JP2018036018A - Electric furnace for SOFC cell evaluation - Google Patents

Abstract

To visually grasp a stacking surface of a cell stack when the cell stack is evaluated and tested in an actual usage pattern. At least four or more through holes (3a) that are tapered holes that gradually increase in diameter from the outer surface to the inner surface of the heat insulating material (3) are provided at equal intervals along the circumferential direction of the heat insulating material (3). The housing 2 in which the heat insulating material 3 is accommodated has the same number of openings 2a as the holes 3a so as to face the through holes 3a. The operator can observe the stacked surface of the cell stack 10 from the plurality of openings 2a using an observation device. [Selection] Figure 1

Description

  The present invention relates to an electric furnace for SOFC cell evaluation that evaluates the performance of a cell stack of a solid oxide fuel cell (SOFC).

  In recent years, fuel cells, which are power generation devices that use a power generation method based on an electrochemical reaction, have attracted attention because they have high energy conversion efficiency and can be expected to significantly reduce carbon dioxide emissions. Fuel cells are divided into several types depending on the electrochemical reaction and the type of electrolyte. Among various types of fuel cells, solid oxide fuel cells (SOFCs) are particularly high in power generation capacity and burden on the environment. Therefore, it is expected as a next-generation energy supply source, and research and development for practical use is underway.

  The smallest unit cell (single cell) constituting the SOFC includes a solid electrolyte having a dense structure made of an oxygen ion conductor, an air electrode (cathode) having a porous structure formed on one surface of the solid electrolyte, It is comprised from the fuel electrode (anode) of the porous structure formed in the other surface of a solid electrolyte. Oxygen in the air supplied onto the air electrode is electrochemically reduced to oxygen ions, and when the oxygen ions reach the fuel electrode through the electrolyte membrane, the oxygen ions are supplied to the fuel electrode such as hydrogen. Is oxidized to emit electrons to an external load, and electric energy is generated.

  Further, when performing an evaluation test of a single cell of SOFC, the cell is accommodated in an electrochemical cell evaluation holder disclosed in Patent Document 1 below, and this evaluation holder is installed in an electric furnace at a constant high temperature (for example, 700 to 1000 ° C.) The evaluation test is performed while changing the measurement conditions (for example, the atmospheric temperature in the electric furnace and the current value to the cell part).

JP 2016-46040 A

  By the way, when generating power by SOFC, only a few tens of watts of output can be obtained with a single cell. Therefore, a cell, a current collector, a separator, etc. It is necessary to generate electric power using a cell stack in which a plurality of cell portions each having a set of layers are stacked to increase the output density.

  However, since only one set of cell parts can be accommodated in the holder for evaluation of Patent Document 1, the temperature distribution on the front and back surfaces of the cell part and mechanical damage (cracks) on the front and back surfaces in the electric furnace are observed in real time. Is possible, but does not support cell stacks. Therefore, it is desired to observe various phenomena that occur in a state in accordance with the actual operation as a performance evaluation test from the outside in real time, such as the state observation of the stacked surface (side surface) of the cell stack.

  Therefore, the present invention has been made in view of the above problems, and when a performance evaluation test of a cell stack in which a plurality of SOFC cells are stacked is performed, the state of the stack can be visually observed from the outside. An object of the present invention is to provide an electric furnace for SOFC cell evaluation.

In order to achieve the above-described object, a first aspect of the present invention is a SOFC cell in which a heater is wound around an inner peripheral surface and an electrolyte is sandwiched between a fuel electrode and an air electrode. A bottomed cylindrical heat insulating material that accommodates a cell stack formed by laminating a plurality of layers,
A housing in which the heat insulating material is accommodated;
An electric furnace for SOFC cell evaluation having
In the heat insulating material, tapered through-holes that gradually increase in diameter from the outer peripheral surface toward the inner peripheral surface are formed at equal intervals in at least four locations along the circumferential direction so as to surround the cell stack to be accommodated. And
The SOFC evaluation electric furnace is characterized in that an opening for observation by an observation device is formed in the casing so as to oppose the formation position of the through hole.

