Solid state electrochemical device

Abstract

Provided is a solid-state electrochemical device comprising: a solid-state electrolyte having a first main surface and a second main surface facing the first main surface; a first electrode having a third main surface and a fourth main surface facing the third main surface, the first electrode being provided such that the third main surface faces the first main surface; a first current collector having a fifth main surface and a sixth main surface facing the fifth main surface, the first current collector being provided such that the fifth main surface faces the fourth main surface; and a first connector having a seventh main surface, the first connector being provided so that the seventh main surface faces the sixth main surface, the seventh main surface of the first connector being a flat surface, the first current collector comprising a first metal porous body having a three-dimensional network structure, and the second current collector comprising a second metal porous body having a three-dimensional network structure. A plurality of first through-holes extending in a first direction from the fifth main surface to the sixth main surface are formed in the fifth main surface.

Description

Technical Field

[0001] The present invention relates to a solid-state electrochemical device. This application claims priority based on Japanese Application No. 2023-001579 filed on January 10, 2023, and incorporates by reference all the disclosures in the above-mentioned Japanese application. Background Art

[0002] Conventionally, a solid-state electrochemical device has been used, which includes: a solid electrolyte having a first major surface and a second major surface opposite to the first major surface; a first electrode having a third major surface and a fourth major surface opposite to the third major surface, and arranged such that the third major surface faces the first major surface; a first current collector having a fifth major surface and a sixth major surface opposite to the fifth major surface, and arranged such that the fifth major surface faces the fourth major surface; and a first interconnector having a seventh major surface, and arranged such that the seventh major surface faces the sixth major surface (Patent Document 1).

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: International Publication No. 2021 / 210231. Summary of the Invention

[0006] A solid-state electrochemical device according to one aspect of the present invention includes:

[0007] a solid electrolyte having a first major surface and a second major surface opposite to the first major surface;

[0008] a first electrode having a third major surface and a fourth major surface opposite to the third major surface, and arranged such that the third major surface faces the first major surface;

[0009] a first current collector having a fifth major surface and a sixth major surface opposite to the fifth major surface, and arranged such that the fifth major surface faces the fourth major surface; and

[0010] a first interconnector having a seventh major surface, and arranged such that the seventh major surface faces the sixth major surface,

[0011] the seventh major surface of the first interconnector is a flat surface,

[0012] the first current collector is composed of a first metal porous body having a three-dimensional network structure,

[0013] a plurality of first through-holes extending in a first direction from the fifth major surface to the sixth major surface are formed on the fifth major surface. Brief Description of the Drawings

[0014] Figure 1 It is a schematic cross-sectional view showing an example of a solid-state electrochemical device according to one aspect of the present invention.

[0015] Figure 2 It is a schematic view showing an example of a first current collector according to one aspect of the present invention as viewed from above. Detailed Description

[0016] [Problems to be Solved by the Present Invention]

[0017] Conventionally, in a solid-state electrochemical device, a connector with groove processing has been used in combination with a current collector composed of a metal porous body having a three-dimensional network structure. Therefore, due to the grooves of the connector, it has been difficult to cause "voltage drop" in the solid-state electrochemical device, and fuel gas or air has become easy to diffuse in the current collector.

[0018] In recent years, miniaturization of solid-state electrochemical devices has been required. For example, as a method for miniaturizing a solid-state electrochemical device, it is conceivable to use a connector that has been thinned by making the main surface groove-free and flat. However, if such a thinned connector is used in combination with a current collector, in a solid-state electrochemical device, sometimes the "voltage drop" increases, and due to the reduced diffusibility of gas, the "power density" of the solid-state electrochemical device tends to decrease. Therefore, it has sometimes been difficult to "miniaturize" the solid-state electrochemical device and suppress the "voltage drop" and the decrease in "power density".

[0019] Therefore, an object of the present invention is to provide a solid-state electrochemical device that is small, has excellent suppression of "voltage drop", and has excellent "power density".

[0020] [Effects of the Present Invention]

[0021] According to the present invention, it is possible to provide a solid-state electrochemical device that is small, has excellent suppression of "voltage drop", and has excellent "power density".

[0022] [Description of Embodiments of the Present Invention]

[0023] First, embodiments of the present invention will be listed and described.

[0024] [1] A solid-state electrochemical device according to one aspect of the present invention includes:

[0025] A solid electrolyte having a first main surface and a second main surface opposite to the first main surface;

[0026] A first electrode having a third main surface and a fourth main surface opposite to the third main surface, and disposed such that the third main surface faces the first main surface;

[0027] A first fluid collector having a fifth main surface and a sixth main surface opposite to the fifth main surface, and disposed such that the fifth main surface faces the fourth main surface; and

[0028] A first connector having a seventh main surface and disposed such that the seventh main surface faces the sixth main surface,

[0029] The seventh main surface of the first connector is a flat surface,

[0030] The first fluid collector is composed of a first metal porous body having a three-dimensional network structure,

[0031] A plurality of first through-holes extending along a first direction from the fifth main surface to the sixth main surface are formed in the fifth main surface.

[0032] According to the present invention, a solid-state electrochemical device that is small, has excellent suppression of "pressure drop", and has excellent "power density" can be provided.

[0033] [2] In the above [1], when looking down on the fifth main surface, the first through-hole has a first width along a second direction orthogonal to the first direction, and has a second width along a third direction orthogonal to the first direction and the second direction,

[0034] The average value of the first width and the second width may be 2 mm or more and 20 mm or less. Thereby, a solid-state electrochemical device with more excellent suppression of "pressure drop" and more excellent "power density" can be provided.

[0035] [3] In the above [1] or [2], the percentage of the total area of the first through-holes with respect to the area of the fifth main surface, that is, the first opening ratio, may be 2.0% or more and 35% or less. Thereby, a solid-state electrochemical device with more excellent suppression of "pressure drop" and more excellent "power density" can be provided.

[0036] [4] In any one of the above [1] to [3], in each of the nine first regions set by equally dividing the fifth main surface on an area basis, the percentage of the total area of the first through-holes in the first region with respect to the area of the first region, that is, the second opening ratio, may be 2.0% or more and 35% or less. Thereby, a solid-state electrochemical device with more excellent suppression of "pressure drop" and more excellent "power density" can be provided.

