JP2013055008A - Fuel cell device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell device which prevents a protection tube in which a temperature sensor is disposed and air in the protection tube from being cooled by air at the exterior of a container and allows the temperature in the container where multiple fuel cells are housed to be accurately measured.SOLUTION: In a fuel cell device, a protection tube 820, protruding to the inner side of a container 80, is fixed to a wall surface of the container 80, and a heat insulation material 8 is disposed so as to contact with the outer side of the wall surface to which the protection tube 820 is fixed. An opening area of a second insertion hole 852 formed in the heat insulation material 8 is smaller than an opening area of a first insulation hole 851 formed on the wall surface.

Description

  The present invention relates to a fuel cell device that generates power using a fuel gas and an oxidant gas.

  2. Description of the Related Art As a fuel cell device that generates power using a fuel gas and an oxidant gas, a fuel cell device having a structure in which a fuel cell assembly formed by electrically connecting a plurality of fuel cells is housed in a container is known. In the fuel cell device having such a structure, a temperature sensor is disposed inside the container in order to measure the temperature inside the container during operation of the fuel cell device. However, as described below, since the inside of the container of the fuel cell device is a harsh environment for the temperature sensor, it is not desirable to arrange the temperature sensor directly inside the container.

  During operation of the fuel cell device, it is necessary to maintain a temperature at which the fuel cell can generate electric power, so that the interior of the container is maintained at a high temperature. For example, in the case of a solid oxide fuel cell, the internal temperature of the container during operation reaches about 700 ° C. In addition to the high temperature inside the container, the container is filled with highly reactive gases such as residual fuel gas and oxidant gas that did not contribute to the power generation reaction, and water vapor generated by the power generation reaction. ing. For this reason, when the temperature sensor is directly arranged inside the container, the temperature sensor is damaged in a short period of time as a result of being exposed to such a harsh environment.

  Generally, when placing a temperature sensor inside a container in a harsh environment, a protective tube with one end opened and the other end sealed is placed on the inner wall of the container, and the temperature sensor is placed inside the protective tube. (See Patent Document 1 below). By adopting such a configuration, the temperature sensor is covered with the protective tube and is protected from a harsh environment, so that the temperature can be measured over a long period of time.

  However, when the temperature sensor is arranged inside the protective tube, the space inside the container where the temperature is actually measured and the space where the temperature sensor is arranged are separated by the protective tube. Yes. For this reason, if the air outside the container flows into the protective tube through the opening of the protective tube, the temperature around the temperature sensor decreases, and the temperature inside the container cannot be measured accurately. In order to prevent this, the following Patent Document 1 discloses a structure that seals the protective tube by attaching a lid to the opening of the protective tube and prevents air outside the container from flowing into the protective tube. Has been.

JP-A-8-210923

  When the protective tube is sealed by attaching a lid to the opening of the protective tube, the air outside the container can be prevented from flowing into the protective tube. However, since the lid is cooled by touching the air outside the container, the protective tube is cooled by heat conduction through the lid, and the temperature inside the container cannot be measured accurately.

  As a measure to solve this problem, the lid is not directly attached to the opening of the protective tube, but the lid is attached via a heat insulating material in which an insertion hole for inserting the temperature sensor is formed. Therefore, it is conceivable to seal the protective tube. With such a configuration, the protection tube can be prevented from being cooled by heat conduction through the lid. However, it is impossible to prevent the air inside the protective tube from being directly cooled by heat conduction through the lid, and due to this influence, the temperature inside the container cannot be measured accurately.

  In particular, in a fuel cell device in which the temperature inside the container is as high as about 700 degrees, when the temperature sensor comes into contact with the inner surface of the protective tube, both of them are seized, making it impossible to take out the temperature sensor from the protective tube. Problems arise. In order to prevent this, it is necessary to increase the distance between the inner surface of the protective tube and the temperature sensor. As a result of the increase in the volume of the protective tube and the lid, the air inside the protective tube is caused by heat conduction through the lid. The effect of cooling was not negligible.

  This invention is made | formed in view of such a subject, The objective is that the temperature sensor is arrange | positioned inside and the air inside a protection tube will be cooled by the air outside a container. An object of the present invention is to provide a fuel cell device capable of preventing and accurately measuring the temperature inside the container in which the fuel cell assembly is accommodated.

  In order to solve the above-described problems, a fuel cell device according to the present invention includes an internal channel in a fuel cell device that generates power using a fuel gas and an oxidant gas, and the fuel gas and A plurality of fuel cells to which one of the oxidant gases is supplied, a container that houses the plurality of fuel cells, and a heat insulating material disposed so as to come into contact with the wall surface of the container from the outside And through the first insertion hole formed in the wall surface and the second insertion hole formed in the heat insulating material, the thermocouple provided at the tip is located inside the container so as to be located inside the container. A rod-shaped temperature sensor disposed so as to protrude, and a protective tube fixed to the wall surface so as to cover the temperature sensor and the first insertion hole inside the container, and The opening area of the insertion hole is And wherein the smaller than the opening area of one insertion hole.

