JP2013065506A - Fuel cell device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell device enabling its use over a long period of time without exchanging an ignition plug by suppressing performance degradation of the ignition plug and capable of reliably inducing combustion in a combustion part.SOLUTION: In the fuel cell device, either a first electrode 202 or a second electrode 203 constituting an ignition plug FP does not overlap on a residual gas exhausting part 208 in a top view while a discharge part 206 formed between the first electrode 202 and the second electrode 203 is disposed so that at least a part thereof is overlapped on the residual gas exchanging part 208 in a top view.

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 A fuel cell device that generates power using fuel gas and oxidant gas has a structure in which a plurality of fuel cell cells having fuel gas flow paths formed therein are electrically connected to each other to form a fuel cell cell assembly. It has been. In the fuel cell apparatus having such a structure, the fuel gas and the oxidant gas used for power generation are generally supplied so as to flow from the lower part to the upper part of the fuel cell.

  Of the fuel gas and oxidant gas supplied from the lower part of the fuel cell, the remaining fuel gas that has not contributed to power generation and the remaining oxidant gas are merged and mixed in the upper part of the fuel cell. The mixed residual fuel gas and residual oxidant gas are configured so that the remaining fuel gas is not discharged to the outside as it is by burning in the combustion section formed in the upper part of the fuel cell. ing. The heat generated by the combustion is used for heating a reformer disposed on the upper part of the fuel cell, maintaining the temperature of the fuel cell, or the like.

  The following Patent Document 1 is disclosed as a proposal of such a fuel cell device. Specifically, a fuel cell device having a structure in which an ignition plug having two electrodes spaced apart from each other is arranged on the upper part of a fuel cell and the combustion in the combustion part is induced by a spark generated from the ignition plug.

JP 2010-67547 A

  As in the fuel cell device described in Patent Document 1, when ignition is induced by a spark generated from the ignition plug and combustion is induced in the combustion section, the ignition plug is connected to the upper end of the fuel cell in order to ensure ignition. Must be placed close to That is, a residual gas discharge port for discharging residual fuel gas that has not been used for power generation is formed at the upper end of the fuel cell, so that the ignition plug is placed close to the upper end of the fuel cell. By doing so, the possibility that the fuel gas and the spark come into contact with each other and combustion is induced can be increased.

  However, when the ignition plug is brought close to the upper end of the fuel cell, there is a problem that the ignition plug is excessively heated by the heat generated in the combustion section. If the ignition plug is excessively heated, the electrode of the ignition plug is deteriorated, and the performance of the ignition plug is lowered. As a result, it was necessary to replace the ignition plug in a short period of time.

  The present invention has been made in view of such problems, and its purpose is to suppress the deterioration of the performance of the ignition plug, thereby enabling it to be used for a long period without replacement of the ignition plug. Another object of the present invention is to provide a fuel cell device that can reliably induce combustion in a combustion section.

  In order to solve the above-mentioned problems, a fuel cell device according to the present invention is a fuel cell device that generates power using fuel gas and oxidant gas, and is a plurality of fuels that are electrically connected to each other and constitute a fuel cell assembly. A fuel cell, a fuel gas flow path formed in the fuel cell so that the fuel gas supplied from the lower part of the fuel cell flows toward the upper part of the fuel cell, and the fuel cell Provided at the upper end of the fuel cell and an oxidant gas flow path formed outside the fuel cell so that the oxidant gas supplied from the lower part of the cell flows toward the upper part of the fuel cell. A residual gas discharge port that discharges the remaining fuel gas that has not been used for power generation among the fuel gas that has passed through the fuel gas flow path, and an upper portion of the fuel cell. In a top view of the fuel cell discharged from the gas outlet, a combustion part that is a space for mixing and burning the oxidant gas that has passed through the oxidant gas flow path, and an upper part of the fuel cell. Combustion of the fuel gas in the combustion part by having a first electrode and a second electrode arranged apart from each other, generating a spark in a discharge part formed between the first electrode and the second electrode The first electrode and the second electrode are arranged so as not to overlap the residual gas discharge port in a top view, while the discharge portion It is characterized in that at least a part thereof is arranged so as to overlap the residual gas discharge port in view.

