In addition, it should be noted that the drawings are schematic, and the dimensional relationships of the respective elements, the ratios of the respective elements, etc. are sometimes different from the actual ones. Furthermore, among the drawings, there are sometimes also parts where the dimensional relationships and ratios of each other are different.

[0034] [First Embodiment]

[0035] <Configuration of Electrochemical Cell Unit>

[0036] First, with reference to Figures 1A - 1C , as an example of an electrochemical cell unit constituting an electrochemical cell unit device of the first embodiment, an example of a solid oxide type fuel cell unit is used for explanation. The electrochemical cell unit device may include a cell unit stack having a plurality of electrochemical cell units. The electrochemical cell unit device having a plurality of electrochemical cell units is sometimes simply referred to as a cell unit stack device.

[0037] Figure 1A is a cross-sectional view showing an example of an electrochemical cell unit of the first embodiment. Figure 1B is a side view showing an example of an electrochemical cell unit of the first embodiment as viewed from the air electrode side. Figure 1C is a side view showing an example of an electrochemical cell unit of the first embodiment as viewed from the interconnect side. It should be noted that Figures 1A - 1C a part of each configuration of the electrochemical cell unit is enlarged and shown. Hereinafter, the electrochemical cell unit is sometimes simply referred to as a cell unit.

[0038] In Figures 1A - 1C the example shown, the cell unit 1 is a hollow flat plate type and is an elongated plate shape. As Figure 1BAs shown, when observing the overall shape of the battery cell 1 from the side, for example, the length of the side in the length direction L is 5 cm to 50 cm, and the length in the width direction W orthogonal to the length direction L is, for example, 1 cm to 10 cm, forming a rectangle. The thickness in the thickness direction T of the overall battery cell 1 is, for example, 1 mm to 5 mm.

[0039] As Figure 1A shown, the battery cell 1 includes a conductive support substrate 2, an element portion 3, and an interconnector 4. The support substrate 2 is columnar with a pair of opposing first surface n1, second surface n2, and a pair of arc-shaped side surfaces m connecting the first surface n1 and the second surface n2.

[0040] The element portion 3 is provided on the first surface n1 of the support substrate 2. The element portion 3 has a fuel electrode layer 5, a solid electrolyte layer 6, and an air electrode layer 8. Additionally, in Figure 1A the example shown, the interconnector 4 is located on the second surface n2 of the battery cell 1. It should be noted that the battery cell 1 may also have an intermediate layer 7 between the solid electrolyte layer 6 and the air electrode layer 8.

[0041] Additionally, as Figure 1B shown, the air electrode layer 8 does not extend to the lower end of the battery cell 1. At the lower end portion of the battery cell 1, only the solid electrolyte layer 6 is exposed on the surface of the first surface n1. Additionally, as Figure 1C shown, the interconnector 4 may also extend to the lower end of the battery cell 1. At the lower end portion of the battery cell 1, the interconnector 4 and the solid electrolyte layer 6 are exposed on the surface. It should be noted that, as Figure 1A shown, on the surface of the pair of arc-shaped side surfaces m of the battery cell 1, the solid electrolyte layer 6 is exposed. The interconnector 4 may not extend to the lower end of the battery cell 1.

[0042] Hereinafter, each component constituting the battery cell 1 will be described.

[0043] The support substrate 2 has a gas flow path 2a inside for gas to flow through. Figure 1A The example of the support substrate 2 shown has six gas flow paths 2a. The support substrate 2 has gas permeability, allowing the fuel gas flowing in the gas flow path 2a to permeate to the fuel electrode layer 5. The support substrate 2 may also have conductivity. The conductive support substrate 2 collects the electricity generated in the element portion 3 to the interconnector 4.

[0044] The material of the support substrate 2, for example, contains an iron group metal component and an inorganic oxide. The iron group metal component may, for example, be Ni (nickel) and / or NiO. The inorganic oxide may, for example, be a specific rare earth element oxide. The rare earth element oxide may, for example, contain one or more rare earth elements selected from Sc, Y, La, Nd, Sm, Gd, Dy, and Yb.

[0045] The fuel electrode layer 5 may also use a porous conductive ceramic, such as a ZrO solid-solution containing calcium oxide, magnesium oxide, or rare earth element oxide, 2 etc., such as a ceramic containing an oxide with ionic conductivity, such as the above-mentioned oxides, and a metal with electronic conductivity, such as Ni. The rare earth element oxide may, for example, contain a variety of rare earth elements selected from Sc, Y, La, Nd, Sm, Gd, Dy, and Yb. Sometimes, ZrO solid-solution containing calcium oxide, magnesium oxide, or rare earth element oxide 2 is called stabilized zirconia. Stabilized zirconia may also include partially stabilized zirconia. The conductive ceramic may, for example, be a ceramic containing a material for the solid electrolyte layer 6 described later and Ni and / or NiO. It should be noted that the details of the fuel electrode layer 5 will be described later.

[0046] The solid electrolyte layer 6 is an electrolyte that conducts ions between the fuel electrode layer 5 and the air electrode layer 8. At the same time, the solid electrolyte layer 6 has gas barrier properties and is not prone to leakage of fuel gas and oxygen-containing gas.

[0047] The solid electrolyte layer 6 contains a first material with ionic conductivity containing a rare earth element in solid solution. The first material may, for example, be an oxide ion conductor with oxide ion conductivity or a proton conductor with proton conductivity. As the oxide ion conductor, for example, it may be ZrO 2 or CeO 2 . As the proton conductor, for example, it may be one or more of the materials with a perovskite structure containing Zr and / or Ce.