  According to the present invention, the protective tube is fixed to the wall surface of the container, and further, the heat insulating material is disposed on the outside of the wall surface. Therefore, it is possible to prevent the protection tube and the air inside the protection tube from being cooled by heat conduction from the air outside the container. Furthermore, since the opening area of the second insertion hole formed in the heat insulating material is smaller than the opening area of the first insertion hole formed in the wall surface of the container, the air inside the protective tube and the air outside the container are It will be separated by a heat insulating material. Therefore, it is possible to prevent the air inside the protective tube from being directly cooled by heat conduction through the lid. As described above, since the air outside the container is prevented from affecting the temperature measurement, the temperature inside the container can be accurately measured.

  In particular, even when the volume of the protective tube is increased, the temperature of the protective tube does not decrease, and the temperature of the air inside the protective tube does not decrease. Therefore, the internal temperature of the container can be accurately measured while reliably preventing seizure between the protective tube and the temperature sensor by forming the protective tube with a large volume.

  In the fuel cell device according to the present invention, it is preferable that a cover member that covers the heat insulating material is provided outside the heat insulating material, and the temperature sensor is fixed to the cover member.

  During operation of the fuel cell device, the wall surface of the container is very hot. For this reason, when the temperature sensor is fixed to the wall surface of the container, the temperature sensor is heated by heat conduction from the wall surface, and it becomes difficult to accurately measure the temperature inside the container. Therefore, in this preferred embodiment, the temperature sensor is fixed to the cover member instead of the wall surface of the container. Since the cover member is provided via a heat insulating material on the wall surface of the container that becomes high temperature, the temperature sensor is not heated by heat conduction. Therefore, the temperature inside the container can be measured more accurately.

  In the fuel cell device according to the present invention, a third insertion hole is formed in the cover member at a position corresponding to the second insertion hole, and the third insertion hole is formed outside the container. It is also preferable that a bush for holding the temperature sensor is inserted in a state in which the path through which the gas flows into the protective tube is blocked.

  In this preferred embodiment, when the temperature sensor is fixed to the cover member, a bush, which is a member different from the cover member, is inserted into a third insertion hole formed in the cover member. Holding the sensor. By configuring in this way, for example, the cover member can be formed of a highly rigid material in consideration of the function of firmly covering the heat insulating material. On the other hand, the bush can be formed of a highly elastic material in consideration of the function of holding the temperature sensor in a sealed state in order to reliably prevent air outside the container from flowing into the protective tube. That is, it is possible to form the respective materials with optimized materials.

  In the fuel cell device according to the present invention, the cover member is formed with a screw portion at a position corresponding to the third insertion hole, and the cap member is screwed into the screw portion and fastened. Further, it is preferable that the bush is fitted between the third insertion hole and the temperature sensor by being pressed by the cap member when the cap member is fastened.

  In this preferable aspect, the temperature sensor can be fixed in a sealed state with respect to the cover member with a simple configuration, and air outside the container can be prevented from flowing into the protective tube.

  In the fuel cell device according to the present invention, it is also preferable that the first insertion hole is formed so as to have substantially the same shape as an inner edge in a cross section perpendicular to the axial direction of the protective tube.

  In this preferred embodiment, the first insertion hole formed in the wall surface is formed to have substantially the same shape as the shape of the inner edge of the protective tube fixed to the portion. With such a configuration, the operation of welding the protective tube to the wall surface is facilitated, so that a leak hole is prevented from being formed between the protective tube and the wall surface due to a welding mistake. Accordingly, since no gas flows from the outside of the protective tube through the leak hole, the temperature inside the container can be accurately measured.

  According to the present invention, the protection tube in which the temperature sensor is disposed, and the air inside the protection tube are prevented from being cooled by the air outside the container, and the inside of the container in which the fuel cell assembly is accommodated. A fuel cell device capable of accurately measuring the temperature of the fuel cell can be provided.

It is a perspective view of the fuel cell module which removes and shows a cover member. FIG. 2 is a perspective view of the fuel cell device showing a state where a flow path member that covers the fuel cell assembly is removed from the fuel cell device shown in FIG. 1. It is sectional drawing of the fuel cell module shown in FIG. It is sectional drawing of the fuel cell module shown in FIG. It is a figure for demonstrating a fuel cell unit. It is a figure for demonstrating a fuel cell stack. It is a figure for demonstrating the specific structure and arrangement | positioning of a temperature sensor and a protective tube.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In order to facilitate the understanding of the description, the same constituent elements in the drawings will be denoted by the same reference numerals as much as possible, and redundant description will be omitted.

  FIG. 1 is a perspective view showing a fuel cell device FC which is an embodiment of the fuel cell device according to the present invention, and shows a state where a cover member 1 and a heat insulating material 8 are removed. FIG. 2 is a perspective view of the fuel cell device FC showing a state in which the flow path member 7 covering the fuel cell assembly 500 is removed from the fuel cell device FC shown in FIG. 3 is a cross-sectional view of the fuel cell device FC, and is a cross-sectional view in the vicinity of the center of the fuel cell device FC in the direction of arrow A in FIG. 4 is a cross-sectional view of the fuel cell device FC, and is a cross-sectional view in the vicinity of the center of the fuel cell device FC in the direction of arrow B in FIG. In FIGS. 3 and 4, cross-sectional hatching is omitted.