[0037] [5] In any one of the above [1] to [4], the first metal porous body may be a nickel-cobalt metal porous body. Thereby, a solid-state electrochemical device with more excellent "power density" can be provided.

[0038] [6] In any one of the above [1] to [4], the first metal porous body may be a nickel metal porous body. Thereby, a solid-state electrochemical device having more excellent "power density" can be provided.

[0039] [7] In any one of the above [1] to [4], the first metal porous body may be a nickel-tin metal porous body. Thereby, a solid-state electrochemical device having more excellent "power density" can be provided.

[0040] [8] In any one of the above [1] to [7], the solid-state electrochemical device further has:

[0041] A second electrode having an eighth major surface and a ninth major surface opposite to the eighth major surface, and arranged such that the eighth major surface faces the second major surface;

[0042] A second current collector having a tenth major surface and an eleventh major surface opposite to the tenth major surface, and arranged such that the tenth major surface faces the ninth major surface; and

[0043] A second connector having a twelfth major surface, and arranged such that the twelfth major surface faces the eleventh major surface,

[0044] The twelfth major surface of the second connector is a flat surface,

[0045] The second current collector is composed of a second metal porous body having a three-dimensional network structure,

[0046] A plurality of second through-holes extending along a fourth direction from the tenth major surface to the eleventh major surface may be formed on the tenth major surface. Thereby, a solid-state electrochemical device that is smaller in size, more excellent in suppressing "pressure drop", and has more excellent "power density" can be provided.

[0047] [9] In the above [8], when looking down at the tenth major surface, the second through-hole has a third width along a fifth direction orthogonal to the fourth direction, and has a fourth width along a sixth direction orthogonal to the fourth direction and the fifth direction,

[0048] The average value of the third width and the fourth width may be 2 mm or more and 20 mm or less. Thereby, a solid-state electrochemical device that is more excellent in suppressing "pressure drop" and has more excellent "power density" can be provided.

[0049]

[10] In the above [8] or [9], the percentage of the total area of the second through-holes with respect to the area of the tenth major surface, that is, the third opening ratio, may be 2.0% or more and 35% or less. Thereby, a solid-state electrochemical device that is more excellent in suppressing "pressure drop" and has more excellent "power density" can be provided.

[0050]

[11] In any one of the above [8] to

[10] , in each of the nine second regions set by dividing the above-mentioned tenth main surface into nine equal parts on an area basis, the percentage of the total area of the above-mentioned second through holes in the above-mentioned second region with respect to the area of the above-mentioned second region, that is, the fourth opening ratio, may be 2.0% or more and 35% or less. Thereby, a solid-state electrochemical device with more excellent suppression of "pressure drop" and more excellent "power density" can be provided.

[0051]

[12] In any one of the above [8] to

[11] , the above-mentioned second metal porous body may be a nickel-cobalt metal porous body. Thereby, a solid-state electrochemical device with more excellent "power density" can be provided.

[0052]

[13] In any one of the above [8] to

[11] , the above-mentioned second metal porous body may be a nickel metal porous body. Thereby, a solid-state electrochemical device with more excellent "power density" can be provided.

[0053]

[14] In any one of the above [8] to

[11] , the above-mentioned second metal porous body may be a nickel-tin metal porous body. Thereby, a solid-state electrochemical device with more excellent "power density" can be provided.

[0054] [Specific content of the embodiment of the present invention]

[0055] Hereinafter, a specific example of a solid-state electrochemical device according to an embodiment of the present invention (hereinafter also referred to as "this embodiment") will be described with reference to the drawings. In the drawings of the present invention, the same reference numerals denote the same or corresponding parts. In addition, the dimensional relationships such as length, width, thickness, and depth have been appropriately changed for the clarity and simplicity of the drawings, and do not necessarily represent the actual dimensional relationships.

[0056] In this specification, an expression in the form of "A to B" means the upper and lower limits of the range (that is, A or more and B or less). When no unit is described in A and only a unit is described in B, the unit of A is the same as the unit of B.

[0057] [Embodiment 1: Solid-state electrochemical device]

[0058] Use Figure 1 To describe a cutting tool according to an embodiment of the present invention. Figure 1 Is a schematic cross-sectional view showing an example of a solid-state electrochemical device according to one aspect of the present invention.

[0059] A solid-state electrochemical device 100 according to an embodiment of the present invention (hereinafter also referred to as "Embodiment 1") includes:

[0060] A solid electrolyte 11 having a first major surface 111 and a second major surface 112 opposite to the first major surface 111;

[0061] A first electrode 12 having a third major surface 121 and a fourth major surface 122 opposite to the third major surface 121, and arranged such that the third major surface 121 faces the first major surface 111;

[0062] A first current collector 20 having a fifth major surface 201 and a sixth major surface 202 opposite to the fifth major surface 201, and arranged such that the fifth major surface 201 faces the fourth major surface 122; and

[0063] A first connector 40 having a seventh major surface 401, and arranged such that the seventh major surface 401 faces the sixth major surface 202,

[0064] The seventh major surface 401 of the first connector 40 is a flat surface,

[0065] The first current collector 20 is made of a first metal porous body having a three-dimensional network structure,

[0066] A plurality of first through-holes 21 extending in a first direction from the fifth major surface 201 to the sixth major surface 202 are formed in the fifth major surface.

[0067] According to the present invention, a solid-state electrochemical device that is small-sized, excellent in suppressing "voltage drop", and has excellent "power density" can be provided. The reasons are speculated as follows.

[0068] (a) The seventh major surface 401 of the first connector 40 is a flat surface. Thus, the first connector 40 can be thinned, and therefore the entire solid-state electrochemical device 100 can be miniaturized.

[0069] (b) As described above, by making the seventh major surface 401 of the first connector 40 a flat surface, the entire solid-state electrochemical device 100 can be miniaturized. However, when the seventh major surface 401 of the first connector 40 is a flat surface (in other words, there are no grooves on the seventh major surface of the first connector 40), "voltage drop" of the solid-state electrochemical device 100 is likely to occur. In addition, in the current collector, the diffusibility of the fuel gas (hydrogen) and air is likely to decrease, and the reactivity of the fuel gas (hydrogen) and the reactivity of air are likely to decrease. Therefore, there is a tendency for the power density of the solid-state electrochemical device 100 to decrease.