[0048] The rare earth element contains, for example, one or more elements selected from Sc, Y, La, Nd, Sm, Gd, Dy, and Yb. The rare earth element may also exist as a rare earth oxide. The rare earth element may not contain Ce.

[0049] The material of the solid electrolyte layer 6 may, for example, be ZrO 2 or CeO 2 in which 3 mol% to 25 mol% of rare earth element oxide is in solid solution. The material of the solid electrolyte layer 6 may, for example, be stabilized zirconia containing Yb. The solid electrolyte layer 6 may, for example, contain perovskite-type compounds such as BaZrO 3 and SrZrO 3 in which rare earth elements such as Sc, Y, La, Nd, Sm, Gd, Dy, and Yb are in solid solution.

[0050] The air electrode layer 8 has air permeability. The air electrode layer 8 is an example of the second electrode layer. The open porosity of the air electrode layer 8 may, for example, be 20% to 50%, and particularly preferably in the range of 30% to 50%.

[0051] There is no particular limitation on the material of the air electrode layer 8 as long as it is a material commonly used for air electrodes. For example, the material of the air electrode layer 8 can also be a conductive ceramic such as a so-called ABO 3 type perovskite oxide.

[0052] For example, the material of the air electrode layer 8 can be a composite oxide in which Sr (strontium) and La (lanthanum) coexist at the A site. As an example of such a composite oxide, La x Sr 1-x Co y Fe 1-y O 3 、La x Sr 1-x MnO 3 、La x Sr 1-x FeO 3 、La x Sr 1-x CoO 3 etc. It should be noted that x is 0 < x < 1 and y is 0 < y < 1.

[0053] In addition, when the component part 3 has the intermediate layer 7, the intermediate layer 7 has the function of a diffusion suppression layer. When elements such as Sr (strontium) contained in the air electrode layer 8 diffuse into the solid electrolyte layer 6, a resistance layer such as SrZrO 3 etc. is formed on the solid electrolyte layer 6. By making Sr difficult to diffuse, the intermediate layer 7 makes it difficult to form oxides with electrical insulation properties such as SrZrO 3 .

[0054] There is no particular limitation on the material of the intermediate layer 7 as long as it is a material that generally does not easily cause diffusion of elements between the air electrode layer 8 and the solid electrolyte layer 6. For example, the material of the intermediate layer 7 can contain cerium oxide (CeO 2 ) in which rare earth elements other than Ce (cerium) are solid-solved. As such rare earth elements, for example, Gd (gadolinium), Sm (samarium), etc. can also be used.

[0055] In addition, the interconnect 4 is dense and does not easily cause leakage of the fuel gas flowing in the gas flow path 2a inside the support substrate 2 and the oxygen-containing gas flowing outside the support substrate 2. The interconnect 4 can have a relative density of 93% or more, particularly 95% or more.

[0056] As the material of the interconnect 4, a perovskite oxide of the lanthanum chromate series (LaCrO 3 series oxide), a perovskite oxide of the lanthanum strontium titanium series (LaSrTiO 3such as oxide systems. These materials have electrical conductivity and are not easily reduced or oxidized even when in contact with fuel gases such as hydrogen-containing gases and oxygen-containing gases such as air. In addition, metals or alloys can also be used as the material for the interconnect 4.

[0057] <Structure of the electrochemical cell unit device>

[0058] Next, with reference to Figures 2A - 2C the electrochemical cell unit device of the present embodiment using the above-described electrochemical cell unit will be described. Figure 2A is a perspective view showing an example of the electrochemical cell unit device of the first embodiment. Figure 2B is Figure 2A a cross-sectional view taken along the line X-X shown in Figure 2C is a top view showing an example of the electrochemical cell unit device of the first embodiment.

[0059] As Figure 2A shown, the cell unit stack device 10 includes a cell unit stack 11 and a fixing member 12. The cell unit stack 11 has a plurality of cell units 1 arranged (stacked) in the thickness direction T of the cell unit 1 (refer to Figure 1A ).

[0060] The fixing member 12 has a fixing piece 13 and a support member 14. The support member 14 supports the cell unit 1. The fixing piece 13 fixes the cell unit 1 to the support member 14. In addition, the support member 14 has a support body 15 and a gas tank 16. The support body 15 and the gas tank 16 of the support member 14 are, for example, made of metal and have electrical conductivity.

[0061] As Figure 2B shown, the support body 15 has insertion holes 15a into which the lower ends of the plurality of cell units 1 are inserted. The lower ends of the plurality of cell units 1 are joined to the inner wall of the insertion holes 15a by the fixing piece 13.

[0062] The gas tank 16 has an opening for supplying reaction gas to the plurality of cell units 1 through the insertion holes 15a and a groove 16a located around the opening. The end of the outer periphery of the support body 15 is joined to the gas tank 16 by a joining member 21 filled in the groove 16a of the gas tank 16.

[0063] In Figure 2A the example shown, a fuel gas is stored in the internal space 22 formed by the support body 15 and the gas tank 16 of the support member 14. A gas flow pipe 20 is connected to the gas tank 16. The fuel gas is supplied to the gas tank 16 through the gas flow pipe 20 and is supplied from the gas tank 16 to the gas flow path 2a inside the cell unit 1 (refer to Figure 1A ). The fuel gas supplied to the gas tank 16 is supplied by a reformer 102 (refer to Figure 4) Generation.

[0064] The hydrogen-rich fuel gas can be generated by subjecting the raw fuel to steam reforming or the like. When the fuel gas is generated by steam reforming, the fuel gas contains steam.