  The fuel cell assembly 500 is arranged in a state of being accommodated in a container 80 formed by the flow path member 7 and the partition plate 15. In the space formed between the container 80 and the cover member 1, the heat insulating material 8 is disposed so as to cover the entire container 80 except for a portion where an exhaust gas passage described later is formed. That is, the heat insulating material 8 is disposed so as to come into contact with the flow path member 7 constituting the wall surface of the container 80 from the outside. By disposing the heat insulating material 8 in this way, heat dissipation from the container 80 to the outside is suppressed. Further, the cover member 1 is disposed so as to abut on the outside of the heat insulating material 8, and the heat insulating material 8 is fixed.

  As shown in FIG. 3, a temperature sensor 800 is provided to measure the temperature inside the container 80 during operation of the fuel cell device FC. The temperature sensor 800 has a rod-like shape, and has a thermocouple 801 as a temperature measuring unit at one end and a lead wire 802 at the other end. The temperature sensor 800 is disposed through the flow path member 7, the heat insulating material 8, and the cover member 1 so that the thermocouple 801 is located inside the container 80 and the lead wire 802 is located outside the cover member 1. ing. Inside the container 80, a protective tube 820 is disposed so as to cover the thermocouple 801. Specific structures and arrangements of the temperature sensor 800 and the protective tube 820 will be described in detail later.

  The cover member 1 is formed in a rectangular parallelepiped shape by a side wall on the front side, a pair of side walls in the longitudinal direction, a side wall on the back side, and a ceiling. A flange portion is formed at the lower end portion of each side wall, and a space sealed by the cover member 1 and the base member 2 is formed by bringing the flange portion into contact with the base member 2. The cover member 1 and the base member 2 are fixed by bolts (not shown), and the bolts pass through the mounting holes provided in the cover member 1 and are fixed by passing through the mounting holes 2a provided in the base member 2. Has been.

  An internal space formed by the cover member 1 and the base member 2 is separated into two spaces by a partition plate 15. Among the spaces separated by the partition plate 15, the space where the fuel cell stack 400 is disposed is the power generation chamber 16. Of the spaces separated by the partition plate 15, the other space is an exhaust gas chamber 17. The inner wall surface of the cover member 1 and the partition plate 15 are in close contact with each other directly or indirectly through some kind of contact member (for example, a flexible thin plate member).

  The partition plate 15 is placed on a support member 15 a provided on the base member 2 and is held at a predetermined distance from the base member 2. A pair of support members 15a are provided so as to support the partition plate 15 at both ends in the longitudinal direction. Accordingly, a gap 15b is formed between the pair of support members 15a and 15a. Exhaust gas that has passed through an exhaust gas passage (not shown) provided on the wall surface of the cover member 1 is introduced into the exhaust gas chamber 17 through the gap 15b.

  The gas tank 3 is placed on the partition plate 15. Ten fuel cell stacks 400 are arranged side by side on the gas tank 3 to constitute a fuel cell assembly 500. Fuel gas is supplied from the gas tank 3 to the fuel cells 4 constituting each fuel cell stack 400.

  More specifically, an opening (not shown) having substantially the same shape as the lower support plate 400b of the fuel cell stack 400 is provided on the upper surface of the gas tank 3, and the lower support plate 400b is in close contact with the opening. Thus, the gas tank 3 and each fuel cell stack 400 are connected. Therefore, the fuel cells 4 constituting the fuel cell stack 400 are erected on the gas tank 3 with their tip portions facing upward.

  Each fuel battery cell 4 has a tubular shape, and a gas flowing from one end of the fuel battery cell 4 to the other end inside the pipe of the fuel battery cell 4 and outside the pipe from the one end to the other end. It operates by the action of the gas flowing to the part. In the present embodiment, the gas flowing in the pipe of the fuel battery cell 4 is a fuel gas such as reformed gas obtained by reforming hydrogen or hydrocarbon fuel, and the gas flowing outside the pipe of the fuel battery cell 4 contains oxygen. Contains oxidant gas such as air.

  Here, the fuel cell unit 30 including the fuel cells 4 will be described with reference to FIG. As shown in FIG. 5, the fuel cell unit 30 is a tubular structure formed by the fuel cells 4 and extending in the vertical direction, and includes a cylindrical fuel cell 4 and one end of the fuel cell 4. It has an inner electrode terminal 40 attached to 4a and an outer electrode terminal 42 attached to the other end 4b.

  The fuel cell 4 includes a cylindrical inner electrode layer 44, a cylindrical outer electrode layer 48, a cylindrical electrolyte layer 46 disposed between the electrode layers 44, 48, and an inner electrode. The fuel gas flow path 50 is formed inside the layer 44. Further, an inner electrode exposed peripheral surface 44a in which the inner electrode layer 44 is exposed to the electrolyte layer 46 and the outer electrode layer 48 at one end 4a of the fuel cell 4, and the electrolyte layer 46 is an outer electrode layer. An electrolyte exposed peripheral surface 46 a exposed to 48 is provided. The other end 4b of the fuel cell 4 is configured by an outer electrode exposed peripheral surface 48a from which the outer electrode layer 48 is exposed. The fuel gas channel 50 functions as a part of the in-pipe channel 30c. The inner electrode exposed peripheral surface 44 a is also an inner electrode outer peripheral surface that is in electrical communication with the inner electrode layer 44. The outer electrode exposed peripheral surface 48 a is also an outer electrode outer peripheral surface that is in electrical communication with the outer electrode layer 48.