  According to the present invention, the discharge part formed between the first electrode and the second electrode is arranged so that at least a part thereof overlaps with the residual gas discharge port in a top view. That is, since the discharge part which is a space through which a spark passes between the first electrode and the second electrode overlaps with the residual gas discharge port for discharging the fuel gas, combustion in the combustion part can be reliably induced. On the other hand, after the combustion is induced in the combustion section, a flame is formed in a portion immediately above the residual gas discharge port. According to the present invention, the first electrode and the second electrode constituting the ignition plug are arranged so as not to overlap with the residual gas discharge port when viewed from above. Therefore, since neither the first electrode nor the second electrode is directly exposed to the flame, it is possible to suppress the deterioration of the performance of the ignition plug due to excessive heating.

  In the fuel cell device according to the present invention, it is also preferable that at least one of the first electrode and the second electrode has a bent portion that is bent toward the other in the vicinity of the discharge portion.

  By having such a bent portion, the distance between the first electrode and the second electrode can be reduced in the vicinity of the discharge portion, while in the portion excluding the range of the bent portion from the discharge portion, The distance between the electrode and the second electrode can be increased. This makes it possible to place the first electrode and the second electrode far away from the flame in the other parts while reducing the distance between the electrodes to the extent that sparks are reliably generated in the vicinity of the discharge part. Thus, the performance deterioration of the ignition plug due to excessive heating can be further suppressed.

  In the fuel cell device according to the present invention, an upper support plate is disposed between the fuel cell and the combustion part, and the upper support plate receives the oxidant gas that has passed through the oxidant gas flow path. It has a ventilation part for letting it flow into the combustion part, and is at least one of the parts excluding the range from the bent part to the discharge part at least one of the first electrode and the second electrode. However, it is also preferable to be disposed at a position overlapping the ventilation portion in a top view.

  Even if the first electrode and the second electrode are arranged at a position where they are not directly exposed to the flame, the temperature of the first electrode and the second electrode rises to some extent due to the influence of radiation from the combustion part, and the deterioration of the ignition plug proceeds. End up. According to this preferred aspect, at least one of the first electrode and the second electrode, and at least a part of the portion excluding the range from the bent portion to the discharge portion, is disposed at a position overlapping the ventilation portion in a top view. . By adopting such an arrangement, at least one of the first electrode and the second electrode is cooled by the oxidant gas flowing into the combustion part through the ventilation part, so that the performance deterioration of the ignition plug due to excessive heating is prevented. Further suppression is possible.

  According to the present invention, by suppressing the deterioration of the performance of the ignition plug, the fuel that can be used for a long time without replacement of the ignition plug and can reliably induce combustion in the combustion section. A battery device 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 an ignition plug.

  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 is removed. FIG. 2 is a perspective view of the fuel cell device FC showing a state where the flow path member 7 covering the fuel cell assembly 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 cover member (not explicitly shown in FIGS. 1, 2, and 4. The outer shape is shown by a two-dot chain line in FIG. 3) includes a front side wall, a pair of side walls in the longitudinal direction, a side wall on the back side, and a ceiling. It is formed in a rectangular parallelepiped shape. A flange portion is formed at the lower end portion of each side wall, and a space sealed by the cover member and the base member 2 is formed by bringing the flange portion into contact with the base member 2. The cover member and the base member 2 are fixed by a bolt (not shown), and the bolt penetrates through an attachment hole provided in the cover member and is fixed by passing through an attachment hole 2a provided in the base member 2. Yes.

  The internal space formed by the cover member and the base member 2 is separated into two spaces by the 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 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 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 portion opened upward in the connection channel 40 c or the connection channel 42 c functions as the residual gas discharge port 208.

  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 when the fuel gas and air are mixed and burned in the combustion section 18 is not clearly shown in the cover member (FIGS. 1, 2, and 4). It flows downward through the exhaust gas flow path (not shown in the figure) formed in the dotted line) 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.