[0065] In Figure 2A the example shown in FIG., the battery cell stack device 10 includes two rows of battery cell stacks 11, two support bodies 15, and a gas tank 16. Each of the two rows of battery cell stacks 11 has a plurality of battery cells 1. Each battery cell stack 11 is fixed to each support body 15. The gas tank 16 has two through holes on its upper surface. Each support body 15 is disposed in each through hole. The internal space 22 is formed by one gas tank 16 and two support bodies 15. In Figure 2A FIG., the battery cell stack device 10 having two rows of battery cell stacks 11 is shown, but the battery cell stack device may have one row of battery cell stacks 11, or may have three or more rows of battery cell stacks 11.

[0066] The shape of the insertion hole 15a is, for example, an oval shape in plan view. The insertion hole 15a may be such that the length in the thickness direction T, which is the arrangement direction of the battery cells 1, is larger than the distance between the two end collector members 17 located at both ends of the battery cell stack 11. The width of the insertion hole 15a may be larger than the length in the width direction W of the battery cell 1 (see Figure 1A ).

[0067] As Figure 2B shown in FIG., a fixing member 13 is filled and solidified at the joint between the inner wall of the insertion hole 15a and the lower end portion of the battery cell 1. Thus, the inner wall of the insertion hole 15a is joined and fixed to the lower end portions of the plurality of battery cells 1, respectively, and the lower end portions of the battery cells 1 are joined and fixed to each other. The gas flow path 2a of each battery cell 1 communicates with the internal space 22 of the support member 14 at the lower end portion.

[0068] The fixing member 13 and the joining member 21 may be made of a member having low conductivity such as glass. As specific materials for the fixing member 13 and the joining member 21, amorphous glass or the like can be used, and in particular, crystallized glass or the like can be used.

[0069] As the crystallized glass, for example, SiO 2 -CaO-based, MgO-B 2 O 3 -based, La 2 O 3 -B 2 O 3 -MgO-based, La 2 O 3 -B 2 O 3 -ZnO-based, SiO 2Any one of materials such as -CaO-ZnO system, and in particular, SiO can also be used. 2 -MgO system materials.

[0070] In addition, as Figure 2B shown, a conductive member 18 is interposed between adjacent battery cells 1 in the plurality of battery cells 1. The conductive member 18 electrically connects the fuel electrode layer 5 of one adjacent battery cell 1 and the air electrode layer 8 of the other battery cell 1 in series. More specifically, the conductive member 18 connects the interconnect 4 electrically connected to the fuel electrode layer 5 of one adjacent battery cell 1 and the air electrode layer 8 of the other battery cell 1. It should be noted that when the interconnect 4 is made of metal or alloy, the interconnect 4 and the conductive member 18 can be integrated, and the conductive member 18 can also serve as the interconnect 4.

[0071] In addition, as Figure 2B shown, the end collector member 17 is electrically connected to the outermost battery cell 1 in the arrangement direction of the plurality of battery cells 1. The end collector member 17 is connected to the conductive portion 19 protruding to the outside of the battery cell stack 11. The conductive portion 19 collects the electricity generated by the power generation of the battery cell 1 and leads it out to the outside. It should be noted that in Figure 2A , the illustration of the end collector member 17 is omitted.

[0072] In addition, as Figure 2C shown, the battery cell stack device 10 serially connects two battery cell stacks 11A and 11B and functions as one battery. Therefore, the conductive portion 19 of the battery cell stack device 10 is divided into a positive terminal 19A, a negative terminal 19B, and a connection terminal 19C.

[0073] The positive terminal 19A is the positive electrode when the electricity generated by the battery cell stack 11 is output to the outside, and is electrically connected to the end collector member 17 on the positive electrode side in the battery cell stack 11A. The negative terminal 19B is the negative electrode when the electricity generated by the battery cell stack 11 is output to the outside, and is electrically connected to the end collector member 17 on the negative electrode side in the battery cell stack 11B.

[0074] The connection terminal 19C electrically connects the end collector member 17 on the negative electrode side in the battery cell stack 11A and the end collector member 17 on the positive electrode side in the battery cell stack 11B.

[0075] <Details of the fuel electrode layer>

[0076] Next, with reference to Figure 3A the details of the fuel electrode layer 5 as the first electrode in the first embodiment will be described. Figure 3A is an enlarged cross-sectional view of the region R1 shown in Figure 1A .

[0077] As shown Figure 3A in FIG. 2, the fuel electrode layer 5 has a first surface 5A and a second surface 5B. The first surface 5A is located at a position in contact with the solid electrolyte layer 6. The second surface 5B is located on the side opposite to the first surface 5A. The second surface 5B is located at a position in contact with the support substrate 2. The thickness of the fuel electrode layer 5 can be, for example, 40 μm or less, and further can be 30 μm or less.

[0078] The fuel electrode layer 5 contains rare earth elements. The fuel electrode layer 5 may also contain, for example, CeO in which Y, La, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Yb, etc. are dissolved 2 . The fuel electrode layer 5 may also contain, for example, BaMO in which rare earth elements such as Sc, Y, La, Nd, Sm, Gd, Dy, Yb, etc. are dissolved 3 , SrMO 3 (where M is Zr and / or Ce) and other perovskite-type compounds.

[0079] The fuel electrode layer 5 may contain, for example, a zirconia-based compound or a perovskite-type compound. The fuel electrode layer 5 may also contain, for example, Yb-containing stabilized zirconia. The fuel electrode layer 5 may also contain, for example, BaZrO in which rare earth elements such as Sc, Y, La, Nd, Sm, Gd, Dy, Yb, etc. are dissolved 3 , SrZrO 3 and other perovskite-type compounds.