  The inner electrode layer 44 includes, for example, a mixture of Ni and zirconia doped with at least one selected from rare earth elements such as Ca, Y, and Sc, ceria doped with at least one selected from Ni and rare earth elements, A mixture of Ni and a mixture of lanthanum gallate doped with at least one selected from Sr, Mg, Co, Fe, and Cu. The electrolyte layer 46 includes, for example, zirconia doped with at least one selected from rare earth elements such as Y and Sc, ceria doped with at least one selected from rare earth elements, lanthanum gallate doped with at least one selected from Sr and Mg, Formed from at least one of the following. The outer electrode layer 48 is made of, for example, lanthanum manganite doped with at least one selected from Sr and Ca, lanthanum ferrite doped with at least one selected from Sr, Co, Ni, and Cu, Sr, Fe, Ni, and Cu. It is formed from at least one selected from samarium cobalt and silver doped with at least one selected. In this case, the inner electrode layer 44 becomes a fuel electrode, and the outer electrode layer 48 becomes an air electrode. The thickness of the inner electrode layer 44 is, for example, 1 mm, the thickness of the electrolyte layer 46 is, for example, 30 μm, the thickness of the outer electrode layer 48 is, for example, 30 μm, and the outer diameter is For example, it is 1-10 mm.

  The inner electrode terminal 40 is arranged so as to cover the inner electrode exposed peripheral surface 44a from the outside over the entire circumference and is electrically connected to the inner electrode terminal 40a, and a tubular shape extending from the main body portion 40a in the longitudinal direction of the fuel cell 4. Part 40b. The main body portion 40a and the tubular portion 40b are cylindrical and concentrically arranged, and the tube diameter of the tubular portion 40b is smaller than the tube diameter of the main body portion 40a. The tubular portion 40b has a connection channel 40c that communicates with the fuel gas channel 50 and communicates with the outside. A step portion 40 d between the main body portion 40 a and the tubular portion 40 b is in contact with the end surface 44 b of the inner electrode layer 44.

  The outer electrode terminal 42 is disposed so as to cover the outer electrode exposed peripheral surface 48a from the outside over the entire circumference and is electrically connected thereto, and a tubular shape extending from the main body portion 42a in the longitudinal direction of the fuel cell 4. Part 42b. The main body portion 42a and the tubular portion 42b are cylindrical and concentric, and the tube diameter of the tubular portion 42b is smaller than the tube diameter of the main body portion 42a. The tubular portion 42b has a connection channel 42c that communicates with the fuel gas channel 50 and communicates with the outside. A step portion 42 d between the main body portion 42 a and the tubular portion 42 b is in contact with the outer electrode layer 48, the electrolyte layer 46, and the end surface 44 c of the inner electrode layer 44 via the annular insulating member 52.

  The overall shape of the inner electrode terminal 40 and the overall shape of the outer electrode terminal 42 are the same. Further, the inner electrode terminal 40 and the fuel battery cell 4, and the outer electrode terminal 42 and the fuel battery cell 4 are sealed and fixed by a conductive sealing material 54 over the entire circumference. The sealing material 54 is various brazing materials including, for example, silver, a mixture of silver and glass, gold, nickel, copper, and titanium.

  The connection channel 40 c of the inner electrode terminal 40, the fuel gas channel 50 of the fuel cell 4, and the connection channel 42 c of the outer electrode terminal 42 constitute an in-pipe channel 30 c of the fuel cell unit 30.

  Next, the fuel cell stack 400 including the fuel cell unit 30 will be described with reference to FIG. The fuel cell stack 400 includes 16 fuel cell units 30, an upper support plate 400a, a lower support plate 400b, a connection member 400c, and an external terminal 400d.

  The upper support plate 400a and the lower support plate 400b are rectangular, and are through holes (fitting holes) that fit into the tubular portions 40b and 42b of the fuel cell unit 30 so as to support the fuel cell unit 30 in 2 columns × 8 rows, respectively. (Not shown in the figure). The upper support plate 400a and the lower support plate 400b are formed of an electrically insulating material, for example, formed of heat resistant ceramics. Specifically, it is preferable to use alumina, zirconia, spinel, forsterite, magnesia, titania or the like.

  The 16 fuel cell units 30 are arranged so that they are electrically connected in series. Specifically, the fuel cell units 30 are arranged so that the inner electrode terminals 40 of the adjacent fuel cell units 30 are alternately arranged on the upper side and the lower side. Further, a connection member 400c for electrically connecting the 16 fuel cell units 30 in series is provided. The connection member 400c electrically connects one adjacent inner electrode terminal 40 and one outer electrode terminal 42. Each of the inner electrode terminal 40 and the outer electrode terminal 42 at both ends of the 16 fuel cell units 30 connected in series is provided with an external terminal 400d for electrical connection with the outside. The connection member 400c and the external terminal 400d are made of, for example, a heat-resistant metal such as stainless steel, a nickel base alloy, or a chromium base alloy, or a ceramic material such as lanthanum chromite. The external terminals 400d of each fuel cell stack 400 are electrically connected in series, and are connected to the electrode rods 13 and 14 at both ends thereof.