[0070] In the first current collector 20 of the solid-state electrochemical device 100 according to the present embodiment, a plurality of first through holes 21 extending in a first direction from the fifth main surface 201 to the sixth main surface 202 are formed in the fifth main surface 201. Thereby, an increase in "voltage drop" is suppressed. In addition, the gas (fuel gas or air) flowing into the solid-state electrochemical device 100 from the first connector 40 side easily diffuses in the first current collector 20, and a decrease in the "diffusibility" of the fuel gas or air can be suppressed, and a decrease in the power density of the solid-state electrochemical device 100 can be suppressed.

[0071] That is, according to the present invention, a solid-state electrochemical device 100 that is small-sized, excellent in suppressing "voltage drop", and has excellent "power density" can be provided.

[0072] <<Solid-state Electrochemical Device>>

[0073] In the present invention, the solid-state electrochemical device 100 refers to a concept including both a solid oxide fuel cell (SOFC) and a solid oxide electrolytic cell (SOEC). In addition, in the present invention, the solid-state electrochemical device 100 can be understood as being sheet-shaped and having a thirteenth main surface 101 and a fourteenth main surface 102.

[0074] The thickness of the solid-state electrochemical device 100 can be 2.1 mm or less. Here, the thickness of the solid-state electrochemical device 100 refers to the distance between the thirteenth main surface 101 and the fourteenth main surface 102. Thereby, a small-sized solid-state electrochemical device 100 can be provided. The upper limit of the thickness of the solid-state electrochemical device 100 can be 1.8 mm or 1.5 mm. The lower limit of the thickness of the solid-state electrochemical device 100 is not particularly limited, and from the viewpoint of manufacturing, it can be 1 mm, 0.75 mm, or 0.5 mm.

[0075] The thickness of the solid-state electrochemical device 100 can be determined by the same method as the measurement method of the "thickness of the first current collector 20" described later.

[0076] <<Solid-State Electrolyte>>

[0077] The solid-state electrochemical device 100 of the present invention has a solid-state electrolyte 11, and the solid-state electrolyte 11 has a first main surface 111 and a second main surface 112 opposite to the first main surface 111. For example, the solid-state electrolyte 11 is formed of yttria-stabilized zirconia (YSZ).

[0078] The thickness of the solid electrolyte 11 can be 0.0005 mm or more and 0.05 mm or less. If the thickness of the solid electrolyte 11 is less than 0.0005 mm, there is a tendency that it is difficult to exhibit the function of the solid electrolyte 11 in the solid-state electrochemical device 100. If the thickness of the solid electrolyte 11 is greater than 0.05 mm, there is a tendency that it is difficult to miniaturize the solid-state electrochemical device 100. The thickness of the solid electrolyte 11 can be determined by the same method as the measurement method of the "thickness of the first current collector 20" described later.

[0079] <<First Electrode>>

[0080] The solid-state electrochemical device 100 of the present invention includes a first electrode 12. The first electrode 12 has a third main surface 121 and a fourth main surface 122 opposite to the third main surface 121, and is disposed such that the third main surface 121 faces the first main surface 111. The first electrode 12 can be a cathode or an anode. However, when the first electrode 12 is a cathode, the second electrode 13 described later is an anode, and when the first electrode 12 is an anode, the second electrode 13 described later is a cathode. When the first electrode 12 is a cathode, the first electrode 12 can be formed of, for example, LSC (oxide of lanthanum (La), strontium (Sr), and cobalt (Co)). When the first electrode 12 is an anode, it can be formed of a composite of, for example, YSZ and nickel oxide (Ni2O).

[0081] The thickness of the first electrode 12 can be 0.1 mm or more and 0.5 mm or less. If the thickness of the first electrode 12 is less than 0.1 mm, there is a tendency that it is difficult to exhibit the function of the electrode in the solid-state electrochemical device 100. If the thickness of the first electrode 12 is greater than 0.5 mm, there is a tendency that it is difficult to miniaturize the solid-state electrochemical device 100. The thickness of the first electrode 12 can be determined by the same method as the measurement method of the "thickness of the first current collector 20" described later.

[0082] <<First Current Collector>>

[0083] The solid-state electrochemical device 100 of the present invention has a first current collector 20. The first current collector 20 has a fifth main surface 201 and a sixth main surface 202 opposite to the fifth main surface 201, and is arranged such that the fifth main surface 201 faces the fourth main surface 122. Regarding the first current collector 20, except for the aspects described below, the descriptions in paragraphs

[0036] to

[0047] , paragraphs

[0080] to

[0084] , paragraph

[0086] , paragraph

[0087] , and paragraphs

[0112] to

[0114] of International Publication No. 2021 / 153406 are incorporated herein by reference. However, in the present invention, the description with the gist of "bubbles are easily released to the outside" in the description is replaced with "the diffusivity of gas is easily improved and the pressure drop is easily suppressed". In the present invention, the "metal porous sheet" in the description is replaced with the "first current collector". In the present invention, the "hole" in the description is replaced with the "first through-hole". In the present invention, the "first main surface" in the description is replaced with the "fifth main surface", and the "second main surface" is replaced with the "sixth main surface". In the present invention, the "width W1" in the description is replaced with the "first width", and the "width W2" is replaced with the "second width". In the present invention, the "opening ratio" in the description is replaced with the "first opening ratio".

[0084] The thickness of the first current collector 20 can be 0.05 mm or more and 0.5 mm or less. If the thickness of the first current collector 20 is less than 0.05 mm, there is a tendency that it is difficult to function as a current collector in the solid-state electrochemical device 100. If the thickness of the first current collector 20 is greater than 0.5 mm, there is a tendency that it is difficult to miniaturize the solid-state electrochemical device 100. The thickness of the first current collector 20 can be measured by a commercially available digital display thickness gauge (Teclock Co., Ltd.).

[0085] <First through-hole>

[0086] In the solid-state electrochemical device 100 of the present invention, a plurality of first through-holes 21 extending along a first direction from the fifth main surface 201 to the sixth main surface 202 are formed in the fifth main surface 201. Thus, in the solid-state electrochemical device 100, "pressure drop" can be suppressed and "power density" can be improved.