[0080] The content rate of rare earth elements on the second surface 5B side of the fuel electrode layer 5 is larger than that on the first surface 5A side. The fuel electrode layer 5 contains, for example, 5 atomic % to 60 atomic % of rare earth elements. The first surface 5A side of the fuel electrode layer 5 contains, for example, 5 atomic % to 30 atomic % of rare earth elements. The second surface 5B side of the fuel electrode layer 5 contains, for example, 10 atomic % to 60 atomic % of rare earth elements. It should be noted that the content rate (atomic %) of rare earth elements in the fuel electrode layer 5 shown here is a ratio with the total amount of elements constituting the oxide having ionic conductivity (wherein, including dissolved rare earth elements, excluding oxygen) as the denominator and the amount of rare earth elements as the numerator. Hereinafter, the oxide having ionic conductivity will be simply referred to as ionic conductive oxide. It should be noted that in the case where a plurality of rare earth elements are dissolved in the ionic conductive oxide, it is only necessary to compare the total content rates of the plurality of rare earth elements.

[0081] Thus, on the second surface 5B side of the fuel electrode layer 5, by making the content rate of rare earth elements larger than that on the first surface 5A side, the power generation performance of the battery cell 1 can be improved. For example, on the second surface 5B side far from the solid electrolyte layer 6, the content rate of rare earth elements is relatively high, thereby promoting H generated in the fuel electrode layer 5 during power generation 2On the other hand, on the side of the first surface 5A close to the solid electrolyte layer 6, the content rate of the rare earth element is relatively low, thereby promoting the reaction in the fuel electrode layer 5 during power generation. Therefore, for the battery cell 1 according to the present embodiment, the power generation performance is improved.

[0082] As the main reason for improving the power generation performance of the battery cell 1 by making the content rate of the rare earth element different between the second surface 5B side and the first surface 5A side of the fuel electrode layer 5, it is considered that due to the solid solution amount of the rare earth element, the amount of oxygen vacancies contained in the ion-conductive oxide in which the rare earth element is solid-solved changes. On the first surface 5A side, the content rate of the rare earth element, that is, the rare earth element solid-solved in the ion-conductive oxide is relatively small, and the amount of oxygen vacancies contained in the ion-conductive oxide is relatively small. Therefore, the ion-conductive oxide on the first surface 5A side has relatively high ion conductivity, and the supply amount of oxide ions increases near the solid electrolyte layer 6. As a result, the oxidation reaction of hydrogen is promoted, and a large amount of H 2 O is generated. On the other hand, on the second surface 5B side, the content rate of the rare earth element, that is, the rare earth element solid-solved in the ion-conductive oxide is relatively large, and the amount of oxygen vacancies contained in the ion-conductive oxide is relatively large. Therefore, the H 2 O generated from the fuel electrode layer 5 is easily attracted to the oxygen vacancies on the second surface 5B side and moves. As a result, H 2 O is easily discharged to the outside of the fuel electrode layer 5, and it is difficult to cause a bad situation where the voids inside the fuel electrode layer 5 are blocked by H 2 O. In this way, by promoting the oxidation reaction of hydrogen and the discharge of the generated H 2 O at the same time, the power generation performance of the battery cell 1 is improved. In particular, during power generation under conditions where the utilization rate of the fuel gas is relatively high, the influence on the improvement of the power generation performance of the battery cell 1 becomes significant.

[0083] Here, the content rate of the rare earth element in the fuel electrode layer 5 can be confirmed, for example, by elemental analysis using EPMA. Specifically, for example, the cross-section in the stacking direction of the element part 3 is mirror-polished, and a semi-quantitative analysis is performed on one or more rare earth elements for a specified area of the fuel electrode layer 5 including the first surface 5A and a specified area of the fuel electrode layer 5 including the second surface 5B. For the first surface 5A side and the second surface 5B side, the content rate of the rare earth element per unit area is calculated respectively, and by converting them into atomic% units respectively, their magnitudes can be compared. At this time, for example, the region within 20% of the average thickness of the fuel electrode layer 5 from the first surface 5A can be set as the first surface 5A side, and the region within 20% of the average thickness of the fuel electrode layer 5 from the second surface 5B can be set as the second surface 5B side, and the content rates of the rare earth elements in each region can be compared. In addition, the content rate of the rare earth element can be measured in any plurality of cross-sections of the fuel electrode layer 5, and their average values can be compared.

[0084] The content rate of the rare earth element in the fuel electrode layer 5 can gradually increase from the first surface 5A toward the second surface 5B. Thereby, the power generation performance of the battery cell 1 is further improved.

[0085] In addition, the fuel electrode layer 5 may also contain a plurality of rare earth elements. The fuel electrode layer 5 may also contain a first rare earth element and a second rare earth element. The first rare earth element may be, for example, Yb. The second rare earth element may be, for example, Y.

[0086] The fuel electrode layer 5 may also contain a first ion-conductive material in which a rare earth element is dissolved. The first material in which the first rare earth element is dissolved has higher ion conductivity than the first material in which the second rare earth element is dissolved. By the fuel electrode layer 5 containing the first materials having different ion conductivities, an improvement in the ion conductivity in the fuel electrode layer 5 can be expected.

[0087] In addition, when the fuel electrode layer 5 contains the above-described first rare earth element and second rare earth element, in the fuel electrode layer 5, the content rate of the first rare earth element may be larger on the first surface 5A side than on the second surface 5B side. Thereby, the power generation performance of the battery cell 1 is improved.