  As described with reference to FIGS. 5 and 6, in the fuel cell stack 400, the end 4a of the fuel cell unit 30 where the inner electrode terminal 40 is provided and the end where the outer electrode terminal 42 is provided. The parts 4b are arranged so as to alternate with each other.

  Here, returning to FIGS. 1 to 4, the description of the fuel cell device FC will be continued. In the present embodiment, the reformer 5 is disposed so as to be located above the fuel cell stack 400. A pipe 6C and a pipe 6D are connected to the reformer 5, and the reformer 5 is positioned above the fuel cell stack 400 at a predetermined interval by the pipe 6C and the pipe 6D. Is retained. The pipe 6 </ b> C is a pipe for supplying city gas, air, and water vapor as reformed gas to the reformer 5, and is erected with respect to the partition plate 15. The pipe 6 </ b> D is a pipe for supplying the fuel gas reformed in the reformer 5 to the gas tank 3, and is erected with respect to the gas tank 3.

  The city gas and air supplied to the reformer 5 through the pipe 6C are introduced into the fuel cell apparatus FC through the reformed gas supply pipe 6A. Further, the steam supplied to the reformer 5 through the pipe 6C is introduced into the fuel cell device FC through the steam supply pipe 6B. The to-be-reformed gas supply pipe 6A and the water vapor supply pipe 6B are connected to a mixing chamber 15c provided on the opposite side of the pipe 6C with the partition plate 15 in between. The city gas and air supplied from the reformed gas supply pipe 6A and the water vapor supplied from the steam supply pipe 6B are mixed in the mixing chamber 15c and supplied to the pipe 6C.

  Although not explicitly shown in FIGS. 1 to 4, in this embodiment, electromagnetic valves are attached to the reformed gas supply pipe 6 </ b> A and the steam supply pipe 6 </ b> B, respectively, and each electromagnetic valve is output from a CPU as a control unit. The ratio of the gas to be reformed, air, and water vapor supplied to the reformer 5 can be changed by opening and closing according to the instruction signal.

  City gas (which may be mixed with steam) and air (which may be only reformed gas) as reformed gas introduced into the reformer 5 are contained in the reformer 5. The reforming catalyst is reformed. The reformed fuel gas is supplied to the gas tank 3 through the pipe 6D. The portion where the pipe 6C is connected to the reformer 5 and the portion where the pipe 6D is connected to the reformer 5 are separated from each other in the vicinity of one end and the other end in the longitudinal direction. As a result, the fuel gas and air supplied to the reformer 5 can sufficiently touch the reforming catalyst.

  A reforming catalyst is enclosed in the reformer 5. As the reforming catalyst, a catalyst in which nickel is applied to the surface of the alumina sphere and a catalyst in which ruthenium is applied to the surface of the alumina sphere are appropriately used. These reforming catalysts are spheres.

  In the present embodiment, the flow path member 7 is provided so as to cover the reformer 5 and each fuel cell stack 400. The flow path member 7 includes air flow path outer walls 71 and 72, an air distribution chamber 73, air collecting chambers 74 and 75, air flow path pipes 76a, 76b, 77a and 77b, and outer walls 78 and 79. Yes. The flow path member 7 is formed such that the air flow path outer walls 71 and 72 are arranged in the longitudinal direction and the outer walls 78 and 79 are arranged in the short direction, respectively, and are formed into a box shape by these members. The flow path member 7 is erected on the partition plate 15 so as to cover the reformer 5 and each fuel cell stack 400. In the following description, the side that contacts the partition plate 15 of the flow path member 7 is defined as the lower side, and the side opposite to the lower side is described as the upper side.

  The air distribution chamber 73 is attached to the upper outside of the outer wall 79. That is, the air distribution chamber 73 is attached to the outside of the box-shaped body formed by the air flow path outer walls 71 and 72 and the outer walls 78 and 79 and above the short side. An air supply pipe 7A is connected to the air distribution chamber 73, and air as an oxidant gas is supplied. Air flow passages 76a, 76b, 77a, 77b are also connected to the air distribution chamber 73.

  The air flow path pipes 76a and 76b are arranged along the air flow path outer wall 71 on the inner side of the box-shaped body formed by the air flow path outer walls 71 and 72 and the outer walls 78 and 79 and above the longitudinal side. Yes. The air channel tube 76a is disposed on the air channel outer wall 71 side, and the air channel tube 76b is disposed on the inner side of the air channel tube 76a. One end of each of the air flow path pipes 76 a and 76 b passes through the outer wall 79 and is connected to the air distribution chamber 73, and the other end is connected to the air collecting chamber 74. Therefore, the air that has flowed into the air distribution chamber 73 flows through the air flow path pipes 76a and 76b into the air collecting chamber 74 and rejoins.

  The air flow path pipes 77a and 77b are arranged along the air flow path outer wall 72 on the inner side and the upper side of the box-shaped body formed by the air flow path outer walls 71 and 72 and the outer walls 78 and 79. Yes. The air flow path pipe 77a is disposed on the air flow path outer wall 72 side, and the air flow path pipe 77b is disposed on the inner side of the air flow path pipe 77a. One end of each of the air passage pipes 77 a and 77 b passes through the outer wall 79 and is connected to the air distribution chamber 73, and the other end is connected to the air collecting chamber 75. Accordingly, the air flowing into the air distribution chamber 73 flows through the air flow path pipes 77a and 77b into the air collecting chamber 75 and rejoins.

