JP2016081821A - Manufacturing method for fuel battery cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem in that, in a conventional fuel battery cell, strength is not imparted to an electrode layer after manufacturing, therefore, improvement has been demanded to increase the strength of the electrode layer.SOLUTION: To manufacture a fuel battery cell 1 having a structure sandwiching an electrolyte layer 2 between a pair of electrode layers 3, 4, and in which a metal support 5 is joined to the one electrode layer 3, the one electrode layer 3, electrolyte layer 2, and the other electrode layer 4 are formed on the surface of the metal support 5 while a formation area A for at least the electrode layer 2 of the metal support 5 is bent and deformed in a spherical shape. After the formation of the electrolyte layer 2 and electrode layers 3, 4, these are flattened. Thereby, residual compression stress can be applied to at least one electrode layer 3. Thus, tensile-resisting load performance for the electrode layer 3 can be improved. Accordingly, the fuel battery cell 1 having an electrode layer 3 excellent in strength can be obtained.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fuel cell constituting a power generation element of a fuel cell, and has a structure in which an electrolyte layer is sandwiched between a pair of electrode layers, and a metal support type fuel cell in which a metal support is joined to one electrode layer. It is related with the manufacturing method.

  As a method for manufacturing this type of fuel cell, for example, there is one described in Patent Document 1. The fuel cell manufacturing method described in Patent Document 1 has a structure in which an electrolyte is sandwiched between an anode (fuel electrode) and a cathode (air electrode), and a fuel cell in which a metal support is bonded to the cathode side. To do.

  In the manufacturing method, a cathode is formed on a metal support and accommodated in a heating means. At that time, the metal support having a high coefficient of thermal expansion is shielded by a shielding plate to make it difficult for heat to be transmitted, and the cathode is selectively transferred. Heat rapidly. As a result, the difference in thermal expansion between the metal support and the cathode during heating is made as small as possible to suppress warping due to the difference in thermal expansion.

JP 2013-041717 A

  By the way, since the electrolyte / electrode layer in the metal support type fuel cell as described above is formed of a ceramic brittle material, it has a property of being strong against compression but weak against tension. In contrast, the conventional fuel cell manufacturing method can reduce the warpage caused by the difference in thermal expansion coefficient at the time of manufacturing, but it can eliminate the warp completely, Since strength (compressive residual stress) is not imparted, improvement in improving the strength of the electrolyte / electrode layer has been demanded.

  The present invention has been made in view of the above-described conventional situation, and has a structure in which an electrolyte layer is sandwiched between a pair of electrode layers, and a metal support type fuel battery cell in which a metal support is joined to one electrode layer. It is an object of the present invention to provide a fuel cell having an electrolyte / electrode layer excellent in strength.

  A method for producing a fuel cell according to the present invention is a method for producing a metal support type fuel cell having a structure in which an electrolyte layer is sandwiched between a pair of electrode layers and a metal support is joined to one electrode layer. is there. And the manufacturing method of a fuel cell makes the state where the formation area of at least the electrode layer of the metal support is bent and deformed into a spherical shape, and forms one electrode layer, electrolyte layer and the other electrode layer on the surface of the metal support. It is characterized by forming.

  According to the method of manufacturing a fuel cell according to the present invention, after forming one electrode layer, an electrolyte layer, and the other electrode layer on a metal support, they are flattened, so that at least one electrode layer or electrolyte is formed. Residual compressive stress can be applied to the fuel cell, thereby improving the tensile load resistance of the electrolyte / electrode layer and providing a fuel cell having an electrolyte / electrode layer with excellent strength.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows 1st Embodiment of the manufacturing method of the fuel cell concerning this invention, Comprising: The top view (A) of a fuel battery cell, sectional drawing (B) of the principal part of a fuel battery cell, Bending a fuel battery cell It is sectional drawing (C) which shows the state changed, and sectional drawing (D) which shows the state which planarized the fuel cell. Cross-sectional explanatory view (A) showing internal stress state during application and firing of electrode layer, cross-sectional explanatory view (B) showing internal stress state during cooling after firing, and cross-sectional explanation showing internal stress state after flattening It is a figure (C). It is sectional drawing which shows 2nd Embodiment of the manufacturing method of the fuel cell concerning this invention. It is sectional drawing which shows 3rd Embodiment of the manufacturing method of the fuel cell concerning this invention. It is sectional drawing which shows 4th Embodiment of the manufacturing method of the fuel cell concerning this invention. It is sectional drawing (A) of the fuel battery cell which shows 5th Embodiment of the manufacturing method of the fuel battery cell concerning this invention, and sectional drawing (B) of the planarized fuel battery cell.

<First Embodiment>
A fuel cell 1 shown in FIGS. 1A and 1B constitutes a power generation element of a fuel cell, and has a structure in which an electrolyte layer 2 is sandwiched between a pair of electrode layers (3, 4). The metal support 5 is joined to one electrode layer (3).