[0088] In addition, when the fuel electrode layer 5 contains the above-described first rare earth element and second rare earth element, in the first surface 5A of the solid electrolyte layer 6 and the fuel electrode layer 5, the content rate of the first rare earth element may be larger than the content rate of the second rare earth element. Thereby, the power generation performance of the battery cell 1 is improved.

[0089] Figure 3B is an enlarged cross-sectional view showing another example of the electrochemical battery cell of the first embodiment. As Figure 3B shown, the fuel electrode layer 5 may also have a portion 5a located between the first surface 5A and the second surface 5B. The content rate of the first rare earth element in the portion 5a may be greater than that of the first surface 5A. Thereby, in the electrochemically active reaction region in the fuel electrode layer 5, the oxidation reaction of hydrogen can be further promoted.

[0090] It should be noted that in Figure 3B , the portion 5a is located in a part closer to the second surface 5B than the first surface 5A of the fuel electrode layer 5, but may also be located in a part closer to the first surface 5A than the second surface 5B, or may be located in the middle part between the first surface 5A and the second surface 5B. In addition, there may also be a part where the portion 5a is not located between the first surface 5A and the second surface 5B.

[0091] The support substrate 2 is located on the second surface 5B. The support substrate 2 can also be a ceramic support body that supports the fuel electrode layer 5. The support substrate 2 can also contain an oxide of a rare earth element contained in the fuel electrode layer 5 or a first material in which a rare earth element is solid-solved and contained in the solid electrolyte layer 6. Thus, element diffusion between the fuel electrode layer 5 and the support substrate 2 is reduced, and a decrease in the conductivity of the fuel electrode layer 5 and the hydrogen oxidation reaction can be suppressed.

[0092] In addition, the support substrate 2 can also contain an oxide of a second rare earth element. Thus, growth of particles of the rare earth oxide can be suppressed, and the strength of the support substrate can be improved.

[0093] <Module>

[0094] Next, Figure 4 The module of the present embodiment using the above-described electrochemical cell unit device will be described. Figure 4 is an external perspective view showing the module of the first embodiment. In Figure 4 it shows a state where the front surface and the rear surface, which are parts of the storage container 101, are removed, and the cell stack device 10 of the fuel cell stored inside is taken out rearward.

[0095] As Figure 4 shown, the module 100 includes a storage container 101 and a cell stack device 10 stored in the storage container 101. In addition, a reformer 102 is disposed above the cell stack device 10.

[0096] The reformer 102 reforms a raw fuel such as natural gas or kerosene to generate a fuel gas and supplies it to the cell unit 1. The raw fuel is supplied to the reformer 102 through the raw fuel supply pipe 103. It should be noted that the reformer 102 can also include a vaporization unit 102a that vaporizes water and a reforming unit 102b. The reforming unit 102b includes a reforming catalyst (not shown) and reforms the raw fuel into a fuel gas. Such a reformer 102 can perform steam reforming, which is an efficient reforming reaction.

[0097] Then, the fuel gas generated by the reformer 102 is supplied to the gas flow path 2a of the cell unit 1 (refer to Figure 1A ) through the gas flow pipe 20, the gas tank 16, and the support member 14.

[0098] In addition, in the module 100 having the above-described structure, with the combustion of the gas and the power generation of the cell unit 1, the temperature inside the module 100 during normal power generation becomes about 500°C to 1000°C.

[0099] In such a module 100, as described above, by including the cell stack device 10 that improves the power generation performance, a module 100 that improves the power generation performance can be formed.

[0100] <Module housing device>

[0101] Figure 5 It is an exploded perspective view showing an example of the module housing device of the first embodiment. The module housing device 110 of the present embodiment includes an outer housing 111, Figure 4 the module 100 shown in the figure, and auxiliary equipment (not shown). The auxiliary equipment operates the module 100. The module 100 and the auxiliary equipment are housed inside the outer housing 111. It should be noted that, Figure 5 a part of the structure is omitted in the figure.

[0102] Figure 5 The outer housing 111 of the module housing device 110 shown in the figure has a support column 112 and an outer plate 113. A partition plate 114 divides the inside of the outer housing 111 into upper and lower parts. The space above the partition plate 114 inside the outer housing 111 is a module housing chamber 115 for housing the module 100, and the space below the partition plate 114 inside the outer housing 111 is an auxiliary equipment housing chamber 116 for housing the auxiliary equipment that operates the module 100. It should be noted that, Figure 5 the auxiliary equipment housed in the auxiliary equipment housing chamber 116 is omitted in the figure.

[0103] In addition, the partition plate 114 has an air circulation port 117 for allowing the air in the auxiliary equipment housing chamber 116 to flow toward the module housing chamber 115 side. The outer plate 113 constituting the module housing chamber 115 has an exhaust port 118 for discharging the air inside the module housing chamber 115.

[0104] In such a module housing device 110, as described above, by including the module 100 that improves the power generation performance in the module housing chamber 115, a module housing device 110 with improved power generation performance can be formed.

[0105] It should be noted that, in the above embodiment, the case of using a hollow flat support substrate is exemplified, but it can also be applied to a battery cell stack device using a cylindrical support substrate.

[0106] [Second Embodiment]

[0107] Next, with reference to Figures 6 - 8 the electrochemical cell and the electrochemical cell device of the second embodiment will be described.