  The air collecting chambers 74 and 75 are attached to the upper inside of the outer wall 78. That is, the air collecting chambers 74 and 75 are attached to the inside of the box-like body formed by the air flow path outer walls 71 and 72 and the outer walls 78 and 79 and above the short side. The air collecting chamber 74 is disposed so as to be in close contact with the air flow path outer wall 71, and the air that has flowed into the air collecting room 74 is configured to flow out to the air flow path outer wall 71. On the other hand, the air collecting chamber 75 is disposed so as to be in close contact with the air flow path outer wall 72, and the air flowing into the air collecting chamber 75 is configured to flow out to the air flow path outer wall 72.

  Each of the air flow path outer walls 71 and 72 has a double wall structure, and is configured so that air can flow through each of them. More specifically, the air flow path outer wall 71 has a structure divided into three chambers from above, and is formed as a first chamber 711, a second chamber 712, and a third chamber 713 in order from the top. The air that flows from the air collecting chamber 74 flows into the first chamber 711, then flows into the second chamber 712, and then flows into the third chamber 713. Similarly, the air flow path outer wall 72 is also divided into three chambers from above, and is formed as a first chamber 721, a second chamber 722, and a third chamber 723 in this order from the top. The air flowing from the air collecting chamber 75 flows into the first chamber 721, then flows into the second chamber 722, and then flows into the third chamber 723.

  In the third chambers 713 and 723, a plurality of air inflow holes 713a and 723a are formed at predetermined intervals, respectively. The air inflow holes 713a and 723a are positions facing the gaps between the fuel cells 4 in the direction in which the fuel cell stack 400 is connected, and the vertical positions with respect to the fuel cells 4 are substantially the same. A plurality of them are formed.

  The air flowing into the air flow path outer walls 71 and 72 is configured to flow into the vicinity of the fuel cell 4 in the power generation chamber 16 through the air inflow holes 713a and 723a. The air that has flowed through the air inflow holes 713 a and 723 a flows from the lower side to the upper side of each fuel cell 4 through the outside of the fuel cell 4. That is, the space along the outside of the fuel cell 4 functions as an oxidant gas flow path 51 formed outside the fuel cell 4. The air that has reached the upper side of each fuel cell 4 passes through the ventilation portion 100 that is a gap formed between the upper support plates 400 a, flows into the combustion portion 18, and is the fuel gas of each fuel cell 4. Combusted together with the fuel gas that has passed through the flow path 50.

  Above each fuel cell stack 400 is a combustion section 18 in which air and fuel gas are mixed and burned. The fuel gas rises from the gas tank 3 toward the combustion unit 18 through the fuel gas flow path 50 of the fuel cell 4 and via the connection flow path (40c or 42c) of the electrode terminal disposed on the upper side. . That is, the part opened upwards of the connection flow path 40c or the connection flow path 42c functions as a residual gas discharge port.

  Further, the air flowing outside the fuel cell 4 also passes through the oxidant gas flow path 51 and rises toward the combustion unit 18. An ignition device insertion hole 724 is provided in a portion corresponding to the combustion portion 18 of the air flow path outer wall 72, and an ignition plug FP for starting combustion of combustion gas and air is provided from the ignition device insertion hole 724 to the combustion portion 18. It is protruding. The spark generated by the ignition plug FP induces combustion of the air-fuel mixture in which fuel gas and air are mixed, and is ignited and burned. The fuel cells 4 constituting the fuel cell stack 400 are heated from above by the combustion unit 18. Further, the air flowing in through the air inflow holes 713a and 723a is also heated by the combustion in the combustion section 18 while passing through the air passage tubes 76a, 76b, 77a and 77b and the air passage outer walls 71 and 72 as described above. Is done.

  In the combustion section 18, the exhaust gas generated by the combustion of the fuel gas and the air flows into the exhaust gas chamber 17 through the gap 15b. More specifically, the exhaust gas generated by the combustion and mixing of the fuel gas and air in the combustion unit 18 passes through an exhaust gas flow path (not shown in the drawing) formed in the cover member 1. It faces downward and flows into the exhaust gas chamber 17 from the gap 15b. The exhaust gas flowing into the exhaust gas chamber 17 is exhausted from the exhaust port 11 to the outside.

  Next, specific structures and arrangements of the temperature sensor 800 and the protective tube 820 will be described with reference to FIG. In FIG. 7, the structure of the part where the temperature sensor 800 is attached to the air flow path outer wall 71 constituting the wall surface of the container 80 is schematically shown. In the figure, the inner wall of the air channel outer wall 71 having a double wall structure is not shown.

  As already described, the air flow path outer wall 71 constituting the wall surface of the container 80 has the heat insulating material 8 disposed on the outer side thereof, and the cover member 1 is further disposed on the outer side thereof. In order to arrange the temperature sensor 800 in a state of passing through them, a first insertion hole 851 is formed in the air flow path outer wall 71, and a second insertion hole 852 is formed in the heat insulating material 8. The cover member 1 has a third insertion hole 853 formed therein. These are all formed in a circular shape, and are arranged so that their center positions are aligned along a direction perpendicular to the outer wall 71 of the air flow path.