  The fuel cell 1 of this embodiment has a configuration in which a circular metal support 5 that is slightly larger than these is disposed concentrically with respect to the circular electrolyte layer 2 and electrode layers (3, 4). The fuel cell 1 may naturally have a shape other than a circle. Further, in the fuel cell 1, the metal support 5 occupies most of the cross section in the thickness direction shown in FIG. 1B, and the electrolyte layer 2 and the electrode layers (3, 4) are in comparison with the metal support 5. It is very thin.

  The pair of electrode layers are an anode (fuel electrode layer) 3 and a cathode (air electrode layer) 4. In the illustrated example, the metal support 5 is bonded to the anode 3. The anode 3 has a larger thermal expansion coefficient with respect to temperature than the electrolyte layer 2 and the cathode 4, and has a larger thermal expansion coefficient than the metal support 5.

  The electrolyte layer 2 is, for example, 8 mol% yttria stabilized zirconia. The anode 3 is a ceramic porous material such as nickel + yttria stabilized zirconia. The cathode 4 is, for example, lanthanum strontium cobalt iron oxide. Moreover, the metal support body 5 is formed with the porous material made from stainless steel as an example, and the porosity is 20%-60%.

  In order to manufacture the fuel cell 1 described above, as shown in FIG. 1C, at least the electrode layer (3, 4) formation region A of the metal support 2 is bent and deformed into a spherical shape. Then, one electrode layer (3) is formed on the surface of the metal support 1, and then the electrolyte layer (2) and the other electrode layer (4) are formed.

  Here, in order to bend and deform the metal support 5, a jig 50 having a spherical surface is used. That is, the metal support 1 is bent and deformed into a spherical shape by pressing with the spherical surface of the jig 50 with the peripheral edge held.

  At this time, the spherical surface of the jig 50 has a curvature corresponding to the deformation amount of the fuel cell obtained experimentally in advance. This is because, when each electrode layer and electrolyte layer are formed on a flat metal support and the bending deformation after the formation is analyzed three-dimensionally, a two-dimensional circle defined by the height of warpage at the radius of the fuel cell is obtained. It turns out that it almost overlaps. Therefore, the spherical surface of the jig 50 corresponds to the curvature of the two-dimensional circle. That is, the spherical surface of the jig 50 has a curvature that can impart to the metal support 5 a warp amount (bending deformation amount) caused by a difference in thermal expansion. In FIG. 1C, the amount of bending deformation is exaggerated, and the actual amount of bending deformation is smaller than shown.

  In this embodiment, the bending deformation of the metal support 5 is elastic deformation. Therefore, the metal support 5 returns to a flat initial state when the pressure applied by the jig 50 is released. Furthermore, in this embodiment, when the metal support 5 is bent and deformed, at least the formation region A of the electrode layers (3, 4) is generally constant as shown in FIG. Bend and deform with the curvature of. Therefore, the spherical surface of the jig 50 also has a constant curvature as a whole.

  Furthermore, in this embodiment, since the thermal expansion coefficient of the anode 3 that is one of the electrode layers is larger than the thermal expansion coefficient of the metal support body 5 as described above, the convex surface of the metal support body 5 deformed by bending is formed. The anode 3 is formed, and then the electrolyte layer 2 and the cathode 4 are formed.

  The anode 3 can be formed, for example, by applying an anode material to the metal support 5 by screen printing and firing at a temperature (for example, 1000 degrees or less) at which the Young's modulus of the metal support 5 does not significantly decrease. The anode 3 can also be formed by sputtering, and the electrolyte layer 2 and the cathode 4 can be formed by the same method as the anode 3.

  Here, FIGS. 2A to 2C are views showing an internal stress state in the manufacturing process of the fuel cell 1. As shown in FIG. 2 (A), tensile stress is generated on the outer side (upper surface side) and compressive stress is generated on the inner side (lower surface side) in the stage where bending deformation is applied to the metal support 5. When the anode 3 as an electrode layer is applied to the metal support 5 and fired, no stress is generated in the anode 3 (stress free) as shown in FIG.

  Next, after firing of the anode 3 and during cooling, as shown in FIG. 2B, the metal support 5 is subjected to a large compressive stress on the inside as the shrinkage occurs, and the anode 3 is tensioned. Stress is generated. When the fuel cell 1 is flattened as shown in FIG. 1D, residual compressive stress is applied to the metal support 5 as shown in FIG. A small residual compressive stress is applied.

  That is, in the above fuel cell manufacturing method, the thermal expansion between the two layers generated during cooling after firing is performed by applying mechanical tensile strain to the metal support 5 during the application and firing of the anode 3. Due to the strain due to the difference, the tensile stress is reduced on the metal support 5 side, and the tensile stress is applied on the anode 3 side. Thereafter, when the bending deformation is removed, the metal support 5 side is compressed, and the tensile stress on the anode 3 side is reduced to follow the compression.