[0108] In the above-described embodiment, the so-called "longitudinal stripe type" in which only one element portion including a fuel electrode layer, a solid electrolyte layer, and an air electrode layer is provided on the surface of the support substrate is illustrated. However, it can be applied to a so-called "transverse stripe type" electrochemical cell unit device of a transverse stripe type electrochemical cell unit in which element portions are provided at mutually separated positions on the surface of the support substrate and adjacent element portions are arranged and electrically connected to each other.

[0109] Figure 6 It is a cross-sectional view of the electrochemical cell unit device of the second embodiment. Figure 7 It is a cross-sectional view showing an example of the electrochemical cell unit of the second embodiment.

[0110] As Figure 6 shown, in the cell unit stack device 10A of the second embodiment, a plurality of cell units 1A extend in the longitudinal direction L from a pipe 22a through which fuel gas flows. The cell unit 1A has a plurality of element portions 3 on the support substrate 2. A gas flow path 2a through which fuel gas from the pipe 22a flows is provided inside the support substrate 2.

[0111] In addition, the respective cell units 1A are electrically connected to each other via a connection member 31. The connection member 31 is located between the element portions 3 respectively provided in the respective cell units 1A and connects adjacent cell units 1A. Specifically, the connection member 31 electrically joins an interconnector 4 that connects the air electrode layer 8 of one cell unit 1A and the fuel electrode layer 5 of another adjacent cell unit 1A.

[0112] In addition, as Figure 7 shown, the cell unit 1A includes a support substrate 2, a pair of element portions 3, and a sealing portion 30. The support substrate 2 is columnar and has a pair of opposing flat surfaces, i.e., a first surface n1 and a second surface n2, and a pair of arcuate side surfaces m connecting the first surface n1 and the second surface n2.

[0113] A pair of element portions 3 are located on the first surface n1 and the second surface n2 of the support substrate 2 so as to face each other. In addition, the sealing portion 30 is located at a position covering the side surface m of the support substrate 2.

[0114] The cell unit 1A has a shape that is symmetric with respect to a plane passing through the center in the thickness direction T and parallel to the first surface n1 and the second surface n2 of the support substrate 2. The element portion 3 has a fuel electrode layer 5, a solid electrolyte layer 6, an intermediate layer 7, and an air electrode layer 8.

[0115] Figure 8 It is a cross-sectional view of the enlarged region R2 shown in Figure 7 As Figure 8As shown, the fuel electrode layer 5 has a first surface 5A and a second surface 5B. The first surface 5A is located at a position in contact with the solid electrolyte layer 6. The second surface 5B is located on the side opposite to the first surface 5A. The second surface 5B is located at a position in contact with the support substrate 2.

[0116] The solid electrolyte layer 6 contains a first material having ion conductivity in which a rare earth element is dissolved. The fuel electrode layer 5 contains a rare earth element. The content rate of the rare earth element is higher on the second surface 5B side of the fuel electrode layer 5 than on the first surface 5A side. Thereby, the power generation performance of the battery cell 1A can be improved. For example, on the second surface 5B side far from the solid electrolyte layer 6, the content rate of the rare earth element is relatively high, thereby promoting the discharge of H 2 O generated in the fuel electrode layer 5 during power generation. On the other hand, on the first surface 5A side close to the solid electrolyte layer 6, the content rate of the rare earth element is relatively low, thereby promoting the reaction in the fuel electrode layer 5 during power generation. Therefore, according to the battery cell 1A of the present embodiment, the power generation performance is improved.

[0117] [Third Embodiment]

[0118] Figure 9A is a perspective view showing an example of an electrochemical battery cell of the third embodiment. Figure 9B is Figure 9A a partial cross-sectional view of the electrochemical battery cell shown.

[0119] As Figure 9A shown, the battery cell 1B has an element portion 3B in which a fuel electrode layer 5, a solid electrolyte layer 6, and an air electrode layer 8 are laminated. The element portion 3B is a portion where the solid electrolyte layer 6 is sandwiched between the fuel electrode layer 5 and the air electrode layer 8. The element portion 3B may have an intermediate layer located between the solid electrolyte layer 6 and the air electrode layer 8. In an electrochemical battery cell device in which a plurality of flat battery cells are laminated, for example, a plurality of battery cells 1B are electrically connected by conductive members 91 and 92 which are adjacent metal layers. The conductive members 91 and 92 have a gas flow path that electrically connects adjacent battery cells 1B to each other and supplies gas to the fuel electrode layer 5 or the air electrode layer 8.

[0120] As Figure 9B shown, there is a seal that hermetically seals the fuel gas flow path 98 and the oxygen-containing gas flow path 97 of the flat battery cell stack. The seal is a fixing member 96 of the battery cell and has a joining member 93 and support members 94 and 95 as a frame. The joining member 93 may be glass or a metal material such as silver solder.

[0121] The support member 94 can also be a so-called partition plate that divides the flow path 98 of the fuel gas and the flow path 97 of the oxygen-containing gas. The materials of the support members 94 and 95 can be, for example, conductive metals or insulating ceramics. The support members 94 and 95 can also be made of insulating materials for both or either of them. When the support member 94 is made of metal, the support member 94 can be integrated with the conductive member 92. When the support member 95 is made of metal, the support member 95 can be integrated with the conductive member 91.

[0122] Any one of the joining member 93 and the support members 94 and 95 is insulating, electrically insulating the two conductive members 91 and 92 sandwiching the flat battery cell.

[0123] Figure 9C It is Figure 9B An enlarged cross-sectional view of the area R3 shown. As Figure 9C shown, the fuel electrode layer 5 has a first surface 5A and a second surface 5B. The first surface 5A is located at the position in contact with the solid electrolyte layer 6. The second surface 5B is located on the side opposite to the first surface 5A. The second surface 5B is located at the position in contact with the conductive member 91.