  A combustion detector insertion hole 725 is provided in the air flow path outer wall 71 at a portion facing the ignition device insertion hole 724. A combustion detection unit FS is inserted into the combustion detection unit insertion hole 725 and protrudes from the combustion unit 18. The combustion detection unit FS includes a temperature sensor and a frame rod. When the combustion detection part FS is comprised with the temperature sensor, it detects that combustion is performed by measuring the temperature rise of the part. When the combustion detection unit FS is configured by a frame rod, it is detected that combustion is performed by detecting that a flame is generated in that portion.

  Next, a specific structure and arrangement of the ignition plug FP will be described with reference to FIG. FIG. 7 shows a top view of the ignition plug FP disposed on the upper part of the fuel battery cell 4.

  The ignition plug FP includes a flange part 200, an electrode holding part 201, a first electrode 202, and a second electrode 203, and these are unit parts that are integrally attached to the fuel cell device FC.

  The flange portion 200 is a portion that is inserted into and fixed to an ignition device insertion hole 724 provided in the outer wall 72 of the air flow path. The fuel cell device FC and the ignition plug FP are connected by the flange portion 200. Therefore, in a state where the ignition plug FP is fixed to the fuel cell device FC, the first electrode 202 and the second electrode 203 are arranged so that the positional relationship between the fuel cell 4 and the combustion part 18 is appropriate. The length and position where the 202 and the second electrode 203 protrude from the flange portion 200 are adjusted.

  The electrode holding part 201 is fixed in a state of penetrating the flange part 200, and holds the first electrode 202 and the second electrode 203 in a state of being separated and insulated from each other. The first electrode 202 and the second electrode 203 are a pair of electrodes made of a rod-like metal, and are spaced apart from each other when viewed from above. By causing a spark discharge between them, combustion in the combustion section 18 is induced.

  One end portions 204a and 204b of the first electrode 202 and the second electrode 203 are both exposed outside the outer wall 72 of the air flow path, and an ignition power source (not shown) is connected to the exposed portions. The ignition power supply is a power supply device for supplying electric power for generating sparks to the ignition plug FP, and supplies electric power to the ignition plug FP in accordance with an instruction signal output from a CPU as a control unit. Is. When the fuel cell device is activated, the instruction signal is output at an appropriate timing when the supply of fuel gas is started, and combustion in the combustion unit 18 is induced.

  The other end portions 205a and 205b of the first electrode 202 and the second electrode 203 protrude above the fuel cell assembly 500 inside the air flow path outer wall 72, and are sandwiched between the other end portions 205a and 205b. A discharge portion 206 is formed as a straight space. When electric power is supplied to the ignition plug FP by the ignition power source, a large potential difference is generated between the first electrode 202 and the second electrode 203, along a substantially linear path from the other end 205a to the other end 205b. Sparks move. The path along which the spark moves is the discharge unit 206.

  The first electrode 202 and the second electrode 203 are arranged so as to be parallel to each other in almost all parts except the vicinity of the discharge part 206. On the other hand, in the vicinity of the discharge portion 206, each electrode has bent portions 207a and 207b, and the portion closer to the discharge portion 206 than the bent portions 207a and 207b is bent toward the other electrode. Yes. In other words, the first electrode 202 and the second electrode 203 are bent so that the tips thereof are close to each other.

  As shown in FIG. 7, the discharge part 206 formed between the first electrode 202 and the second electrode 203 is arranged so that at least a part thereof overlaps the residual gas discharge port 208 in a top view. . That is, since the discharge part 206 which is a space through which a spark passes between the first electrode 202 and the second electrode 203 overlaps with the residual gas discharge port 208 for discharging the fuel gas, combustion in the combustion part 18 is surely induced. can do.

  On the other hand, the first electrode 202 and the second electrode 203 are arranged so as not to overlap with the residual gas discharge port when viewed from above. By arranging in this way, neither the first electrode 202 nor the second electrode 203 is directly exposed to the flame. Therefore, it is suppressed that the performance of the ignition plug is deteriorated due to excessive heating of the first electrode 202 and the second electrode 203.

  In addition, since both the first electrode 202 and the second electrode 203 according to the present embodiment have the bent portions 207a and 207b, the first electrode 202 and the second electrode 203 are disposed in the vicinity of the discharge portion 206. While the distance is reduced, the distance between the first electrode 202 and the second electrode 203 is increased in the portion excluding the range of the bent portions 207a and 207b from the discharge portion 206. As a result, the distance between the electrodes is reduced to such an extent that sparks are surely generated in the vicinity of the discharge portion 206, while in the other portions, the first electrode 202 and the second electrode 203 are both moved away from the flame. Arrangement and suppression of performance deterioration of the ignition plug due to excessive heating.