[0087] As Figure 2As shown, when looking down at the fifth main surface 201, the first through-hole 21 has a first width 211 in a second direction orthogonal to the first direction and a second width 212 in a third direction orthogonal to the first direction and the second direction. The average value of the first width 211 and the second width 212 can be 2 mm or more and 20 mm or less. Additionally, the second direction is the direction in which the first width 211 becomes the largest. Thereby, it is possible to further suppress the increase in pressure drop and further suppress the decrease in power density. The lower limit of the average value of the first width 211 and the second width 212 can be 2 mm, can be 4 mm, or can be 5 mm. The upper limit of the average value of the first width 211 and the second width 212 can be 20 mm, can be 15 mm, or can be 10 mm. The average value of the first width 211 and the second width 212 can be 4 mm or more and 15 mm or less, or can be 5 mm or more and 10 mm or less.

[0088] In the solid-state electrochemical device 100, the average value of the first width 211 and the second width 212 can be obtained by the following method. That is, when looking down at the fifth main surface 201 of the first current collector 20, the first width 211 and the second width 212 are measured for any one of the first through-holes 21. Next, a value obtained by dividing the sum of the first width 211 and the second width 212 by 2 is calculated. Next, for any of the other four first through-holes 21, values are obtained by the same method. By calculating the average value of these values, the average value of the first width 211 and the second width 212 can be obtained.

[0089] In the fifth main surface 201, the first opening ratio based on the first through-hole 21 can be 2.0% or more and 35% or less. Here, the first opening ratio is the percentage of the total area S1 of the first through-holes 21 with respect to the area S2 of the fifth main surface 201. Thereby, it is possible to further suppress the increase in pressure drop and further suppress the decrease in power density. The lower limit of the first opening ratio based on the first through-hole 21 can be 2.0%, can be 5%, or can be 10%. The upper limit of the first opening ratio based on the first through-hole 21 can be 35%, can be 30%, or can be 25%. The first opening ratio based on the first through-hole 21 can be 5% or more and 30% or less, or can be 10% or more and 25% or less.

[0090] In the first fluid collector 20, the area S1 of the first through hole 21 and the area S2 of the fifth main surface 201 can be determined by the following method. First, by photographing the fifth main surface 201 of the first fluid collector 20 from the first direction, image data of the fifth main surface 201 of the first fluid collector 20 is obtained. Next, by performing binarization processing on the image data, the region where the first through hole 21 is formed and the other regions are determined. Then, by measuring the area of the region where the first through hole 21 is formed, the area S1 of the first through hole 21 can be obtained. In addition, by measuring the area of the region combining the "region where the first through hole 21 is formed" and the "other regions", the area S2 of the fifth main surface 201 can be obtained.

[0091] In each of the nine first regions 203 set by equally dividing the fifth main surface 201 based on area, the second opening ratio based on the first through hole 21 can be 2.0% or more and 35% or less. Here, the second opening ratio is the percentage of the total area S1 of the first through holes 21 in the first region 203 with respect to the area S3 of the first region 203. Thereby, an increase in pressure drop can be further suppressed and a decrease in power density can be further suppressed. In each of the nine first regions 203, the second opening ratio based on the first through hole 21 can be 2.0% or more, can be 5% or more, or can be 10% or more. In each of the nine first regions 203, the second opening ratio based on the first through hole 21 can be 35% or less, can be 30% or less, or can be 25% or less. In each of the nine first regions 203, the second opening ratio based on the first through hole 21 can be 5% or more and 30% or less, or can be 10% or more and 25% or less.

[0092] In the first fluid collector 20, except for setting the first region 203 by equally dividing the image data of the fifth main surface 201 of the first fluid collector 20 based on area, the area S3 of the first region 203 can be determined by the same method as the area S2 of the fifth main surface 201. In addition, when the first through hole 21 is located at a position straddling multiple first regions 203, only the area of the part located within the first region 203 is measured.

[0093] In the first fluid collector 20, the plurality of first through holes 21 can be arranged in multiple rows along the second direction. The plurality of first through holes 21 included in each row of the multiple rows can be periodically arranged at a first interval in the second direction. Each row of the multiple rows can also be periodically arranged at a second interval in the third direction.

[0094] <First metal porous body>

[0095] The first current collector 20 is composed of a first metal porous body having a three-dimensional network structure. The first metal porous body refers to a porous body in which the main component of the skeleton contains a metal element. Here, "the main component of the skeleton contains a metal element" means that the total content of the metal element in the main body of the skeleton is greater than 50% by mass.

[0096] In the main body of the skeleton, the "total content of the metal element" can be obtained through the following steps. First, determine the part where the skeleton extends to obtain an observation image of an electron microscope (SEM) of a cross-section perpendicular to the extending direction of the skeleton. Then, perform analysis using the EDX device attached to the SEM. As the SEM, for example, the product named "SUPRA35VP" manufactured by Carl Zeiss Microscopy Co., Ltd. is used. As the EDX device, for example, the product named "octanesuper" manufactured by AMETEK, Inc. is used. Based on the atomic concentration of each element detected by the EDX device, the mass percentage of each metal element in the main body of the skeleton is obtained respectively. Then, by summing up the "mass percentage of each metal element in the main body of the skeleton", the "total content of the metal element" in the main body of the skeleton can be obtained.

[0097] It has been confirmed that in the same first current collector 20, as long as the measurement is carried out by the above method, even if the measurement area is arbitrarily changed, there is no deviation in the measurement result.

[0098] The first metal porous body can be a nickel-cobalt metal porous body. Thereby, the decrease in power density can be further suppressed. The nickel-cobalt metal porous body refers to a porous body in which the main component of the skeleton contains nickel element and cobalt element. Here, "the main component of the skeleton contains nickel element and cobalt element" means that both nickel element and cobalt element are contained in the main body of the skeleton, and the total content of nickel element and cobalt element is greater than 50% by mass.

[0099] The first metal porous body can be a nickel metal porous body. Thereby, the decrease in power density can be further suppressed. The nickel metal porous body refers to a porous body in which the main component of the skeleton contains nickel element. Here, "the main component of the skeleton contains nickel element" means that the total content of nickel element in the main body of the skeleton is greater than 50% by mass.

[0100] The first metal porous body can be a nickel-tin metal porous body. Thereby, the decrease in power density can be further suppressed. The nickel-tin metal porous body refers to a porous body in which the main component of the skeleton contains nickel element and tin element. Here, "the main component of the skeleton contains nickel element and tin element" means that both nickel element and tin element are contained in the main body of the skeleton, and the total content of nickel element and tin element is greater than 50% by mass.