[0124] The solid electrolyte layer 6 contains a first material with ion conductivity in which rare earth elements are dissolved. The fuel electrode layer 5 contains rare earth elements. The content rate of rare earth elements on the second surface 5B side of the fuel electrode layer 5 is larger than that on the first surface 5A side. Thereby, the power generation performance of the battery cell 1B can be improved. For example, on the second surface 5B side far from the solid electrolyte layer 6, the content rate of rare earth elements is relatively high, thereby promoting the discharge of H 2 O generated in the fuel electrode layer 5 during power generation. On the other hand, on the first surface 5A side close to the solid electrolyte layer 6, the content rate of rare earth elements is relatively low, thereby promoting the reaction in the fuel electrode layer 5 during power generation. Therefore, according to the battery 1B of the present embodiment, the power generation performance is improved.

[0125] [Fourth Embodiment]

[0126] Figure 10A It is a cross-sectional view showing an example of the electrochemical battery cell of the fourth embodiment. Figure 10B , Figure 10C It is a cross-sectional view showing another example of the electrochemical battery cell of the fourth embodiment. Figure 11 It is Figure 10A An enlarged view of the area R4 shown. It should be noted that Figure 11 can also be applied to Figure 10B , Figure 10C example.

[0127] As Figures 10A - 10CAs shown, the battery cell 1C has an element portion 3C in which a fuel electrode layer 5, a solid electrolyte layer 6, an intermediate layer 7, and an air electrode layer 8 are stacked, and a support substrate 2. The support substrate 2 has through-holes or fine holes at the portion in contact with the element portion 3C, and has a member 120 located outside the gas flow path 2a. The support substrate 2 enables gas to flow between the gas flow path 2a and the element portion 3C. The support substrate 2 may also be composed of one or more metal plates, for example. The material of the metal plate may contain chromium. The metal plate may have a conductive covering layer. The support substrate 2 electrically connects adjacent battery cells 1C to each other. The element portion 3C may be directly formed on the support substrate 2 or may be joined to the support substrate 2 through a joining member.

[0128] In Figure 10A the example shown, the side surface of the fuel electrode layer 5 is covered by the solid electrolyte layer 6, and the gas flow path 2a through which the fuel gas flows is hermetically sealed. As Figure 10B shown, the side surface of the fuel electrode layer 5 may also be covered and sealed by a dense seal 9 containing glass or ceramic. The seal 9 covering the side surface of the fuel electrode layer 5 may also have electrical insulation properties.

[0129] In addition, as Figure 10C shown, the gas flow path 2a of the support substrate 2 may also be formed by a member 120 having unevenness.

[0130] Figure 11 is a cross-sectional view of the enlarged region R4 shown in Figure 10A . As Figure 11 shown, the fuel electrode layer 5 has a first surface 5A and a second surface 5B. The first surface 5A is located at the position in contact with the solid electrolyte layer 6. The second surface 5B is located on the side opposite to the first surface 5A. The second surface 5B is located at the position in contact with the support substrate 2.

[0131] The solid electrolyte layer 6 contains a first material having ion conductivity in which rare earth elements are dissolved. The fuel electrode layer 5 contains rare earth elements. The content rate of rare earth elements on the second surface 5B side of the fuel electrode layer 5 is larger than that on the first surface 5A side. Thereby, the power generation performance of the battery cell 1C can be improved. For example, on the second surface 5B side far from the solid electrolyte layer 6, the content rate of rare earth elements is relatively high, thereby promoting the discharge of H 2 O generated in the fuel electrode layer 5 during power generation. On the other hand, on the first surface 5A side close to the solid electrolyte layer 6, the content rate of rare earth elements is relatively low, thereby promoting the reaction in the fuel electrode layer 5 during power generation. Therefore, according to the battery cell 1C of the present embodiment, the power generation performance is improved.

[0132] [Other Embodiments]

[0133] Next, an electrochemical battery cell device of other embodiments will be described.

[0134] In the above-described embodiments, as an example of the "electrochemical cell unit", "electrochemical cell unit device", "module", and "module housing device", a fuel cell unit, a fuel cell unit stack device, a fuel cell module, and a fuel cell device are shown. However, as other examples, they may be an electrolytic cell unit, an electrolytic cell unit stack device, an electrolytic module, and an electrolytic device, respectively. The electrolytic cell unit has a first electrode and a second electrode, and decomposes water vapor into hydrogen and oxygen, or decomposes carbon dioxide into carbon monoxide and oxygen by supplying electric power.

[0135] According to such an electrolytic cell unit, an electrolytic cell unit stack device, an electrolytic module, and an electrolytic device, since the content rate of the rare earth element is higher on the second surface side of the first electrode than on the first surface side, the electrolysis performance of the electrochemical cell unit can be improved. For example, on the second surface side far from the solid electrolyte layer, the content rate of the rare earth element is relatively high, thereby promoting the supply of H 2 O into the first electrode. On the other hand, on the first surface side close to the solid electrolyte layer, the content rate of the rare earth element is relatively low, thereby promoting the reaction in the first electrode during electrolysis. Therefore, according to the electrochemical cell unit of the present embodiment, the electrolysis performance is improved. In particular, during electrolysis under the condition where the supply amount of H 2 O is relatively high, the influence on the improvement of the electrolysis performance of the electrochemical cell unit becomes significant.

[0136] As described above, the present disclosure has been described in detail. However, the present disclosure is not limited to the above-described embodiments, and various changes, improvements, etc. can be made without departing from the gist of the present disclosure.