  According to the present invention, at least four through-holes are formed so as to surround the stack so that the stacked surface of the cell stack can be observed, and openings are formed facing the through-holes. Therefore, when a practical evaluation test of the cell stack is performed, it is possible to visually grasp the stacked surface of the cell stack using an observation device.

1 is a schematic perspective view of an electric furnace for SOFC evaluation according to the present invention. It is AA schematic sectional drawing of the same electric furnace. It is BB schematic sectional drawing of the same electric furnace.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the present invention is not limited by this embodiment, and all other forms, examples, operation techniques, etc. that can be implemented by those skilled in the art based on this form are included in the scope of the present invention. .

  As shown in any of FIGS. 1 to 3, an electric furnace for SOFC cell evaluation (hereinafter simply referred to as “electric furnace”) 1 according to the present invention is an inner periphery of a heat insulating material 3 accommodated in a housing 2. A heater 4 is wound around the surface, and a pedestal 5 on which a cell stack 10 serving as a test body is placed is disposed at a substantially central portion of the bottom 3 e of the heat insulating material 3.

A cell stack 10 serving as a test body is, for example, YSZ (yttria stabilized zirconia) or ScSZ (scandia stable) between a fuel electrode such as YSZ / Ni cermet and an air electrode such as (La, Sr) MnO _3. A single cell for SOFC constructed by integrating an electrolyte such as zirconia), a current collector for a fuel electrode composed of a Ni net that is stable in a reducing atmosphere, and a noble metal that is difficult to oxidize at high temperatures. A current collector for an air electrode composed of a net made of gold (Au) or platinum (Pt) and a pair of separators (interconnectors) for forming a flow path of air gas or fuel gas and separating each gas. A plurality of cell portions in a set are stacked.

  The housing | casing 2 is a container which shape | molded the steel material in the bottomed cylindrical shape so that the heat insulating material 3 might be covered. The casing 2 has a diameter that is several cm larger than the diameter of the heat insulating material 3 so that an air layer having a predetermined width is formed in a gap with the outer peripheral surface of the heat insulating material 3. Thereby, there is no direct contact with the heat insulating material 3 at the time of observation.

Further, the same number of openings 2a having a diameter larger than the outer diameter of the through hole 3a of the heat insulating material 3 are formed on the side surface of the housing 2 at positions facing the through hole 3a. In FIG. 2, since eight through-holes 3a are formed, the same number (eight) of the openings 2a is formed accordingly.

  The heat insulating material 3 is a container in which ceramic fibers are molded into a bottomed cylindrical shape. Further, in the wall of the heat insulating material 3, a heater storage portion 3 b (two steps up and down in FIG. 2) is formed that winds the heater 4 over the entire circumference. By making the heat insulating material 3 cylindrical, it is excellent in temperature accuracy and suitable for uniform heating, and precise temperature control and temperature gradient are possible.

  In addition, a circular lid portion 3 c formed of the same material is attached to the upper portion of the heat insulating material 3. The lid portion 3c is divided into a plurality of parts (in this embodiment, two parts), and is fitted to an opening part above the heat insulating material 3 (an outlet of the cell stack 10).

Further, a gas supply pipe for supplying fuel gas and air gas to the cell stack 10 installed on the pedestal 5 and a gas discharge pipe for discharging each gas are provided outside the furnace at a substantially central portion of the lid 3c. An insertion hole 3d is formed so as to be exposed.

  As shown in FIG. 2, the heat insulating material 3 has the through-hole 3a along the circumferential direction so that the laminated surface (side surface) of the cell stack 10 installed on the pedestal 5 provided on the bottom 3e is in a visible position. Are formed. In the present embodiment, eight through holes 3a are formed at equal intervals along the circumferential direction of the heat insulating material 3, and the heat insulating material 3 has a cylindrical shape. The observation distance to the cell stack 10 is substantially the same.

In this way, by forming the plurality of through holes 3a so as to surround the cell stack 10 to be accommodated, when the evaluation test is performed, the stacked state of the cell stack 10 can be observed over the entire circumferential direction. It becomes possible.