  Furthermore, in the present embodiment, the first electrode 202 is disposed immediately above the ventilation portion 100 formed between the plurality of upper support plates 400a. By arranging in this way, the first electrode 202 is cooled by the oxidant gas flowing into the combustion part 18 through the ventilation part 100, so that the performance deterioration of the ignition plug FP due to excessive heating of the ignition plug FP. Suppressed.

  In the present embodiment, an example in which the entire portion of the first electrode 202 excluding the range from the bent portion 207a to the discharge portion 206 is disposed at a position overlapping the ventilation portion 100 in a top view is shown. However, the same effect can be obtained if part of the first electrode 202 excluding the range from the bent part 207a to the discharge part 206 overlaps with the ventilation part 100. In addition to the first electrode 202, a part of the second electrode 203 can be arranged at a position overlapping the ventilation part 100. In that case, since both the first electrode 202 and the second electrode 203 are cooled by the oxidant gas, it is possible to further suppress the deterioration in performance of the ignition plug FP due to excessive heating of the ignition plug FP.

  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.

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: Pipe 6D: Pipe 7: Flow Road member 7A: Air supply pipe 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 section 30: Fuel cell Unit 30c: In-pipe flow path 40: Inner electrode terminal 40a: Main body portion 40b: Tubular portion 40c: Connection flow path 40d: Step portion 42: Outer electrode terminal 42a: Main body portion 42b: Tubular portion 42c: Connection flow passage 42d: Step portion 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 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 collection chamber 76a, 76b, 77a, 77b: Air channel pipe 78: Outer wall 79: Outer wall 100: Ventilation part 200: Flange part 201: Electrode holding part 202: First electrode 203: Second electrode 204a, 204b: One end part 205a, 205b: Other end part 206: Discharge portion 207a, 207b: bent portion 208: residual gas discharge port 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 detection unit insertion hole FC: Fuel cell device FP: Ignition plug FS: Combustion detection unit

Claims (3)

In a fuel cell device that generates power using fuel gas and oxidant gas,
A plurality of fuel cells that are electrically connected to each other and constitute a fuel cell assembly;
A fuel gas flow path formed inside the fuel battery cell such that the fuel gas supplied from the lower part of the fuel battery cell flows toward the upper part of the fuel battery cell;
An oxidant gas flow path formed outside the fuel battery cell so that the oxidant gas supplied from the lower part of the fuel battery cell flows toward the upper part of the fuel battery cell;
A residual gas outlet that is provided at an upper end of the fuel cell and discharges the remaining fuel gas that has not been used for power generation out of the fuel gas that has passed through the fuel gas flow path;
A combustion section that is a space for mixing and burning the fuel gas discharged from the residual gas discharge port with the oxidant gas that has passed through the oxidant gas flow path in the upper part of the fuel cell;
An upper portion of the fuel cell has a first electrode and a second electrode that are spaced apart from each other in a top view, and generates a spark in a discharge portion formed between the first electrode and the second electrode And an ignition plug that induces combustion of the fuel gas in the combustion section,
While the first electrode and the second electrode are arranged so as not to overlap the residual gas discharge port in a top view,
The fuel cell device according to claim 1, wherein the discharge part is arranged so that at least a part of the discharge part overlaps the residual gas discharge port in a top view.   2. The fuel cell device according to claim 1, wherein at least one of the first electrode and the second electrode has a bent portion that is bent toward the other in the vicinity of the discharge portion. An upper support plate is disposed between the fuel cell and the combustion part, and the upper support plate is a ventilation part for allowing the oxidant gas that has passed through the oxidant gas flow path to flow into the combustion part. Having
At least one of the first electrode and the second electrode, and at least a portion of the portion excluding the range from the bent portion to the discharge portion, is disposed at a position overlapping the ventilation portion in a top view. The fuel cell device according to claim 2, wherein the fuel cell device is characterized.

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