[0101] The average pore diameter of the first metal porous body is not particularly limited and can be, for example, 100 μm or more and 1000 μm or less, 200 μm or more and 900 μm or less, 400 μm or more and 800 μm or less. Regarding the average pore diameter, the content described in International Publication No. 2021 / 153406 is incorporated herein by reference.

[0102] <<First Connector>>

[0103] The solid-state electrochemical device 100 of the present invention includes a first connector 40. The first connector 40 has a seventh main surface 401 and is arranged such that the seventh main surface 401 faces the sixth main surface 202. In addition, the seventh main surface 401 of the first connector 40 is a flat surface. Here, "the seventh main surface 401 is a flat surface" means that "no groove is formed on the seventh main surface 401". Thereby, the first connector 40 can be thinned, and the solid-state electrochemical device 100 can be miniaturized. For example, the first connector 40 is formed of an iron-chromium (FeCr) alloy.

[0104] The thickness of the first connector 40 can be 0.1 mm or more and 0.4 mm or less. If the thickness of the first connector 40 is less than 0.1 mm, there is a tendency that it is difficult to exhibit the function as a connector in the solid-state electrochemical device 100. If the first connector 40 is greater than 0.4 mm, there is a tendency that it is difficult to miniaturize the solid-state electrochemical device 100. The thickness of the first connector 40 can be determined by the same method as the measurement method of the "thickness of the first current collector 20" described above.

[0105] <<Second Electrode>>

[0106] The solid-state electrochemical device 100 of the present invention preferably further includes a second electrode 13. The second electrode 13 has an eighth main surface 131 and a ninth main surface 132 opposite to the eighth main surface 131, and is arranged such that the eighth main surface 131 faces the second main surface 112. When the second electrode 13 is a cathode, the second electrode 13 can be formed of, for example, LSC (oxide of lanthanum (La), strontium (Sr), and cobalt (Co)). When the second electrode 13 is an anode, it can be formed of a composite of, for example, YSZ and nickel oxide (Ni2O).

[0107] The thickness of the second electrode 13 can be 0.1 mm or more and 0.5 mm or less. If the thickness of the second electrode 13 is less than 0.1 mm, there is a tendency that it is difficult to exhibit the function as an electrode in the solid-state electrochemical device 100. If the thickness of the second electrode 13 is greater than 0.5 mm, there is a tendency that it is difficult to miniaturize the solid-state electrochemical device 100. The thickness of the second electrode 13 can be determined by the same method as the measurement method of the "thickness of the first current collector 20" described above.

[0108] <<Second current collector>>

[0109] The solid-state electrochemical device 100 of the present invention may further include a second current collector 30. The second current collector 30 has a tenth main surface 301 and an eleventh main surface 302 opposite to the tenth main surface 301, and is arranged such that the tenth main surface 301 faces the ninth main surface 132. Regarding the second current collector 30, except for the aspects described below, the descriptions in paragraphs

[0036] to

[0047] , paragraphs

[0080] to

[0084] , paragraph

[0086] , paragraph

[0087] , and paragraphs

[0112] to

[0114] of International Publication No. 2021 / 153406 are incorporated herein by reference. However, in the present invention, the description with the gist of "bubbles are easily released to the outside" in the description is replaced with "the diffusivity of gas is easily increased and the pressure drop is easily suppressed". In the present invention, the "metal porous sheet" in the description is replaced with "second current collector". In the present invention, the "hole" in the description is replaced with "second through-hole". In the present invention, the "first main surface" in the description is replaced with "tenth main surface", and the "second main surface" is replaced with "eleventh main surface". In the present invention, the "first direction" in the description is replaced with "fourth direction", the "second direction" is replaced with "fifth direction", and the "third direction" is replaced with "sixth direction". In the present invention, the "width W1" in the description is replaced with "third width", and the "width W2" is replaced with "fourth width". In the present invention, the "opening ratio" in the description is replaced with "third opening ratio".

[0110] The thickness of the second current collector 30 may be 0.05 mm or more and 0.5 mm or less. If the thickness of the second current collector 30 is less than 0.05 mm, there is a tendency that it is difficult to function as a current collector in the solid-state electrochemical device 100. If the thickness of the second current collector 30 is greater than 0.5 mm, there is a tendency that it is difficult to miniaturize the solid-state electrochemical device 100. The thickness of the second current collector 30 can be determined by the same method as the method for measuring the "thickness of the first current collector 20" described above.

[0111] <Second through-hole>

[0112] In the solid-state electrochemical device 100 of the present invention, a plurality of second through-holes 31 extending in the fourth direction from the tenth main surface 301 to the eleventh main surface 302 may or may not be formed on the tenth main surface 301. In the solid-state electrochemical device 100 of the present invention, a plurality of second through-holes 31 extending in the fourth direction from the tenth main surface 301 to the eleventh main surface 302 may be formed on the tenth main surface 301. Thereby, an increase in the pressure drop can be further suppressed and a decrease in the power density can be further suppressed.

[0113] When looking down at the tenth main surface, the second through-hole 31 has a third width 311 along a fifth direction orthogonal to the fourth direction, and has a fourth width along a sixth direction orthogonal to the fourth direction and the fifth direction. The average value of the third width 311 and the fourth width can be 2 mm or more and 20 mm or less. In addition, the fifth direction is the direction in which the third width 311 becomes the largest. Thereby, an increase in the pressure drop can be further suppressed and a decrease in the power density can be further suppressed. The lower limit of the average value of the third width 311 and the fourth width can be 2 mm, can be 4 mm, or can be 5 mm. The upper limit of the average value of the third width 311 and the fourth width can be 20 mm, can be 15 mm, or can be 10 mm. The average value of the third width 311 and the fourth width can be 4 mm or more and 15 mm or less, or can be 5 mm or more and 10 mm or less.

[0114] In the solid-state electrochemical device 100, the average value of the third width 311 and the fourth width can be obtained by the following method. That is, when looking down at the tenth main surface 301 of the second current collector 30, the third width 311 and the fourth width are measured for any one of the second through-holes 31. Next, a value obtained by dividing the sum of the third width 311 and the fourth width by 2 is calculated. Next, for any other four second through-holes 31, values are obtained by the same method. By calculating the average value of these values, the average value of the third width 311 and the fourth width can be obtained.