[0137] In one embodiment, (1) the electrochemical cell unit includes:

[0138] a solid electrolyte layer containing a first material having ion conductivity in which a rare earth element is dissolved; and

[0139] a first electrode containing a rare earth element and having a first surface in contact with the solid electrolyte layer and a second surface opposite to the first surface,

[0140] wherein the content rate of the rare earth element on the second surface side of the first electrode is larger than that on the first surface side.

[0141] (2) Based on the electrochemical cell unit in the above (1), it may also be that

[0142] the content rate of the rare earth element in the first electrode gradually increases from the first surface toward the second surface.

[0143] (3) Based on the electrochemical cell unit in the above (1) or (2), it may also be that

[0144] The first electrode contains a first rare earth element and a second rare earth element,

[0145] The content rate of the first rare earth element is greater on the first surface side than on the second surface side of the first electrode.

[0146] (4) Based on the electrochemical cell unit in the above (3), it can also be that

[0147] The electrochemical cell unit has a portion located between the first surface and the second surface and having a content rate of the first rare earth element greater than that of the first surface.

[0148] (5) Based on the electrochemical cell unit in the above (1) to (4), it can also be that the rare earth elements contained in the first electrode include a first rare earth element and a second rare earth element, and in the solid electrolyte layer and the first surface, the content rate of the first rare earth element is greater than that of the second rare earth element.

[0149] (6) Based on the electrochemical cell unit in the above (1) to (5), it can also be that

[0150] The electrochemical cell unit includes a ceramic support, which contains an oxide of the rare earth element contained in the first electrode or the first material in which the rare earth element is solid-solved and contained in the solid electrolyte layer, and is located on the second surface.

[0151] (7) Based on the electrochemical cell unit in the above (3) to (5), it can also be that

[0152] The electrochemical cell unit includes a ceramic support, which contains an oxide of the second rare earth element and is located on the second surface.

[0153] In one embodiment, (8) the electrochemical cell unit device has a cell unit stack including the electrochemical cell unit according to any one of the above (1) to (7).

[0154] In one embodiment, (9) the module includes the electrochemical cell unit device according to the above (8) and a storage container for storing the electrochemical cell unit device.

[0155] In one embodiment, (10) the module housing device includes:

[0156] The module according to the above (9);

[0157] Ancillary equipment for operating the module; and

[0158] An outer housing for housing the module and the ancillary equipment.

[0159] The embodiments disclosed herein should be considered illustrative in all respects and not restrictive. In fact, the above embodiments can be implemented in various ways. Additionally, the above embodiments can be omitted, replaced, or changed in various ways without departing from the appended technical solutions and their gist.

[0160] Description of reference numerals:

[0161] 1, 1A, 1B, 1C Battery cells

[0162] 2 Support substrate

[0163] 3, 3B, 3C Element parts

[0164] 4 Interconnector

[0165] 5 Fuel electrode layer

[0166] 6 Solid electrolyte layer

[0167] 7 Intermediate layer

[0168] 8 Air electrode layer

[0169] 10, 10A Battery cell stack device

[0170] 11 Battery cell stack

[0171] 12 Fixing member

[0172] 13 Fastening piece

[0173] 14 Supporting member

[0174] 15 Support

[0175] 16 Gas tank

[0176] 17 End collector member

[0177] 18 Conductive member

[0178] 100 Module

[0179] 110 Module housing device.

Claims

1. An electrochemical cell unit, wherein, the electrochemical cell unit includes: a solid electrolyte layer containing a first ion-conductive material in which a rare earth element is dissolved; and a first electrode containing a rare earth element, having a first surface in contact with the solid electrolyte layer and a second surface on the side opposite to the first surface, wherein the content rate of the rare earth element on the second surface side of the first electrode is greater than that on the first surface side.

2. The electrochemical cell unit according to claim 1, wherein, the content rate of the rare earth element in the first electrode gradually increases from the first surface toward the second surface.

3. The electrochemical cell unit according to claim 1 or 2, wherein, the first electrode contains a first rare earth element and a second rare earth element, and the content rate of the first rare earth element is greater on the first surface side than on the second surface side of the first electrode.

4. The electrochemical cell unit according to claim 3, wherein, the electrochemical cell unit has a portion between the first surface and the second surface where the content rate of the first rare earth element is greater than that of the first surface.

5. The electrochemical cell unit according to any one of claims 1 to 4, wherein, the rare earth element contained in the first electrode includes a first rare earth element and a second rare earth element, and in the solid electrolyte layer and the first surface, the content rate of the first rare earth element is greater than that of the second rare earth element.

6. The electrochemical cell unit according to any one of claims 1 to 5, wherein, the electrochemical cell unit includes a ceramic support, the ceramic support contains an oxide of the rare earth element contained in the first electrode or the first material in which the rare earth element is dissolved in the solid electrolyte layer, and is located on the second surface.

7. The electrochemical cell unit according to any one of claims 3 to 5, wherein, the electrochemical cell unit includes a ceramic support, the ceramic support contains an oxide of the second rare earth element, and is located on the second surface.

8. An electrochemical cell unit device, wherein, the electrochemical cell unit device has a cell unit stack including the electrochemical cell unit according to any one of claims 1 to 7.

9. A module, wherein, the module includes: the electrochemical cell unit device according to claim 8; and a storage container for storing the electrochemical cell unit device.

10. A module housing device, wherein, the module housing device includes: the module according to claim 9; auxiliary equipment for operating the module; and an outer housing for housing the module and the auxiliary equipment.

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