  The temperature sensor 800 has a rod-like shape having a circular cross section, and its central axis is the center position of the first insertion hole 851, the center position of the second insertion hole 852, and the center of the third insertion hole 853. It is arranged to pass through all of the positions. Since the thermocouple 801 disposed at one end of the temperature sensor 800 is a temperature measuring unit, the thermocouple 801 is disposed at a desired position where the temperature is to be measured inside the container 80. However, the temperature sensor 800 is arranged at a position spaced apart from all the structures arranged inside the container 80 so that the protective tube 820 described below does not interfere with the fuel battery cell 4 and the like. Is done.

  The protection tube 820 is a cylindrical tube arranged to cover the temperature sensor 800 for the purpose of protecting the temperature sensor 800. One end side 821 of the protective tube 820 is opened, and the opened one end side 821 is welded to the air flow path outer wall 71. Accordingly, the protective tube 820 is fixed to the air flow path outer wall 71 in a state of protruding toward the inside of the container 80. Since the other end 822 of the protective tube 820 is sealed, high temperature oxidant gas or the like is prevented from flowing from the inside of the container 80 toward the inside of the protective tube 820.

  In the present embodiment, the protective tube 820 is fixed to the wall surface of the container 80, that is, the air flow path outer wall 71, and the heat insulating material 8 is disposed so as to contact the outside of the air flow path outer wall 71. Therefore, it is possible to prevent the protection tube 820 and the air inside the protection tube 820 from being cooled by heat conduction from the air outside the container 80. Furthermore, the opening area of the second insertion hole 852 formed in the heat insulating material 8 is smaller than the opening area of the first insertion hole 851 formed in the air flow path outer wall 71. Thereby, the air inside the protective tube 820 and the air outside the container 80 are separated by the heat insulating material 8. Therefore, it is possible to prevent the air inside the protective tube 820 from being directly cooled by heat conduction through the cap member 902 and the bush 920.

  In the present embodiment, as described above, since the air outside the container 80 is prevented from affecting the temperature measurement, the temperature inside the container 80 is accurately measured by the temperature sensor 800. It is possible.

  In particular, even when the volume of the protective tube 820 is increased, that is, when the inner diameter of the protective tube 820 is increased, the temperature of the protective tube 820 does not decrease, and the air inside the protective tube 820 is reduced. The temperature does not drop. Therefore, the inside of the container 80 can be accurately measured while the seizure between the protective tube 820 and the temperature sensor 800 is reliably prevented by forming the protective tube 820 with a large volume.

  Next, a specific structure for fixing the temperature sensor 800 will be described. A cylindrical cap receiver 900 is formed outside the cover member 1 so as to surround the third insertion hole 853, and a fourth insertion hole 854 is formed at the center of the cap receiver 900. A cap member 902 is attached.

  When fixing the temperature sensor 800, first, with the cap member 902 removed, the first insertion hole 851, the second insertion hole 852, and the third insertion hole 853 are passed, and the position of the thermocouple 801 is determined. The temperature sensor 800 is arranged so as to be in an appropriate position. Subsequently, a bush 920 made of a highly elastic material is disposed in a space 904 formed inside the cap receiver 900. In the present embodiment, the bush 920 is formed of ceramic paper. The bush 920 is inserted into a gap 905 formed between the temperature sensor 800 and the cover member 1 in a later process and seals the entire gap 905. Therefore, at least around the temperature sensor 800 is provided. It arrange | positions so that it may surround continuously.

  Subsequently, the cap member 902 is attached to the cap receiver 900. A first screw portion 901 is formed on the outer surface of the cap receiver 900, and a second screw portion 903 that is screwed with the first screw portion 901 is formed on the inner surface of the cap member 902. . After passing the temperature sensor 800 through the fourth insertion hole 854 formed in the cap member 902, the first screw portion 901 and the second screw portion 903 are screwed together. From this state, when the cap member 902 is rotated while applying a force so as to further fasten the two, the cap member 902 advances toward the cover member 1 (to the left in FIG. 7).

  Here, a protrusion 906 is provided on the bottom surface of the cap member 902. For this reason, as the cap member 902 advances toward the cover member 1, the bush 920 is pressurized by the protrusion 906. When the cap member 902 is further rotated by applying a force, the bush 920 is further pressurized and deformed, and is inserted between the third insertion hole 853 and the temperature sensor 800. As a result, the temperature sensor 800 is fixed to the cover member 1 via the bush 920. Further, the gap 905 formed between the temperature sensor 800 and the cover member 1 is completely sealed by the deformed bush 920.

  As described above, in the present embodiment, the temperature sensor 800 is fixed to the cover member 1. Since the cover member 1 is provided via the heat insulating material 8 with respect to the air flow path outer wall 71 which becomes high temperature, the temperature sensor 800 is not heated by heat conduction. Therefore, the temperature inside the container 80 can be accurately measured. In addition, the bush 920 which is a member different from the cover member 1 is inserted into the third insertion hole 853 formed in the cover member 1 instead of directly fixing the temperature sensor 800 to the cover member 1. The bush 920 holds the temperature sensor 800. Therefore, the temperature sensor 800 can be fixed via a material having higher elasticity than the cover member 1, and it is possible to reliably prevent air outside the container 80 from flowing into the protective tube 820. .