  As described above, in the fuel cell manufacturing method described above, since the ceramic brittle material used for the anode 3 is strong in compression but weak in tension, the residual compressive stress is applied to the anode 3 in advance. This has the effect of reducing the tensile input during actual use. Thereby, the tensile load resistance performance and strength reliability of the anode 3 are improved, and the fuel cell 1 having the anode 3 having excellent strength can be provided. Moreover, since the curvature radius of the spherical surface of the jig 50 can be arbitrarily set, the strength of the residual compressive stress can be adjusted according to the material used.

  Further, in the above fuel cell manufacturing method, at least the electrode layer forming region of the metal support 5 is bent into a spherical shape to form one electrode layer (anode 3). As a result, measures for improving the strength are taken only in the portion where the stress is generated, and simplification of the jig 50 and unnecessary application of stress to the fuel cell 1 can be avoided.

  Further, in the fuel cell manufacturing method described above, the bending deformation of the metal support 5 is elastic deformation. Therefore, when the mechanical load on the metal support 5 is released, the fuel cell 1 is naturally flat. Thus, the fuel battery cell 1 having the anode 3 having excellent strength can be easily obtained without performing special processing.

  Furthermore, in the fuel cell manufacturing method described above, the thermal expansion coefficient of one electrode layer (anode 3) is larger than the thermal expansion coefficient of the metal support 5, and one of the convex surfaces of the metal support 5 that is bent and deformed. Since the electrode layer (anode 3) is formed, a residual compressive stress can be applied to the anode 3 to improve the tensile load resistance performance and strength reliability of the anode 3, and the fuel cell having the anode 3 having excellent strength 1 can be provided.

  Furthermore, in the above fuel cell manufacturing method, when the metal support 5 is bent and deformed, it is bent and deformed with a constant curvature as a whole, so that the stress and strain inside the metal support 5 are the same over the entire surface. Thus, the stress due to the difference in thermal expansion with the anode 3 can be uniformly reduced over the entire surface.

  3-6 is a figure explaining the 2nd-5th embodiment of the manufacturing method of the fuel cell concerning this invention. In the following embodiments, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

Second Embodiment
The fuel cell manufacturing method shown in FIG. 3 is a case where the thermal expansion coefficient of the anode 3 which is one of the electrode layers is smaller than the thermal expansion coefficient of the metal support body 5, and is bent and deformed. The anode 3 is formed on the concave surface. In this case, means for bending and deforming the metal support 5 is not particularly limited. For example, a jig 50 having a suction port on the concave surface is used, and the metal support 5 is attracted to the concave surface by negative pressure to bend and deform. Is possible.

  In this embodiment, the metal support 5 and the anode 3 are subjected to the same internal stress in the metal support 5 as that of the anode 3 shown in FIG. 2, and the anode 3 has the metal support 5 shown in FIG. Equivalent internal stress will occur. As a result, when flattening, the residual compressive stress is applied to the anode 3 in the same manner as the residual compressive stress is applied to the metal support 5 shown in FIG.

  As described above, in the fuel cell manufacturing method described above, when the thermal expansion coefficient of the anode 3 is smaller than the thermal expansion coefficient of the metal support 5 and when the excessive residual compressive stress is relieved, bending is performed. The anode 3 is formed on the concave surface of the deformed metal support 5. Thereby, residual compressive stress can be given to the anode 3, the tensile load resistance performance and strength reliability of the anode 3 can be improved, and the fuel cell 1 having the anode 3 having excellent strength can be provided.

<Third Embodiment>
In the method of manufacturing the fuel cell shown in FIG. 4, when the metal support 5 is bent and deformed, the bending of the metal support 5 is performed by relatively reducing the curvature of the low temperature region B that is relatively low in power generation. .

  In the circular fuel cell 1 as shown in FIG. 1 (A), the temperature in the vicinity of the center having a large heat capacity is relatively low, so that the center of the other outer portion with respect to the curvature (curvature radius r) is relatively small. The curvature of the low temperature region B in the vicinity is reduced. Therefore, at the boundary portion C between the outer portion and the low temperature region B, the curvature is large, that is, the curvature radius (r / a) is small.

  The fuel cell manufacturing method described above can achieve the same operations and effects as the previous embodiment. Further, in the fuel cell manufacturing method described above, when a temperature difference occurs in the plane of the fuel cell 1, tensile stress is generated on the low temperature side due to the difference in thermal expansion inside the material. By reducing the curvature of the low-temperature region B, it is possible to partially apply a large residual compressive stress in advance, and to more reliably prevent the anode 3 from being broken by a tensile stress.