  In order not to disturb the heat insulating effect of the heat insulating material 3, the through hole 3a is a tapered hole that gradually increases in diameter from the outer surface to the inner surface as shown in FIG. What is necessary is just to shape | mold this taper angle suitably according to the angle of view of the observation equipment used at the time of observation.

  In the electric furnace 1 of the present invention, the opening 2a of the housing 2 and the through-hole 3a arranged to face each other through the air layer are provided continuously. That is, since there is no member such as a window between the opening 2a and the cell stack 10 installed on the pedestal 5, the operator can connect the opening 2a with an infrared camera, an X-ray camera, or the like. By aligning the imaging means (lens) of the observation device, the state of the cell stack 10 installed on the pedestal 5 can be directly observed.

  A temperature measuring hole 6 for inserting a thermometer (not shown) for measuring and controlling the temperature in the furnace is formed on the side surface of the housing 2. In FIG. 3, one electric furnace 1 is formed in each of the upper part and the lower part in the furnace. Further, a terminal cover 7 that covers a terminal group (not shown) such as a power input terminal of the heater 4 is provided on the side surface of the housing 2.

  The pedestal 5 is made of the same material (ceramic fiber) as the heat insulating material 3 and can be adjusted in height according to the height dimension of the cell stack 10 according to the thickness of the stacked surface of the cell stack 10. Thus, alignment can be performed so that the center portion of the laminated surface and the center of the through hole 3a face each other.

  When the cell stack 10 is observed with the electric furnace 1 described above, the lid 3c is first opened, the cell stack 10 is installed on the base 5, and the fuel gas and air gas introduction pipes are set in the cell stack 10, respectively. Then, the lid 3c is closed and the evaluation test is started.

  When the evaluation test is started, in order to observe the state change of the cell stack 10, the stacked surface of the cell stack 10 is observed from the plurality of openings 2a using an observation device. As an observation method using an observation device, for example, a method in which a plurality of observation devices are arranged at a necessary place and observation is performed simultaneously, or a rail for moving the device is laid around the casing 2 and a predetermined cycle of each through hole 3a. There are ways to observe in order.

  For example, when a high-temperature change part is discovered when observed with an infrared camera, the cause of the abnormality at the time of occurrence of an abnormality can be determined by immediately and visually grasping the state of the change part. It becomes easy to do.

  As described above, in the electric furnace 1 according to the present invention, the plurality of tapered through-holes 3 a surround the periphery of the cell stack 10 installed in the pedestal 5 at equal intervals along the circumferential direction of the heat insulating material 3. Therefore, when the evaluation test of the cell stack 10 is performed, the state of the stacked surface (side surface) of the stack 10 can be visually observed.

  In addition, since the through hole 3a and the opening 2a are not provided with a window (a quartz window or a sapphire window) and communicates from the opening 2a to the cell stack 10, the cell stack 10 as a specimen is photographed. In doing so, it is not necessary to consider the infrared transmission characteristics of the window material, and the state of the cell stack 10 can be observed only by photographing directly.

1 ... Electric furnace for SOFC evaluation 2 ... Housing (2a ... Open hole)
3 ... Insulating material (3a ... through-hole, 3b ... heater housing part, 3c ... lid part, 3d ... insertion hole, 3e ... bottom part)
4 ... heater 5 ... pedestal 6 ... temperature measuring hole 7 ... terminal cover 10 ... cell stack

Claims (1)

A bottomed cylindrical thermal insulation that houses a cell stack in which a plurality of SOFC cells are stacked, with a heater wound around the inner surface and an electrolyte sandwiched between the fuel electrode and the air electrode Material,
A housing in which the heat insulating material is accommodated;
An electric furnace for SOFC cell evaluation having
In the heat insulating material, at least four or more tapered through holes that gradually increase in diameter from the outer peripheral surface toward the inner peripheral surface are formed at equal intervals along the circumferential direction so as to surround the cell stack to be accommodated. And
An electric furnace for SOFC cell evaluation, wherein an opening for observation by an observation device is formed in the casing so as to face the formation position of the through hole.

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