[0115] In the tenth main surface 301, the third opening ratio based on the second through-hole 31 can be 2.0% or more and 35% or less. Here, the third opening ratio is the percentage of the total area S4 of the second through-holes 31 with respect to the area S5 of the tenth main surface 301. Thereby, an increase in the pressure drop can be further suppressed and a decrease in the power density can be further suppressed. The lower limit of the third opening ratio based on the second through-hole 31 can be 2.0%, can be 5.0%, or can be 10%. The upper limit of the third opening ratio based on the second through-hole 31 can be 35%, can be 30%, or can be 25%. The third opening ratio based on the second through-hole 31 can be 5% or more and 30% or less, or can be 10% or more and 25% or less.

[0116] In the second fluid collector 30, the area S4 of the second through-hole 31 and the area S5 of the tenth main surface 301 can be determined by the following method. First, by photographing the tenth main surface 301 of the first fluid collector 20 from the fourth direction, image data of the tenth main surface 301 of the second fluid collector 30 is obtained. Next, by performing binarization processing on the image data, the region where the second through-hole 31 is formed and the other regions are determined. Then, by measuring the area of the region where the second through-hole 31 is formed, the area S4 of the second through-hole 31 can be obtained. In addition, by measuring the area of the region combining the region where the "second through-hole 31 is formed" and the "other regions", the area S5 of the tenth main surface 301 can be obtained.

[0117] In each of the nine second regions set by equally dividing the tenth main surface 301 based on area, the fourth opening ratio based on the second through-hole 31 can be 2.0% or more and 35% or less. Here, the fourth opening ratio is the percentage of the total area S4 of the second through-holes 31 in the second region with respect to the area S6 of the second region. Thereby, an increase in pressure drop can be further suppressed and a decrease in power density can be further suppressed. In each of the nine second regions, the fourth opening ratio based on the second through-hole 31 can be 2.0% or more, can be 5% or more, or can be 10% or more. In each of the nine second regions, the fourth opening ratio based on the second through-hole 31 can be 35% or less, can be 30% or less, or can be 25% or less. In each of the nine second regions, the fourth opening ratio based on the second through-hole 31 can be 5% or more and 30% or less, or can be 10% or more and 25% or less.

[0118] In the second fluid collector 30, except for setting the second regions by equally dividing the image data of the tenth main surface 301 of the second fluid collector 30 based on area, the area S6 of the second region can be determined by the same method as the area S5 of the tenth main surface 301. In addition, when the first through-hole 21 is located at a position straddling multiple second regions, only the area of the portion located within the second region is measured.

[0119] In the second fluid collector 30, a plurality of second through-holes 31 can be arranged in multiple rows along the fifth direction. The plurality of second through-holes 31 included in each row of the multiple rows can be periodically arranged at a third interval in the fifth direction. Each row of the multiple rows can be periodically arranged at a fourth interval in the sixth direction.

[0120] <Second metal porous body>

[0121] The second fluid collector 30 can be constituted by a second metal porous body having a three-dimensional network structure.

[0122] The second metal porous body refers to a porous body in which the main component of the framework contains a metal element. Here, "the main component of the framework contains a metal element" means that the total content of the metal element in the main component of the framework is greater than 50% by mass. In addition, in the main component of the framework, the "total content of the metal element" can be obtained by the same steps as the measurement of the "total content of the metal element" in the above-mentioned "first metal porous body".

[0123] It was confirmed that in the same second current collector 30, as long as the measurement is carried out by the above method, even if the measurement area is arbitrarily changed, there is no deviation in the measurement result.

[0124] The second metal porous body can be a nickel-cobalt metal porous body. Thereby, a further reduction in power density can be suppressed. In addition, here, the definition of the nickel-cobalt metal porous body is the same as that of the nickel-cobalt metal porous body of the first metal porous body.

[0125] The second metal porous body can be a nickel metal porous body. Thereby, a further reduction in power density can be suppressed. In addition, here, the definition of the nickel metal porous body is the same as that of the nickel metal porous body of the first metal porous body.

[0126] The second metal porous body can be a nickel-tin metal porous body. Thereby, a further reduction in power density can be suppressed. In addition, here, the definition of the nickel-tin metal porous body is the same as that of the nickel-tin metal porous body of the first metal porous body.

[0127] The average pore diameter of the second metal porous body is not particularly limited and can be, for example, 100 μm or more and 1000 μm or less, 200 μm or more and 900 μm or less, 400 μm or more and 800 μm or less. Regarding the average pore diameter, the content described in International Publication No. 2021 / 153406 is incorporated herein by reference.

[0128] <<Second Connector>>

[0129] The solid-state electrochemical device 100 of the present invention may further include a second connector 50, and the second connector 50 has a twelfth main surface 501 and is disposed such that the twelfth main surface 501 faces the eleventh main surface 302.

[0130] For example, the second connector 50 is formed of an iron-chromium (FeCr) alloy. In addition, the twelfth main surface of the second connector 50 may be a flat surface or may not be a flat surface. Here, "the twelfth main surface 501 is a flat surface" means that "no groove is formed in the twelfth main surface 501". The twelfth main surface 501 of the second connector 50 may be a flat surface. Thereby, the solid-state electrochemical device 100 can be further miniaturized.

[0131] The thickness of the second connector 50 may be 0.1 mm or more and 0.4 mm or less. If the thickness of the second connector 50 is less than 0.1 mm, there is a tendency that it is difficult to function as a connector in the solid-state electrochemical device 100. If the thickness of the second connector 50 is greater than 0.4 mm, there is a tendency that it is difficult to miniaturize the solid-state electrochemical device 100. The thickness of the second connector 50 can be determined by the same method as the measurement method of the "thickness of the first current collector 20" described above.

[0132] <<Battery Cell>>

[0133] In the present invention, a structure composed of a solid electrolyte 11, a first electrode 12, and a second electrode 13 is defined as a battery cell. The thickness of the battery cell may be 0.2005 mm or more and 1.05 mm or less. If the thickness of the battery cell is less than 0.2005 mm, there is a tendency that it is difficult to function as a battery cell in the solid-state electrochemical device 100. If the thickness of the battery cell is greater than 1.05 mm, there is a tendency that it is difficult to miniaturize the solid-state electrochemical device 100. The lower limit of the thickness of the battery cell may be 0.25 mm, may be 0.3 mm, or may be 0.35 mm. The upper limit of the thickness of the battery cell may be 0.9 mm, may be 0.8 mm, or may be 0.7 mm. The thickness of the battery cell may be 0.3 mm or more and 0.8 mm or less, or may be 0.35 mm or more and 0.7 mm or less.