  Furthermore, a cap member 902 that is screwed into and fastened to a first screw portion 901 formed in the cover member 1 is further provided, and the bush 920 is pressurized by the cap member 902 as the cap member 902 is fastened. Thus, the bush 920 is fitted into the gap 905. Therefore, the temperature sensor 800 can be fixed in a sealed state with respect to the cover member 1 with a simple configuration, and air outside the container 80 can be prevented from flowing into the protective tube 820.

  In the present embodiment, the first insertion hole 851 formed in the outer wall 71 of the air flow path is formed so as to have substantially the same shape as the inner edge of the protective tube 820. With such a configuration, the work of welding the protective tube 820 to the air flow path outer wall 71 becomes easy. Therefore, a leak hole is formed between the protective tube 820 and the air flow path outer wall 71 due to a welding error. It is prevented from forming. Accordingly, since no gas flows from the outside of the protective tube 820 through the leak hole, the temperature inside the container 80 can be accurately measured by the temperature sensor 800.

  The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. In other words, those specific examples that have been appropriately modified by those skilled in the art are also included in the scope of the present invention as long as they have the characteristics of the present invention. For example, the elements included in each of the specific examples described above and their arrangement, materials, conditions, shapes, sizes, and the like are not limited to those illustrated, and can be changed as appropriate. Moreover, each element with which each embodiment mentioned above is provided can be combined as long as technically possible, and the combination of these is also included in the scope of the present invention as long as it includes the features of the present invention.

1: Cover member 2: Base member 2a: Hole 3: Gas tank 4: Fuel cell 4a: End 4b: End 5: Reformer 6A: Reformed gas supply pipe 6B: Steam supply pipe 6C: Piping 6D: Piping 7: Channel member 7A: Air supply pipe 8: Heat insulating material 11: Exhaust port 13, 14: Electrode rod 15: Partition plate 15a: Support member 15b: Gap 15c: Mixing chamber 16: Power generation chamber 17: Exhaust gas chamber 18 : Combustion part 30: Fuel cell unit 30c: In-pipe flow path 40: Inner electrode terminal 40a: Main body part 40b: Tubular part 40c: Connection flow path 40d: Step part 42: Outer electrode terminal 42a: Main body part 42b: Tubular part 42c : Connection channel 42d: Step 44: Electrode layer 44a: Inner electrode exposed peripheral surface 44b: End surface 44c: End surface 46: Electrolyte layer 46a: Electrolyte exposed peripheral surface 48: Electrode layer 48a: Outer side Electrode exposed peripheral surface 50: Fuel gas flow path 51: Oxidant gas flow path 52: Insulating member 54: Sealing material 71: Air flow path outer wall 72: Air flow path outer wall 73: Air distribution chamber 74: Air collection chamber 75: Air Aggregation chamber 76a, 76b, 77a, 77b: Air flow pipe 78: Outer wall 79: Outer wall 80: Container 100: Ventilation part 400: Fuel cell stack 400a: Upper support plate 400b: Lower support plate 400c: Connection member 400d: External Terminal 500: Fuel cell assembly 711: First chamber 712: Second chamber 713: Third chamber 713a, 723a: Air inlet 721: First chamber 722: Second chamber 723: Third chamber 724: Ignition device insertion Hole 725: Combustion detector insertion hole 800: Temperature sensor 801: Thermocouple 802: Lead wire 820: Protection tube 821: One end 822: Other end 851: First insertion 852: Second insertion hole 853: Third insertion hole 854: Fourth insertion hole 900: Cap receiver 901: First screw portion 902: Cap member 903: Second screw portion 904: Space 905: Clearance 906 : Protrusion 920: Bush FC: Fuel cell device FP: Ignition plug FS: Combustion detector

Claims (5)

In a fuel cell device that generates power using fuel gas and oxidant gas,
A plurality of fuel cells having an internal flow path and supplied with one of the fuel gas and the oxidant gas to the internal flow path;
A container that houses the plurality of fuel cells, and
A heat insulating material arranged to come into contact with the wall surface of the container from the outside;
Through the first insertion hole formed in the wall surface and the second insertion hole formed in the heat insulating material, the thermocouple provided at the tip protrudes inside the container so as to be located inside the container. A rod-shaped temperature sensor arranged;
Inside the container, a protective tube fixed to the wall surface so as to cover the temperature sensor and the first insertion hole,
With
The fuel cell device according to claim 1, wherein an opening area of the second insertion hole is smaller than an opening area of the first insertion hole.   The fuel cell device according to claim 1, further comprising a cover member that covers the heat insulating material outside the heat insulating material, and the temperature sensor is fixed to the cover member.   A third insertion hole is formed in the cover member at a position corresponding to the second insertion hole, and gas outside the container flows into the protective tube into the third insertion hole. The fuel cell device according to claim 2, wherein a bush for holding the temperature sensor is inserted in a state where the path is cut off.   The cover member has a screw portion formed at a position corresponding to the third insertion hole, and further includes a cap member that is screwed and fastened to the screw portion, and the bush includes the cap 4. The fuel cell device according to claim 3, wherein the fuel cell device is inserted between the third insertion hole and the temperature sensor by being pressurized by the cap member as the member is fastened.   2. The fuel cell device according to claim 1, wherein the first insertion hole is formed to have substantially the same shape as an inner edge in a cross section perpendicular to the axial direction of the protective tube.

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