<Fourth embodiment>
In the fuel cell manufacturing method shown in FIG. 5, the metal support 5 has a high-rigidity portion D having a relatively high bending rigidity corresponding to the low-temperature region B where the temperature is relatively low during power generation. Yes.

  The fuel cell manufacturing method described above can achieve the same operations and effects as the previous embodiment. Further, in the fuel cell manufacturing method described above, in the low temperature region B where the temperature is low and the tensile stress is high in the plane of the fuel cell 1, the rigidity of the metal support 5 is increased, thereby partially Accordingly, it is possible to increase the bending stress and to increase the residual compressive stress at the time of unloading the bending load.

<Fifth Embodiment>
In the method of manufacturing the fuel cell shown in FIG. 6, after the bending deformation of the metal support 5 is plastic deformation, one electrode layer (anode 3), the electrolyte layer 4 and the other electrode layer (cathode 4) are formed. The metal support 5 is flattened.

  That is, in the above fuel cell manufacturing method, the fuel cell 1 after forming the electrolyte layer 4 and the other electrode layer (cathode 4) is deformed into a curved surface as shown in FIG. It remains. Therefore, the fuel cell 1 is flattened using another means. As described above, the amount of bending deformation is exaggerated in the drawings, and the actual amount of bending deformation is smaller than that shown in the drawing.

  In order to make the fuel cell 1 flat, there is a method in which pressure molding is performed using press jigs 51 and 52 that are divided vertically as shown in FIG. 6B. Further, when a fuel cell is manufactured using the fuel cell 1 that is still curved and a fuel cell stack is formed by stacking a plurality of fuel cells, the fuel cell stack can be flattened by an assembly surface pressure of stacking.

 In the fuel cell manufacturing method described above, a compressive stress is imparted to the metal support 5 and a tensile stress is imparted to the anode 3 due to the difference in thermal expansion during the film formation of the anode 3 even in a bent state in advance. It will be in the state. Therefore, since the residual tensile stress is applied to the metal support 5 and the residual compressive stress is applied to the anode 3 at the stage where the fuel cell 1 is flattened, as a result, as in the previous embodiment, The tensile load resistance performance and strength reliability of the anode 3 can be improved.

  Further, when the method of flattening the fuel cell 1 with the stacking surface pressure of the stacking is adopted, the step of flattening the fuel cell 1 becomes unnecessary, which contributes to reduction of manufacturing man-hours and manufacturing cost. can do.

  The method of manufacturing a fuel cell according to the present invention is not limited to the above embodiments, and the details of the configuration can be changed as appropriate without departing from the gist of the present invention. Further, in each of the above embodiments, the case where the metal support 5 is bonded to the anode having a large change in the coefficient of thermal expansion with respect to the temperature compared to the electrolyte layer and the cathode is illustrated, but the case where the metal support is bonded to the cathode side. There is also a possibility.

DESCRIPTION OF SYMBOLS 1 Fuel cell 2 Electrolyte layer 3 Anode (one electrode layer)
4 Cathode (the other electrode layer)
5 Metal support A Electrode layer formation area B Low temperature area D High rigidity part

Claims (8)

In producing a fuel cell having a structure in which an electrolyte layer is sandwiched between a pair of electrode layers and having a metal support bonded to one electrode layer,
Forming at least the electrode layer forming region of the metal support in a spherically deformed state, forming one electrode layer on the surface of the metal support, and thereafter forming the electrolyte layer and the other electrode layer A manufacturing method of a fuel cell characterized by the above.   2. The method of manufacturing a fuel cell according to claim 1, wherein the bending deformation of the metal support is elastic deformation.   2. The fuel cell according to claim 1, wherein the bending deformation of the metal support is plastic deformation, and the fuel cell is flattened after forming one electrode layer, the electrolyte layer, and the other electrode layer. Manufacturing method.   The thermal expansion coefficient of one electrode layer is larger than the thermal expansion coefficient of the metal support, and one electrode layer is formed on the convex surface of the bent metal support. 2. A method for producing a fuel battery cell according to item 1.   The thermal expansion coefficient of one electrode layer is smaller than the thermal expansion coefficient of the metal support, and one electrode layer is formed on the concave surface of the bent metal support. 2. A method for producing a fuel battery cell according to item 1.   The method of manufacturing a fuel cell according to any one of claims 1 to 5, wherein when the metal support is bent and deformed, the metal support is bent and deformed with a constant curvature as a whole.   The bending deformation of the metal support body according to any one of claims 1 to 5, wherein the bending of the metal support is performed by relatively reducing the curvature of a region that is relatively low in temperature during power generation. Manufacturing method of fuel cell.   6. The metal support according to claim 1, wherein the metal support has a high-rigidity portion having a relatively high bending rigidity corresponding to a region where the temperature is relatively low during power generation. The manufacturing method of the fuel cell described in 1.

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