[0134] In the solid-state electrochemical device 100, the thickness of the battery cell can be obtained by calculating the sum of the "thickness of the solid electrolyte 11", the "thickness of the first electrode 12", and the "thickness of the second electrode 13".

[0135] <<Manufacturing Method of Solid-State Electrochemical Device>>

[0136] The solid-state electrochemical device 100 of the present embodiment can be manufactured by appropriately using a known method.

[0137] Examples

[0138] Hereinafter, specific descriptions will be given based on the examples of the present invention, but the present invention is not limited to the following examples.

[0139] <<Manufacture of Solid-State Electrochemical Device>>

[0140] First, in order to fabricate the solid-state electrochemical devices of Specimens 1 to 12, Specimen 101, and Specimen 102, prepare the first connector described in Table 1, the first current collector described in Table 1, the first electrode described in Table 1, the solid electrolyte described in Table 1, the second electrode described in Table 1, the second current collector described in Table 1, and the second connector described in Table 1. The planar dimensions of each of the first connector, the first current collector, the first electrode, the solid electrolyte, the second electrode, the second current collector, and the second connector are all 100 mm × 100 mm. In addition, the description such as "FeCr" in the "Composition" column of the "First Connector" column in Table 1 means that the first connector of the specimen is formed of an iron-chromium (FeCr) alloy. Further, the description such as "NiCo" in the "Composition" column of the "First Current Collector" column in Table 1 means that the first current collector of the specimen is composed of a nickel-cobalt (NiCo) metal porous body. Further, the description such as "LSC" in the "Composition" column of the "First Electrode" column in Table 1 means that the first electrode of the specimen is formed of LSC (an oxide of lanthanum (La), strontium (Sr), and cobalt (Co)). Further, the description such as "YSZ" in the "Composition" column of the "Solid Electrolyte" column in Table 1 means that the solid electrolyte of the specimen is formed of yttria-stabilized zirconia (YSZ). Further, the description such as "Ni+YSZ" in the "Composition" column of the "Second Electrode" column in Table 1 means that the second electrode of the specimen is formed of a composite of YSZ and nickel oxide (Ni2O). Further, the description such as "Ni" in the "Composition" column of the "Second Current Collector" column in Table 1 means that the second current collector of the specimen is composed of a nickel metal porous body. Further, the description such as "FeCr" in the "Composition" column of the "Second Connector" column in Table 1 means that the second connector of the specimen is formed of an iron-chromium (FeCr) alloy.

[0141] Next, except for the aspect of combining the first connector described in Table 1, the first current collector described in Table 1, the first electrode described in Table 1, the solid electrolyte described in Table 1, the second electrode described in Table 1, the second current collector described in Table 1, and the second connector described in Table 1, fabricate the solid-state electrochemical devices of Specimens 1 to 12, Specimen 101, and Specimen 102 by using a known method.

[0142] [Table 1]

[0143]

[0144] <<Characteristic Evaluation of Solid-State Electrochemical Device>>

[0145] <<Thickness of Battery Cell>>

[0146] For the solid-state electrochemical devices of each sample, the thickness of the battery cell was determined by the method described in Embodiment 1. The obtained results were entered in the column of "Thickness of battery cell [mm]" in Table 1.

[0147] <Thickness of solid-state electrochemical device>

[0148] For the solid-state electrochemical devices of each sample, the thickness of the solid-state electrochemical device was determined by the method described in Embodiment 1. The obtained results were entered in the column of "Thickness of solid-state electrochemical device [mm]" in Table 1. Here, "Thickness of solid-state electrochemical device [mm]" being 2.10 mm or less means that the solid-state electrochemical device is small-sized. Table 1 shows that the solid-state electrochemical devices of Samples 1 to 12 and Sample 102 are extremely small-sized compared to the solid-state electrochemical device of Sample 101.

[0149] <Pressure drop>

[0150] For the solid-state electrochemical devices of each sample, with the degree of pressure drop of the solid-state electrochemical device of Sample 102 taken as 100, the degree of pressure drop of the solid-state electrochemical devices of Samples 1 to 12 and 101 was determined by the following method. That is, air gas was circulated at a condition of 0.5 L / minute from the center of the first current collector, and a digital display differential pressure gauge testo512 of Testo Co., Ltd. was used to measure the pressure at the center when the air gas circulated radially from the center. With the degree of pressure drop corresponding to the pressure of Sample 102 taken as 100, the degree of pressure drop corresponding to the pressure of each sample was determined as a relative value. The obtained results were entered in the column of "Pressure drop" in Table 1. In addition, with the degree of pressure drop of the solid-state electrochemical device of Sample 102 taken as 100, a degree of pressure drop of less than 100 for the solid-state electrochemical device of each sample means excellent suppression of the pressure drop of the solid-state electrochemical device. Table 1 shows that the solid-state electrochemical devices of Samples 1 to 12 are extremely excellent in suppressing the pressure drop compared to the solid-state electrochemical device of Sample 102.

[0151] <Maximum power density of solid-state electrochemical device and maximum power density per unit thickness>

[0152] The working temperature was set at 750 °C, hydrogen was circulated as a fuel gas at a condition of 0.2 L / minute at the anode of the solid-state electrochemical device of each sample, and air was circulated at a condition of 0.3 L / minute at the cathode to obtain the maximum power density. In addition, for the solid-state electrochemical device of each sample, the first current collector was used as the cathode and the second current collector was used as the anode. The obtained results were entered in the column of "Maximum power density [mW / cm 2 " in Table 1.

[0153] Next, for each solid-state electrochemical device of the specimens, the maximum power density per unit thickness of the solid-state electrochemical device was obtained by dividing the maximum power density of the solid-state electrochemical device by the thickness of the solid-state electrochemical device. The results obtained were entered in the column of "Maximum power density per unit thickness [mW / cm 2 / mm]" in Table 1.

[0154] Here, when the maximum power density is "100 mW / cm 2 or more" and the maximum power density per unit thickness is "50 mW / cm 2 / mm or more", it means that the power density of the solid-state electrochemical device is excellent.

[0155] If the power densities of the solid-state electrochemical devices of Specimens 1 to 12 and Specimen 102 that can be miniaturized are compared, the solid-state electrochemical devices of Specimens 1 to 12 have an extremely excellent maximum power density and an extremely excellent maximum power density per unit thickness compared to the solid-state electrochemical device of Specimen 102. That is, the solid-state electrochemical devices of Specimens 1 to 12 can have an extremely excellent power density compared to the solid-state electrochemical device of Specimen 102.

[0156] From the above, it can be seen that the solid-state electrochemical devices of Specimens 1 to 12 are small, have excellent suppression of "voltage drop", and have excellent "power density".

[0157] In addition, all of the above specimens used the first current collector as the air electrode current collector, but it is presumed that the same effect would be obtained even if the first current collector was used as the fuel electrode current collector instead of the air electrode current collector. This is because it is considered common technical knowledge for those skilled in the art that if the power density is increased by improving the diffusibility of the air flowing in from the air electrode side, the power density will also be increased by improving the diffusibility of the hydrogen flowing in from the fuel electrode side.

[0158] The embodiments and examples of the present invention have been described as above, but it was also initially planned to appropriately combine the configurations of the above-described embodiments and examples.

[0159] The embodiments disclosed this time should be considered illustrative in all respects and not restrictive. The scope of the present invention is shown by the claims rather than by the above embodiments, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0160] Description of Reference Numerals

[0161] 11: Solid electrolyte,

[0162] 111: First main surface,

[0163] 112: Second main surface,

[0164] 12: The first electrode,

[0165] 121: The third main surface,

[0166] 122: The fourth main surface,

[0167] 13: The second electrode,

[0168] 131: The eighth main surface,

[0169] 132: The ninth main surface,

[0170] 20: The first current collector,

[0171] 201: The fifth main surface,

[0172] 202: The sixth main surface,

[0173] 203: The first region,

[0174] 21: The first through-hole,

[0175] 211: The first width,

[0176] 212: The second width,

[0177] 30: The second current collector,

[0178] 301: The tenth main surface,

[0179] 302: The eleventh main surface,

[0180] 31: The second through-hole,

[0181] 311: The third width,

[0182] 40: The first connector,

[0183] 401: The seventh main surface,

[0184] 50: The second connector,

[0185] 501: The twelfth main surface,

[0186] 100: The solid-state electrochemical device,

[0187] 101: The thirteenth main surface,

[0188] 102: The fourteenth main surface.

Claims

1. A solid-state electrochemical device having: A solid electrolyte having a first major surface and a second major surface opposite to the first major surface; A first electrode having a third major surface and a fourth major surface opposite to the third major surface, and arranged such that the third major surface faces the first major surface; A first current collector having a fifth major surface and a sixth major surface opposite to the fifth major surface, and arranged such that the fifth major surface faces the fourth major surface; And A first connector having a seventh major surface, and arranged such that the seventh major surface faces the sixth major surface, The seventh major surface of the first connector is a flat surface, The first current collector is composed of a first metal porous body having a three-dimensional network structure, A plurality of first through-holes extending along a first direction from the fifth major surface to the sixth major surface are formed on the fifth major surface.

2. The solid state electrochemical device according to claim 1, wherein, When looking down at the fifth major surface, the first through-holes have a first width along a second direction orthogonal to the first direction, and a second width along a third direction orthogonal to the first direction and the second direction, The average value of the first width and the second width is 2 mm or more and 20 mm or less.

3. The solid state electrochemical device according to claim 1 or 2, wherein The percentage of the total area of the first through-holes relative to the area of the fifth major surface, that is, the first opening ratio, is 2.0% or more and 35% or less.

4. The solid-state electrochemical device according to any one of claims 1 to 3, wherein, In each of the nine first regions set by equally dividing the fifth major surface on an area basis, the percentage of the total area of the first through-holes in the first region relative to the area of the first region, that is, the second opening ratio, is 2.0% or more and 35% or less.

5. The solid-state electrochemical device according to any one of claims 1 to 4, wherein, The first metal porous body is a nickel-cobalt metal porous body.

6. The solid-state electrochemical device according to any one of claims 1 to 4, wherein, The first metal porous body is a nickel metal porous body.

7. The solid-state electrochemical device according to any one of claims 1 to 4, wherein, The first metal porous body is a nickel-tin metal porous body.

8. The solid-state electrochemical device according to any one of claims 1 to 7, wherein, The solid-state electrochemical device further has: A second electrode having an eighth major surface and a ninth major surface opposite to the eighth major surface, and arranged such that the eighth major surface faces the second major surface; A second current collector having a tenth major surface and an eleventh major surface opposite to the tenth major surface, and arranged such that the tenth major surface faces the ninth major surface; And A second connector having a twelfth major surface, and arranged such that the twelfth major surface faces the eleventh major surface, The twelfth major surface of the second connector is a flat surface, The second current collector is composed of a second metal porous body having a three-dimensional network structure, A plurality of second through-holes extending along a fourth direction from the tenth major surface to the eleventh major surface are formed on the tenth major surface.

9. The solid-state electrochemical device according to claim 8, wherein, When looking down at the tenth major surface, the second through-holes have a third width along a fifth direction orthogonal to the fourth direction, and a fourth width along a sixth direction orthogonal to the fourth direction and the fifth direction, The average value of the third width and the fourth width is 2 mm or more and 20 mm or less.

10. The solid-state electrochemical device according to claim 8 or 9, wherein, The percentage of the total area of the second through-holes relative to the area of the tenth major surface, that is, the third opening ratio, is 2.0% or more and 35% or less.

11. The solid-state electrochemical device according to any one of claims 8 to 10, wherein, In each of the nine second regions set by dividing the tenth main surface on an area basis, the percentage of the total area of the second through-holes in the second region with respect to the area of the second region, that is, the fourth opening ratio, is 2.0% or more and 35% or less.

12. The solid-state electrochemical device according to any one of claims 8 to 11, wherein, The second metal porous body is a nickel-cobalt metal porous body.

13. The solid-state electrochemical device according to any one of claims 8 to 11, wherein, The second metal porous body is a nickel metal porous body.

14. The solid-state electrochemical device according to any one of claims 8 to 11, wherein, The second metal porous body is a nickel-tin metal porous body.

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